I have a Yaesu FT-857 Amateur Radio transceiver which has an output for an Analogue Moving Coil meter.
The radio will output a current varying between zero and 1 milliamp (0–1mA), depending on the signal strength received by the set. This is intended to drive the coil of an analogue meter. 1mA indicates a very strong incoming signal, values below are weaker stations.
The spec doesn't give a voltage, but I've measured that this varies between zero and five volts (0–5V). While it does appear that the voltage also varies with signal strength, it's not mentioned at all by the spec, and I'd like to stick to measuring the current, for the definitive value.
What's the best way to measure/sample this signal, so that I can use the Current value in an Arduino, to create a digital coil meter with a 7-segment display?
Note: This transceiver does provide the value digitally using CAT, a serial data link. For reasons I won't go into, I only have the analogue meter line available.