[time-nuts] (no subject)

wa1zms at att.net wa1zms at att.net
Mon Apr 14 10:48:17 EDT 2008


Although you are likely OK being at VHF, please keep in mind that some
of the low-freq "clock" type oscillators have poor phase noise when
it comes to trying to copy signals like CW.

A good easy test is to listen to one of the oscillators on a good
general coverage RX and see how "good" the CW note sounds. If you're
happy with it, then its use as a LO for a transverter is likely OK.

Also remember that modes like PSK31, WSJT, etc. will want slightly better
LO phase noise to function well.

But the CW listening test is a simple easy place to start.

Brian, WA1ZMS/4

 -------------- Original message from "David Hilton-Jones" <David.Hilton-Jones at clneuro.ox.ac.uk>: --------------

> I want to generate sine wave signals at 42MHz and 116MHz for use with VHF 
> transverters. A simple tcxo isn't stable enough. I'm looking for simple/cheap 
> solutions and I'd appreciate any comments.
> 1) I have a stable reference at 10MHz available
> 2) Reflock is overkill
> 3) I guess a G8ACE type ocxo would do for 116MHz.
> 4) I read with interest about FlashCrystal units, but they now seem unavailable.
> 5) On e-bay international I see McCoy/Vectron ocxo at 48.xxxxMHz (can't remember 
> exact frequency) - that might do for my 42MHz requirement , with some mods to 
> the rest of the transverter. Any UK source?
> 6) I don't know much about DDS systems.
> Any comments much appreciated.
> David
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