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Andrew2 · 22nd Jul 2019, 8:30 am

I struggled with this when I built my homebrew 160m transceiver. The design is a straightforward single superhet with an IF of 455 kHz, so obviously it needs carrier oscillators for generating the AM and SSB signals. The one on 455 kHz for AM was fine, just a cheap Murata 455 ceramic filter in a Colpitts osc, but the one for SSB had to be pulled down to 453.5 kHz. I went through many ceramic filters before I found one that would pull far enough in the right direction and start reliably. A lot of 'optimising' of the feedback capacitors was called for.
However, it all worked fine in the end and the rig is still in use.

22nd Jul 2019, 8:30 am	#13
Andrew2 Nonode Join Date: Mar 2010 Location: Dukinfield, Cheshire, UK. Posts: 2,038	Re: Use of a Ceramic Resonator in a BFO I struggled with this when I built my homebrew 160m transceiver. The design is a straightforward single superhet with an IF of 455 kHz, so obviously it needs carrier oscillators for generating the AM and SSB signals. The one on 455 kHz for AM was fine, just a cheap Murata 455 ceramic filter in a Colpitts osc, but the one for SSB had to be pulled down to 453.5 kHz. I went through many ceramic filters before I found one that would pull far enough in the right direction and start reliably. A lot of 'optimising' of the feedback capacitors was called for. However, it all worked fine in the end and the rig is still in use. __________________ Andy G1HBE.