Steampunk RF Milliammeter

A vintage 1Ω, 200mA FSD ammeter was there, so this steampunk project was taken up.

To start with, the 1Ω shunt and 30Ω series resistors were removed to restore the meter movement's original characteristics (10Ω, 5mA FSD).

The enclosure emerged from a scrapped multimeter housing and a sheet of acrylic. It was easy to work on the acrylic for the required cutouts.

All parts were available in the junk box.

RF Milliammeter - Schematic
The circuit was wired up 'dead-bug' style.

RF Milliammeter
The meter was then roughly calibrated to read around 500 RF milliamperes maximum.

Output of a vintage solid state 15W CW/AM/SSB rig was successfully peaked up using this meter.