Monday, 8 July 2013

Ominous Whispers

This afternoons construction session started badly. In trying to remove the key component I desperately need from the old modem it was attached to, I broke it. So, no audio isolation yet. As if anyone but me cares. Occasionally, I wonder whether or not anyone is actually reading all this wittering I post on here, apart from the odd unfortunate soul directed here to look at a picture, from some other forum or group. Not that it matters even remotely, I write this stuff just to have a good moan and put down my thoughts on the projects im working on.

Ive managed to separate all the  transistors from all what I aquired yesterday, all that remains is to actually sort through them and put them away in the appropriate containers. At the moment they are cluttering up my antistatic mat somewhat


Despite that, I managed finally to get somewhere with the 10m WSPR beacon transceiver. Now having the right parts, including a few from yesterdays haul, ive managed to complete the build of the 14MHz Local Oscillator. Surprisingly, theres a lot going on on that little Colpitts circuit! With the two output capacitors in place, plus the bypass and decoupling capacitors, its rather a tight little circuit. Powered up, working first time, and showing 14.055MHz, a little tweek of the trimmer capacitor and its now dead on 14.0623Mhz as required for doubling to 10m.

The two coupling capacitors can be seen, the one crossing over the black line will feed the Polyakov mixer in the receive chain. The black line separates the transmit chain (upper board) from the receive chain (lower board). All I need to do now is decide whether to build the transmit or receive chains next!

Apart from a few more bench tests on the receive converter, measuring FM SINAD etc, ive done nothing further on the 4m transverter. I might tomorrow rig up an antenna and let it listen on the band for a while, see if I can find anything off-air, whilst I get on with some of the jobs Julie has left for me nearby in the garden.

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