Category Archives: Facebook Notes Series

First USA to Europe Amateur Radio 2200 Meter QSO

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

It was early morning on the 28th day of March, 2018. Most people were sound asleep but not me. I was in my ham shack, hands trembling, heart pounding as I typed a few letters and numbers into my logging program. I could barely breathe. I had just completed one of the most exciting QSOs of my nearly four decades chasing DX. This single QSO cost more money and time than any other I had ever made. It was a QSO with England. You may wonder what is so exciting about that when any ham with five watts and a piece of wire can contact England from Maine. Well, this was special because we did it on the 2200 meter band. It was the first amateur radio USA to Europe QSO on what is, for us, a new band. This was no easy feat. It required months of station building and four nights just to complete the QSO. Some would call it a ridiculous folly and see no sense at all in it. But to me this is the true spirit of amateur radio, finding a way to communicate against the odds, adapting equipment and technique to accomplish the desired result. It is man and his machine against nature, determined to succeed under the most difficult circumstances.

The 2200 meter band allocation is 135.7 to 137.8 kilohertz in the long wave part of the radio spectrum known as LF or low frequency. In some ways this goes back to amateur radio’s early roots on 1750 meters, but it had been more than 100 years since U.S. amateurs were allowed to transmit in this part of the radio spectrum. These frequencies are not easy! Normal size antennas would be huge. A half wave dipole would be 3400 feet long; a quarter wave vertical towering to a height of 1700 feet. Natural and man made noise tend to be very high in this part of the radio spectrum and ionospheric propagation is feeble compared to the short waves. On top of that, we are only permitted to run one watt effective isotropic radiated power (EIRP). That is flea power compared to what we can use on most any of our higher frequency allocations! By comparison, when I was doing EME (moonbounce) on the two meter band I was legally running about 450,000 watts EIRP. But ham radio DXers who like a good challenge can be a very determined lot. The greater the challenge, the greater the reward.

I became interested in 2200 meters in late 2016 after the local club asked me to prepare a report on this and the 630 meter band, which were expected to soon be opened for amateur radio use in the U.S. At that time the only way to legally transmit on either band was to get a Part 5 FCC license under the experimental radio service. One could almost write one’s own ticket on power limits and frequency allocations but this wasn’t amateur radio. I did apply for and was granted a Part 5 license but never used it since FCC opened these new bands to amateurs just as I was getting a station put together. I found receiving on 630 meters to be relatively easy, if somewhat plagued by noise and available antennas. But 2200 meters was a very different thing. It took weeks of experimentation and testing to detect the first trace of signal on this band. Many weeks later after more trial and error I was rewarded with my first reception of a ham radio signal from Europe on the band when DC0DX appeared in my WSPR decodes. I confess it was then that I first started to dream of someday making a two way QSO across the Atlantic on long wave.

I thought I had plenty of time to build a station, since the FCC process on opening these bands had been dragging on for years. But in the Spring of 2017 the announcement came that we would get these new bands in a few months! Now the race was on. I frantically began building transmitting apparatus. I didn’t quite make it for opening day in October but I was on the band a few weeks later. Early amplifiers were plagued by budget shortfalls and poor performance. By mid February, 2018 I had managed to achieve 0.5 watt EIRP, just three decibels below the legal limit. The flood gates opened and to my amazement I started receiving numerous WSPR decodes from European stations. Wow!

I believed a two way trans-Atlantic QSO was in my future but was not sure when. I was eager for an attempt but still very much struggling with equipment and budget. I was hearing stations from Europe. Stations from Europe were hearing me. But for the most part, those who heard me did not have transmitting capability or not sufficient to reach across the Atlantic. The best bet would seem to be 2E0ILY. We had conducted tests earlier in the season and I could often copy his JT9 beacon. Chris could occasionally copy my WSPR signal but not at sufficient strength for JT9 to be viable. I knew there were ways to get it done, but this would take several nights. I was hesitant to ask anyone to commit such effort and time to a QSO.

As the relatively quiet season was drawing to an end I realized another season is never guaranteed for any number of reasons. I had given the matter considerable thought. There were no practical digital modes which would work with the low signal levels involved. Two old school modes came to mind: QRSS and DFCW. Both are very slow, trading time for weak signal detection capability. QRSS is extremely slow CW, so slow in fact that it can only be copied by reading it off a computer screen. In this case, a speed of QRSS60 would be best, meaning that each dot would be 60 seconds in duration. A dash is three times as long, just as in normal CW. This mode requires nothing special for equipment, as it uses on/off keying of a carrier and is fairly tolerant of frequency drift. But, the shortest element, the dot, sets the achievable signal to noise ratio. There is no advantage gained from the dashes being three times as long, so it is essentially time wasted. Time is valuable, as signal fading means you have a limited amount of time to copy the message. DFCW, or dual frequency CW is an offshoot of QRSS in which dots and dashes are the same length but sent on slightly different frequencies so that one may be differentiated from the other. This saves considerable time with no reduction in signal to noise ratio but requires more complex transmitter keying and reasonably tight frequency stability. In a typical DFCW60 transmission, the dot to dash frequency shift is a small fraction of a hertz. Transmitter and receiver drift must be held to less than this in order to avoid dot-dash ambiguity at the receiving end. It would take about an hour to send two call signs at DFCW60 speed. It was now late March. Clearly there would not be enough common darkness between Maine and any part of Europe to allow a QSO to be completed in a single night at this speed.

It may be useful to consider what is a QSO. These days the term means different things to different people. I came up through the DXing ranks with what is now a somewhat old school definition for a minimum acceptable information exchange to claim a QSO under very weak signal conditions. I still firmly believe in the old way, as we are after all supposed to be communicators. That definition is that each station must receive from the other both call signs, signal report or other piece of information, and acknowledgment. This requires that two transmissions be copied in each direction. Anything less than that does not seem like communication to me, and leaves me with no sense of accomplishment.

It seemed the best way to go about it would be to borrow operating and reporting techniques from EME, modifying procedure slightly to account for the much longer period of time required to send a message on the long waves. In this procedure, the letter O would be used as a signal report to indicate full call signs had been copied; R and O would be used to indicate full call signs plus signal report had been copied; R by itself to indicate call signs, report, and R (as part of R and O) had been copied. As for timing, it seemed sensible to use night by night sequencing. That meant the two stations would take turns transmitting, one going the first night the other the second, alternating back and forth throughout the QSO. It would take a minimum of four nights to complete a QSO, assuming the full message could be copied each night. If it wasn’t, additional nights would be required for repeats. That’s really slow! But it did offer some advantages with the equipment available. In order to achieve the required frequency stability I would have to use my QRP Labs Ultimate 3S beacon transmitter. The U3S is a great piece of gear, but editing messages is tedious. Night by night sequencing would give me all day to change the message for the next night’s transmission! A complete QSO would look like this, where bold indicates my transmissions, italics indicate transmissions from the other station:

2E0ILY N1BUG
N1BUG 2E0ILY O
RO
R

Meaning of the first line is obvious. I am transmitting both call signs. In the second line my QSO partner adds the signal report, O, to let me know he had copied both call signs fully. In the third line I send RO which means I have copied call signs and my report, your report is O. In the last line my QSO partner sends R, meaning I have copied all on my end. When I copy the R the QSO is complete. If a message is not copied, or not enough information is copied, then one continues to transmit the previous message until getting something back which advances the QSO.

I had worked out a viable technique. Now I just needed a QSO partner. Just in time I worked up the courage to ask Chris, 2E0ILY if he would be willing to give it a try. I was very happy when he said he’d have a go at it.

We had decided I would transmit the first night, so I set the U3S to send ‘2E0ILY N1BUG’ over and over during the hours of common darkness between our respective locations. It turned out to be an ugly night in terms of weather. I was getting heavy wet snow squalls. Nothing causes a 2200 meter Marconi antenna (vertical) to go out of resonance any quicker than wet snow! These antennas are electrically short and require huge loading coils to resonate them. They are high impedance antennas and the bandwidth is very narrow. These antennas are prone to changing characteristics on a whim. Every time the snow started, stopped, changed intensity or the amount of snow clinging to the antenna changed, the thing went wandering up or down the band and required retuning for resonance on the operating frequency. Fortunately the variometer at the antenna base was motorized and I could adjust it from the comfort of my transmitter room. But I had to keep a constant vigil, watching antenna resonance and adjusting as needed. I had my finger on the switch for variometer adjustment far more than not. After a while my fingers were getting sore from constantly manipulating the tuning switch. Perhaps I shouldn’t have used a miniature toggle switch there. If you think this was an automated QSO without operator involvement, think again! My presence and diligence at the controls was absolutely vital that night!

Message copied from 2E0ILY on the second night of the QSO (annotated). Note dots on the lower frequency, dashes shifted 0.187 Hz higher. When the signal is this strong, elements tend to bleed together a little but since they are of fixed length it is still very readable.

