True Received Frequency


Steve VA3FLF/KM4FLF
 

So I noticed last week that another frequency measuring test was conducted by K5CM and I assume sponsored by ARRL. Not really thinking the process through I measured the frequencies for 40 and 20 Meters using DM780 from HRD. Afterwards I realized that I would have and did make an error. If I am using USB to look at a signal, then I am really inserting an audio / side band error. 

So sure enough, I was 23 Hz off on 40M and 57 Hz off on 20M. So I noticed on DM780 you can select the frequency for the waterfall or select Hz from the base frequency. If you select frequency DM780 allows you to enter an offset to adjust the frequency across the waterfall.  Here are my questions?

Example, My radio is set for 14.070. I see a trace on the waterfall at 1000 Hz. This should translate to 14.071. But if we are using USB is there an error being inserted to the true received frequency?

How is that offset or error measured?   I would assume that since I am selected 14.070 USB, I am not really on 14.070 am I?

Something to change the subject and put on thinking hats...any thoughts?

Steve
VA3FLF
2301

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