ICE MotoTRBO TRS Decoding Project

A forum for discussion of the many trunked radio systems in and around our listening area.
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Scott
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ICE MotoTRBO TRS Decoding Project

#1 Post by Scott » 02 Jan 2013 11:37

Decided to run UniTrunker on the 712c 900 MHz trunked system in the background this morning while at work, using one of my RTL2832U USB sticks. I listened prior to firing up UniTrunker and thought that the control channel on 936.5125 sounded a little weird. When I ran UniTrunker I received no data. Listening again, it sounded suspiciously like a MotoTrbo signal, so I ran DSD and sure enough there was the DMR/MotoTrbo data stream with voice communications on one of the slots.

I'm watching 2 MHz of spectrum with the RTL2832U as I decode with DSD but not seeing much in the way of any other signals for this same system.

I'm also decoding a signal on 937.6875. All I see in the Wiki for that is an ICE system in York, ME. Considering that I'm using the RTL2832U and the remains of a scantenna mounted on the tower here, I doubt that's what I'm seeing. 937.6875 is/was also part of an LTR system here on the Cape. I see in the Wiki that the frequency listed indicates a "constant stream" that may be GPS related. If this is the same stream it is most certainly MotoTrbo.

I'll continue to monitor. It's great to be able to dedicate a $16 item to this type of project. :)
Scott

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#2 Post by Scott » 02 Jan 2013 12:08

Trying to get this sorted out, it's a little confusing!

Steady Datastreams
936.5125
937.6875
938.1250
All contain period voice communications.

Occasional Datastreams
935.0125
936.7125
938.1125
939.6250
All have confirmed voice traffic, and only seem to be active when voice traffic is present.
Scott

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#3 Post by Scott » 02 Jan 2013 12:25

Considerable FCC licensing confusion as well...I'm missing something or it appears that none of these are currently licensed for the MotoTrbo designator. Some of the above frequencies don't seem to show up at all in FCC searches, yet they do from RR's FCC database, some to ICE TRS in Worcester.
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#4 Post by Scott » 02 Jan 2013 14:27

As I continue to monitor various frequencies as mentioned I'm hearing a great deal of "off-Cape" traffic. I'm not sure how these new systems work but they are apparently networked together in some aspect. Why I would be hearing traffic from the Stoneham area down here is beyond me, though. Also heard some references to Quincy and to "Brighams" which I'd guess might be Brigham and Women's Hospital. Definitely a good deal of private ambulance traffic. At the same time I'm hearing Cape Cod references as well. Of course I'm jumping around to different frequencies as mentioned in an earlier post, which is likely complicating things.

DSD does not allow for the identification of talkgroups and/or individual radios when decoding MotoTrbo, so no way to even begin to see who's who here right now. There is a program out there called DMR Decode that might lend an idea, but the compromise is that it just looks at the data stream; no voice decode. On the plus side if I can get it working I can run another RTL2832U stick in a separate window using SDRSharp and DSD and maybe start putting some things together.
Scott

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#5 Post by ecps92 » 02 Jan 2013 14:43

It might give you some info as to the SysID / Tower and Adjacent Towers

I have noticed in researching some of the Maine [Analog] ICE TRS that licenses do not appear in the FCC either.
Not even checking the Expired

From reading their Literature on the web, the TRBO can be linked/patch vs having to switch zones manually
Scott SNE Webmaster wrote:As I continue to monitor various frequencies as mentioned I'm hearing a great deal of "off-Cape" traffic. I'm not sure how these new systems work but they are apparently networked together in some aspect. Why I would be hearing traffic from the Stoneham area down here is beyond me, though. Also heard some references to Quincy and to "Brighams" which I'd guess might be Brigham and Women's Hospital. Definitely a good deal of private ambulance traffic. At the same time I'm hearing Cape Cod references as well. Of course I'm jumping around to different frequencies as mentioned in an earlier post, which is likely complicating things.

