DMR CC in Jackson Co

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plutonium233

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Hi,

I recently set up a RTL-SDR, and I have been exploring the spectrum looking for new things to monitor. Well, I've been able to hear several TRS's in the area of Jackson county which I have been able to follow using Unitrunker and SDR#. I recently came across what appears to be a control channel on 451.0375, but I haven't been able to figure out what it is, using the database. Unitrunker is telling me it is a DMR system, but I don't know with 100% certainty. I have a good strong signal from what I can tell, and I've tried using DSD+ for decoding voice. So far, I haven't heard any transmissions (nor have I seen the software leave the parked position). Any ideas on what this might be?
 

milf

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Its the ComSouth DMR in Biloxi. ComSouth is building an State Wide DMR network, based off thier old LTR TRS's, and with several new sites.


WQON780
451.0375
451.1125
451.2125
451.4750

Emissions Designators: 11K0F3E (Analog Narrowband FM) 7K60FXE and 7K60FXD (DMR TDMA 2 Slot)

MotoTRBO

And again I call for monitoring of ALL the ComSouth sites statewide to confirm they have switched over to MotoTRBO for the whole network. I wish there was a way to get the full system data for DMR TRS's set up as Wide Area TRS... Then I could set the full system up in the DB.... I will add this TRS asap.
 

milf

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OK, if you have DMRDecode, and get a chance, run it on this system, and tell us the Site Number, SYSID, etc. And DSD+ should give you the CC's and Slot Numbering.... Once I have this data, I will build it in the Db and we can start mapping this baby out.
 

plutonium233

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Sorry that I haven't been back sooner. Unfortunately, I am unable to get the DMRDecode software running on my computer. I am getting an error code "Could not find the main class: com.dmr.DMRDecode." It sounds as if I am missing some sort of dependancy. Any ideas?
 

milf

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Looks like your dl of the software was glitched... Might want to ask in the Digital forums about what the problem may be and possible fixes. Could be as simple as a new dl and install..

I will be re tapping my 92 soon, and will also be trying out the DMR softwares as there are a few systems I want to look into here in INDY.
 

plutonium233

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I was able to get DMRDecode running, and I captured a short log file of the activity. To be honest, I'm like a pig staring at a wristwatch here. I'm not even sure what all this data means. How can I get this file to you so you can see if it is useful? Otherwise, could you tell me specifically what you need from the data?
 

plutonium233

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Just to see what happened, I fired up DSD+ and noticed that I had much fewer errors as the data was scrolling by. This got me thinking about the settings so I went back in and un-inverted the signal which yielded better results (see attached). Let me know if I'm on the right track. In the mean time, I'll sit back and await further instruction.
 

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KE5TLF

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As suggested you should probably seek help in the Digital Voice Decoding forum at this point. The "real" experts probably don't look here often, if ever.

If you want some more DMR to play with, Ingalls is now all DMR conventional, as well as BP, and some or all of Gulf LNG. Also Ocean Springs DPW has been using TRBO for several years too.

Might try looking at all the casinos and see if any of them are using DMR too.
 

EricCottrell

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Just to see what happened, I fired up DSD+ and noticed that I had much fewer errors as the data was scrolling by. This got me thinking about the settings so I went back in and un-inverted the signal which yielded better results (see attached). Let me know if I'm on the right track. In the mean time, I'll sit back and await further instruction.
Hello,

DMR data frames use a sync pattern that is inverted from the voice frame sync pattern. The result is a control channel will look like a continuous garbled voice transmission if the signal is inverted. It appears to be the case when you are using DSD+.

I thought DSD+ automatically detected this, but look to see if there is a -xr switch to invert the DMR signal.

73 Eric
 

plutonium233

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Eric, thanks for that information. This is the first time I've dealt with DMR.

I would have asked for help in the Digital Voice Decoding forum, but I didn't know I needed any (I managed to figure out how to get DMRDecode running). I just wanted to know if this is the information MILF was looking for. That being said, I probably could have taken a closer look at the logs and figured this out.

