In Reply to: Re: Lots of traffic on 62928 posted by The Big O on November 01, 2000 at 18:54:11:
: Thanks for the info. Apparently Guardian 1 also has the equipment, and dispatchs were also on 62928,responding that certain areas were "cold".
: :
: : : Lots of traffic on 62928, pursuing a bank robbery suspect.
: : : Lots of refrence to "3 to 4 bars", "10 bars", anyone know what this means?
: : Some PD's vehicles are equipped with a detection/direction finding unit mounted in the car that picks up the signal from a radio transmitter sewn into a bank bag. When a robbery occurs at a bank and the teller places the money into one of these bags, and the robber exits the bank the transmitter is activated. It allows PD units to locate the general area of the bags location. Bars indicate strength of signal and they can also tell which direction the signal is coming from i.e; east west.....They have handheld units for more precise directional info.
This TG is PSOPS N1. Avid PD fans will want to watch this one. Also, for SPD, watch SPD All Call, 3216 (050-1 for us Type I listeners) There are three others, PSOPS S1, S2, and N2. Most TG lists show these. Watch them all, but you will see most on N1. Oh, and watch PSAP Regional Shared, TG 62800 (785-1 Type I) This is used between the various agency dispatchers (Public Safety Answering Points) Mostly radio checks, but occasionally a description of a just committed crime where suspects are on the loose.
Seattle PD calls this "PDT". The system they are using, as described in previous posts, allows banks (they call them "institutions" on the air) can "subscribe" to the system. Using doppler receivers in cars, and fixed receivers throughout the area, mobile units can follow, and triangulate, on a signal received from a transmitter placed with the money. Don't know if it's in a fake wad o' bills, or sewn in the money bag, won't take the gamble either :^)
Dispatchers can see a signal come on the air from a fixed site, usually named for the area served (wedgewood, greenwood, lake city, south park, are some known sites that come to mind) When a dispatcher sees this, (I'm referring mostly to SPD) they dispatch a "priority alarm" on the all call channel, which by the way, is refferred to in most TG lists as "air to ground" Go figure, it's supposed to mean "All Talk Groups"
So the dispatcher calls a priority alarm on 3216, telling them "follow up on PSOPS N1" The dispatcher can command units to this TG, and used to most of the time, but nowadays the officers seem to switch themselves. All cars equipped with PDT tracking equipment, regardless of sector assignment, usually respond to a Priority Alarm. The units in the area will respond to the scene / area to secure the area, and begin to track it down. PDT units from other areas of town (usually) take up fixed positions in strategic areas that allow them to either get a fix on the signal, being another point of triangulation, and also allows them to pick up the signal if the bad guy heads their way.
From what I have gleaned listening the last year and a half or so, there are a fair amount of false trips, which they respond to as a normal incident. Falses can be generated if a "subscribing" "institution" mishandles a transmitting unit, and I also believe some of them have been just plain phantom type stuff, the fixed receiver saw a signal. These units appear to transmit a simple carrier, as they do not seem to have a way to identify the individual transmitters by any sort of ID (e.g. Lo-jack)
I will say this, SPD has become VERY adept at responding to these. Not that I ever wanted to, but I DEFINATELY would not be robbin' banks 'round here, knowing how fast they can find one (bankrobber, that is).
Portland Police Bureau, in the early 90's, boasted of tracking a bank robber to capture 9.5 minutes after receipt of the first trip, with NO intial known direction of travel.