UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

ppppenguin · 16th Sep 2005, 12:21 pm

My design, AKA Telebox, is almost identical to David Looser's. I would not expect significant performance differences between them. The only critical thing I found was that the crystals tended to osciallate on their fundamantal instead of 3rd overtone unless damped a bit.

Darius's design looks good - he has the RF knowledge and test gear - and I would respect Peter Scott's opinion too.

David Robinson's design using a Motorola(?) chip is possibly the most interesting of all as it is inherently programmable to many channels and does not need a special crystal at all.

The direct digital synthesis approach that Darryl (the Aurora man) and I discussed both on and off forum is technically interesting but I would not recommend it unless you really know what you are doing. It wouldn't be cheap for a 1 off.

16th Sep 2005, 12:21 pm	#4
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: VHF modulators My design, AKA Telebox, is almost identical to David Looser's. I would not expect significant performance differences between them. The only critical thing I found was that the crystals tended to osciallate on their fundamantal instead of 3rd overtone unless damped a bit. Darius's design looks good - he has the RF knowledge and test gear - and I would respect Peter Scott's opinion too. David Robinson's design using a Motorola(?) chip is possibly the most interesting of all as it is inherently programmable to many channels and does not need a special crystal at all. The direct digital synthesis approach that Darryl (the Aurora man) and I discussed both on and off forum is technically interesting but I would not recommend it unless you really know what you are doing. It wouldn't be cheap for a 1 off.