Wednesday, February 26, 2014

The Importance of Good Modulation

Searching for a new DX target got me to thinking about something I have noticed about a number of Shortwave Broadcast Stations. Many have good signals but are all but unreadable or unlistenable because of poor audio. I am not sure if this is coming about because of a lot of automation and lack of monitoring, or something else.

This came about because it appears that my new DX target will have pretty good audio. The posts that have me looking have been telling of Horizon FM in Tenerife ( Canary Islands) being relayed on 5780 kHz. I am not sure if its the station itself doing this or some hobby group. The posts seem to indicate they are starting with 75 watts and an inverted V antenna up about fifty feet. One post quoted the broadcasters as saying they would be processing the audio with an Optimod audio processor.

This gave me hope of hearing them for two reasons. First the Optimod in all its versions is a pretty good device for, as it name implies “optimizing the modulation”. And second, because this indicates that those involved in putting the transmitter on the air “ get it”. You have to get good audio into the transmitter for the listener to get good audio out of the receiver!

With Amplitude Modulation (AM) there are two parts to the signal: The Carrier and the Sidebands. The sidebands carrier the intelligence. In regular AM there are two, upper and lower, with the bandwidth being equal to the highest audio frequency transmitted. In other words, a tone of 5000 Hz will result in sidebands 5000 Hz above and below the carrier wave.

The more power in the sidebands, the more power can be recovered by the receiver. At one hundred percent modulation, the maximum power radiated is FOUR TIMES the unmodulated carrier power. Therefore it is important to keep the modulation at as high a level as possible. This is made somewhat difficult because complex audio is made up of different frequencies with different levels. Each instant of audio is not at the same level as it is the next instant. In order to keep the transmitter from being overmodulated, the overall level must be set so the highest peak does not go over 100 percent.

It might seem a simple matter just to keep the level going into the transmitter turned down to the point that the highest peak does not go over 100 percent. But if that is done, the other peaks would not reach that high and some effective power would be lost. There is also the average power in the audio to be considered. It is actually that average power that gives the impression of “loudness” and provides the real secret to having the station well heard above the noise and the clutter on the band.

To further complicate the issue, different forms of audio are complex in another way. There is what is known as the “peak-to-average” ratio. Human speak particularly has a much wider divergence between its peak power and its average power, so even if one were to be able to keep one's hand on the level control and somehow constantly juggle it to keep peaks and valleys near 100 percent, some program content would have less average power than others. The music or prerecorded material would always sound louder than the plain speech.

The answer is in forms of automatic level control. This is done with devices at two different levels. The first is called “ compression”. The compressor works very much like a human hand on the gain control, riding the gain and keeping the general program level fairly constant. It usually has a fairly slow attack and recovery time and follows the average program levels.

Then there is the peak limiter that follows it. This device actually works on that “ peak-to-average” ratio mentioned earlier. It works much faster and takes the errant high peaks and pulls them down to the general level of everything else. This is especially important with speech.

There are two other areas that have to be dealt with in what is termed in the trade (audio processing”. One is the fact that some forms of audio, particularly human speech, is not symmetric in its wave form. The positive and negative swings of the wave are not always equal. In Amplitude Modulation it is particularly important not to go over 100 percent modulation in the negative direction because this can cause extreme distortion and “splatter”...interference with stations on adjacent frequencies. It is also a waste of power that could be used to make the signal stronger for the desired listener. Modulation in the positive direction is less concerning in this regard. If a peak goes over what is termed 100 percent in the positive direction, the peak just continues to rise and actually delivers more power to the receiver.

The trick is that one never knows on which side this asymmetry will occur. Some peak limiters have been designed to sense this asymmetry and to electronically invert or “ flip over” if you will, the wave form so that the highest peak is always positive. If memory serves me right I believe the CBS Volumax limiter was the first widely distributed device to do this, with others following suit during the 1960's and 70's.

With both peak limiting and compression, time of recovery and attack determine just how “dense” the audio becomes. There is a limit, however, to how far you can take this. On low frequency notes, if you recover too fast, you actually cause gain recovery on part of the cycle itself and the device tries to turn the pretty sine waves of a bass into a square wave. On the other end of the spectrum, short duration percussion sounds would be so high and so short in duration that they would force the compressor or limiter to audibly “ push down” the mid range frequencies giving the impression of punching holes in the audio or giving a “pumping” impression.

During the 70's Mike Dorrough developed a multi band compressor that took care of that problem, by splitting the audio spectrum up into sections or bands and processing each separately, with slower attack and recovery times for the low frequencies, faster for mid range, and really, really fast for the highs. Many of the better processors today use this idea.

Then we get back to bandwidth. If the receiver was broad band enough to pass the entire audio spectrum, this would be the end of the story. But since regular AM broadcast receivers are not that broadband ( hearing interference from adjacent channel stations would be the result of that) any power transmitted by our station that falls outside that bandwidth is not only wasted, it causes interference to other stations nearby on the dial.

For that reason, on AM and Shortwave transmitters, it is prudent to limit the bandwidth of the transmitted signal to that which it is expected a receiver will pass. For standard medium wave stations in the US, this would be about 7500 Hz or less. For shortwave stations, it would be less...and in fact may be mandated to be less by some licensing agencies. Therefore, there is usually some form of filtering done to roll off the higher, less useful and often offending frequencies.

There is another area of power waste in the extreme low frequencies. In older transmitters that used high level plate modulation with large transformers to couple the audio from the modulator to the final amplifier, low frequencies at high levels could saturate the transformers, resulting in heating, but also in distortion and lost power. With listeners using smaller portable radios with small speakers that could not reproduce those lows anyway, this power was simply wasted. Even with todays “ boom boxes” it might be argued that the extreme lows are not that useful to the shortwave broadcaster anyway. It kind of depends on who the listener is expected to be and whether quality of music transmission or readability of speech programming is more important. The frequencies in speech that deliver understandability are not necessarily the extreme low end. For that, individual preference of the programmer comes into play. And for that, a higher grade version of the familiar graphic equalizer used in some home audio systems comes in to play.

In any event, it behooves the broadcaster to shape the baseband of his transmitted audio to fit the bandwidth and preferences of the receiver and listener where the sound will come out.

With limited bandwidth, it might seem to some audio purists that the sound would become dull and muddy, and in fact without some further enhancement it might. However, with some judicious reshaping of the frequency response of the audio chain in the upper midrange, where the consonant sounds of speech are generated and the beginning of what is know as the “presence band” begins, this can be overcome. By boosting audio frequencies in the 2500-5000 Hz range a bit with rapid rolloff above, one can put a bit of the “edge” back into the signal and the human ear and brain makes adjustments to fill in the rest. The ear is somewhat fooled into thinking it is hearing higher highs than it does.

The difference between the signal from a well processed transmitter and a non processed transmitter is not just minor...its phenomenal. The average audio is much higher, appears louder, overcomes noise and interference and becomes more listenable during less than optimal conditions.

The effect cannot be obtained just by putting a few boxes between the studio and the transmitter. The entire system must be considered. If the studio sends out audio that is distorted to begin with or is filled with hum or noise, those problems will only be magnified by the processing. The noise or hum will rise between syllables of speech or in pauses in the music. The path from the studio to the transmitter, whether it be telephone line, microwave or satellite link or internet connection must be able to handle the higher density audio and must not introduce their own distortion or noise. And the final peak limiter should be right at the transmitter input.

The transmitter itself must be in good condition. Tubes in the modulator cannot be of low emission or gassy or weak in general or there will be distortion. Tubes in the final amplifier must be able to deliver the positive peak output of the asymmetric audio or the positive peaks will be clipped off in the RF stage resulting in distortion or splatter. High voltage power supplies must be in good condition to supply the higher average currents and have voltage regulation to handle the extra current drawn during asymmetric, high positive peak modulation.

I have seen this work very well in standard medium wave broadcasting back in the dyas before FM dominated the music broadcasting world. How well does it work? In one station where I did the engineering we were on a crowded “ graveyard” channel-1340 kHz, with a power of 1000 watts day and 250 watts night. Many of our listeners in a nearby city were in an area that at night suffered some skywave and other distant station interference. With good processing, we were able to keep our audio above the clutter and gained many listeners. During the day the station was audible and listenable almost a hundred miles away. We were noticeably louder and “ bigger” sounding than our competition that ran the same power and were even noticeably louder on the dial than our other competitor that was a 5000 watt station. We had more audio coming out of the radio than they did, simply because they were not taking advantage of what they had.

It is somewhat disturbing, then, to tune across the bands and hear a large, international broadcaster burning up lots of power lighting up a 100 or 250 kilowatt transmitter and having it almost unlistenable because of low audio, poor modulation, or simply levels not set to achieve the optimum level of modulation. Given the cost of electricity and for some, the importance of getting a message out, that they would take note. And of course, for the DX-er, if they would, perhaps that station might more easily be entered into a log!

Monday, February 24, 2014

New Transworld Radio Swaziland Transmitter Schedule

For SWL's seeking to log Swaziland, courtesy of a new friend with TWR, here is the new schedule for the coming season. Somehow the formatting is not working quite right in reposting it here, but the columns are easily discernible I think, and I hope it will be useful.
Happy DX-ing!