The next night it was my turn to listen. Due to the extremely slow speed DFCW is copied visually using software designed for this purpose. Anxiously I stared at the screen. When I wasn’t nervously pacing, that is! I began to see traces of signal, then an odd letter here and there. There was a B, a 2, a Y and I even thought I saw an O but couldn’t be sure. Eventually conditions stabilized and I began to get steady print on the screen. Waiting 60 seconds for a dot or dash to fully paint on the screen can be agonizing. Slowly the elements accumulate and become characters. If you are lucky, propagation holds up long enough to copy the full message. Fortunately, after somewhat of a slow start copy remained solid and I eventually had N1BUG, 2E0ILY and a very nice O painted on my screen! I had copied full call signs and a signal report indicating Chris had got full call signs from me the previous night! We were half way there!

The third night I was transmitting again. Since I knew Chris had already copied full call signs from me, it was not necessary to transmit them at this stage of the QSO. Technically I could have just sent RO repeating throughout the night, but being of the cautious type I decided to include call sign suffixes to provide positive evidence the correct station was being copied. Thus the message I transmitted was ‘ILY BUG RO’. This was a risk as it takes far longer to send than simply ‘RO’ and signal fading can be a huge factor. At least the weather was better and I didn’t have to ride the variometer all night.

Soon it was night four, back to pacing and staring hopefully at the screen. I was especially nervous that night, as I had some strong, drifting interference right on top of Chris! Finally it moved just enough that I could make out ‘BUG ILY R’. There was rapid fading and the dash in the R was much fainter than the rest. Fainter but unmistakably there. I was positive about the R but being the cautious type and realizing this QSO would be an amateur radio first I really wanted to see it more clearly before declaring the QSO complete. The signal faded and nothing was seen for hours. Sunrise at 2E0ILY was fast approaching and I had to make a decision. Was I going to log the QSO or retransmit my RO message the following night in hope of getting better copy of the R on night six? Just before dawn the signal reappeared, very weak. I could barely make out ‘BUG IL’, then the ‘Y’ was quite strong. Given the proximity to sunrise every minute felt like an eternity. Ticking of the clock became offensively loud. It was going to take another four minutes to get an R! Would it hold up that long? Slowly, as the clock ticked and my heart raced, a crystal clear ‘R’ painted on the screen. There were traces of signal for some time after that but nothing I would call readable, save a stray ‘Y’ that somehow came through well past dawn. So it came to be that shortly after 0600 UTC (1:00 AM local time) on this, the 28th day of March, 2018 I entered this QSO into my station log. We had done it!

QSL card received for this very memorable QSO!

This was an amateur radio first from the U.S. but nothing new in terms of distance on the 2200 meter band. Canadian stations, operating under amateur call signs but otherwise a program similar to our Part 5 licenses, had worked Europe years earlier. Much longer distances had been covered. But for me this was one of the most exciting QSOs of my nearly 40 years as a DXer. It ranks right up there with my first EME QSO, the QSO that put me on the DXCC Honor Roll and several other notable events such as being credited with the first North American two meter auroral E QSO back in 1989. My thanks to Chris, 2E0ILY for his time and patience to make this happen – not to mention the kilowatt hours of electricity expended.

DFCW may be old school but it gets the job done under extremely difficult conditions. DFCW ‘decoding’ is done by the human operator. Deciding what has been copied is not left to computer software which may use assumption or non amateur radio means to fill in things it couldn’t positively make out over the air. DFCW is painfully slow but here we had a very positive over the air exchange of full call signs, reports and acknowledgement without any shortcuts or fudging. I was very pleased with that!

Although this single QSO cost more than any other, this was a low budget operation. Most of the LF station consists of low cost kits and home built gear. Equipment used at my station for this QSO was the QRP Labs Ultimate 3S driving a home built amplifier to 175 watts output. The transmitting antenna was a 90 foot Marconi (vertical) with a top hat consisting of three wires each 100 feet long, spaced five feet apart. Three one inch diameter aluminum spreaders plus triangular wire sections at each end are electrically part of the top loading. This is resonated at the base with an inductance of approximately 2.3 millihenries. Loss resistance at the time was near 100 ohms, resulting in EIRP of 0.5 watt. For receive I used a 30 foot low noise vertical, band pass filter, W1VD preamp, and a modified Softrock Lite II SDR receiver.

My First Night “High Power” WSPRing on 630 Meters

Leave a reply

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

I have been listening on 630 meters for over a year and I had operated a WSPR beacon two previous nights with very low power of about 15 milliwatts EIRP (Effective Isotropic Radiated Power). Even at that power level I was heard by more than 25 stations at distances to beyond 1000 miles, 1600 kilometers. But last night as winter descended upon the region with the first significant snowfall, I was transmitting with 22 watts TPO (Transmitter Power Output), resulting in about two watts EIRP. That is still four dB below our legal limit of five watts EIRP. Results were better than I expected for my first night, even though propagation was certainly not at its best!

At times I am a rabid contester, an avid DXer, an experienced builder of antennas and equipment. I love radio. I enjoy all of these activities but if I had to describe my pursuit of radio in one word it might be explorer. I love trying something new, venturing into little used territory, pushing limits, trying to beat the odds. I have a well equipped station. I could easily converse with amateur radio operators around the world most days just by turning on a radio and speaking into a microphone. Instead I am driven to pursue nearly impossible contacts on frequencies that do not easily go the distance. I especially enjoy pushing the limits of propagation, equipment and myself as an operator on modes where the human ear/brain is the decoder. Unfortunately that is becoming a rare thing in today’s world of digital modes where the computer does the decoding, all too often using only partial information received over the air, the rest filled in from a database or assumed because it was information previously known to the decoder. The continuing erosion of what represents a two-way amateur radio contact saddens me beyond words. Nevertheless I continue to find joy and excitement in the exploration of frontiers which, if not new to mankind, are new to me. I regret only that there will not be enough time to explore all there is to see and do in radio.

So it was that little more than a year ago I began my quest to conquer the two new low frequency bands, 630 meters (472 to 479 kHz) and 2200 meters (135.7 to 137.8 kHz). I spent the first winter learning about and building receiving equipment for those frequencies. There was a learning curve and I had to find what worked within my budget. Mission accomplished.

In the Spring I set my sights on building a transmitting station but quickly ran into a setback. The only way to put up a reasonably efficient antenna in the space I have would be to support it between my two existing towers. It didn’t take long to discover the older, weaker tower would not stand the strain of such an antenna! There was only one thing to do: replace the tower! The search for materials took all summer and the project wouldn’t have been possible at all without a great deal of help from friends. The work began in October and was not complete until the middle of November. That left little time before the onset of winter to build the antenna, a transmitter, and all the associated things that go with it. The antenna, a Marconi-T made of wire and strung between two towers, is shown in the cover photo.

One has to get into a very different mind set about antennas at these frequencies. Most of us are accustomed to “full size” antennas – dipoles, verticals, loops – which radiate nearly all the power we put into them. In many cases we use directional “gain” antennas that actually make our effective power more than we have coming out of the transmitter – in a favored direction. Very few if any will be able to reach anything approaching 100 per cent efficiency at 630 meters and no one will at 2200 meters. Forget about gain antennas! Horizontal polarization does not work well at these frequencies. A quarter wavelength vertical for 630 meters would be 490 feet (149 meters) tall and for 2200 meters, 1700 feet (520 meters)! Not only that, but unless located over salt water a vertical needs an extensive system of ground radials around it to be efficient. Most amateur antennas at 630 meters will radiate no more than a few per cent of the power fed to them, while many will be less efficient. At 2200 meters reaching one per cent efficiency will be very difficult for most, impossible for many. My 90 foot (27 meter) tall vertical with three 100 foot (30 meter) horizontal top loading wires sits over a radial system with more than 10,000 feet (3048 meters) of wire in it. Yet the best I can hope for is 3% efficiency on 630 meters and 0.25% efficiency at 2200 meters. The vast majority of power is eaten up by ground losses and losses in the large loading coils needed.

In fact, once we cancel out capacitive reactance due to the antenna being electrically short, the resistance we see isn’t really the antenna at all – it is dominated by loss resistance! Even at 630 meters the radiation resistance of a typical antenna will be an ohm or two, in many cases less. Even very good ground systems will be many ohms. My radiation resistance on 630 meters is 1.25 ohms. I measure 39 ohms when the antenna is resonant. Almost all of that is the ground system loss resistance, and that is where most of my power goes! This really is a different world from the higher frequencies.

The challenge doesn’t end there. After we manage to get a few watts radiated, we have to contend with the fact the ionosphere doesn’t propagate signals at low frequencies as well as it does higher ones, while both atmospheric and man made noise is much worse down here! It’s a wonder we manage to communicate at all. But we do. That’s the challenge, and that is what attracted me to this.

The variometer (left) is an adjustable inductor used to cancel out capacitive reactance in the antenna and resonate it on the desired freqeuncy. The matching transformer on the right steps up the resistance of the antenna system (in this case about 39 ohms) to the 50 ohm impedance of the feed line and transmitter.

