Is It Worth Digging into MW today?

We all get used to the idea of band conditions changing while listening on HF.  The different bands are different by time of day or position of the sun,  conditions make long, slow changes with the sunspot cycle or with the effects of solar weather. Aurora can upset the applecart of the time-of-day changes.  Changes on HF frequencies are accepted as the norm and can come swiftly and suddenly.

Why is it, then, that it is difficult to imagine that happening on the medium frequencies?  Is it because we are used to listening to them with the expectation that our usual, local stations will always be there?  Because most of the time we are looking for something that is not DX, but something that is within groundwave range and dependable?

Sometimes, even those of us who have been digging out DX there for years have not noticed the day-to-day changes, chalking up hearing different stations on the same frequency to other factors, perhaps even using a loop or other form of directional antenna.

Truth be told, there can be tremendous differences from one day to the next, particularly during the grey hours of dusk and dawn. For me, this realization came about fifteen years ago  when I began doing quick band scans while commuting to work.  Because of the relatively short commute time ( not saying this to yank the chains of those with long drives each morning) of only about fifteen minutes in my previous job and less than ten minutes in my current one, I slipped into the habit of punching up a series of " regulars ". I had a list of a dozen and a half or so of stations that I would check in sequence while driving to work.  It, thus, became easy to notice any sudden changes from day to day.

There were also the seasonal changes among these same stations as sunrise time changes throughout the year.  These changes are gradual and through the year allow different signals to be heard on the same frequency as day light and darkness trade places from being east of me to west of me, or vice versa, as the seasons change.

But these seasonal changes are not what I am talking about.  They are the sometimes wild differences from one day to the next at the same sun-time. 

Sometimes they are measurable against a ground wave, or semi-local station. An example of this for me is WTAW in College Station, Texas on 1620 kHz.  Even though this station is 90 miles away, even on its night time power of 1 kw it is audible here in Waco on the radio in my 1999 Ford Ranger pickup. In the winter when I am driving to work maybe an hour before sunrise,  Cuba is audible in the background.  Some mornings it will be just audible in the background,  but some mornings it will be  blasting in almost enough to cover WTAW up completely. ( By the way for those wondering what  a radio station in Texas is doing with a "W" prefix callsign,  it was licensed in 1922 before the dividing line of the Mississippi split up "K's" to the west and "W's" to the east.  The station has changed frequency several times since then)

The same can be said for watching what happens with KSKY, 660 in Dallas, 90 miles in the other direction.  On their reduced nighttime power, they are marginally audible even at night, but some mornings or nights other stations cover them,  others they don't.  On this one, unlike WTAW where there is one dominant station that threatens to cover it, on 660, different stations may appear over them on different days,  showing heightened prop in slightly different directions from one day to the next at the same sun time.

On other frequencies,  skywave differences can be more dramatic.  In the mornings, on 890 some mornings WLS from Chicago will dominate,  while on others some station from Mexico will cover it.  At night, it might even be a Cuban,  depending on the band conditions.

In fact,  the Chicago station "skyline" can offer some real comparisons.  There are 50 kw stations that are capable of good signals into central Texas on 670, 720, 780, and 890.  If prop is good from the north,  they will all be audible. Other mornings, there may be stations either sharing the dial spot with them or completely covering them up.   It is interesting to note that at sunrise, the lower frequency ones will disappear first, often with WLS on 890 being the only one " left standing" as the sun comes up.

The sunrise effect also shows up on the stations from Mexico as well, with the lower dial position stations such as 540, 730, 900, 940, 990 disappearing in that order while 1000, 1030, 1050 and 1060 and particularly 1570 still booming in even after the sun is fully up.

Sometimes the band just before sunrise will show what amounts to "directional" characteristics,  with all of the Chicago stations coming in well and the western stations such as KHOW, KOA and KSL being below par.  Some mornings it will be the opposite, even from one day to the next at the same sun time.

It must be cautioned that in all this comparison, signals of different stations on different frequencies not be compared directly to other stations on other frequencies because there can be notable differences in facilities, power, or directivity of transmitters.  However, what can be noted is the relative difference between the signal strength of each station with what it appears to be on other days and noticing the different " amount of difference" between each when compared with itself.

For example, to show a difference in band conditions that is frequency dependent, one might note that the Chicago  780 station might be a tremendous difference ( say four of five s-units down in looking at a meter) while the 890 Chicago station might be only down three s-units from what it was the day before.

Or perhaps the 890 Chicago might be very low compared to the day before or even covered by  Mexico while KSL Salt Lake on 1160 might be much stronger than it had been the day before at the same time.

Sometimes aurora can cause some really unusual effects,  such as the more northern stations disappearing completely,  leaving new or previously unheard stations from other directions in the clear.

On a drive-to-work day noticing is about all that can be done as there is really no time to tune around and check other frequencies. If one is home or otherwise has the time to tune around it might be different.

In any event,  checking the "regulars" can be a clue whether its worth the effort to look around or spend the time doing something else,  perhaps tuning around on HF.

For me here in Central Texas,  there are several either/or frequencies to check. On 560, is it semi locaI in Beaumont or Denver?  On 630 is it San Antonio or Denver.  On 580 is it WIBW or XEMU?
Is there anything showing up behind KLIF Dallas on 570 or behind KTRH Houston on 740?  On 940 is it Midland or Mexico City? You get the idea. If things are out of the   ordinary, it might be time to fill up the coffee cup and dig in.

There is one other "beacon" I use here to determine how I spend my predawn time on the weekends. I tune up to 2850 khz and check on the strength of the 50 kw station in Pyongyang, North Korea.
Many might not even know such a station is even audible in the US.  However,it can be counted on to at least be detectable almost every morning. Some mornings it will be very strong. If it is strong enough clearly hear speech and music, it is worth spending time to check for trans-Pacific stations on MWcoming through.

I am not sure how all DX-ers are fixed for time but I am sure most find other things that compete for their time. For me, it is a full time job, family, household chores, contract work and writing (do I write for this blog or play with the radios!!) For others, there are surely other things that vie for your attention. Sometimes a little scouting about may help you decide how the time available might be spent. Do you look for MW DX, tune up through the shortwave bands or if its really bad, give up and turn on the telly (nooooooooo!!!!)

Even on the bad days there are things the died-in-the-wool DX-er can do, but we can look at that another day.  Until then,  good listening!!! 

W6LVP Loop Trial

After reading many reports about some of the "new" broadband, amplified loops and having had considerable experience with large unshielded tuned loops, and also having a vacation coming up to a coastal area, I thought it might be a good time to spring for one of them and give it a try,  especially given the increasing and intermittent high noise floor in my neighborhood.

For ease and quick shipping and a somewhat lower price,  I chose to go with the W6LVP loop after seeing several good reports among the Facebook DX groups that I have been frequenting.

I will say that the customer service, method of secure  payment and swift  delivery was very good and the antenna arrived in short order, well packed and of apparent good construction. Assembly, such little of it that there was, was very simple and intuitive.  The antenna is very light and is attractive.

I fired it up inside the shack only a couple feet off the floor and fed it into the R-75 only a few feet away.  the power supply was very quiet and there appeared to be no noise coupling from it even with the close proximity that I found it to be to the loop in the initial test.

Noise inside my house is a bit high due to multiple cell phone chargers, wifi, televisions, cable boxes and computer power supplies,  but with judicious rotating of the loop, noise was lower than the vertical out in the yard and considerably lower than the sloper.  Comparing signal strength of WWV and CHU showed about three S-units down from the outside forty foot vertical over 60 buried radials, but due to the reduced noise, they were all at least as readable on the loop inside.

Noise on the MW broadcast band and Low  Frequency band was comparable to the vertical. To be totally fair, rotating the loop inside the house showed noise coming from various locations,  with two of the main sources just about 90 degrees apart, so nulling both would be just about impossible no matter how good the loop would be.

The next day,  I mounted the loop on a temporary mast in the back yard about 20 feet from the house.  It was up about fifteen feet  above ground in the same general area of the yard as my vertical ( about ten feet away) and about 20 feet east of where the sloper traverses the yard.

