[R-390] COSMOS PTO EP ADJUSTMENT

[Bernie Doran]

If one thinks they have some need to read frequency that close, would it not 
be simpler to simply buy a POS jap rx and either use that, or zero beat what 
ever it is you are listening to? Or better yet, buy a SDR-IQ and tell 
everyone that you are looking at the band for signals.   Bernie W8RPW
----- Original Message ----- 
From: <DJED1 at aol.com>
To: <n4buq at knology.net>; <r-390 at mailman.qth.net>
Sent: Wednesday, April 21, 2010 5:45 PM
Subject: Re: [R-390] COSMOS PTO EP ADJUSTMENT


>I thought about a synthesized PTO replacement, although I'm really an RF
> engineer by trade.  I found two problems I couldn't solve- maybe someone
> else can help out.  First, you need better than 100 Hz resolution, which 
> means
> either an encoder with better than 1000 bits/rotation (very expensive), or
> a gear driven encoder.  You definitely need two encoders- one to count in
> Hz and one to count in 100 KHz.  Finally, if you solve all that, you need
> to retain the settings in memory on power down so you don't lose the
> synchronization between the - and the rest of the RF module.  Probably a 
> simple
> micro could do that.
> I thought it would be really neat to have an absolutely linear PTO 
> accurate
> to 100 Hz over the whole range, but it's beyond me.  If anyone wants to
> help out, just jump in.
> Ed  W2EMN
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