By midday December 9 I was ready. The antenna was up, the variometer adjusted, matching transformer properly configured and my little 25 watt home made transmitter was ready to strut its stuff. I set it to transmit as a WSPR (Weak Signal Propagation Reporter) beacon, sending out a two minute standard WSPR message every ten minutes. In broad daylight, I received several reception reports after my very first transmission! WSPR reception reports are available on the Internet almost immediately and may be viewed as a list or displayed on a map.

The transmitter, consisting of a QRP Labs Ultimate 3S exciter (assembled from a kit) on the left and home made amplifier on the right.

I spent the first few hours nervously checking the transistor in the amplifier with my finger to see if it was running too hot, watching squiggly green lines on the oscilloscope for any sign the antenna was drifting off frequency or something breaking down outside. To my joy all continued to look good! It was not as if I had no reason to wonder. One transistor had died weeks earlier during initial testing of the transmitter. That occurred while running into a perfect resistive load, not an antenna that might be imperfect or change on a whim. These low frequency antennas which are, of necessity, electrically short actually can change on a whim! The capacitance and hence resonant frequency can change as they sway in the wind. The resistance can change with weather and season. With several inches of snow forecast for the night, I didn’t know what to expect. So I nervously watched over the system. After every transmission I checked to see where I had been heard.

As sunset approached and passed, the band naturally stretched out. I began to get stronger signal reports and was being heard at ever greater distances. After some time there was a report from a station in the Netherlands! My puny signal had made it all the way across the Atlantic on a frequency below the AM broadcast band! This was soon joined by reports from the Cayman Islands and Canary Islands. Africa! Toward morning I even got a reception report from Hawaii! Just before dawn I observed some variations in the antenna system. The two sine wave patters on the oscilloscope display began shifting slowly, almost rhythmically back and forth with respect to one another. This was caused by changes in antenna capacitance as it swayed slightly in a gentle breeze. I have heard the effect described “as if the antenna is a living, breathing entity” and I would have to concur with that description. It was fascinating to watch. I got very little sleep and didn’t even notice it was one of the longer nights of the year. I was having too much fun! I was exploring!

Oscilloscope patters from the “scopematch” monitor the antenna resonance and resistance. If the antenna were perfectly resonated on the transmitting freqeuncy and perfectly matched to 50 ohms these two sine wave traces would converge into one. Here, one is shifted to the left slightly, indicating an off resonance condition (in this case exhibiting inductive reactance), and they are not of the same amplitude (height), a sign of imperfect resistance match (here showing the resistance to be slighty high).

There are many challenges and new experiences yet to come on the low frequency frontier. One of my winter projects will be to build a transverter so that I can transmit modes suitable for two way contacts. But the bigger challenge is getting operational on the lower frequency band, 2200 meters. The coil and variometer will be much larger, creating not only issues in construction but in protection from weather. The antenna impedance will be far greater, resulting in very much higher RF voltage and the possibility of interesting but unwelcome events such as insulation breakdown, arcs and corona! Undoubtedly the antenna will “breathe” to a much greater extent. On 2200 meters I expect a lot of action on the scope when there is any breeze.

0 Comments

⁠

Perseids 2017 on 144 MHz

Leave a reply

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

Woo-hoo! What a fun event! This was the first time in some years I had a good station for two meter DXing such as meteor scatter. I wanted to have some fun and see what I could work with it. This is undoubtedly the best setup I ever used for meteor scatter, due mostly to the antenna height. I am running 1500 watts to a 13 element YU7EF yagi at 110 feet (33 meters). However several factors re not ideal. The feedline is good cable but long with about 2.5 dB loss. I don’t have a mast mounted preamplifier so my receive may not be optimum. My location is not the best. I am in a small valley next to a river. Given antenna height, my horizon in the most important direction, southwest, ranges from about +0.0 to +0.5 degree.

I was able to complete some QSOs more than 1200 miles (1930km) on random in response to my CQ. My best distance this shower was also my all time best personal meteor scatter DX record with KC4PX at 1334 miles (2146km). Ivars heard a lot more from me than I did from him but there was a 6dB power difference. He was running 350 watts to a single yagi antenna. His best signal here was +6, which is some 10 dB above the minimum that I can decode. This not only gives me a new personal MS DX record, but also hope for longer distances in the future. It took 47 minutes to complete the QSO but it was time well spent! Ivars also heard me at several other times during this meteor shower. My horizon is +0.3 degree at the exact heading to KC4PX.

N1BUG 144 MHz MS QSOs for Perseids 2017

The meteors were best between approximately 0300 UTC August 12 to 1700 UTC August 12. During peak times some random QSOs could be completed in the minimum number of 15 second sequences, including W0VB at a distance of 1162 miles (1870km). This was not one long burn, but a collection of smaller meteors that allowed us to transfer needed QSO information in every 15 second slot.

I cannot say for sure that it was one long burn but I had three consecutive full 15 second periods of N4QWZ with two of my transmit periods in between. If this was one long burn as it appeared to be from signal quality and characteristics, it was more than 75 seconds!

I made 22 meter scatter QSOs in 13 states. It seemed odd that I didn’t work any Canadian stations. I did not count grid squares.

I can hardly wait for the next major meteor shower! You can be certain I will be pushing for longer distances in the future. I should be able to extend the distance with a full legal power station at the other end.

Using Meteor Scatter Propagation on VHF

Leave a reply

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

Note: I may add illustrations later, but want to get this out before the peak of the 2017 Perseids meteor shower.

You’re staring into the night sky when all of a sudden a streak of light appears. It’s caused by a meteor burning up as it enters the Earth’s atmosphere at high speed. It may be no bigger than a grain of sand but it makes quite a show. There may very well be a ham radio operator somewhere trying to bounce a signal off that meteor trail.

Since the 1950s, VHF ham radio operators have been using ionized meteor trails to reflect their signals beyond normal everyday range. While the tools and methods used have changed over the years, meteor scatter remains a popular method of communication. I mentioned this propagation mode only briefly in previous VHF weak signal operating primers, so let’s take a closer look at it.

What is meteor scatter good for? It’s not a ragchew mode. At 50 MHz the ionized trail may only be capable of reflecting the signal for a fraction of second, or it could be up to a couple of minutes in extreme cases. The higher you go in frequency, the fewer meteors capable of supporting propagation and the shorter the signal duration. At 144 MHz anything over 30 seconds is relatively uncommon but some may last a minute or so. There are still fewer meteors capable of supporting propagation at 222 MHz. Only the biggest and fastest provide very brief propagation at 432 MHz. Most of the time, several meteors will be needed to complete a “minimum QSO”. So just what use is meteor scatter? Using special techniques, it is possible to work stations over distances up to 1400 miles. Meteor scatter is a good way to get more states, grid squares, or just make some nice longer distance contacts on VHF. It can be fun and exciting!

Let’s define what we mean by “minimal QSO”. Long ago it was decided that a valid contact needed to demonstrate some basic level of capability to exchange information (communicate) over the air between two stations. The agreed upon standard was that for a QSO to be valid the following information had to be exchanged in both directions: call signs, signal report (or other piece of information such as a grid square) and acknowledgement that the report was received. This means that if I am trying to make a QSO with W1XYZ, I must hear his call sign and my own. I must hear a signal report and I must hear some confirmation (usually “roger” or RRR) that he got the signal report I sent him. W1XYZ must receive the same information from me.

In meteor scatter you don’t hear the other station all the time. Far from it! Signals come and go erratically in short bursts. In order to make maximum use of available meteors and prevent both stations inadvertently transmitting at the same time, a special operating procedure has evolved. Stations take turns transmitting. In North America the transmit and receive periods are usually 15 seconds each. This requires accurate clocks. During a scheduled QSO attempt, both stations initially start out sending call sings over and over during their assigned 15 second periods. When one station copies call signs, that station will start sending a signal report with call signs. Assuming the other eventually copies both call signs and a signal report he will send acknowledgement that he got his report (usually just R) and a report. When all of that is copied at the other station he sends RRR. The QSO is technically complete when this RRR is copied but since the station sending it has no way of knowing it has been heard, typical procedure is for the one who receives RRR to send 73. Reception of 73 lets the other know all is complete. If you end up sending RRR and never receive a 73, you won’t know if the QSO is complete unless you check with your QSO partner by some other means such as email or an internet chat site. If he got the RRR it is a valid QSO. The honor system is very much in play here. This sounds far more complicated than it actually is. You get used to the process after a few QSOs. The process for a non-scheduled contact (where one station was calling CQ) is similar. Theoretically, using 15 second transmit/receive periods, a QSO can be completed in just over a minute. On 50 MHz it sometimes works that way. On higher frequencies it usually takes longer and sometimes even after 20 or 30 minutes there haven’t been enough meteors to complete the QSO exchange.

In years past, using SSB or CW the procedure followed that form exactly. Once a QSO progressed beyond a need to hear call signs, they were omitted from the transmissions. Most of the time this worked OK. One could often tell from the voice or speed and “fist” that the correct station was being copied. With digital modes, call signs or an abbreviated form of them is usually sent at each stage of the QSO along with whatever info is required at that point. This helps to make sure you are copying the intended station and not someone else.

