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NXDN and DMR on lots of frequencies

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AA6IO

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I was running SDRSharp tonight with DSDPlus and happen to be tuning to a lot of strong signals around 451 and 507 Mhz. There is quite a bit of NXDN and DMR CCs and a lot of voice traffic
For example, on 507.6125, 507.8125, and 508.0125, there is quite a bit of DMR voice These frequencies seem to belong to NEXTEL LTR and are listed as analog in the RRDB. Perhaps a lot of these LTR systems around LA and Orange County are moving to NXDN or DMR instead of analog.
Wonder if anyone else in the area has monitored these with DSDPlus or with a NXDN/DMR capable radio.

Steve AA6IO
 

jazzbassNick

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When the new version of DSDPlus came out, I was "stuck" on this for a bit.
Here's my .frequencies file snippet for the one I fleshed pretty decently.

Code:
; NID: 31 Site 2
NEXEDGE48, 31, 2, 220, 454.122, 0.00, 0
NEXEDGE48, 31, 2, 361, 454.4910, 0.00, 0
NEXEDGE48, 31, 2, 367, 454.4975, 0.00, 0 ;CC
NEXEDGE48, 31, 2, 382, 454.591, 0.00, 0
NEXEDGE48, 31, 2, 795, 470.7, 0.00, 0
NEXEDGE48, 31, 2, 900, 471.3, 0.00, 0
NEXEDGE48, 31, 2, 907, 507.425, 0.00, 0
NEXEDGE48, 31, 2, 911, 507.55, 0.00, 0
NEXEDGE48, 31, 2, 912, 507.65, 0.00, 0
NEXEDGE48, 31, 2, 913, 507.675, 0.00, 0
NEXEDGE48, 31, 2, 942, 507.875, 0.00, 0
NEXEDGE48, 31, 2, 944, 508.5, 0.00, 0
NEXEDGE48, 31, 2, 946, 508.525, 0.00, 0
NEXEDGE48, 31, 2, 948, 508.55, 0.00, 0
NEXEDGE48, 31, 2, 960, 508.725, 0.00, 0
NEXEDGE48, 31, 2, 962, 508.75, 0.00, 0
NEXEDGE48, 31, 2, 1003, 472.931, 0.00, 0
 

AA6IO

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Thanks for feedback Nick. I will do some more investigating in the next few days. I definitely found both NXDN and DMR control channels up in the 507 MHz range, confirmed by Unitrunker with 100% "health."
On one DMR voice channel, they were talking about fixing a 16 Kv transformer, then switched to another voice channel and could not catch it. Does not sound like a typical LTR system.
Anyway, DSD+ working well with my SDRSharp set up and unfiltered audio, with my 996XT and 536HP both with a discriminator tap (yes, I'm probably crazy for tapping the 536HP, but it works well), and with the WS-1080 IF output. Been listening to a lot of NXDN railroad. Not that I care that much about the railroad stations, but nice to hear real NXDN audio.
Going to be spending more time with DSD+ now that I have it set up with a number of different signal inputs. Will start keeping track of some the stuff and post it in the future. Just as I finish this note at about 6:50 AM Sunday morning, there are several DMR voice channels in the 507 Mhz range, likely a DMR trunking system. Maybe two systems. My Unitrunker set-up is showing that some DMR CC is switching between 507.6125 and 508.01250. The 507.6125 is on and off 100% for a few minutes then 0 health. Could be two systems. I am certainly not well versed in DMR. Will have to read up on it.
With this much activity, may think about a DMR radio.
Steve AA6IO
 

Markb

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Hi Nick.

How did you figure out that system? Did you just look for voice activity that matched what the CC was showing? I have one system that I am close on, but there are a few channels that I can't seem to figure out. The FCC licensing doesn't seem to jive, either.
I have been using DSD+ for a while now and like it. I am finding it to be difficult to figure out both Nexedge and DMR systems fully.

