Friday, November 22, 2019

How Do You Talk to the Opposite Side of the World with Ham Radio?

It's something that's talked about all the time when people talk about ham radio: you can talk to the other side of the world.  You can, indeed, it's just not always easy or trivial.  Ham radio is regularly referred to as a thousand hobbies with one name, the particular sub-hobby of trying to talk to as many recognized countries as possible, has always been one of my main interests in the hobby.  Other hams out there are recognizing the warning sign immediately, “he's a DXer!”  Yeppir.  Guilty as charged.

There's stuff to unpack in there.  How many countries do you think there are?  That depends on what the meaning of country is, right?  For American hams, the most commonly recognized source of authority on that is the American Radio Relay League, who likes to call themselves the National Organization for Amateur Radio (which is more recognizable to non-hams).  The ARRL manages this through their DX Century Club programs.  (Note that to Shortwave Listeners and other radio hobbyists, the abbreviation DX has long been used to denote Distance and the Unknown).  Part of the rules are common sense: a country is a place under its own government (even puppet countries, like the old Soviet Republics, were officially their own governments).  Where the DXCC list deviates from that common sense is that if one part of the country is separated from the rest by more than 350 kilometers (217 miles), that remote portion is considered a new country.  That means, for example, that Hawaii and Alaska are states in the United States, but they're also separate countries for the DXCC awards!

That means that there are more ham radio countries than countries recognized by other governments.  There are 340 currently recognized DXCC countries.  That includes countries that don't exist anymore, but if you have a valid confirmation (QSL) card from the country, it's still accepted.  For example, at one point, the Panama Canal Zone was a country - I have a card from back then. 

That's just the very edge of that rabbit hole, but I won't go into more.  Suffice it to say that whenever there are lists and recognition that comes from checking off having contacted ("worked") these countries, guys get competitive and go to great lengths to work more countries than their friends.  Lists like the Most Wanted Countries circulate, and obscure, uninhabited islands attract “DXPeditions” to get operators on them for brief periods (typically two weeks).  This was a major operation in 2006, Peter the First Island.  As life works out, I know one of the operators in the group casually - he works in town at one of my previous employers

One of the areas of the radio hobby you'll need to study is radio propagation which tells you how radio signals get from one part of the earth to another.  I've posted on this topic before; this post gives a good summary of the essences and even some of the details of current ham operating.
Probably the thing I find the most interesting in radio is propagation - how the signal gets from one station to the other - and especially the ionospheric propagation.  This can turn into multiple pages itself, but the ionosphere is a layer of the atmosphere where the molecules present in the lower atmosphere are ionized by incoming solar radiation, and the air is so rarefied that it takes long times for ions to bump into something that makes them neutral again.  ("Do you think you're ionized?" "Yes, I'm positive") .  The ionosphere, in turn, is characterized as having several layers, with each layer's name changing with height.  The lowest, densest layer is called the D layer, and as we look farther vertically, they go through the E and F layers.  During periods of high ionization the F layer can further stratify into F1 and higher F2 layers.  The ionosphere expands and contracts, getting taller or shorter with incoming solar energy.

In general, the higher layers are active when the sun is overhead, but even then are dependent on the solar energy output which varies day by day, with the solar cycle, with (possible) grand cycles of solar activities and so on.  Generally, the type of propagation that gets hams excited is from the F2 layer, for a simple reason: it's the highest layer, so signals "reflect" from farther up and can go farther around the world. 
You rarely have the opportunity or need to talk with the exact opposite side of the world.  That's called the antipode and many times, there's nothing there but ocean.  The complication of contacting a station even near the antipode is that (often) the radio signals from each station diverge a bit from a straight line, and arrive at the receiver after varying time delays.  This multipath propagation can distort the modulation and make it difficult to understand the transmissions.

This map from Engaging Data shows a set of crosshairs that are antipodes of each other.  On the left, I dragged the globe around until it was relatively close to my location, and it repositioned the globe on the right to show the antipode.  When we were kids, we used to say you'd dig straight through the earth and come out in China.  Most of the US has its antipode in the South Indian Ocean; China is in the Northern Hemisphere.

