Internal K2/K3 S-meter resolution for computer recording?

[TF3KX]

Thanks, Lyle.

So, to make sure I understand this, all of the measurments (dBV and AFV) are
done at the same point, at an AF level that is independent of the AF gain
control.  Furthermore, by turning the AGC off I will have a relatively
linear relationship between the RF input level at the antenna and this AF
level that is measured.  That would do it for me.

Just to press this further, however - I presume the K2 is limited by only
providing those 10 discrete steps of "signal strength"?  I don't have a K2,
but it has still some appeal in being more portable (built-in battery, low
RX current, smaller) for field operation and measurement.  Comments, anyone?

73 - Kristinn, TF3KX


>* So, the question is:  How much internal resolution of the S-meter reading
do
*>* we have in the K2 or K3 (or other Elecraft rigs, for that matter), that
*>* could be read by a computer?
*
*You can go one better with the K3.  It has an internal dBV output which
is based on a true RMS voltmeter function.  This will eventually be
readable by software.  So, you set things up, perform an "AFV" (AF
voltage, not affected by the AF Gain control, fortunately) measurement
to get your reference level, then switch to dBV and see it is around 0.0
(with some bobble due to noise, etc.) Now increase or decrease the Tx
output of the thing you are measuring (or swing the beam, or...) and get
the result in dBV referenced to the first measurement.

As long as the S/N is reasonable, you can measure over a pretty wide
range of signals.

Of course, you'll want to have AGC off when you make this sort of
measurement so the AGC compression doesn't affect the AF voltage.

And, yes, since it is an AF voltmeter, you can use this to measure
insertion loss of filters, effectiveness of notch, etc.

Enjoy!

Lyle KK7P
*
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[Ingo Meyer, DK3RED]

Goðan daginn Kristinn,

> Just to press this further, however - I presume the K2 is limited by only
> providing those 10 discrete steps of "signal strength"?  ...

Thats right, but I think that this information is enough for the RST rapport. If a
LED flickers (because the SWR is not exactly a discrete value) you can send i.e.
RST 45/69 or QSA 5/6.

Sælir!
--
72/73 de Ingo, DK3RED - Don't forget: the fun is the power!

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