"David Huisman" wrote in message
...
Hi,

I am looking for some ideas for a low cost circuit to detect if an antenna
has been broken or removed
from a 10mW transmitter.

Initial thoughts are to measure SWR but I need a small, low cost circuit I
can place between PCB Antenna connector and the antenna.

Thanks in advance for any assistance

Kind Regards

David Huisman


I'm the lazy sort. I'd get a 1N34 diode, a capacitor, a resistor, and either
a surplus microammeter or one of those cheap little digital panel meters.
Build an RF voltmeter. 10 mW into a 50 Ohm load should cause about 1 V of RF
when peak rectified. That's enough to read on a meter through the diode. It
doesn't matter what the meter reads--just jot down the value when you know
the antenna system is right and then watch for changes.

You must be a QRPer. Someday I hope to get my homebrew Micromountaineer (.5
W) on the air.

Have fun.

John