23nd March 2014 to 25th October 2014
0255-0325 12345 Ndebele 90 3200 50 8 3 Zimbabwe
0255-0310 6 Ndebele 90 3200 50 8 3 Zimbabwe
0255-0325 7 English 90 3200 50 8 3 Zimbabwe
0255-0325 1234567 Shona 90 3240 50 6 3 Zimbabwe
0325-0340 1234567 Ndau 90 3240 50 6 3 Zimbabwe
0330-0345 34 Sidamo 31 9530 100 102 13 Ethiopia
0330-0345 1 5 7 Amharic 31 9530 100 102 13 Ethiopia
0330-0345 2 Oromo 31 9530 100 102 13 Ethiopia
0342-0357 1234567 Lomwe 60 4775 50 8 3 Mozambique
0400-0430 12345 German 90 3200 50 9 233 South Africa
0400-0500 67 German 90 3200 50 9 233 South Africa
0400-0430 12345 German 60 4775 50 4 233 South Africa
0400-0500 67 German 60 4775 50 4 233 South Africa
0400-0445 67 Chewa 49 5995 100 11 5 Malawi
0430-0500 12345 English 90 3200 50 9 233 South Africa
0430-0800 12345 English 60 4775 50 4 233 Southern Africa
0500-0800 67 English 90 4775 50 4 233 Southern Africa
0501-0800 1234567 English 49 6120 50 4 233 Southern Africa
0500-0800 1234567 English 31 9500 100 11 5 Central Africa
1400-1415 1234567 Urdu 19 15360 100 103 43 Pakistan
1425-1455 1234567 Portuguese 41 7315 50 11 5 Mozambique
1455-1510 1234567 Makua 41 7315 50 11 5 N Mozambique
1510-1555 1234567 Lomwe 41 7315 50 11 5 N Mozambique
1455-1525 12345 Malagasy 31 9585 100 3 64 Madagascar
1440-1525 67 French 31 9585 100 3 64 Madagascar
1425-1455 1234567 English 49 6025 100 6 3 Zimbabwe
1455-1525 1234567 Shona 49 6025 100 6 3 Zimbabwe
1525-1555 12345 Ndebele 49 6025 100 6 3 Zimbabwe
1525-1555 67 English 49 6025 100 6 3 Zimbabwe
1555-1625 1234567 Shona 49 6025 100 6 3 Zimbabwe
1800-1830 1234567 Zulu MW 1170 50 MW ND Swaziland
1830-2155 1234567 English MW 1170 50 MW ND Southern Africa
1545-1615 7 Shangaan 90 3200 50 6 3 S Mozambique
1600-1630 12345 Tshwa 90 3200 50 6 3 S Mozambique
1600-1630 6 Shangaan 90 3200 50 6 3 S Mozambique
1615-1645 7 Tshwa 90 3200 50 6 3 S Mozambique
1630-1645 1 4 Portuguese 90 3200 50 6 3 S Mozambique
1630-1645 23 56 Shangaan 90 3200 50 6 3 S Mozambique
1645-1659 1234567 Ndau 90 3200 50 6 3 S Mozambique
1557-1627 12345 KiRundi 19 15105 100 10B 13 Burundi
1630-1645 1 Amharic 25 11700 100 10B 13 Ethiopia
1630-1645 2 Oromo 25 11700 100 10B 13 Ethiopia
1630-1700 34 Oromo 25 11700 100 10B 13 Ethiopia
1630-1645 56 Kambaata 25 11700 100 10B 13 Ethiopia
1630-1645 7 Dimitsi 25 11700 100 10B 13 Ethiopia
1645-1700 123 Oromo/Borana 25 11700 100 10B 13 Ethiopia
1645-1700 56 Hadiya 25 11700 100 10B 13 Ethiopia
1645-1700 7 Amharic 25 11700 100 10B 13 Ethiopia
1700-1730 123456 Amharic 25 11700 100 10B 13 Ethiopia
1700-1715 7 Amharic 25 11700 100 10B 13 Ethiopia
1730-1800 12345 Oromo 25 11700 100 10B 13 Ethiopia
1802-1847 1234 7 English 31 9500 100 10B 13 East Africa
1802-1902 56 English 31 9500 100 10B 13 East Africa
1847-1902 1234 7 Juba Arabic 31 9500 100 10B 13 East Africa
1700-1745 12345 Swahili 31 9475 100 11 5 East Africa
1700-1815 6 Swahili 31 9475 100 11 5 East Africa
1700-1840 7 Swahili 31 9475 100 11 5 East Africa
1745-2045 1234567 English 90 3200 50 9 233 South Africa
1705-1735 1234567 Yawo 41 7300 100 6 233 Malawi/North Moz
1750-1820 12345 Umbunbu 49 6130 100 1 312 Angola
1820-1835 1234567 Chokwe 49 6130 100 1 312 Angola
1835-1850 1234567 Umbundu 49 6130 100 1 312 Angola
1850-1905 1 Luvale 49 6130 100 1 312 Angola
1850-1905 2345 7 KiKongo 49 6130 100 1 312 Angola
1850-1905 6 Portuguese 49 6130 100 1 312 Angola
1905-1920 12 Portuguese 49 6130 100 1 312 Angola
1905-1920 3 Luchazi 49 6130 100 1 312 Angola
1905-1920 4 Luvale 49 6130 100 1 312 Angola
1905-1920 5 Fiote 49 6130 100 1 312 Angola
1905-1920 6 Lunyaneka 49 6130 100 1 312 Angola
1905-1920 7 Kuanyama 49 6130 100 1 312 Angola
1920-1950 1234567 Portuguese 49 6130 100 1 312 Angola
1950-2005 1234567 Kimbundu 49 6130 100 1 312 Angola
1905-1935 1234567 Lingala 31 9940 100 101 343 D R Congo
1935-1950 1234567 French 31 9940 100 101 343 D R Congo
1950-2005 6 French 31 9940 100 101 343 D R Congo
DAY is the day of the broadcast = 1 is Monday etc. & 7 is Sunday
FREQ is the frequency in kilohertz
MB is the metreband
PWR is the power of the transmitter in kilowatts
AZI is the direction of the antenna
Local times are:
Kenya UTC+3 Ethiopia UTC+3 Somalia UTC+3
Tanzania UTC+3 Sudan UTC+2 Mozambique UTC+2
Angola UTC+1 Zimbabwe UTC+2 DRC UTC+1

Saturday, February 22, 2014

The Band WAS Open! Saturday Night February 22

With a break in the cold weather, the only equipment I found myself behind earlier today was a lawn mower! Fresh oil, new spark plug, cleaned the air filter and it was almost as good as bagging some new DX when the little Briggs & Stratton started on the second pull after a long winter's nap. With the blade set low to scalp the winter rye that has come up and mulch the remaining leaves, it was a bit of a long job.  As usual, it gave me time to think about DX projects while trying not to think about whether the spring crop of St. Augustine grass will fill in the blank spaces were the lawn was dug up for sewer line repairs last year!

After cleaning the mower, putting everything away and contemplating whether to try to buy a new blade or sharpen the old one another time, there was a little while to sit down in front of the radios before dinner.

It was still an hour or so before dark. Local time here in Central Texas was 5:10 PM or 2310 GMT. For no apparent reason, I tuned up first on the 30 meter amateur band.  I didn't even make a WWV sweep, just started in, knowing time would be limited. The ever present RTTY signal was present just inside the lower end of the band, so I knew something would be there.  I ran into a weak signal at 10103 who was working a strong stateside station. The "local" was W3QZ and was almost S-9 on the R-75 and sloper. He turned it back to the other station which had not identified earlier with a "BK" so I still did not know who he was at the turnover. The other guy did ID right away and it was Switzerland, HB9LCW coming in 559 still an hour before sunset.

A small pileup was up about 1, with HK3/AL4Q at the bottom of things coming in at 569 from Colombia.  The only other activity on the band were ARRL anniversary stations W1AW/4  on 10107.3 and W1AW/8 on 10114, both every strong here.

Lets jump up to 20 meters. It's not a contest weekend, so things are not very crowded at all.  In fact, at first, I thought perhaps there was not much going on. K4VV was calling CQ on 14005 at 2321 GMT at 10 DB over S-9.  A couple minutes later I ran across special call station ZZ80AL calling CQ on 14019.3 with a strong (589) but very fluttery signal from Brazil, and W3BEE calling CQ with no takers at 14022.5. Hmm, this was not very promising.

At 2326 ran up on a really strong signal from W1AW/8, another anniversary station, calling CQ and listening up on 14035. Well, let's see whose going after him. Tuned up to 14036.5 and there was a pretty good pile of US stations calling.  But what was that weaker one ending in "WB" I kept hearing after the rumble from the US stations ceased with each round of calling? A surprise reminder that just because a band sounds unexciting, one should not give up on it...Vainly trying to get past the "locals" was ZS6WB from South Africa!

Well, perhaps there will be some morsels here after all! I found ZX7T vainly calling CQ on 14055 with a good but again fluttery signal.  I think this one is an expedition to a lighthouse. Then swung back to the bottom of the band for an upward sweep and at 2336 GMT heard another plaintive CQ on 14014. The signal was up and down from S-5 and I missed the call the first time around. Good one! 9L1A from Sierra Leone!  He must have called CQ ten times with no takers! Was no one going to notice him at all? Finally, not a stateside station, but Panama  HP1A with a thundering signal into Texas called and got him on the first shout. A few more calls then PY2DS noticed him.  By then he was posted on DX Summit and the gates opened.

Another good example of how a quick tune across the band and snap judgment that things aren't worth the time is not a good thing.  Always give it time and turn over all the rocks!

Wondering if the MUF was just low, I ran up to 17 meters.  Another ARRL anniversary station signing W1AW/4 was on 18075.8 and doing some business. A few stations were calling CQDX and VP9/G3ZAY in Bermuda was having a little fun working stations  on 18078.  Tuning into the pile I found JH0HVJ and JA1PNA from Japan, not real strong but certainly readable and an indication the band was open.

Going up to fifteen meters, I found stateside stations very weak including another version of W1AW/4 only S-6 at 0000 GMT as we slipped into the morning of  February 23 on the world's clock.
Things were obviously open to Asia with JA4CYZ with a nice signal on 21011 and R0FA from Asiatic Russia calling CQ with a nice signal on 21020.1.  He soon had a little business going. Things were not quite so good for a couple others I heard calling:  7N1PRD/0 on 21027 and an unidentifiable PY2 calling a little higher whose signal was so mangled by flutter I could not copy it.

The aroma from the kitchen was wafting in and I knew there was not much more time ( there are priorities, after all!) so I made the jump to 12 meters.  One signal, at 0016 GMT in the form of JH0INP calling CQ DX with no takers on 24903.2.  Would ten even be worth trying?  Always look. There were indications these other bands were open but just without a lot of activity.

Just before moving to the most important room of the house to check those aromas, I ran across a fluttery LW1EUD  ( Argentina) calling CQDX on 28005. Again the flutter was heavy enough to make copying the signal difficult despite the fair S-6 signal.  Up a bit at 28008.2 was JI3BFC calling CQDX with an easily readable signal.  Time for one more check at the bottom of the band and a prize was found with DS2XUM on 28003.1.  The DS prefix is an alternate for South Korea. 

Not bad for a little over an hour as the sun was nearing setting time.  The bands did not show the real enhancement from solar activity we saw the two weekends before,  but there was also not the contest activity to spur things on, either.  ( I wonder if anyone has done any real studies on the effects on the ionosphere of all those signals that appear on the big contest weekends)

A repeat lesson here for those times when the bands do not appear open.  There just might be something lurking there.  Spend a little time digging.  If you are a ham, calling CQ might be a good thing.  You might be howling at the moon, but then, you never know who else might be out there tuning wondering if the bands were truly dead.  If everyone listens and no one calls we don't get anywhere ( if a tree falls in the forest and no one is there ...well you know the rest of that one!) If you're an SWL, don't just make a quick pass and give it up.  Tune slowly and carefully, please.( a variation on a reminder from the guy playing music at the skating rink many years ago from days of my youth!)

Well, gotta go.  There are fresh chocolate brownies coming out of the oven! ( like I said, there ARE priorities!)

Monday, February 17, 2014

Hearing the Band Open

Often when we sit down in front of the radio, things are already going. We tune to a band looking for something particular or to just search, but usually knowing of feeling that prop is there for something to look for.

It is another thing altogether when one goes to a band waiting for something to happen. Occasionally we can almost hear the door open and the signals come rushing in like the guests to a party or students coming into a room when class starts.

Such was the case this past weekend ( February 15th and 16th GMT 2014) as I tuned the low bands in the ARRL DX contest. I had planned to cruise the lower two bands because of commitments during the day that would preclude a full out effort. The targets would be 80 and 160 meters.

I have learned that these two bands, unlike 40 and 30 meters and the 60 and 49 meter shortwave broadcast bands, do not show much life before sundown. The latter bands often will show long haul activity while the sun is still up, but 80 and particularly 160 meters must “wait” until D-layer absorption begins to drift away. Often short skip will occur early ( first hop stuff out to 1500 miles or so) and even will occur in the standard AM broadcast band. In fact, as I have previously mentioned, I use listening on that band as a  precursor to hunting on the lower shortwave bands and as a sort of barometer for how things will be.

Friday night ( Texas time, Saturday morning GMT) I waited till about 8 pm local before tuning in on 80 meters. The broadcast band had not been particularly hot on the way in from work and I also had read on Space Weather that there was the possibility of some solar activity affecting things, so was almost concerned that the low bands would take a hit as far as conditions anyway.

It was about 0215 GMT when I sat in front of the R-75 as the receiver of choice for the evening. Starting at 3500 and moving up, I heard as expected, mostly Stateside stations coming in. In this particular contest, DX stations work US and Canadians. The “ usual suspects” were down at the bottom of the band calling CQ with very strong signals. Even with one preamp turned off, most were swell above S-9. The band was dominated by stations from the Northeastern US and Eastern Canada. VA2WA was particularly strong on 3503 at 0222 GMT. Though I heard several stations working OE2S from Austria  on 3506 at 0231, he was very weak and I could not firmly pull out his callsign. I heard the first Caribbean station in the form of CO3IT from Cuba on 3510 at 0234. Were the Europeans going to make it this evening at all?
Up the band a bit I heard stations working HG1T from Hungary, usually a powerhouse station during these contests. He was on 3510, but way down in the grass and barely readable here. Another Hungarian, HA5PI was on 3512 at 0244, but again very weak and taking several cycles through his callsign to firmly identify him.

