Type II Trunking Question for the experts

[unleashedff248]

Hey guys,

I was posed this question the other day when I was explaining how I didn't want to post my codeplug with my radio ID for everyone to see. I'm nowhere near an expert, but closer than anyone else in my department so I end up answering all the questions.

What would be the implications of two radios having the same radio ID and being used on the system in the case of a Moto Type II Smartnet or Smartzone system? Would it be a 'whoever affiliates first wins' situation?

Also, is the band plan for UHF trunking systems (OBT) transmitted to the radios upon affiliation or is it specified solely in the codeplug?

Thanks a ton!

-Dave

[bernie]

My two bits worth:
My experience with new Motorola trunking systems ended abruptly in '95 when I "retired".
Some one else will have to answer the question regarding "Smart Zone"

Functionally, there is not too much difference between Smart Net, Smart Works, Privacy Plus, Start Site etc. Type 1 or 11.
Duplicate ID.:
The controller has no way to know if you have one unit or dozens with the same ID.
One cannot private call a specific subscriber unit, as all units with the same ID will respond.
The entire Motorola service department in Honolulu at one time used just one ID..mine.

Channel assignment:
Motorola uses "Dynamic Channel Assignment".
The subscriber unit is always on the control channel (OSW) unless on an assigned voice channel.
The code plug in the subscriber unit as well as the Site Controller must have the same "Base Frequency" assignment.
The channel spacing must also be specified.

US 800 band is factory programmed to match the FCC code plan. There is only one "Base Frequency, the Mobile Transmit is always 45Meg below receive, so only one Base frequency is required. The Motorola Channel number is the number of channels above the "Base Frequency" So, channel #356 is 356 X 25 KC above the Base Frequency.

On "Other Band" such as VHF, or UHF requires that the "Base Frequency" of both Transmit as well as receive be specified, allowing any arbitrary TX-RX spacing, such as found in US government 406-420 band. The "Base Frequency" is system wide, must be identical in ALL units, or you will see some very strange problems. Need not be an actual channel assigned to the system.

"Other band" subscriber units have TWO channel numbers sent on the OSW, Receive and Transmit allowing any in band TX-RX pair.
The Control logic is not band dependent. One could have Motorola trunking on Low Band. (Never mind the FCC, as well as practicality.)

[unleashedff248]

Thank you very much, you exactly answered my questions. I'd imagine that there is no difference between smartzone and smartnet, as they are more or less the same system with smartzone having a zone controller with multiple sites. I know this is a HUGE oversimplification, and I may be incorrect here, so feel free to put me in my place.

Thanks again!

[Batwings21]

In smartzone I believe a duplicate id would be a bigger problem, as the radio zone controller could see the same id at multiple sites. I would think the system would then complain about that.

[unleashedff248]

Good point. I'd imagine the most that would happen would be one radio not affiliating, right? Basically, something like this won't cause a system meltdown I'd imagine.

On a side note I found our mobiles have the same ID's as our portables on my county's smartzone system. We only have 2 zones, and since both radios are on the same vehicle, the chances of each being in a different zone are limited.

On another side note I still can't get my XTS3000 to work with the system. All the settings were copied from an XTS2500 from the system. We are not digital, not 9600, and not encrypted. Still, radio will not affiliate. I know we do use the legacy format. Anyone got any guesses to why only Astro25 radios would work here?

Thanks again.

[Victor Xray]

You should ask your system admin for advice and assistance.

[wavetar]

Good point. I'd imagine the most that would happen would be one radio not affiliating, right? Basically, something like this won't cause a system meltdown I'd imagine.

Depending on the situation, it can be a very big problem in a SmartZone system. What happens is radio "A" is affiliated to the system on a specific tower. If radio "B" with the same ID affiliates on a different tower, the system assumes it's the same radio...drops radio "A" off the affiliation list for it's tower, and adds radio "B" to the other. Now radio "A" could potentially receive no radio traffic (if no other radios on it's talkgroup are on that tower). It remains in this 'limbo' state until the user either changes channels, powers on/off, attempts to PTT, etc. Attempting to PTT will result in a 'bonk' tone until the radio can re-affiliate. Once it does affiliate, radio "B" gets booted off, and the cycle continues. When you're dealing with public safety radios and lives potentially on the line, this is not a scenario you want to happen. This is a big reason why it's extremely important to have tight control over the radio programming on a SmartZone system.

