Mark and Tom, I think you have steered me to the answer for the dBm question, the AD2 physically just has two analog inputs, they can be scope ch1/ch2, or SA, or whatever but they are designed as scope inputs.? My signal sample comes from a 47dB tap on my dummy load (home brew from parts which is why the odd number of dB).? Assuming my decibel math is right -- which is a stretch -- uBitx is putting out nominally 7w (antenna SWR meter says) == 19V @50Ohm == 47dB down is 0.080V, 80mV.? I see this on my tek 2246 scope, plus/minus calibration (it goes without saying none of this equipment is calibrated!).? I put this into the AD2 to look at spectrum as above.? I was checking the AD2 manual to make sure I wasn't blowing it up, which it said it was ok, and that now makes sense since these are designed as scope inputs.? I have a kit step attenuator, which let me put another 60dB in front of the AD2 (again assuming decibel math correct, that should be in the vicinity of 50uV).? It didn't look like it made any difference, which I think makes sense now.?
Whew, this uBitx assembly is really living up to expectations for making me learn (!).? According to the manual it will do cursors, I have to go find this feature.
--Ron
K0EIA