Site Number: 13
SLCO: 10
Network: 175

This is from the data below:

4:02:27 PM DMR Data Frame (BS)
CACH : TACT AT=1 Ch 2 Continuation fragment of LC
Slot Type : Colour Code 1 Idle
4:02:27 PM DMR Data Frame (BS)
CACH : TACT Ch 1 Continuation fragment of LC
Slot Type : Colour Code 1 CSBK
Connect Plus CSBK : CSBKO=1
Control Channel Neighbour List : 10,0,0,0,0 (0000101000000000000000000000000000000000000000000000000000000111)
4:02:27 PM DMR Data Frame (BS)
CACH : TACT AT=1 Ch 2 Last fragment of LC
Slot Type : Colour Code 1 Idle
4:02:27 PM Short LC : Connect Plus Control Channel SLCO=10 Network: 175 Site: 13
4:02:27 PM DMR Data Frame (BS)
CACH : TACT Ch 1 First fragment of LC
Slot Type : Colour Code 1 CSBK
Connect Plus CSBK : CSBKO=1
Control Channel Neighbour List : 10,0,0,0,0 (0000101000000000000000000000000000000000000000000000000000000111)
 

plutonium233

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I also want to mention that it appears that there are no voice transmissions on this TRS yet. I assume it hasn't been fully commissioned? This is based on CC data, Unitrunker stays parked, and SDR# shows only the control channel in the FFT display (no random transmissions popping up nearby).
 

EricCottrell

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Hello,

The useful information is:
Colour Code 1
Connect Plus
Network 175
Site 13
Site 10 is a neighboring site.

There is a "slow" data stream called Short Link Control (Short LC) that uses the CACH. It takes four frames to send one Short LC. In your example it is indicating the frames have Control Channel Information for a Motorola Connect Plus system.

DMR uses two slots. The first slot on Connect Plus Control Channels carry the control channel frames and the second slot, Idle in your example, can carry voice. You may come across transmissions on other frequencies carrying one or two voice transmissions. If it is part of this site then the Short LC will say it is a Connect Plus Traffic Channel with the same Network and Site Info.

When this site gets busy you will see channel grants on the control channel indicating the Group, Calling Radio Id, Logical Channel Number (LCN) and Slot. You can figure out the LCN to frequency mapping by seeing what frequency becomes active. You can find out the LCN of the control channel when the voice traffic occurs on the second slot on the control channel. The group and other information is also sent before and after a voice transmission on a traffic channel

Some sites are only active if radios are using the site. Business users tend to be daytime (9 to 5), unless it is a 24/7 business like AAA or an ambulance company.

73 Eric
 

plutonium233

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Eric,

Thank you for taking the time to provide this explanation. It helped fill in a few gaps in my understanding of these systems. I'll keep an ear out for any activity on this site so I can start mapping things out.

73's
 

milf

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The DMR conversion/buildout is still a work in progress. It will eventually be an Statewide DMR TRS. I am seeking the SysID (System ID), Site Numbering, CC's in use if any, Color Codes in use, Timing Slots , TG's etc. Once we start to get a real good picture of this, I can flesh it out as I build it in the DB. Most of the Comm South stuff is still LTR, but a large portion of the base for the DMR is active. They are converting both the UHF, and VHF's to become part of the single network. This has been their dream since they first set up the LTR TRS's, as is noted by their letter of intent to the FCC dated several years ago. And since they are the biggest Motorola Dealer/SMR in MS, they logically have the technology, and sites to begin the working for real. So every bit of data for any sites you can receive is awesome. TY very much ...
 
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Gilligan

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Passed through Mississippi along US-20 today. Found sites 6 and 7 for this system. Info as follows:

LCN is unconfirmed for the following sites:
Site 6 (463.3250, DCC 1) - Brandon, MS
Site 7 (461.825, DCC 1) - Forest, MS

I set up a staged Connect-Plus system here: ComSouth DMR Trunking System, Brandon, MS, Mississippi - Scanner Frequencies

I didn't want to set it as displayed yet since none of the LCN info is confirmed yet. Looks like the buildout is coming along...
 

milf

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That adds to at least 2 confirmed sites on coast and I had this staged once but it was just killed. Due to no activity that is the one our Team Leader was getting mad at me about the other day.... Now its back again LOL.... ASAP add the other sites and take it to regular display so he wont get mad again! :)
See also my newer thread on the CommSouth system asking for help!
Sent from my LG-K330 using Tapatalk
 

Gilligan

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The only reason I kept it staged is because there is not any confirmed LCN info for any of the sites. THe announcement was made recently that Connect Plus sites are required to have correct LCN info for each frequency entered. Unfortunately, I was only passing through on my way east and will not have an opportunity to find any LCN info. Hopefully having this post here will spark some interest for listeners in Mississippi who happen to have DSDPlus...
 

milf

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Or an TRX-1/2 or BCD436/536HP..... Anything that can decode DMR... Any help is appreciated.... This system like the Entergy System is one of my lil projects that never completely seems to go the way it should LOL!
 
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