Methods of Antenna Detection

[HardwareChap]

I've seen antenna detection done where a pull down resistor is built into the antenna to detect if an antenna is present or not. If say I was using an off the shelf dipole antenna (no built in resistor), what would be a good alternative way of being able to detect if that antenna was connected or not? It would be connected to an N-Type (or maybe SMA) connector without a mechanical antenna detect, so I'd be looking to do this discretely.

 

[biff44]

an inductor to ground will do it

 

[jiripolivka]

I've seen antenna detection done where a pull down resistor is built into the antenna to detect if an antenna is present or not. If say I was using an off the shelf dipole antenna (no built in resistor), what would be a good alternative way of being able to detect if that antenna was connected or not? It would be connected to an N-Type (or maybe SMA) connector without a mechanical antenna detect, so I'd be looking to do this discretely.

Depends on what point is desired. If you need to detect antenna connection to a device like a transmitter, use a SWR indicator or a reflectometer. A matched antenna will generate a low SWR response, a disconnected antenna a high SWR output.

Another problem is to detect antenna presence in a remote location. Again antenna matching is important but a radar-type device is needed.