Posted on 08/08/2003 10:46:55 AM PDT by lainie
ATTENTION
Big doins right now on high desert ATAC. They're surrounding a house in the vicinity of 200 ST E and AVE R.
"be advised we've got no cover and are sitting ducks if he's scoping us.."
"we need more units!"
They're surprising the location.
Sounds like they might think they got him, getting SB involved.
Air ship on scene.
There is also "tranmitter fingerprinting" but it requires a long set up and more equipment than you will find in the field.
Now let's grab this guy.
I am starting to wonder if they were talking about mdt's, ACK'S are message acknowledgements mdt's get when they send a message, or change state, (on-off or what ever).
It depends on the system. LASO's move to 480 mhz is fairly recent, so they most likely have the identifiers built in. They're a little digital tone generator that sends a serial number identifying the radio number any time you key the mike. The dispatch system maintains a database cross-referencing radio serial number and unit number on an ongoing basis.
With respect to the question about the absence of identifying information on the audio feed we're getting, the system is a type known as "repeater duplex", with the cars on one frequency and the dispatcher on another. The car radios are picked up and rebroadcast on the base frequency, and in the process the little "identifier squawk" is cut out. If we were listening directly to the units, I suspect we'd be hearing it.
Even though it's called a TAC frequency, it's repeater duplex, thus the confusion among the troops. LAPD's system allows "direct" communication without triggering the repeater, and in that mode you can hear the "squawk". LASO probably has something similar. and they may be using it along with cell phones in addition to the more publicly accessable communications.
If he has the deputy's radio, it probably has the local TAC frequencies programmed in, but it was most likely tuned to the Antellope Valley base frequency. So, I guess we can look at the guy's picture and try to figure out whether's he's bright enough to switch frequencies.
480 band, it should be 3mhz higher. However, it's line of sight, so unless you're in the immediate vicinity all you'll hear is a faint carrier and a lot of noise. We're probably better off on the base.
Come to think of it, that LAPD "direct" mode works by switching the car transmitter to the base frequency. Capture effect results in the base being able to override it when needed.
By the way, we can hear the beeps from the scanner as it's programmed, it's become famous!!!
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