David,

If your antenna has DC continuity, put DC on the feedline through an RF
choke and resistor. Do it like this: DC voltage to resistor to RF choke to
center conductor of coax. Red LED from junction of resistor and RF choke to
shield of coax. The red LED will come on when the path is broken. If the
antenna normally does not provide a path, connect anothe RF choke at the
antenna, in such a way that whoever steals the antenna also takes the RF
choke. You want the RF chokes to be PARALLEL resonant somewhere just above
the operating frequency.

Tam/WB2TT
"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