I thought my 200mW Madagascar Mighty Mite (MMM) would benefit from some sort of afterburner, so I dusted off a project shelved in 2011: the Texas Topper amplifier. I had built based on a design by Chuck Carpenter and kitted by Rex Harper. I ran into a couple problems back then, including some difficulty getting the bias right on the mosfet at the heart of the amplifier. In another brilliant move, I managed to burn out said mosfet by grounding it while trying to get it and its heat sink to fit into a metal box.
Over the last few years, there have been a spate of postings from homebrewers taking inspiration from the Soldersmoke podcast to whip up various incarnations of the Michigan Mighty Mite, a very simple rock-bound QRPp transmitter. I’m a little late to the party, but here’s my story.
I was in the Washington, DC area for a day, and couldn’t resist activating Sugarloaf Mountain — it is just too convenient a SOTA peak to ignore. Everytime I’m in the area, I think about going up it, but often summer weather has foiled those plans. Not this time, though. It was a sunny day for my 45 minute drive out from Bethesda, MD to the trailhead.
This storm is already intense and predicted to hit the north-east side of the island tomorrow morning with hurricane force. For the last three years, we have been lucky with storms tracking to one side or the other of the QTH, but the track for this one cuts straight down the center of the island and should pass near the capital city, Antananarivo. The prediction has been consistent and is now close enough to be sure that we will experience some rough weather in the next few days.
To that end, for the first time, I have lowered the hex beam antenna. I collapsed down the telescoping sections of the heavy duty 10m spiderbeam mast and threw some additional guy lines over the central plate to which the arms attach. The wooden support beam goes two meters into the ground and is surrounded by buried concrete, so I am not worried about the base, but I do expect the fiberglass arms to be battered about. I considered dismounting the whole antenna, but that would have required more manpower than I have readily available, so it will have to ride out the storm.
Conditions over the previous week have been good, so I decided to put in an effort on the ARRL INT DX CW contest this weekend. I knew from experience that I would not be able to work around the clock since the US and Canada are not typically in range in the morning, so I anticipated being able to get some sleep from about 4 am through early afternoon, which was fine with me. Reviewing recent logs and VOACAP predictions, I mapped out propagation paths and figured where I would point the hexbeam, and more or less stuck to that plan. Over the course of the contest, I put in about 23 hours in the chair.
I was effectively limited to three bands: 15m, 20m, and 40m. Ten was almost uniformly dead, and my 40m loop is very inefficient on 80m. Bands faded in and out more or less as predicted including some good spans of working the west coast on long path in the afternoons.
Lately, I’ve been hearing a good deal of voice in the CW portion of 20m and 40m. I’ve already made some mental adjustment to being in Region 1, where the band plan allows for voice operation below 7.1Mhz on 40m, and even on the 30m band. However, what I’m talking about is very near the bottom edge of the bands…and sometimes slightly below. I have to assume the signal source is close, but I can’t spin my delta loop to get any hint of direction.
And then tonight, I had an odd one — in the SSB portion of 20m, but on lower side band (not a matter of DSB, I checked). Here’s a bit of captured audio from 14236.5khz at 15:38z 19DEC (quality’s not great because I just recorded off my headphones with my cell phone…)
In all cases, these signals sound like a bunch of buddies talking informally, without callsigns or any formal procedure. I have to assume it is unlicensed operation, most likely in an area where there isn’t really much provision for enforcement.
Anybody recognize the language in the audio clip? I’d love to know what their chatting about.
Conditions were up and down over the weekend, but not so bad as I had expected. At times, I could hear, but not be heard with 100W, so again a bit more power would have been helpful. I was probably on the air for about 24 hours out of the contest period, but did use some spotting assistance, so I won’t enter in the classic category this year. Tactically, that puts me at a disadvantage, but since this was a casual operation, I’m not too concerned about score.
I am aware of one other station from Zone 39 operating in the context, FR4NT. If cluster spots are any indication, he did a great job, with long runs particularly into Europe.