Going on up the band, there was another Cuban CO2JD very strong, and PJ2T pounding in from the Caribbean, but the powerhouse Europeans were just not powering! Over the next half hour, several of the “regulars” began to come in with marginal signals. There was 9A1CY on 3514 at 0253 barely readable, usually powerful contest station YT3A from Serbia at 0255 on 3515.7 by himself on the frequency holding forth with new England stations, but listed as only 539 in the log here. As I went up the band, a few more came in but it was a struggle. ON4IA from Belgium at 0257 on 3516.5 at 549, F5CQ from France on 3519 at 0301 that took a couple minutes and several contacts by him to identify. And signals were up and down, up and down.
By 0330, I had logged about a dozen stations, but all were in the grass. LZ9W from Bulgaria at 0330 on 3531 which usually pounds into Central Texas was easily readable, but just not very strong. But that was when the door began to open. In fact, as I was listening to him work station after station, I could hear him start to come up, almost as if the great cosmic RF gain control was being rotated. Over about a five minute period, his signal was up to S-8 and holding steady. Over the next few minutes several others were logged, including CN2AA from Morocco on 3521 that I had missed completely on the first pass. The log began to fill up with calls like CR3L, LX9DX, OK5D, SK3W, 9A1A( very strong!) OM3RM, OL7M, SP3GEM, IR1Y. Now this was more like it! The band in minutes had gone from stations being barely readable to a crowd appearing. You could almost hear the rush of the door opening!

It was time to try 160. It was almost a repeat of the same story. At first, only Northeastern US stations and Canadians were strong, the lower band showing real life a bit behind the higher frequency 80 meter band. VA2WA was present ( obviously a multi-op contest entry!) on 1825 at 0341 GMT with an astounding signal. It was already starting to happen as I listened. The Caribbeans were already quite strong in the form of P40L from Aruba on 1827, KP2B from the Virgin Islands next door at 1826.3 ( love those dual 250 Hz filters!!) PJ2T on 1829.5, ZF3A on 1830, KP2M on 1832, HK1MW from Colombia on 1821.5, KP4KE from Puerto Rico on 1831, V31TP from Belize on 1812 All were gaining strength before my ears!

But where were the Europeans? It wasn't that long ago that hearing them at all had been a treat for me, and now I was expecting them to prop in easily ( see where our threshold of expectations shifts with time!!) But not to be disappointed, an old friend showed up first with 9A1A, another multi op, multi transmitter contest operation, found beneath a pile of hungry US stations on 1818.4. Then CR3A was found on 1826 and Morocco jumped into the log with CN2AA showing up with a very nice signal on 1832.3 at 0423. The band could be officially declared open!

I have always marveled at how the lower bands open up. Somewhere there is probably published material that tells how the various layers of the ionosphere work, as far as how long it takes for them to disassociate when the sun goes down and how deep each frequency will penetrate before being totally absorbed as it happens. I often wonder if the higher layers remain ionized more with the sun still over the horizon for us on the ground, but perhaps still “visible” to the molecules of the upper atmosphere. Does the angle of the radiation striking them have anything to do with it?

I am reminded of an instance when I was in East Africa in the early 70's ( 1972 or '73) on the occasion of a total eclipse of the sun. I was working in the newsroom of the American Forces Radio and Television Service in Asmara, Ethiopia ( now Eritrea) in early afternoon as the eclipse began. We had several R-390 receivers in a rack used for receiving audio feeds via HF and for tuning in radioteletype signals from news services. There were three receivers in one of the equipment racks and only two were in use at the time. While sorting through news copy for the next broadcast, I tuned one of the receivers to the 60 meter frequency of a broadcast station in Djibouti that was usually just barely listenable in Asmara during the day and left it there as the eclipse progressed. It was amazing to see the signal come up from about a third scale to almost full scale over about a half hour period as we neared totality. I wish I had had the opportunity to tune through the bands and listen for other signals on the amateur bands or other shortwave broadcast frequencies during the eclipse, but duties would not allow it. There was just not the time. But it was amazing to see the band open and close in less than an hour due to the artificial night of the eclipse. I would guess that the lower frequencies might not have been affected as much as the D layer might not have had time to disassociate enough. If anyone has the opportunity to make such an observation during a solar eclipse, drop a note to the “ comments” section of this blog with email contact information and I would love to hear about it, and maybe include it in a future post.

There are many things to marvel at as we tune the bands. Sometimes we don't notice them in the rush to log stations or hunt for the next catch, but sometimes it is very interesting and enlightening to watch the “ mechanism” by which things happen. Gaining this knowledge while making the loggings will also surely help in understanding how prop works and in making it work for us in future DX hunts!

Sunday, February 9, 2014

Auroral Effects on Low Bands, Feb 8 and 9, 2014

DX on the low bands appears to have been impacted by auroral activity this weekend ( Feb 8-9 GMT 2014). While first hop skip in the lower latitudes resulted in usual very strong signals here in Central Texas, higher latitude stuff or signals that had paths through the higher latitudes but not normally affected by aurora were bothered.

I started by listening on the low bands Saturday morning February 8 Texas time ( 1100 GMT), hoping to hear some of the Japanese stations during their 160 meter contest, but heard nothing. There were very few signals at all and all from the Northeast US or Canada were very weak. Not much on 80 though there was some DX on 40.

During the day, the high bands showed good activity though signals were not exceptionally strong. US stations had some echo on them. Ten meters was open to Europe already right at sunrise. Amsterdam Island was in on 15 meters, though not strong.
The Dutch PACC contest was on and signals were all over the CW portions from there on the high bands including ten meters. Saturday night local ( Sunday morning GMT 0000-0200) showed not much happening on the low bands. Heard none of the PA stations in the contest at all on 160 and only a few US stations working a few. US stations were weaker than usual. On 80 meters, PA stations and Europe in general was below par signal strength wise. Many stations had a characteristic echo effect or lots of polar flutter, even signals that would travel lower latitude paths. Forty was a little better, but not much.  Sunday morning I checked  the Space Weather sites and saw that there was a big Coronal Mass Ejection on Thursday and that the Earth's magnetic field was shaken up a bit. Auroras did extend well south of their usual boundaries.

Here is how it went. At 1149 the only signal heard on 160 meters was AA1K calling CQ on 1820.6. Tuning up and down the band turned up nothing else. DX Summit did not show much, either.

Making my WWV run at 1152 I found this:

1152 2500 kHz WWV S-9+20 DB. No trace of WWVH
1153 5000 kHz WWV S-9+30 DB. WWVH just audible beneath
1154 10000 kHz WWV overridden by WWVH. Together they peaked at S-9 with very rapid QSB and flutter, maybe some echo. JJY unusually heard beneath.

Tuning 40 meters, things were pretty bleak. A lot of stateside stations were calling CQ DX with few if any takers. At 1210 GMT I heard UA0C on 7010 very weak. A few minutes later heard a JA1 but did not copy the entire call. Midwest and Northeast US stations were not their usual strength, though CO7EH from Camaguey, Cuba was a good S-9+ on 7011 at 1217 GMT. The Florida stations appeared normal signal strengths so it appeared signals from higher latitudes or passing through them were weaker or “ flutterized”.

A run up to 20 meters showed activity picking up because of the PACC ( Dutch) contest, though signals were not strong. There were a lot of Russian stations early with many of the Dutch stations participating in the contest weak and fluttery or with echo. Now this might have been due to them having directive beam antennas pointed toward Central or Eastern Europe to pickup strong first hop stuff, but then again, maybe not. The first heard was R1TV at 1303 on 14007 weak and fluttery with a 539 signal. I found PA7LV working a string on 14022 beginning at 1304. He was only about S-5 here with QSB. I heard in quick succession RW3XM, RA2FN,and RV3MJO working him, all with weak signals S-5 or less. The next few minutes saw several more Russians and an SM5 from Sweden in the log, but few signals from Southern Europe.

Interestingly, in the midst of all this, I found FT5ZM, the expedition on Amsterdam Island at 1318 on 14023 with a fair signal but not working much.

A jump up to 15 meters saw it open fairly early for here. At 1319 I heard PI4CC on 21007 working a string of stations fairly close to him. Among them were HB9CIC, LZ1ND and YO9HG, and one in the string that I am not sure of the location: RA0LQ maritime mobile. European stations gained in strength rapidly over the next little while and the noise was very low.

A little later in the morning after a break for breakfast and chores a check showed European signals very strong beginning about 1630 GMT, with US stations weak and fluttery with lots of echo. At 1636 a bit of a surprise with FT5ZM showing up on 21023 with a steady, albeit not very strong signal. Most strong signals from Europe were from the Central part of the continent. On 12 and 10 meters, there were many, many European stations coming in, though not with overwhelming strength.

This was the case most of the day through mid afternoon. The higher frequencies appeared to be enhanced somewhat by whatever solar activity there was. At 2109 W1AW/KH6 from Hawaii was heard on 28032.6 with a signal that reached a solid S-9 at times.

Whatever effects were wrought on the low bands were still in place Saturday evening, Sunday morning GMT. At 0121 K1GQ was only coming in 559 on 1822 and W9UK was just barely audible on 1811.8 at 0131. There were no Europeans at all coming in on 160, no sign of any Dutch signals in the PACC contest

Checking 80 meters, PI4DX which had huge signals on the higher bands earlier in the day wa only in at 569 on 3521 at 0140. PI4AX at 0143 was 559 on 3517 with rapid fading. One other signal of note was PI4COM heard on 3519.7 at 0145, but not very strong. Other European signals were just not standing out from the crowd. Those that were there exhibited a lot of rapid QSB that normally I am used to hearing on the higher bands.

A check of 40 meters showed higher latitude US stations lower in strength from normal and lower latitude signals strong and dominant. Russian signals were weak and fluttery. Most Dutch stations in the PACC were below par in strength with the exception of PI4DX who was 589 on 7016.8.
Equipment used for these observations were the Icom R-75 with assistance from the old, trusty Hammurland HQ-170 backing it up on 160 meters. The antenna was the sloper at 40 feet.

All of this falls in line with what I have noticed in the past during auroral activity that extends south of the usual areas. Observations of others during this period would be welcome to the “comments” section of this blog. If there is a lengthy observation you would like to share, include your e-mail address and I will send you mine. Your e-mail address will not show up on the blog. All comments are reviewed before posting. In fact, I am always interested in observations of others who might like to share them either with me or for posting here.

The one other observation from this weekend is that after over fifty years of tuning the bands there are still fun things to observe and always more to learn. Everything posted here is not represented as scientific fact, but rather as events as observed.

Wednesday, February 5, 2014

Flashback: Learning About TV DX

Can you imagine a world without cable or satellite TV? A world where there might be only one, two or three local stations to watch and no "specialized" movie or sports channels even in existence? Travel with us now to those thrilling days of yesteryear filled with analog, black and white television.
It was in the very early sixties.  I was still in my pre teen DX-in nyears, tuning the broadcast and shortwave bands with a table top Watterson BCB set and a little National SW-54 VERY basic general coverage receiver. And spending most summer days at my grandmother's house watching tv and enjoying all manner of good food, including home made kolaches.

But one day I made an accidental discovery that brought a whole new dimension to my young years of DX-ing and filled a very exciting summer.

Even during the time I was chasing DX on the standard broadcast band and shortwave, it never crossed my mind that TV was for anything other than entertainment. I mean, I had seen a column on TV DX in Radio-Electronics magazine. But we had such trouble getting to watch TV stations from Dallas about 90 miles away, and the idea of actually receiving signals from great distances just seemed like something that happened only under very freakish conditions.

