Understanding DMR repeater and color codes

[W4UVV]

For the past 2 two years I have been documenting MOTOTRBO users and iding them. I can use DSD 1.4.1 but I now prefer DSDPlus and DMR Decode build 73.. I have opened a MOTOTRBO "can of worms" trying to understand the transmission's data structure and how to relate to other repeater users where applicable using DMR Decode. The first Capacity Plus trs I attempted to analyze is used by a taxi co.and appears possibly active only on 2 of 3 repeater licensed frequencies. But I think that cannot be true. To further complicate matters the license is to the two radio radio installer/maintainer and not the actual user. Two of the three(?) active Capacity Plus system frequencies are from two different previously MOTOTRBO licenses. It gets messy. These two confirmed frequencies are 461.5125 and 463.7875 mhz. and 100% on the comms appear to be on the two out of possibly 3 repeaters. It's like a composite Capacity Plus trs was created by "picking and pulling from two previously modified licenses since modified at that time for MOTOTRBO. None of the frequencies discussed or on a single modified license but two older separate licenses..

Between headaches trying make sense out of DMR Decode data displays below is what I have confirmed so far:

Color code = 1
461.5125 mhz is LCN 1 and LCN 2

461.7875 mhz. is LCN 5 and LCN 6

463.9625 mhz.....sounds like a Capacity Plus control channel and occasionally displays LCN3 and LCN4.
status

I suspect one of the frequencies is is a control channel on 463.9625 mhz. It acts like a control control. I never have heard any voice comms monitoring it. Again this was a frequency previously licensed under one of the previously modified one of two licenses for MOTOTRBO operation.

I use DSD PLus. I can use DSD 1.4.1 but have been using DSD Plus and DMR Decode frequently. Monitoring 463.9625 mhz. I see occasional references to LCN 3 and LCN 4., i.e, "resting on LCN 3" but do not hear any voice transmissions on any MOTOTRBO frequency. I see lots of "LCN 1 and LCN 2 but not LCN 3 and LCN 4. Searching each frequency previously licensed for MOTOTRBO operation, the inference is the 3rd voice repeater frequency is not 463.9625 mhz. If that is true then this Capacity Plus trs actually is a 4 frequency repeater/6 channel trs (1 Control Channel and 6 channel capacity and not a 3 repeater frequencies/4 channel (2 voice repeaters and 1 control channel repeater frequency..

The first of three questions. I have searched the internet and RR forums for 2 weeks+ attempting to locate a color code list of repeater color codes and their cross referenced values to specific frequencies. I don't have to know the frequency cross references but I want to know. I understand the important thing is the color codes are the for the Capacity Plus trs. Can someone please post a color code list or a link to a website where I can download the list or do screen captures?

Please do not post the MOTOTRBO mode technical specs. Please don't post the MOTOTRBO installation systems planning guide. Since I don't understand their heirarcey structured levels or purposes or context I get only headaches trying to follow the various install instructions from these two references.

What I need is a layman's basic tutorial on Capacity Plus systems and a discussion of each unique data element and how to make sense using DMR Decode to relate what data elements display in a Capacity Plus system. I don't like to second guess what is the purpose of a data element and how it relates to the system.

Second question. As mentioned 463.9625 mhz. appears to be a Capacity Plus control channel. Could it also be the missing LCN 3 and LCN 4 numbers which I so far cannot find but is displayed periodically in DMR Decode displays monitoring 463.9625 mhz.? LCN 3 and LCN 4 definitely are being used but running DMR Decode on every MOTOTRBO signal I can receive does not display any LCN 3 or LCN 4.

Third question. If 463.9625 mhz. is a control channel it cannot be a voice repeater. Could it be another frequency on 454-455 mhz. or possibly a 151-156.200 mhz.is part of the trs? No FCC license searches for 454-455 mhz. have been successful for LCN 3 and LCN 4 although I have ided a couple of users by monitoring the voice traffic. All have been LCN 1 and LCN 2 so far. So far I have not heard any MOTOTRBO signals on high vhf and only from 451-455 mhz. and 460-465 mhz. None of them display LCN 3 or LCN 4 using DMR Decode..

I am in a DSD world to myself in central VA. I have to rely on RR forum posts. I don't think I have done anything wrong so far. MOTOTRBO systems are here to stay and increasing in this area and statewide.. My reception range is quite good using my tower mounted pre-amped Scantennas. I would like to better understand the Capacity Plus's data element's purposes (not to the bit level but to the idiot level) signals and trs organization data element structures.

Tnx.

John
W4UVV

 

[Forts]

I think your questions would have been better off in the Motorola forum, or in the 'Understanding Capacity Plus' thread... this really isn't a feature request for DSD+, but let me see what I can do here...

