Category Archives: VHF+

2021 Antenna Rebuild: The Complete Story, More or Less

I have a passion for radio, but it goes deeper than a hobby for me. As I continually struggle to maintain my relative independence amid the challenges of some very frustrating and debilitating challenges, it is a survival tool. To that end it is important enough to be among the highest priorities in life. Thus when misfortune struck I put much on the line to recover.

Over the past several years, with sacrifices on my part combined with generous contributions from fellow hams I have been on a station building spree. I got back into VHF/UHF weak signal work, greatly improved my HF antennas, and for some time was heavily into experimenting and attempting to work DX on 2200 meters. Things were going very well but all of that changed one winter night in December, 2020. We had a wet, sticky snowstorm that night. All of my wire and yagi antennas were heavily burdened with snow. At some point the strain was too much for the 2200m T antenna that was suspended between my two 100 foot Rohn 25 towers. It broke at one end and fell. The sudden reduction in side loads on the towers caused them to move slightly. With the burden of extreme weight of the snow, this caused significant, but fortunately not catastrophic damage. Some yagi elements were bent, traps damaged, coax cables damaged, masts bent just enough to bind, and one Rohn 25 top section was bent slightly, causing rotation to be extremely impaired on that one. All of the antennas from both towers were going to have to come down for repairs to themselves and the towers.

Side view of the 2200m antenna before the incident. It is strung from a point 103 feet up a tower on the right, and 95 feet up the tower on the left. That three wire top hat can accumulate a tremendous snow load under the right conditions.
Another view of the 2200m top hat, taken from one of the towers. Failure occurred when the antenna broke free of an insulator at one end.
Base and coil platform for the 2200m antenna. There is matching transformer and tap selection relays in the box at the left, a 2.2 millihenry coil/variometer in the blue drum, and a smaller version of same for occasional use on 630m in the bucket at the right.

There are no photos of the aftermath or 2200m antenna laying in the snow. I was too depressed that morning to want to document anything. I stabilized what I could and over the next several days foolishly repaired the 2200m antenna. That allowed me to continue LF operations until Spring but I knew those days were coming to an end. Assuming I was able to repair the towers and other antennas, I could never again risk a similar disaster.

The first challenge was how to finance repairs. If I chipped away at it with whatever I could manage to set aside from my income, recovery would take years. The other option was to see if I could get a loan, despite my fixed income falling below lender minimum guidelines. I was not doing so well since the loss of most radio activities. Under some gentle prompting from my health support team I decided to pursue a loan. Fate smiled upon me and I got the loan, a sum not less than a third of my annual income. It will take some time to pay that off but I was on my way to rebuilding!

It was going to be a big project for me. I do all antenna work alone. That means a lot of trips up and down the towers, as I have no one on the ground to do anything and must often make several trips up for simple tasks. There were complicating factors going into this. One was that several months earlier we lost a local ham and professional tower worker whom I had known for 40 years. He died in a fall from a tower. To be honest that really shook me up and I had some difficulty with climbing early on in this project because of it. I was at least 40 pounds overweight which compounds that darn gravity thing! But I was going to rebuild or perish in the attempt! Lastly there are always days that I am unable to work or be outside, and that has been greatly compounded by a neighborhood situation which has had several of us making complaints. It was very difficult this year to find times that I could do anything at all. I often started around 2:00 AM and finished work shortly after dawn. These same factors make it impossible to schedule work sessions even when volunteers might be available. Under current conditions I either do antenna work alone or it won’t happen at all. I don’t know how many years I will be able to continue this, so I am making the most of it while I can!

First there were preparations and getting antennas down from the more heavily damaged tower. The 2200m antenna was taken down for the final time, a very sad day since that extremely challenging band had been of great benefit to me. I miss it every day. Some trees that had rather quickly grown up along the path of my tram line were cut, and the tram line was hauled up into place.

The 2200m antenna doesn’t look like much after disassembly! Some coils of wire, three 12 foot aluminum spreaders, and some big honking insulators.
These antennas had to come down, even though things don’t look too bad in this photo. Traps on the TH11DX had broken (shattered!) plastic end caps and were weak and wobbly, some element tips were slightly bent and the boom truss was in danger of failing. Coax had issues on the 6 and 2 meter antennas, boom truss on 2m had partially failed, some 6 meter elements rotated out of plane, and the mast was severely binding in the tower top due to slight bending of both the mast and the tower top section.
Trees have been removed from the area on the left to provide space for tramming.
Ropes and cables for tramming operations. One wire rope is the tram line, the other is a backstay to prevent failure of the mast from the stress of tramming the heavy TH11DX.
The mast backstay attached to a rope and ready to be pulled up.