At my folks house we had been satisfied watching two local channels with rabbit ear antennas. I had put up a ten element high band VHF yagi on a twenty foot mast that had been our only lifeline to tv during our short time living in West Texas. We had lived in Coleman with the only station available for viewing being KRBC on Channel 9 from Abilene, about sixty miles from our house.

When we moved back to Waco and while my dad was building our house, the antenna was folded up and lay on the ground with its mast. But as a kid wanting to watch more TV than just on the two networks available on the two local channels we had ( there was no such thing as cable TV in our area then) I was always trying to figure out a way to get more channels. Channel 4 from Dallas would sometimes come in with a snowy picture on the rabbit ears. Channel 8 was more difficult. It always seemed that the “good “ shows were on those channels and not on our local two. Channel 11 was the real prize because it was an independent station in Ft Worth that carried old movies. Even if it would have been strong enough to give even a snowy picture, our local channel 10 would have covered it up with the almost non-directive rabbit ears.

With my dad's help, I got the twenty foot mast up beside the back of the house with the 10 element single channel yagi on top. It gave a watchable picture on channel 8 and in the evenings a decent picture on channel 11. In addition to the greater signal strength due to the gain of the antenna, the directivity helped to knock down the overwhelming strength of the local channel 10 which was almost directly off the side of the antenna. That summer, our local channel 10 also moved its transmitter site from its relatively short downtown tower about ten miles from our house to a taller, 1000 foot tower that was almost 25 miles away. Even with the greater height, it was not so overwhelmingly strong.

I can't even remember where it came from, but that summer I also came up with a three element low band yagi.  I may have traded something to a friend for it. I really don't remember. But it went up on the mast as well. It did not really have enough gain to give fully reliable pictures on Channel 4 from Dallas, but in the evenings it was watchable with some graininess.

My grandparents lived about a mile down the street from us. They had an outdoor antenna on their roof, probably thirty feet or so above the ground. I never really understood it, but even though they were down the hill from us, they always got better TV reception than we did. In fact, they got all the Dallas stations just fine, 4 and 8 were good all the time and 5 and 11 from Ft Worth were also very watchable. The antenna was a very simple single bay conical. This was the most basic of antennas. At a time when every house in town had a telescoping mast with varying amounts of educated aluminum tubing on top, it was fairly small in comparison to most. But it performed very well.

For that reason, in the summers, my sister and I would often spend the day with them while my folks worked. ( Well, OK, they were technically baby sitting ). There were days that I could ride my bicycle back up to our house for an hour or two of listening to the radio, but meals, TV and a good supply of home made Czech kolaches kept us close to Grandma's house a good bit of the time.

It was on a late morning in June that my new DX challenge came into being. The Channel 8 morning movie was over and I had begun switching channels around looking for something else to watch. Channel 10 had a quiz show, channel 11 was in the middle of a movie that didn't look too good, so I continued on around the dial, planning to work my way around to channel 4. This was in the day of “detent” tuners. The channel knob had  a hard stop for each channel, manually tuned. There were no remote controls in those days. There were no digital numbers to punch it to change channels. One had to actually turn the “ channel changer” around to another of the 12 channels. Ka-chunk, ka-chunk, ka-chunk. I went around. Nothing on 12 and 13, nothing on the UHF slot ( another story about that! UHF channels were in those days tuned on a separate dial. To get them, you tuned the main channel knob to the “UHF” position, then tuned in the station on channels 14-83 on a separate dial –it did go up to channel 83, then, before those frequencies were snagged for cell phone use...none of them then either--. Once you got a UHF station tuned in, you could access it with the main dial, just by going back to the “UHF” position. Clear?)

As I was saying, I passed the UHF slot and of course found nothing because there were NO UHF stations anywhere near our area then. Our local channel 34-KANG had gone dark some years before. But as I hit channel 2 expecting nothing to be there-Surprise! An almost perfect picture appeared. What was this? At times the picture took a roll, sometimes there were vertical bars that rolled sideways through the picture. Sometimes snow would pulsate through the picture or the audio would develop a whine almost like a fluttery heterodyne.

But where had this signal come from? I knew from looking at the TV channel lists in Whites Radio Log that the closest channel 2 was in Houston, almost 180 miles away and almost exactly off the back of the antenna. Waiting patiently, I watched part of some old sit com rerun hoping to get a clue from commercials or maybe an ID slide. I had already gone into the DX-er mode.

It seemed like a long time, but in reality was only a few minutes until the bottom of the hour and time for a station identification. While in the DX-er mode, I was already expecting the station to take one of its signal dips or flashes of snow just at the critical time of the identification. But DX-er's luck was with me. What a surprise it was when the ID slide popped up! It was KDIX in Dickenson, North Dakota! North Dakota! I had not even logged North Dakota on the standard broadcast band in several years of tuning around!

The ID came just in time, as both horizontal and vertical bars began rolling through the picture and the snow began coming in waves. The station was soon lost in the noise.

I quickly ker-chunked the channel knob up to channel 3 to see if there was anything there. There were traces of something, but it was obscured by rolling pictures, rolling bars and the sound was a scream of FM heterodynes ( sound in analog TV was frequency modulated while the picture was amplitude modulated). I figured there were either multiple stations coming in and QRM-ing each other or I had missed the opening.

Going up to channels 4 and 5, and not expecting much because the Dallas and Ft. Worth stations were relatively strong, I was surprised to see signs of strong interference. Both stations showed tearing of the picture at the corners and horizontal bars rolling through the picture. Even the local channel 6 whose transmitter was perhaps 30 miles away was showing some wiggling and signs of faint bars.

After lunch I got permission to go up the folks house and got out my stack of Radio-Electronics magazines. I had almost a dozen going back a couple years. Not every copy had the TVDX column, but enough of them did that I got a good idea as to what was going on. It was Sporadic E propagation. This is the reflection off relatively small ( small compared to the entire ionosphere at least) highly ionized clouds inside the ionosphere's E-layer of lower VHF frequency signals. At that time there was no real theory as to what causes the formation of the clouds. Even today, that is somewhat open to question. What is not open to question is the fact that it happens, often in late spring and early summer, but sometimes in other parts of the year. Sometimes only the lower channels would be affected, but sometimes under highly intense ionization, frequencies as high as the FM broadcast band could be bounced back to earth up to a thousand miles away.

Even though I had seen the signal drop out from the North Dakota station earlier, thought I would try at the home place to see if something else might be coming in. I got the idea of turning my little three element antenna sideways away from Dallas to minimize the signal coming in from there and maybe see something on channels 4 and 5.

The antenna ended up pointed just about due east and though channels 4 and 5 were pretty well nulled out, there did not seem to be anything there. However on Channel 2, there appeared to be two signals battling it out. The audio sounded like bees buzzing at times and the vertical bars were rolling furiously horizontally across the screen as first one station, then the other took over and came through. At about three o clock ID time came around and beginner's TV DX-ers luck really took hold and I was able to identify both stations as one faded down and the other alternatively faded up...there were two Florida stations, WESH-TV from Daytona Beach and WTHS from Miami. I am not sure if those same call letters belong to those stations fifty years later, but I did get a QSL verifying reception of WESH-TV.

After a half hour battle between the two stations on channel 2, I finally got to look up on channel 3, and quickly identified WEDU from Tampa just as signals started dropping out.I turned the antenna back around to the north to be ready for an evening's TV watching from the Dallas stations and when I went back into the house ( the antenna was turned by the “armstrong method”, rotating the entire mast by hand) I was surprised to see a new station coming in on channel 3 where I had left the was identified moments later as WKZO from Kalamazoo, Michigan. It soon faded away and continued checking of the low channels turned up nothing more the remainder of the afternoon. But all in all, it was a pretty exciting day for a first look at TVDX!

Over the next few days I read a lot and learned a lot about VHF wave propagation. That learning process was to extend over the next fifty or so years, and continues on today. The same goes for any form of DX. One learns the ins and outs of the conditions that bring it about and while not necessarily understanding the physics of the situation, one can at least learn to recognize them when they come up and take advantage of them to get things in the log. But then, isn't that the aim, anyway?

The next morning was one of the first in a long time that I did not head for the shortwave receiver. Instead, even as my dad was getting ready for work just after sunrise, I was in at the TV, looking for signs of distant stations. The low channels were dead empty except for the local channels. The Dallas channels were particularly snow free, looking better than usual. Hand rotating the antenna around to the southeast, I noticed the station in Bryan, about 90 miles away, KBTX on channel three was coming in for the first time. This channel in the early sixties was not a full power VHF but relatively low powered and on a short tower. It served mostly as a relay or “satellite” station to our local channel 10, KWTX, only originating a few of its own local news segments. They were even identified together.

On this same antenna heading was a weak channel 2, but it did not have the same appearance as the Sporadic E skipped channels of the day before. It was the station I had suspected when I first saw a signal on channel 2 at my grandparents. It was KPRC in Houston. It had the appearance of a weak, distant regularly propagated signal. The fading was very slow and deep, never really quite coming up to regular viewing appearance, but without interfering bars. There was no interference to channel 4 which was still strong even off the back of the antenna.

Channel 5 showed a little barring or herringbone effect, but it took turning the antenna around to the southwest to get a recognizeable picture. That turned out to be KENS in San Antonio. Houston was 180 miles, San Antonio a little less. From what I had read about sporadic E, this was way too short a distance. I had checked all the other channels up through the high band of VHF and nothing was showing. I had hoped for a signal out of Houston on their other channels, but it was not happening that morning.

One thing to note about VHF TV channels. They were actually divided into two bands, high and low. The low group consisted of channels 2-6 and run from 54-88 mc, each channel 6 mc wide. You will notice that the numbers don't really add up. That's because there is an additional gap between channels 4 and 5. That gap is the home for some aviation navigational aids. These are where the marker beacons on approaches to runways are located. It also allows local allocation of channels 4 and 5 in the same city. Other channels require a channel wide gap to avoid adjacent channel interference. Directly above channel 6 was where the FM broadcast band was located, from 88-108 mc. There was another gap, with channels 7-13 being located between 174 and 216 mc. Those channels are known as “high-band VHF” and channels 2-6 are known as “ low-band VHF”.

In the analog days, the picture carrier signal was at the low end of the channel with the lower sideband of the amplitude modulated carrier attenuated with a filter. This created a signal known as “vestigial sideband”. The receiver could detect the picture information with the carrier and only the upper sideband. This conserved spectrum space.

The audio signal was a separate frequency modulated affair. In fact it was generated by a separate transmitter altogether. It was located 4.5 mc above the bottom of the channel. This explained why on FM receivers, one could often hear the channel 6 sound. The sound carrier was just below the FM broadcast band and still within the range of most FM receivers. The separate sound and picture transmitter outputs were fed to the same antenna through a diplexer. There was also a filter to reduce the strength of the lower sideband, to obtain the “vestigial” sideband operation. This meant in TV transmitter rooms you could see considerable piping in the ceiling as these filters and the diplexer were often hung above the transmitters.

What I began to learn as I turned back through the pages of the old TV DX columns and through the previously unread VHF portions of the Radio Amateurs Handbook was that there were several mechanisms for VHF and UHF signals to travel long distances. Some involved the E layer with Sporadic E, some rarely involved the F Layer just like regular short wave ( though this was very rare) and some involved things happening in the lower levels of the atmosphere as a result of weather.

It was interesting to note this morning and subsequent mornings that this particular method had to do with changing temperature. The previous night had been cold. During the morning, it was warming rapidly.

The air is not warmed directly by the sun. Our own local star sends out radiant energy which just passes through the air. The sun warms the earth, and the earth warms the air through conduction and convection. Thus sometimes in the mornings there can be a layer of warm air at the surface, with cold air above it. When a VHF signal passes through this boundary, it appears to be bent slightly, bending back toward the earth and thus following its curvature more than it normally would. As this layer thickens and the boundary layer rises, it appears that the distances covered by the bent signal increases, until a critical angle is reached when the bent signal no longer returns to the earth.

