Scanner sharing antenna with VHF Radio

[Dispatrick]

I am trying to figure out how to use a scanner with a vhf radio on the same antenna. Currently we are using the scanner with the vhf radio, however the antenna is immediately hooked into a duplexer and the VHF side going to the VHF radio and the UHF side going to the scanner. The problem is their is only one antenna and we want the scanner to receive not just UHF. Is there a way to put a splitter prior to the duplexer and have that one line run to the scanner?

I am aware this could blow the scanner out if using the VHF radio to transmit. Is their some type of device I could put on the line going to the scanner to protect it from the power from the VHF radio going into the scanner? if it matters it is all Type-N connectors and the line coming off the UHF side of the duplexer is using an adaptor to convert it to BNC.

 

[jonwienke]

You really need separate antennas and feedlines. A VHF antenna for the TX radio, a wideband RX antenna for the scanner, and they should be as far apart as possible.

 

[mmckenna]

There are ways to do it.
None of them are easy. None of them are cheap.
You can install filtering that blocks out the specific slices of frequencies that the VHF transceiver uses, however they aren't perfect, so they'll block/limit some stuff on either side. They are also specific to where they are tuned, so that means your VHF transceiver is stuck where it is.
The hardware to do this is large. It takes special test gear to set up.

Compare all that to the price of a new scanner antenna and cable/installation, and you'll see why guys like Jon and I will tell you don't even bother chasing that option. It's a pain, it's expensive, and it severely limits what you can do.

 

[jonwienke]

They will also prevent the scanner from receiving any frequency near the one(s) used by the VHF radio.