Firing it up at that location gave it a much better chance of showing off its performance. In fact, it was a whole different world from when it was inside.   Nulling the major noise source was much easier, though there seemed to still be a secondary noise source whose null would require a position mutually exclusive to the position for nulling the worst noise source.

The first test run was done in the MW broadcast band at 0000 GMT July 23. This is over an hour before dark at my location in Woodway, on the west side of Waco, Texas.  To get an idea of just where I am, if you look at a map of Texas, look on the west side of Waco along Highway 84, a couple miles west of its intersection with Loop 340/State Highway 6. The following signals were logged as ground wave signals on the loop feeding the R-75:
XEMU     580 kHz   5 kw  Piedras Negras, Mexico  S-5 and steady
KLIF        570 kHz   5 kw Dallas, Tx S-9+10 db
KLBJ        590 kHz   5 kw Austin, Tx  S-9 + 20 db
KTBB       600 KHz  5kw  Tyler, Tx  S-5
KILT         610 kHz   5 kw  Houston, Tx S-7
KESB       620 kHz    5kw  Dallas, Tx S-8
KSLR       630 kHz    5 kw San Antonio, Tx S-7
Unk          640 kHz     1 kw  Norman, Oklahoma S-5
KSKY       660 kHz   20 kw  Dallas, Tx S-9+20 db
KKYX      680 kHz   50 kw  San Antonio, Tx S-8/S-9
KSAH       720 kHz   10 kw  San Antonio, Tx S-8
WBAP       820 kHz   50 kw  Fort Worth, Tx S-9 + 40 DB
KONO      860 kHz     5 kw  San Antonio, Tx  S-7
Unk           930 kHz     5 kw San Antonio, Tx S-7
WOAI      1200 kHz   50 kw  San Antonio, Tx S-9
KRZI        1660 kHz   10 KW Waco ( local) full scale

These were logged in a quick sweep mostly of stations I could identify by presence to get a quick idea of what was going on via groundwave before too much night effect prop would begin.

At 0100,  still a bit before sunset and still full sun at the WWV transmitter site,  a quick sweep of time and frequency stations yielded the following:
2500    WWV  S-5
3330    CHU    S-4 ( their transmitter site in darkness)
5000    WWV  S-9
7840    CHU    S-7
10000  WWV  S-9+20 DB
14670  CHU    S-7
15000  WWV  S-9+10DB
20000  WWV  S-7
25000   WWV Just audible carrier

The R-75 in all of these tests was being run with neither pre-amp on. Ambient noise on the loop was about S-1, while on the vertical was S-3.  It should be noted that the vertical had been put up in the quietest spot in the yard by walking a portable receiver around tuned to 500 kHz.

A quick tune around showed the Voice of Greece, a strong evening regular on 9420 at S-9+20 DB. A check of Radio Encyclopedia from Cuba on 530 kHz showed it at S-7, well above the noise and listenable.  On the vertical it usually runs S-9 but with some noise in the background.

A quick test of the low frequencies showed, as expected, it was well too early for the European and African Long Wave broadcasters to be heard. I quickly ID'ed a few non-directional aircraft beacons:
ARM  245 kHz  Wharton, Texas   S-5 ( about 200 miles)
PQF    248 kHz  Mesquite, Texas  S-7 ( about 100 miles...Mesquite is on the east side of Dallas)
ROB   400 kHz  Robinson, Texas  S-9+20 db ( local NDB 10 miles away)

A quick ham band test in the 40 meter cw portion showed:
0227 GMT   OK2RRR   7007 kHz  Czech Republic RST 579
0238 GMT   F5IN          7011 kHz   France               RST 579
0247 GMT   W0LI         7017 kHz   USA                  RST 589
0248 GMT   K9OM        7017 kHz  USA                  RST 599
0249 GMT   W7FW        7018 kHz  USA                  RST 599

Again, these were on the R-75 with no extra preamps on and with 250 hz filters in.

This being at the end of a long day and with other evening chores still ahead, this was the end of the first days testing.

The next day ( July 23, 2017) allowed time for a little more testing under daylight conditions.  Unfortunately my operating set up did not allow quick A-B testing between the loop and the vertical because I have no remote antenna switching and I was actually using the feedline that normally goes to the vertical to feed the loop.  The transmission line is about 100 feet of RG-8 X that is routed in an indirect route along fence lines to allow the shortest run across open lawn to the antennas. The RG-8X is not buried.

In a run beginning at 1436 GMT or about two-and-a-half hours after local sunrise, a run of the time and frequency stations yielded the following:
 25000 kHz   WWV   S-5
20000 kHz     WWV  S-7
15000  kHz   WWV   S-9
14670  kHz    CHU    S-4
10000 kHz     WWV  S-9 ( No WWVH)
7850  kHz     CHU     S-4
5000  kHz     WWV   S-8
3330 kHz      CHU     inaudible
2500 kHz      WWV   Just audible carrier

A run through the 20 meter amateur band resulted in  a logging of showed numerous USA stations at S-9 or better  At 1444 I heard VE2WU calling CQ on 14017 about S-5 followed by XE2AAW in Mexico at S-7.  No Europeans were heard in a quick sweep. WRMI on 9455 was S-9 at 1448 GMT. At about this time, rains were coming in and the loop was taken down from its temporary mast because the connections had not been waterproofed for this quick test.  The next few days saw several periods of thunderstorm activity, so testing was pretty much halted. The rest of the week was also taken up by preparations being made for the vacation trip that would include testing the antenna at the Gulf Coast.

This would be a real test as we were going to the coast in a passenger car rather than our usual Chevy Suburban and would have no room for large mast sections usually carried on the luggage rack on the roof of the Suburban.  The loop would be the only antenna taken.

We arrived at our coastal location about midday July 31. Radio activity would take place in the environment of family activity, so it would not be a full five days of all-out testing but it was hoped that a fair amount of " wringing out" of the antenna would take place.  It was mounted on a camera tripod with a short piece of PVC pipe extending above it to keep the loop away from the metal of the tripod.  The antenna was set up on a balcony about 15-18 feet above the ground and about a hundred yards from the water.

The location was at Crystal Beach, Texas on the Bolivar Peninsula about 12 miles east of Galveston, Texas.

The first listening came late in the afternoon of the first day and was a short one due to other activities including unpacking,  running errands to a local grocery to stock up on supplies and the first steps into the salt water ( priorities!!!)

A quick check at 2300 GMT showed our old favorite, the Voice of Greece on 9420 at S-9+20 db.
WWV on 10 MHz was S-9 with QSB and on 15 mHz was S-5 with QSB. A quick check of a few Medium Wave stations  showed WTAW on 1620 KHz, 10 kw,  from College Station, Texas ( about 160 miles) S-9 + 10db. KRZI on 1660 from Waco, also 10 kw was S-9, and while they were still on daytime power, there was some evidence of night effect as there was some QSB. KOGT 1600 from Orange, Texas with 1 kw about 75 miles away was S-9+10 db, but it should be noted that it is almost a water path from that location.  Thus ended the first evening of testing with swimming and dinner taking over!

With testing the next morning some disappointments began to show up. It was obvious that there was difficulty in nulling noise and many signals were just not what they should be. particularly signals to the north were poor. It was then discovered that the reason for this is that the beach house had been built with metal studs in the walls and the wiring for lights on the balcony were running within a foot of where the loop was set up. Tilting the loop to get it away from the walls of the house...so let it " see around the house" as it were and to get it away from the house wiring helped considerably. Signals via groundwave from medium wave stations to the north and east of us jumped 20-25 db or more and the noise was nullable. This would appear to be a consideration for anyone planning to use one of these loops made by any manufacturer.  Metal framing might be a bit of a problem, though other testing with the loop inside and near windows without metal screening outside showed fine results in the direction of the opening.  Turning the lights off on the balcony where the wiring ran so very close to the loop took care of  most of the noise problem. It would appear that the antenna will work very well inside if some care is taken with placement.  No antenna can perform miracles if not given a chance!!

After the antenna rearrangement, reception on the low frequencies was quite good.  The dial was full of low frequency non directional beacons,  with dozens heard very well beginning the next morning about 1600 GMT ( 9 a.m. local time) with many heard from all over Texas, Louisiana and a few from Mexico.  The noise floor after antenna rearranging and nulling was about S-2.  The carrier for the WWV station on 60 kHz was even heard.