That matched what I began to notice over the years. This morning “enhancement” would occur not right at sunrise, but a little after, peaking an hour or so later, depending on the actual temperature difference between day and night. Then it would just disappear.

That particular morning I decided to try to search in a different direction, going around to the east. Over the years I found that openings tended toward the east. I do not know if this is because the sun has risen just a bit earlier in that direction and the heating is a little more advanced or what. It's not a scientific thing at all, just something I have noticed over the years.

That morning I also learned even more about minimizing local signals. As I turned the antenna to the east, it put the ten element yagi's side toward our local channel ten. Sometimes the front to side ratio of long yagi antennas can be quite good, and on this particular morning it was good enough. A signal appeared interfering with the local channel 10. There were the tell tale horizontal bars rolling through the picture and the sound was garbled with two fm signals obviously beating against one another. After a few trips outside to make minor adjustments to the antenna direction, the interloper signal gained the upper hand long enough to be identified as KLFY in Lafayette, Louisiana. This was my first high band VHF TV DX catch.

There were no sporadic E signals that morning and in about another half hour, all the “enhancement” of ground wave signals was gone. Looking back, I am guessing that this bit of DX was the result of just such a temperature inversion. It was a mechanism that would provide lots of fun over the coming years not only with TV DX but amateur radio DX on the 2 meter band.

Later on day 2 of my TV DX career I was somewhat disappointed in the beginning. At my grandparent's house with the conical antenna, there was only one signal that came through from the north. Just before noon there was a good signal for just a little while from WLWD in Dayton, Ohio on Channel 2. It was quite stable and watchable for about a half hour, then quickly dropped into the snow. There were indications of other stations, but none strong enough to watch.

After lunch that afternoon, I went back to the other house and once again tried nulling the Dallas stations ( the grandparent's antenna was not rotatable) This time I got lucky. A station popped up and completely covered the Dallas Channel 4 ( at that time the Dallas 4 was KRLD-TV). It turned out to be a station that I would see many, many times during sporadic E openings. It was WUNC in Chapel Hill, North Carolina. I don't really know why it appeared so often. Perhaps it was in just the right place and the E clouds formed repeatedly in the right place or what, but it was visible many times that summer and in subsequent years.

That same afternoon, another North Carolina station got in the log. It was WFMY-TV in Greensboro, North Carolina.

A pattern began to show up. There would be sporadic E openings to the north or northeast in the mornings and toward the east in the afternoons. That next morning at the grandparent's house signals came in from KDLO on Channel 3 from Florence, South Dakota, from WGR-TV on Channel 2 from Buffalo, new York, from KID-TV in Idaho Falls, Idaho ( there had actually been a picture of the ID slide from that one in one of the magazine articles I had read), from WBBM-TV in Chicago and rounded out by WBAY on Channel 2 from Green Bay, Wisconsin. The log notes indicate that on that morning, signals were up and down with at times three stations swapping top position on a given channel. There were others that were just never identified. Some were identified by actual ID slide and others by locations mentioned in local commercials and checked against the venerable White's Radio Log listings.

One thing I noticed while rotating antennas over the years when pulling in Sporadic E signals, even with bigger antennas in later times with much sharper directional patterns than the small yagi I was using for Low Band VHF that summer, was that the incoming Sporadic E signals did not peak sharply in direction. I kind of wonder if this might indicate that they were coming in at a rather high angle and perhaps striking more the top of the antenna than the front. Again, this is not a scientific thing, just an observational thing. This was a very useful trait in a way, because the nulls on the sides of the antennas were always sharper and it was often possible to null out a near local station enough to pull in the incoming DX signal, even if the antenna was not really pointed in the optimal direction for the distant station. As is often the case when using a loop for Broadcast band DX, it is sometimes more important to get rid of the interfering station than it is to get a perfect peak on the incoming signal of your target.

The next few days were a little disappointing. While there were some openings, the were shorter and not as intense. I was also seeing some of the same stations I already had in the log. There were a few more early morning high band loggings as a result of some morning enhancement or temperature inversions...KTBC Channel 7 from Austin which was a fair catch because in those days they were on a short tower, and KTRK Channel 13 in Houston. I particularly remember them because they were not running a simple ID slide. They had a short animated ID that had a cat like creature that marched onto the screen and did a kind of roar with the “KTRK”being its teeth!

That next weekend saw an opening that made up for the slow Thursday and Friday. It was Sunday after lunch and with the family all home, it would probably not have been a good time to commandeer the TV for Dxing. However, the skip was so strong that even with the antennas pointed toward Dallas, Channels 4 and 5 were so hit with distant station interference as to be be completely unwatchable. Even the local Channel 6 had synch bars rolling through it.

This kind of caught my dad's attention and he listened as I told him about my adventures during the week. We rotated the antenna around a bit to see what we could see. The strongest signal I had yet seen from anywhere popped up on Channel 2 with the antenna pointed west. It was KNXT from Los Angeles, California. It was strong and stable, just like watching the Dallas stations on a normal day. It was in like that for almost two hours. A check up and down the dial found a similar situation on Channel 5, with KTLA from the same city also blistering in well for a couple of hours. These signals were rock solid, with little flutter, fading or glitches. It was amazing. And this on a three element antenna only up twenty feet above the ground!

This was something else that would be confirmed over the years. While antenna height is very important for “regular” tropospheric reception and for temperature inversion reception, it is not necessarily so for Sporadic E. Since the signals seem to be coming down at a relatively steep angle, a lot of height might not be necessary to get the signals. As long as the antenna is fairly well in the clear and not totally hemmed in by trees and buildings, the signals will get there! High antenna gain is not really necessary either, as I have notice unbelieveably strong signals from TV and FM stations and even amateur radio stations on 6 meters that come in by Sporadic E. I'm not saying that bigger, higher gain antennas and greater heights won't get you more stations or a shot at the weaker ones, but its not necessary to at least get in the game.

That same day the pattern was broken in another way. It was mid afternoon when KYW, Channel 3, from Cleveland, Ohio came bouncing in along with KTWO, Channel 2, from Casper, Wyoming ( another place I had not yet logged even on the radio!)

That afternoon was marked by another milestone: my first “foreign” TV DX as late that afternoon when the other strong signals had all faded into the snow, a new one appeared. It was eventually identified as XHFM-TV from Vera Cruz, Mexico. That was somewhat strange because there were not even signs of any other Mexican stations and the antenna was pointed almost east. I don't know if this is an example or not, but there have been times I have wondered if a signal did not arrive by scattering or dual hop bouncing between first one E cloud, then the ground or sea water and up to another E cloud. Over the years there have been some real “dog-leg” antenna headings for some signals.

The next week, I decided to try to get the antenna a little higher to “see over” some of the young trees in the back yard. I found a large piece of water pipe with a coupling in it and put another piece of pipe past the coupling. It fit inside the bottom of the twenty foot push-up mast I was using. In addition to getting the top antenna about eight feet higher, it also allowed me to get more separation between the high band and low band yagis.

I don't know if that is what did it or if the conditions were just better, but that week, my station totals for high band DX by morning enhancement took a big jump. After the first group of stations came in, it also got me watching the weather on TV and the weather maps in the paper more closely.

That Tuesday morning, by carefully nulling the local Channel 10, I pulled in KZTV on Channel 10 from Corpus Christi. The elusive high band VHF's from Houston came in as KHOU, Channel 11 and KUHT Channel 8, the educational channel showed up. KTRK Channel 13 returned with good signals.

While pointed in that direction a check of the low channels brought a surprise with the appearance of KPAC, Channel 4 from Port Arthur enough above KRLD Dallas for at least an ID.

Turning back to the north, KXII Channel 12 from Ardmore, Oklahoma made an appearance, along with KWTV Channel 9 from Oklahoma City. Watching the weather on KWTV I noticed them talking about a strong front that had passed them that would be triggering thunderstorms along the Texas-Oklahoma border later in the day.

That got me to thinking about the bending that occurs at the boundaries between warm and cool air during temperature inversions and was the first clue to me that frontal boundaries could provide enhanced travel for VHF and maybe UHF signals. Over the years I have noticed from observation that they indeed appear to do just that. It has been my observation over almost fifty years of trying to pay attention that signals crossing a frontal boundary at a near right angle to the boundary appear to get the most enhancement. Those crossing at shallower angles also seem to get some help, but not as much. It also seems that sometimes the path gets bent a little horizontally, with signals crossing the boundary sometimes appearing to come from a slightly different beam heading than you might expect.

Anyway, on that day, it seemed logical as I had not seen those signals before while looking north. The next day when the front had passed and brought rain to north Texas, the signals were not there to be seen.

I had a chance to test the idea a few days later when what was described as a cold front was approaching from the north and west. The next morning I had the ten element antenna pointing north west and swinging to the west at times ( I was beginning to wear out the back screen door going out to turn the antenna and wishing for an electric antenna rotor by this time!) Sure enough, KRBC Channel 9 from Abilene ( ironically the station for which the antenna was purchased to receive in the first place when we had lived in Coleman) came in well, along with KOSA, Channel 7 from Odessa in West Texas, a pretty long haul! After the front passed, the next day, they were gone, but to the east, KTRE Channel 9 from Lufkin was in as was KTBS Channel 3 from Shreveport.

That week had not been as spectacular as the first week of Sporadic E DX but had been pretty important for another reason. I was learning some valuable things about VHF signal paths that would be very useful in the future. It also got me in the habit of keeping a small notebook for things that appeared to affect the signals. It created a habit of learning that has lasted almost fifty years.

I noticed something else interesting that day. It had been a full two weeks since I had even turned on the SW54 shortwave receiver! It would thus mark another landmark in my DX-ing career: finding different aspects of the hobby to study and spend time with. That pattern would repeat itself through the rest of my life. The focus would change from time to time, then return to previous interests, keeping the hobby fresh and new over the years.

The next weekend was another firecracker. There was a huge opening with what must have been multiple E layer clouds. It was earlier in the morning than usual for Sporadic E openings as I had observed them over my huge, two-week career of TV DX-ing. That Saturday morning about 9 o'clock, I logged my first Canadian as CBWT from Winnipeg came roaring in on Channel 3. It did fit the pattern in one way. The first signals to appear had come from the north or northwest. However, it was not alone as several stations were fighting for supremacy on the channel. Over the next hour and a half, XEZ ( absolutely certain of the call letters because they were very visible three or four times) from Mexico came in ( not certain of the city, it did not appear in my White's Radio Log) but the biggie was CMKJ from Cuba. All were on channel 3 and all were logged within a short period of time. Later, KTVK from Phoenix came in on the same Channel 3 along with KPHO on Channel 5, also from Phoenix. What a day! It was a good thing it all happened in that short period because the family for some reason wanted control of the TV that afternoon. Imagine that!

It had become apparent that the propagation of VHF television signals were nothing at all like that of short wave signals. But to summarize what I had learned in the first couple of weeks work and reading: Clouds that formed in the E layer were small and localized. There appeared to be no real short skip. There also appeared to be times that there might be two hops between different clouds. The one other thing that seemed apparent was that the clouds did not move much. Stations seldom came and went with regard to distance, but as the clouds disassociated, the signals either dropped out or signals bouncing from other clouds would replace them. It appeared that at mid-day the signals tended to come from the north, then after noon till mid-afternoon would come from the east. But this was not a hard and fast rule either. Sometimes there would be openings to the west and no where else. I had not seen many openings to the south, having seen only a couple Mexican stations. I had seen only a little of the second form of DX that affected the high band VHF channels through morning temperature inversions or frontal passages. I had seen nothing on UHF, having no antennas at all for that band.

