SOTA: Cabeza Arcon (EA4/MD-053)

A view from the peak featuring my unusual choice of footwear for a mountain hike.

For my last summit activation in Spain on this trip, I had two enticing options: first, I could aim for some of the ten-point peaks that lie along ridges or I could activate a peak for the first time. There are two good prospects in the first category: the peaks of Valdemartin (EA4/MD-004), Cabezas de Hierro (EA4/MD-002), and the Asómate de Hoyos (EA4/MD-006) all along one trail, and it looks like that trailhead could be reached by taking the ski lift up from the Estacion de Esqui de Valdesqui (presuming it runs in the summer). Similarly, Najarra (EA4/MD-013) and Bailanderos (EA4/MD-011) lie along a trail, which could probably be accessed by parking at 40.82797N x 3.83015W.  In fact, it might be easier to reach Asómate de Hoyos by continuing west from Bailandreos rather than east from Cabezas de Hierro.

Predictably, I went for the first-time activation of EA4/MD-053, Cabeza Arcon. This is in no way a technically difficult peak, so I assume that it was recently added to the list of summits.

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SOTA: Nevero (EA1/SG-003)

Looking at SOTAmaps, several associations overlap to the north of Madrid. I realized that without really going too far out of my way, I could visit a ten point peak in the EA1/SG association, which would put me over the top for gold level on the SOTA mountain explorer award. I’m not that much into awards, but why not? Having flown 8000 km to get here, another 20 km on the road is a drop in the bucket.

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SOTA: Cerro del Castillo (EA4/MD-052)

Recently, I attended a conference in Madrid and had another one scheduled a week later in Vienna. Instead of flying back to Madagascar between them (insane), I decided to take a few days leave in Spain (sane and fun).

There are plenty of mountains within an hour’s drive of Madrid, and many of these peaks are found in national parks. Just to the other side of that central range is the historic city of Segovia, so I booked a hotel a few kilometers outside Segovia.

Between Madrid and the hotel, I identified Cerro del Castillo (EA4/MD-052) as a target of convenience. It is a four-point summit in a region full of ten point summits, but I thought that I could do it in what remained of the afternoon after checking out of the hotel in Madrid and picking up a rental car at the airport.

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suDDSon Receiver

Components strung together somwhat chaotically with wire on my bench
20 meter band pass filter, Sudden Receiver, VFO-in-a-box, HiPerMite audio filter, PC speakers.

My longish term goal is to build the LBS transceiver described by N6QW and KK6FUT (who I see is now AI6YR) and I am methodically working my way through that project.

However, I am not above taking a shortcut for instant gratification along the way. Remember the 80-meter Sudden Receiver variant I built a few weeks ago? Well, not much use for it in my current location. It occurred to me that I could gut the 80-meter parts of it and use the NE602/LM386 core as the rest of a very minimal direct conversion receiver for a more useful band, say 20-meters. So that’s what I did and long story short, it worked.

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Madagascar Mighty Mite Experiments

On one hand, it probably doesn’t make too much sense to try to refine the MMM (the construction of which was described in an earlier post): it’s more an oscillator demo than a building block of any more complex radio, but there are a couple variables that I thought would be fun to explore: choice of transistor, supply voltage and emitter resistor value. Tables and pretty x-y graphs follow.

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VWS Field Day 2017

Photo of VWS field day site including multiple operating positions.
Antennas set up at VWS Field Day 2017: the mobile-mounted VHF station (left) and multiband hexbeam HF station (right).

Over the summer, I managed to get back to Virginia just in time for ARRL Field Day with the Vienna Wireless Society. The trip itself wore me down – I had just spent a few weeks in the US, returned to Madagacar for a week (just long enough to get back on local time), and then back to the US for Field Day. However, because my brain was still on East Africa Time, I was unusually perky for the midnight to 8 am shift on 80m.

Our best year yet

Our numbers were just compiled and reviewed at the last club meeting; a really polished analysis is available online.  This year we did much better than last year; this year’s score of 12,302 points blew past the club’s 2009 all time record of 10,958 as a class 4A station. We essentially doubled the QSO count from the prior year, with all four stations pulling hard through the night to keep up the rate.

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The MMMM Receiver

Prototype construction of the MMMM receiver. The, um, interesting position of the coils is explained below.

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).

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The Topper Amplifier Revisited

The amplifier built manhattan island style on a copper PCB 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.

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The Madagascar Mighty Mite

Finished mighty mite on copper board
The completed (yet unboxed) MMM.

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.

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