On a side note I found our mobiles have the same ID's as our portables on my county's smartzone system. We only have 2 zones, and since both radios are on the same vehicle, the chances of each being in a different zone are limited.

Do you mean there are only two towers? Our provincial system has two "zones", but 68 towers. If the radios affiliate to different towers, you will get the scenario I described above...not related to "zones" at all.

On another side note I still can't get my XTS3000 to work with the system. All the settings were copied from an XTS2500 from the system. We are not digital, not 9600, and not encrypted. Still, radio will not affiliate. I know we do use the legacy format. Anyone got any guesses to why only Astro25 radios would work here?

Has your 3000 worked for you on other systems before? Without seeing your codeplug to verify everything's set correctly, I can only deduce there is a problem with the 3000, possibly low-speed data alignment or similar, to cause this issue. Otherwise, there's no reason it wouldn't work on a 3600bps system, given a legitimate ID is in the radio.

[unleashedff248]

Yeah, we have more than two towers. There are approximately 10 towers per zone, with two zones. I see the problem here...and I can't understand why this was done.

As for my radio, all is legit. The admin won't support the 3000, so I'm left out in the cold. We were instructed to use 2500/5000 models, this way they could just dump the codeplug in and change the ID. But...I figured I could get away with the 3000 I already had without shelling out the extra $1k. The codeplug was looked over mutiple times already by other radio programmers and they can't find an issue. So basically it comes down to my radio, which has never been on a trunking system before. Will a simple alignment procedure fix this issue?

[Ford]

Would you be willing to give us the model number at the least? Or the options installed on the radio? I agree with Wavetar's summation. I'd look into it further, but the following applies.

If the admin isn't willing to let you put it on the network, you shouldn't do it.

[unleashedff248]

It's a H09SDH9PW7BN XTS3000 Model 3. Flashcode is whored out, 591008-4F1E00-9.

It's not that he won't let the radio on the system, it's that he will only offer service to Astro25 radios per our contract. Here's the print summaries in case you don't have the CPS to view the codeplug. Pass is the name of this site. Codeplugs are available.

http://rapidshare.com/files/99102250/XT ... maries.zip


The astro25 codeplug is from my issued radio, and XTS2500. The XTS3000 codeplug is my personal radio.

Everything is legit. I have a legit ID and was issued the system key from the admin himself.

Thanks-

[unleashedff248]

Just a thought: is there a special option for 3600 baud systems? I thought the xts3000 could do those standard with the Smartzone option. We use a legacy control channel format. Does that mean anything special?

Thanks!

[wavetar]

Just a thought: is there a special option for 3600 baud systems? I thought the xts3000 could do those standard with the Smartzone option. We use a legacy control channel format. Does that mean anything special?

Thanks!

The SmartNet / SmartZone option does essentially mean 3600...you need the 9600 option to do 9600 systems. The fact you have a whored out flashcode tells me someone at some point jammed a codeplug into the radio, and it very likely was never tuned afterwards. That is most likely your problem. You need someone with the proper equipment & experience to take a look at the radio to see if they can align it & get it working properly on a trunked system.

Todd

[unleashedff248]

Yeah, I figured as such.
Conventional Rx and Tx work fine though, that's the only thing that throws me. I'll see what I can do about getting it aligned. Thanks for the help.

[wavetar]

Yeah, I figured as such.
Conventional Rx and Tx work fine though, that's the only thing that throws me. I'll see what I can do about getting it aligned. Thanks for the help.

There are several settings, such as high & low-speed data, and compensation balance, which can be out enough to affect trunking operation without impacting conventional rx & tx enough to notice.

[unleashedff248]

oooooo ok. thought about that after I posted. Like I said, I'm new to trunking.

Thanks again for your help and wealth of information.

Anyone wanna tune an XTS3000?

[larrybl]

Thought I would chime in on the dupe ID issue in the orginal post, I did not see any reference to a real issue... but there is, even on a single site system. As a system administrator a duplicate id is a real headace. You have Aliasing issues where mutiple radios show up as the same unit, You can not use Call Alert, Selective Inhibit, or Regroup commands without affecting all the radio with the same ID. If you use the SAC database setting to allow certain features, then this can cause problems.

Bottom line. One ID per radio.

Mt 2 cents
Larry in Waco.