You may be thinking this sounds like a lot of work just to exchange enough information to log a contact. Maybe you wonder what is the point. To the person who just likes to talk this method of communication makes no sense. But for those who enjoy a challenge, are chasing states or grid squares on VHF or just looking to do something few hams even realize is possible, meteor scatter can be very interesting and rewarding! There is a thrill in that signal suddenly appearing out of nowhere. Completion of any given QSO attempt is by no means guaranteed. Some attempts succeed, some fail due to insufficient number of meteors capable of supporting propagation or other factors. Every completed QSO feels like an accomplishment — because it is!

Meteor scatter has both predictable and unpredictable qualities. Sporadic meteors (those not associated with any particular meteor shower) are best in the morning hours around dawn and shortly after. Relative velocity is also usually higher in the morning unless the meteor is on a path almost parallel to that of the Earth. There are enough of these sporadic meteors to permit QSOs on 50 MHz every day of the year. Winter can be tough going on 144 MHz but most of the year every morning works to some extent. Several major meteor showers each year provide greatly enhanced opportunities on those bands along with the possibility of 222 and 432 MHz. Most notable are the Perseids in August, Leonids in November, Geminds in December and (though of very short duration) Quadrantids in January. There are several other meteor showers that don’t compare to those but nevertheless elevate meteor counts well above the sporadic rate. Regardless of season, time of day, or the presence of a meteor shower, exact meteor rates, burst duration and timing can never be known. You may get 30 bursts in a 10 minute period and not a single burst in the following 10 minutes. You never know. This unpredictability adds to the fun and challenge. During meteor showers there are optimal times of day for specific directions. This has to do with geometry of the intended communication path and the meteor trail angles which change as the Earth rotates. This was much better known and utilized years ago than it is now. Most operators today just take their chances at whatever time they feel like operating.

What kind of station do you need to work meteor scatter? On 50 MHz, 10 watts to a three element yagi will get you started. 100 watts will do quite well. I have made meteor scatter contacts to more than 1000 miles on 144 MHz with 25 watts and a six foot long yagi, but it is not easy! 100 watts to a 12 foot yagi is a good minimum setup to aim for on two meters. If you are looking to break into the extreme distances, 1300 to 1400 miles, you will need more power and a larger antenna. At 222 MHz, 150 watts to a good long yagi (say something on the order of a 20 foot boom more more) is advisable as a minimum, and at 432 MHz you’ll probably need several hundred watts and a monster yagi or array of several yagis.

WSJT-X software running MSK144 mode is the default for meteor scatter work at the present time, but modes tend to change in the modern era. MSK144 transmits data at such a high rate of speed that call signs plus grid square or call signs plus signal report can be received in a burst as short at 72 milliseconds! This allows QSOs to be completed using much smaller meteors (hence a greater number of them) than SSB or CW did in the past. Almost always this is just what you want but on rare occasions there can be a down side to new methods. You can’t shorten the 15 second transmit/receive periods “on the fly”. It won’t work. So if you get a long meteor burst, say lasting a full 15 seconds, you may only get one piece of QSO information through on it; possibly two if it overlaps the station transmit periods sufficiently.

I am going to digress for a moment to add a couple of historical notes. These may illustrate some of the rare magic that meteor scatter operators never forget.

On SSB (and CW to a lesser extent), an alert operator could “pounce” with a very short transmission if he was hearing the other station right at the end of a 15 second period. This sometimes allowed for a quick back and forth with the whole QSO being completed on one meteor trail. One was always on high alert, ready to pounce! Back in the 1980s I was running a SSB meteor sked with a station in Missouri, about 1250 miles away. We suddenly got a long burn and abandoned the 15 second sequencing to rapidly complete the exchange. I was immediately called by another Missouri station who had been listening in. I worked him and then a third, all on one meteor!

Making meteor scatter QSOs at 1400 miles is usually quite difficult, but it can be done. One time I was running a 144 MHz meteor scatter schedule with a station in Greenland, a distance of just over 1400 miles. This would have been a new country for me on two meters and a new personal distance record. At the time, very high speed CW meteor scatter was the normal method in Europe, while SSB was the standard in North America. European high speed CW was so fast it had to be recorded and then played back at slower speed for copy, even among the very best CW operators. One minute transmit and receive periods were used. The Greenland operator (visiting from Denmark) was set up for high speed CW. SSB was the standard in North America at the time, so I had no means to record and play back CW at lower speed. The Greenland operator agreed to transmit at 40 wpm which I could copy by ear. I was using a memory keyer to send at 100 wpm, slow by the European standard but was the best I could do. As it happened we got almost no short bursts at all and the QSO was not progressing. Suddenly he popped out of the noise and I heard him for a full 45 seconds! That is very uncommon at this extreme meteor scatter distance, and was all the more unusual since I have a small hill in that direction blocking extreme low angle signals. There was nothing I could do. Because of the automation and method, we were stuck with the one minute transmission periods. Had we been doing SSB or even conventional speed CW using shorter periods, with operators doing all the decision making in real time, this would undoubtedly have been a complete QSO. We might have squeezed everything in using MSK144 with 15 second transmit/receive periods. Nothing more was heard during our schedule, so I did not get my new country or personal distance record. However this was an exceptional event and exciting even without a QSO in the log to show for it. In all my years working meteor scatter I have never heard another long burst like that at 1400 miles. I did work Greenland on EME (moonbounce) years later.

Getting back to the present, let me introduce a few more relevant points.

Antennas are generally pointed toward the station you want to work, but the optimum path can be skewed a few degrees to one side or the other. The WSJT-X software calculates suggested headings. It also helps keep you on track during the QSO process because it knows what you should send next based on what you have received. There are pros and cons to digital modes, but at least I don’t lose my voice for three days after the Perseids and Geminids meteor showers!

Meteor scatter can be used at any distance less than the 1400 mile theoretical limit, but under about 600 miles it becomes considerably more difficult with fewer and shorter bursts. This is even more apparent if you have a high antenna or one that has a narrow vertical lobe such as stacked yagis. Being able to elevate the antenna a few degrees above the horizon can help with the shorter distances. 700 to 1100 miles is the easiest range although this may vary somewhat for different antenna patterns, height, etc.

Various online chat pages and scheduling tools are an aid in finding stations to run schedules with. ON4KST chat and Ping Jockey are the most widely used. If you just want to make random contacts (calling CQ or responding to CQs), there are MSK144 calling frequencies for that. In North America, these are 50.260 on six meters, 144.150 on two meters. There is activity on 50.260 almost every morning. It seems random activity on 144.150 has decreased significantly in recent years but some CQs can occasionally be found. QSOs can be completed on the calling frequencies when things aren’t too busy. During periods of high activity there is a procedure for calling CQ on the calling frequency, announcing where you are listening for calls. When you hear someone calling on your listening frequency, you move your transmitter there to complete the QSO. Helpful advice on operating procedures can be found in the WSJT-X User Guide and other references, but if possible you may want to find a local elmer who knows the ropes to help you get going. MSK144 works well with strong stable signals too, so you can test with a local station.

If you have six or two meter capability and are looking for a new challenge or just a change of pace, give meteor scatter a try! It’s not your average ham radio communication but it can be quite rewarding. If you don’t already have it, download the WSJT-X software, version 1.7.0 or later. You will need a computer with a sound card and some type of radio interface. Then listen on 50.260 in the mornings to get a feel for what meteor scatter is all about. Here in the northeast U.S. at least, most activity tends to be between the hours of 6 and 9 AM outside of major meteor showers, and possibly any time of day or night during showers.

Two Meter Sporadic E Propagation

Leave a reply

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

To the DX minded VHF weak signal operator, every contact beyond everyday range is exciting. This is a different world from the HF bands where long distance contacts can be made at almost any time. On two meter SSB or CW, contacts to 200 miles with a modest station and up to 500 miles running high power and a good long yagi antenna are about the every day limit. Beyond this, we need special propagation, which can take several forms: tropo, aurora, meteor scatter, sporadic E. Tropo can theoretically be any distance but only in very rare or special situations can one make contacts beyond 1000 miles or so. The ionospheric modes (aurora, meteor scatter, and sporadic E) have a rule of thumb theoretical maxium distance of 1400 miles based on path geometry with average height of the ionospheric E layer where the reflections take place. Rarely will you work anything beyond that distance, and when you do, sporadic E will probably be responsible. The fact that DX opportunities are less common at VHF is one of the things that attracts some people to it. There is a certain thrill and satisfaction in doing the unusual, the rare, beating the odds.

