For the following, I would suggest this:
Use a Delta Electronics TCT current transformer to get the current
component. Or use a Pearson current transformer. Use a voltage
divider (like the Jennings glass vacuum capacitor unit) and a meter
with 2 MHz accuracy (such as a good old Hp 400C) to get the voltage
component at the base. These would give you the VA. Use a network
analyzer, impedance meter, antenna analyzer, or the knowledge of 10
ohms in series with 250 pF if that is accurately determined) to get
the phase angle, and use that to correct the calculation for real
watts.
Obviously it would take some work, but if you want to do this, you
have to be able to come up with some stuff to do it. Most would
measure the power in the transmission line before the remote tuner
unit, where it is nearly 50 ohms, with a directional coupler or
wattmeter like Bird. Then assume some sort of efficiency through the
network, say 95%?
>G3rzp@aol.com wrote:
>
> > For real fun, how do you measure the power (with what accuracy?) into
>> a load such as marine antenna at 2MHz?
>
>No idea.
>
>> The dummy load is typically 10 ohms in series with 250pF: a DC
>> calorimetric method might do to calibrate the resistive part, but the
>> RF and DC resistances are probably slightly different.
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