Daytime reception on medium wave was quite good. A sampling of more " interesting" MW loggings that mid morning ( starting about 9:30 a.m. local):
KTSA  550  5 KW  San Antonio  S-7
KLVI   560   5 kw   Beaumont, Tx S-9 + 30 db
KLIF    570   5 kw   Dallas, Tx  S-5
KJMJ   580    5 kw  Alexandria, Louisiana  S-4
XEFD  590    5 kw  Reynosa, Mexico S-9
XEGH  620    1 kw  Reynosa, Mexico S-7
KSKY  660    20 kw  Dallas, Tx  S-6
KKYX  680   50 KW San Antonio, Tx  S-9 + 10 db
WQNO 690   10 kw  New Orleans, La S-5
KEEL   710    50 KW Shreveport, La  S-5 ( a loooong way for daytime groundwave!)
KSAH  720     10 kw  San Antonio, Tx  S-9
KTRH  740     50 kw  Houston, Tx  Full scale.

Rotating the loop seemed to indicate a pretty broad main lobe but a fairly deep and narrow null.

I ran through 31 meters about mid afternoon, at a time I thought would be before the night time enhancement of those frequencies with a later run through the same band near sunset. Here are a few samples with the sweep beginning at 2000 GMT, or 3 p.m. local time ( actually 2 p.m. local sun time given that we are on daylight savings time...something easy for me to forget!)  This was with the loop attached to a eight foot long piece of PVC pipe and extended out from the balcony to get it away from the metal in the walls and the wiring in the  ceiling.

V. of Greece           9420 S-5
Voice of Turkey    9460  S-7
R. Saudi                 9555  S-8
R. Marti                  9565 S-7 plus jamming...could null the jamming!
Voice of Turkey     9635 S-5
R. Guinea               9650  S-4
R. Saudi                  9675  S-7
R. Saudi                 9870  S-5
V. of Greece           9935   S-5
WRMI                    9955   S-9+10db

The noise floor was about S-2 with the loop extended about four feet away from the balcony.

Another run through 31 meters beginning at 0030 GMT or 7.p.m. local or a little over an hour before local sunset with the loop in the same position as above:

V. of Greece    9420   S-9+20 DB
WRMI             9395    S-9
WBCQ            9330    S-9+10 DB
Strong rtty sig 9317     S-9
WINB             9265     S-9+10 DB
Nauen, Ger.    9450      S-7
WRMI            9455      S-9
CRI Kashi      9470     S-6
Issoudon         9490    S-9+20 DB
R. Transmundial 9530   S-4  (Brazil)
R. Havana       9555     S-9
R. Boa Ven.    9550     S-5 Brazil
CRI/Rom.       9570      S-9+ 20DB
CRI/Cuba       9580      S-9+ 10 DB
CRI SP kasha  9590     S-4
R.Cancoa N.   9675      S-5 Brazil
RRI                 9730      S-9+ 10 DB
V. of Turkey   9830     S-9+ 10DB
VOIRI            9880      S-5  ( Iran)
V. of Greece   9935      S-9+10 DB
These are all on the R-75 with no extra preamp turned on.

Later at 0200 R. Sonder Grense on 3220 from Meyerton, S. Africa was in very solid at S-9 and listenable without objectionable noise.

I hope this is not getting too boring with too much listing, but I figure that this is the best way to show the performance of the antenna, particularly for those in the Central US and hopefully for those elsewhere looking at a map and sort of imagining tuning and listening get some idea what one could get out of this antenna.

Below is a quick run through of the "usual" Mexican  and Cuban MW stations heard nightly, previously on wire and vertical antennas beginning at 0250 GMT just getting into post dusk darkness:
XEX              730         Mexico City  S-9+20 DB
CMBC           890         Cuba              S-7
XEW             900         Mexico City   S-9+20 DB
XEQ              940         Mexico City   S-9+20 DB
XEOY          1000        Mexico City   S-9+10 DB
XEG             1050        Monterrey, Mex  S-9+20 db ( 150 kw)
XEEP            1060       Mexico City   S-9+ 20 DB
XERF           1570        Ciudad Acuna, Mx  S-9+30 db
R Encyc.         530       Cuba                S-9

All of these signals are more than comparable to how well they are received at home on both the vertical and the sloper, again with noise floor measured at 520 kHz of S-2.

The last " acid test" I gave the antenna was the look at the sunrise Pacific/Asian opening the next morning beginning at 1130 GMT or 6:30 a.m. local time, just as light is beginning to appear on the horizon. Noise floor measured at 2800 khz S-2
2850  KCBS North Korea  S-4  very readable
2500  WWV S-8  with WWVH audible in background
3320  Pyongyang BC S-4
3325  Bougainville and Indonesia mixed  S-5 "bouncing"
3480  Voice of the People S Korea S-5
3910  Voice of the People presumed S-5 and jamming
3925  R Nikkei S-5
3930  Voice of the People S-5
3945  R Nikkei S-5
3985  Echo of Hope  S-5 and jamming
4055  R Verdad S-7 QSB ( interesting notably with not as good a signal as at home!)
4212  WLO  CW/SITOR  s-9+10 DB
4735  R. Tarma Peru S-4.

There were some thunderstorms that developed in the area the next couple days and this led to disappointment in doing more low frequency work and I did not hear any of the European or African Long Wave Stations or MW stations.

Overall,  for its size, the antenna performed admirably well.  It was great to have an antenna to take on a trip that was not a huge chore to pack and set up. It might have been good to have some mast sections that could have allowed the antenna to be set up at a distance from the house and more in the clear.

I have noticed the same here at home.  While it works well indoors, at least much better than an indoor random wire, it does much better outside and in the clear.  Getting it up fifteen feet or so  really seems to help.  The next plan at home is to put it up on a telescoping mast up about thirty feet.

One observation is that other metal objects very near do seem to affect the ability of the loop to null noise. Dropping the wire sloper at home that had been running near it greatly reduced the noise that apparently was being coupled into it.  If one is using one of these type loops it would proibably be worth the effort to keep it at least a moderate distance away from other antennas,  particularly large wire antennas.  If those other antennas pick up noise where they run,  they could couple that right back into the loop or provide an additional place to be nulled, thus " nullifying" one of the advantages of the loop.

The loop does result in somewhat lower S-meter readings on some signals, but the lower noise floor more than makes up for that.

QSB does seem to be more pronounced than on the larger antennas but that is probably just a result of the smaller aperture and less of a "diversity" effect thereof.

During the test period, I noticed that the antenna did seem to perform better on the lower frequencies, but that might easily have been the result of band conditions,  so consider that a caveat.

I was hoping to hear some DX on 160 meters,  but during the week and during a non contest period there is not a huge amount of activity on that band, so that should not be misconstrued.

All in all,  this antenna has proved worth the expense and for those with limited space or even living in an apartment, I can highly recommend it as a way of getting some reasonable DX.  If you have a balcony, all the better...and if you can get it extended out beyond the balcony, even better yet.  As with any antenna,  giving it an even chance to work by putting it in the best possible location is a given.  If you are in a home with metal framing ( aluminum studs in the walls, etc) do your best to get it at least near a window without metal screening.

I am already planning a way to get the radio and antenna out totally away from wires and walls.  Running the R-75 and the loop both off a 12 volt battery is easily possible.

One note: Despite being in the " hot lobes" of directional antennas from three different 50 kw stations including one that  effectively "pinned" the S-meter on the R-75 ( OK, drove all the lights on...) there were no overload issues.  The Galveston station on 1540 khz runs 2500 watts but its directional had its main lobe right over our vacation location with only salt water between us and  it was not a problem.

There is always a risk in evaluating an antenna over a short period of time given how band conditions can vary.  That goes not only for this report or for any antenna you might try or put up. Poor bands can make the best antenna seem lousy on the first try and listening with extra care on a new one can sometimes give an impression in the other direction.  Always give one time,  and particularly with small antennas like loops,  try different locations and give them an even break to give you what you want.

Again, I hope the station listings were not too boring, but figured it was the best way to show what the thing did. As always, comments welcome.

