We have kind of half a holiday today -- I have the day off, but the kids went to school. I made use of the additional shack time to test the feasibility Farhan-izing my old, not-so-beloved Heathkit SG-6 signal generator. I did a quick Manhattan build of the oscillator section from Farhan's sig generator (link in yesterday's post). Using an idea from an old 73 Magazine article on a similar project (thanks Clint!), I smashed the tube (appropriate, don't you think?) and connected (using the glass stump!) Farhan's oscillator directly to the pins that lead to the switchable coils and the variable cap of the SG-6. I just wanted to see if it would oscillate, and see if there was a big change in SG-6 dial calibration.
Wow, it worked great! It oscillates very nicely on all but the upper frequency band setting (20-50 MHz). I feel confident that I'll get it to oscillate at least up to 30 MHz. Next I'll build Farhan's buffer and amplifier stages. The SG-6 had a switchable attenuator -- I want to include that feature in the solid state version. I'll have to give some thought to the audio modulation feature (nice for aligning AM receivers).
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I love your blog, but found the words "I smashed the tube" disturbing. I lost my valve (tube) collection years ago and am slowly rebuilding it. To hear of wanton destruction just does not seem right.
ReplyDeleteNick. ex-G7HEX