[Swan] SWR-1A Operation

[Bob or Chris Balonis]

Hi David,

At one time I did have what looked to the identical meter, but with a
different manufacturer's name on it (which I of course do not remember).

In any event, I did go through the trouble of calibrating it by affixing a
numeric scale to the sensitivity adjustment know and than calibrating each
band of interest (using a dummy load) for the available RF output powers
that I had (400 W and less in my case) - e.g. in my case, I adjusted for
full scale - 400 W (or whatever was a nice round number on the band of
interest - I probably only got 200W on 10 meter's).  Of course you either
need a known calibration standard to measure power to adjust the sensitivity
for full scale (or a accurate o-scope to compute power at the dummy load).

It seemed to work quite well - even with the rather crude adjustment
accuracy of the sensitivity knob.

Note that most wattmeters are pretty inaccurate anyway (see some of the
reviews in past QSTs).  Note also that when not on a dummy load, the forward
power reading that is indicated by the meter includes not only the forward
power but the reflected power phenomenon, which is added to it - so if you
have a higher SWR antenna the power reading you get will be higher than that
you achieved during calibration using a 1:1 SWR dummy load.

Hope this is of some help - Bob  NB3W


----- Original Message ----- 
From: "David Patton" <david_okay at msn.com>
To: <swan at mailman.qth.net>
Sent: Friday, February 04, 2005 11:02 AM
Subject: [Swan] SWR-1A Operation


> I just purchased a Swan SWR-1A meter, sans manual.  Is this meter a
relative
> power meter only? It appears to have power level markings on the power
> meter, but there is no calibration markings on the one adjustment.  All
> comments, suggestions, and words of wisdom are welcome!
> 73,
> ~ David
>
>
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