"JIMMIE" skrev i en meddelelse
...
I have a Homebrewed SWR meter I was thinking of calibrating it to read
power by appling a dial for the "full scale adjust" potentiometer.
Meter would be initially calibrated against a know accurate wattmeter.
Variable HIgh Power RF source would be an Amateur band SSB TX
modulated by a single tone audio source. Power varied by adjusting the
level of the tone. Power would be read from the dial pointer. One
thought is to use a difference meter reference for each ham band ....
10M full scale 15M a little less. Any thought s on this method would
be appreciated.


Jimmie

dr Jimmie,

From your last remark I guss that your SWR meter bridge principle consists
of some kind of coupling pick-up loop where the RF output versus frequency
is not flat but follows a +6 dB/octave characteristic, i.e. more sensitive
as the RF frequency rises.

In that case you have you have two options: Calibrate the meter individually
for each amateur band or pass the coupled RF through a -6 dB/octave low pass
filter beforde detection.

It might be easier to add to your SWR meter a separate RF detector to sample
the RF at the main line. This is easily made (mostly) frequency independent
and it can be calibrated separatey from the SWR part. You will of course
need to add a switch in order to change from SWR to power readings.

vy 73
OZ7S Sven
Technical Editor Emeritus
OZ Magazine