Dekalb TRS: Unfamiliar activity on 40xxx talkgroups?

[leicanthrope]

I caught some of traffic on the Dekalb TRS using a bunch of unfamiliar talkgroups yesterday evening for a couple of hours. First I've heard anything on any 40xxx talkgroups, and I haven't seen any traffic there since. Curiously SDRTrunk didn't log associated radio IDs, but the traffic itself was crystal clear. Sounded like a fair bit of it was law enforcement. The one address mentioned that I was able to catch was here in Dunwoody.

40028
40074
40078
40090
40106
40110
40114
40118

Anyone have any idea what this might be?

 

[pdhall54]

I've never heard any 40XXX TG activity on Dekalb. all TG traffic so far has been in the 6XXX range. I'll log it this evening.

P25P1 855.712500 MHz, TG 6129 , DCFD TAC 4,2021-10-27-17:10:25,-98 dbm,1817, cc_freq mhz,RID 0,,P1,nco_off 0.0
P25P1 855.712500 MHz, TG 6129 , DCFD TAC 4,2021-10-27-17:10:26,-98 dbm,3626, cc_freq 854.61250000 mhz,RID 1060452,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6038 , DPD Dispatch,2021-10-27-17:10:29,-94 dbm,7897, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6038 , DPD Dispatch,2021-10-27-17:10:30,-94 dbm,8402, cc_freq 854.612500 mhz,RID 1081753,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6038 , DPD Dispatch,2021-10-27-17:10:33,-93 dbm,9786, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6038 , DPD Dispatch,2021-10-27-17:10:33,-92 dbm,10733, cc_freq 854.612500 mhz,RID 1253111,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6038 , DPD Dispatch,2021-10-27-17:10:35,-93 dbm,12353, cc_freq 854.612500 mhz,RID 1081753,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6038 , DPD Dispatch,2021-10-27-17:10:41,-92 dbm,24015, cc_freq 854.612500 mhz,RID 1253111,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6091 , DKSO Disp,2021-10-27-17:10:45,-95 dbm,25485, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6091 , DKSO Disp,2021-10-27-17:10:46,-96 dbm,28358, cc_freq 854.612500 mhz,RID 6003059,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6129 , DCFD TAC 4,2021-10-27-17:10:49,-94 dbm,30642, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6129 , DCFD TAC 4,2021-10-27-17:10:50,-92 dbm,32463, cc_freq 854.612500 mhz,RID 1060337,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6122 , DCFD 2 OPS,2021-10-27-17:10:56,-95 dbm,44680, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6122 , DCFD 2 OPS,2021-10-27-17:10:57,-96 dbm,47162, cc_freq 854.612500 mhz,RID 6003048,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6122 , DCFD 2 OPS,2021-10-27-17:10:57,-96 dbm,47508, cc_freq 854.612500 mhz,RID 1060849,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6122 , DCFD 2 OPS,2021-10-27-17:11:00,-96 dbm,50906, cc_freq 854.612500 mhz,RID 6003048,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6122 , DCFD 2 OPS,2021-10-27-17:11:04,-97 dbm,58231, cc_freq 854.612500 mhz,RID 1060851,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6122 , DCFD 2 OPS,2021-10-27-17:11:17,-95 dbm,81866, cc_freq 854.612500 mhz,RID 6003048,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6038 , DPD Dispatch,2021-10-27-17:11:28,-95 dbm,104710, cc_freq 854.612500 mhz,RID 1253111,,P1,nco_off 0.0
P25P1 855.712500 MHz, TG 6096 , DKSO 7 Jail 1,2021-10-27-17:11:36,-101 dbm,106755, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 855.712500 MHz, TG 6096 , DKSO 7 Jail 1,2021-10-27-17:11:36,-100 dbm,107645, cc_freq 854.612500 mhz,RID 1070723,,P1,nco_off 0.0
P25P1 857.312500 MHz, TG 6009 , DKPD 5 Tucker,2021-10-27-17:11:43,-93 dbm,117681, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 857.312500 MHz, TG 6009 , DKPD 5 Tucker,2021-10-27-17:11:44,-95 dbm,120267, cc_freq 854.612500 mhz,RID 1139189,,P1,nco_off 0.0
P25P1 857.312500 MHz, TG 6009 , DKPD 5 Tucker,2021-10-27-17:11:49,-95 dbm,126783, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 857.312500 MHz, TG 6009 , DKPD 5 Tucker,2021-10-27-17:11:49,-95 dbm,129284, cc_freq 854.612500 mhz,RID 6003046,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6122 , DCFD 2 OPS,2021-10-27-17:11:53,-99 dbm,131302, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6122 , DCFD 2 OPS,2021-10-27-17:11:53,-99 dbm,131601, cc_freq 854.612500 mhz,RID 6003048,,P1,nco_off 0.0
P25P1 855.062500 MHz, TG 6096 , DKSO 7 Jail 1,2021-10-27-17:11:57,-104 dbm,137063, cc_freq 854.612500 mhz,RID 1070774,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6121 , DCFD 1 DISP,2021-10-27-17:12:01,-98 dbm,140165, cc_freq 854.612500 mhz,RID 0,,P1,nco_off 0.0
P25P1 856.012500 MHz, TG 6121 , DCFD 1 DISP,2021-10-27-17:12:01,-99 dbm,140669, cc_freq 854.612500 mhz,RID 1060770,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6097 , DKSO 8 Jail 2,2021-10-27-17:12:04,-97 dbm,142259, cc_freq 854.612500 mhz,RID 1070774,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6097 , DKSO 8 Jail 2,2021-10-27-17:12:07,-93 dbm,145203, cc_freq 854.612500 mhz,RID 1070723,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6097 , DKSO 8 Jail 2,2021-10-27-17:12:09,-94 dbm,148409, cc_freq 854.612500 mhz,RID 1070774,,P1,nco_off 0.0
P25P1 856.962500 MHz, TG 6097 , DKSO 8 Jail 2,2021-10-27-17:12:16,-93 dbm,161121, cc_freq 854.612500 mhz,RID 1070723,,P1,nco_off 0.0
P25P1 855.062500 MHz, TG 6097 , DKSO 8 Jail 2,2021-10-27-17:12:25,-97 dbm,173582, cc_freq 854.612500 mhz,RID 1070774,,P1,nco_off 0.0
P25P1 855.062500 MHz, TG 6097 , DKSO 8 Jail 2,2021-10-27-17:12:28,-100 dbm,178754, cc_freq 854.612500 mhz,RID 1070723,,P1,nco_off 0.0

