QCII Decode simplex?

[TheAnka]

Our department's radio is having trouble alerting, and I feel it is due to interference from hearing the repeater which is now several miles away. (moved recently) The dispatch center is probably 100 yards from the fire station, and I thought we could just monitor the dispatch TX (repeater input) for the QCII tones.

For some reason, this doesn't seem to work. Any good reason anyone can think of? If you monitor the input frequency, you can plainly audibly hear the tones (a normal audio level, etc) but they will not set the alert in the radio.

In my initial test, I just changed the RX frequency in our GM300, leaving all the signaling set as is. After that failed, I tried from scratch to verify the correct RX and QCII tones, and it still failed.

Is there any reason why this wouldn't work? Also of note, the repeater requires a 100hz CTCSS, but I've tried leaving this on and off (CSQ) on the GM300 which listens for the QCII sequence.

Thanks for any suggestions.