[hpsdr] Penelope locked to ext 10 MHz Atlas bus ref

[Joe Martin K5SO]

Phil VK6APH and All,

Rather than reporting a problem to you, I thought you might like to  
hear of a small success out here in the field for a change, hihi.  I'm  
pleased to be able to report that I had no problem at all in locking  
my Penelope TX to an external 10 MHz source (Rb vapor frequency  
standard) via the Atlas board using a simple conditioning  circuit  
consisting of a 5V Zener clipping diode on the input of a TTL inverter  
(actually, a 7400 NAND with inputs tied together) with a resistor  
divider on the output to lower the 5V TTL level to 3V max level to pin  
C16 on the Atlas board bus.  It seems to work great; after selecting  
Atlas as the 10 MHz source on the Setup/General/HPSDR tab in PowerSDR,  
of course.

Best of luck to you in getting Mercury closer to beta testing pretty  
soon!!  I'm sure excited about that prospect!

73,  Joe K5SO