Category Archives: VHF+

Perseids 2017 on 144 MHz

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

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

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

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.

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

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

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.

Remembering The EME Years

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.

As I watch the moon sinking low in the southwestern sky, shimmering through the trees I am reminded of an evening long ago. It was May 29, 1988 and I was running a two meter EME (Earth-Moon-Earth, or “moonbounce”) schedule with W7IUV in Arizona. The moon was in about the same position it is now, my single CushCraft 4218XL yagi looking at it through the trees, and I was pumping about 1000 watts of CW into the antenna, alternating two minute periods transmitting, two minutes listening. Perhaps I should emphasize listening. During receive periods I was tuning up and down through a narrow range of frequencies, about one kilohertz total, hoping to find some hint of a very weak CW signal at the noise floor. Eventually I did find it, and from time to time could even copy it. Back and forth we went, exchanging callsigns, signal reports and acknowledgement of information received according to a special format. I completed the contact with Larry that evening for my eleventh station worked via the moon. My first EME contact had come six months earlier when I worked superstation W5UN on December 26, 1987. That was the beginning of the most exciting phase of amateur radio I ever experienced.

I had started on 2 meters in the summer of 1986, after picking up a used all mode radio at a hamfest. I made a lot of contacts on the terrestrial propagation modes: troposcatter, sporadic E, aurora, meteors. But I was reading everything I could get my hands on about VHF DXing, and I knew EME was king. While the terrestrial modes allowed contacts to a distance of 1400 miles on occasion if one was lucky, the whole world was within reach by bouncing signals off the lunar surface. EME was all CW in those days and it required quite a bit of power. I could have probably worked W5UN with 100 watts or so, but I knew if I was going to work more than one or two of the very big stations it was going to take more. I set about collecting parts to build a kilowatt amplifier.

By the fall of 1987 the new amplifier wasn’t quite ready yet but I had upgraded the antenna a couple of times, now having the 29 foot long CushCraft on a 40 foot tower. I could not elevate the antenna above the horizon, but I listened at moonrise during the ARRL EME Competition in October and November of 1987. I heard several stations including YU3WV. Wow! I was hearing Europe on two meters! I couldn’t wait to make my first EME QSOs!

I am not sure how I survived the first contact with W5UN, because I don’t think I breathed during that schedule! Dave had the largest EME antenna in the world at the time, a truly massive structure comprised of 32 long yagis stacked four high and eight wide. That first contact was followed the next day by working N5BLZ with his array of 12 long yagis. A few days later I worked K1WHS which was interesting because we were just 150 miles apart. Pointed at the rising moon I could hear Dave’s tropo signal quite strongly off the back of my antenna. He was hearing me direct as well. But from time to time, shifted some 350 Hertz higher by the relative motion of the moon to our antennas (doppler shift), the EME signal rose just above the noise floor. It was bizarre. Not only was the lunar echo shifted in frequency, but it wad delayed by almost two and a half seconds. That is how long it takes a radio signal to traverse the half million mile round trip to the moon and back. Dave was literally QRMing himself! Instinctively we both began to send two or three letters and then pause for the echo to return. This was to prevent the tropo signal from overwhelming the weaker moon echo and give the other guy a better chance to copy the wanted signal. After all, we were trying to complete a QSO by way of the moon, not tropo! It was easy to tell one signal from the other by the frequency.

Left: “The Ugly Kilowatt” pair of 4CX250Bs’s, with all-mode 2 meter rig sitting on top; Right: Amplifier with three 4CX250B tubes that never did work quite right. In the middle, Kenwood TS-820S with Microwave Modules transverter which I was using on EME at this point in time.

A month later I worked my first two Europeans on 2 meters, SM7BAE and UA1ZCL. I had worked Europe on two meters! EME became the thing to do. Several others followed, and by the spring of 1988 I installed a receive preamp at the top of the tower, just below the antenna itself. This would allow me to hear the very weak EME signals a little better, and it paid off. I soon worked the smallest station to date: four yagi station KI3W. All told, I worked 16 different stations off the moon with my single yagi. I was hooked.

By October, when the EME Competition came around again, I had completed construction of a real EME antenna: 16 four-element quads which I assembled from strips of wood and wire from the local hardware store and lumber yard. There was no stopping me now! This antenna had 19 dB gain, or about 5 dB more than the CushCraft yagi. It made a huge difference. EME contacts were now much more numerous and I could elevate the thing so I was no longer limited to short windows at moon rise and set. For the first time I could hear my own lunar echoes come back. That in itself was a thrill!

