Alternate method of finding DMR LCN?

[Gilligan]

I have a question for the DMR experts. Suppose that my BCD436HP would be programmed with a DMR system with the LCNs programmed out of order. If the frequencies within that system would carry traffic, would the scanner hear anything? Would it even stop for more than a brief moment while the traffic is active on the frequency?

The reason I ask is that I'd like to propose an alternate method of determining DMR LCN, instead of relying on the LCN Finder feature built into the radio. I appreciate the feature, however it seems that there are certain limitations to using it and I've never been able to use it successfully for a system (likely due to having systems in my area that are not very active). If this idea works for Uniden scanners, it will likely work for Whistler radios also.

Suppose you have a DMR system with four frequencies. This method also relies on the idea that the LCN ordering to be discovered would be using LCNs 1, 2, 3 and 4. Could you program sixteen independent DMR TRBO systems into the radio, each with only one frequency, and stepping through the LCN options for each system? For example, you would have four TRBO systems for each frequency, but with LCNs 1, 2, 3 and 4 for those systems. They would be programmed as follows: Freq1-LCN1, Freq1-LCN2, Freq1-LCN3, Freq1-LCN4, Freq2-LCN1, Freq2-LCN2, etc...

By hand, this would take a while. With Sentinel, it would take a few minutes. It seems to me that if the radio only carries traffic on systems with correct LCN ordering, then you would have activity on only four of those sixteen systems. Having the radio record in the background, it seems that you could find LCN ordering pretty quickly if each system was labelled by frequency and LCN programmed. It would just be a matter of replaying audio on the system and seeing which Freq/LCN combinations carried audio.

 

[WX4JCW]

Honestly DSD is the best way

Sent from my SM-N910V using Tapatalk

 

[Gilligan]

Honestly DSD is the best way.

I can't disagree, however having something available in the field, where a computer may not be available, is very useful. Regardless, my goal is to see if this method will work or not.

 

[Gilligan]

I tried out this new method and found positive results. What is slightly confusing is that sometimes the scanner allows audio to pass through (with full TG/RID/CC/Slot info) even when the LCN is not correct, which is what I don't understand. For example, I had one of the frequencies (the most active one) programmed into four separate TRBO systems with LCNs 1, 2, 3 and 4. It was mostly active on one particular LCN, however I still have recordings from the other systems with different LCN ordering for it (just not nearly as many). I am assuming proper LCN order based on the vast difference between how many transmissions I got from each LCN system and testing out this theory by running Trunked Discovery on my results today, although even that will not prove correct LCN order for sure.

 

[kb9hgi]

Honestly DSD is the best way

Sent from my SM-N910V using Tapatalk

what is DSD???

I have a system with 5 freqs and don't know the LCN 2 of the freqs I put the LCN as 1 and 2 and they are working I can hear the system on those 2 don't know if I got lucky or what. I would like to know the LCN for all 5 freqs for sure.

 

[W4UVV]

This may be related to my 536 DMR CP audio interrupt problem

I have a question for the DMR experts. Suppose that my BCD436HP would be programmed with a DMR system with the LCNs programmed out of order. If the frequencies within that system would carry traffic, would the scanner hear anything? Would it even stop for more than a brief moment while the traffic is active on the frequency?

The reason I ask is that I'd like to propose an alternate method of determining DMR LCN, instead of relying on the LCN Finder feature built into the radio. I appreciate the feature, however it seems that there are certain limitations to using it and I've never been able to use it successfully for a system (likely due to having systems in my area that are not very active). If this idea works for Uniden scanners, it will likely work for Whistler radios also.

Suppose you have a DMR system with four frequencies. This method also relies on the idea that the LCN ordering to be discovered would be using LCNs 1, 2, 3 and 4. Could you program sixteen independent DMR TRBO systems into the radio, each with only one frequency, and stepping through the LCN options for each system? For example, you would have four TRBO systems for each frequency, but with LCNs 1, 2, 3 and 4 for those systems. They would be programmed as follows: Freq1-LCN1, Freq1-LCN2, Freq1-LCN3, Freq1-LCN4, Freq2-LCN1, Freq2-LCN2, etc...

By hand, this would take a while. With Sentinel, it would take a few minutes. It seems to me that if the radio only carries traffic on systems with correct LCN ordering, then you would have activity on only four of those sixteen systems. Having the radio record in the background, it seems that you could find LCN ordering pretty quickly if each system was labelled by frequency and LCN programmed. It would just be a matter of replaying audio on the system and seeing which Freq/LCN combinations carried audio.