I have searched the internet and RR forums for 2 weeks+ attempting to locate a color code list of repeater color codes and their cross referenced values to specific frequencies. I don't have to know the frequency cross references but I want to know. I understand the important thing is the color codes are the for the Capacity Plus trs. Can someone please post a color code list or a link to a website where I can download the list or do screen captures?

There is no correlation between color code and frequency. The color code is a value from 0 to 15 that is simply assigned by whoever programmed the system, for that particular repeater. If there are multiple repeaters in the system they do NOT need to be the same color code, they can all be different.

As mentioned 463.9625 mhz. appears to be a Capacity Plus control channel. Could it also be the missing LCN 3 and LCN 4 numbers which I so far cannot find but is displayed periodically in DMR Decode displays monitoring 463.9625 mhz.? LCN 3 and LCN 4 definitely are being used but running DMR Decode on every MOTOTRBO signal I can receive does not display any LCN 3 or LCN 4.

If DMRDecode is seeing an LCN 5 and 6, then that means there is a 3 & 4 out there somewhere. When programming the system the LCN's are added in pairs, sequentially. So the first repeater is LCN 1 & 2, 2nd one is 3 & 4 etc etc. So if you are seeing 5 & 6, then 3 & 4 also exists. So it would appear in your case you will have to keep hunting. I find it's easier if you have a 2nd scanner to use. Have the first one running DMRDecode so you can see where the rest channel currently is, and use the 2nd one to search. The rest channel won't have a constant control channel sound on it like P25 or Connect Plus but is usually a 'pulsing' type of signal, just a little blurp every second or so.

If 463.9625 mhz. is a control channel it cannot be a voice repeater.

Sure it can. Remember, two slots per repeater. One can be control and the other voice.

Could it be another frequency on 454-455 mhz. or possibly a 151-156.200 mhz.is part of the trs? No FCC license searches for 454-455 mhz. have been successful for LCN 3 and LCN 4 although I have ided a couple of users by monitoring the voice traffic. All have been LCN 1 and LCN 2 so far. So far I have not heard any MOTOTRBO signals on high vhf and only from 451-455 mhz. and 460-465 mhz. None of them display LCN 3 or LCN 4 using DMR Decode..

It definitely won't be in the VHF range (the radios aren't dual band) so it should *likely* be near the range of the other frequencies, but it doesn't have to be. I have systems near me that have LCN's in the 41x range and in the 46x range.

 

[W4UVV]

Tnx for the info. I have only one DSD configuration. It looks like 463.9625 mhz., which definitely is a control channel is LCN 3 and LCN 4 although I never have heard any audio on this frequency but I have seen LCN 3 and LCN 4 in DMR Decode displays while monitoring 463.5625 mhz. Very confusing.

John

 

[br0adband]

Not meaning to derail the thread but...

- find a frequency with DMR/MOTOTRBO activity (verify the frequency to be as accurate as possible)
- head to the FCC licensing database at this page and choose your state (and area/city if you want but it's not always the same for some systems), punch in the frequency where requested (and use the radio button to select it) - you can also use the RRDB to search in your area and it is sometimes more useful because of the single page layout of info and frequencies
- look at the results of licenses matching that frequency (if you get zero results then you could be off on the frequency - it needs to be exact)
- look at the license to find all the assigned frequencies for the agency or business that owns the license

I've used that method to identify 19 DMR/MOTOTRBO systems here in the Las Vegas area in the past month (by finding just one assigned frequency and then pulling the rest from the license), and without using that method I basically wouldn't have discovered much at all.

Good luck...

We now return you to your regularly scheduled thread, already in progress...

 

[W4UVV]

Please reread my post

Not meaning to derail the thread but...

- find a frequency with DMR/MOTOTRBO activity (verify the frequency to be as accurate as possible)
- head to the FCC licensing database at this page and choose your state (and area/city if you want but it's not always the same for some systems), punch in the frequency where requested (and use the radio button to select it) - you can also use the RRDB to search in your area and it is sometimes more useful because of the single page layout of info and frequencies
- look at the results of licenses matching that frequency (if you get zero results then you could be off on the frequency - it needs to be exact)
- look at the license to find all the assigned frequencies for the agency or business that owns the license

I've used that method to identify 19 DMR/MOTOTRBO systems here in the Las Vegas area in the past month (by finding just one assigned frequency and then pulling the rest from the license), and without using that method I basically wouldn't have discovered much at all.

Good luck...

We now return you to your regularly scheduled thread, already in progress...

