[R-390] R-390A dB meter as as "S" meter

[Shoppa, Tim]

There is an official S-meter scale that you could calibrate your receiver to. S9 is defined as 50uV into 50 ohms.

But very often any absolute scale is meaningless. Summertime atmospheric noise on 80M where I live is regularly way above S9 using my full 80M dipole. What meaning does a "S9" report to someone mean when he's still less than the noise? And if I have a big antenna pointed right at someone and am getting S9+30, and the guy next door has a little 10 inch whip and is getting S3, by the official scale, yet we're both clearly hearing the guy way above the noise, what does that all mean?

In common use on the ham bands trading 599's with the DX is usually meaningless, and anything reported below S9  is usually subjective relative to band noise. I know this breaks the official standard but it's life. You could spend your whole ham career trying to report S meter readings by the official standards but that's honestly not too fun.

Now, any S-meter does come in handy comparing two of your antennas, or helping another ham compare two of his antennas, for relative readings.

Tim N3QE