Just a quick note: while changing "Audio gain" in band config. menu from the terminal, I observed that the S-meter and the AGC are heavily affected by it, i.e. if I set 0dB of "Audio gain", there's barely any S-meter or AGC action displayed on the screen. This can be also be observed on "The Lab" (see what you have done? :-)) )
OTOH, if I change the "Audio atten." value, S-meter and AGC level seem to be unaffected by it. Is this how it's supposed to be? I'm thinking that, at this momemnt, if you're changing "Audio gain" to anything other than the default value of 54, the S-meter is losing it's calibration. Or so it appears to me, I'm known to have been wrong before :-))
Yes, you are correct. But this is also how I have declared that the system works. If you look in the operating manual section on the AGC I described all the stages the signal goes through from the antenna BNC port through to the 3.5mm earphone output. You'll see that I said the band configuration gain value comes before the AGC action. The audio attenuator and volume control gain come later. This is why they don't affect the S-meter. So the intention was that the band configuration gain can be used to equalize and calibrate, to cancel out any differences in BPF attenuation etc between the bands.?
On my unit a band configuration gain of 54 on 40m calibrates the S-meter correctly. Note that the S-meter is logarithmic with 6dB/bar. This doesn't depend on anything in band configuration, it's linearity as 6dB/bar is always accurate. But the number of bars for a given level such as S9 would vary and that's what needs calibration by adjusting the gain in the band configuration screen.
So what you observed is the correct behavior for how the system is written now. But if you think I should improve it somehow please let me know.?
And one other thing, if I set the "Audio gain" to, say, 30dB on one band and 0dB on all other bands, the audio seems to honor the 30dB for all bands. The reverse is also true, If I set 0dB on one band and 30 on all the others, the 0dB seem to take over
Yeah that really doesn't seem right, I should have to look into that.?