The 16 quad array

The first amplifier, a pair of 4CX250B tubes, gave way to a legal limit-capable 4CX1000A. The KLM Multi-2700 transceiver got replaced by a Microwave Modules transverter in conjunction with my Kenwood TS-820S HF rig. The antenna was upgraded to 24 of the little quads, producing about 20.5 dB gain. As operator skill and confidence grew and the station slowly improved, running pre-arranged schedules gave way to what we called random operating. In other words, calling CQ and working whoever you could get. Or tuning the band looking for other stations calling CQ. By the end of 1994, 520 different stations had made their way into my two meter EME log. After a period of inactivity due to changes in living arrangements, I returned to EME in 2000. My final two meter EME QSOs were made in 2006 just before leaving the band. By then, digital modes had largely supplanted CW and EME via digital wasn’t much of a thrill. My two meter EME “initial” count, or number of different stations worked, had risen to 610. I also had a brief stint on 70cm (432MHz) EME, first with a single 22 element yagi, later an array of eight 21 element yagis. I worked 33 different stations via the moon on that band but never liked it as much as two meters. I made one and only one EME contact on 6 meters.

A later version of the station. Left to right: HF amplifier with four 811A tubes; “Ugly Kilowatt V2” 2 meter amplifier using a 4CX1000A; Kenwood TS-820S and transverter; Color Computer II running MoonTrak. Mounted on the wall above the Kenwood, azimuth and elevation controller for the EME antenna

EME also led me to take up computer programming. I wrote three programs for tracking the moon. First a very simple azimuth-elevation calculator for the Radio Shack PC-3 Pocket Computer; next, MoonTrak real-time azimuth and elevation tracker with polarization calculation for the Color Computer II; finally Z-Track for the IBM PC. For a time I sold copies of the latter to fund my EME addiction. My EME software was the first to incorporate calculations of “spatial” polarization offsets between stations and take into account the implications for EME scheduling. Later I collaborated on a rewrite of the EME scheduling database software used by the Two Meter EME Net.

Z-Track software. Note the year, 1996. This software was running under the MS-DOS operating system!

There is no way to describe what EME meant to me. The sheer thrill and excitement of it cannot be conveyed. It was the ultimate challenge, the ultimate DX, the ultimate accomplishment. Nothing I have done in ham radio before or after EME can compare. Not a day goes by that I don’t miss it. Ultimately it was the collapse of CW on EME that led to me leaving VHF for a decade, returning just this summer. If I wasn’t so constricted by budget I would no doubt build a large antenna array and return to two meter EME for the few CW QSOs which can still be had occasionally.

Two Months and Eleven States: My Experience With ‘Small Station’ DXing on Two Meters

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.

Not long ago I wrote a primer on VHF and UHF DXing. In it I outlined what one could expect using a 50 to 100 watt station and 8 element or larger yagi on the two meter band. Since then I have been operating with 25 watts to a seven element yagi with interesting results. This isn’t even an optimized seven element antenna; it is on a very short boom for this number of elements, about six feet long. Performance is about on par with most four or five element yagis. I would like to share my experience.

I operated the June VHF Contest with the little yagi at a height of 27 feet, just below my six meter yagi. I had a very high noise level and the yagi exhibited minimal directivity. I would later discover this was caused by proximity to the much larger six meter yagi. I was able to work five states: Maine, New Hampshire, Massachusetts, Vermont, and Connecticut. The longest distance worked was 345 miles. Tropo was typical of “every day” conditions, nothing special. The weather was somewhat windy across New England, which prevents significant tropospheric propagation enhancement over average daily levels.

Not long after that contest, I moved the yagi to the top of my main tower at 105 feet above ground. It is still near a large antenna, in this case being just five feet above my TH-11DX five band HF beam. Nevertheless, reception was much less affected by local noise and the little two meter yagi exhibited better directivity, indicating it was not as disturbed by its neighboring antenna. In the CQ VHF contest I was able to work most of the New England states again, with the longest distance again being 345 miles. That is about the limit for this size antenna and 25 watts without some serious tropospheric propagation enhancement or other propagation mechanisms. The notable difference is that now I was hearing stations out to 450 miles, which did not happen with the antenna in its former location.

In July I caught two sporadic E openings, working Kentucky, Tennessee, South Carolina, and Georgia with best distance being 1200 miles. No one can say for certain, but given the distances and nature of sporadic E it is quite likely I could have worked all of the stations with the antenna at much lower height.

