Can real DX Be Heard on a Regenerative Receiver

In an earlier episode,  I told about the somewhat unplanned project to build a regenerative receiver.
It was done out of a desire to see how such a radio would have performed if I had had one when I was a young kid.

The project had a regenerative detector and two stages of audio and included bandspread tuning and was expected to tune about 6-18 mhz.

The first night it was finished,  I tuned through the dial just to make sure it was working and to get some idea what frequency range it actually tuned.

It ended up being a couple of days before I was able to get back to the little radio,  with things coming up at work and household projects that had to be taken care of.

The first test run had shown that the radio worked and a couple maritime cw stations along with a broadcast station or two and time signal station WWV were heard.

A couple days later,  I sat down in front of the rig with it actually set up on the desk as it would be used,  rather than turned on its side with test leads connected and tools and such scattered all over the place.

The first step  taken was to get a better idea of what was where on the dial,  which was only calibrated 0-100.  I had already found where 10 MHz was because of WWV and where 9420 was from finding the very well known Greek broadcast station. It was decided to use my ham transceiver to get a few more calibration points.

I put my Icom 720 on a dummy load and had the drive turned all the way down to provide the test signals.  Then calibration points were found for the bottom and top of the 40, 30 and 20 meter ham bands.  Tuning up from the mark for the top of 20 meters had me running into the 15 MHz WWV which gave another calibration point.

Going down the other way, the radio did not tune down far enough to reach the 5 MHz WWV.  In fact,  the bottom of the 40 meter band just did make it within the tuning range of the radio,  and the 49 meter shortwave broadcast band didn't quite make it at all at first.  By turning the tuning slug all the way in on the input coil,  only a portion of it could be reached.

I spent a little time getting the feel of the controls tuning through the 20 meter cw band.  It seemed that the most stable point for copying cw without overloading the radio was with the regeneration control set just barely past the point of oscillation.

It being early summer,  twenty meters was still open with lots of signals even at just before sundown.
It was obvious that the selectivity was not going to be as good as the Icom or my FT-101 with its 200 Hz cw filter.  It might prove difficult to pull out weak signals from DX stations in a crowd.

But then,  it must be possible,  because in the early days of hamming,  regenerative receivers were all many ops had....and they did work DX.  But were the bands as crowded as today? No way to know.

So it was down to tuning. Starting high in the cw portion of the band,  I immediately ran across a strong station that could only be one thing from the content....it was an ARRL bulletin.  It seemed somewhat appropriate that one of the first ham stations in the log from the little receiver would be the ARRL Club Station, W1AW !!!

Going on down the band netted a number of US stations,  but there was still hope for some DX.  The little rig did not disappoint.  It took some very careful juggling of regeneration and bandspread controls,  but soon I had confirmed an ID for OA4CWA from Peru!

I was pretty happy with that,  but there would be a few more.  Within the next half hour I had logged OM3KFF from the Slovak Republic,  IK3HZK from Italy  and F1MCC from France.  Not rare DX by any stretch of the imagination in the eyes of big time DX-ers,  but I felt it was pretty good for the little regen rig.

A quick run down to 40 meters did not yield quite as spectacular results.  Stateside signals were much stronger and it was early in the evening.  I did identify K4DMT, W0RFN and KA9KWR. I was anxious to try a run through the maritime cw band at 8 MHz,  but did stop on one last station that could be considered DX I suppose,  KP4/W8HNI from Puerto Rico.

The maritime cw band was a real bit of an adventure,  but in some ways was a little easier,  first from the standpoint that the stations generally ran more power than hams,  and also because they were not piled on top of each other helter skelter and were easier to separate.  In about 45 minutes I was able to put several of them in the log. Those pulled out included the following:
PJC Netherlands Antilles
FLBA ( being a four letter call apparently a ship as opposed to a shore station)
NMC
WNU Slidell, Louisiana
FUF  Guadalupe Island
WNU-33 Slidell
WCC Chatham, Mass.  ( probably the best known of the shore stations of the day)
ZSC Capetown, South Africa
VCS  Halifax
FFL St Lys Radio,  France
DAN  Norddeich Radio, Germany
OST4  Ostend Radio, Belgium
HPP  Panama
CLA  Cuba

Not bad stuff for a junk box regen radio.

