Thanks to all those who responded to my query about the apparent 
errors seen on frequency standards.

I am now convinced my problem is caused by frequency error in my TS-
850. Looking at several standards, the errors are as follows 
(relative to an arbitrary zero):
60.0kHz:        -1.0Hz
75.0kHz:        -0.8Hz
77.5kHz:        -0.7Hz
162kHz: -0.1Hz
198kHz: +0.1Hz
490kHz (using my LF Tx DDS) +3.0Hz
Plotting this on a graph shows approximately a straight line. This 
indicates a progressive error as frequency increases. 

As a quick fix, I can now use the graph to determine the readings at 
198 and 60kHz that will give me a zero offset at 136kHz. However, is 
there a more permanent way of overcoming this problem?

Mike, G3XDV
==========



> Nothing unusual seen here - checked against my Rb standard.
> Walter G3JKV.