I ended up working 94 DXCC entities, some of them new to me. Through the magic of an excel spreadsheet, here they are: Aland Islands, Antigua & Barbuda, Argentina, Aruba, Asiatic Russia, Australia, Austria, Bahrain, Belarus, Belgium, Bonaire, Bosnia-Herzegovina, Brazil, Bulgaria, Canada, Canary Is., Cape Verde, China, Corsica, Crete, Croatia, Cyprus, Czech Republic, Denmark, East Malaysia, England, Estonia, Ethiopia, European Russia, Federal Republic of Germany, Finland, France, Greece, Guam, Hungary, India, Indonesia, Ireland, Isle of Man, Israel, Italy, Japan, Kaliningrad, Kazakhstan, Kenya, Kuwait, Latvia, Lebanon, Lesotho, Lithuania, Luxembourg, Macedonia, Madeira Is., Malta, Martinique, Mexico, Micronesia, Montenegro, Morocco, Namibia, Netherlands, Norway, Oman, Panama, Poland, Portugal, Puerto Rico, Qatar, Reunion Island, Romania, Sardinia, Saudi Arabia, Scotland, Senegal, Serbia, Slovak Republic, Slovenia, South Africa, Spain, Sweden, Switzerland, Tanzania, Thailand, Tunisia, Turkey, Ukraine, United Arab Emirates, Uruguay, US Virgin Islands, USA, Wales, West Malaysia, and Zimbabwe.
I should be able to put CQ zone 39 back on the air this weekend, at least for part of the CQ WW SSB contest. I’ve had a ton of travel and a few other projects over the last few months, and have been off the air except for portable operations outside Madagascar. Timing is good this weekend, though, for me to get on the air as 5R8SV from the house in Antananarivo.
I think the ionosphere may have taken my inactivity as a personal affront, because it seems to have tanked. Not having really paid much attention to propagation conditions for a couple months, I am stunned by how far the averaged sunspot number has plummeted (to 12!).
I just ran some simulations for the upcoming weekend, and 100W with a hexbeam may be marginal for Europe, much less the US. I hope some of the higher bands will pop open here and there, but I am not expecting much.
I just looked at conditions over on solarham and hope that the choppiness of the last few days will settle down for the weekend. We’ll see!
I should be in Madagascar in a few weeks, but I’m not sure whether I’ll be at home in Antananarivo or in the northern part of the country. There’s a chance I’ll be in Nosy Be, if so, I might be operating that contest QRP portable. While lower power might be a challenge under these conditions, Nosy Be is on NW corner of the island, and surrounded by salt water, so maybe worth a shot.
I make small status updates every month on the 5R8SV page on QRZ.com, but after a while, the page becomes too long and the info grows stale. I would hate to lose this record, though, because it’s a nice account of what I’ve been up to, so I am pasting the last year’s worth of comments below and cleaning up the QRZ page. Continue reading “The last year of QRZ updates”
The rainy season runs from about November and sometime up to March, with peak cyclone activity at the height of summer, January and February. As a preventative measure, my next door neighbor trimmed one of the trees along our property line. I had some ropes in that tree to support a G5RV and when he gave me the heads up that crews would be whacking away at limbs, I thought it best to bring down the antenna. The G5RV never really hung high enough to work well and it stretched over the house, which may have added to noise, so I didn’t mind taking it down. Last week, I put up a new full wavelength 40m delta loop as a replacement.
I went with the delta loop because there is one large pine tree at the edge of the property and I was able to shoot a line over it with a wrist rocket. The lower corners are supported with guy lines from a telephone pole and another tree to each side of my house. The antenna is fed at the middle of the base, which is just at the edge of my roof, which makes it convenient to access. I had brought back a 50m roll of heavy duty green wire from Sotabeams in the UK. I have to remark that working with this very compliant wire was a pleasure after having made wire from household wire that loves to coil in the past.
By virtue of the position of supports, the antenna slopes from bottom to top towards the south, a bit more vertical than horizontal. Since I am feeding it from the bottom, the antenna polarization should be horizontal, but I believe that the sloping should add some directivity towards the North. I had considered feeding it up one side and using a quarter-wave of 75 ohm coax to transform the expected 100-ohm feed point impedance, but it would have been awkward to support a feedpoint at that position given what I had to work with.
I initially cut the antenna to a literal full wavelength, 299.8/7.1 * 1.05, where 1.05 was the fudge factor supplied in the ARRL antenna handbook. Initially, the resonant point was 6.9 Mhz, so I shortened the antenna in a few iterations, arriving at the intended 7.1 Mhz, where there was no reactive component and the resistive component was about 65 ohms — close enough to 50 for me to be happy to feed directly with 9913F7 coax and not worry about vSWR.
From the shack, the antenna works great with no tuner across 40m, but I don’t have a lot of experience at this point with regard to how the antenna performs. It is much louder on 40m than the hex beam, but most of the time that loudness is merely more noise thanks to the environment around the station.