[R-390] 17mc Crystals

[roy.morgan at nist.gov]

Quoting Flowertime01 at wmconnect.com:
> There are two 17Mc Crystals in the R390's.
>...
> They have a difference in temperature ratings and thus a different part 
> number.

Roger,

This is good to know.  Off the top of my head, I do not know the temperature the
multiple crystal oven on the Crystal Oscillator module runs at. If the samples
of small octal plug-in ovens I have at hand are right for R-390/URR (26.5
volts) and R-390A/URR (6.3 volts), then they all operate at 75 Centigrade.


> That has all run through the mail before and we need to get it all over to 
> Wei-Li's   
> Pearls.
> 
> If you are not operating your receiver in a "harsh" environment the 
> temperature range is not an issue as you have the heaters off and the "oven"
> containers are running over room temperature

BUT,note that The "OVEN" switch on the back of the R-390A does NOT control the
17 mc and 200 kc octal plug-in oven.  It does run both the Crystal Oscillator
module oven and the PTO oven.

Roy
K1LKY

Roy Morgan
13033 Downey Mill Road
Lovettsville VA 20180