Special tramming operations needed to be carried out for the 6 and 2 meter antennas in order to get them past the elements of the TH11DX. It might have made more sense to remove the TH11DX first, but this was early in the season when I was very nervous climbing. To be honest, this was a mind game. I needed to see the big expanse of the TH11DX below my feet as I stood on a mast step to reach the upper antennas, or I would never get myself up there! I will argue that one should not climb if experiencing such discomfort and having to play such mind games but this was do or die for me. I was willing to take the risk of pushing myself into uncomfortable situations. In order to solve this clearance problem, the tram line was run horizontally from the mast over to the top of the other tower where it was joined to a rope running through a pulley down to a hand winch at the base of the tower. This allowed the VHF antennas to leave the tower going out horizontally, then to be lowered to the ground by letting out rope from the winch.

The 2 meter antenna suspended on the high, mainly horizontal tram line.
Tram line being lowered with the 2m antenna hanging in the middle.
The 2m antenna nearing ground level.
6m antenna out on the high tram line.
Tram line being lowered with the 6m antenna on it.
Since I was still about 40 pounds overweight at this stage, I took advantage of the tram line to bring up my bucket of tools… less gravity pulling at me than if I climbed with it attached to my climbing harness.

With the smaller antennas down it was time to tackle the TH11DX. For this, the tram was rigged in a somewhat more conventional manner, now going from the top of the mast down to a few feet above ground on the other tower. After the nearly 100 pound antenna was at ground level, I learned that I need to eat more Wheaties or something! It was a struggle to pick it up, walk over to the short Rohn 45 tower with it, and mount it at shoulder level on that tower where it would remain until everything was ready for it to go back up.

The backstay tension system. This is critical when tramming nearly 100 pounds of antenna with a tram line attached to an aluminum mast!
TH11DX suspended on the tram line. The tram line and backstay can be seen.
TH11DX about half way down the tram line.
TH11DX has nearly reached ground level.
Tram line has been slacked off by means of the comealong by which the tram is attached to the slings on the tower. That lowered the TH11DX the final bit onto saw horses.
The TH11DX moved to a temporary spot for repairs.

I was not doing so well after months of not having radio which I rely on for stress management, and really wanted to be active for sporadic E season and the Perseids meteor shower. I decided to repair and mechanically upgrade the 2m antenna and then temporarily put it on the other tower, below the 222 and 432 MHz antennas.

New, upgraded 2m boom to mast clamp. Overkill.
New, upgraded 2m truss to mast clamp. Overkill, again.
New 2m truss to boom clamp. The truss itself was upgraded from dacron rope (too stretchy!) to stainless wire rope.
Refurbished and upgraded 2m antenna.
OK, now I am happy with the alignment of elements!
2m antenna on the tram line ready to go temporarily to the northeast tower. Rather than lower HF wires out of the way, I opted to use the same high tram running between the tops of the towers, but in the reverse direction (rope, pulley and winch now on the southwest tower).
Quick and dirty rigging of antenna to tram line, but it works fine.
2m antenna on the raised tram line.
2m, 432 and 222 antennas on the northeast tower.

I caught a couple of massive E skip openings on 2 meters and did very well in the Perseids on both 2 meters and 222. I was glad I took this step of putting the 2 meter antenna up in a temporary fashion. After the Perseids it was time to remove all antennas from the northeast tower and get to work on the new VHF/UHF stack there.

The 6m antenna needed two elements rotated back into plane, new boom to mast clamp, new truss to mast clamp, new coax and a rebuild of the center of the T match.
All of the antennas down for work. 6 and 2 mounted on the utility trailer, 222 and 432 on saw horses, TH11DX on the short tower. 222 and 432 got new coax, new boom to mast, and new truss to mast.
The 2m antenna hanging on the tram line before dawn, ready to go up at first light while there is no wind. It is going up already attached to a 6 foot mast extension.
The 2m antenna is up. Photo clipped from a drone video.

I had a setback after getting 2m, 222 and 432 yagis up and mounted on the mast. While raising the mast to final position in preparation for rotator installation and adding the 6m antenna, the three coax cables got caught on the tower and damaged. I had to take all three antennas down and replace the coax a second time!

6m antenna waiting on the tram line for first light.
Sun’s up! Time to go!
VHF/UHF antennas up, northeast tower work finished (mostly).
I am happy with alignment of booms on this stack.
VHF/UHF stack from above.
VHF/UHF stack just after sunset.

