Mike Dennison wrote:

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.

I found the callibration on my 850 was out by about 1Hz on 136kHz. I
also found the callibration on other frequency standards were also out
by different amounts, depending on frequency - very similar to Mike's
results.
Furthermore, the receiver required at least 30 minutes warm up for the
frequency to settle.
The frequency calibration on the DDS of my IC-706 and FT-817 is more
accurate.
However, having said that, the 850 performance on LF is so good that
applying an small frequency offset is a minor inconveniance.

Peter, G3LDO