[Elecraft] S-meter calibration

[W3FPR - Don Wilhelm]

Folks,

I would add to what Ron said that the AGC Threshold setting also has a great
influence on the S-meter.

It is possible to 'twiddle' with the AGC Threshold pot, CAL S Lo and CAL S
Hi settings to obtain most any S-meter reading you want.

CAL S Hi alone can be adjusted to produce the S-9 at 50 uV indication, but
when doing only that, the s-meter range can be constricted or expanded if
the other settings are not correct, resulting in an S-meter that is correct
only at S-9.

I usually adjust the AGC Threshold just below the point where there is no
change between AGC on/off (no antenna connected) - the voltage will be
somewhere between 3.65 and 3.8 volts.

Then set CAL S Lo for no bars showing (RF GAIN set full clockwise and no
antenna connected)

Then set CAL S Hi for last bar lighted with RF GAIN at minimum.

Checks with a 50 uV signal afterwards usually produces an indication of S-9
+/- 1 LED bar for me.  If I want it any closer, I set the AGC Threshold up
or down by a small amount (measure the voltage and move it only a small
voltage at a time - 0.05 volt to 0.1 volt steps only), then re-do the CAL S
Lo and CAL S-Hi - repeat until the desired S-meter readings are obtained.

A bit more involved that the simplified steps in the manual, but then if you
want precise results you have to work at it a bit harder.

73,
Don W3FPR

> -----Original Message-----
> ...
> Set your GR-1390B for 50 uv output and adjust the S-meter MENU settings on
> your K2 for S-9.
>
> It's also useful for Spectrogram adjustments, just like the
> Elecraft N-Gen.
>
> Ron AC7AC
>
> -----Original Message-----
> Hi Elecrafters,
> I've been given some old instruments, among them a GR1390-B
> random  noise
> generator :
>      - Maybe it could be of some help for S-meter calibration of my K2?
>      - Or for something else in the radio field ?
>   72,
>