DSDPlus DSD+ decoding wrong site number on DMR?

[AM909]

I've got a DMR TIII site in my list that I've heard previously, decoded as site "L1-1" by DSD+ (unknown which DSD+ FL version, but no more than ~15 months old).

Yesterday, decoding with DSD+ FL 2.368 via VBCable from SDR# playing a recent capture from that same channel (935.5125 in SoCal), I got site "L2-1.2" instead. Because it seemed to be the same site, I did some combination of restarting, keyed "D" (to discard current system info), and "N" to reset the neighbor list and decoded it again at least once, seeing L2-1.2 each time.

Today, decoding a different capture of the same freq, I got "L1-1". I went back to the same file I decoded yesterday, and it now decodes as "L1-1" also.

Both yesterday and today, I noted in the console log "SYS_Parms: SysCode=10.0001.00000001". Is this related, and what do the components mean? That is the only unique set of values shown for the SysCode in all the SYS_Parms messages in the log.

I've linked raw recordings from DSDPlus above. Unfortunately, I don't have a recording from yesterday, but I've provided today's recording of decoding the same file that was being decoded yesterday.

[time passes ...]

Playing with decoding the earlier file, I've now got a DSD+ raw recoding and an SDR# raw recording (96MB of 2.4 MSPS IQ) of it first decoding L1-1 at the 4s mark, then decoding L2-1.2 at the 20s mark. There's also the console log and event log.

[add:] FWIW, the same thing happens on 935.5250.

Any ideas?

 

[dlwtrunked]

In the DC area, there is a 400 MHz DMR trunk multi-site system where two of the three locations use the same frequencies. Depending where you are, you decode a different site of it. You could have a similar system there where the site you are receiving is changing on the frequency.

 

[slicerwizard]

For SysCode 10.0001.00000001, I would expect to see L1-1 for a Motorola Capacity Max system and L2-1.2 for a true Tier III system.

 

[thewraith2008]

This is an old problem with DSD+ and DMR CAP MAX.
It will see it as L1-1 onetime then next time you tune to it, it will see it as L2-1.2.

Until they (DSDPlus) fix it and decide which way they want to decode it, you will need to define all the network/site/frequency files for both L1-1 and L2-1.2.

I believe the L2-1.2 is the correct one as it follows the other TIII site code decoding conventions that DSD+ uses.

 

[AM909]

I guess, if nothing else, the console log should show something like "SysCode=10.0001.00000001 (Cap+ L1-1)" or "SysCode=10.0001.00000001 (TIII L2-1.2)" in addition to dumping the message(s) it uses to decide the flavor, which would have immediately pointed to the cause in my case. Maybe add a debugging level 5 with more of this type of stuff in case people don't want to see it at level 4.

 

[slicerwizard]

I've now got a DSD+ raw recoding and an SDR# raw recording (96MB of 2.4 MSPS IQ) of it first decoding L1-1 at the 4s mark, then decoding L2-1.2 at the 20s mark.

[add:] FWIW, the same thing happens on 935.5250.

Any ideas?

You're not monitoring a trunking system. You're monitoring a single traffic channel on a Capacity Max system. DSD+ isn't displaying the (MOT) tag that one sees when on a CapMax control channel. I would hazard a guess that the traffic channels don't carry enough information to reliably determine if the channel is part of a Capacity Max system or a true Tier III system, or perhaps they don't carry the specific information that DSD+ uses to make the distinction. (As an aside, to me, this has the familiar stench of Motorola and their "fsck standards" attitude...)

Try monitoring 938.425 (the control channel); I don't see any network ID / site ID weirdness/variability when monitoring Tier III or CapMax control channels.

I believe the L2-1.2 is the correct one as it follows the other TIII site code decoding conventions that DSD+ uses.

No, L1-1 would be the correct numbering since it's a Capacity Max system. Those are the network ID and site values that the system administrator / techs entered when setting up the system.

 

[thewraith2008]

No, L1-1 would be the correct numbering since it's a Capacity Max system. Those are the network ID and site values that the system administrator / techs entered when setting up the system.

OK that's good to know.
I'm sure I asked about which was right one once before and if someone in the know knew.

... I don't see any network ID / site ID weirdness/variability when monitoring Tier III or CapMax control channels.

I see a few CapMax systems now that have replaced CON+ or other older systems and the miss detection of the SysCode happens enough to be annoying and it's why I don't use DSD+ for CapMax now.

 

[thewraith2008]

No, L1-1 would be the correct numbering since it's a Capacity Max system. Those are the network ID and site values that the system administrator / techs entered when setting up the system.

OK, I found some official Motorola documentation to backup what slicerwizard has stated about the correct SysCode.
I just wanted to find another source to verify this.

From: MOTOTRBO Radio Management 2.0 User Guide

 

[AM909]

Wayne Holmes talks about this offset issue here, too. Reading more from the Motorola doc mentioned above, I wonder if there is a typo in Table 152 at 3.50.6.1.1 Site ID. Based on that blog post, the Network and Site fields comprise 12 bits of the 16-bit SIC, with the number of bits for each depending on the System Type. The table at 3.50.1.5 (in the image above) confirms that the Network portion of the 12 bits has a length of 9, 7, 4, or 2 bits for Tiny, Small, Large, and Huge models, respectively. This leaves 3, 5, 8, and 10 bits for the Site ID field. That means the maximum value of the Site ID can be 7, 31, 255, and 1023. The first two (Tiny 7 and Small 31) agree with the table at 3.50.6.1.1, but the Large 1023 in the table does not agree, and there is no Huge model in the table at all. Is this an error in the doc or is there some other explanation?

 

[thewraith2008]

Yes Huge does seem to missing from the Site ID table (3.50.6.1.1 - Table 152).
You would expect it to be:

• Tiny 0-7
• Small 0-31
• Large 0-255 *
• Huge 0-1023 *

* White paper for Capacity Max say it only supports up to 250 sites.

The way I read it is a Network ID can be any number between 0-511 depending on model (T,S,L,H) chosen.
For Site ID, it can be any number between: 0-1023 depending on model (T,S,L,H) chosen and cannot be more than 250 numbers (sites) used.


Skimming though the document shows why area part of the SysCode is not used. (see 3.50.1.8)

Location Area Length (bits)
This field allows you to set the Capacity Max Location Area.

A location area is a group of sites where the radio is not required to register explicitly while roaming among the sites in the group. In Capacity Max, a location area only contains one site, and therefore is not configurable if the System Type is Capacity Max Open System, or Capacity Max Advantage.
If a radio is configured with a System Type of Capacity Max Open Radio and therefore operating on
another manufacturer system, then a location area mask length can be configured. The value of the
location area mask length is limited by the configured Network Model.

NOTE: Any references to MOTOTRBO Radio Management 2.0 User Guide is from DECEMBER 2021 MN003734A01-AK version