Same Code Plug, Different Behavior on NAS

[BudTurpa]

Issue is that two identical radios seem to not "hear" the same talk groups.

The below an an example of the experience. This all happens in a 15 minute window of time and the radios are placed right next to each other.

Zone 1, Channel 1 = zone channel with a slaved scan list for channels 17, 18, 19 that have the trunked talk groups defined in them.

Talk Group 1 traffic = both radios land and open on the TG
Talk Group 2 traffic = radio 1 lands and opens, radio 2 keeps scanning
Talk Group 2 traffic = radio 1 lands and opens, radio 2 keeps scanning and 10 sec later opens on TG 1 traffic (while radio 1 is still open on TG 2)
Talk Group 2 traffic = both radios land and open on the TG
Talk Group 3 traffic = radio 1 never opens, radio 2 always does

Two APX radios with the exact same code plug. The code plug is designed to scan three Talk Groups off the same site (sub-site), the system is a simulcast.

To troubleshoot I've only configured one control channel, the primary one listed here on RR.

General question, in NAS, if only one control channel is configured and the scan list (via the slaved conventional channel) has only three members in it (Talk Groups all on the same Astro 25 system), how does the radio "monitor" the different talk groups in the list? What would cause the radio to hang up on a talk group and not actually scan all of them (even though it appears to be on the LCD screen)?

Or, are my two radios each listening to different sub-sites (of the simulcast infrastructure) on the same control channel and the sub-sites are simply not broadcasting all three talk groups? But if this, it would challenge my understanding of simulcast systems - where all the sub sites transmit all it's talk groups no matter if no radios are affiliated to a talk group on a specific sub-site.

Any advice or guidance on how to think about this is invited. Thanks!

 

[GTR8000]

All subsites of a simulcast cell transmit the exact same control, voice, and data on an identical set of frequencies.

Is this a multi-site system? By sites I mean either multiple ASR (standalone) and/or multiple simulcast cells; not multiple subsites within a single simulcast cell. Preferred Sites does not work correctly when using NAS, the radio will lock onto the site it believes has the best RSSI. Even if you only program a single control channel, the radio will process any adjacent site messages sent over the control channel, and may switch to another site. This normally only occurs if the trunked system is set to SmartZone or SmartZone OmniLink coverage type. Normally setting that parameter to Disabled and specifying a Site ID will keep the radio locked to one site.

Another factor is the System Search Time parameter in Scan Wide. The default is 2 seconds. That parameter determines how long the scanner dwells on a trunked control channel with a Multi-System Talkgroup or Intelligent Priority scan list. Too low a value and the radio will leave the control channel more frequently to check on the conventional channel, which for NAS is of course of no value. In theory that parameter could be set to 255 seconds, but if the radio is used for "real" and needs to scan a mix of systems, setting it that high has very negative consequences.

 

[BudTurpa]

GTR8000, thanks for the thoughts.

The system I am referring to is large, state-wide. It has multiple stand alone sites and multiple simulcast sites (with multiple sub-sites in each). The three TGs I am scanning in are all part of one of the simulcast sites.

I am not using Preferred Sites, there's no config there.
The System Search Time parameter was (and still is) set to 2 seconds. I get this causes issues when too small or too large, when scanning multiple systems. But, since all three TGs on my scan list are from the same Control Channel I should not have an issue with "2" or "255" - I would expect the same behavior. Am I thinking about that right?

Some steps I took after reading your post:

Removed coverage type from SmartZone/Omni to Disabled and "hard coded" the RFSS and Site. Updated both radios with the new code plug and put them side-by-side on the same three TG scan list. Both radios opened on traffic for TGs 1 and 2 in synch. Only radio 2 opened on TG3 traffic.

Next, I added three additional Zone/Channels with the #1 position still being the original three TG scan list, but also added position #2 and slaved it to a scan list that only has TG1 in it. I did the same for position #3 for TG2 and position #4 for TG3. My plan today is to leave both radios in position #1 (the scan of three TGs list) and when I see only one radio open on TG traffic I will "force" the other silent radio to that TG channel by turning it's knob to the dedicated TG channel position. When the silent radio only has to scan one TG I wonder if it will open up. If it does, that will make me wonder if there is something with scanning NAS and one of the many timers in play.

 

[TomTN]

Two different Motorola radios using the same codeplug but different behavior is an indication that one or both need to be tuned.

 

[com501]

Two different Motorola radios using the same codeplug but different behavior is an indication that one or both need to be tuned.

Exactamundo!! Align both radios. IF you have access to an Aeroflex, use it.

 

[BudTurpa]

No disagreement with misalignment possibly causing my issue, but I think I solved it another way.

I stripped the code plug (being used on both radios) down to a "bare bones" trunking configuration, that meant removing SmartZone/Omni and Trunking Personalities in addition to the one I've been referencing in this thread (that did not have issues). For example, I had a personality defined with different control channels (on the same state-wide system) to monitor other talk groups (not TGs 1-3 as mentioned in this thread).

Once I had only one personalty, one control channel defined, throughout the entire code plug, then both my APX radios NAS TGs 1, 2, and 3 behaved the exact same way. No longer did different TGs open only on one radio, all randomly with no trends.

I read documentation talking about how an APX can "wander off" via spectrum scanning functionality and go land on any control channel defined somewhere else in the code plug (even if the TGs I am scanning in NAS don't live on a full spectrum scan found control channel). I may of read that wrong, or misunderstood it, but I sense my two radios would occasionally land on a control channel not broadcasting a TG I was scanning.

Full Spectrum Scan may not be tied to my issue - but, can anyone give an explanation to how it works in a NAS scenario with multiple trunking personalities and multiple trunking systems defined and/or SmartZone/Omni one or off? Just want to learn more for future programming.

 

[Outerdog]

No affiliate scan is not a complex topic. Once the system details are known, the relevant section in CPS are conventional config/system, trunking config/system, scan lists, and zone channel assignment. And that's pretty much it. Most of those areas are left at their defaults.

With NAS, full spectrum scan should always be turned off. You can read about it in the help file.

What is happening is you have control channels for sites other than the one you wish to monitor programmed. Either get rid of them, or use Preferred Sites -- contrary to popular opinion, Preferred Sites works using NAS.

If you follow this guidance and stop playing with other settings and your radio still does not NAS the system properly, then if you continue to troubleshoot it without getting it aligned, going outside and kicking yourself in the nuts will be more effective. Seriously. I've been down this road with APX and XTS/L. I tweaked and searched and played with every setting. I was stupid. Alignment is the first step.

 

[chrismol1]

GTR8000 already explained this. All my NAS radios are ran on Disabled/Smartnet instead of their actual as a smartzone system each with only the control freqs for the site and talkgroups I want to listen to since not every talkgroup is on all sites. The problem with Smartzone is they are designed to have adjacent sites broadcast in the data stream for seamless switching. A user stays on the same talkgroup as the radio roams between sites and different frequencies and the system controller handles it all the background. This works GREAT for real radios on the system. But you don't always want that adjacent site on a NAS radio. Depending on the design of the system, if the other smartzone sites are NOT simulcasting the talkgroups or have a real radio attached to that site, to the TG you want, and your on the edges of the multiple smartzone sites. It will wander to the BEST signal at that moment, which isn't always the one with the talkgroup you want. You could move the radio feet or a few inches and it could bounce between them on the fringes. A TG will be heard one second and it will be gone the next as it moved to another site. Limitations of NAS must be understood as its built for the radios on the system, not a hobby radio. +1 On alignment, It matters immensely on digital trunked radios