WWCR                  9980  S-9

By What Path Do They Get Here

I was asked in one of  my Facebook groups how signals travel to their destination, or by what path do they come. The simple answer is " by a Great Circle path."

What does this mean?  Well if you think back to geometry class ( I know that is asking a lot!!) the definition of a great circle on a sphere is  " a line on the surface of the sphere defined by the intersection of a plane passing through the two points in question and through the center of the sphere"

OK, so that is a little esoteric. Think of it this way. Take the equator line and tilt it so that it passes through the two points, or cities, that you are looking at.

If you look down on the line while holding a globe,  this path looks like a straight line.  but if you look at it on a flat map it will look much different,  most likely as a curved line. If you are familiar with what is known as a polar projection, or a flat map made up as a circle with the center being the north or south pole you can get a better idea of what is going on. A really good way to look at it would be if you could find a polar projection based on your own location.  There are computer programs that can do this for you and I would be willing to bet with a little judicious searching on the internet you could find a website that can do it.  You would just need your latitude and longitude to enter.

Sometimes the direction from your place might be much different than you would intuitively think.
Like who would think that the beam heading for Alaska and Japan would almost be the same from Central Texas.  Of that the beam heading for Europe and East Africa would be almost the same.

You will notice if you do this mental exercise or even look at a globe with the two points actually on the equator that there are two paths between the points: the short one and the long one.  Thus the definition of " long path" and " short path".

Logically the shortest one is the one by which the signal you are hearing arrived,  and most of the time this is true. However, there are times and conditions under which the signal can arrive the other way round, or in some cases by both.

Which way it comes depends upon the time of day, frequency and general band conditions. If you are where I am, in Central Texas, the shortest distance to Australia is to the southwest over the Pacific Ocean.  If I want to hear or work an amateur station in Australia on forty meters, the best time for short path is early in the morning my time. That insures that the signal will have a darkness path most of the route.  Often the window is short depending on where in Australia the station is located, because the sun will be either just going down or has been down a little while  the sun is almost about to come up here. Propagation on forty meters ( 7 MHz) the other way around in the morning my time is simply not going to happen because that path is in full sunlight most of the way.

But let's take a look at " the other end of the day." Just before sunset in Texas, in some parts of Australia the sun is just rising, or just about to rise. The path the long way round is in darkness most of the way.  Prop on forty meters usually lasts a little beyond sunrise at most locations, sometimes by an hour or more.  If on that particular day, conditions are such that the Maximum Useable Frequency happens to be fairly low. it just might be that prop can begin a little before sunset and continue until a little after sunrise,  just enough to allow the signal to get through, and you get your signal via long path!

Now what direction is the signal going? Logic might try to tell you to the southeast from Texas, but that is not correct.  The signal still follows the Great Circle path,  which means it goes Northeast, up and over Europe, then down toward Australia.

Long path prop does not happen every day or on every frequency. There are a number of factors that might determine whether it will occur or not.

First, for the lower frequencies, there still must be darkness over much of the path. There might be some stretching at either end with some light if the first hop could still be in darkness. This can occur if the frequency involved is at the higher end of the range that can be propagated in darkness. For example, my most frequent success on the amateur bands for long path prop to Australia from Texas has been on the 30 meter band. There are times that rather long hauls can be made in the late daytime or near dusk that might make the first hop possible even a couple hours before sunset. The subsequent hops would then be in darkness.

For shortwave listeners,  the closest approximation might be the 31 meter broadcast band.  In the winter hemispheres, 25 meters might be too high for good prop after dark at the higher latitudes and would not make it,  but 31 meters might. We all know that 31 meters does well until a good ways after sunrise as evidenced by NHK from Japan and Radio New Zealand being listenable after sunrise in North America ( and of course, the now gone Radio Australia on 9580 was often listenable well after sunrise while it was still on the air)

There are times that the 40 meter amateur band and the 41 meter shortwave broadcast band can provide the same kind of performance.  The only difference is one must be much closer to darkness for it to work.

There may be exceptional times where prop can occur over both paths at the same time. I have noted this most often at higher levels of sunspot activity on the higher bands that can still sustain prop at night. This kind of prop is characterized by a pronounced echo on the signal brought about by the different transit times for the two paths. My earliest experience with this occurred listening to the VOA relay station in the Philippines back in the early sixties.

As a side note, echo does not always indicate both long and short path prop.  There are also times that I have noted Pacific or Japanese stations with pronounced echo in the mornings that is the result of something else altogether. It is a phenomenon known as " Backscatter". This occurs most often when a station in the Philippines or Japan is beaming a signal away from North America. Some of the signal arrives direct path off the back of the antenna. ( One must note with care when looking at beam headings listed for broadcasts.  Just because a certain beam heading is indicated does not mean that there is no signal sent in other directions.  Even if the front to back ratio of an antenna array is 20 db or even more, if the station transmitter is using high power in the 100-250 kw or more range and the effective radiated power in the main lobe is nearly a megawatt, 20 db down in the opposite direction is still a power level high enough to provide a fair signal. Twenty db down from an ERP of a megawatt is still 10 kw!)

In backscatter, signal that arrives at a distant point from a transmitter often has some bounced back toward the transmitter, and if the prop is good, can hop again toward a listener off the back of the antenna, too.  The difference in transit time can give the echo effect. Some times because the backscatter signal has originally come off the front of the antenna with much greater power and the "direct" signal was radiated with less power,  sometimes the echoed signal can be noticeably stronger than the direct signal,  giving a really strange effect of the echo being louder than the first part you hear.  Sometimes this effect is so pronounced that it can be difficult or impossible to understand the words being spoken.  On a cw amateur band signal,  the delayed dits and dahs can fill in the spaces and make the signal absolutely impossible to copy.

This is a bit of a digression, but because backscatter is an interesting phenomenon perhaps it should be included here. And in a way it fits because it can provide an anomaly in the direction from which a signal appears to come.  This happens most noticeably on the ham bands, but conceivably could happen with broadcast stations, too.

There are times when a relatively nearby station--that is, one too far away to be heard via groundwave but within the "skip zone" or area where the signal is usually not heard because it quite literally "skips over" the receiving site--can be heard, usually with a fairly weak and often very fluttery sound.  What is happening in this case is that the signal is being heard totally via backscatter. That is, the signal is going from the originating signal through the first hop distance, then when it hits the ground or water, while a good bit of the signal goes forward for the next hop,  some of the signal sort of "splatters" and usually most of it goes back in the general direction from which it came, making it audible in the general region where it originated.

A good example of this would be a Texas station being heard on 10,15, or 20 meters by other stations in Texas and Louisiana perhaps well beyond groundwave range but " too close" to be heard by skip. It has been my general observation, by no means meaning that this is the only time it happens,  that this occurs usually right before the band goes out to the original target area.

When this happens, some of the backscattered signal might go off in a range of azimuths, allowing the station to be heard in other areas besides where it was originally targeted or where the "regular skip" path would have taken it.  This would lead a receiver of the Texas signal in, say, Mexico or Central America, to say it appeared to have come from the west or southwest, making it appear that the signal came by the odd path if the receiving station were using a rotary beam of some kind.  It would peak up as coming from the point of the back scatter rather than from whence it really came.

This is where I believe the fabled phenomenon some times called " one-way skip" comes from.  If the station hearing the Texas station via backscatter were to try call or answer the station,  the contact would never be made because the chances of the answering station making the trip back to the original station via backscatter from a different angle would be very small indeed.

Other echo effects can occur on signals whose paths take them through the auroral zone in the arctic.
Signals get tumbled and jumbled and can take on a watery or echoey sound.  This often happens in the amateur bands in the Central US when listening to signals from Sweden, Norway, Finland and north-central Russia. As in the case of backscatter,  this can make a phone signal hard to understand or cw all but impossible to copy. On the amateur bands, when trying to work a station in Scandanavia or northern Russia on cw under these conditions,  the old school guys know the thing to do is to SLOW DOWN and put more spaces between characters so the echo doesn't kill your intelligibility.  This is why I always keep a straight key at the ready along with my Vibroplex bug and electronic keyer!

