[Elecraft] K3 S Meter

[Guy Olinger K2AV]

No standards.  There is no international body in charge of the definition of
an S-unit.

Just history.

Somewhere I have a .jpg file from an ebay posting of a lovely pristine 30's
receiver with an S meter that showed S units on top side of scale, and dB's
on the bottom side.  6 db per unit.

The very simple origin of that was that moving up an S unit was doubling the
signal voltage. Given circuits back then, the bottom of the scale was the
point at which AGC intercept occurred.

The "about" portion of the S3 in the K3 doc comes from not having strictly
calibrated RF gain until just a few beta firmware releases ago.

After the calibration, my K3's S3 light kicks on at input of -109 dBm, and
S4 kicks on at -103.  1 uv exceeds -109 but falls short of -103, thus only
showing up to the S3 light.

If one is thinking that S3 *IS* -109, then 106 or 105 or so is "about" S3.
If one is thinking that S3 is a range, when the S3 lamp is on then it's S3
(exceeds -109 but not -103 dBm), then by definition S3 is fuzzy.

Use of the word "about" is a lot more straightforward for doc than what I
just said. Another example of when less is more.

73, Guy.

On Tue, Nov 17, 2009 at 1:45 PM, Mike Scott <mike at paxsen.com> wrote:

> Geoff said>For practical purposes S3 is probably close enough rather than
> "about S2 or 3" as shown in the manual. Or is it more complicated than
> that?
>
>
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