I have a tone coming across a single talkgroup at 10-second intervals on a trunked system. The radios on this talkgroup are not displaying any messages, and dispatch is not seeing any particular radio broadcasting any alarms. This happened about two months ago and only lasted for a day. Now that it has started again, it has been continuous for about two weeks straight, and I am at the end of my rope. I was dropped into this role with no training outside of using CPS, so I am still learning. Any help would be greatly appreciated.