Now it was time to get to work on repairing the southwest tower. I added a temporary set of guys 10 feet down from the top and lowered the regular top set. The first challenge was removing the old mast and rotator. I had to hammer things apart and beat the mast out of the Rohn 25 pointy top section with a sledge hammer! That’s a lot of fun 100 feet in the air. Replacing the tower top section required some special rigging. I had LDF5-50A, 0.84″ CATV line and rotor cable all running up the inside of that tower! There was no way I was going to dig those buried cables up and pull them out of the tower if I didn’t have to. I couldn’t replace the top section using a standard 12 foot gin pole because it lacked sufficient height to lift a tower section straight up and free of the cables. I made a long gin pole out of a 20 foot section of 2 inch 6061 schedule 80 aluminum pipe and mounted it across two tower legs with pieces of 2 inch by 2 inch by 1/4 inch thick galvanized steel angle. As with all tower section lifts, I used a counterweight on the rope below the gin pole to take most of the weight of the section. I attached a length of 1.5 inch OD 1/8″ wall aluminum tube to the braces of the tower top section to act as a lever/handle so I could push it up and off the cables. This worked out pretty well, and the new stop section was rigged the same way for going up and over the cables. In the interim since the tower was first installed I had managed to acquire a 25AG4 flat top section which is far more desirable than the pointy top. After getting the top section replaced, the permanent guys were put back in place and the temporary set removed.

The old top section rigged for removal.
The tower without a top section. Well, that looks a bit odd!
Old top section and the new one rigged for raising.
New top section in place.

I mounted a proper thrust bearing on the tower top, and put an accessory shelf at the bottom of the 25AG4 for the rotator. In between another accessory shelf was fitted with a centering bearing made of Acetal plastic. I used DX Engineering shelves and I must say they are far better than Rohn shelves! The top bearing is also a DX Engineering product. The next task was getting the new 22 foot long 4130 chromoly mast into place. Weighing 125 pounds it was going to be a challenge for me. I once again used the long gin pole to good advantage. Instead of using counterweights, I rigged a worm gear winch to haul the thing up. This was the one thing I did have help with for about 10 minutes. I hauled the mast up until the top of it was inches below the top of the tower, then had a helper run the winch while I was on the tower for the last 23 feet of lift and dropping the mast into the tower.

The mast ready to be raised.
A different view of the mast raising setup.
Tower top rigging for mast raising. From this angle, it doesn’t look like a 20 foot gin pole.
The winch used for mast raising.
Winch mounting. Well, it did work…
The mast is in!
The gin pole has been removed.

I did manage to sneak an upgrade into the rebuilding effort. I acquired an OptiBeam OB1-4030 rotatable dipole to replace my 40 and 30 meter inverted V antennas that always seemed to have me struggling to work the DX, let alone struggling for contest QSOs. I had been hearing that a dipole beats an inverted V at the same height, so I decided to try this after two failed attempts at home brewing a two band rotatable dipole in recent years. Besides, I was on a campaign to eliminate as many wire antennas hanging off the towers as possible. Skipping ahead, it turns out the improvement is nothing short of incredible! My 40 meter inverted V was at 104 feet, 30m at about 90 feet. The OB1-4030 is at 108 feet on the other tower 145 feet away. I was able to leave the old antennas in place for a while to make comparisons. The OptiBeam beat the inverted V antennas by margins ranging from 5 dB to more than 35 dB depending on the station and time of day! Every time! I have done extensive comparison using the Reverse Beacon Network. I have also experimented with calling DX stations many times with the old antenna and then the new one. Often they continue to CQ while I call time and again with the old antenna but I work them on the first or second call with the new one. I can work DX I never could before and get a much better run going in a contest. This is just amazing! Most of the time I found I no longer needed Beverages for receiving on 40 meters. The exception being during multipath conditions where the CW was difficult to copy. Then the Beverages still provide advantage.

The TH11DX needed more attention than any other antenna. The traps were taken apart, modified with additional screws to reduce wobble, shattered trap caps were replaced and covered with 3 layers of Super 88 vinyl tape, element tips were straightened, coax replaced and the ridiculously inadequate boom truss hardware was replaced with something more reasonable.

Original TH11DX truss to boom clamp. Seriously, MFJ/HyGain?
Truss to boom clamp replaced with a DX Engineering part.
The original TH11DX truss to mast clamp, which had broken after only one year of service and had to be patched up on the tower. It was nearly ready to break again. Ridiculous.
The new home made truss to mast clamp.