Taking advantage of the Perseids meteor shower, special operating techniques and the FSK441 fast digital mode designed specifically for VHF meteor scatter I was able two work two more states: Virginia and Wisconsin, with best distance 1013 miles. This is not an easy game with a station of this small size, but I proved it can be done if one has patience and persistence. One of the hardest things is getting stations to try to work you. Most are afraid they won’t be able to hear such a low power signal, and random operating (eg. calling CQ vs. having a pre-arranged schedule with a particular station) is not going to work at this power level. My antenna was probably too high for optimum results on meteor scatter. I might have done better with stations in the 700 to 1100 mile range had it been lower, where it could offer a bit more relatively high angle radiation.

In two months of mostly casual operation, being aware and mindful of VHF propagation I was able to work 11 states on two meters. Given a couple of years, a bit of luck with propagation and some effort, another 11 or 12 states are definitely within reach. If sporadic E were to be very cooperative or there were to be a massive aurora which spawned auroral E, another three or four states are possible. I believe my experience demonstrates that VHF DX is not beyond the reach of modest stations. My results were probably better than those of a newcomer to the game, since a previous 20 year period of working two meters has made me a savvy operator, very aware of propagation mechanisms and how to spot opportunities. Propagation awareness is critical for success on VHF.

There was no aurora during this period, but contacts to at least 900 miles on that mode are definitely possible with a station of this size. However, CW is a requirement for aurora.

It should be noted that graduating to the 100-150 watt class, easily within reach of most with a modern transceiver or solid state “brick” amplifier, will greatly enhance results. I would recommend this to anyone wanting to be serious about VHF “DXing”, though obviously it makes sense to start out with whatever power one has and upgrade once the desire for better results sets in. A larger antenna is always better, but even a very short yagi can provide interesting results. If erecting a long yagi is not practical, consider two or four short yagis properly stacked and phased. It’s not as difficult as it may sound, and you will find experienced VHF operators happy to assist.

2 Meter SSB/CW Operating Primer

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 recently written about what can be done on the two meter amateur band using modes other than FM. In a recent VHF contest my 25 watt station using a very small yagi mounted in a poor location at 27 feet above ground was able to make contacts to a distance of 350 miles. One should not expect ragchew quality with such a station at that distance, but short exchanges are possible. Reliable ragchew or conversational range with a small station on SSB will be 100 to 200 miles depending on numerous factors. The small station can expect occasional contacts to 1000 miles or more if the operator is alert and understands VHF propagation. As station power and antenna gain/height increase, so does typical working range. Far greater range may be had with a small station operating portable from a mountaintop.

A few of us hope to promote greater local activity in this interesting facet of amateur radio. I thought it would be useful to talk a little more about operating on the low end of the two meter band using SSB, CW, and digital modes. It is very different from FM and repeaters.

This is not like the HF bands which enjoy high activity and constant or frequent propagation. Beyond the normal working range of 100 to 500 miles depending on station capability, propagation is very infrequent and sporadic. The band can go from closed to open and vice versa in seconds. Propagation footprints can be very small with one station making DX contacts 1200 miles out while his neighbor ten miles down the road hears nothing but the locals. Furthermore, highly directional antennas are the norm. This makes it easy to miss signals coming from any direction other than where your antenna is currently aimed. Except in a VHF contest or when the band is known to be open for long distance communication, tuning around looking for signals is generally pointless. So how do we find someone to talk to? How do we prevent our extended local conversations from thwarting our neighbor’s attempts to make calls or long distance contacts if the band suddenly opens up? These are important considerations. The answer lies in understanding proper use of a calling frequency.

The established SSB and CW calling frequency on two meters is 144.200 MHz. This is where virtually every station who wants to call CQ (except in major band openings or contests) will go to do so. This is where you want to call CQ and also where you want to monitor for activity. Why do we call it a calling frequency? Because it should be used for making calls, but not for conversations or extended operating. If we all use the calling frequency considerately in the manner it was intended, we can maximize fun and enjoyment for everyone. If you establish contact with another station and want to exchange more than a signal report and a couple of brief remarks, proper etiquette is to move off the calling frequency with the station you are in contact with. This leaves the calling frequency open for others to make calls and for your neighbors to monitor for unusual band activity including DX opportunities. FM should not be used here, as it has the potential to seriously interfere with SSB and CW operations that you cannot hear on an FM radio.

