[TenTec] Displayed frequency question

["Hulett, Russell" <rhulett1@consolidated.net>]

I own an Omni D, Omni C, and 544.  For all three WWV is zero beat at 21.000.  
For all three, frequency displayed for sideband signals matches net frequency.  
In every case, CW frequency displayed is low by .7 khz.  W1AW comes in at 
7.046.8 That is with zero beat function on and tone zero, or zero beat function 
off and tone matched, the frequency readout is low as compared to the frequency 
reported by third party ( like a skimmer ). skimmers.

It's really not an issue, I just always accout for the offset, but am curious 
what the explanation might be.