( And another good reason for keeping logs.  Then and now I log virtually everything I hear each time I hear it and have kept logs going back to 1957)

Over the next few days,  I played around with some things trying to overcome the overload and pulling that occurred with some stations.  I ended up putting a 100 pF variable capacitor in series with the hot lead of the antenna to provide a little decoupling at times.

It may seem perhaps sacrilege but at one point I brought out a little MFJ tuned preselector and put in front of the input.  It was not so much as to provide gain for weak signals,  as there was really no need for that.  It did seem to provide a little " cushion " between the antenna and the detector and let it see a more stable load on the grid circuit.  Most of the time the gain control on the preamp was kept very low.  The additional selectivity did seem to help.

It is unfortunate that other things got in the way of spending much more time on the little rig.  Field Day was coming up and a local group was planning to operate at a nearby park and attention got diverted from it.

After Field Day,  pieces for a 10-meter beam were picked up and the design and construction of the yagi got my attention,  working out the details of maximum gain,  optimum wide spacing of the elements,  then getting it on top of the 40 feet of Rohn 45G that had grown outside the shack at my folks house ( my dad,  who is now a silent key and I had a joint shack for a time when I lived in an apartment and before I moved to my current location across town with my own real yard and future antenna  farm)

After that it was more projects,  overtime at work, and other things and the little radio got put on the shelf.  Now almost thirty years later, it sits dust covered in my back yard shop.  Perhaps its time to dust it off, re cap the power supply and bring it into the indoor shack and give it a chance to pull in some more DX.

Thinking about it still brings back the says of yearning for a Knight Ocean Hopper or Span Master.  It  would be nice to find one and spend some time twirling the dials,  but unfortunately they are not great in number any more and the collectors seem to snap them up and put them on a shelf,  not leaving many to be found by us old geezers who would just like to spend some time with them finding adventure.

A Trip Back in Time

I think we may have all done this at one time or another. We've sat in front of our quasi-modern rig and thought back to days before we had such nice gear,  wondering if knowing what we know no we could have landed more DX with older,  simpler gear than we have now.

There is also the desire perhaps to have a chance to get the receiver or transmitter that we wanted then.  It might not be a matter of thinking the gear would be better than what we have now,  as much as a curiosity of finding out if it was as good as we thought it might be.

From experience at picking up some of these rigs at hamfests,  I have come to learn that sometimes this is true and sometimes not.  The gear might be better than we had  " back then" but sometimes we learn that perhaps it was more a matter of learning how to use radios better that has lead to more DX.

I have often longed for one of the old Knight regenerative receivers that I wanted so bad as a kid.  I never got one and ended up with what was probably a better receiver for a first SWL rig anyway ( a kit from a radio-tv correspondence course my dad had taken) That radio was not without its own frustrations, including very broad selectivity, almost no image rejection, and a level of stability that almost required keeping a hand on the tuning knob while listening to a station for more than five minutes.

But the urge to find out just what might have been struck rather hard one day in the early nineties as I set in my quasi-modern ( i.e. less than twenty year old) rig  during a stormy afternoon.  The static was so bad that listening was like having a little man inside my headphones delivering blows from a little sledge hammer directly onto my eardrums.

Thoughts turned toward a construction project,  perhaps a regenerative receiver knowing what I know now and seeing if any real DX could be heard with it.

At the time I had a pretty well equipped junk box ( ok, more like a junk closet) full of various parts, transformers,  salvaged chassis and other goodies,  along with a huge stock of tubes,  I began the search. I already knew what I would start with.  I had picked up a chassis and front panel that had been somebody's home brew project for something at a hamfest.  It had a two-gang variable capacitor of the broadcast type along with a small transformer power supply.  It looked like it might have been some kind of signal generator.  The capacitor had a gear reduction drive on it and there were three octal tube sockets behind the panel and some other holes,  along with a really nice panel light.
The dial on the front was calibrated 0-100,  not unlike what my first SWL receiver had had.

The first step was to strip out everything including the wiring for the power supply. I already had plans for that which included building a choke input filter that would give somewhat less than the 180 volts that came out of it as it stood,  but would also give a little bit better voltage regulation.

The it was decided that I would use a 6SN7 for the detector.  This tube is a dual triode and I figured that I could at least have an audio stage to give a bit more audio to the headphones.

