Yes they did the same with transmitters, often all you need was a
metal mop bucket and a piece of copper pipe
Jimmie

A water load bank is good for hundreds of KW at 60hz.

For use with a pair of 6146's we used to wire a lamp to a coax
connector. We had a load as well as visual indication of the relative
power output.- Hide quoted text -

- Show quoted text -

I built a wattmeter of sorts around a circuit like that. After tuning
up the transmitter to light bulb dummy load I would measure the
resistnace of a photo resistor exposed to the light then see how much
60Hz AC voltage and current took to light the lamps to the same
brillance.

Jimmie

if you were really good you could estimate the power from the brightness
in real time. it did take a lot of practice.