Gray line prop is another condition that can often make signals appear to come from a different direction than they " should"  There are lots of theories about what brings about so-called gray line enhancement, in which signals seem particularly strong along the boundary between daylight and darkness.  I make no claims to understand with any certainty what actually occurs,  but have learned to take the " bonus " signals or signal strength and enjoy it. There are times when the signals seem to come from other directions than they should.  Sometimes the best thing to do is just log 'em and don't worry about it.  If using a directional beam antenna,  just rotate for best signal strength and don't look at the azimuth indicator.  The bottom line: get them in the log!

One other time in which signals can appear to come from a different direction than they should is during Sporadic E propogation on VHF frequencies.  I have noted times when it almost appears a signal has taken a right or left 90-degree turn when arriving.

This happens when the signal arrives by multiple hops.  Sporadic E occurs when highly ionized patches or clouds form in the mid level of the ionosphere with the ionization levels high enough to provide reflection of signals well into the VHF region.  Sporadic E can also extend into lower frequencies, but usually only down to 25 MHz or so.

If there happens to be two different sets of E layer clouds and IF a signal bounces off one, strikes the round in such a way as to scatter and perchance strike a second E layer cloud somewhat off azimuth from the original path,  the signal path could in effect, be bent.

Sometimes during a really wild sporadic E opening one can almost wear out a good antenna rotator trying to figure out where best to point the antenna. Again, its often best to just leave it where the signal is best readable and not worry about it.  Truth be told,  often Sporadic E signals come down at such a steep angle that they strike the antenna from high above and it probably matters not which direction its pointed.

How do we predict these things?  Well,  that could be a really tricky business.  One could spend so much time trying to do it that there would be no time left for DX-ing.  And perhaps this is where differing philosophies come in.  Whether it be double hop Sporadic E,  grey line prop, long path prop or whatever,  there are some who would try to assign numbers, develop models,  look at the physics of the thing and basically geek themselves almost into a coma trying to predict and figure them out or explain what's happening.

It is my personal feeling that while this is well and good and a great academic exercise,  for me THIS IS A HOBBY!  While there are some fishermen who do the same thing,  others just go out and fish.  I go out and listen.  For me, what is more fun is to turn on the radio,  tune around and get a feel for what's happening and then intuitively shop for the best DX.

I have often said that DX-ing is a lot like fishing.  One learns to read the signs and then just know where to look and how to look. Experience has taught me that some indicators indicate certain conditions and to let that guide where I look.  There are some tools that can help a bit, like the prop forecasts.  Though if I had paid attention to prop forecasts that called for poor conditions or some kind of disturbance, I might never have turned on the radio and missed some great stuff.  But I have learned that when there is supposed to be no prop,  often folks do just that and there is little activity.  But if there is a little atmospheric noise and one tunes around, someone might just find somebody rare and distant hopefully calling CQ.  I well remember stumbling across my first Guam, Johnson Island, Banaba, Christmas Island and a few others just that way!!

Sometimes another "new school" barometer to look at is DX Summit or some of the other DX reporting sites that post real time signal spots.  Take a look and just see where the stuff is coming into various areas and on what frequencies.  This is even useful to the non ham or listener who is not interested in ham stuff.  But what is happening on the ham bands can be a really good barometer on what is happening on the nearby shortwave broadcast bands.  Forty meter spots being a good barometer for 41 meters and to a lesser degree for 49 meters. Twenty meter and seventeen meter spots are good indicators for 19 and 16 meter shortwave stations.  Thirty meter spots are good for 31 meter shortwave conditions and to a lesser degree 25 meter shortwave broadcast spots. Sixty meter spots are good for, well, the 60 meter shortwave band. And so on.....

But I am wandering a bit off track here.  Hopefully this will help some get a feeling about how things appear to me to work. This is based not on textbook theory, but over fifty years of observing what really happens out there.  Sometimes it seems better not to worry so much about the why's of something and to just jump in and take advantage of it.

Good DX-ing to all, and as always, I am happy to hear from anyone with their own observations and ideas through the comments section of this blog or through the Facebook groups you can find me on.
Don't forget,  if the bands sound dead or the signals sound weak,  don't turn the radio off-get in there and dig around.  You never know what might be lurking in the radio shadows.

                        

Dahlak Island Adventure-9F3USA/P1

      In 1972-73 while assigned to Kagnew Station in Asmara,  Ethiopia ( now Eritrea) I had some great opportunities for SWL and Ham DX.  As part of the radio club there, I had the opportunity to operate the club station ET3USA.  The club had a block of callsigns assigned to it that allowed a limited number of hams to operate under the license off post, using the callsigns ET3USB-ET3USF.  This was in the early 1970's. Some of that activity will be the subject of future columns.
       Early in the Spring of 1973 I was approached by Mike Durbin, WA5TKC, with an invitation to join him and KP4CKX who also worked at facilities in Asmara in what he termed a " mini-field day" operation he had planned. Turned out, it was what amounted to a short DX-pedition to an island in the Red Sea.
       The plan was to go in late May to one of the islands in the Dahlak Archipeligo off the Ethiopian Coast near the port of Massawa.  Mike worked the details out with the local government authorities, which was no mean feat given the political situation at the time.  There was rebel activity in Eritrea at the time and any use of radios out in the field might have been suspect.
       All the hurdles appeared to have been cleared and early on a Friday morning, a group of us caravanned down the 72-hundred foot mountain to Massawa to catch our ride to the island.  That drive was always an adventure in itself, being on a two lane paved road that would not exactly be considered a highway. It was a 110 kilometer drive containing 27 switchback turns.
       In addition to the three of us who would operate the radios, a group of a half dozen others were going along to go fishing.  That helped spread out the cost of chartering the boat and also would cut down on the provisions we would have to take. The operation was going to basically be a long weekend,  and would be nothing like the heavily financed trips taken by groups these days.  I think we figured the total cost of the trip, including gas to drive up and down the mountain was about $300 US!
       All of the equipment taken fit inside one small footlocker.  The radios were two Heathkit HW-101's, tube type rigs that ran about 100 watts out. There were two rolls of wire, some nylon rope, mikes and keys and paper for logging. ( No computers!!!). There was a 1 kw gasoline powered generator. Outside the footlocker, we carried three Jerry cans for fuels, a couple cans of oil and the antenna, which was a 14AVQ trap vertical that covered 40-10 meters. There were also a half dozen or so short poles that would make up a short mast.
       The plans were to operate one station at a time on 40-10 and to string an 80 meter wire for communication back to Asmara.  Our ride out to the island would be on a 40 foot Arab fishing dhow powered by sail and small inboard engine. It would be about a four hour trip from the harbor to our destination. This would not be a luxury trip. Seating was flat on the open deck.  Any cooking on board would be in a small sand pit on the forward deck!
       The first problem came after all the gear was loaded on the boat in the harbor.  Government officials came by and wanted to inspect everything again.  They wanted to do so out of our sight, so we went to a nearby restaurant and had an unscheduled early lunch break, followed by ice cream ( which for me turned out to not be a good thing later!!)
       About two hours later, we were finally able to leave the harbor. Water was smooth in the harbor, but not so much when we got out in the open water. Seas were a little rough, and for awhile it was great fun to stand in the bow of the boat and have the spray hit me in the face. About an hour later, the trouble came when I went back amidships to sit down on the deck. Then the effects of the spicy meal and ice cream hit along with the first signs of queasiness.  Someone told me not to look at the horizon, but to look only at the deck to stall off the seasickness. I tried that, but the movement of shadows from the rigging moving back and forth on the deck finally did me in!  I had no sea legs!
       It was a miserable couple more hours until we reached the smoother waters near the coast of the island. I was still a bit queasy as we made our approach, but all that ended when a minor disaster struck. The small boat ran aground!  The boat's operator did not seem too concerned, saying we should just unload there.
       We all went over the side and found the water to be about neck deep.  It was time to lower the equipment over the side and carefully carry it over our heads to shore. Somehow we got everything ashore with nothing getting wet, not even the logging paper!
       It was then that we got our first look at our operating situation.  There was a small shelter made of driftwood already in place that provided a little shade. There were higher dunes about 100 feet back from the water line.
       The first order of business was to get the generator started and checked out. It was set up a hundred feet from the shelter to keep the noise down a little. The whole expedition almost became just a fishing trip at that point as the generator simply refused to start.  Murphy's Law was in full force.  The generator that had started many times on the first pull back up on the mountain was being cantankerous at sea level.

