A simple electric field indicator circuit
This electric field indicator can be used instead of a wavemeter that requires to be tuned to a radio station frequency. The device is way easier in use, it helps to adjust a radio transmitter or radio microphone. Mount it in a tin can, it would be a "ground" and a shield. Use a wire of 150...250 mm in length as an antenna. Any sensitive microammeter can be used as an indicator, just like a recording level indicator taken from an old type recorder.
Fig 1.
Both diodes D1, D2 are germanium 1N34;
C1 - 1 nF; C2 - 15 nF.
The device doesn't require any adjustments, it can help to tune transmitters with power more than 10 mW and frequency less than 60 mHz.
G. Shepelev
"Radioamateur" magazine, 1993, June.