A common programming mistake: Radio doesn't always transmit

In my experience, the most common mistake technicians make when programming MOTOTRBO radios is not setting the Transmit Admit Criteria correctly in the channel.

Screenshot from the CPS showing the admit criteria in a digital channel.

The Admit Criteria selection Channel Free only allows the radio to transmit when when there is no signal whatsoever on the channel - this is quite a common configuration. However, there are some differences:

• Unlike analogue, if there is a signal present on the MOTOTRBO radios' receive frequency, the user will not notice it. In analogue radios, one could press the monitor button and hear whatever it was that was making the busy light flash.
• This signal could also be interference.
• The concept of squelch is different in MOTOTRBO radios. 
• -124dBm [or 0,141µV] (see above) represents a very weak signal.

The correct choice in this case, would be to increase the RSSI Threshold to a high - more realistic - value. Alternatively, try changing Admit Criteria to Color Code Free or Always.