       Mike and one of the fishermen did some kind of magic that also appeared to be some kicking, then playing with the carburetor that finally got it going.  I am guessing that perhaps some adjustment on the engine to make it operate in the thin air on the mountain top might have been the problem.
      The next step was to get the antenna put up.  That ended up being about a fifteen minute operation...just stacking the tubing for the vertical together, driving some stakes into the sand, standing it up and guying it off.  Unfortunately, I have no pictures of the antenna, but there are some pictures of the antenna and the boat in either the July or August 1973 QST magazine DX column.
The vertical was set up right at the water's edge with radials running off into the water.  We did not have enough coax by just a few feet to have the antenna out in the water itself at low tide.
       It was now time to set up the gear.  The operating tables were two portable tables that we set up under small shelter, running the coax out to the vertical and firing up.  An end fed wire was strung from the shelter up to the small mast that we put on top of the nearest sand dune. It would be for our 80 meter link back to Asmara about 120 miles away. We tuned up one of the HW-101's into the wire first.  There was no antenna tuner, one of the advantages of old school tube type radios.  The Heath radios had a pretty wide range pi-network output circuit and we did not even worry about the match. The plate current dipped and loaded and that was that! Communications was established with ET3USF and our safety line was secured.
       The other HW-101 was loaded up into the vertical.  It appeared to load up easily,  without too many dips and loading adjustments. We were set to go, almost on our planned schedule.  We had put out the word via the ARRL that we would be on the air by 1600 GMT.  The delay at the harbor and the increased time to unload along with the problem with the generator had pushed us right up to that time with nothing to spare.  Our local time was GMT plus three, so it was 1900 our time. 
        I really don't remember if we had announced a frequency on which to look for us or not,  but we found a clear spot below 14300 as I recall and put out a CQ, signing the callsign for the expedition,
9F3USA/P1  (" Nine Fox Three Uniform Sierra Alpha Stroke Papa One" a real mouthful!)  I don't know what we expected from that one short three-by-three call. Maybe we thought the world would fall in on us right away,  so it was a disappointment when there was silence. It was the same after three such calls.  Then Mike made a rather lengthy CQ call and unkeyed. After a short silence, a tentative call came back: I8HH.  I remember that call well being the first that we worked.  The exchange was a little longer than the usual expedition contact being the first and the fact that there was no crowd.  I remember he repeated our call a few times, perhaps thinking it would attract attention to us.  It did.
       When Mike cleared the contact, there were three stations calling.  He worked those quickly, and then the roof fell in. The pileup was on.  We worked a string of Europeans, then one JA who said he was going to announce our presence on a two meter repeater there in Tokyo.  Things got really heavy after that with several pages of JA's worked in quick succession!

       The pictures are a little faded with age, but here you see WA5TKC ( on the right) and myself (WA5IEX) on the left.  The covers were off the '101's ( and us!).  There was no concern about RFI or TVI out there and the temperature on the beach was about 130 degrees F.

       There were no computers on this trip!  All logging was by hand,  with one operating, and the other logging most of the time.  When one person alone was operating, it was quite a juggling act. Note the "small paperweight" used to hold down the log sheets in the sea breeze!
       Most of the operating was on twenty meters during the day.  Forty meter operation at night was tough because we had no way to operate split and had to stay below 7100 because that was the top of the band for us. Than meant no US contacts on 40 meters,  which left a lot of folks unhappy.  A few did call us on CW on our operating frequency which was fine with us, but that apparently did not occur to many.  While we had taken a key with us to operate CW, the QSO rate was so great on phone that we never got around to that.  There was some fifteen meter operation Saturday afternoon.
       Twenty meters was open well into the night with hundreds of US stations worked.  At one point the crowd got a bit boisterous and as we tried to work by call areas, folks were calling out of turn and it was getting impossible to pick out callsigns. At one point we got some great help from Bill, W2ONV who could hear us very well at his Saddlebrook, New Jersey QTH to try to calm the pile down a bit.  The fact that we were running only 100 watts to a vertical made things a bit more difficult because the roaring hoard could not hear us under the thunder of the pileup when we tried to answer someone.  It was incredible!
       The next day, about mid afternoon, something happened that I will never forget.  We were working mostly African and Asian stations on 20 meters and in quick succession worked HS4, XW8 and A2C stations, then a few YU's. Callsigns were in the log that most of us would have lusted after at our home QTH's.  A few minutes later the XW8 called again to say we were still very strong there and that " it must be nice to have an exotic callsign like that"!  Whoa!!!
       That Saturday and Sunday morning were a blur.  Again, compared to the big DX-peditions of today it was really small potatoes but it was a real trip for us. Sunday was packout day for the return trip. Because of security concerns and our military curfews for being on the road, we had to be back on the mountaintop before dark Sunday.  Travel on roads outside the city after dark was prohibited.
       The trip back up the mountain was something.  It was hard to believe that it had come and gone.  The biggest thought was how we would ever top this later in our ham careers. This fear was pretty much allayed the very next time we were on the air from the club station and the pileup on the ET3 callsign was still heavy by anyone's standards.
       The one disappointing thing was that the trip did not count as a separate country.  The IOTA or Islands on the Air program was either in its infancy or not begun at the time. But still, it was quite something to hear and HS4 and XW8 calling us at the same time!
       There had been no major problems after the early problem with getting the generator started. Oil consumption was a little high and we went through our spare cans, but the boat captain leant us enough to keep the generator going through Sunday morning.  We ran out of beer Saturday about midday.  But the fresh fish cooked on the beach over driftwood was fabulous.  And if it got too hot behind the radios it was just a quick run across " hot sand, hot sand " for a dip in the Red Sea to cool off.  What more could you ask for??
       But if there were fears that this little experience would leave us jaded to any "ordinary"activity in the future have proven groundless. There is still the same thrill of working a new one today, the adrenalin still pumps during the CQWW DX Test and there is still the same thrill at hearing a JA on 80 or 160 meters as the first time.
       If nothing else, the experience gives some appreciation for those who go on the truly difficult trips, spending thousands of dollars to put some rare spot on the air.  The thought that what they are doing is many multiples of what we went through that time brings that about.  It also brings some appreciation for what folks on the other end of the pileups go through.

The Loop Project

       I have mentioned the use of loops in the past under the heading " Loop the Loop".  This past week in one of my Facebook Groups there was a question about Low Frequency Reception and the use of loops.  I posted a picture of a loop my father and I built and since there was considerable interest in the group I thought I would put the information here.
       This loop was build back in 1990 and has seen considerable use.  It is a box loop or some would call a solenoid loop that is three feet across and tuned with a three gang variable capacitor. It tunes form roughly 180 to 1500 kHz.  By tapping the coil and selecting one, two or three gangs of the capacitor, the tuning range can be varied.
       A tuned loop is actually a very simple device,  with the difficulties being not in the electrical design but in the mechanics.  This loop was made of wood and designed to be rotated in azimuth and tilted in elevation.
       To keep the loop from tilting over,  my father who worked with me on the project,  made the base from a salvaged solid core door.  Now it must be mentioned that this loop is not small and is not light.  The base must be heavy to make sure the loop is stable and will not fall over or try to move when its turned or tilted.
       The basic idea of any tuned loop is that it consists of a parallel tuned circuit.  The loop is actually the coil part of an L-C circuit. It resonates at the frequency for which it is being used.  A variable capacitor connected across the winding takes care of that chore. The one thing that is important if deep and clean nulls are to be obtained is that all connections should be very short.  For that reason, we chose to mount the variable capacitor right in the center of the loop itself. This is not a remotely tuned device ( one must  often chose between convenience and performance!!) It should be noted that no other connection is made to this parallel tuned circuit.  It stands completely alone.
       The connection to the receiver is made through a two turn link wound a couple inches away from the main winding and connected to a short piece of coaxial cable that then runs to the receiver.      A simple loop could be made simply by winding wire around a cardboard box or a plastic trash can and connecting the capacitor across the main winding and the link winding to the receiver.  I have used similar arrangements many times,  but this project came about with a desire to have something permanent and nice looking.

