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Over My Head: DMR

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Ensnared

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#1
I have a 436HP. I am attempting to analyze a DMR system in Waco, Texas. My only experience with voice/control decoding software involved Pro96.com and my GRE PSR 500. I was able to effectively analyze and submit information for the VHF trunking system in Woodway, Texas.

Now, I attempting to analyze, program, and possibly submit radio information for the DMR system used by Baylor University PD. I found the call sign, WQMM459 -. I determined what type of DMR is being used, 2-slot DMR (Motorola MOTOTRBO) TDMA voice.

I have used the DMR search too for my county; however, these are not listed by call sign. Baylor University has several DMR systems, not the one I am attempting to analyze.

Is there any voice/control channel decoding software I can use with my 436HP?
 

Markb

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#2
I don't think there is a DMR analyzer/decoder that will work without adding a descriminator tap to your scanner. Also, you would still need to find the correct system frequencies, assuming it's trunked.

My recommendation is to enter all frequencies in the licence that are station class "FB2"
and scan them conventionally. You should be able to hear traffic, determine the color codes and whether the system is conventional or trunked (Connect Plus, Capacity Plus, etc...).
Once you find the frequencies that you believe are in the same system (may have same color code or same type of traffic at least), create a MotoTRBO sytem in your scanner with the LCN for each frequency set to zero.
Once you have determined the system type, color code(s) and likely frequencies, use the analyze feature to determine channel order. The analyze feature will only work when the system is busy.
Once you have the LCN figured out along with the previously mentioned data points, you can use the discovery tool to figure out the talkgroups.



Sent from my SM-N930V using Tapatalk
 
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#3
Trying to figure out a DMR trunking system basically sucks. You have to manually search with a scanner, log your results, use DSD+ fa$tlane to see the LCNs, and try to piece it all together. I created an Excel spreadsheet for my local area and made SOME progress, but it's hard. The colors are frequencies from the same system.

Zippyshare.com - DMR Trunked Systems.xlsx
 

Markb

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#4
The Color Code doesn't have to be the same for a whole system. It *could* vary.
Also, I don't think you need DSD+ to get LCN info. I have had pretty good success with the analyze feature.
Figuring out DMR just takes patience and a little bit of detective work.

Sent from my SM-N930V using Tapatalk
 

Ensnared

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#5
Foggy

Trying to figure out a DMR trunking system basically sucks. You have to manually search with a scanner, log your results, use DSD+ fa$tlane to see the LCNs, and try to piece it all together. I created an Excel spreadsheet for my local area and made SOME progress, but it's hard. The colors are frequencies from the same system.

Zippyshare.com - DMR Trunked Systems.xlsx
Yes, I am starting to see this is a going to be a daunting task. The problem that exists for me is when I used the DMR tool specific to the county, it shot out color-coded conventional frequencies. I followed the instructions and imported these into Sentinel.

I previously eliminated the DMR frequencies I was not interested in analyzing. However, Baylor University has several DMR systems listed. Hence, there is a long list of frequencies. How does one differentiate between the frequencies and the associated DMR system? Texas Scanner Frequencies and Radio Frequency Reference

I thought the DSD would show the frequencies specific to the call sign and/or DMR system. If I knew which frequencies to load, I could find a similar system and insert the frequencies into the various sites.

For the purpose of comparison, I looked at another DMR system in Dallas, Texas. It was called DFW Communications. None of the system frequencies listed in the RR DB showed up on the FCC call sign frequencies. So, yes, this is a steep learning curve.

Here is the system I used for comparison, trial and error. DFW Communications DMR Trunking System, Dallas, Texas - Scanner Frequencies

Not all of the system frequencies are showing up in the frequencies listed for this call sign. I do see 463.40, not all of the others. I looked for the frequencies associated with FB, but it showed FB6. So, in essence, the only frequency listed among the frequencies associated with this call sign is 463.40. Now, I am really getting confused.
 
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UPMan

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#6
As mentioned above, you only need to look at frequencies with either an FB or FB2 station class. Also, you only need to look at frequencies with an emission designator of 7K60FXE. (To see the above, you need to click on the license link to get to a page that looks like WPVM514 (BAYLOR UNIVERSITY) FCC Callsign Details).

You then have to pretty much brute force monitor the individual frequencies to determine whether they are DMR Conventional, DMR Tier 3, MotoTRBO Connect Plus, or MotoTRBO Capacity Plus, etc. All the frequencies for an entity are typically (but not necessarily) all on one license.

