Oct 18

Attention Users of 146.925

As most of you have probably noticed by now, there seems to be some interference taking place on the 146.925 repeater. This seems to take place only after dark, and seems to be a combination of some other signal combining with the output signal of the repeater, which is then heard on the input side of the repeater. Due to the DSP delay in the repeater, when this happens the repeater will begin to reverberate its own audio. (When someone unkeys, it’ll sound like they are in an echo chamber.)

Up until a few days ago, the repeater would hang anywhere from 30 seconds to a few minutes, blasting this noise over the airwaves. As you know, the repeater requires a PL tone of 114.8 to access it. The repeater also normally transmits a 114.8 tone on the output, allowing you to use “tone squelch” to keep out interference and the noise created when people use the repeater in digital mode. However, this output tone was also keeping the repeater open whenever the nighttime interference took place.

As a result, the output tone of 114.8 has been temporarily removed from the repeater. If you have your radio set up for “tone squelch” on the output of the 146.925 repeater, you will no longer hear the repeater. You will need to disable this function on your radio to hear the machine. You must still transmit a tone of 114.8 to access the machine (don’t turn that off, or you won’t be able to access it!), but the machine will no longer send a tone back to you.

This has kept the machine from hanging itself up all the time. However, the interference is still there (and we’re working to track down the source), and is affecting users’ ability to access the machine from far away locations using an HT. (You’ll notice it sounds like someone is “doubling” with HT users.)

Once the interference problem is resolved, the 114.8 PL tone on the output should be restored. In the meantime, make sure your radios aren’t requiring a PL tone from the machine, otherwise you won’t hear it.