This is the loop sitting on a table in the back yard of my home.  The cross arms are three feet in length, with wooden plates on the ends that support the windings.  Additional wood pieces around the edges prevent the tension of the wire windings from puling the loop out of shape.  This was a feature that was added after that problem showed up and resulted in an almost complete redesign of the antenna!

 

       This view shows the mounting of the variable capacitor in the center of the loop. An alligator clip allows connection to one, two or three gangs of the capacitor as needed to change the tuning range.

                                                                             

 

This view shows the windings...In this case there are thirteen turns on the loop.  They are spaced about a quarter inch apart.  The two turn link is to the right.

 

 

Another view of the loop in my back yard looking toward the house and showing the tuning capacitor.

 

 

Another view of the loop with my forty foot vertical in the background.  This loop is a little large for permanent use in the house at my location, so I generally use it when operating out in the yard at this table or portable at other locations.  I have used it with a Radio Shack DX-440, My Icom R-75, Hallicrafters SX-96 and my MacKay low frequency radio.  I do not seem to need a preamp with it.  I have used it portable at Galveston and at various locations in the Texas Hill Country, usually just trying to find an electrically quiet spot. It has brought in NDB's from all over the United States and Canada, several from Cuba,  ZBB from Bimini, many from Mexico and Central America and even some from South America,  best NDB DX being from Ecuador.  I have also received broadcast stations from Europe and Morocco while visiting at Galveston.  I have found that the ability to null interfering stations to allow many stations otherwise unloggable being captured. It also helps in nulling noise. The lobes are much broader than the nulls, which are very sharp and deep,  I can totally eliminate local broadcast stations with it. Tilting the loop in the elevation plane can also allow reception of stations at different distances in the same azimuth direction. Tuning of the loop is very sharp, especially on the lower frequencies.

 

 

My First Shortwave Receiver

       Everyone will always remember the first receiver that took them into the shortwave bands. I found mine in storage at my folk's house this week, retrieved it and brought it home.  I thought it would be interesting to share what got me started.
       It was a homebrew receiver built from parts that had been part of lab experiments that came with a radio-tv repair correspondence course that my father had taken in the early 1950's.  It was, in fact, watching him solder and work on assignments that first stirred my interest in radio.
       After he completed the course, the materials, including parts and printed lessons were stored away in a closet and when he figured I was old enough to know what to do with them,  I was given the boxes of goodies. I was eleven years old at the time and already DX-ing with table radios and had begun poking around in them, trying to improve performance and hoping to get something going that would tune the short wave bands.
       Among the boxes of parts and papers there were chassis with holes punched and chapters on designs for various circuits used in superhet receivers.  It was a matter of putting the pieces together to get the receiver transferred from sections of lessons to being an operating radio.  There was one experiment that detailed making an H.F Converter to tune from about 6-18 MHz that would convert those signals to be tuned in by a regular broadcast receiver tuned to just above the high end of the broadcast band. That design became the front end of my first receiver to tune higher than the 160 meter amateur band ( I had previously gotten a standard broadcast receiver to go that high by pulling out the tuning slugs and loosening the trimmer capacitors as far as they would go).
       With the help of the head tech and owner of Lawson's Radio and TV repair shop I managed to get the thing assembled and working. I am not sure how many times I had the chassis in the basket of my bicycle for the two mile ride from our house to his shop, but with his help and parts from his parts stash and junk box,  the radio became a working reality.
       The basic radio was a six tube superhet that tuned the broadcast band with one RF stage and one IF stage.  It had an AC/DC power supply with a double section capacitor and choke filter.  The RF stage was modified with a double tuned input aligned to 1650 kHz with another fixed tuned circuit on its output.  The HF converter consisted of a 12K8 pentagrid converter circuit with its own filament transformer supply that lifted B+ voltage from the basic radio.  The converter had its own two gang variable capacitor with the original radio set up fix-tuned to 1650 kHz.


      

Front and top view of the chassis of the receiver. The main broadcast band tuning capacitor is behind the large drum to the left with the HF converter variable capacitor that provided tuning for the short wave range is on the right. other controls volume, tone and power on-off switch.

Top view of receiver chassis At top left is the edgewise S-meter.  This was actually a milliammeter reading plate current of the 455 kHz IF amplifier stage.  The stronger the signal, the greater AGC voltage applied to the stage and resulting in lower  plate current for the 12SK7 IF amplifier tube.  Thus the S-meter actually read backwards.  The stronger the signal, the lower the plate current indication. To make the meter read correctly,  it was simply mounted upside down! The glass tube to the upper right is the 35L6 audio output tube.  The metal tube to the upper left is the 12SQ7 triode-dual diode tube that served as detector, agc and first AF amplifier.  The glass tube at mid rear of the chassis is the 12SK7 455 kHz amplifier.  The metal tube behind the upper variable capacitor is the 12SA7 Second converter stage. The metal tube below the upper variable capacitor is the 12SK7 RF amplifier for the original BCB set redesigned with fixed coil tuning that became the 1650 khz IF amplifier stage. The glass tube at the rear of the main chassis is the 35Z4 rectifier tube. The metal tube with the grid cap connection above the lower variable capacitor is the 12K8 first converter. The lower variable capacitor tuned the HF converter and was the one used for selecting the shortwave frequency desired.

 

Under chassis wiring of the receiver. The HF converter chassis is to the left.

Close detail of the upper part of the HF converter stage showing the 12K8 Pentagrid Converter tube, the variable capacitor and the input tuning coil.

 

Closer top view showing the chassis top near the tuning capacitor for the base BCB portion of the receiver. The coil to the left of the larger variable capacitor is part of the fix-tuned 1650 khz IF circuit.  The two silver cans are the electrolytic power supply filters. The clips on the rear of the chassis are the connections for antenna and ground.  The small transformer on the rear of the HF converter chassis is for filament voltage for the 12K8 converter stage. The other six filaments are in series and operate like a conventional  AC/DC receiver.

 

Under chassis detail of the HF Converter stage. The large coil is the oscillator coil for the 12K8 pentagrid converter. The small coil to the upper left is one of three tuned circuits between the converter and the rest of the receiver tuned to 1650 khz.

Detail of IF amplifier stage showing the home made IF transformers. Windings were taken from discarded IF transformer cans, slipped over wood dowels and mounted horizontally to allow them to be placed farther apart than originally made to provide looser coupling in an attempt to get better selectivity.  Fixed regeneration was also introduced into the stage to improve selectivity of the stage. Tuning was accomplished with mica trimmer capacitors below the coil and reachable by screwdriver through holes in the chassis from below.

The receiver was not the highest performing beast on the planet,  but it did provide me with a method of listening in on the hitherto un available shortwave  frequencies.  It served for about three years as a way to explore my new world.  I learned a lot about receivers from the project.  In later years, I learned a lot that could have been done to improve it, including such things as converting the AC/DC supply to a transformer supply, which would have required another small chassis to handled the transformer. Voltage regulation could have improved stability.  A manually tuned preselector  could have eliminated the aggravating images that appeared on some places on the dial.  The addition of a 1650 khz crystal between the two tuned circuits between the converter and the rest of the receiver could have greatly improved selectivity. The addition of a beat frequency oscillator could have improved cw reception that was obtained in the original by simply increasing the IF regeneration until the 455 khz stage went into oscillation.  And a Q-multiplier added to the 455 khz IF could have finished the job of making the tuning really sharp.  But that is probably just day dreaming " what-if's"...though to this day I wonder how it would have turned out had I known that at the time and actually made it happen.  In any event,  this receiver which probably looks a little crude to most was the source of many great hours of listening and adventures in the wilds of the short waves.