Connect Plus systems are easiest to identify channels on, as they transmit a System and Site ID on each channel (when they are active). Capacity Plus is much more difficult to determine all the associated frequencies, as there are no similar identifying data transmitted by channels on these systems.
 

Ensnared

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#7
Roger

I don't think there is a DMR analyzer/decoder that will work without adding a descriminator tap to your scanner. Also, you would still need to find the correct system frequencies, assuming it's trunked.

My recommendation is to enter all frequencies in the licence that are station class "FB2"
and scan them conventionally. You should be able to hear traffic, determine the color codes and whether the system is conventional or trunked (Connect Plus, Capacity Plus, etc...).
Once you find the frequencies that you believe are in the same system (may have same color code or same type of traffic at least), create a MotoTRBO sytem in your scanner with the LCN for each frequency set to zero.
Once you have determined the system type, color code(s) and likely frequencies, use the analyze feature to determine channel order. The analyze feature will only work when the system is busy.
Once you have the LCN figured out along with the previously mentioned data points, you can use the discovery tool to figure out the talkgroups.



Sent from my SM-N930V using Tapatalk
As perplexing as this task has become, I am going to experiment with the system in question by entering them as FB frequencies, conventional first. I am assuming you are talking about the analyze system on my 436HP, right?
 

UPMan

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#10
Look at location, too. More than likely, all the system's channels will be tied to the same physical site (again, not exclusively, but typically).
 

Ensnared

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#12
Thanks

I did a quick sort/delete in Excel and made the following lists:

Loc # Frequency
9 460.9
9 452.3625
9 453.0125
9 461.7
9 452.4375
9 452.2375
9 461.1

Loc # Frequency
1 461.15
1 452.3625
Before I read you response, I followed the DMR import tool to the letter. I loaded all of the DMR frequencies for Baylor as conventional. I thought I would have heard something. Perhaps, I did not load the DMR upgrade right. I will double check to see if this has been loaded right.

As suggested by a previous post, I also came up with the exact same list of FB2 frequencies you listed, but I haven't listed them alone yet. Some have said that the FCC license can say conventional and still be trunked.

From what I'm understanding, the DMR ordeal can be a daunting task, even for experienced listeners.

I have been told there is something called a "rest" channel. Does the RRDB have any plans to come up with a DMR-specific template for DMR downloads?. Some, have said a DMR systems does not use a "control channel", but I believe I've seen some listed as blue or red.

Here is an example: DFW Communications DMR Trunking System, Dallas, Texas - Scanner Frequencies

Onward Through The Fog: "Oat WIllie's"
 

Ensnared

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#13
Bingo: Short Voice Bursts

Today, I heard activity on the Baylor DMR. I heard very short sections of conversations. It was in the clear, but there was another transmission that carried no voice. I set these up to have the tone 7, the most annoying Uniden tone I could find. This triggered me to view the radio results. I am thinking this is a trunked system and that silent channel was something to do with it.
 

Ensnared

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#14
Cut and Paste

I did a quick sort/delete in Excel and made the following lists:

Loc # Frequency
9 460.9
9 452.3625
9 453.0125
9 461.7
9 452.4375
9 452.2375
9 461.1

Loc # Frequency
1 461.15
1 452.3625
I am assuming there are two sites and/or locations. I am likely dealing with a trunking system. I heard short voice bursts and one silent channel on the Baylor DMR conventional frequency load.

Do you think I could take a radio system and use the structure, change the guts as in operating frequencies. I don't know whether to call the mode column "T" or not, but I might load this as a trunking system and see what happens. I just need to know if these two sites and associated frequencies are to be loaded in two sets of system frequencies encompassing all of the frequencies you listed.
 

Ensnared

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#15
Cut and Paste

I did a quick sort/delete in Excel and made the following lists:

Loc # Frequency
9 460.9
9 452.3625
9 453.0125
9 461.7
9 452.4375
9 452.2375
9 461.1

Loc # Frequency
1 461.15
1 452.3625
I am assuming there are two sites and/or locations. I am likely dealing with a trunking system. I heard short voice bursts and one silent channel on the Baylor DMR conventional frequency load.

Do you think I could take a radio system and use the structure, change the guts as in operating frequencies. I don't know whether to call the mode column "T" or not, but I might load this as a trunking system and see what happens. I just need to know if these two sites and associated frequencies are to be loaded in two sets of system frequencies encompassing all of the frequencies you listed.

The silent channel has been consistent, "45MO5G" on 461.70 mhz.

