I've noted for many months now that in my area 167.5875 (CTCSS 167.9), keys up once every 40 seconds or so, with a dead carrier for about 1 to 2 seconds. Is there a reason now for these keyups? (e.g. does it display radios numbers in range and/or indicate to units that they are within range of that specific site?). Ken Springfield MA Monitoring Area