Re: Input Needed for RadCom Column


Andy G4JNT
 

I once generated WSPR using a carefully adjusted varicap across a crystal, then drove it with a simple two-bit A/D (two resistors).   JT4x would work just as well (there's not a lot of difference between it and WSPR)

But still needed a PIC to generate the timing and symbols; you can't get away from having to use some sort of controller.   Unless...   You coded it onto a wheel with an opto coupler (dual channel of course for four levels)    But you still need PC software to calculate the symbol pattern and GPS or accurate clock time info.
  


On Wed, 22 Jan 2020 at 15:29, Adrian G4UVZ via Groups.Io <adrianwhatmore248=btinternet.com@groups.io> wrote:
A question rather than an answer!  A couple of years ago, as beacon keeper for GB3KBQ I wanted to bring the beacon into the 21st century. Whilst the existing system is very frequency stable using 35 year old  a Pye HS400  https://uhf-satcom.com/misc/hs400-reference-oscillator  and multiplying it's 27MHz o/p up to 10368.87 MHz . The FSK keying is very agricultural using a reed relay to offset the 5MHz TCXO. Having seen the benefits of JT4G modulation system in tests with Neil G4DBN, I was hoping that I might be able to get KBQ emitting these tones. Sadly I drew a blank on a suitable design. The beacon requires around 0dBm at 10GHz ..or 108MHz at a similar level.(Tone spacing woud have to be divided by 96)

For avoidance of any doubt ..whilst I can build hardware, measure rf levels and frequency accurately. Programming eproms, flash memory, PICs, programmable arrays etc is beyond my ability!

Perhaps an article addressing the above would be of interest to other beacon keepers?

Adrian  G4UVZ

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