[R-390] R-390A frequency drift stability specs

[Stan Gammons]

On 1/23/2018 7:17 PM, Larry H wrote:
> Bob, you are right about the crystals being cut for the temp of the ovens they are in to get minimum drift, and the switch on the back turns off both the VFO oven and the 2nd crystal osc oven.  I've thought about disconnecting the VFO oven wiring and running with just the 2nd crystal osc oven on, but my stability seems good enough with it off (although I have not actually measured it).  Perhaps some day when I open up my VFO again, I will cut the wire.
> Regards, Larry

I tried measuring the stability of my R-390A using WWV and the FreqCal 
feature in WSJT-X.  My signal to noise ratio a good bit less than 20, so 
the results aren't reliable.  I have used my R-390A for FT8 and it 
worked.  I tried attaching a capture of the waterfall to an earlier 
message, but the image got tossed. Signals in the waterfall were 
straight and not leaning to one side or the other which would indicate 
drift.  I haven't tried the much longer duration JT65 and JT9 signals 
though.  I realize the R-390A isn't the most suitable receiver for this, 
but it's fun to see what it's limits are :)


73

Stan
KM4HQE