Why a "dedicated" Trigger freq at LAPD
JoeyC said:
Not to hijack this thread, but I see the importance of an emergency trigger, and I've heard them go off in several systems, but why does LAPD have a special channel the radio switches to when this button is enabled? All others I've heard simply send the distress signal over the channel it's working on and it's handled accordingly there.
It's done either way in different systems. I think LASD also has a dedicated Trigger freq, 483.2875? Anyway, on some departments the triggered radio will stay on its current frequency, and other places it will go to a dedicated frequency (or talkgroup, in a trunked system).
LAPD decided on a dedicated frequency when they first went to UHF... it used to be 507.0875, but was moved to 507.2625 several years ago. The two main reasons were that sometimes a unit isn't on a dispatch-monitored frequency... they might be on a simplex or tac frequency, a detective channel, CLEMARS, anywhere. Send a "help" signal there and nobody but other people on that freq will hear anything... the indecipherable beeps and brrrps from your radio. At least until - and if - you are finally able to start talking.
Another advantage of a dedicated freq, at least the way it's set up at LAPD, is that the ofcr needing help gets immediate access to an RTO (dispatcher) who's not busy, on a frequency where nobody else will be talking over him/her. The RTO, whether its "his own" or someone else, gets the display of his unit number, and his last known location.
Depending on what's going on from moment to moment (such as "is the officer is able to talk?" and "is it best to bring other ofcrs into the 'conversation'?" or "does this ofcr need
uninterrupted uplink for himself, but his radio transmissions should go OUT - be "repeated" - on other freqs?"), they can multi-select any configuration of receive, transmit and/or patching of frequencies to best handle the incident as it unfolds.
Normally they will try to get everybody on to either their base (dispatch) frequency or a tac frequency as soon as it's practical, but it just depends on the situation.