I had already been a close observer of TV antennas for several years. I had always been looking for ways to get the more distant stations for entertainment purposes while our family did not have either the cash or see the need for buying antennas. I had watched roof tops and tower tops to note what kinds of antennas people in the area were using. Many had been up since the early fifties and were single channel jobs, some pointed toward the local stations, some pointed at Dallas. Some had rotors, some had multiple antennas on a mast pointed in different directions.

One other thing I noticed was when new antennas went up. In one particular case, I noted that two large, 5-element low band yagis had been taken down and a new all channel antenna touted as being a “ Waco Special” designed for the channels available in our area had gone up. I also noticed that the antennas that had been taken down were stacked against a fence in a back yard. They looked in good condition and had not been put out for the trash. I rode my bicycle down to the house and asked if they would like to sell them. As it turned out, sort of like I had hoped, when they learned I was doing experiments with television reception, they took it as unusual something a kid would do and told me just to take them. It two trips on the bicycle in a two mile round trip to get them home. It was a rather awkward ride holding the antenna out to the side with one arm and steering with the other. There were no accidents and they were soon stacked against the back fence in our yard.

I had wanted these antennas particularly because they appeared to be cut for the lower channels, probably Channel 4 if I had my guess. The small 3 element antenna I had been using had obviously been cut for Channel 6 and was noticeably smaller. The front to back ratio was pretty good for Channel 6, but on the lower channels, 2 and 3, it appeared to almost have more gain off the back than off the front. The length of the reflector element was probably more close to the length of a director on those channels and it easily could have been so. The “ new” yagis” I had brought home were noticeably larger with longer booms, wider spacing between elements and longer elements. They were also twin driven, probably for wider bandwidth. Many antennas of the day were like that. There were two folded dipole driven elements, one slightly longer than the other. They were connected together with metal bars that led to the connection point.

There was one thing missing. The two antennas had been stacked for additional gain. But the stacking bars that connected the two antennas ( sometimes called “Q-bars” by one manufacturer ) were missing. They apparently had not been saved when the antennas were taken down. I was not certain how long they were supposed to be, if the spacing between them was critical and how the impedances might match to the line.

It was back to the books to figure it out. I went to the Radio Amateurs Handbook and the ARRL Antenna book to try to figure it out. They had already been a help in making up harnesses to connect the separate high and low band antennas I had to a single feedline. We only had one run of 300 ohm twinlead running under the house and up through the floor behind the television.

Reading about stacking of antennas, I soon learned there were three concerns. Close spacing increased mutual coupling and lowered the feed impedance. The signals from the two antennas needed to be in phase to be properly additive and provide the extra signal. And increased spacing meant greater gain.

Looking at my current situation, I figured I could not put them more than fifteen feet apart. The stacking harness would have to be made of twin lead and would actually be longer than the spacing between them. After getting deeper and deeper into discussions about matching, I decided to just put them as far apart as I could mechanically manage, then use equal length feed lines to connect them together, letting that be the way they would be in phase and let the impedance chips fall where they may.

The two new yagis were mounted on the 20-foot pushup pole with me standing on the roof. The top section was telescoped down with the antenna mounted and twin lead harness connected to the top one, the mast pushed up and an insulated wooded standoff mounted seven feet down to take the strain off the mid point feedline connection. The rest of the mast section was pushed up to allow the mounting of the bottom yagi. The bottom yagi might not have cleared the roof had not my extra extension been put underneath the mast. Still it was close. That left two things for concern about performance...the close proximity of the bottom yagi to the roof and concern about impedance matching with the simply convenient, though equal, lengths of the lines connecting the two antennas.

The test was quick in coming. With the feedline connected, KRLD, Channel 4 from Dallas was selected on the TV and the antenna turned in the direction we already knew favored that station. In place of the somewhat grainy, slightly snowy picture we were used to seeing in the middle of the day with the old 3-element antenna, I saw a near perfect, local quality picture from the station just short of 90 miles away. Turning the antenna 180 degrees resulted in a tremendous drop in signal. The station was visible, but was deep in the snow. Turning the antenna 90 degrees off axis resulted in no signal at all from Dallas. There was a slight picture, which,with careful peaking turning up the San Antonio Channel 4 above the threshold of identifiability but still deep in snow. That was the first time that station had been seen without morning enhancement. Channel 5 from San Antonio was likewise just detectable. This was a great improvement! It was unfortunate that there appeared to be no sign of a Sporadic E opening that day.

It was three days before any sign of Sporadic E activity showed up. During the early morning hours there were good signals from temperature inversion enhancement from San Antonio, Corpus Christi, Houston and Port Arthur on the low channels.

That Friday, just before noon the tell tale signs of E skip appeared. Synch bars began rolling through the picture of the Dallas Channel 4. Running back and forth and rotating the antenna toward the east turned up a pair of stations battling for supremacy on the channel. The first turned out to be WFBC from Greenville, South Carolina. The other station was maddening to identify as over the next hour or so, every time a local commercial break or ID possibility turned up, the Greenville station would turn out on top. Rotating the antenna back and forth did not seem to make much difference. Finally in one commercial break there were some Florida references and the station was tentatively identified as WTVJ channel 4 in Jacksonville, Florida.

Two hours had been spent on this one channel identifying two stations and one was still just tentative. It was time to check the other low channels and see if something would be forthcoming. A check of Channel 2 showed only a slight indication of a signal. Hand rotating the mast to the southeast turned up not the usual KPRC channel 2 from Houston, but a Spanish language station that was very strong, with only a few flutters and occasional shallow fades. The ID when it came was unmistakeable: XEW from Mexico City. Rotating the antenna around to the west had that signal drop out, with no signal from San Antonio coming through south and southwest, but a further strong signal from the west that was soon identified as KORK from Las Vegas.

This was the beginning of a life long interest in TV and VHF DX. In the coming years, further antennas were tried. At one point, the antennas were supplemented by a 17 element log periodic antenna at 40 feet. This provided much better day to day reception of the stations from the Dallas area. It was easily noted that while the antenna had higher gain and smoother response over the entire VHF television bands, the front to back ratio of the LP was not as great as the single channel yagis. The increased height was of great help in reception of non-enhanced signals. However, comparison between it and the antennas at the lower height during temperature inversions and Sporadic E showed little difference in performance on weak signals. With regard to Sporadic E, experiments also showed that a single antenna sometimes performed better than the stacked five element antennas, perhaps confirming the idea that Sporadic E signals arrive at a fairly high angle. Stacked antennas would have a narrower response in the vertical plane. More distant stations might come in better on the two bay antenna, but ones not so distant might actually be weaker on the two bay antenna as the higher angle signals would be discriminated against.

I have often wondered if the same thing might not happen with temperature inversion signals. One thing that has been noticed over the years is that inversion enhancement or morning bending can actually reduce the signal strength of nearby signals by bending them away from their normal path. It was not only on tv signals. I noticed it on 2 meter amateur signals in the late seventies. At that time, while living and working in Port Arthur, I often had occasion to drive back and forth to Houston both in the evenings and in the mornings. During morning enhancement running only 15 watts on two meter FM, it was often possible to work Port Arthur base stations running similar power from the west side of Houston. A group of us operated simplex on 146.58 mHz.

There were two or three amateurs in Port Arthur who would talk with me as I drove in from Houston and at least one in Houston that would talk as I drove away from him. During non enhanced times, stations from Port Arthur were not even audible on the west side of Houston. In the times about an hour after sunrise, they would be quite strong and easily audible even through traffic, under overpasses and through areas of tall buildings in Houston. However, as I got closer to Port Arthur, usually from the vicinity of Baytown to near Winnie, I would lose the signals for a stretch of twenty five miles or so. This area was usually easy to communicate from during times of non-enhancement. It was also interesting that a little further down the road, the station from Houston would become inaudible, only to become readable, then very strong as I approached Port Arthur. In the case of that station, it would become inaudible in an area that was usually good for him during non-enhanced times and would come back in about the area where normally he would be lost without the enhancement. No scientific proof or reason for this, just  empirical data. I saw this happen on dozens of occasions. I have also noticed it in the reception of FM broadcast stations while driving on the road, having a station in well, then having it fade as I would get within 60 or 70 miles of the transmitter, only to have it come back in again closer in during enhancement, but having it audible at the same location again during non-enhanced times.

There is much I learned about VHF signal propagation in the coming years, including other methods of enhancement like dry line crossings, coastal bending, ducting along coast lines and meteor bursts. There were also further experiences involving UHF TV signals going well beyond normal distances.

In those early days and in days to come, there was a lot to be learned purely be experimenting. Part of the “art” of TV DX-ing is in minimizing the signals from the “normal stations” I could see, trying to give the weak, more distant stations a chance to be logged. Back in the sixties, all television was transmitted with horizontally polarized signals only. One was to minimize local signals other than turning an antenna away from them was to mount a yagi vertically. The cross polarization loss would take the signal down significantly. That along with turning the antennas to face 90 degrees away from them would really give the incoming skip signals a chance. Those arriving by Sporadic E wold be all tumbled and of random polarization anyway, and chances were being vertically polarized would with the receive antenna would not reduce the chances of logging a good one. These days, that won't work as most stations are now circularly polarized.

There have been times during Sporadic E openings that I have experimented with wire beam antennas to try to get more gain. On one occasion, I strung a rope up about twenty feet high running from northwest to southeast trying to get Mexican or Central American stations. I used wire elements that were actually in an inverted V shape with insulators on the ends and nylon string holding them out. The day I logged a Costa Rican station I had 12 elements strung from it.

There were other times that I did not have access to real TV antennas at all and still managed to log TV DX signals. In 1974 while in the Army after coming back from overseas, I spent about a year at Fort Polk, Louisiana. I was assigned to Headquarters Company and lived in an upgraded World War II barracks building. There were individual rooms and I was able to have my SWL receiver ( at that time I was using a Zenith TransOceanic and a National NC-190) and the Company Commander had allowed me to put up a pretty good antenna for listening. I had a 125 foot longwire strung between two buildings that was about 25 feet high. We were on the crown of a pretty good hill.

There was rudimentary cable tv service to the barracks buildings. It was actually little more than a community antenna system. In fact those were in the days before widespread cable tv programming. Signals were pretty poor on it and it wasn't long before I got the idea of tying the longwire antenna to the television just to see if even the semi-local signals would be a little better. I had already tried the longwire antenna for FM reception and had been really pleased at the results.

After trying various means of hooking up the wire, I ended up using two antenna impedance matching baluns hooked back to back. I hooked the longwire to one side of the 300 ohm side of one balun and grounded the other, then ran the 75 ohm side to the 75 ohm side of another balun, and hooked the 300 ohm side to the tv. There was no real scientific reason I arrived at this, it was just a matter of trying different things after connecting the wire directly to the tv caused some instabilities in the tuner.

The results were actually pretty fair. On a regular viewing basis, the stations from Shreveport, Alexandria and Lake Charles, Louisiana were all easily watchable with this arrangement. With some fading during the evenings, the Channel 10 from Lafayette would come in fairly well, along with Channels 2, 8,11, and 13 from Houston. This was much better than the on post community antenna which just provided Shreveport and Alexandria.

During on Saturday Sporadic E opening, many of my old friends from earlier days showed up, including stations from Florida and North Carolina. Of course there was no rotating the antenna. It was just a matter of waiting for one station to fade out and another to fade in. But it was DX-ing in a place you would not expect. ( And on weekends at Fort Polk, Louisiana in the seventies you took your entertainment where you could get it!)

I notice looking back at my log for May 30, 1974, Channels 2,4, and 6 from Denver came in rather late in the day, about 7 PM. Then a little later Channel 6 from Sacramento, California was easily identifiable. It was visible and easily watchable for well over an hour, not fading out until well after dark. Sporadic E this late was something I had not experienced up until this time.

