Hi Tom,
How are you measuring from the IF tab? RTL-SDR dongle?
wfview does not have this capability yet. We are simply reading out from the radio’s provided spectrum display. However, I can see adding somethings like this in order to expand the supported radio list considerably. There are many SDRs which provide I&Q streams, for example, and from that one can Fourier Transform and get a nice spectrum display.
If you’re using an RTL-SDR for the IF sample, there may be a way to remotely grab that data.
–E
de W6EL