-----------------

Here is my DMR reception problem:

An established DMR 400 mhz. Capacity Plus multi-site system was reconfigured 2 years ago as a Connect Plus 4 site system. I had my 536 upgraded for DMR and it has been working well except for this CP DMR. I have only one Connect Plus system within my monitoring range. I have a tower mounted pre-amped Scantenna and signal strength is not a problem. All other DMR systems I monitor are fine with no audio interrupt problem.

The 400 mhz. DMR Connect Plus is configured as below:

Richmond = Site One 4 freqs ccs=1,2,3,4 lcns=1,2,3,4
Chesterfield = Site Two 4 freqs ccs=5,6,7,8 lcns=5,6,7,8
Petersburg = Site Three 2 freqs ccs=9,10 lcns=9,10
Tappahannock = Site Four 2 freqs ccs=13,14 lcns=13,14

Yes, I am well aware of the jump in color codes & lcns for Site 3 and don't know why it was done that way. Common sense would have dictated cc11&12 be used but they were not. I have checked the ccs on DSD Plus and they are correct. All CP frequencies are correct. However, I cannot determine the correct lcn sequence so I assigned each lcn the same as the appropriate color code number. I tried different lcns for ccs13,14 but no luck.

The problem I am having is for all CP talkgroup of which there are about 20 users. When a TG individual begins talking continously longer than approximately 3-4 seconds, his/her audio is interrupted with silence lasting for about another 5-6 seconds after which time, if that same person is still talking, what's remains of that particular audio segment continues as if the comm never was interrupted and ends fine. It reminds me of priority or comm port interrupts. It does not happen on any other DMR system I monitor.

I use ARC536PRO software for the 536 and like it. However, I did not install Butel's latest software version because I did not like the add a new FL or overwrite an existing FL file display before saving as new or updating an existing FL. The previous software version works fine.

There are some DMR knowledgeable individuals on the RR forums. Can anyone help me? I have tried everything I can think of. Any help appreciated. I know there is an old EDACS related software for determining lcns which I used years ago. It seemed to be flakey and undependable.
Tnx.


John
W4UVV

 

[kikito]

Suppose you have a DMR system with four frequencies. This method also relies on the idea that the LCN ordering to be discovered would be using LCNs 1, 2, 3 and 4. Could you program sixteen independent DMR TRBO systems into the radio, each with only one frequency, and stepping through the LCN options for each system? For example, you would have four TRBO systems for each frequency, but with LCNs 1, 2, 3 and 4 for those systems. They would be programmed as follows: Freq1-LCN1, Freq1-LCN2, Freq1-LCN3, Freq1-LCN4, Freq2-LCN1, Freq2-LCN2, etc...

Just an idea that could be simpler... What if you program the system only once but put the SAME LCN on all the frequencies. Then on theory, you will only see one frequency be active at any given time. Once you have which one is activating on LCN 1 then repeat by putting LCN 2 on all the frequencies.

Don't know if this will work but might be worth a try. I know the radio won't let you put the same LCN on every frequency but through software I think it lets you.

 

[W4UVV]

It's worth a try

Just an idea that could be simpler... What if you program the system only once but put the SAME LCN on all the frequencies. Then on theory, you will only see one frequency be active at any given time. Once you have which one is activating on LCN 1 then repeat by putting LCN 2 on all the frequencies.

Don't know if this will work but might be worth a try. I know the radio won't let you put the same LCN on every frequency but through software I think it lets you.

--------------
Tnx for the reply....interesting...I had not tried that. I'll give it a try. I'm already well on the path of going nuts dealing with it. What's one more frustration?

Reading more RR DMR related posts today I also learned something new. The new Whistler radios don't have DMR lcns like Uniden does for more accurate lcn/frequency tracking. The Whistler radios search all the target DMR system's frequencies for an open frequency for the talkgroup to use. It's not true lcn/frequency tracking but apparently works ok.

John
W4UVV

 

[jonwienke]

I tried out this new method and found positive results. What is slightly confusing is that sometimes the scanner allows audio to pass through (with full TG/RID/CC/Slot info) even when the LCN is not correct, which is what I don't understand.

It's a bad approach, for the simple reason that to cover all the possibilities, you need to program the factorial of the number of frequencies ( a 6-frequency system would require programming 2 * 3 * 4 * 5 * 6 or 720 different permutations of the same system), and you're going to get a lot of false hits where one frequency has the correct LCN, but others do not. It will take far longer to get a statistically definitive traffic sampling to determine which of the 720 system permutations is getting the most traffic than it would to run LCN Finder. It also assumes that LCNs are consecutive numbers starting with 1, and that is not necessarily the case. On some systems, LCNs may be 5, 11, 17, 23, and 32 instead of 1, 2, 3, 4, 5, and LCN order can be different than frequency order. So it's definitely not a feasible alternative to the LCN Finder.