The junk box yielded a collection of Miller factory made coils that I had bought in a closeout at a local electronics store that was closing up. There were coils for the broadcast band, 1.6 to 6 MHz and 6 to 18 MHz designed to be used as input coils tuned by a 365 picofarad variable capacitor.  Since I had had a broadcast band regen set as a kid,  I decided I wanted short wave,  and a range that would give at least a chance at hearing some DX. So the 6-18 MHz coil was chosen.

The only thing was,  the coil had just two windings: a coupling coil meant to go to the antenna and ground,  and a slug tuned main winding meant to go to the input of the first stage.  There needed to be a tickler coil for feedback for regeneration.  I took care of that by winding a few turns of enamel covered magnet wire from the junk box.

I was beginning to get into the deal by this point,  so rather than just scramble winding it over the other windings and taping it down,  I actually used a little shellac to hold it permanently in place. There just happened to be a nice 3/8's inch hole right next to the octal socket nearest the variable on the chassis that would make a good home for the coil,  with the active windings somewhat shielded from hand capacity effects under the chassis.

While the shellac was drying,  I got to work on the power supply.  It was pretty quick.  I pulled a 5Y3 out of the tube stash figuring it would have plenty of current capability for what this little thing would pull. There were  both 6.3 and 5 volt filament windings on the transformer along with the tapped high voltage secondary.  Both filament winders were center tapped,  so this was going to work out nicely.  I had a filter choke salvaged from a scrapped out Silvertone radio that went in place and one of the extra holes in the chassis allowed a for-real can-type filter capacitor to be used, a dual section 30 microfarad job.

Noticing a nice hole the right size for another  tube socket was right next to the filter cap hole,  I got to thinking that while I was part-way to having a nice, stable power supply,  why not go whole hog and regulate it....so a VR 150 went into the spot.  The project was quickly taking on a life of its own. I figured I would send the regulated voltage to the half of the 6SN7 used for the detector and let the other half run off the unregulated part of the supply.

That left one other tube socket empty over near the right rear part of the chassis.  By now the project had grown from an quick afternoon throw-together thing to a four day after work thing.  How about another audio stage so this monster could drive a speaker instead of just headphones.  A quick dig in the tube stock turned up a 6V6 and a plate-to-voice coil transformer that just barely fit on the chassis. ( ok so I cheated a bit,  the mounting tab on one side of the transformer was too close to the edge and it would be held in place by just one screw...don't tell anybody)

All of this set me to wiring up the audio part first.  A quick trip to the RCA Receiving Tube Manual front section led to information on resistance coupling audio stages to match up the second half of the 6SN7 to the grid of the 6V6.  There would not be room for another audio transformer so this would be necessary. 

An aside here,  the RCA and Sylvania tube manuals are excellent sources of design information and info on theory of tube circuits.  They are becoming rare so snagging one at a ham fest is a good idea if you do anything much in the line of building tube-based projects or repairing boat anchors. RCA printed two versions,  one for receiving tubes and one for transmitting tubes. Even without building anything,  they make fascinating reads and there is a ton of true geek material to look through regarding the characteristics of the tubes.  I used these as study material for my ham licenses and for getting ready for the test for First Class Radiotelephone License ( no mere GROL--the real thing) back in the sixties.

There were four holes in the lower front of the chassis and panel that I was using,  so a potentiometer for a volume control went into the right-most hole.  I did not use the AC power switch on the back of the pot because I wanted to keep the AC voltage well away from the detector wiring,  knowing from experience that regenerative circuits can sometimes be susceptible to hum anyway.  This led to one rather unorthodox thing...the power switch was a toggle switch mounted on the left side of the chassis near the rear next to a fuse holder.

Those were the only holes I had to drill in the chassis and kind of went against the original idea of using things as they were.  I really did not want to build an unfused power supply ( NEVER be tempted to do this!!) and did not want to use one of those in-the-power-cord things.

Wiring up the audio stages went pretty quickly.  The volume control was put in the grid circuit of the second half of the 6SN7. That stage was then resistance coupled to the input of the 6V6 stage.
Another trip to the tube manual helped determine the value of a cathode resister for the 6V6 for self bias with a bypass capacitor across it to ground.

Just like in the old magazine construction project articles,  it was decided to test the audio stages before the detector was wired up,  mainly so if things didn't work there would only be one place at a time to trouble shoot.  The power supply was already tested and had about 170 volts unregulated and a nice 150 volts regulated.  A six volt bulb was put in the little pilot light socket already in the panel and the smoke test begun.