Most mornings and evenings, UHF signals were enhanced enough to regularly allow watching Channels 26 and 39 from Houston, Channel 15 from Lafayette, Louisiana and Channel 33 from baton Rouge, Louisiana, all on the wire antenna!

My last experiences with TVDX on more than a casual basis came after I got out of the Army and took my next radio broadcasting job in Port Arthur, Texas. I lived in a two story garage apartment that turned out to be just perfect for a bachelor radio addict. There was a garage, living room and small kitchen downstairs and two bedrooms and the bath up stairs. The second bedroom was small and immediately became the ham/SWL/DX shack.

The first antennas for TV I put up were for UHF only. In fact, it was not so much for DX-ing that they went up, but for entertainment. Cable TV was not then what it is now with all of the abundance of non broadcast channels. While the local VHF stations carried all three major networks and had strong enough signals to be seen with indoor antennas, the closest independent stations with old movies and such were in Houston, with transmitter sites about a hundred miles away.

Over the next few years in the Port Arthur location, TV DX began taking a back seat to other pursuits, including amateur radio operations, including VHF Dxing, which is a whole 'nother story. There were numerous observations of TV DX on the UHF channels with a 40 element yagi up fifty feet. The major experimentation done here was with feed line. A local electronics store had a stock of old ladder line-300 ohm TV line with plastic ( I believe styrene) insulators at about eight inch intervals. Replacing the regular flat line with this ladder line made a tremendous difference in signal strength on the Houston stations available at the time on Channels 26 and 39 ( all that were on the air there at the time).

With the UHF antennas being the only ones up observations on that band were all that were there to be made over the next five years. There were several occasions where there were openings that allowed good viewing of the Austin and occasionally Dallas stations. The Channel 15 from Lafayette and the 33 from Baton Rouge, Louisiana were also often visible. I regret that job responsibilities, amateur radio and teaching radio classes pushed TV DX-ing aside during this period because I believe the proximity to the coast would have provided some great opportunities for logging even UHF stations at great distances. On other VHF and UHF bands openings across the water of the Gulf of Mexico down the coast of Texas and over to Florida were noted many times on the amateur, maritime and public service bands. Observations included enhanced long distance reception or transmission over long water paths and along the boundary layers between off shore and on shore air. But more on those in other chapters!

Suffice it to say, exposure to TV DX led to learning that very long distances can be covered on occasion by frequencies that would never be imagined possible, either by Sporadic E propagation or by tropospheric bending of one kind or another. In future times, signals on the VHF bands, either amateur or other, have been noted well over a thousand miles. Signals in the UHF range have been noted almost as far, though on less frequent occasions. And there have even been great distances noted on a few occasions as high as the 800 mHz public service band and one notable occasion in the 900 mHz Studio to Transmitter point to point band. DX adventure is indeed available almost anywhere you look for it!

Tuesday, February 4, 2014

Cold Winter's Nights in Front of the Radio

There has always been something rather special about listening to the radio on a cold winter's night. When I was young, older hams and radio enthusiasts talked about DX found on such nights. Even the old radio articles and books in “The Radio Boys” series talked about great loggings when things were cold, the air was crisp and the night was still.

I don't know if there is anything really to it or if it is just a matter of self fulfilling prophecy, but there does seem to be some magic there. Maybe its the often total lack of thunderstorm activity and its attendant lower atmospheric noise levels. Maybe its the lower Maximum Useable Frequencies that appear in the winter or less noise from the sun. Whatever it is, it at least seems like there is more to be found on those cold, still nights when the stars even seem brighter and sharper in appearance in the sky.

Perhaps that is why the big contests for the hams are in the winter, including the 160 meter tests. Maybe more stations end up in the log because its too cold to be out wandering the streets at night and thus more time to be spent before the glowing dials of the radios!

Whatever it is, you can count on more exotic sounds coming through the headsets on such a night. The low band signals seem to float airily in, sounding more like their higher frequency cousins when the 19,16,15, 12 and 10 meter bands are open to distant points of the globe.

For me, there are several examples. Like the night of December 21, 2103 ( morning of December 22 GMT) YU3AAA came in at almost S-9 on 3524.6 at 0347 GMT. Not a difficult signal pulled from amongst the grass, but a strong, dominant sounding signal that stood firmly out amongst its bandmates.

Just a few minutes later, at 0349 GMT, 9A5W from Croatia floated up from the background to really stand out on 1821.8 on the 160 meter band. It was followed by XE2S well over S-9 on 1825 only five minutes later, working a rarity, a deep South American signal from LU8DPS on the frequency.

Often whims will strike when things are logged, and for some reason I will be given the idea to check something else. Tuning a little lower to the standard AM broadcast band, a new one for me, XEARZ from Mexico City appeared on 1650 kHz with an S-6 signal holding up through the splash from a local 1660 station. And XERF on 1570 from Acuna, Mexico, always strong here, was coming in at an astounding 40 db over S-9. Who knows what adventures might have been in store if family matters had not called!

It was enough to get me to fire up the R-75 again the next night to see if more might show up. The 160 meter band did not reveal any treasures, but the SABC transmitter from Meyerton on 3320 was coming in at a good S-7 at 0332. And just a small turn of the knob brought the familiar “beeps” of Canada's time signal station, CHU, on 3330 at S-9 plus 20 db.( it should be noted that when on the lower frequencies, I only have one of the two preamps activated on the R-75)

There just aren't as many stations to be heard on the 90 meter band as once were to be found ( stations like TGNA and HCJB are long gone from the band) So the next broadcast station found was the always amazing ( at least here) Radio Verdad from Guatemala on 4055, S-9 plus 20 DB with only 700 watts ( if the WRTH is to be believed) at 0338 GMT. In addition to the strong signal, the modulation level on this station is always good and it appears to have particularly good audio processing. Normally during the summer months, this station will appear here with an S-7 to S-8 signal.

The evening surprises were still to come, as a 500 watter from Peru appeared at 0345 on 4775 with a really nice S-7 signal and then a carrier just detected on 4780 minutes later steadily rose in signal strength like a bird lifting from the water, to be identified as Radio Nationale from Djibouti!

To be fair, the reason this station can only be heard here in Texas with such good strength here in the winter is because its location with its local time at GMT plus 3 has its sign on time such that the night path is gone here in the summer time because the sun is just setting then as it is coming on. Thus another explainable reason for winter DX being special is that the paths are more amenable to prop to some locations given those station's schedules.

A few night's later, on what was actually the morning of December 28th GMT, I spent some time tuning the 160 and 80 meter amateur bands for DX during the Canadian contest.( I fish in the ham bands during the various contests because it is a target rich environment that particularly on the low bands, brings out targets not necessarily found on a “ normal night”) Starting about 0230 GMT on the 160 meter band it became apparent that there was not any really enhanced prop yet. While there were many strong Canadian signals, European signals just did not seem to be coming in. Signals from the Northeast US and Canada were very strong with VE3CX at 0249 and VE3EJ at 0254 well over S-9 on 1824 and 1825.6 respectively, both in Ontario Province. But no Europeans were to be heard. I have often noticed that just before Europe starts to prop in on 160 that the Northeast North American stations start to drop in signal strength or start to exhibit deeper fading.

A trip up to 80 meters showed a little more activity, with numerous very strong Candians, like VE1LD from Nova Scotia on 3520 at 0258 GMT at S-9. But even on 80 meters, Europe just wasn't happening. I found OM32WA from Slovak Republic on 3521.1 at 0259 GMT with only a 449 signal followed by SM3LIY from Sweden at 0301 GMT on the same frequency with only a 339 signal working a VE3 moments apart. Other signals on the band within single hop range were quite strong. At 0308 VE6AO from Alberta was S-9 plus 10 db on 3524.4 working VE4YU in Manitoba that was almost S-9. One good logging came at 0310 in the form of WL7E from Alaska on 3527.5. However, he was also not very strong here that evening.

Usually while trolling in contests I will start at the bottom of the band and move up, logging everything I hit. If the stations are calling CQ, I will listen for a couple calls to see if anything interesting responds, then will move up to the next station. With the double 250 Hz filters in the R-75 I can usually log a station every 200-300 Hz during crowded contest conditions. By logging everything coming in, I can later page through the log and get some idea of what was happening with the band in general. A good trick is to find a station near enough to this location calling CQ and holding with him awhile because stations answering him that will prop well to him will also prop well to me. If its a contest where DX stations try to work North Americans, this kind of brings the fish to the hook, as it were. Often this may mean that the semi local station may not be very strong here because he will be in some cases skipping over.

Tiredness coupled with the fact that not much appeared to be happening soon ended the night's listening at 0400 GMT ( 10 PM local time for me). The plan was to get up early the next morning and see if things were better.

But even that plan did not come to fruition. I managed to oversleep sunrise. I believe at that point that the flu that laid me low several days later may have already been nibbling at me because it seemed I was always getting tired. It was about 7:15 AM local time by the time I had the cats fed, the dogs walked and the coffee made.

By that time the sun was up and the lower frequencies had gone silent. I did find the Korean “Voice of the People” on 3480 still coming in strong enough to be identified at 1327 GMT.

I had come across a listing of aviation VOLMET frequencies during some internet searching earlier in the week and on a whim decided to jump up into the 6 mHz range and see if any of them would be audible. It has been years since I had actually sought them out, though I often tune past New York Air Radio between the 10 mHz WWV and the 30 meter ham band as a check to see if the band is open.( there is also a radio teletype signal that I have never identified that appears about 10.101 or so whenever the band is open.

After sweeping up through the 80/75 meter ham band and not finding carriers indicating broadcast stations, not even hearing Radio Nikkei or even Radio Verdad above the top of 75 meters, I knew it was time to jump to the higher frequencies.

Like I said, it had been a number of years since I had searched out the VOLMET frequencies and I do not have anything like a current frequency list book for utility stations, so I started with the sheets I had printed off the internet and unlike my usual method, did not sweep the band, but went looking for specific frequencies and found the following:

1332 GMT New York Radio Volmet 6604 kHz USB 5-7

1336 GMT Koltsovo Volmet 6639 kHz USB 3-3

1340 GMT JIA-Tokyo Volmet 6679 kHz USB 5-5

1341 GMT Novisibirsk Volmet 6693 kHz USB 4-4

1345 GMT VRK-20 Hong Kong 8828 kHz USB 4-4

1347 GMT Samara Volmet, Russia 8888 kHz USB 5-4

Checking the WWV's, I found the 2500 kHz S-9 +10 db with no trace of was already gone. On 5000 kHz, WWV was S-9+30 db, but WWVH was still well audible beneath it. WWV on 10 mHz was only S-9 with lots of fading and WWVH strong behind it.

By now it was 1359 GMT ( just before 7 am local) but VL8A from Alice Springs, Australia was still coming in audibly on 4835. There were Chinese coming in well on 4940 and 4980 and All India Radio was doing OK with audio easily heard on 4970. Checking 49 meters, there was still prop to the Far East with BBC World Service from Thailand well on 5875, VOA via Tinian at S-6 on 5890, Shiokaze radio doing very well on 5910 from Japan and the Voice of Vietnam in well but with lots of rapid fading on 5925 at 1415 GMT. Radio New Zealand was booming in with a good S-9 signal on 5950 just a few minutes later. Breakfast call ended that session ( Hey, there ARE priorities!!)

Shortly after this the flu bug hit, and with a vengeance. I was down over a week with the quacks saying it was the real Swine Flu. My wife ended up contracting it after I did so there was a good couple weeks before there was any significant time spent on the radio.

The next significant radio events in the household occurred on the night of January 16 Texas time, or Jan 17 GMT. Once again while out in the car, I noticed that distant broadcast stations at the high end of the dial were coming in well before sunset. By 5 PM local time, Cincinnati, Minneapolis and Waterloo, Iowa stations were coming in well.

