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How to Measure With a Wattmeter

In the early days of ham radio, amateurs measured voltage and current consumed by the final amplifier, amperage output to the antenna and antenna impedance, and used this data to calculate output power and efficiency. Modern hams have it easier because of the ready availability of the RF wattmeter. This device allows output power to be read directly at the transmitter output.

Things You'll Need

Transmitter or transceiver
Resonant antenna or dummy load
RF wattmeter
Coax jumper cable

Instructions

- 1
  Disconnect the antenna feedline from the transmitter output. Connect the line to the output of the wattmeter.
- 2
  Connect the coax jumper from the transmitter output to the wattmeter input.
- 3
  Turn on the radio. Tune the transmitter to a clear frequency.
- 4
  Key the transmitter in CW, AM or FM mode. Read the wattage directly from the meter. For SSB power measurement, key the transmitter and say "aaaah" directly into the microphone, in a normal tone of voice, for as long as it takes to get a clear reading from the meter.

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