RF Field Strength Meter
Untuned RF Indicator/Field Strength Meter - Aug 1995
A simple untuned RF indicator, or relative field strength meter, can be constructed from your junk box using the circuit opposite. The indicator can be mounted in a biscuit tin, plastic box or for a really cheap job, the components can be mounted directly on the terminals o f the meter.
Nothing is critical about the unit. It should work up to 2 meters; the only constraint is maintaining an appropriate distance from the antenna you are checking.
Using a one milliamp meter is about the optimum; anything more sensitive and you risk burning it out, anything less sensitive and the meter loses its utility. In any case, its up to you what you use - substitute and enjoy.