No problems.  The whole thing was almost too simple for anything to go wrong,  but you never know... There was only a very faint hiss and no hum ( yay!) coming from the speaker with the volume control all the way up ( grid of the 6SN7 highest above ground) A little finger touch to the center lug of the volume control brought a satisfying growl from the speaker so it appeared all was well.

Time to get to the meat of the project.  I had decided that even with the gear reduction drive on the main tuning capacitor,  it might be nice to have a little bandspread tuning.  A small variable with only three rotor plates taken from some old rig that had been junked for parts was used.  It went in one of the lower front panel holes.

That left the question of regeneration control.  I had decided against using resistance controlling so as not to give too much of a changing load to the plate of the detector while making adjustments to the feedback.  The plan was to have the ticker feedback winding high side go to the plate of the detector through a 100 picofarad capacitor ( plate voltage on the cap through the winding not a good idea with
 fingers near it)with the " cold end of the winding going to the stator places of the small capacitor that would control the feedback.  Since the rotor side of most variables is common to the frame,  that side was going to ground. The shaft of the capacitor was cut short and an insulated coupling and extension used to go to the knob to try to reduce hand capacity effects.

From there,  it was just running the mica capacitor paralleled with a resistor from the grid of the 6SN7 half used for the detector to the top end of the tuning coil,  and the other side of the coil to ground.  The coupling winding went through a short piece of shielded audio cable to a chassis mount SO-239 fitting on the back right side of the chassis.

Then there was a capacitor to couple the plate of the first side of the  6SN7 to the other,  a plate resistor for the detector once again chosen with the help of the tube manual, an RF choke between the low end of that and the power supply to keep from having any RF getting in there and a bypass capacitor to ground for good measure.

Time now for " smoke test number 2." Power came up, volume came up and a little louder hiss came from the speaker as the volume was brought about a third way up. Then the regeneration control capacitor was rotated to more messed and there was soon the expected "plop" sound in the speaker with a somewhat louder rushing sound as the stage went into oscillation. That meant that the 50-50 chance of getting the polarity of the tickler coil connected right was successful.

Now was the time to see if something could be heard. I set the main and bandspread tuning capacitors to mid range and brought a jumper lead to my 80-meter windom antenna over and plugged it into the SO-239,  met with a satisfying crackle and increase in noise.  The raw lead from the antenna was fed into the radio,   not through my antenna tuner as I usually did for the ham rig,  the idea being one less thing to tune to get things to the point of hearing something.

Of course,  I had no idea where I was frequency wise. As I swept the main tuning back and forth,  I ran into some cw signals,  easily identifyable as maritime shore stations ( this was back in the 90's when many were still on the air) The stability was not too bad and callsigns for WLO and KFS were heard.  Perhaps the 8 MHz marine band?  Tuning toward less capacity and thus higher frequency,  I soon ran into several broadcast stations,  marked by whistles as the rig was still in oscillation. Backing off the regeneration control took away the whistle and let the audio of the signals come through. I hit one with rather recognizable music style and rested there a minute and soon was able to confirm that I must have been on 9420 as it was indeed the Voice of Greece,  or as it was known then Foni ti Helladis ( if I remember right ) Tuning up through several stations,  then hitting a stretch of blank space, there was  then the unmistakable WWV.  So the point on the dial corresponding to "70" was obviously 10 mhz.  I was well on my way of finding my way around the dial.

Tuning up a bit further,  I hit as expected an SSB signal.  Tuning these with a regenerative receiver is a real trick.  You have to be in feedback but not too much,  and you have to tune carefully.  Using the bandspread control with a little touch and release as there was still some hand capacity frequency pulling affects,  it was determined that the station was transmitting aviation weather. New York Aviation Weather! There was still significant drift,  but I would never have expected full communication grade stability from this thing.

Tuning up higher,  I ran into the ( still to this day for me) unidentified  radio teletype signal just inside the 30 meter ham band and a few cw signals.

Obviously the thing was working and I had traveled back in time to my childhood...sort of.  There would be more experimentation and some real DX tuning another time,  but it was late and dinner had been missed,  and there are priorities.  I will share more of the DX adventures with the rig dubbed Little Howler II at another time.

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.