Mark
 

jazzbassNick

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Hi Mark,

It took a lot of "intuitive guesswork", I think. The FCC licensing was a little tricky, as the freqs were divided amongst different names. IIRC, I found that using Geosearch and working backwards based on the transmitter location was most reliable. Then whilst monitoring the control channel, I had a second SDR# instance to monitor suspected voice frequencies.

Because I've got multiple sites under the same network ID, if DSDPlus reported the same label but different channel that's when I knew I had a same NID/diff SID.

FWIW, the licenses I happened to find were "broken up" if you will. For example, WQMJ785 and WQLA446 covered the 507 & 508 portions of NID:31 S:2.

Hope that helps ;)
 

bcorbin

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Oh my - just what I need, another distraction 8*)

I did a quick run with an old Pro-2004 and found two systems carrying a lot of traffic up here towards Santa Clarita:

507.9125, 507.925, 507.9625, 508.7375...
...all appear to be part of a DMR/Con+ system. (NID 119, Site 10 DCC 1, NL 8 54 55 56 87)

454.400, 454.625, 471.85, 454.1625...
...all appear to be part of a NexEdge4800 system (NID 31, Site 10, RAN 10, NL 5 11 18)

I'm certain I've missed the 'splinter' frequencies that fall between the old 12.5 kc steps - I may go back and pick those up later on one of my other receivers...

I can't seem to find any documentation on this new (to me) version of DSD+ Can someone translate the NID/RAN/DCC/NL tags? TIA...


(edit) I think I'm getting the hang of this - the following works (so far, more to come) for Site 10:

;NID: 31 Site 10
NEXEDGE48, 31, 10, 331, 454.400, 0.0, 0
NEXEDGE48, 31, 10, 256, 454.625, 0.0, 0
NEXEDGE48, 31, 10, 828, 471.850, 0.0, 0
NEXEDGE48, 31, 10, 888, 472.725, 0.0, 0
NEXEDGE48, 31, 10, 843, 472.225, 0.0, 0
NEXEDGE48, 31, 10, 983, 471.58125, 0.0, 0
NEXEDGE48, 31, 10, 1004, 472.94375, 0.0, 0
 
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Markb

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NID - Network ID
RAN - Repeater Access Number (similar to NAC)
DCC - D? Color Code (also like NAC)
NL - Neighbor List
 

dbord

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I just started learning about NXDM and have a question regarding RAN and NID. Do you have to know the RAN and NID of a system if your just monitoring?

Thanks...
 

bcorbin

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I think I've managed to nail down the Nexedge system I'm hearing:

;NID: 31 Site 10 Ran 10 NL 5 11 18
NEXEDGE48, 31, 10, 256, 454.1625, 0.0, 0
NEXEDGE48, 31, 10, 331, 454.40625, 0.0, 0 ;cc
NEXEDGE48, 31, 10, 415, 454.625, 0.0, 0
NEXEDGE48, 31, 10, 828, 471.850, 0.0, 0
NEXEDGE48, 31, 10, 843, 472.225, 0.0, 0
NEXEDGE48, 31, 10, 888, 472.725, 0.0, 0
NEXEDGE48, 31, 10, 983, 471.58125, 0.0, 0
NEXEDGE48, 31, 10, 1004, 472.94375, 0.0, 0

So - here's how I'm doing it... I've got an old Pro-2004 feeding the CC to DSD while I've got a couple newer radios searching 454 and 471. Whenever I hear Nexedge pop up on a new frequency, I pause the receiver, and watch the Channel Activity window for correlations. I try to update the frequency file frequently - and it looks like, at this point, every new registration is landing on a channel I've identified.

One nice thing about Nexedge... Once I get off the CC and put the radio back in scan mode, I get alphanumeric RID tags with each transmission, so it doesn't take long at all to figure out who is on what TG. There are a LOT of TG's on this system 8*)

There's another Nexedge CC down at 450.150 (NID 105, Site 5, RAN 5, NL 1 2 3 4) - has anyone caught voice traffic on here?

The Con+ system is going to be a bit more complicated because each channel carries two slots (and, in fact, the CC also carries voice). I'll report back on it when I can...