Six years ago I struggled to tram the TH11DX up working alone. I did it by hand, wrapping the pull rope around my waist, leaning back and walking backward for the pull. I was pleased to see that now, at the age of 58 I can still do it, and somewhat easier than the first time. That’s odd but I’m not complaining!

TH11DX on the tram line.
Another view of TH11DX on the tram line.
Closeup of rigging for TH11DX tramming.
TH11DX at the top of the tram line.
Final installation, TH11DX at 98 feet, OB1-4030 at 108 feet.

I was concerned about interaction between the TH11DX on 15 meters and the OB1-4030. I had chosen to start without a 90 degree offset to see what happened. I see no detrimental affect. The TH11DX still has a good pattern on 15 meters (and all other bands), SWR is fine, and from what I can tell it is working as well as it has all along. I got away with it!

The last of this work was completed with snow on the ground. As of December 2021 I still have some work to do on low band receive antennas which have somehow managed to develop issues during the a period of disuse. Other than that, all damage has been repaired. 160 meters through 70 cm are back up and running. The loan was a necessary evil but unfortunately it means very limited new projects for a while. During the course of this project, May through December, with great effort and force of will, I was able to lose 40 pounds. By the end of the project my comfort climbing was as good or better than it has ever been.

Why I am Falling Out of Love With VHF Contesting

I have been on VHF weak signal (meaning primarily CW and SSB operation and later digital) most of the time since 1986. I took a few years off between 2007 and 2016 but have put major effort into returning since then. During my years on VHF I have been active in most of the VHF contests.

My reasons for being involved with ham radio and the activities I seek out within the hobby may be different than most. I have always been fascinated by radio and I love DXing but this is also a much needed coping mechanism and stress relief for me. I am on many bands and modes because variety is key to getting what I seek out of this.

Several things made VHF operating and contesting different from HF. First there was propagation. On VHF there are a variety of propagation mechanisms including troposcatter, tropo, meteor scatter, aurora, sporadic E and if one has a capable station, EME. Each propagation type has its own unique characteristics and may impart a variety of effects to the signal. There is the characteristic flutter of meteor scatter, the hiss of aurora, libration fading on EME. Troposcatter signals can sound perfectly normal or they may have rapid flutter or even multipath effects. I loved hearing all the unique sounds. I felt connected to a variety of fascinating phenomena that made a signal go from here to there, learned to identify each of them and how to best exploit them. It was all part of the magic and wonder of radio.

Sometimes VHF signals are very weak. I love the challenge of digging out a weak signal by ear on CW or SSB, figuring out how to best adjust the length and timing of transmissions to get that weak one in the log.

In VHF contests one would get to know the other players. Every contest there were familiar voices on SSB and “fists” on CW. Even in the heat of battle, many would take a minute to say hi and exchange a brief remark or two. Sometimes one could get information about activity or propagation conditions that proved helpful. This was a thoroughly unique and enjoyable aspect of VHF contesting for many years.

VHF contests also provided a unique opportunity to make contacts on bands above 2 meters. Generally there is little to no regular activity up there, but many VHF contest stations have more bands and of course they wanted to work others on as many of them as possible. Generally one would work a station in 2 or 6 meters and make arrangements to QSY or “run the bands” with them. This was great fun and really made having higher bands worthwhile. If it weren’t for VHF contests I probably never would have ventured above 2 meters. Sometimes the challenge for me would be to run through several bands quickly to take advantage of a short propagation peak. I am pretty far from most of the VHF activity, so making the most of propagation peaks was important.

VHF contesting has changed a lot in the last 35 years. One of the most obvious changes is the decrease in activity. Twenty or thirty years ago I could get 70 to 90 QSOs on 2 meters in a VHF contest plus a good number on any other bands I had at the time. Except perhaps for a few hours between midnight and dawn, there were always signals to be heard on 2 meters. In contrast, for the past few years I have a more capable 2 meter station than ever before but no matter how hard I work at it, 30 QSOs on 2 meters was about all I could hope for. I was lucky if I got a dozen each on 222 and 432 MHz and whatever number on 6 meters depending on long range propagation which is far more prevalent there. There were long periods of time when no signals were to be found on 2 meters. Almost all of the big stations are gone now, so QSOs around the 500 mile mark (generally the limit for CW or SSB between well equipped stations under average band conditions at 2 meters and above) have become rare. Despite the sharp decline in activity I was still enjoying VHF contests. The longer distance contacts were all the more special and exciting since there were so few to be had.

Then came FT8. This is where my love affair with VHF contesting began to fade. It’s not that I hate FT8. I have used FT8 in previous VHF contests, day to day on VHF outside contests, and on HF. It can be a lot of fun and in some ways it is a better mode for me. Just days prior to the 2022 January VHF contest I ran piles of JA and Asia on 40 meter long and short path and had fun doing it.

