televiper75
Member
Hearing Henderson Co. SO doing what sounds like inter-agency ops on TG: 51664 - seems to be relays to the EMS dispatcher.
2012-2014 VIPER Discussion (Archive)
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Drafin
Member
Hearing storm related traffic on TGID 10128. Sounds like Burke Co. EMS. Maybe an admin channel. Not 100% sure though.
Draf
Draf
That's an impressive ear you have on you.
Great catch. Added it to the database.
Happy Monitoring
Marshall KE4ZNR
randyK
Member
Heard some type of surveillance operation on TG #10368, anyone have any ideas?
Drafin
Member
Not really, just some command type guys talking about where EMS units were going and what crews and then I recognized some street names.
Draf
Chris:
That makes sense as I live in the troop B district. However, can you please explain what is a "added status bit" and how does this differentiate from the "Troop B Mutual Aid" at TGID# 560?
Thanks for your response and explanation in advance?
That makes sense as I live in the troop B district. However, can you please explain what is a "added status bit" and how does this differentiate from the "Troop B Mutual Aid" at TGID# 560?
Thanks for your response and explanation in advance?
Standard talkgroups are spaced out in multiples of 16 for Type II trunked systems. If a talkgroup is altered for a patch, multiselect, encryption, emergency, etc, then a status bit is added. In this case...it doesn't make sense unless there's a chance you misread or your scanner didn't decode the status bit properly.
This time, you would notice that it's a status bit of +8, which per the link below, means DES encryption is utilized. This isn't the case though, because you were able to hear the conversation. Do a little reading on the link below and that might explain things better.
Motorola Type II - Wikipedia, the free encyclopedia
What kind of scanner are you using? Some scanners have the ability to ignore the status bit so regardless of the alteration, it still displays the original/base talkgroup.
This time, you would notice that it's a status bit of +8, which per the link below, means DES encryption is utilized. This isn't the case though, because you were able to hear the conversation. Do a little reading on the link below and that might explain things better.
Motorola Type II - Wikipedia, the free encyclopedia
What kind of scanner are you using? Some scanners have the ability to ignore the status bit so regardless of the alteration, it still displays the original/base talkgroup.
I'm positive that I was reading the number correctly plus I saw per my personal description of the system that it was coming from Viper.
I am using a Uniden BCD396XT scanner, that i am still learning day-by-day. The Wikipedia article was very interesting and I have it bookmarked for further advanced reading
CFP387
Member
When monitoring the Rowan County VIPER site on my trusty BC246T (analog of course), in the search mode I get a LOT of what sounds like control channel noise on various talk groups. Is this going to be a routine thing until the switch to digital?
What you are hearing are the digital voice talkgroups. The 246t can't decode the 1s & 0s
that make up the digital voice talkgroup vocoder so it just passes it along as "noise".
That's the big difference between analog only scanners like the 246t/346XT and the digital voice capable 396XT. The 396XT has a digital voice vocoder that can convert/decode that stream of 1s and 0s digital "noise" to digital voice that we can understand.
And the switch to digital voice talkgroups for all users is well underway so you will start
to see fewer and fewer analog users that can be monitored on the 246t.
Marshall KE4ZNR
randyK
Member
Caught another surveillance op on TG #3984 digital, didn't sound like SHP training, radio IDs also affiliated with TG #3968, Any ideas Marshall? Thanks
ALE. I have updated the database to reflect the
changes. Thanks for keeping me on my toes!
Marshall KE4ZNR
CFP387
Member
Thanks Marshall! The one thing that confuses me though is that the display is showing the talkgroups in even numbers multiple of 16. Is that just all the scanner knows to default to or what?
Ahhh yes.
The ol' pesky Status Bits. In a Moto 3600 Baud trunked system you gotta have room in between TGIDs for Status Bits.
Dec ID + # 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
So that it is why if you have "Status Bit: Yes" Turned on in your scanner you might see 2711 for SHP Troop E Dist 3. That would be the Base TGID 2704 plus 7 status bit which would indicate a Dispatcher initiated Multiselect.
You will find that the SHP Dispatchers use Multiselect a heck of a lot because the 1 dispatcher wants to dispatch out to multiple districts at once. And general rule of thumb is that whichever TG is picked first in the multiselect is the one that will have the "plus seven" Status Bit. So Lets say SHP Dispatcher wishes to broadcast over SHP Troop E Districts 1,2, 5 all at once. SHP Dispatcher first selects Dist 2 TG (2672) then adds Dists 1 (2640) and then Dist 5 (2768) to the Multiselect. Since the Dist 2 TG 2672 was chosen first then it would be the TG to have the +7 Status Bit. So with status bit enabled in our scanner we could expect to hear the multiselect on TG 2679 which is the 2672 Base TG + 7 for the Multiselect.
Something else nifty: Look in the RR database at the Hex value for SHP E Dist 2: 0A7.
Take that and add 7 to the end for the multiselect status bit. So now we have 0A77.
Go to windows calculator and select "advanced". Select Hex Mode and enter 0A77. Now select convert to decimal and presto chango! We have Decimal ID of 2679! Remember that TGID?
For VIPER (or any Moto 3600 Baud System) you can take any hex TGID add the status bit to the end and convert it to decimal and it will show you the Base TG plus Status bit.
Just goes to show you that there are many reasons why we list the Hex TGIDs in the database here at RR.com
Marshall KE4ZNR
And another awesome break down of information, from Marshall. Sorry its off topic but hey give credit where credit is due.:lol:
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