Being a bit of an antenna fan, and finding myself yomping up hills with bits of wire, PVC pipe, tape measures and all the other paraphernalia we seem to press into service for getting our signals out, I thought it might be time to get myself a field strength meter. I want to homebrew it and make it nice and compact to fit into the SOTA bag. I’ve had a scout 'round on the net and found a couple of designs, but they mostly seem to active (I’d quite like a passive FSM, although its not the end of the world if not) and seem to stipulate that they are designed for VHF. I’m wanting to use mine for HF too.
To this end I had a look through the pdf manual for the MFJ-802 and it seems to me to be nothing more than a germanium bridge rectifier with a couple of telescopic whips on the input and a .1mic capacitor and a milliamp meter biased with a potentiometer across the output. Even I can do that! And for lots less the 50 quid.
Am I over-simplifing things? Can I just lash one up out of bits? Does anyone know of any more schematics kicking around? All thoughts and comments welcome… =)
Thanks and 73,