[hpsdr] 122.88MHz Oscillator

[Dick Faust]

The current discussion of the oscillator  reminded me of a similar 
discussion about a month age that also included comments about 
transverters and using the phase locked 122.88MHz as the local 
oscillator for a 2M transverter with a 21.12MHz IF.  This puts the image 
in the middle of the FM band, but should be a reasonable task to filter.

My question is what level of 122.88MHz drive is available from the 
various boards ?
Mercury and Penny/Pennylane appear to have a buffered signal available 
on their respective J1's.  The manuals are specifically vague with 
regard to J1 and nothing is specified.   The schematics appear to have 
all of the info except for easily finding out where else the "125MHz'' 
line connects.

Hermes is less clear.  The oscillator is apparent, but finding out if 
there is any buffered line is not obvious.  It would be nice to be able 
to get the signal from Hermes.

Another approach is to use a separate osc like an ICS501 with a 
19.66080MHz crystal [x6.25 multiplier], but I wonder if this would cause 
interference in addition to the loss of accuracy and coherency.

I am guessing that it would not be feasible to phase lock another 
external 122.88 clock with either a Hermes or Atlas bus board.

Has anyone else done something like this or thinking about this approach 
?  Can anyone enlighten the group [& me] on the limitations of using the 
122.88 signal from any of the boards ?

Thanks

Dick Faust K9IVB