A type F coax switcher that grounds unused inputs will work.

On 11 Sep 2003 07:21:43 -0700, (TommyBoy) wrote:

I had an earlier post about fabricating an antenna switcher for my
random wires, and one of the suggestions was to try the $11 RS a/b/c
video switcher. I did and there was no isolation at all. Don't waste
your time with this one.

I eventually put together a switcher using toggle switches. Works
great. Now I just need to make a nice finished case since I know it
works well.