Yeah... this is getting addictive 8*)
 

jazzbassNick

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There's another Nexedge CC down at 450.150 (NID 105, Site 5, RAN 5, NL 1 2 3 4) - has anyone caught voice traffic on here?
Right on - nice diggin'. I found myself using a spreadsheet to keep track what I found, then setup a formula to create the text I needed to add to the frequencies file.

Apparently I had a hit on NID 105 Site 1: CC at 450.31575 (channel 51). The only other hit I have listed in my notes was at 451.894, but I have a note ("Enc?") next to it.

Dang you @bcorbin - I'm gettin' all geeked up on it again ;)
 

Markb

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One nice thing about Nexedge... Once I get off the CC and put the radio back in scan mode, I get alphanumeric RID tags with each transmission, so it doesn't take long at all to figure out who is on what TG. There are a LOT of TG's on this system 8*)
Not sure if you are aware of this, but there is a file in your DSDPlus folder that is called "aliases". It contains all of the RID's (including names of users) and TG's. Just make sure you hit escape when you exit DSDPlus so that newly captured ones are saved to the file.
Here's mine so far:

https://www.dropbox.com/s/40x4x81849f45pd/DSDPlus.aliases?dl=0
 

Markb

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Another thing I am wondering is whether there is a channel plan for this whole thing.
I just made a spreadsheet for all the systems you guys posted, plus mine (PM if you want it) and that appears to possibly be the case.
I am mathematically challenged and can't seem to make the formula work, but do you guys see a correlation here?

http://forums.radioreference.com/2249645-post1.html
 

bcorbin

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Not sure if you are aware of this, but there is a file in your DSDPlus folder that is called "aliases". It contains all of the RID's (including names of users) and TG's. Just make sure you hit escape when you exit DSDPlus so that newly captured ones are saved to the file.
Here's mine so far:

https://www.dropbox.com/s/40x4x81849f45pd/DSDPlus.aliases?dl=0
AH! No, I wasn't. Absent any documentation, that I can find, I've just been winging it.

Thanks for the tip!!
 

bcorbin

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Another thing I am wondering is whether there is a channel plan for this whole thing.
I just made a spreadsheet for all the systems you guys posted, plus mine (PM if you want it) and that appears to possibly be the case.
I am mathematically challenged and can't seem to make the formula work, but do you guys see a correlation here?

http://forums.radioreference.com/2249645-post1.html
I don't think there is, mostly because the channel frequency doesn't vary monotonically with the channel number - on 30/10, ch 983 is on a lower frequency than ch 888.

I kind of suspect this is a little like an EDACS system, where the ops can set up any map they need. That the frequencies mostly rise with channel numbers for the lower channel numbers suggests to me that the ops initially programmed the channel numbers from a sorted list of available frequencies within their licensed set - when new frequencies became available, they tacked them on at the end of the list. I could be wrong, but using a formula where the frequency doesn't increase or decrease consistently with channel number would be a little strange in this application...
 

bcorbin

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It looks like that Con+ system up towards Santa Clarita is described well by:

;NID: 119 Site 10 DCC 1 NL 8 54 55 56 87
Con+, 119, 10, 1, 508.7375, 0.0, 0
Con+, 119, 10, 2, 508.7375, 0.0, 0
Con+, 119, 10, 3, 507.9125, 0.0, 0
Con+, 119, 10, 4, 507.9125, 0.0, 0
Con+, 119, 10, 5, 507.925, 0.0, 0
Con+, 119, 10, 6, 507.925, 0.0, 0
Con+, 119, 10, 7, 507.9625, 0.0, 0
Con+, 119, 10, 8, 507.9625, 0.0, 0

So that just leaves the system on 450.150. I think I can return to my other projects now... 8*P
 

jazzbassNick

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Here's the NID 119 freqs I had in my spreadsheet. I didn't really pursue it much when I was playing with them.
507.6135, 119 ,43
508.00, 119, 8
507.8125, 119, 8
507.788, 119, 9
507.275, 119, 43
 
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