I was recently asked how a new repeater operator should choose a PL tone for a new machine. My comments are specific to Northern California, your local situation may vary.
- No assigned tones — We do not assign PL tones here in Northern California. Some places, however, may coordinate both frequency and tone.
- Pick a tone that isn’t being used. A good way to test for conflicts is to connect a radio to the repeater antenna and transmit on the frequency you are seeking, changing the PL tone every time you transmit. This ought to find repeaters on your frequency as well as the tones used to access them.
- Do the same for the repeater pairs one above and one below your desired pair. Why risk interference when it can be avoided?
- Check with your coordinator to make sure you haven’t missed repeaters. In Northern California, you can do this online at the www.narcc.org website. I don’t trust the RF Finder database and app for any purpose. Just too inaccurate.
- Yes, you should transmit a tone and your users should use it — Sometimes VHF and even UHF signals propagate over long distances. When this happens, users will unexpectedly hear another repeater on “your” frequency. Transmitting a PL tone (the same as the tone used to access your repeater) goes a long way to solving this on-channel interference issue.
There is probably more to this than I have talked about. So leave questions or comments and I will answer them and then change this post to reflect the new information.