 

[W4UVV]

Better to know now than later

It's a bad approach, for the simple reason that to cover all the possibilities, you need to program the factorial of the number of frequencies ( a 6-frequency system would require programming 2 * 3 * 4 * 5 * 6 or 720 different permutations of the same system), and you're going to get a lot of false hits where one frequency has the correct LCN, but others do not. It will take far longer to get a statistically definitive traffic sampling to determine which of the 720 system permutations is getting the most traffic than it would to run LCN Finder. It also assumes that LCNs are consecutive numbers starting with 1, and that is not necessarily the case. On some systems, LCNs may be 5, 11, 17, 23, and 32 instead of 1, 2, 3, 4, 5, and LCN order can be different than frequency order. So it's definitely not a feasible alternative to the LCN Finder.

--------------------
Tnx for knowing before I started instead of later. I used it years ago trying to get correct lcns for an EDAC system.

Never mind. I just located the LCN finder after getting some Google help. As I expected most of the Google posts were problems trying to get LCN Finder to work. I was successful in getting a display of all my CP DMR sites. I selected the DMR CP Richmond site 1 and nothing visible dynamic was happening. Am I having visions of having to run my 536 on this one DMR site for 24 or 48 hours to log a matrix and try to figure out what I'm looking at and try to interpret what it means? I haven't checked but from the internet posts, the 436/536 manual on the LCN Finder section was heavy on complaints, leaves a lot to be desired and is not user friendly. I'll try again tomorrow when I have more patience. It reminds me of the EDACS lcn problem I have maybe 10 years ago.

John
W4UVV

 

[W4UVV]

I finally have reception success for this DMR CP!

-----------------

Here is my DMR reception problem:

An established DMR 400 mhz. Capacity Plus multi-site system was reconfigured 2 years ago as a Connect Plus 4 site system. I had my 536 upgraded for DMR and it has been working well except for this CP DMR. I have only one Connect Plus system within my monitoring range. I have a tower mounted pre-amped Scantenna and signal strength is not a problem. All other DMR systems I monitor are fine with no audio interrupt problem.

The 400 mhz. DMR Connect Plus is configured as below:

Richmond = Site One 4 freqs ccs=1,2,3,4 lcns=1,2,3,4
Chesterfield = Site Two 4 freqs ccs=5,6,7,8 lcns=5,6,7,8
Petersburg = Site Three 2 freqs ccs=9,10 lcns=9,10
Tappahannock = Site Four 2 freqs ccs=13,14 lcns=13,14

Yes, I am well aware of the jump in color codes & lcns for Site 3 and don't know why it was done that way. Common sense would have dictated cc11&12 be used but they were not. I have checked the ccs on DSD Plus and they are correct. All CP frequencies are correct. However, I cannot determine the correct lcn sequence so I assigned each lcn the same as the appropriate color code number. I tried different lcns for ccs13,14 but no luck.

The problem I am having is for all CP talkgroup of which there are about 20 users. When a TG individual begins talking continously longer than approximately 3-4 seconds, his/her audio is interrupted with silence lasting for about another 5-6 seconds after which time, if that same person is still talking, what's remains of that particular audio segment continues as if the comm never was interrupted and ends fine. It reminds me of priority or comm port interrupts. It does not happen on any other DMR system I monitor.

I use ARC536PRO software for the 536 and like it. However, I did not install Butel's latest software version because I did not like the add a new FL or overwrite an existing FL file display before saving as new or updating an existing FL. The previous software version works fine.

There are some DMR knowledgeable individuals on the RR forums. Can anyone help me? I have tried everything I can think of. Any help appreciated. I know there is an old EDACS related software for determining lcns which I used years ago. It seemed to be flakey and undependable.
Tnx.


John
W4UVV

------------------------

1. FYI I experimented again yesterday with reassigning logical control numbers (lcns) on the Richmond,VA DMR multi-site CP. All the lcns I previously programed matched their site's frequency's system assigned color codes which were incrementally on three of four sites. Site 4's two frequencys were color coded "13&14" and lcns "13&14". Site 3's two frequency's were color coded "9&10". I changed Site 4's lcns to "11&12" vice "13&14". It made a tremendous difference.

2. My reception still is not a 100% correct on two or three talkgroups monitored. I occasionally can detect maybe a fraction of a second audio interrupt much shorter in time length than a priority channel audio interrupt. I think I'm maybe 99% good which is the difference between day and night when monitoring. Maybe all CP lcns must contain a contiguous number range but can be assigned to each site frequency's non-incrementally.

3. I wish the RR database also would contain a data field for each DMR site's correct lcns for the appropriate site frequencies.

4. Anyway, good for me. Maybe someone reading about my success can benefit from my previously lengthy testing efforts who is having the same problem.

John
W4UVV