It was also going to be a very cold winter's night and there was a 160 meter contest on, so I figured it would be a good night for digging for some low HF DX! The cold night did not disappoint.

Once again cold conditions existed over a good bit of the US with no thunderstorm activity. The bands were very quiet. It turned out to be a watershed night for logging stations.

After dinner and family activities were over, I settled in front of the HQ-170 and the R-75 in tandem began to tune the band. As early as 0210 GMT, 6Y5WJ from Jamaica was rolling in on 1825. Josh was working  VE7SL in BC, Canada with good signals both ways.

The band was flooded with stations. The narrow selectivity position on the Hammurland and the Icom were both pulled in tight and strong semi-local ( meaning Central US) stations were wall to wall, meaning one had to dig for the weak ones under those that were sending the S-meters well over S-9. The strategy began to look for mini pileups of stations and waiting to see who they might be working at the bottom of those stacks.

At 0221 I found one such stack on 1827.5. After logging a half dozen US stations ranging in strength up to S-9 plus 30 DB, I managed to hear the weak one they were calling. It took a few more before I could pull out the call sign, mainly because several stations in a row dropped their callsigns in seeking him without him identifying himself. It turned out to be a real treasure. TF4M in Iceland was coming in about S-4 when he was by himself. It took careful adjustment of the dual passband tuning on the Icom and careful shuffling of the Hammurland's BFO pitch to get him out from under adjacent stations, but there he was!

Iceland and Greenland both are a difficult catch from Texas, either because of the skip distance or the high latitude. There are also no broadcast stations that are likely to be heard here from there and the only chance to get those countries in the log are via the amateur bands or utility stations. Such is the case for many DX entities, so SWL's will often have to go to lengths beyond tuning the SWBC bands to get them!

A side note: Learning the use of passband tuning and other tricks with a receiver are art forms in themselves. Learning how to pull the most out of a receiver comes with patience and experience. The receiver will not do it by itself! The nicest receiver on the planet will not log someone as many stations or countries in the hands of a casual tuner as will an old or lesser receiver in the hands of a seasoned DX-er. It is worth taking time to “practice” around strong signals adjacent to weak ones, or tuning on bands that are in less than optimum condition to learn how to extract the most signal out of a noisy background or from adjacent to a strong one. On old receivers, offsetting the BFO pitch control to put the signals of interest in the best part of the passband is an old trick. Using notch controls or crystal phasing on old boat anchors will do amazing things sometimes. Playing with turning preamps on and off or using attenuators on the lower frequencies can also work wonders. Its like one musician told a man in New York who asked him how to get to Carnegie Hall: “ Practice man, practice!” And learn to listen intently and mentally discriminate. You will learn to ignore the noise or interference with practice. The best filter IS the one between the ears!!

But back to the story at hand. Its a cold night. The stars are bright and sharp in the dark sky. Such nights are indeed magic in more ways than one. Everything is still and when you walk outside the stars do seem like diamonds on velvet. Or if it is cloudy, its like a blanket is over the world and there is the damped feeling of true silence. Radio waves seem to like that. I don't know if its just imagination or hearing the old timers stories about DX on a cold night, but it has always seemed such to me ( Wups, am I falling into that category myself? Surely not!)

Just a few minutes after getting Iceland in the log and updating my countries list, Another pile appeared just up frequency. This one was actually easier because the station was identifying and actually sending a short CQ after each contact. Finland! OH1RX on 1829 at 0229 GMT. This one brought a bit of a celebration. Never had I heard a Scandinavian country on 160 meters or on any band of any type on that low a frequency! The cold winter's night was paying off. And it was just the beginning. There were several other European and Canadian stations added to the log that evening, though no new countries for 160 meters.

As sleepiness was overtaking, a quick trip up to 80 meters resulted in several Bulgarian stations being logged. While 160 meters was embroiled in its own single band contest, it appeared a Bulgarian contest was underway elsewhere. In less than five minutes, LZ9W, LZ8E, LZ2VU, LZ4A and near neighbor 9A1A from Croatia jumped into the log all within a couple kilohertz of 3525.

The next weekend was another cold one and another great time on 160 meters. Once again the broadcast stations had been in early. Once again it was very cold and the space heater was lit in the sunroom where the radios were set up. Once again the bands were dead quiet.

It was a fairly late start on the night of January 24 Texas time, the morning of January 25 GMT. It was after 9 PM local or 0300 GMT when I settled in front of the lighted dials of the HQ-170 and the R-75. Stateside signals were not as strong as the previous weekend, leading me to initially think it would not be that good of a night. However, it might have been that prop was just long because within minutes I heard Ecuador in the form of HD2A at 0318 on 1803. A good start! Ecuador was not a new country by any means, having been one of the first to be logged early in my shortwave listening career with HCJB all over the place and numerous stations in the tropical bands and probably hundreds of stations on the various amateur bands. But still a good catch on 160.

There were other signs of a good night ahead. The VE7's from British Columbia were much stronger than the Midwest stations. The same with the VE1's, the Nova Scotia station heard, and Prince Edward Island. One station in Georgia that I have heard and worked many times on the amateur bands while transmitting was actually well below his usual signal strength. He could usually be counted on to be well over S-9 and was only about S-6 and fading up and down. What was this??

The answer was soon in coming when I found a small pileup on 1810 and at the bottom of it was LZ0M from Bulgaria at 0324. Not very strong, but not difficult to pull out, either. Just up the dial about 750 Hz pounding in was Caribbean band regular KV4FZ from the Virgin Islands.

About ten minutes later, another new country for 160 meter DX listening popped into the log in the form of OM2VL from the Slovak Republic on 1816 at 0335. It was the beginning of a great run. Listed below are the highlights>

0345 S52AW 1827.3 Slovenia 559
0348 CS2C 1830.6 Portugal 559
0352 EA5BM 1831.5 Spain 569
0353 PJ2T 1832.4 Curacao 579
0354 3V8BB 1836 Tunisia 559 ( This was a surprise...great log entry!!!)
0356 9A3M 1823.2 Croatia 549
0358 ZF2KE 1837.2 Cayman Is. 589
0358/30 XE2S 1837.2 Mexico 599 ( working the ZF2)
0359 S59A 1833.4 Slovenia 549
0400 6Y3M 1834 Jamaica 589
0401 G6MC 1834 England 559 ( working the 6Y3)
0404 OM7M 1836.3 Slovak Rep 559
0407 I4WH 1839 Italy 559/579 QSB
0411 I4CEA 1840.35 Italy 569
0414 OK2W 1842.1 Czech rep 549
0415 IQ5TT 1843.4 Italy 579
0416 NP2X 1844.5 Virgin Is 589

About that time, fatigue began setting in, excitement or no. My usual day begins with me rising at 4 AM to get ready for work and by now the eyelids are getting heavy. And there is also the old feeling about knowing how to keep the hobby alive by “ leaving some for next time”.

The next morning, I returned to the radio about 6 am local or 1200 GMT for another slide through the band. I logged a few JA's beginning at 1222 all working the same US station that was calling CQ and attracting the Japanese crowd. In quick succession JA7FNO,JL3JRY and JH1OAI were in the log.

The band shortened up quickly after that and the stateside stations began to really gain in strength, with the West Coast being stronger and the East Coast first coming up, then beginning to fall in strength. It sometimes happens that way.

That night family matters took the forefront but the next morning, the 26th GMT, I was up at 5 AM local time (1100 GMT) and after feeding the animals ( cats are NOT to be denied when they want breakfast) and walking the dogs ( it was very cold and they did not tarry!!) I had the coffee on and the receivers warming up. The space heater in the sun room was on full and even at that it was cold and I had bundled up pretty well.

At first I thought it would be a fruitless morning. Stateside was strong with only a few Canadians showing up. Then I began to “feel” the band begin to shift. Its funny how one can sense things changing. The West Coast stations...the W7's..began getting stronger, then the VE7's and sure enough at 1136 GMT I found a pile of stations working RW0CF in Asiatic Russia. It took awhile to dig him out strong enough to claim him as logged. A check of the data base showed him to be in Khabarovsk, inland a ways and West of Japan. Perhaps the JA's would show up. He was very weak and it took listening through his ID's about a dozen times to pick it out.

I began to think it was an anomaly because I found nothing more but West Coast stations for the next several minutes, until JA1YDX turned up on 1816 at 1146, but also very, very weak.. Then it was again slim pickings for almost 20 minutes with strong stateside stations and the only DX showing up ZF2KE on Cayman and XE1TD in Mexico. ( and from Texas, that is hardly DX!)

Shortly after the top of the 1200 hour GMT, another pileup appeared on 1823.2. Again the station at the bottom of the pile was very weak and it took about ten minutes of intense listening to pull out an ID for NH0Z on Saipan. It looked like there would be a few things but it would be tough. I was afraid the morning was going to turn out like the day before with the band just dying early, or perhaps never really opening as the sun set in Asia.

But the lesson learned that morning was not to give up too soon! Once again the US 7's began to get stronger and then fade up and down a bit. At 1220 KL7KY from Alaska appeared on 1834.3 with a bit of a fluttery sound, like auroral effects, but peaked about an S-7 when he was up. I decided to stay around even though the thought of breakfast was calling. At the worst I would pick up a few states I needed if the band didn't stretch out. It was a good thing I did.

About ten minutes later, JH7PFD appeared on 1817.2 working a W4. Then at 1227 JA8PPC showed up calling CQ on 1819.4 and began to get a few takers. He Started out down in the grass and I was just lucky to find him in a fairly clear spot. As I listened, he climbed from barely audible to a respectable S-6.

Thus began a good run and some real excitement over the next half hour.

1234 GMT JA3YBK 1816 559
1242 GMT JH1MDJ 1813.7 449
1243 GMT JH7IMX 1813.7 449
1244 GMT JA2LCP 1813.7 549 ( These 3 all worked the same US stn)

But then came the high point of the morning up to that point. There was a pretty good pile on 1822. Several US stations were trying to work someone and he was just not copying them. Apparently they were as weak over there as he was here. Finally things thinned out a bit and I was able to pull out his callsign. A new one!! HL5IVL in South Korea! That one was celebrated with a “whoop” and a run to refill the coffee cup.

By now it was almost 7 AM local time and the sky was lightening up a bit as the sun was starting to rise. The East Coast stations were dropping way down, but the JA's were still in, albeit not very strong. I came across KL7KY again and he had climbed to almost S-9. With that being taken as a good sign, I decided to hang in and continue to tune. At straight up 7 AM local, 1300 GMT, JA1HGY appeared on 1813.36. He worked the KL7 along with several other stateside stations and other JA's. The ones I could copy were JA6JEW at 1304, JH1MDJ at 1307, JA9FHB at 1308, and JN7FNS at 1311. Sometimes this is a good strategy to find a station that the DX wants and just stay with him and let the targets come to you!

By now the sun is up. I am still hearing the West Coast, but one last JA at 1317 is so weak I can barely hear him...JE1ZWT on 1819. OK, just a couple more. I ran across a local station in town who almost bounced my headphones off my head calling CQ on 1820...K5LH, an excellent CW operator. I almost shut down at that point, but thought I would continue up through the DX window and maybe get one more before putting the bacon in the pan.

I got up to 1824.8 and the band was empty. But there was one station calling CQ with a call ending in “ DX” and stateside stations starting to get on him with “??” and “QRZ?”'s. Most gave up. It was too bad. But then  he managed to climb up for about 30 seconds and the ID was plain: BA5DX. Whoa! China logged on 160 meters. And it was light outside! The West Coast guys soon found him and he had plenty of company.

What a morning. Three new countries and some real DX in the SWL log. The cold winters night ( and morning. Brrrr!!!) had once again paid off. Maybe its not just legend....