How long of an exchange is considered acceptable on the calling frequency before moving off? How far off the calling frequency should you move for an extended QSO? These are good questions! I like to QSY off the calling frequency if I am in contact with another station for more than a minute or two. As an experienced two meter operator and DXer, I suggest this as a reasonable rule of thumb. As for how far to move off frequency, that is a little more complicated. Bear in mind that your signal can be extremely strong with your “local” neighbors – those within 50 miles or so of you, perhaps more with hilltop locations or high power. Not every receiver can handle such strong signals without some overloading. Meanwhile, signals from outside the local area that your neighbors may be trying to hear are likely to be very weak. With those considerations in mind, to minimize the potential for interfering with neighbors I suggest moving at least 20 kilohertz away from 144.200. More may be even better.

There are exceptions. Occasionally (OK, rarely) the band may suddenly open and permit even small and moderately equipped stations to make contacts to many hundreds of miles. Under these conditions the rules of etiquette change to permit everyone a reasonable chance of making DX contacts. When the band is really open, there may be many stations CQing and making brief contacts, taking advantage of the DX opportunity while it exists. Chances are operators at the other end of the propagation will be tuning around the band to find stations to work, but they probably won’t tune a huge portion of the band. In cases where the band is obviously open and activity is high, it is still considered impolite to hog 144.200 for extended periods. “Running” a few QSOs there is OK. Beyond that, try moving off a few kilohertz and calling CQ; perhaps up or down five if this is an opening where most are running SSB, up or down two if it is mostly CW (such as would be the case with aurora propagation). If it is really crowded, move off to the first clear frequency you find above or below the calling frequency.

Generally speaking, digital modes are not used on 144.200. There are special calling frequencies for certain types of digital mode operating. For example, 144.140 is used for calling using the FSK441 mode for meteor scatter communication. There are highly specialized operating techniques and special etiquette for this, which is beyond the intended scope of this beginner article.

Let’s get back to everyday operating for a moment. From our area, most signals on an everyday basis are going to be either local (try pointing antennas toward the Bangor area, but look around with the antenna too, so those in outlying areas have a chance to hear you) or from the southwest direction. There is a “VHF alley” (sometimes called “kilowatt alley”) of activity down the coast… southern Maine, southern New Hampshire, Massachusetts, Connecticut, Rhode Island, eastern New York, New Jersey, and so on. This is where most of the non-local signals come from except during long range band openings. Southwest is a good direction to “park” your antenna for listening. Occasionally you may get someone from the west or the east (Canadian Maritime provinces), or even north. Put out a CQ in those other directions from time to time. You may make someone’s day, as they are in areas often overlooked!

Activity tends to concentrate in the evenings. Try 1900 to 2100 local time. Not only is this a convenient time for many people, but tropo conditions often peak up a little around that time, permitting better signals from moderate distances. Sometimes there is a good peak in conditions around dawn and shortly thereafter. The problem with that is lack of activity. There is a group well to our southwest that gets on 144.205 in the mornings. Some of those stations are occasionally joined or worked by stations in our area. I believe some of them also monitor the appropriate ON4KST chat page in the mornings. Speaking of which, the chat can be a good place to find people a few hundred miles away who may be interested in trying to make contact with you on two meters! Give it a try. People there won’t bite, but I can’t promise they won’t growl about poor propagation!

Lastly, a final word on calling frequency etiquette. If you find others ragchewing on the calling frequency, please consider asking Lastly, a final word on calling frequency etiquette. If you find others ragchewing on the calling frequency, please consider asking very politely and tactfully if they could move off. Many do not realize or forget that tying up the frequency with extended conversations can rob other stations of the opportunity for rare and exciting contacts or just the chance to put out a CQ call. Some may feel that talking for long periods of time there is a good way to attract attention. It may be! But, it also gets in the way of others enjoying the band. Please, let’s all consider each other’s enjoyment of this very different and exciting facet of our great hobby. See you on the low end of two meters! (Note as of July 8, 2016: I am not really active as of yet; I need to finish antenna projects before I concentrate on operating and trying to encourage more activity. Give me a few weeks.)

The ‘Other’ VHF/UHF in the Maine Highlands

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.

Most new hams these days start out on VHF FM and repeaters. Radios are inexpensive and simple to operate. Antennas are small and readily available or easy to build if one is so inclined. Many may never experience any other aspect of ham radio. Those who have entered the fraternity partly or wholly for the hobby aspects of it may get on the HF bands where contacts around the world are an everyday occurrence. Few will ever realize or experience the potential of VHF and UHF using non-FM modes. This ‘other’ VHF/UHF may be one of the best kept secrets in ham radio today.

