The Westchester Trunking Rogue Talkgroup Thread

[unleashedff248 3]

I figured I'd start posting some new talkgroups I head on the system while in ID Search mode. Got three so far:

17648: No voice heard, but falls in the Fire/EMS talkgroup numbers

50487: Seems to be transit...annoying

7: I have no idea

Anyone else got some?

[DOC22 1]

I figured I'd start posting some new talkgroups I head on the system while in ID Search mode. Got three so far:

17648: No voice heard, but falls in the Fire/EMS talkgroup numbers

50487: Seems to be transit...annoying

7: I have no idea

Anyone else got some?

17648 is the talkgroup for 60 EMS 13, 50480 is Bee Line Busses, while 50487 doesn't appear in the list I have, it may be a new group., and 7????? No Idea on that one.

[SteveOFD 176]

Talkgroup ID's 7 and 50487 are not valid TG numbers. Talkgroup numbers end in even numbers, and all TG's are sixteen digits apart. For more info see Wikipedia - Talkgroups. With the spacing between TG's being sixteen, valid TG's will be divisable by sixteen.

Edited February 26, 2008 by SteveOFD

[DaRock98 76]

I have a questions it might have been answered already but I can't seem to find it. In order to hear the whole conversation do you need to have the bee line bus talkgroups programed in? I did not program them into my scanner and I seem to be only getting half of a convo. If not, do you have any suggestions as to why this is happening?

[SteveOFD 176]

DaRock98, you do not need to program the BeeLine buses to hear Fire/EMS Talkgroups. Do you have the scanner, and banks, programmed for trunked operation. If it is in conventional mode you may hear the first part of the conversation, but if the return part is on another frequency you may be missing that part.

Check out this previous thread for further info. There is alot there, but there was alot of info posted during the thread.

[DaRock98 76]

Ok thanks I think I figured it out just waiting to hear someone talk now!

[DaRock98 76]

ok sorry 1 more thing I hear talking but its from the buses is there a way I could not listen to the buses and only hear fire/ems??

[jack10562 414]

You either have to lock out or delete the transit talkgroup bank, and set the trunking mode to (closed) ID SCAN

If you have it in (open) ID SEARCH mode, it will still pick up any talkgroup in the system.

[DaRock98 76]

You either have to lock out or delete the transit talkgroup bank, and set the trunking mode to (closed) ID SCAN

If you have it in (open) ID SEARCH mode, it will still pick up any talkgroup in the system.

Ok thank you I will try to delete them b/c I had it closed and I was only hearing part of a conversation now that its open I hear everything but also get the buses.

[unleashedff248 3]

Talkgroup ID's 7 and 50487 are not valid TG numbers. Talkgroup numbers end in even numbers, and all TG's are sixteen digits apart. For more info see Wikipedia - Talkgroups. With the spacing between TG's being sixteen, valid TG's will be divisable by sixteen.

Not exactly true. If the talkgroup is 1 higher than the desired talkgroup (ex: 33553 instead of 33552), it is because a dispatcher has selected the all talkgroup (ATG) mode. All radios are programmed with an ATG talkgroup. When an ATG is selected, all radios who have that talkgroup as their ATG automatically tune to that talkgroup while the dispatcher is transmitting. This is used for broadcasts from dispatch for all the units. Our ATG is 1616 in decimal or 065 in hex. It is not selectable on the radio the way it is programmed. I have my personal radio programmed with it in and during active incidents, this talkgroup will have all comms for that incident on it.

If the reported talkgroup is 2 higher than the desired talkgroup (ex: 34002 instead of 34000), it is because a user has pushed the emergency button on the radio. If this button is pressed, a voice channel is allocated exclusively for the talkgroup that the radio is currently tuned to with an offset of 2.

If the reported talkgroup is 3 higher than the desired talkgroup (ex: 34003 instead of 34000), it is because a dispatcher has patched two or more talkgroups together. Users on any of the patched talkgroups may talk to each other during the duration of the patch.

If the reported talkgroup is 8 or more higher than the desired talkgroup (ex: 34352 instead of 35344), you probably are also hearing noise, as this is an indication that you are listening to a digital talkgroup. The Westchester County system has no digital (P25) talkgroups as far as I know, although our radios ARE digital capable.

With that in mind, here's some more:

50800:

49751: ATG?

50418:

50544:

50400:

50423: Heard Liberty Control answering units

49776:

50036:

50384:

52728:

52976:

50426:

54128: Traffic reports from "Liberty Control"

52080:

Seems most of the unknown TG's fall within the transit scheme. Some of these I heard myself, other were just recorded by a software program, including the previously mentioned TG of 7. This was when the system first came online and before any radios were even installed on the system. I'd imagine it's just a test talkgroup or something. I'd be interested to see more fire/ems talkgroups come online, such as a Admin talkgroup for county coordinators/cars or even a radio tech talkgroup, which probably already exists somewhere.

[SteveOFD 176]

unleashedff248 is correct in that TG's numbering can be any digit. Standard TG's have sixteen digits between them, and are divisible by sixteen.

From the RadioReference - Wiki:

Type II Special Status Bits

Type II Smartnet systems use these status bits for special transmissions such as Emergency, Patches, DES/DVP scrambled transmissions, and Multiselects on Motorola Trunking systems. Motorola Trunking radios directly interpret them for their special functions, thus no difference is noticed by the person with the radio. The Trunktracker scanners however interpret these special talkgroup status bits as different talkgroups entirely. Below is the conversion chart for these special status bits.

TTID + # Usage ID+0 Normal Talkgroup

ID+1 All Talkgroup

ID+2 Emergency

ID+3 talkgroup patch to another

ID+4 Emergency Patch

ID+5 Emergency multi-group

ID+6 Not assigned

ID+7 Multi-select (initiated by dispatcher)

ID+8 DES Encryption talkgroup

ID+9 DES All Talkgroup

ID+10 DES Emergency

ID+11 DES Talkgroup patch

ID+12 DES Emergency Patch

ID+13 DES Emergency multi-group

ID+14 Not assigned

ID+15 Multi-select DES TG

Therefore, if a user was transmitting a multi-select call on talkgroup 1808, the trunktracker would actually receive those transmissions on 1815. Some common uses of these status bits are as follows: When a user hits their emergency button, all conversations on the talkgroup revert to the Emergency status talkgroup (ID+2) until the dispatch clears the emergency status. Therefore, if someone hit their emergency button and their radio was on talkgroup 16, all communications would switch to talkgroup 18. A lot of Fire and EMS departments dispatch tone-outs and alarms as Multi-select communications (ID+7). Therefore, if your fire department dispatch talkgroup is 1616, and they do dispatch tone-outs and alarms as Multi-selects, then those communications will be on talkgroup 1623. This could be a problem, because you will miss communications if you don't have those talkgroups programmed, or your scanner in search mode.

Retrieved from "http://wiki.radioreference.com/index.php/Motorola_Talkgroups"

[Guest 40-32 Comms]

...From the RadioReference - Wiki:...

...This could be a problem, because you will miss communications if you don't have those talkgroups programmed, or your scanner in search mode.

Retrieved from "http://wiki.radioreference.com/index.php/Motorola_Talkgroups"...

Without getting too far into the arcane minutiae of Type II data streams, it is correct to say that the valid talk group numbers are all even numbers in increments of sixteen. The last hex place in a TGID is technically a status bit, and not a separate talk group. You do not actually have to enter all possible variations of the ID to receive the various call formats on a scanner. If you simply enable the “Ignore Status Bit” option, the scanner will treat and display all talk group activity as if it occurred on the “base” TGID / status bit.