Antenna Resistance Question

[zonian149]

If I attach a vom meter to my antenna's coax at the end that I connect to the scanner and measure the resistance will that tell me any useful information?

 

[N_Jay]

If I attach a vom meter to my antenna's coax at the end that I connect to the scanner and measure the resistance will that tell me any useful information?

NO!

 

[N_Jay]

If I attach a vom meter to my antenna's coax at the end that I connect to the scanner and measure the resistance will that tell me any useful information?

NO!

Oh wait, I'm wrong.

It will tell you if the battery in your VOM is any good. Thats usefull information.

Oh wait, some antennas are DC open, So it won't tell you that either.

I'm back to; NO!

 

[SCPD]

Depending on the type of antenna, it would be open or shorted. If you already know that, if you are troubleshooting, you can verify that that is indeed the fact or otherwise. 8)

 

[DaveH]

Yes, it can.

If you have an antenna that is dc-grounded, it should register as a fairly low dc resistance, due to the coax, connectors (a few ohms at most). If the antenna is open, or the coax is broken or disconnected, you will read high resistance (maybe not infinite, due to some leakage).

The converse is true, especially if you're just installing the antenna/coax. If the far end hasn't be connected, and you read a short, the coax/connectors may be shorted. This has happened to me in past. You won't be able to read the antenna impedence e.g. 50 ohms because that is the "radiation resistance" not the dc resistance. You'de need an antenna analyzer or other fance test gear to tell you that.

Dave

 

[zonian149]

Discone Antenna

I have a discone antenna that I added a CB antenna to the top of it and was just curious what the reading on the meter would tell me. Porbably can't justify an antenna analyzer sounds like a neat toy though.--Gary