Change graph signal levels from "dBm" to "dB"

[jdow]

The mailing list has at least one person who is confused into thinking that the scale means something except in special cases. He's concerned that the scale is not the same locally as through the server when the scale is uncalibrated in 99% of the use cases. That 1% is people who are in a position to actually calibrate the scale.

So changing from dBm to dB could mitigate that problem.

{^_^}

[Simon G4ELI]

Which graph?

[jdow]

Actually all places dBm is used, Spectrum display, S-Meter, more spectrum display, and so forth. MAYBE make a button in configuration that says, "Cross my heart and hope to die, yes I did calibrate using Visual Gain settings and an external reference."

On your web site you could note that the raw dB with no visual gain correction through calibration is roughly speaking 0dB for a single pure sine wave signal that brings the A/D converter to full scale. Visual Gain is the tool you can use to calibrate the spectrum for a given front end and gain settings.

Now, it would be really "spiffy" if you could track gain settings and correct for them in the display. But, then, SDRC is a sturdy work horse not a prancing stallion piece of test equipment.

{^_^}

[Simon G4ELI]

That's quite some undertaking - changing dBm logic to dB. I'll bear this in mind, not for 2020 though.

[jdow]

The simple thing I am thinking of is literally a single global string change, "dB" for "dBm". That's the easy part. The hard part is finding locations in the code, if any, that are accurate enough to actually be "dBm" through precisely known and tracked gains. The really hard part is determining the cases, such as I'd be, where it really has been calibrated to read dBm.

After the string change a faq indicating that some effort has been made to have out of the box default settings more or less read dBm; but, conditions out of the author's control suggest "dB" is the best scale marker. If a person has gone through the labor of calibrating it all, they can mentally see dBm when they see dB. It's the newbies who see dBm and presume it means something real who get confused.

{^_^}

[Simon G4ELI]

Sorry but not now. We can talk about this later, at the moment I'm in an area of code where I really must concentrate.