Well, that didn't work very well. I need to learn how to create a trunking DMR, built from scratch. I tried to change the lat/long but I did not know what to put for the department. It showed a location that I could not remove. Back to the drawing board.
 
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Ensnared

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#16
Blank Round

Well, I experimented a bit. What is going to happen? I mean it is not like my radio is going to do a Galaxy S7 or something. So, I went into ARC 536 Pro and created a DMR trunking. I could not figure out how to do the same in Sentinel. So, I shot it to the radio. Then, I shot the radio contents into Sentinel and moved the favorite, Baylor DMR into my favorites list. I am waiting. I doubt I will hear much traffic tonight knowing that all Baylor Students are sound asleep. Tomorrow, I will see if my bait works and I can catch some DMR fish. I have ID search activated. I created two sites, as UpMan listed. I put in the location for each site and labeled them with a 20 miles range. Let's see what happens. I read that listing the FCC frequency ID number was a good place to start for determining LCN. I tried running analyze, but I guess they would have to be talking in order to do this function.
 

natedawg1604

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#17
.... I read that listing the FCC frequency ID number was a good place to start for determining LCN. I tried running analyze, but I guess they would have to be talking in order to do this function.
It sounds like you're relying too much on ULS. FCC data has very limited utility, especially for private LMR systems. And no, the ULS frequency ID number tells you nothing, there is no data field in ULS which would provide LCN order.

To find comprehensive data on local DMR systems, you must "manually" search the entire UHF business band by (for example) running an analog band search in NFM mode and documenting frequencies with a loud annoying motorboat sound - they are VERY hard to miss if the DMR signal is somewhat strong. It's actually pretty simple once you get familiar with the process. Many also find it helpful to get a few $20 RTL dongles, because you can use DSD+ to automatically determine the LCN pair of a DMR frequency, along with system type, System ID etc. If a particular DMR frequency is active (or at least broadcasts regular idle messages), DSD+ will quickly spit out all relevant system parameters in very short order. Moreover, DSD+ will tell you IF the frequency is DMR, and if so, whether it's Conventional DMR, Capacity Plus or Connect Plus. Also, it detects & decodes Nexedge, IDAS, D-Star, ProVoice and of course P-25.

Also, RTL dongles allow you to use SDR#, which providers a great spectrum analyzer view over 2.4 MHz of spectrum, which can also assist with identifying DMR freqs.
 
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Ensnared

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#18
Thank You

It sounds like you're relying too much on ULS. FCC data has very limited utility, especially for private LMR systems. And no, the ULS frequency ID number tells you nothing, there is no data field in ULS which would provide LCN order.

To find comprehensive data on local DMR systems, you must "manually" search the entire UHF business band by (for example) running an analog band search in NFM mode and documenting frequencies with a loud annoying motorboat sound - they are VERY hard to miss if the DMR signal is somewhat strong. It's actually pretty simple once you get familiar with the process. Many also find it helpful to get a few $20 RTL dongles, because you can use DSD+ to automatically determine the LCN pair of a DMR frequency, along with system type, System ID etc. If a particular DMR frequency is active (or at least broadcasts regular idle messages), DSD+ will quickly spit out all relevant system parameters in very short order. Moreover, DSD+ will tell you IF the frequency is DMR, and if so, whether it's Conventional DMR, Capacity Plus or Connect Plus. Also, it detects & decodes Nexedge, IDAS, D-Star, ProVoice and of course P-25.

Also, RTL dongles allow you to use SDR#, which providers a great spectrum analyzer view over 2.4 MHz of spectrum, which can also assist with identifying DMR freqs.
This sounds like I could do this with my Pro 2042, hearing annoying sounds and such. The search function on this radio is so much easier to work. I have been reading about those who analyze the system using RTL dongles and such. I have looked and found one with an antenna. I don't know if these are necessary, but I suppose it cannot hurt. There are many brands. Do you have any recommendations for a brand? Before you mentioned it, I was searching and found the DSD+ software.

I once used my 2042 to discover various trunking systems in the VHF range, which later changed to marine bands. Woodway, Texas went to an auction in Galveston to buy marine band pairs to use in their VHF trunking system. I kept up with the changes by using Pro96Com.

Yes, I've heard the sound you mentioned and it is quite annoying.

Again, thanks.
 
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ka3jjz

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#19
Yes, a modified 2042 would work just fine for apps such as DSD+. I believe you would need a second receiver (a RTL-SDR would do, I think) if you were actually going to follow the trunking.

You can look up on the net to find out how to put a discriminator tap on a 2042, or you could have someone like G&G do it for you.

Mike
 
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