First, sorry for posting to the wrong forum. I cannot cross post. Please reread my post. I am very, very familiar with FCC General Menu Searches. Five years ago I and a few area monitors had a similar problem with this two way radio dealer installer/maintainer's licenses vice actual LTR frequencies being used. Some licensed LTR frequencies were "dead". A "composite" LTR operation was created comprised of selected frequencies from three separate LTR licenses, one of them being to the name of the owner, not the company and licensed for operation in a nearby city. The latest modifications only were for MOTOTRBO emission. I have checked and rechecked and monitored every frequency in all three licenses numerous times. I have monitored 25+ other MOTOTRBO transmissions over a 50-75 mile radius and have been successful in iding many of them. None of them are like this situation.

I have been monitoring for the past 55 years. Currently I maintain an 80,000 record user/frequency database for VA which I created in 1985. I do weekly FCC updates for VA. I have 100 ft. tower with mast mounted preamped rotatable preamped Scantennas. I program Uniden and GRE (RS) scanners. Surprisingly, I am the only one I know of in the central VA area with a DSD monitoring configuration. I wish there were more. My other area monitoring friends do not have a DSD configuration.

Again, two licenses are to the 2 way radio installer company and one to the owner and not to the actual frequency(s) users. One "composite" MOTOTRBO operation(Ready Mix) is a standalone using one selected frequency from one of the three licenses. The other "composite" MOTOTRBO Capacity Plus operation (Medical Transport) uses three frequencies two of which are LCN 1, LCN 2, LCN 5 and LCN 6 voice and a third selected frequency which is a control channel. DMR Decode displays occasionally include LCN 3 and LCN 4 confirming they are being used either by the control channel, which I never have heard any voice transmissions on or there is another missing voice repeater frequency for that trs. Remember, some frequencies in the three licenses are not being used..

So, what are you going to do when you monitor every frequency in 3 licenses and hear a "composite" one frequency MOTOTRBO standalone operation and another "composite" Capacity Plus operation on 3 frequencies that best guessing two are confirmed related and another in band MOTOTRBO signal suspected to be a related control channel for the previous two voice repeaters? Unfortunately a FCC General Menu Search is not the solution. It is a beginning only because of the selective picking of frequencies from 3 separate licenses with some frequencies not having any activity and others used in "composite" MOTOTRBO operations. It is not as easy as you suggest. One good thing about MOTOTBRO transmissions, they periodically transmit system status which is 24/7 confirmation that a target frequency is active.

If when the licenses were modified for MOTOTRBO emission the (LTR) frequencies no longer being used were deleted and appropriate frequencies still active reflected as an "Add" onto one of the 3 existing licenses and the other two licenses cancelled, that would have helped tremendously and your suggestion would have been the thing to do BUT that did not happen. An area monitoring friend and I spent two days several years trying analyze, parse and sort license info compared to reality when this mismash was a LTR(s) operation(s). We matched some of the "composite(s)" LTR(s) frequencies but still had some unresolved issues. Same problem now with the only change being MOTOTRBO vice LTR.

If this situation sounds confusing it is. Some things are not as simple as they appear.

John

 

[mtindor]

First, sorry for posting to the wrong forum. I cannot cross post. Please reread my post. I am very, very familiar with FCC General Menu Searches. Five years ago I and a few area monitors had a similar problem with this two way radio dealer installer/maintainer's licenses vice actual LTR frequencies being used. Some licensed LTR frequencies were "dead". A "composite" LTR operation was created comprised of selected frequencies from three separate LTR licenses, one of them being to the name of the owner, not the company and licensed for operation in a nearby city. The latest modifications only were for MOTOTRBO emission. I have checked and rechecked and monitored every frequency in all three licenses numerous times. I have monitored 25+ other MOTOTRBO transmissions over a 50-75 mile radius and have been successful in iding many of them. None of them are like this situation.

I have been monitoring for the past 55 years. Currently I maintain an 80,000 record user/frequency database for VA which I created in 1985. I do weekly FCC updates for VA. I have 100 ft. tower with mast mounted preamped rotatable preamped Scantennas. I program Uniden and GRE (RS) scanners. Surprisingly, I am the only one I know of in the central VA area with a DSD monitoring configuration. I wish there were more. My other area monitoring friends do not have a DSD configuration.

Again, two licenses are to the 2 way radio installer company and one to the owner and not to the actual frequency(s) users. One "composite" MOTOTRBO operation(Ready Mix) is a standalone using one selected frequency from one of the three licenses. The other "composite" MOTOTRBO Capacity Plus operation (Medical Transport) uses three frequencies two of which are LCN 1, LCN 2, LCN 5 and LCN 6 voice and a third selected frequency which is a control channel. DMR Decode displays occasionally include LCN 3 and LCN 4 confirming they are being used either by the control channel, which I never have heard any voice transmissions on or there is another missing voice repeater frequency for that trs. Remember, some frequencies in the three licenses are not being used..