It works out that one of the handful of countries I haven't worked that are still on the list is an island near Indonesia in the top of that view.  Called by the awkward name Cocos-Keeling Island, it's an Australian possession and has an Australian callsign - starting with VK9C.  In this case, it's VK9CZ.  Unlike the Peter 1 expedition, which looks like a military takeover of the frozen island, it's two guys on a two or three week trip to the island, which is a lightly inhabited resort.

I don't consider Indonesia particularly hard to contact, but that was when we had sunspots* and I'd work them on 15 or 10 meter bands in our evening local time - early morning there.  One of the first steps is to try to get a competent propagation prediction.  The VK9CZ guys provide access to customized maps for your location, provided by this site (I believe).  I get this:

You supplement these predictions with the presence of GrayLine propagation enhancement (most important on 7 MHz and down and vitally important on 1.8 MHz (160meters)) which happens at local sunrise and sunset plus or minus a bit - perhaps as much as an hour.  The GrayLine would add higher probability colors perhaps red or orange on the bottom row (80 meters), at 12 and 19 horizontally.

This prediction shows that 15meters will have great propagation to VK9C at 15 or 16 hours UTC, the deep orange or red squares.  That's 10 or 11 AM here and makes some sense - except for the fact that they're almost perfectly 12 hours out from us, making that well after dark on their end and those are daylight bands.  So far this particular propagation prediction chart has been pretty useless.  This morning I was up at 6AM for the sunrise GrayLine.  They were on higher frequency bands but since they're having a really hard time working the US, they dropped to 80 meters.  I listened from about our sunrise at 6:50 until about 7:30 and never heard any signal I could identify. 

I need some more study of the band openings.  Mostly, I need some luck here.

* I have plenty of posts that mention sunspots and how higher sunspot numbers correlate with higher solar activity and better propagation, but nothing on that topic by itself.


  1. Wow. Here I thought you just needed to shout into the mic, who knew? :)

    1. There was a cartoon I remember vividly, and can't think of the guy's call. He was talking about doing work in the garden and one of his young kids was shouting into a flower, "You're 5 by 9! 5 by 9!!" I searched a little but image search just wasn't getting it for me.

  2. Well done, SiG.

    I've always been more of the experimenter sub-group. I'll build things, make them work, and either build an improved one, or move on to something else.

    And I like boat anchors, too. Got a few on the shelf that I need to go through.

    And then there's satellites. And Rag Chewing. And chasing counties. And handling traffic, and.....

    Yep, Ham Radio sure has a lot of neat stuff to offer.

  3. Enjoyed your post. I have never really found my niche in Amatuer Radio. I like to piddle around with the hardware. I enjoy the "conesting" of Field Day but have not particpated in any other contests.

    Recently, I have developed an interest in satellites. I fixed the PIN switching in the 2 meter front end of my IC-821H. I am re-learning C programming to update the Hamlib driver for the same radio (it is still alpha status). I need to build an Eggbeater or similar fixed antenna since I don't have an Az-El rotator.

    SiG, they are trying to get to Bouvet again this winter. Have you got that already?

  4. SiG, they are trying to get to Bouvet again this winter. Have you got that already? No, I don't. Their last attempt is what got me to build my small receiving loop. With some months of actual experimenting, I find it's hit or miss on if it works. The results would be better if I had a couple of acres and a steerable array.

    I could write a volume on some of these last dozen or so countries (I think I'm at 312 worked). Some of them have been fairly easy, which means propagation there is routine, there's just nobody there. Some of them, like Heard Island, have been very difficult. (I still call it Barely Heard Island). Looking back on the Peter 1 expedition from 2006, I have much more respect for how well they set it up and pulled it off.

    As for finding your niche, I didn't expect to become a DXer when I started, but gravitated toward it over the years. I'd get into the big DX contests (this weekend is one of the big ones, CQWW CW) just to work new countries. None of them mind it. I've experimented with a lot of digital modes, from old ones like RTTY and slow scan TV to Olivia, and and the "new hotness": FT8.

    I started out listening to shortwave radio and people always used to ask, "how far can you hear from with that?" With ham radio it's "how far can you talk?"

