[Elecraft] K-3 S-Meter Absolute test

[Mike Scott]

I thought I would pass on the results of my testing the absolute S-meter
mode using the XG2 signal generator as reference source.
I am using beta FW 01.96/00.02/0.173

The VFO-B help menu for Smtr scale says that the S-meter is calibrated with
preamp on, and AGC on. It looks from my data that my unit S#508 the
calibration is consistent with pre amp off, not on. Was there a change? 

Test results using default S-meter parameter settings and AGC on are below.
Filter used for this test is the stock 2.7 KHz 5 pole. Test was done on 40M,
F = 7.040 MHz with receiver zero beat to tone (using 50 Hz bandwidth to zero
beat).
I notice that with 500 Hz filter and 6 Khz filter settings that all
measurements below move down an S, see note below.

Smtr mode = Nor
Pre Amp off, ATT off
50-uV = S-9
1-uV = S-3

Smtr mode = Nor
Pre Amp on, ATT off
50-uV = S-9 + 10 dB
1-uV = S-5

Smtr mode = Nor
Pre Amp on ATT on
50-uV = S-9
1-uV = S-3

Smtr mode = Abs
Independent of ATT or Preamp settings
50-uV = S-9
1-uV = S-3

I like the absolute mode and will leave it there. Since running this test I
have adjusted filter gains of the 6 KHz and 500 Hz filters up by 3dB to
equalize the S meter readings (and audio) independent of filter settings.

Mike Scott - AE6WA
Tarzana, CA (DM04 / near LA)
K3-100 #508/ KX1  #1311