Many two meter DXers say sporadic E (also known as Es and E skip) is the most exciting propagation mode of all on the two meter band. It sure does get one’s blood pumping! For one thing, this propagation is quite rare at 144 MHz. Just catching one of these openings is an accomplishment. There may be years with a half dozen openings during the late May to early August season, but there can also be years with none at all. When it does occur, sporadic E propagation comes on suddenly, often producing very strong signals. Even with QRP it is sometimes possible to make 1200 mile contacts with ease. I once worked a station in South Carolina who was using a two watt portable transceiver with its built in whip antenna. He was booming into Maine! Openings can last from a couple of minutes to a couple of hours. The casual VHFer is likely to miss most of the openings that do occur. Those who monitor internet propagation reporting sites and/or have their own MUF monitor are are more likely to catch these rare openings.

I usually monitor conditions closely during the season but on the afternoon of June 13, 2017 I had been distracted. I walked into the shack in the late afternoon to find this in one of my browser tabs:

“VHF Propagation Map” uses APRS signals to map two meter openings. This is a classic sporadic E footprint. This site can be found at http://aprs.mountainlake.k12.mn.us/

Wow! I was probably missing a sporadic E opening! Hastily turning on the equipment I heard KE4TWI in Tennessee calling CQ. He wasn’t particularly strong and did not hear my low power call while waiting for the amplifier to warm up. Hearing no other signals I thought I had missed the opening. In fact I did miss an opportunity to work Tennessee and quite possibly further west to Missouri or other states. I began alternating between calling CQ on or near the North American SSB/CW calling frequency, 144.200, and tuning around looking for signals. I was about to give up when one of my CQs was answered by KD4ESV in Florida! This was a very good one, as the distance is 1436 miles. The opening would last for about an hour, but with relatively few operators aware of it I worked only four stations: KD4ESV (1436 miles), WA4GPM (1251 niles), N4TUT (1334 miles), and N4TWX (1283 miles). Nevertheless this was extremely exciting stuff! I was on two meters for more than 20 years the first time around. In all those years I worked beyond 1400 miles just once – to the Florida Keys on extremely rare double hop sporadic E, a distance of slightly over 1600 miles). This was only my second QSO past the “1400 mile wall” without using the moon as a reflector. Coming shortly after my return from a 10 year break it was especially thrilling.

This map shows some QSOs which were reported via the DX clusters. My 1436 mile contact with KD4ESV is shown. We can see contacts from southern New Hampshire to Tennessee and Missouri duing the part of the opening I missed. This map came from https://www.dxmaps.com/

The above map is one of several useful online resources for spotting openings, but it only shows contacts after they have occurred and been reported. Hence there is a lag, and since these openings can be short, in and of itself this is not the best way to spot openings. DX Maps also offers a real time Es MUF map, which may be more useful with a few caveats. The MUF map takes reported contacts on lower frequencies, such as six meters, then computes MUF based on distances and path centers. Suddenly rising MUF over 100 MHz can be an indicator of possible upcoming two meter openings. This is not foolproof. Some operators don’t report (or incorrectly report) the type of propagation when sending DX cluster spots. This can introduce erroneous data to the system, causing unrealistic MUFs to be reported. It can also miss some openings if not enough people are reporting QSOs from lower bands. Nevertheless it is very useful, especially since it can often give an early warning as the MUF starts to shoot up.

The Es MUF map was captured *after* the two meter opening, as the MUF was falling. The “hot spot” showing 111 MHz MUF had been over 160 MHz several minutes earlier, during the time I was working Florida from Maine. Note that this hot spot is at approximate path mid point for those QSOs. This is from https://www.dxmaps.com/

Another very useful tool for spotting potential two meter Es openings is to set up your own MUF monitor in the FM broadcast band. Years ago I had a receiver which I left tuned to a frequency around 90 MHz during the Es season. When I started hearing distant signals exhibiting the strength and fading characteristics common to Es, I would move it to around 107 MHz and keep tuning around that high end of the band. Whenever I heard Es signals there, I would start calling CQ on two meters. The system served quite well for catching these rare openings. These days a wide slice of the FM broadcast band could be visually monitored with a SDR. I would highly recommend this to anyone wanting to work these rare openings on two meters.

I have uploaded audio recordings from this opening to audioBoom:
https://audioboom.com/posts/6024876-2m-kd4esv-on-es-1436-miles
https://audioboom.com/posts/6024893-2m-wa4gpm-on-es-1251-miles
https://audioboom.com/posts/6024897-2m-wa4gpm-and-n4tut-1334-miles-on-es
https://audioboom.com/posts/6024899-2m-n4twx-on-es-1283-miles

Two meter contacts made by N1BUG on the evening of June 13, 2017

Fool Resistant Automated Band Switching: A Simple Design Project Using “Old School” Techniques

Leave a reply

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

The first week of Technician license classes I tell students amateur radio can be a lifelong journey of learning. For some it is a means to an end, be it providing public service or for personal safety while enjoying other recreational activities. For others it is a hobby but not necessarily something that leads to continuous learning or exploration. Then there are those like me. Maybe I have the heart of an explorer. I am quick to dive into exploring a new band or mode, especially if it is challenging. I appreciate and enjoy learning how to do things.

I am by no means an electronics expert. I am in awe of those who understand microprocessor and logic circuits and those who handle RF and microwave design with ease. I wish I understood and felt confident with those things but I have come a long way from the kid whose first project, a key click filter with two inductors and two capacitors, went up in smoke. Today I am able to solve some design problems on my own and occasionally turn junk into something truly useful. As long as my brain will continue to absorb new ideas I will continue to learn about radio and electronics. Sometimes the things I design use older technology because I understand it. Sometimes it is because that is the least costly way to do it. Sometimes both, as is the case with my current project.

I don’t learn well from books or any form of text. I learn better in a classroom, from videos, or best of all from hands on experience. There has been a lot of magic smoke released from electronics here over the years and I have learned much from doing things the wrong way! Many people have contributed to my ongoing education through the years, but Steve K0XP (formerly KO0U) stands out as the greatest mentor I ever had. Through daily email contact in the late 1990s and into the early 2000s, he tutored me on a wide range of subjects involving solid state analog and basic RF design. Steve explained one thing at a time, patiently repeating and rewording until it was absorbed. I have been thinking about that a lot on my recent design project, as it involves a basic concept I finally “got” through Steve’s efforts: using transistors as switches. The drawers full of transistors from which I pulled stock for this were part of an incredible gift Steve found for me.

I call my latest project FRABS (Fool Resistant Automated Band Switching). Everything here needs to be fool resistant. Otherwise the magic smoke gets let out of stuff. This project would be too simplistic for some, too advanced for others. It is within my comfort zone. I admit the design concept using transistor switches is yesterday’s technology. Some would use opto-isolators, some a microprocessor based design. I use transistors because I understand them, I have drawers full of them and they get the job done.

FRABS is almost harder to explain than to build. Last year I started getting back into VHF and UHF using transverters. I have only one station transceiver, which now has to serve for HF and VHF/UHF. I have more than one amplifier sharing a common high voltage supply, and my antenna switching system is somewhat complex, involving both transmit and receive antennas for HF. If I were to forget to put one amplifier on standby before trying to use another, bad things would happen. I once forgot to disable the HF amplifier and dumped 1500 watts of RF into a hybrid transverter drive attenuator rated 250 watts. Zap! So much for that device. Clearly simple wasn’t going to do it here. Simple can be good, as in keep it simple, stupid. But simple isn’t always fool resistant.

What I needed was some means of automating the various tasks involved with switching bands: route RF to the proper places, enable one amplifier while ensuring that all others are disabled, etc. I needed the added protection of having it only available through the automated system, with no manual method that the fool might use instead to blow stuff up. After some discussion with Dave, AA6YQ, developer of the extraordinary DXLab suite of software I have running in the shack 24/7, transverter support in Commander (DXLab’s transceiver control component) was extended to include all bands I planned on adding. Since Commander understands transverters, can control the radio through its CAT command set, and can control external devices through a parallel port I had the method of control. All I needed was to add a parallel port to my PC and to come up with an interface to take signals from that port and control the station switching.

The project started with a concept drawing. I have no time or patience for computer drafting, so I grabbed a piece of paper and started scribbling. This, with its somewhat cryptic notations, is what resulted. It gave me a clear overview of what I was trying to accomplish.

Fortunately I had a vacant PCIe slot in the PC. After some research, reading reviews, etc. I settled on a Rosewill RC-302E parallel port adapter. USB parallel adapters do not work in this application! They are printer drivers and do not provide low level access for “bit twiddling” that is necessary for this application. I was concerned about how much current could safely be drawn from the Rosewill since not all these adapters are created equal and none are designed to source current. I was going to need a couple of milliamps to control my interface. Testing revealed that this one can provide more than three milliamps with virtually no voltage drop. Very good! It took about 10 minutes to set up custom band switch buttons in Commander.

I didn’t need to use any sort of decoder or digital to analog device. The parallel port has 8 data bits which can be controlled by Commander. I needed only seven “states” for this project: HF, 50, 144, 222, 432, 903, 1296. That meant that I could use a single data bit for each state by having Commander write the appropriate value to the port to make a single bit (pin) go high. I used the following seven values: 1, 2, 4, 8, 16, 32, 64. A value of 1 causes pin 2 of the DB25 port to go high, or about 3 volts, while all others remain low, zero volts. A value of 2 causes pin 3 to high, 4 causes pin 4 to go high, and so on. Nothing could be simpler than that. I have the most significant bit, pin 9 (128) left over for some possible future use. I may end up using it in some way for our new 2200 and 630 meter bands.

