I was based in Madagascar from 2014 to 2018 and made a habit of posting short status updates on my QRZ page. To keep the page to reasonable length, I would occasionally move those entries over to this blog when they became dated. So, here is the last installment of updates from 5R8SV. The previous ones are also posted on the blog (most recent and earlier and even earlier and the first ones). The station has been QRT since the end of July, 2018. I donated some of the station equipment to local hams and makers, but everything else was either shipped back to the US or forward to my next assignment in Cyprus. I still have the callsign for another year, but doubt I will have a chance to use it.Continue reading “Final update from 5R8SV”
Operations from Madagascar
Focus on 30m
Well, that went pretty well — about two weeks of after-work operation on 17m FT8 with a low-hanging end-fed dipole and 25W, and I pushed my DXCC count on 17m over 100. Thanks to 9G5AR from Ghana for putting it over the top.
Postcard from the ISS
This weekend, Russian-ARISS transmitted SSTV images of satellites hand-launched from the ISS. They used a high-resolution mode, PD-120 transmitted FM on 145.800.
I was set up for FT8, but switched over for one pass and captured this image. My process for decoding was suboptimal — I recorded using audacity on my Mac and then later played the audio back to a PC set up with MMSSTV. I didn’t have an attenuator on hand, so of course the sound level was high for the PC input, but was able to drop the gain a bit in audacity. Maybe I traded off a little image quality, but it worked.
This was a low pass (max elevation of about 12.5 degrees) on a side where I have some obstructions — those horizontal lines are probably tall trees — so probably not the best image I could have captured, but I was just curious if it would work at all.
I’ll be squeezing out what QSOs I can on 17m FT8 through the end of July 4th and will then swap in a 30m element on the antenna for the next couple weeks.
5R8SV Satellite Ops
After I took the hexbeam down, sanded it, painted it and packed it away, I still had a G450 rotor on my hands, so I thought I would try my hand at satellite operation. Over last weekend, I literally lashed together a satellite station — the rotor platform is held to the roof with taut line hitches.
Our house isn’t ideally situated for satellite operation — particularly to the south where some tall pine trees blot out the sky, but in the other directions, the antenna can see down to about ten or fifteen degrees above the horizon.
I arrived back in Madagascar late in the evening last week after a brief vacation in Réunion. The next morning, I fired up the rig to see what was going on in the CQ WW WPX SSB contest and rotated the hexbeam towards Japan. The rotor control showed movement through about the first ten degrees, and then it froze. I backed off, tried jiggering it back and forth a bit, thinking that perhaps it was just sticking, but gave up after a few seconds because I didn’t want to strain the motor. I walked out back…
… And it was clear why the antenna wasn’t rotating, about a meter and half below the base of the hex beam, the mast had a kink of about 20 degrees, and the hexbeam was lopsided, brushing against a nearby tree. After surviving four cyclone seasons, it appears that the last one of this season, Eliakim, took its toll.
The MMMM Receiver
The 80m Madagascar Mighty Mite was suffering from “a tree falls in the forest but nobody hears it” syndrome. Eighty meters is a tall ask for Madagascar — there aren’t that many hams in the coverage area, and given local noise, I doubt any of them can hear well on 80m. It would be a long wait for a signal report about the on air performance of the MMM. Clearly, the thing to do was to create a mate for the MMM, the Madagascar Mighty Mite Mate (MMMM).
In keeping with the philosophy of back-to-basics rockbound simplicity, I decided to build an 80m version of the Sudden Receiver originally described by George Dobbs in SPRAT, and reprinted in 73 (October 1991, page 8, available online thanks to the Internet Archive).
The Topper Amplifier Revisited
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.
The Madagascar Mighty Mite
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.
Tropical Cyclone Enawo
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.