DSD does not allow for the identification of talkgroups and/or individual radios when decoding MotoTrbo, so no way to even begin to see who's who here right now. There is a program out there called DMR Decode that might lend an idea, but the compromise is that it just looks at the data stream; no voice decode. On the plus side if I can get it working I can run another RTL2832U stick in a separate window using SDRSharp and DSD and maybe start putting some things together.
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#6 Post by jwb8734 » 02 Jan 2013 16:44

Scott - I'm curious how you have this set up you put in the USB Hardware but how does it decode?

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#7 Post by MrSvenSven » 02 Jan 2013 17:23

Scott SNE Webmaster wrote:ICE TRS in Worcester.
A search of the NEFD isn't coming up with anything, what are you seeing that is in Worcester?

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#8 Post by Scott » 02 Jan 2013 17:26

jwb8734 wrote:Scott - I'm curious how you have this set up you put in the USB Hardware but how does it decode?
Hi John,

The RTL2832U is controlled via the SDRSharp software. Virtual Audio Cable also must be installed. Under the Audio Output of SDRSharp the selected device is Virtual Audio Cable. Under the Windows recording device properties, Virtual Audio Cable MUST be the default recording device. Finally, DSD for Windows is run in a command prompt window. Balance the audio in SDRSharp for best decode.
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#9 Post by Scott » 02 Jan 2013 17:26

MrSvenSven wrote:A search of the NEFD isn't coming up with anything, what are you seeing that is in Worcester?
I ran a few of the frequencies in the Radio Reference database and they pointed to ICE in Worcester.
Scott

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#10 Post by jwb8734 » 02 Jan 2013 17:33

Scott SNE Webmaster wrote:Hi John,

The RTL2832U is controlled via the SDRSharp software. Virtual Audio Cable also must be installed. Under the Audio Output of SDRSharp the selected device is Virtual Audio Cable. Under the Windows recording device properties, Virtual Audio Cable MUST be the default recording device. Finally, DSD for Windows is run in a command prompt window. Balance the audio in SDRSharp for best decode.
Ok Now I know how you were getting the audio transfered.
I guess I need to get myself one of these.

I should be getting my VHF Hytera DMR radio in soon so I want to see what I can do to make sure it works.

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#11 Post by Scott » 02 Jan 2013 19:00

jwb8734 wrote:Ok Now I know how you were getting the audio transfered.
I guess I need to get myself one of these.
I should be getting my VHF Hytera DMR radio in soon so I want to see what I can do to make sure it works.
If not just for this purpose, for many others. Amazing little devices that do a lot for short money. I'm up to 6 of them now. Make sure you get the one with the R820T chipset though, it is a better performer and no DC spike at the center of the display.

But back on topic completely...I'm not finding any additional activity down here at this point; of course much of this revolves around business comms that predominantly would be active during business hours. Still hearing some activity on 936.5125 right now with its constant stream.
Scott

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#12 Post by MrSvenSven » 02 Jan 2013 19:14

Scott, can you provide any audio samples of the TRBO control channels? A quick search of the 900 band reveals some data on ICE frequencies up my way as well.

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#13 Post by Scott » 02 Jan 2013 19:22

MrSvenSven wrote:Scott, can you provide any audio samples of the TRBO control channels? A quick search of the 900 band reveals some data on ICE frequencies up my way as well.
That's something I want to have the capability of doing...I just need to think of what I need to do to accomplish it. I have fed Trbo from this setup to feeds in the past, notably the Falmouth Road Race operations last summer, so I should be able to dump it to an audio file. Just need to think about it for a minute. I'm probably thinking too hard. Headed out for a bit but I'll revisit it when I come back.
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#14 Post by MrSvenSven » 02 Jan 2013 19:24

Scott SNE Webmaster wrote:That's something I want to have the capability of doing...I just need to think of what I need to do to accomplish it. I have fed Trbo from this setup to feeds in the past, notably the Falmouth Road Race operations last summer, so I should be able to dump it to an audio file. Just need to think about it for a minute. I'm probably thinking too hard. Headed out for a bit but I'll revisit it when I come back.
http://www.kb9ukd.com/digital/TRBO.mp3

What I am hearing does not sound like that, but I would expect a trunked control channel to sound different than conventional voice.