 

 

Is the Band really Dead? Ten Meter Test and More

       I hope this edition will not be two disjointed because it will cover multiple points, but at least as I begin to write, they are all connected.
       This past weekend was the ARRL Ten Meter DX Contest. This is not one of the " Biggies" but is one that is usually lots of fun and almost always provides some surprises.  it is also a good one for SWL's because it is both phone and CW on the same weekend,  meaning all can tune in and experience some of the same prop( any many of the same stations) whether they copy CW or not.
       For hams,  having both modes on the same weekend gives activity even when the band appears to be " worked out", because when one starts running into the same stations with no new ones, one can just go to the other mode.  Its also fun to run into the same station or ops on both modes because all of the other guys are doing the same thing.
       Which leads me to the question in this edition's title: " Is band really dead?"  I never cease to be amazed by ten, and to a lesser extent, six meters. I so often hear or read on internet posts that the bands are dead and that there is nothing to hear,  but upon tuning slowly and carefully, often find there is something there.  There are times on ten meters particularly that when I hear no activity from operators, I can tune up into the  " beacon band" ( roughly 28180-28300) I can hear the QRP beacons identifying their little heads off.  The band is open, just nobody's home.
       Sometimes I think for hams,  the band being dead becomes a self fulfilling prophecy as a result of folks expecting the band to be dead and not even checking it. Also, even if the band is inactive but open for the beacons, nobody finds anybody because all are just listening.  This is one time that the idea of " listen, listen, listen and THEN call" should be abandoned, When the beacons are in and the background noise is up a bit, then is the time to call CQ, not just once, but several times.  It might also be a time to self post one's self on DX Summit to try to attract attention ( though some might discourage self posting this might be an exception)  If not wanting to post yourself,  at least pot beacons being heard.  Either might attract other folks, maybe even DX, to the band.
       In either event, it was with a little trepidation that I tuned up on the band Saturday morning. But I should have known that there is nothing better to open a "dead" band than a good contest.  At 1352 GMT ( 0752 local CST) I immediately ran into HT7C coming into Central Texas at 28019.3 from Nicaragua with a pretty good signal. Only minutes later, a Special Event station from Chile was in at 28005.5 XR90IARU.  The morning was filled with logging Central and South American stations. Interestingly, North American stations were absent.  I could hear the South Americans working them, but they were for the most part inaudible here in Waco.  I did hear K5NA, but that signal was obviously coming in via backscatter.  One European, YT9X from Serbia, propped in at 1444 GMT.
       About  midday, things got a bit more interesting.  Stations from  Eastern Canada began to come in, but the band also opened to the Pacific.  Beginning shortly before noon, several Hawaiians were heard along with the catch of the day, 5W1SA from Somoa who was audible most of the afternoon with signals ranging from S-5 to S-9. No Australians were heard but did hear ZM1A from New Zealand on 28040 at 2227 with a signal just above the noise. About 2315 ( 1715 Local CST) the band snapped shut like the slamming of a door.
       Sunday was almost a repeat, with the exception that by mid morning many US stations were heard.  By noon, a few African stations were coming in, including 6W1SR from Senegal  at 1846.  A couple South Africans were heard.  I am not sure if the band was not open or this particular contest just did not attract that much attention from the continent. I heard US stations working Europeans but heard few myself.  Once again, there were numerous Hawaiians coming in.  By noon,  the Northeast US stations were booming in with amazing signals, quite unlike the day before. Many pushed the S-meter will above S-9.
      All in all, a band that was supposed to be dead was simply unoccupied until the contesters showed up.  I think many times hams, who as a group should know better, don't check the higher bands because they might take a look at some of the Facebook pages and see postings of "bands terrible" and don't turn on the radio.  Some may even fall into the trap of thinking that we are on the down side of the sunspot cycle and the bands are expected to be bad. Sometimes even DX Summit can give one the feeling that nobody's home.  But if we all do that, nobody will really know that the ionosphere is there waiting to be used! Besides, someone has the be the first to post something to SX Summit!!
       The same goes for SWL-ing.  I have really enjoyed the Facebook groups I have discovered in recent days.  They members are fun, they are sharing the love of the hobby with several diverse interests showing up.  With members in different parts of the globe, it is particularly interesting to read about prop from " the other end of the path."
       But often, I will notice posts of " band dead, hearing nothing," or that one of the usual strong band occupants of 31 meters or some other band is not there. You can almost hear the disappointment and the feeling is that the poster will go off and do something else, perhaps missing a real nugget!
        There are times when some of the semi-local stations like Radio Havana, WRMI, WBCQ and others may be weak, fluttery, or almost non-existent.  But then is not the time to turn off the radio and turn on the TV! Before doing that, it is a good thing to check around and see what else is going on down " in the weeds".
       When I see that posted on the groups,  the first thing I do is go check the WWV frequencies.  If on 10 and 15 MHz WWV is weak but WWVH is strong or even covering it, the band is far from dead...just open really, really long! Then is the time to turn on the BFO and start trolling 31 meters for carriers,  then when one is spotted, go back to the AM mode and try to pull something out. Chances are, down in the grass will be a fluttery signal that will have the S-meter dancing a bouncy dance or maybe not even moving.  There those of us in North America will find regional Chinese stations,  All India Radio long path, Vietnamese stations, maybe even some of the big boys broadcasting to somewhere other than North America.  If a semi local station is weak and fluttery or marked with echo, chances are you are hearing it back scatter or multi path. That is not the time to turn the radio off,  but instead time to fill the coffee cup ( or other drink glass!) and pull on the headphones and pull out some new ones!
       If the upper bands are not showing much, keep dropping down to lower and lower bands until you find something.  I usually start the evening with a sweep of the WWV and CHU frequencies and end up with a de-facto prop chart in the log.  A look at the signal strengths for WWV,  WWVH and CHU on 2.5, 5, 10, 15, 20 and 25 MHz and 3.33, 7.68 and 14.67 MHz respectively  gives a pretty good picture of what is happening on the bands.  Then I start with the higher bands and work my way down until I start finding the goodies.  Sometimes a weak signal from WWV does not indicate a dead band, but one that has its legs stretched out long. ( at least for here in Texas...at your location, things might be different but you can learn over time what it all means)
       One of the other things I have noticed in the Facebook groups, particularly among relative newcomers to the hobby,  its the notion that a simple short piece of wire thrown up along a fence or around a room is adequate for listening.  In a way that is true, at least for casual listening to the power house stations targeting your listening area.  Others in the groups will post suggestions that such is all they need,  and that is true up to a point.
       However,  I think this leads to some of the disappointed postings about the bands being in poor shape. If signals are just a few DB above the local noise level,  if the bands take a shift,  those signals might drop below the threshold of what that indoor or low horizontal wire might be able to deliver above the local noise. Or, a low horizontal antenna might not respond to DX signals arriving at a low vertical angle.   For the new guys,  I would suggest that that for beginning, those kinds of antennas are good for getting your feet wet,  but nothing beats a good outdoor antenna at a decent height.  Old CB antennas can deliver pretty good signals from stations pushing over a million watts of effective radiated power toward you,  but won't do much for hearing a 10 kw station from Africa or Asia if you are in the US. The problem is not sensitivity of the radios, with many of the new ones having really good sensitivity.  Its the ratio of the desired signal to the noise.  Getting your antenna away from the noise and having enough up there to have a decent amount of voltage induced in it by a passing signal is the true answer. 
       And the oft forgotten part is the all critical angle of radiation.  A low, horizontal antenna will respond most to signals arriving at a high angle. Some low angle signals will be heard, but there will be a much weaker voltage induced by that passing signal. Horizontal antennas higher off the ground will respond to lower and lower angle arriving signals. A wire in the clear and not running though tree limbs or foliage will do much better.  Wires running through trees also suffer the danger of having noise picked up by the trees that may be near power lines with other parts of their canopies.
        Vertical antennas or inverted L's will also do much better with the low angle arriving signals.  The ionosphere acts according to the same laws of physics as does a mirror.  The angle of reflection equals the angle of incidence. Signals from a greater distance arrive at a much lower angle than nearby signals. 
       Often when a given band is just about to close, the effective height of the ionosphere is the greatest,  meaning that signals from a greater distance will be coming in. This means that being there for the opening and the closing of a band might be the best time for getting the real DX!
       Speaking of the web, Facebook groups and other things,  a big thank you goes out to Bob Padula in Australia for accepting my article on receivers used through the years and posting it on his excellent site The Mount Evelyn DX Report at medxr.BlogSpot.com.au    I think I have links he posted there for many of you finding this site.  The increasing number of DX groups brings a new aspect to the hobby, including the sharing of what is going on in real time.
       As always, I welcome comments and other ideas for articles and even DX tips.
       73 and good DX!