[AMPS] S units

[Peter Chadwick]

I believe the S9 = 50 microvolts predates KW Electronics by a long time. In
any case, it wasn't unknown for S meters there to be 'calibrated' so that
they read in accordance with a subjective assessment of the signal!

One difficulty, especially in those days (50's, 60's, 70's) was that front
end gain varied wildly from LF to HF bands, because of tuned circuit dynamic
impedances. This tended to make meaningful readings pretty pointless. I
guess even today the figures don't mean a lot, anyway - although it screws
up some logging programs if you give a  567 report in a contest!

The 'S' stands for Suspicious!

At one time, for what it's worth, Eddystone used (so they claimed) 4dB per S
unit.

S meters, like many SWR bridges, given half a chance, lie like a Personnel
Manager. (or 'Human Resources', to give them the modern pretentious title)

73

Peter G3RZP



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