What frequency is Channel 4? I frequently hear the Sheriff's dept say "Go to Channel 4" but can't find freq......
It is possible that it is a simplex channel, and unless you are close by you probably would not be able to hear them.
My local city police, Newport TN, have a Ch.6 they go to which is simplex. I live about 7 miles from town and I only get a peep from time to time when they use that channel.
I would try to do a seach when they go to channel 4, 460.00 to 460.500.
If you hear nothing there then try 465.00 to 465.500, some agencies use the repeater input freqs as simplex channels.