Cause: The SafeCom remote is not receiving RF transmissions from the SafeCom receiver. Normally, when the SafeCom remote transmits a poll, the SafeCom receiver receives the poll and does not transmit an of ACK (acknowledgement) back to the remote; Polls from the remotes are essentially one-way. When the SafeCom remote transmits an actual event, the SafeCom receiver receives the event and transmits a ACK back to the remote to confirm reception of the event. The remote receives that ACK, and in turn transmits another ACK to the receiver to confirm reception of the original ACK. If the remote can transmit RF but not receive, it will transmit an event successfully; However, since the remote cannot hear the ACK for that event from the receiver, it never sends an ACK to confirm the receiver’s ACK transmission. This results in an RF Trouble indication at the SafeCom receiver.
There is a problem with the RF signal path. The most common causes are problems with the antenna or feedline.
- The coax cable may have taken on water
- The customer may have incorrectly modified the feedline
- There may be a major physical obstruction between the remote and the tower
Have them attempt to poll the remote. It probably won’t pass the poll. Remember, proper installation requires a 10db margin test on installation