In Maine, VHF or UHF FM will allow one to communicate up to 50 miles or so between base stations, maybe more if one or both stations are located on hilltops. Operating through repeaters this range is doubled. A few repeaters, especially those located on higher summits, may allow communication between stations up to 150 miles apart. Occasionally, when atmospheric conditions are favorable, the range may be extended. There are linked repeater networks and repeaters linked via the internet which allow long range communication but such contacts are not generally useful for awards or contests and for many, simply don’t provide the same thrill as a radio-to-radio contact without any active devices (repeater, internet, satellite) assisting. There is something inherently fascinating, something often uniquely rewarding, in using natural phenomena to get one’s radio signal to a far-off place.

When we start using modes other than FM – such as SSB, CW and a host of digital modes that work through SSB transceivers – we enter a whole new world on VHF and UHF. This is a world known as VHF “weak signal” communication, but the term can be misleading. Sure, sometimes signals are weak but they can also be extraordinarily strong. Although I am not familiar with the etymology of the term, it may refer to the fact that the non-FM modulation modes can make weaker signals usable where FM would fail. So just what can we do with VHF and UHF once we look beyond FM? Once we get into the VHF range we start to find other methods of signal propagation over relatively long distances; ones that are not useful on the HF bands. The troposphere (the lower region of Earth’s atmosphere which is largely responsible for our weather) has a significant influence, and certain less common ionospheric phenomena come into play. VHF and UHF weak signal communication is almost always done using directional or beam antennas, the yagi being the most popular. Unlike FM and repeaters, horizontal polarization is used. Vertical polarization may have been chosen for FM work to simplify hand held and mobile antenna setups, or because it is easier to achieve omni-directional patterns. Horizontal polarization has certain advantages, among them less susceptibility to many types of man made noise; hence it is a good choice where we may be wanting to copy signals that are not strong. Horizontally polarized beam antennas are also easier to mount without the (usually vertical) support mast degrading performance of the antenna. What is possible on VHF and UHF “weak signal” is influenced by regional weather, terrain and other factors. As a result, this article focuses on what to expect if you live in the Maine Highlands region. This is based on more than 20 years experience. For purposes of this article, the assumption is made that your station is located in a moderate valley, as most of us are. If you happen to live on a hill, you will see better results.

Let’s look at the 6 meter band first. A typical 50 to 100 watt transceiver and a small beam antenna (say, three to five elements on a six to 15 foot boom) will allow contacts to well over 100 miles most of the time. Occasionally this range will be extended by conditions in the troposphere which result in greater signal bending beyond the normal radio horizon. During late Spring through mid summer, the E layer of the ionosphere often becomes ionized enough to reflect 6 meter signals back to Earth. This results in signals propagating over distances to 1400 miles on a single hop, often with excellent signal strength. The band may become full of signals and large numbers of contacts are possible. Less frequent but not uncommon is multi-hop Es propagation. There are usually several good openings from our area to Europe and to the west coast every year during this period. There is a secondary Es season in December-January but more than one hop is relatively uncommon. Aurora can easily reflect 6 meter signals. This is like playing billiards – the signal reflects off the aurora. Typically antennas will be pointed somewhat east of north to work stations to our east, due north to work stations north or south of us, and somewhat west of north to work stations to our west. Contacts out to 1000 miles are common, but greater distances to 1300 miles are occasionally possible. Signals propagated by this method have marked distortion. Single sideband voice may sound very raspy or like a loud whisper. CW signals usually exhibit a buzz or hiss sound rather than a clear tone. Sustained aurora may lead to patches of Es forming and a conversion to auroral Es propagation, wherein the distortion goes away. Meteor scatter, using specialized operating techniques, allows contacts to distances of 1300 miles almost every day of the year. Meteor scatter is of no use for rag chewing but callsigns and signal reports can easily be exchanged. During the peak of intense sunspot cycles, propagation over great distances (even worldwide) is possible using the ionospheric F2 layer, as on the HF bands. There was very little 6 meter F2 propagation during solar cycle 24 due to its relatively weak maximum.

