My name is Matt. I have several M-series uhf motorola radios, and I'm having trouble with one of my MU21cv's. when I take the antenna out it sends and receives fine, but when I put an antenna in (that works just fine on other radio's) it won't receive but will still send. any thoughts or suggestions?
First, we recommend you do not press the PTT button with the antenna removed, as it can damage your radio's reference ocsillator (final amplifier). That being said, you have a unique problem which could be caused by a poor connection in the antenna port of the radio. It is possible screwing the antenna on is slightly separating the internal antenna connection from the component board, or you have a hairline crack in the board in that area.
Also, you may want to check the programming of your frequency and PL code. Sometimes in a close proximity radio will work with one another when set to a "near" setting. Never hurts to double check.
Best regards. Read More At : MU21CV UHF 2-Way Radio...