Resurrecting an oldie a PYE Cambridge
Resurrecting an oldie a PYE Cambridge
by jomac Sat Sep 28, 2013 8:38 pm
I recently acquired a very old PYE Cambridge in remarkably good condition which had a couple of crystals on the 4Mtr band. Now i hate wasting stuff and this old set (now 50 years old) wasnt worth recycling for the bits due to size etc. But something made me want to give the girl a new lease of life.
The set had been nicely converted from AM to NBFM and could be switched between both modes and a narrow filter fitted.
I would like to synthesize this set to cover the full 70.000 to 70.500 Mhz band. I have built a few of Harry's "Improved CMOS RF Synthesizer" and very happy with the results this gives, this is the synth i want to use, because i have even interfaced one with a PIC micro.
The question is, which is the best way to mix the output from the synth? If i go to far back into the multiplier chain, i probably wont get the right frequency steps after multiplication.
As i want to use parts im used to, what would be the best approach to mixing the output from the synth, to give a final 70 to 70.5 Mhz? The original CMOS synth has an output of 50Khz to 2Mhz (?) The two mixers ive used in the past have been the NE602/612 and the Minicircuits mixers.
Really the question area's are what frequencies are the best to mix at, and the best approach to this problem?
The set had been nicely converted from AM to NBFM and could be switched between both modes and a narrow filter fitted.
I would like to synthesize this set to cover the full 70.000 to 70.500 Mhz band. I have built a few of Harry's "Improved CMOS RF Synthesizer" and very happy with the results this gives, this is the synth i want to use, because i have even interfaced one with a PIC micro.
The question is, which is the best way to mix the output from the synth? If i go to far back into the multiplier chain, i probably wont get the right frequency steps after multiplication.
As i want to use parts im used to, what would be the best approach to mixing the output from the synth, to give a final 70 to 70.5 Mhz? The original CMOS synth has an output of 50Khz to 2Mhz (?) The two mixers ive used in the past have been the NE602/612 and the Minicircuits mixers.
Really the question area's are what frequencies are the best to mix at, and the best approach to this problem?
jomac- Posts : 11
Join date : 2013-08-26
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