The VHF contest activity that used to be on SSB and CW has been shifting more and more to FT8. Mainly this is on 6 and 2 meters while there is little to nothing going on above that. FT8 has brought many newcomers to VHF and contesting. I don’t argue that more activity is a good thing, especially in light of the decline in VHF activity over the past 20 years. Unfortunately it comes at the cost of nearly eliminating activity on traditional modes. For me this has mostly killed the uniqueness and fun of VHF contesting.

The personal connection to VHF propagation phenomena is gone. With FT8 signals are either too weak to hear, or there are several signals and it isn’t possible to hear the unique characteristics of those that are undergoing propagation curiosities. The magic and wonder of it all is gone. It isn’t possible to adapt timing, speed or length of transmissions to compensate for propagation anomalies, as all of that is locked into a fixed format. It is also common to lose contacts to QSB that I know I could have completed on SSB or CW. FT8 contacts take too much time to ride the sometimes short peaks.

For the most part the connection to people I know is gone. While it is possible to exchange a very brief remark on FT8 it is cumbersome and few do it. You need to be a lightning quick typist. It’s not the same as hearing a familiar voice or CW sending style. I find it sterile.

Making arrangements to run the bands is harder with FT8. I know some have had success with it and there is a new technique now being proposed or tried that might help somewhat. But still, I think it is much harder with FT8 than it was with SSB or CW. Also, you either need to first QSY to SSB to make arrangements, or try to run the bands on FT8. Either way takes longer than the quick, snappy band changes and QSOs one could make using traditional modes. This is not good for me. Being far away from most of the activity I often depended on running through the bands quickly to get those contacts during a short tropo peak.

I have tried to get something unique and special out of FT8 on VHF but have not succeeded. The unique feel of VHF contesting has been lost. Without that uniqueness I am losing interest. Prior to this FT8 transition, I would prioritize VHF contesting over HF contesting or DXing because it was unique and fun. Now, with what was unique and special about VHF nearly gone, I get more benefit out of chasing DX half way around the world on HF than I get from participating in a VHF contest. That is the bottom line. It may be true that at some point during a contest there is a small amount of activity on other modes, but listening to white noise for hours to catch 10 QSOs is not fun nor is it helpful to me in other ways. That is too little return on investment of my time, to say nothing of money tied up in a VHF station. After listening several times in the recent 2022 January VHF contest and hearing mainly FT8 on 6 and 2 meters and nothing on higher bands I voted with my band switch. I went to HF and worked DX half way around the world because I got more out of that than I would have working the VHF contest.

This isn’t the first time I have felt the rug had been pulled out from under me on VHF. My years of absence from VHF between 2007 and 2016 were precipitated by EME going from CW to JT65. I had spent a fortune and a great deal of time building up my EME station only to have the fun and benefits suddenly vanish. Since EME was no longer providing what I seek from the hobby I dismantled the station and sold everything off in order to build a better HF station. That was a necessary move. It took some time to regroup and begin rebuilding VHF with an emphasis on terrestrial operation and contesting. Now VHF contesting and operating in general seems forever changed by FT8.

Change is inevitable and the VHF world has moved on. Currently there is some discussion about changing VHF contest rules to encourage more SSB and CW activity. Even if changes are made, I have my doubts that it will actually revive use of those modes. There was some tinkering with EME contests after the digital revolution but did it bring back CW? For the most part, no. In the end I hope the influx of new blood brought about by digital modes proves a positive thing for ham radio, but I think we have to accept that any change which drastically alters the very nature of an activity will inevitably result in losing some, like myself, who came to and enjoyed that activity precisely because of its unique nature.

I would not presume to think of mine as a big station, though with 1500 watts on 6 and 2, 800 watts on 222 with long yagis 100 plus feet in the air it is not exactly small either. I have a high and long yagi on 432 but lack power there. If one were to consider this a big station then I guess am just the next to fall. I am not sure whether I will leave VHF altogether but one thing I do know beyond a reasonable doubt. Had I known in 2016 where we would be just five years later, I would not have made the effort to return to VHF. Building the station was a genuine hardship and involved many sacrifices. I wish I had that money back to pursue other interests where there is still something of personal value to be gained. With the changes occurring on VHF I find myself thinking about what other antennas I would have room for if I removed all of the VHF antennas from the tower. I am deeply saddened that we have come to a point where I would even consider that after all I went through to build the VHF station, but here we are.

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.