Either use a TDR, or something that measures RF impedance - an SWR
meter, an impedance bridge, an antenna analyzer, or even a signal
generator and a scope. Sure there's a path for current flow, but only
for sure at RF, so that's where you have to detect it.

Roy Lewallen, W7EL

Don Baker wrote:
I would like to be able to determine if antenna is present at the end of a
piece of coax. In some case antennas of type ?? would have a DC resistance
across the coax and that makes it easy. But..., how would you easily
determine if a coax shows an infinite DC resistance (NO RETURN PATH) no
current flow - like simple did-poke.

Trying to spare the group all the details of what I am doing but I will
gladly answer any questions. Thank you in advance for your help.

Don