I had already decided this was going to be a low budget project, making use of parts I already had. I was going to need both NPN and PNP transistors for the switching circuits. I had drawers full of PN2222, PN3904 (NPN), PN2907 and PN3906 (PNP) transistors. A quick look at the relevant data sheets indicated the PN2222 and PN2907 would be the better choice for this project. I got down to business working out the details of the hardware interface.

For HF (160-10 meters) and 6 meters, there wasn’t much to be done. Those bands are native to my station transceiver, the transverter select relays would all be de-energized for these bands, and I didn’t need sequencers. All that would be needed is a simple switch to enable the proper amplifier.

HF and 6 meters were easy, since those bands are native to my transceiver and very little switching would be needed. The higher bands (144, 222, 432, 903, and 1296 MHz) would require a bit more. There I would have to route RF to the proper transverter, one path for transmit, another for receive. I would also need to use a sequencer for these bands since fast (vacuum) relays become problematic or completely impractical and there would eventually be complications such as tower mounted receive preamplifiers. This means things need to be switched in a specific order with time delays when going from receive to transmit and vice versa. T/R sequencers are the usual way of doing that, and since a kit is readily available for $20 I wasn’t going to design my own. After evaluating what would be involved with using a single T/R sequencer on multiple bands, I opted to use one for each band. The switching would be simplified and I could adjust the step time delays independently for each band if I needed to.

The 2 meter (144 MHz) switching circuit. This same circuit is dupliated four more times for 222, 432, 903, and 1296 MHz. It’s a good thing I had those drawers full of transistors!

I was also going to need a drive attenuator for the transverters. They require a few milliwatts of 28 MHz drive. Putting the full 100 watts from the transceiver into them would surely let out some of the magic smoke! I was fretting about not having a needed resistor when some tutoring obtained through one of the VHF discussion forums reminded me of something Steve had taught me years earlier: the capacitive voltage divider. Straight out of the junk box an adjustable drive attenuator was built. The final implementation involves having the band select buttons in Commander set the transceiver power output to 10 watts and using 30 dB attenuation to drop that to 10 milliwatts. Perfect.

Circuit for the drive attenuator. C1 allows this to be adjustable from 27 to more than 50 dB attenuation. I’ve set it for 30 dB in my application.

FRABS isn’t completely finished at this point. It is up and running to the point of proof of concept. I have been using it to toggle between HF and 2 meters for the past few days and it is doing what I designed it to do. There were a couple of glitches on this mission. The smoke came out of an ancient transformer I used in the FRABS power supply, but digging a little deeper my junk box provided a more modern unit that turns out to be better suited anyway. I also had a brain fart and forgot to include base current limiting resistors for the PNP transistors in the first draft design. Poof! Oops! I just wasn’t thinking. I know they are required, and I knew instantly what I had forgotten when the first test failed. What is not shown on the schematics is a liberal sprinkling of bypass capacitors to keep any stray RF out of semiconductor junctions where it could cause all sorts of mayhem.

Inside the transverter drive attenuator. I liberated the type N and BNC jack and cable assemblies from an old Motorola MICOR UHF antenna network.

Thge assembled transverter drive attenuator. The heat sink was also liberated from an old Motorola MICOR UHF antenna network.

Inside the partially complete FRABS control interface during testing. There is one more large board to be added (it wil stack on top of the one at the upper right) and four more of the small green baords (T/R sequencers), not to mention a lot more wires.

Bottom view of the FRABS control interface during early testing. Eventually there will be cables plugged into most of those connectors.

The relays used to toggle the station from HF/6m to the higher bands are shown here mounted on a rack panel. It’s a bit messy in here. Cables going here, there, everywhere.

The transverter drive attenuator (left) and transverter select relays (right) mounted on the inside of a a multi-function rack panel. The wiring across the top of this panel is part of 12V DC power distribution to network components (unrelated to FRABS). Cables will be color coded by band. Here, white heat shrink tubing is used on cables for 144 MHz.

The 2 meter gear (minus that unrelated thing at the lower left) currently sits atop the rack mounted station PC.

This project is neither pretty nor elegant, but it does make station operation much simpler and more enjoyable. It also helps pave the way for adding bands with a minimum of fuss.

Exploring 630 and 2200 Meters: Part One

Leave a reply

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

Back in September I was asked by an officer of the local amateur radio club to say a few words about our (hopefully) upcoming new bands: 630 meters (472-479 kHz) and 2200 meters (135.7-137.8 kHz). I didn’t have much to say. I hadn’t thought much about these bands. It might have ended there but for my interest in early radio equipment. Several weeks later in one of the antique transmitter building forums I saw a post about “630 Meter Crossband Night” which is an event held each November. During this event, several Canadian amateurs call CQ on 630 meters and listen for U.S. hams to call them on 160, 80 or 40 meters. These bands are already allocated to amateurs in Canada and many other countries. In the U.S. there are a number of stations operating with FCC Part 5 Experimental licenses. There is more than the usual CW activity among these stations on Crossband Night compared to other times. I figured I might as well give it a go and see if I could hear anything at all. As is often the case with me, A plus B equals hang on, we’re about to take a U-turn and go off on another wild adventure!

My station transceiver, a Yaesu FT-2000, has a general coverage receiver which tunes down to 30 kHz so I figured I would be all set there. I didn’t know if any of my existing antennas would work at this frequency. I have several Beverage antennas ranging in length from just over 500 feet to just under 700 feet. They work well on 160 meters but at 630 meters they are on the order of a quarter wavelength long. That is too short to work as a Beverage. At best I figured they might perform as random short pieces of wire oddly coupled to coax and the ground!

It didn’t take long to find my first signal on 630 meters: VO1NA in Newfoundland, Canada. Joe’s CW signal was excellent, several S units above the noise. I called on his 80 meter listening frequency and had a crossband QSO with him. Later I had a similar QSO with VE3OT in Ontario, a distance of over 600 miles. Clearly I could in fact hear something on this mysterious medium frequency band! I heard a number o the FCC Part 5 stations as well, including WG2XIQ in Texas. Unfortunately they are not allowed to communicate with stations operating in the Amateur Radio Service so crossband or any other form of two-way contact is not possible.

As for antennas, I discovered that I could hear several stations on my 80 meter inverted V and even one or two on my 20-10 meter beam. The Beverages were a clear winner though. Oddly I would discover that night and more so in the nights which followed that my west-facing Beverage had the lowest noise level of the eight directions available and was the best receive antenna for 630 meter signals from all directions. As for just what causes this, I don’t know. They are after all acting as short random length wires oddly coupled to coax and ground. There is no telling what the pattern is or how they might be interacting with each other or with other structures.

As a frequent user of the ON4KST internet chat site for low bands (160-40 meters), 6 meters and VHF/UHF (2 meters and up), I was aware Alain also had a chat page for the low and medium frequency bands. Naturally I checked in there to see who was doing what and get a better feel for activity. It didn’t take long to start assimilating the nature of the beast. It seems that in Europe, where amateurs in many countries have access to 630 meters, two-way QSOs are taking place on CW and various weak signal digital modes. There is also a lot of beaconing using WSPR (Weak Signal Propagation Reporter) taking place. In North America, since there are so few who can legally communicate with each other due to licensing issues in the U.S., the vast majority of activity is on WSPR. There is some CW and JT9 (another weak signal digital mode), and from time to time QRSS (extremely slow CW meant to be read visually from a “waterfall” on a computer screen). I began checking into the chat site every evening and it was immediately obvious my exploration of these bands would not end with Crossband Night. Hang on. Here we go again!

I have never been much for digital modes. It is no secret I find the inherent reduction in what constitutes a complete QSO these modes have brought very disturbing. WSPR, however, is quite interesting. As the name implies, it is a beaconing mode intended primarily for propagation study and monitoring. Without getting into it too deeply, there is a 200 Hz “window” on each band (2200 meters up through microwaves) where this mode is used. WSPR transmissions are two minutes long each, precisely timed. The information encoded in each transmission is call sign, grid square and power (in dBm) of the transmitting station. One can adjust how often the transmissions are made, from 100% (continuous transmission using every two minute time slice) down to 1%. For example, 25% would mean the software transmits one out of every four two-minute time slices or about once every eight minutes. Usually the slices chosen for transmission are randomized to help alleviate interference among stations or any one station not ever hearing another because they are both transmitting at the same time. On the receiving end, the software monitors the entire 200 Hz segment and decodes any WSPR transmissions it hears. Since WSPR is a very narrow bandwidth mode, many signals can fit into the small slice of spectrum without overlapping. One interesting feature of WSPR is the ability to upload data from all decoded transmissions to the WSPRnet.org web site. WSPRnet provides mapping of activity, showing propagation paths in real time. It also provides access to the database of received decodes, allowing users to extract a variety of information about who is hearing who and how well. The mode can pull signals from deeper in the noise than the human ear, making it possible to receive signals more traditional modes could not. WSPR is worthy of an article in and of itself, so I won’t go into it too deeply here.