    1. Picked up some juicy DX on 80 this weekend, may get some more later today on 40 and 80. Even worked some 160 DX earlier this week on my 6' high 160 NVIS antenna! (admittedly that was the Carribean, so not really long haul, but still...)

  5. My experience is that there are often more openings on the upper HF bands these days than folks on the band; since "everyone knows" that 15 (or 12 or 10) is dead these days, nobody operates there and nobody posts a spot. It is amazing how quickly a band can heat up once somebody spots some DX on the upper HF bands. A good way to spot an opening is to listen on CB. When the South American stations are booming in, then 12 and probably 10 are open.

    Similarly, since "everyone knows' that 160 is useless during the day, nobody is there. I've done tests with friends and made short-skip contacts with less than 5 watts CW and 10 watts single sideband. But according to some, that cannot have happened, since "the D layer eats 160 signals during the day!" I've worked 50 miles away (NVIS or short-hop skywave) on 80 meters during the day with half a watt. Got a 579 signal report.

    I've picked up some juicy DX by just listening on the bands few are listening to.

    1. WSPR is pretty good at spotting band openings. You might have to use a digital mode to make contacts on that band, but at least you can tell if it's "open" or not by watching the on-line reporting sites.

    2. I wasn't clear enough on the role of listening, and comparing the predictions with what you can hear, but that's really important. There used to be saying that you should listen twice as much as you call because you have two ears and one mouth. I think it's more like listen 5 or 10 times as much as you call.

      I grew up on 15 meters as a novice. Something like 25 years before the advent of even the earliest bulletin boards for checking spots.

      This afternoon in the space of about 30 seconds, on 30 meters, I copied Australia and South Africa. For me, that would be roughly 90 and 270 degree beam headings - if I had a beam for 30m.

  6. Timing for this article is great - I had the unexpected pleasure of working VK6APK, just yesterday, on 20 meters. I was using a half-wave wire hanging from a fishing pole at an RV park in Bushnell, Fl. And the QSO was confirmed on LoTW. (So it really happened!) QRZ says the distance from here is 11338 mi.

    I'm looking at your chart above, and my QSO was at 2251Z, from here in EL88, and it says what, 10% or 20% chance?

    If in doubt, make the call. Maybe you'll get that elusive DX.

    73! and good DX. de KZ1O

  7. So, you made me curious, and I went to the VOACAP site and did some digging. Short path this time of year is a bust based on both VOACAP and my assessment of the FoF2 over the North Pole which is too low to support an MUF of 14 mHz, IMHO. Long path, which goes over the South Pole, may be a better bet. Mid Atlantic, local sunrise and local sunset are a better bet, preference to sunrise, but I may listen on 40 and see if I can get lucky.

    1. I think you're right about long path/short path. I just don't have any way to steer North vs. South below 20m. On 20m, I have a steerable antenna but VOACAP says the best shot is 17m at 13z (8AM EST) and my observations have been that they've been operating on lower frequencies (80 or 160m) around that time. They have about an hour or 90 minutes 'til dawn (by eyeballing the gray line maps) and they'll be on 20 after dark here.

      Whenever you're dealing with a station near the antipode, you get skew paths that don't fit our mental models well. Those are the ones that add the delayed signals that spread out the RF in time, and makes it harder to tell a dah from a dit.

      40 was sounding fairly good well before sunset yesterday, around the time the VK9C guys were on that band, but I still never copied them. I think I'll have to spend the next few afternoons into the evening until they shutdown - scheduled for Friday.

    2. I heard VK9CZ last night at gray-line on 40, but they were right at the noise level and never were solid copy. I did not transmit.

      The night before, they were up and down, but with good timing a QSO was possible.....right up until a lid, who shall remain nameless, had his computer send repeated strings of his callsign 5 or 6 times. Right on top of VK9CZ. After that, no joy.

      That morning, I heard them about S5, about 20 minutes after sunrise, grayline, on 30 meters. Tried for 10 minutes until they faded, no joy.