What about the 2 meter band? Using 50 to 100 watts and a multi-element yagi (8 or more elements on a boom ranging from 10 to over 30 feet in length), contacts to 200 miles are possible most of the time. Being in a particularly deep valley will reduce range. Tropospheric enhancement is more common than at lower frequencies, and will at times allow contacts to 300 or even 400 miles. While far less common than at 6 meters, Es propagation does occur on the 2 meter band, usually in June, July or early August. Es contacts to 1300 miles can be made, often with extremely strong signals. In one such opening I worked a station in North Carolina who was running a two watt portable SSB transceiver with its built in telescoping whip antenna. He was blasting in just like a local station! Double hop Es has been reported on a few occasions but is rare. I had one contact at a distance of 1700 miles on double hop Es during my years on 2 meters. Aurora also works well at 2 meters, allowing contacts to 1000 miles and occasionally more. Distortion is even more pronounced at this frequency, usually rendering SSB unintelligible. CW is definitely the preferred mode for 2 meter aurora contacts. Using specialized techniques, meteor scatter works well but is not as easy as it is at 6 meters.

At 135cm, tropospheric propagation is slightly better than at 2 meters. Aurora still works reasonably well. Meteor scatter is possible but quite a bit more challenging. Es is extraordinarily rare but does occur on the order of once every ten years or so! What a thrill it would be to catch an opening like that! I never did.

At 70cm, tropo works quite well. Aurora is somewhat less common than at lower frequencies but can work well during the more intense events. Es does not occur at all, and while meteor scatter is possible it represents a rather extreme challenge.

The bands above 70m are barely used at all in Maine except for a very small number of avid VHF/UHF and microwave contesters. There is so little activity that getting on these bands rarely is worthwhile unless one is an avid contester, has some specific goal in mind, or wishes to explore the fascinating world of microwave propagation.

With high power and larger antennas, other propagation modes come into play. EME, or Earth-Moon-Earth, allows communication with any point on Earth by bouncing signals off the lunar surface. I worked all 50 states and more than 80 countries on 2 meter EME back in the 1980s and 90s when this was all done on CW. One fascinating aspect of EME is that it takes approximately two and a half seconds for a signal to traverse the half million mile round trip to the moon and back. You can actually make a short transmission and then hear your own signal come back from the moon! Tropospheric scatter often allows communication to 1000 miles or more on 6 and 2 meters for stations with a kilowatt of power and high gain antennas (7 element yagi or more on 6 meters, array of four or more long yagis on 2 meters). When I had 1500 watts and a 96 element stacked quad antenna array on 2 meters, I could often work stations up to 1000 miles distant using this brute force propagation mechanism. There is something satisfying about working a station 1000 miles away on a band “everyone knows is dead”. High power and large antennas also extend the range of propagation modes previously discussed. On 6 meter Es I have worked as far as Bahrain, Brazil, Hawaii, and Japan. I have more than 120 countries on 6 meters, all but one or two of them by way of Es propagation. It can be done.

There are several popular VHF/UHF contests. Contesting on these bands is very different from contesting on HF where there are many loud signals all the time. On VHF and UHF you may tune up and down the band(s) for an hour without hearing a signal. When you do find one, you may want to “run the bands” with that station, making arrangements to go from band to band to band, working the station on as many bands as you can. It is both fun and challenging. My first experience with VHF contesting came shortly after I purchased my first 2 meter all mode rig at a hamfest in the 1980s. I had not yet put up a horizontal antenna. I had 90 watts to a quarter wave ground plane I had been using for local FM work. Despite the incorrect polarization making my 90 watts sound more like one watt, I was able to eke out contacts with stations 15o miles away. This opened my eyes to the world of weak signal work and made me want more. It wasn’t long before I made station improvements!

In fact, any operating on VHF/UHF weak signal is different than HF. It’s usually not as easy as turning on a radio and making dozens of contacts. It takes time and patience. Knowledge of VHF/UHF propagation helps tremendously, as you will know when and where to look. On the other hand, the rewards can be great. It is fun to make contacts most hams would believe impossible. There is often a good deal more thrill and satisfaction in making a contact using a rare propagation mode that one must wait for, as opposed to being able to turn on a radio and do it virtually any time.

Cover photo: Temporary VHF/UHF antennas at N1BUG, shortly after a move in 1999. Bottom to top: 13 element horizontal yagi for 2 meters (partially visible); 5 element vertical yagi for 2 meters; 11 element horizontal yagi for 135cm (222 MHz); 22 element horizontal yagi for 70cm (432 MHz) with receive preamp covered by a sandwich bag! The 432 MHz yagi, with approximately 600 watts of power and the preamp shown was enough to work a few dozen stations and all continents on EME, using CW! These antennas were on an azimuth/elevation mount so they could be pointed anywhere in the sky, not just toward the horizon.

An eight-yagi 432 MHz EME array at N1BUG. This array used open wire phasing lines instead of coax to keep losses to a minimum.