Example of a WSPRnet.org map, showing stations being received by N1BUG on the 630 meter band

It wasn’t long before I heard my first signal from Europe on 630 meters. Wow! It would be followed by several others on the better nights. Hawaii also showed up in my decode list on several occasions. This is amazing, considering that most of these stations are running one watt effective radiated power (ERP). They may be running many times that out of the transmitter, but the average antenna on 630 meters is very small compared to a wavelength and quite inefficient, meaning that only a small part of the power fed to it is actually radiated. The rest goes to various losses in loading coils, ground system, etc. Consider that a quarter wave vertical would be 495 feet tall and you can see that physically short antennas are going to be necessary for most of us! I mentioned before that WSPR can pull signals from much deeper in the noise than the human ear. But, at times some of the stronger European stations have been clearly detectable to my ear. I could have copied them on CW.

630 Meters is fun, but I have always been a creature of extremes. The real challenge here was obviously going to be 2200 meters. I wanted to hear a signal on that band! After several nights listening without success I knew I had work to do. Not only were there no signals, but I could not even hear a change in noise when I disconnected the antenna. Either the antennas weren’t working or my receiver wasn’t working at this frequency. Perhaps both. One night while listening on Old Reliable (my 80 meter inverted V), I managed to decode WD2XES in Massachusetts on WSPR and VO1NA on QRSS60. Signals at last! Although neither was detectable to my ear, I at least could claim that I had intercepted and decoded signals on this band. Of course that only made me want more, so I redoubled my efforts.

During the course of investigation I found my FT-2000 is extremely deaf on 2200 meters. It needed a lot of help! I set about building a preamp to bring signals up to a level the receiver could detect. 22 dB gain wasn’t enough, but it did bring up signals in the AM broadcast band enough to cause signal mixing IMD products in my receiver. Suddenly the whole spectrum was a mess of howling, squealing, squawking and wailing from these unwanted mixes. I was going to need a filter to kill the strong signals up in the medium wave broadcast band. So I set about to build one. I have already written an article on that adventure. It was a great learning experience. Then I built a second preamp. Now with 44 dB gain ahead of my receiver I began to routinely hear signals. WD2XES was usually audible; WH2XND in Arizona was easy to decode on WSPR and sometimes just barely discernible to the ear. Even with all this, the FT-2000 still was not good enough at this frequency. I still couldn’t hear any drop in noise floor when I disconnected the antenna. I am now experimenting with a low frequency converter that takes the 10 kHz to 300 kHz spectrum as input and provides output at 10.01 to 10.3 MHz for the receiver. This finally solves my sensitivity problem, and without the use of preamps. It does introduce a frequency drift problem which I am trying to resolve. With the converter, WH2XND is being decoded over 100 times in the average night and is often clearly audible. Progress! As for antennas, on this band I find the southwest Beverage works better than any other. It isn’t quite the same as on 630 meters. Down here this is not the quietest Beverage but it seems to pick up signals better than any other regardless of direction. These wires are less than one tenth of a wavelength long at this frequency. It is a wonder I hear anything.

I mentioned QRSS a couple of times. I find this mode very intriguing. It may well be the ultimate mode for extracting signals from deep in the noise floor. Using a variety of submodes of differing speeds, QRSS can integrate a signal over time, detecting it at weaker levels than anything else I am aware of. Submode QRSS60, for example uses dots of 60 seconds in duration. Dashes are 180 seconds. This is an extremely slow mode. It would take 33 minutes to send my call sign ‘N1BUG’. But it can dig very deep for signals. I would be quite interested in attempting transatlantic QSOs using this mode on 2200 meters, assuming we get access to the band as amateur radio operators.

VO1NA received on 2200 meters using QRSS60 mode. Although the first dash of the letter O is a bit broken up due to a signal fade, you can essentially read his call sign from the screen. This is how QRSS is received.

There is a good amount of activity on 630 meters. It will be very interesting to follow propagation trends as we head into solar minimum. Some say this could be the deepest solar minimum since the invention of radio. Unfortunately I cannot say the same for 2200 meters. Perhaps it is just too immense of a challenge for most, or perhaps what can be done there hasn’t received as much publicity as the higher band. The only stations transmitting regularly on 2200 meters in North America are WH2XND is Arizona and WE2XPQ in Alaska. The latter is practically an impossible path from here in Maine given the high latitude (auroral oval to contend with) and the fact that his antenna is directional and does not favor us. WD2XES in Massachusetts is on some evenings. I have only seen VO1NA once. I wish there was more activity on this band. Actually I wish I was capable of transmitting on the band, but that is another story.

I am continuing to learn about these bands and exploring technology that is new to me. I am learning a lot of things I didn’t expect along the way. In a subsequent installment, I will talk about basic equipment and antenna options, as well as provide ideas on resources for further study. I have spent several hours every day for over a month studying various ways of getting on these bands (particularly 2200 meters). There is a lot of published work out there and some very interesting kit options for equipment.

Filter Project Proves Once Again: “Stuff” Happens!

Leave a reply

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

I’m pretty self sufficient when it comes to problems; I create my own. Every once in a while, though, I get a little outside help…

I set out to build a bandpass filter for the 136 kHz band. Fortunately my junk box yielded all of the necessary parts and it didn’t take long to construct the simple circuit. As an interesting side note, when seeking capacitors for RF projects that aren’t in my “new parts” stash, I usually have to dig through RF boards out of old receivers and/or transmitters. This time, I had to get suitable components from audio boards! That says something about just how low in frequency this 2200 meter band is! In fact, some hams have successfully used high end audio amplifiers as RF power amplifiers for this band!

Since I now have test equipment, I avail myself of it whenever possible. The first thing I did is put my new filter on the tracking generator/spectrum analyzer, expecting to see a lovely bandpass response matching what I had seen in the filter design software. Whoa! Something was wrong. Instead of a flat response in the 100 to 200 kHz range, dropping steadily and steeply above and being nearly 70 dB down at 600 kHz, there was a “peaky” response in the desired range with a very sharp secondary peak at 465 kHz and a moderately steep roll-off above that. Response was down only 43 dB at 600 kHz. I checked return loss (SWR) and that was awful too. What could be wrong?

After verifying the circuit layout and marked component values, I realized I must have a bad component or perhaps the type of capacitors I used wasn’t working well in a filter circuit. I poked and prodded, changed out all of the critical capacitors, but there was no improvement. In desperation I resorted to something which probably isn’t an approved troubleshooting technique: bypassing components with a wire one at a time while watching filter response on the spectrum analyzer. Bypassing any part changed the response, but only one caused the spurious response at 465 kHz to vanish. I wasn’t at all sure this meant anything, but it did seem curious. That part was one of three inductors in the circuit. It, like the others, was wound on a small FT37-43 toroid core. Thinking somehow this inductor was messed up, I wound a new one using a different type of wire. This still didn’t change anything.

After much head scratching and pondering, I was running out of ideas. The only thing that made any sense was that somehow that inductor was the wrong value. But how could it be? Since nearly all of the different ferrite mixes (materials) used in these cores look alike, it was theoretically possible that a core of some material other than #43 had worked its way into the bag. That didn’t seem likely since this was a still sealed bag of cores I bought from a major supplier some time ago but hadn’t used until now. Nevertheless, it was worth investigating the possibility since I had no other clues.

I went back to the filter design software and began experimenting with different values for this one inductor. It was supposed to be 47 microhenries. I found that if I changed it to 8 microhenries in the filter designer, the calculated response was almost exactly what I was seeing in the real world on my test equipment. Interesting! The question then became whether the same number of turns it takes to get 47 uH on a FT37-43 core would yield 8 uH on an FT37 size core of some other material. Lo and behold! The same number of turns on a core of #61 material gave exactly that much inductance! It was starting to look as though I might be on to something with this “wrong core” theory. Most of my theories aren’t as promising.

I wound a new inductor using another core from the same lot and put it into the circuit. Nothing changed. I tried another with the same result. Then I decided to get serious. I calculated how many turns it would take on a #61 core to get 47 uH, and wound one accordingly. I had to use really small wire since a much larger number of turns was required. With this inductor the filter response changed to what it should be! I did indeed have some #61 cores in this lot of supposedly #43 cores! Further investigation (involving a lot of coil winding and soldering) revealed that the lot of cores were about a 50/50 mix of the two types. I swear this was a sealed bag from the supplier until I opened it to make this filter. Either the supplier or the manufacturer must have got some #43 and #61 cores mixed up.

