I just read out the power via RS-232 with the calibration at the nominal
value of 500 and then again with the bogus calibration value to see how
much it changed. The calibration value is not linear - I think it is
proportional to the detector voltage, which is roughly proportional to
power squared. (650/500)^2 = 1.69 and I measured 1.6.
Alan N1AL
On 11/20/2015 09:44 AM, Cliff Frescura wrote:
Very cool Alan! Did you verify the power with another reference meter?
...wondering if the scale adjustment is linear over the calibration setting
range.
73,
Cliff K3LL
-----Original Message-----
From: Elecraft [mailto:[email protected]] On Behalf Of Alan
Sent: Friday, November 20, 2015 9:07 AM
To: [email protected]
Subject: Re: [Elecraft] Rescaling the W2?
I just tested it. The maximum you can set the W2 calibration value to is
650. (Using the ">" and "+" RS-232 commands) That causes the wattmeter to
read about 60% high on my W2. So with the W2 set to read 2000W full scale,
the actual full scale would be about 1250W.
Or you could go in the other direction. The minimum calibration value is
350, which causes the power to read about 47% (on my unit). With the
W2 set to read 200W full scale it would actually be about 425W full scale.
Alan N1AL
On 11/20/2015 07:15 AM, Cliff Frescura wrote:
I find the scaling awkward as well. My W2 is placed on the input side
of my
KPA500 and it seems that dividing the scale by two might do the trick.
I've not looked at the schematic, but wonder if it could be tricked by
a resistor divider in the sensor line.
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