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es Bernd 2025-12-30 23:19:40 No. 2
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Ham-Radio-Bernd is currently building a small radio transceiver. It's from a kit (QRPLabs QMX+), so I didn't design it myself, but I plan to make some changes once it's fully up and working. Especially the output power (3-5 Watts depending on the frequency) is too low for my taste, and I think I already know what I can do about it. I don't really plan to use this device a lot, I already have a commercial transceiver that puts out 100 Watts and weighs less than 2 kilos, which is light enough to just put it in a backpack. But part of the Ham Spirit is to try to understand as much as possible about the technology you're using and come up with clever solutions. Building this kit already taught me a lot about real-world high-frequency electronics, modulation etc. that I only knew in theory or didn't know at all. What I don't really like about it is that about 70% of the build time goes into winding lots of turns on 18 very tiny ferrite cores, each of them about a centimeter in size. It feels like working in a Chinese jewelry sweat shop. But that's all part of the experience.
es Bernd 2026-01-02 00:00:51 No. 13
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I finished building the transceiver yesterday. It took around 15 hours in total, pretty much just because of the ferrite coils. The rest was completed in two hours at most. Optical and electrical inspection (digital voltmeter) identified a couple of unreliable solder joints that I then fixed without too many issues. The device worked on the first try. I went through all the built-in self tests and measurements, everything works but some things have to be tuned. The biggest issue being that it puts out only 3 Watts on some frequencies instead of something around 5 Watts. I tried to make some radio connections to fellow hams, but couldn't make a single contact. 5 watts are very, very little, I will have to try from a different location and with a better antenna.
de Bernd 2026-01-02 01:22:46 No. 14
What can you do with it? Only AM/SSB voice or can it some cool things like digimodes? And on what bands?
es Bernd 2026-01-02 21:04:05 No. 15
>>14 It does CW, SSB and Digimodes on all amateur bands between 160 and 6 meters, plus the 11m CB band. SSB was only recently added in the firmware, from the start it could only CW and Digimodes. It has a built-in automatic WSPR/AFSK/CW beacon mode with an optional GPS module that is used for time synchronization and to select the correct locator. The Digi mode is a bit special. It samples the audio input, identifies the currently used audio frequency, sets the oscillator to the effective center frequency of that sub-signal and sends out a pure sine wave without any modulation. This works only for AFSK modes like WSPR and FT4/FT8, but those are the predominant modes nowadays anyways and bypassing the whole audio path makes for a much better signal. Another novelty is that it uses a class E amplifier in combination with polar modulation. This means it can still do SSB (which wouldn't be possible with classic modulation on a class E amplifier) while consuming much less power than other SSB-capable devices.