In the end I have a perfectly working filter with flat response and less than 1 dB insertion loss across the 100 to 200 kHz passband, rolling off steeply on either side and reaching -70 dB at 600 kHz. It continues to roll off steeply, reaching almost -90 dB at 800 kHz. Return loss in the passband is good at -20 dB or better. The circuit board and construction technique is crude but at this frequency it just doesn’t matter. One of the nice things about building and experimenting in this part of the radio spectrum is that you can get away with a lot of sloppiness. You cannot get away with a 600% error on inductor values in a filter, though. Well, maybe you can if you don’t mind using a relatively poor filter.

I questioned the wisdom of investing in test equipment a few years ago. I really couldn’t afford it. There are still times I wonder if I can afford to keep it. But it has saved by sorry butt more times than I care to admit! I often wonder just how I got by all those years without it. Skill? Luck is more likely! I don’t see how I would have spotted this problem without the test equipment. Undoubtedly I would have placed the filter in service assuming all was well, and never known that it was not performing as intended.

September VHF Contest 2016: More Fun With a Small Station On 2 Meters

Leave a reply

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

I could have titled this ‘Feast or Famine: What a Difference a Day Makes’. That’s how it is with VHF. Conditions can change quickly. If there is a secret to success, it lies in knowing the ups and downs of propagation – both short and long term – and developing operating techniques tailored to take advantage of opportunities. This is a very different world from HF.

Despite variable conditions, my final VHF contest with low power (barring unforeseen disaster) was the best yet. This contest saw a marked shift in conditions from well above average Saturday to well below average Sunday. My two meter station remains 25 watts to a very short seven element yagi. The boom length of this antenna is less than six feet. I am using low loss cable, but with 350 feet of feedline to the antenna, I lose at least three dB on transmit and receive.

Conditions Saturday were quite good. There was clearly some tropo, but not something I would characterize as a great opening. I would call it ‘high normal’ propagation. What is unusual is getting anything above average during a contest weekend! I worked 27 stations in 18 different grid squares between 2:00 pm contest start and 10:00 pm when I shut down for the night. I was not at it continuously. I took several breaks during this period. When I was operating I kept the VFO constantly moving, tuning 144.150 to 144.250. VHF contesters turn their antennas a lot, and propagation peaks play a significant role. Success requires vigilance in finding stations. You not only have to find them, but you have to find them at just the right moment. You can tune the band 10 times and hear nothing, and on the next pass find a booming signal (or several). I also worked two new states (New York and New Jersey), bringing my total in just over three months of rather casual operating to 13 states and four Canadian Provinces. The best peak was around sunset, when I worked three stations at about the 450 mile mark. Two of these were without any form of coordination or advance notice. I heard the stations calling CQ, called them, and worked them. What a thrill that was! I could hear several stations around 500 miles but was not successful in working them.

Sunday morning a cold front moved through the region, wiping out any remaining tropo. The band was noisy from lightning associated with storms along the frontal boundary. Nevertheless, with conditions now clearly below average I was still able to copy some big stations at and just beyond 500 mile range. QSOs Sunday were hard to come by but this does not mean nothing could be worked. Despite poor conditions, at times there were very good, workable signals to 300 miles or more. The trouble was I had worked those stations on Saturday. Winds associated with the storms and behind the front aggravated a source of power line noise to my southwest which I have not been able to track down. I spent much less time operating after that.

I ended up working 29 stations in 18 grid squares on two meters. Many operators thanked me for FN55, saying it was a new one for them in this contest.

I placed no emphasis on six meters. I only went there when asked to QSY by someone I worked on two meters. On six I worked 12 stations in nine grid squares. I was running 100 watts to a 7 element, 33 foot boom yagi on that band.

Finding VHF Weak Signal Activity

Leave a reply

This is one of a series of “Notes” I published on Facebook. Since Facebook has discontinued the Notes feature, I am publishing that series here on my blog.

VHF DXing is different from HF in several important ways. One of the most obvious is propagation. At VHF we don’t have propagation around the globe and what we do have tends to come and go on a whim. Everyday troposcatter conditions allow the small station to work 150 to 300 miles and big stations up to 500 miles. Beyond those limits we are faced with waiting for opportunities. Another factor is antenna directivity. Most two meter and up stations use multi-element yagi antennas which are very directional. Beyond “local” range of 150 miles or so, it is usually necessary for both stations to have their antennas pointed at each other. Sometimes this happens by coincidence but often it doesn’t. Many VHF and up contacts are the result of scheduled attempts.

So how do we find each other and make the most of propagation opportunities? In the old days it was HF and the telephone. There were widely known meeting places on the HF bands where VHF activity could be coordinated. For example, during every major meteor shower, 3.818 MHz on the 80 meter band was a hot bed of activity. Many people wanting to find a station to “run” with on VHF would put out a call there and see who responded, or reply to another station who announced his availability there. 14.345 MHz was widely used for scheduling and discussing all types of VHF weak signal activity in Europe, and was used for the weekend EME nets where schedules were made worldwide. Often, avid VHF operators would call each other on the telephone to arrange a meteor scatter schedule or to try an impromptu contact during a tropo, aurora, or sporadic E opening. We also had something called activity nights. Monday evening everyone got on 2 meters and made noise on the calling frequency, 144.200; Tuesday it was 222 MHz, Wednesday 432 MHz, and so on.

Today, the telephone and HF are still used, but to a much lesser extent. Email lists or groups (“reflectors”), social media pages and groups, and internet chat sites have become the primary means of coordinating VHF activity. There are general forums and specific ones aimed at various aspects of VHF+ operating: digital modes, non digital modes, meteor scatter, contesting, EME, etc.

Not everyone has time to keep up with half a dozen active email groups, and most beginners aren’t going to be doing EME or meteor scatter right off the bat. I usually recommend ON4KST Chat as a starting point for those wanting to explore what is out there. It is easy to register and you only log in when you want to. All you need is a web browser. ON4KST has chat pages for 6 meters, 2 meters and up, microwave, EME, and low bands (160, 80 meters). People there are very friendly and willing to help newcomers to the game. The 144/432 MHz Region 2 chat page, for example, is used by North American stations wanting to coordinate activity or discuss topics relevant to DXing on 2 meters and 70 centimeters. This morning I checked in there and found W3BFC and KA1ZE/3 wanting to try working me on 2 meter CW. Via the chat, we picked a frequency and discussed any relevant particulars about who was going to transmit on 2 meters when (such as me transmitting during even minutes and the other guy during odd minutes). Six digit grid squares are listed on the chat; clicking on one causes the server to tell you the distance (in kilometers) and beam heading, so we knew where to point our antennas for the attempt.

Not everyone is comfortable with these tools, but I find them to be a great resource in the modern age. I am always interested in “testing the limits” to see how far I can get on VHF. Arranging QSO attempts in the various forums available allows me greater opportunity to maximize both opportunities and success. For me, this greatly increases the “fun factor”. Only the means is new. VHF and up contact attempts have been arranged and coordinated by other means since the early days.

A few words about etiquette may be in order. It is fine to set up a time, frequency, and calling sequence for a VHF or UHF QSO by means of these forums. It is OK to change those details during a QSO attempt via the chat room; for example, asking the other station to change frequency if you have QRM. However, exchanging details of an ongoing QSO attempt on the chat invalidates the contact – or at least it should. For example, if I am attempting to work VE7BQH on 2 meters and I say to him on the chat site “I am sending you a 559 report”, I have just invalidated the contact. The signal report should be part of the amateur radio QSO, sent and copied over the air, not via the chat room! As with any other aspect of the hobby, you will see some people violating this long standing ethic. In the end, we are each responsible for our own ethics. Those who take the easy road are only cheating themselves. Again, it is the QSO details (signal report, “rogers” or other acknowledgement) which should not be given by any means other than over the air on the band you are trying to make a contact on.

You can find the ON4KST chat site by starting here: http://www.on4kst.com/chat

I could make a case for the chat being the only tool necessary to know when the bands are open. If there is unusual propagation, chances are the avid VHF operators logged in there know about it and are all abuzz making the most of it! However, I still find VHF propagation tools useful. For example, the APRS-derived propagation map found at http://aprs.mountainlake.k12.mn.us is a good way to spot potential 2 meter openings. It works well for tropo and sporadic E, but not for aurora (because auroral propagated signals are too distorted for APRS to decode). It is not the “last word” on whether the band is open. False positives can occur from meteors which are long gone by the time the map updates. Lack of APRS stations in specific areas can sometimes lead to the map not showing much when in fact some path may be open. Nevertheless, I find it quite useful. (Note: This map is supposed to automatically update every few minutes, but it often stops on all of my computers and browsers if I leave it open for a while; I click the refresh button every so often as a reality check to see if it has gotten stuck.)

Another (this one from the shameless plug department) is Aurora Sentry at http://www.aurorasentry.com. This takes a little more experience to navigate and interpret, but has been my tool for spotting VHF aurora openings since 1997. Sadly, as of this writing it is in need of a re-work. Data sources come and go.

Whatever your preference, the more activity we get on the VHF bands the better. It’s always a good idea to put out a CQ on the calling frequencies from time to time, but non-VHF and non-amateur radio means of arranging VHF QSO attempts can definitely add to your success.