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

[TF3KX]

I would like to use the K2 or the K3 occasionally as a "field strength
meter", for example take the rig a couple of km/miles away from my QTH and
record the signal strength from my home station.  This would be useful in
antenna experiments.

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?

For example, I have made calibration curves for my IC746, which gives me
internal S-meter readings from 0 to 255, and I have made corresponding dB
charts.  It appears to me that the K2 gives only figures from 0 through 10
using the BG (Bargraph Read) command, which is too coarse for such
measurements.

Any further info on this - for the K2 or the K3?

73 - Kristinn, TF3KX
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[KK7P]

> 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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