One more comment about accurate power monitoring. If its a CW level,
then a laboratory grade power meter such as HP437 or the newer
models, is recommended. One that has been calibrated to factory
specs. Then use a large BIRD Tennuline power attenuator (sorry for
the bastardization of the spelling?). The attenuator can readily be
characterized using a calibrated network analyzer. This can get you
to better than a few % I believe. The attenuator is a nice 50 Ohm
load for the TX, and reflected power from the power meter head is
even absorbed in the reverse direction - not that it matters much at
that level of dilution.
A water calorimeter is a nice way for really high power, but it is
fraught with potential errors when the flow is fluctuating, or the
temperature differential to the load is only a few degrees. One has
to built a custom device, or talk to people like Bird, Electro
Impulse, Altronics, etc.
Now for SSB and pulsed RF, one can still use the attenuator, but the
power meter should be a peak reading model. Again, they can be had
for $$, to laboratory calibration grade.
I brought all this up, because the impression that I got reading here
was that even the FCC couldn't tell what the output power of a rig
was, to much better than a 43 wattmeter with peak hold. This is
untrue, as most laboratory/commercial/military transmitter
manufacturers can vouch for. It all depends on how much money they
want to spend on test equipment. Sure, a $300 power meter is going to
get you within 10%, but you need to spend about 10-20 times that for
1%.
73
K5PRO
John
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