Thread: Franklin VFO ?
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Old 16th May 2019, 10:55 pm   #38
Radio Wrangler
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Default Re: Franklin VFO ?

Quote:
Originally Posted by Granitehill View Post
The major unknown would be the noise level. Since the oscillator is running at
low level, would'nt this imply a highish close-in noise spectrum ?
Has anyone got any ideas on this, rather than the more usual Clapp, Seiler, Vackar etc ?
Well, the original post was a question about thoughts on noise content.

You can indeed get away with significant phase noise sidebands on an amateur HF transmitter. Probably no-one will notice.

Try the same dirty oscillator in a receiver, and through the wonder of reciprocal mixing, all the signals in the band will appear to have the same relative level of noise sidebands and this will be at a level that will limit your ability to read small signals close to large ones. Not too bad now unless you're playing in DX pile-ups, but it used to be hellish with the high power broadcasters next door to the 40m band.

David
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