How the memory slips! We used to use light bulbs as dummy loads. It
requires some experimenting and measuring to find bulbs that present a
suitably matched load for a given power, but they work fine if they are
always used to sink power over a small range, like 2:1. For a bonus,
they provide a visual indication of the power level, too.
Low wattage incandescent light bulbs were also linked loosely to
transmitters to serve as transmission indicators, and they indicated
operation of AM modulation. These were found on many commercial
transmitters and transceivers, including several models of aircraft VHF
transceivers. I recall the Narco SuperHomer, with four transmit
frequencies! Let's not talk about how many times pilots (excluding me,
of course) were on the wrong frequency, given all that choice. Of
course, the receiver was tuned with a crank and a dial. If the
frequency was quiet, the pilot had to ask a ground facility for a slow
count, for tuning the receiver. Then, Narco added whistle stop tuning,
but that only worked to tune the receiver to a frequency for which the
transmitter had a crystal. No frequency synthesizers in those days.
Roger, I bet Roger and others can tell stories about those radios.
When the statute of limitations runs out, I'll tell about using ham gear
for aviation HF communication while crossing the Atlantic.
73 de Red
TowerTalk mailing list