(tr)uSDX working! – first day tests!

Having messed up slightly by installing a turned pin SIL socket on one PCB and then realising I didnt have a turned pin SIL header the trUSDX project has been on hold whilst I waited for some of the correct header pins to arrive. The header pins actually arrived a couple of days ago but I have been too busy to return to playing with the radio.

Saturday morning came and at last I have had the time to complete the build (well, apart from putting it into a nice enclosure – that will come later). So, a strong cup of cofffee with BBC Radio 4 in the background, and I wound the last couple of toroids (actually it was the FT37 transformers which I had left as a ‘treat’ until the end!) and then fitted the RF amplifier devices (3 x BS170 FETs).

First tests to check the receiver (HF wire antennas) and I was pleasd to find that the bands were alive with strong CW and SSB signals from 80m through to 20m (helped of course, as is customary on a weekend, with lots of Contest QSOs). So, I made a quick YouTube video of the radio on receive (see YouTube clip below). A couple of CW calls on 20m were quickly answered (HA, HB9 and IT9) and some decent reports on the Reverse Beacon including VE2WU in Quebec, Canda) I’ve also shown below the results of later CW tests on 40m and 80m

Next, it was time to wire up a microphone (I am not using the onboard electret – I used a spare (and larger) module left-over from an old BiTX project. A quick tune through 40m looked promising with lots of PA stations working away in the PA contest. I promptly worked over 10 stations and made a clip of SSB QSO #1 on this radio with PI4CC, again see below.

So what next? I need to wire up a proper microphone and then fit the radio into an enclosure. As far the the enclosure goes I am not inclined to put it in one of the 3D-printed organge cases (ie. the DL2MAN original), time to have another look in the junk box I think!

I’ll probably have a go on FT8 and RTTY also because, er … why not!

Running at just 5V (0.45W out) on 20m.

CW at 4W on 40m
CW at 80m

and later in the evening…

SSB Audio quality



and testing transmit, 40m QSO with PI4CC

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