So, what are you going to do when you monitor every frequency in 3 licenses and hear a "composite" one frequency MOTOTRBO standalone operation and another "composite" Capacity Plus operation on 3 frequencies that best guessing two are confirmed related and another in band MOTOTRBO signal suspected to be a related control channel for the previous two voice repeaters? Unfortunately a FCC General Menu Search is not the solution. It is a beginning only because of the selective picking of frequencies from 3 separate licenses with some frequencies not having any activity and others used in "composite" MOTOTRBO operations. It is not as easy as you suggest. One good thing about MOTOTBRO transmissions, they periodically transmit system status which is 24/7 confirmation that a target frequency is active.

If when the licenses were modified for MOTOTRBO emission the (LTR) frequencies no longer being used were deleted and appropriate frequencies still active reflected as an "Add" onto one of the 3 existing licenses and the other two licenses cancelled, that would have helped tremendously and your suggestion would have been the thing to do BUT that did not happen. An area monitoring friend and I spent two days several years trying analyze, parse and sort license info compared to reality when this mismash was a LTR(s) operation(s). We matched some of the "composite(s)" LTR(s) frequencies but still had some unresolved issues. Same problem now with the only change being MOTOTRBO vice LTR.

If this situation sounds confusing it is. Some things are not as simple as they appear.

John

I'm not sure what is unique about this situation. It is not uncommon at all for business trunked LTR/DMR systems to use frequencies from multiple licenses / licenses that don't even belong to them. It's more common than you think. Ohio is full of LTR/DMR systems that use frequencies from multiple active/expired licenses and borrow frequencies from a particular existing license of another agency for which they are serving, etc.

That's half the fun [or not] of figuring out DMR/LTR -- takes a lot of legwork sometimes.

Proof that you can never really go by what the actual license says, and that's why we don't enter data into the RRDB [and haven't for years] purely based upon FCC licenses.

Mike

 

[ASAD]

Is color code equivalent of RAN? What are LCN 1 and LCN 2?
Also, It would be nice to know if DMR is 6.25 kHz equivalent in simplex.

 

[Forts]

Is color code equivalent of RAN?

Basically, yes.

What are LCN 1 and LCN 2?

LCN = Logical Channel Number. It's a method used for the radio to determine which frequency to turn to. Also used in older formats like EDACS and LTR.

Also, It would be nice to know if DMR is 6.25 kHz equivalent in simplex.

Not sure about that one... On 1st gen TRBO radios I don't believe you could operate both timeslots simultaneously in simplex. 2nd gen radios can as one of them gets designated as the master to synchronize timing. So... depending on how you look at it, I'd say technically no for older radios, and a solid maybe for 2nd gen ones. How's that for a committed answer

 

[com501]

DMR is considered equivalent. Since there is no sync in simplex for 1st gen radios, only one timeslot is utilized. As stated, 2nd gen radios can generate sync and use two timeslots. NOT backwards compatible...

 

[ASAD]

As stated, 2nd gen radios can generate sync and use two timeslots. NOT backwards compatible...

So using two timeslots means 12.5. Meaning that DMR can not do 6.25 in simplex? Is that right?

 

[Forts]

Not true 6.25. Basically you'd be using half of the 12.5 allotment

 

[Voyager]

As stated, 2nd gen radios can generate sync and use two timeslots.

This is classic. I recently had a discussion with someone (on this forum I think) who insisted that simplex use of two timeslots is not possible. Maybe it was on a different forum. But, I could not find any docs to support this.

 

[com501]

It is in the MotoTrbo System Planner, it only works for Gen II radios, and one or more have to be masters to generate sync, and they have to be within range of each other.

-And you should never do this on a repeater output, it is NOT compatible with repeater sync, so no one on slot two in the repeater mode will hear you, at all.

 

[Voyager]

Not true 6.25. Basically you'd be using half of the 12.5 allotment

It would be 6.25 equivalent if there are 2 timeslots in 12.5 kHz, but being TDMA it's using the entire bandwidth for both users - divided in time, so it's still 12.5 kHz wide even for just one user based on your specs.

Although DMR is really only 7.6 kHz bandwidth, not 12.5.

 

[Forts]

Which is why I said "Not true 6.25" and "basically". Just making a general point, wasn't looking to quote the tech specs.

 

[Voyager]

Which is why I said "Not true 6.25" and "basically". Just making a general point, wasn't looking to quote the tech specs.

My bad.