 

[leicanthrope]

I've never heard any 40XXX TG activity on Dekalb. all TG traffic so far has been in the 6XXX range. I'll log it this evening.

I've gotten a couple of mic clicks on 40028 so far this evening, but nothing on the other talkgroups just yet.

(For that it's worth, there are some oddball outliers to the 6xxx. I hear radio techs / contractors doing Emergency Responder Radio Communications Systems (ERRCS) testing on 11113 periodically, and I've heard snippets that make me suspect that 11111 and 11112 might be similarly assigned as some sort of test talkgroups.)

 

[ggulbrandson]

11111 and 2 are Motorola service talkgroups and 3 is the talkgroup we use for IFC 510 testing, correct. Everything is in the 6xxx range in the system other than the 11xxx and 31xxx for interop.

 

[leicanthrope]

11111 and 2 are Motorola service talkgroups and 3 is the talkgroup we use for IFC 510 testing, correct. Everything is in the 6xxx range in the system other than the 11xxx and 31xxx for interop.

Thank you! I'm running an SDR setup and I've started increasing to suspect that my system is occasionally erroneously logging traffic from other trunked systems that occupy the same frequency spectrum real estate.

I've had some luck identifying some of talkgroups that weren't already listed on the RR page, but there's still a pile more that I'm working through that I haven't been able to nail down. It's nice to know which ones I can cross off the list.

 

[ggulbrandson]

If you got any questions, I (try) maintain a few of the Motorola systems. I'm not going to give you any information that you can't figure out on your own, obviously, but with SDRs these days you can listen to pretty much anyone and anything (without encryption). I ordered a LimeSDR last August and it's supposed to be coming the end of March, but I've played with a couple RTL-SDR dongles and they're handy in a pinch.

GG

 

[leicanthrope]

If you got any questions, I (try) maintain a few of the Motorola systems. I'm not going to give you any information that you can't figure out on your own, obviously, but with SDRs these days you can listen to pretty much anyone and anything (without encryption).

Even if nothing else, just being able to scratch off the better part of a year's worth of those oddball log entries that don't even belong in the system is huge. Mostly I've been logging talkgroups that aren't documented by others online in an Excel document, and trying to cross-reference contextual clues along with what I've been able to figure out as far as individual radio IDs. Most of the channels that I'm stumped on don't seem to be especially secret squirrel - generally just used too infrequently for me to sort out, along with a bunch that I haven't logged much more than an oddball mic click.

The first batch are the ones that I've more or less figured out:

6017 - Dekalb PD CSI apparently
6100 - jail related, likely Dekalb SO
6224 - Sanitation or landfill
6225 - Sanitation or landfill, quite active
6226 - Sanitation or landfill, quite active
6138 - Fire training
6141 - Fire training / academy
6170 - City of Atlanta to Dekalb Co link of some sort?
6171 - City of Atlanta to Dekalb Co link of some sort?
6172 - City of Atlanta to Dekalb Co link of some sort?

I've been working a number used Emory Hospital and/or Emory University as well. I presume they handle the allocations of their channels on their end. Can you confirm the range of talkgroups they're using? (I've logged them on talkgroups between 6286 and 6318.)

This second batch are the ones that I have much less info / context on. With a few of these, I'm not even sure if the traffic is related to the channels intended use, or if I caught someone trying to reach someone in the wrong place:

6024 - attempt to contact "Dekalb Homeland"
6028 - Doraville / Dunwoody PD units, usually involving traffic control
6033 - attempt to contact Tucker Burglary CID
6035 - This one seems to be all over the map: heard what seems to be Dekalb SO, calls for SVU detectives, animal control check ins, etc.
6037 - occasional radio checks, and nothing more
6073 - attempt to contact DA investigator
6074 - Probation units training?
6082 - Avondale Estates PD for special event, plus other agencies here and there
6084 - some sort of school
6102 - Dekalb marshals?
6123 - occasional fire / ems traffic
6157 - occasional fire / ems traffic
6159 - occasional radio checks
6160 - police interop?
6161 - Used to sound like school resource officers, now sounds like jail traffic??
6180 - occasional radio checks
6185 - Doraville PD?
6186 - Doraville?
6196 - LEO attempting to contact radio
6228 - water or sewer related
6233 - parks?
6254 - possible police callsigns
6259 - possible police

Finally the list of channels that I've heard keyed up or hot mic'ed with no usable context. With this list, anything would be helpful. Are there any that you can confirm to be red herrings?

6016
6019
6025
6071
6072
6075
6081
6099
6119
6125
6135
6136
6140
6155
6156
6158
6179
6181
6187
6244
6245
6250
6251
6253
6260
6263
6264
6330
6332
6333
6338
6355