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#15 Post by MrSvenSven » 02 Jan 2013 19:51

Do your "occasional data" channels sound like the mp3 I linked to in the previous post? I think that's what I have found up here.

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#16 Post by Scott » 02 Jan 2013 20:25

More or less, yes. The "control channel" does sound a bit different, and it is displaying "CSBK" in the idle stream, which is apparently an indication of a "Connect Plus" system from what I'm reading at RR and a few other places.
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900MHZ TRBO systems in Worcester Coutny

#17 Post by MrSvenSven » 02 Jan 2013 20:45

I believe I have found a couple TRBO systems:

The first isn't licensed so I'm not sure where it is, but on 936.5875 I have a control channel in slot 1 and voice in slot 2.

The second uses frequencies that were at one point part of the ICE analog trunk in Upton, so I assume these are part of a new TRBO trunk at the same location.
937.25 Control/voice
937.7375 voice

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#18 Post by Scott » 02 Jan 2013 20:47

Are you seeing them as slot1 and slot2? I've only ever seen slot0 and slot1 when running DSD....or are you running DMRDecode, which I can't get to run at all on ANY of my PC's...I'm obviously missing something.
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#19 Post by MrSvenSven » 02 Jan 2013 20:51

Scott SNE Webmaster wrote:Are you seeing them as slot1 and slot2? I've only ever seen slot0 and slot1 when running DSD....or are you running DMRDecode, which I can't get to run at all on ANY of my PC's...I'm obviously missing something.
You're right, it's slot 0 and 1

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#20 Post by Scott » 02 Jan 2013 21:15

Of the three control channels I see here, the strongest clearly is 938.125. 936.5125 is the second strongest, and 937.6875 is the weakest of the three but still quite strong. Each is showing CSBK one one of the slots, and Slot idle on the other. On the 936.5125 I heard a station identifying as "268" being called by mobiles ID'd by numbers, one of which was "24". Not overly clear on what the traffic is pertinent to yet as transmissions have been few and far between. Not sure if that rings a bell with anyone but from what I heard earlier today it could be anywhere if these sites are networked.
Scott

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#21 Post by disp617 » 02 Jan 2013 23:14

My findings from Leicester tonight with DMR
network 139 site 7 939.1875 seems to be constant control channel and fairly strong
network 134 site 21 937.2500 I think is upton
network 134 site 21 937.7375 I think is upton. group 46 has shown activity
network 134 site 13 936.6000
network 134 site 13 936.5875

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#22 Post by disp617 » 02 Jan 2013 23:18

Scott SNE Webmaster wrote:Considerable FCC licensing confusion as well...I'm missing something or it appears that none of these are currently licensed for the MotoTrbo designator. Some of the above frequencies don't seem to show up at all in FCC searches, yet they do from RR's FCC database, some to ICE TRS in Worcester.
no ICE site in the Woo. They have their own tower on Asnebumskit ib Paxton. Thats where the Analog site is

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#23 Post by Scott » 03 Jan 2013 08:19

The info at RR is apparently in error then. In any event, I'll try to dig into this a bit more today if possible.
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#24 Post by Scott » 03 Jan 2013 08:57

Success with DMRDecode...and one of the beauties of this is that DMRDecode and DSD will run together off of the same data source without issue. This should afford the eventual possible identification of "talkgroups" on these systems. Thus far today I show the following:

935.0125 - "Connect Plus" (Network 134) (Site 12)
937.6875 - "Connect Plus" (Network 139) (Site 5)
938.1125 - "Connect Plus" (Network 134) (Site 11)

So we do have rotating CC's. Also, DMRDecode as stated does show Group calls. I'm seeing a Group 43 on Site 12 being called by various radios. On DMRDecode you can see the radio ID change with the transmissions.
Scott

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#25 Post by N1BHH (Silent Key) » 03 Jan 2013 08:59

Many people put Paxton and Worcester together because they are neighbors. And the listing does show Paxton as the location unless I'm missing something there.
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