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  Radio Experimenter Theory Notes

Absorption Wavemeter

Knowing the crystal frequency is not in itself sufficient because there is the possibility that the final output from the transmitter may be on the wrong harmonic of the frequency.

The absorption wavemeter detects the presence of harmonic radiation by tuning the variable capacitor. The meter will deflect in the presence of harminic radiation. This may also be called a hetrodyne wavemeter.

Operation

When the antenna is tuned by the variable capacitor, the diode acts as a detector and produces a voltage which causes the meter to deflect.