      Although I did not work them, I take some satisfaction that my modest all wire beam station was capable of hearing them. I got a real thrill out of picking them up, which is why I'm still listening after more than 50 years. I hope you had better luck than I, SG

    3. I heard them several times over the last few days, but never got them in the log. Yesterday, their website said they were taking down the station by about 0100 on the 28th, which was 8PM EST on the 27th, so I'm surprised they were on 30 this morning. I couldn't have tried anyway, with my trip to South Florida.

      A couple of days in a row, I'd heard them on 40 from about 2315/2330 to just after 0000Z, and one night heard them on 30m FT8 until closer to 0200Z. Last night it was 40 SSB and I called but never got around/through the pileup. Depending on the setup, your wire beams may be better than my antenna. Mine is an 80/40 trapped vertical. (Cushcraft MA8040V)

    4. They were on 40 yesterday PM, and the day before; Monday AM I heard them on 30. My upper HF antenna is Lazy H cut for 30 meters; it works well from 40 all the way to 6 meters, but peaks at 20, 17 and 15. I tried the skeleton conical version, which loads easier on 17 and 15, due to the lower Q. Midpoint is about 45 ft up. gain is around 12-14 dbi, or about 4 to 6 db better than a dipole, depending on the band.

      I heard them on 40 on my broadband dipole, which is about 55' up; it's got about 7 or 8 DB of gain. I do have a 3 element wire YAgi-Uda for 40 meters, but have not put it up since we used it 3 Field Days ago. With the last windstorm I now have an open hole in the trees in which to put it. Maybe this winter.

      I currently have beverages up which make a big difference in being able to pull in signals. Listening antennas like the BOG which are 3 of my beverages make a huge difference in SN ratio and the ability to pull stations out of the noise. I could copy them on 40 only with the BOG; without that the noise was too much.

      If you are going to run a vertical on the low bands, you DEFINITELY need a listening antenna. If you haven't room for even a BOG, which needs only 150' to be effective, then I'd suggest a look at a K9AY loop, or one of many others.

      Warm regards,

    5. I have a "Mini K9AY" loop that I scaled to 1/4 size, specifically to be scaled to 40 and 30m. (design details here and results here). I found it helped with some noise but not enough to pull the signals out. Every time I did an A/B test compared to my vertical, signals were better on the vertical. It matters most when the signals are barely peaking out of the noise.

      Does the BOG have to be 150' long in one straight run? I'd have to run it into the yards of a neighbor or two.

    6. No, a BOG or Beverages in general are tolerant of deviations from the straight line. You can makes it shorter than 150', too, especially if you are running it on 40 and 30. The difference between a Beverage above the ground, (BAG) and and a BOG is that the BOG is physically shorter, and outputs less signal. I do not need a preamp with my BAG, but I do use one on my BOGs sometimes. A little zig-zag is OK, I've done that and it still works. Some folks will tell you that you do not need to terminate a BOG, but I have found that they perform better when you do.

      If raw noise is the problem, then try a good noise cancelling box, especially as you are running a vertical. The MFJ 1026 is useful on both local and skywave noise, but W8JI first re-engineered the 1026 then came up with his own design, and DX Engineering now sells it commercially. I'm told it's the bees knees for noise cancelling, but I have not tried it. The Timewave ANC-4 seems to work for local point source but not on skywave or area noise.

      Having a really good receiver with sharp filter skirts that don't ring when you dial the passband down to 100 hz or less helps immensely. That was probably the big difference between the K3 (and the KX3) a buddy of mine, now SK, had and my 590SG- the Elecraft rigs would not ring near as much as the Kenwood when the filters were tightened down in noisy conditions; I'd have to ease off the RF gain to stop the ringing. Apart from that, the receiver in the 590 SG is almost as good as the K3, and maybe just a bit better than the KX3.

      There are a number of low altitude loops described in the literature, EWEs and flags and Pennants, but they are all small. Part of the problem with small receive antennas is that you need a preamp for the low signal, and that can bring its own issues. The other part is the lack of directionality. "Low Band Dxing" has probably the best discussion of listening antenna evaluation criteria I know.

      Warm regards, SiG!

  8. Still planning on taking the test, but got delayed - sports. Will keep you posted.