Motorola X2 TDMA

[wpwx694]

before I go out and buy, I just need make sure GRE PSR-800 can monitor Motorola X2 TDMA and p25
thanks

 

[GTR8000]

The PSR-800 can decode Motorola X2-TDMA, but it cannot decode Phase II TDMA.

 

[wpwx694]

will it ever decode Phase II TDMA

 

[GTR8000]

That is unknown. I contacted GRE about that last August, and this was their response:

At this time we don't know if the PSR-800 will be able to decode true P25 Phase II voice or not. We won't really know for certain until a true Phase II system is on the air and we are able to determine exactly what will be needed to decode the signal.

I followed up a few months ago and this was the response:

There has been no change on this front at this point.

Currently the PSR-800 will decode only X2 TDMA. We still do not know if the hardware will be able to handle the Phase II TDMA data at this time.

So basically, if you're looking for a scanner that will monitor Houston's new system, the PSR-800 is the only scanner that will currently decode X2-TDMA. However, that system is slated to go to Phase II TDMA at some point, which means your PSR-800 could wind up being useless if GRE can't get it to decode Phase II TDMA.

It's a crapshoot, really. You can either buy now, listen for as long as you're able to and hope that either the system doesn't switch to Phase II TDMA for a good while...or you can wait until someone comes out with a scanner that decodes Phase II TDMA.

 

[wpwx694]

thanks

 

[GTR8000]

There are quite a few of us in the same boat with this Phase II TDMA. We're building out a large countywide system here in NY that will operate in Phase II TDMA mode from the minute the power is turned on. The fact that there is no scanner out that will decode it, and neither GRE or Uniden have even announced plans for one coming soon, is somewhat troubling.

The funny thing is that the guy who is troubled by it most is the Chief of Communications for the county. He feels it's very important for the public as well as off-duty MOS to be able to easily monitor the system, for transparency and so they know what is going on. Crazy, huh, in this age of encryption and pushing back against live feeds, here's one guy who has the opposite outlook. The county even hosts a few official feeds right out of the 911 Center. Some agencies out there could learn a thing or two from this guy.

 

[SCPD]

Leawood - for your situation in Houston, I'd wait. Hearing the CoH system isn't much incentive. I'd wait for GRE and Uniden to release something that works with TxWARN. As a compromise, if you need some P25 now, buy something used on eBay.

The HoustonScan crowd will be happy to voice their opinions.

 

[KE5TLF]

I followed up a few months ago and this was the response:

There has been no change on this front at this point.

Currently the PSR-800 will decode only X2 TDMA. We still do not know if the hardware will be able to handle the Phase II TDMA data at this time

.

So there are Phase II systems on the air now and have been on the air long enough for them to do some testing. Is it a matter of them now waiting for something to show up on their doorstep, as opposed to proactively visiting these systems, before they'll test this and give us an answer?

 

[GTR8000]

I wish I knew the answer to that. I will say though that the guys at GRE are very responsive and straightforward any time I've dealt with them. To be fair, I'm not quite certain if there are any systems out there that are operating in true Phase II mode yet. The ones listed in the RRDB appear to still be operating in either FDMA or X2-TDMA mode, which plans to eventually go Phase II.

 

[davidzimmerman]

i bough the GRE-800 scanner to monitor the cuyahoga countys new system thats a 700MHZ Motorola system thats a X2 TDMA the scanner was said to be the ONLY one to monitor this type of system. i just got a new BCD396XT last week i did program the 700 X2 TDMA in the bearcat 396XT and it does work maybe a little better than the GRE800 scanner.i got the BCD396XT because the GRE800 eats batteries to fast the 396XT i was able to monitor for 3 days with out the batteries dieing.

 

[GTR8000]

i bough the GRE-800 scanner to monitor the cuyahoga countys new system thats a 700MHZ Motorola system thats a X2 TDMA the scanner was said to be the ONLY one to monitor this type of system. i just got a new BCD396XT last week i did program the 700 X2 TDMA in the bearcat 396XT and it does work maybe a little better than the GRE800 scanner.i got the BCD396XT because the GRE800 eats batteries to fast the 396XT i was able to monitor for 3 days with out the batteries dieing.

No Uniden scanner can decode any form of TDMA, this was confirmed by Uniden's product manager. Chances are that system is still operating in FDMA mode, which is why you are able to monitor it with the 396XT. If it were X2-TDMA or Phase II TDMA, you wouldn't be able to.

 

[KE5TLF]

All systems that are, or eventually will become, Phase II TDMA compliant will always have a FDMA control channel, and will always be CAPABLE of FDMA mode. Some will continue to have radios only capable of FDMA on them for a long time to come too. A decent example of that would be cheap cache radios for handing out during times of "events". So yes you can monitor a system marked TDMA with a FDMA only scanner(your 396XT) to some extent. You just won't be able to copy any talkgroups where ALL the radios are using TDMA. One FDMA radio on a talkgroup makes every radio on that talkgroup work in FDMA mode.

Complete conversion of every radio on a given system to TDMA is still a long way out, but all the really cool agencies will be the first ones to convert most likely, and that is going to start happening sooner rather than later.

 

[SCPD]

My PSR800 does not follow P2 calls.

 

[KE5TLF]

I wish I knew the answer to that. I will say though that the guys at GRE are very responsive and straightforward any time I've dealt with them. To be fair, I'm not quite certain if there are any systems out there that are operating in true Phase II mode yet. The ones listed in the RRDB appear to still be operating in either FDMA or X2-TDMA mode, which plans to eventually go Phase II.

Yeah I know. Just wondering out loud what level of saturation will it take for them to start working on an answer. They are far and few in between, but there would seem to be enough stuff out there now for them to get a decent start on.

 

[ButchGone]

The Tennessee Valley Regional Communication system that's being expanded to a statewide system has also had the ability to to TDMA as well as FDMA.The issue is the radios are crazy expensive, like $6,000 each. Hard to convince local governments that just spent a ridiculous amount of money for radios that cost $4,000 each to turn around and spend millions more for something that basically does the same thing.
BG..

 

[motorola_otaku]

Short answer: The PSR800 will decode X2 TDMA calls on the Public Works 3D8 system, including the new HFD channels. It will not track the Phase II calls on the TxWARN system.

Long answer: The "new city system" is actually two systems: the 800 MHz 3D8 system now in use, and the 700 MHz system which began as an independent system but is now part of TxWARN. TxWARN was already configured for Phase II at the time of the merger so the 700 system began using it from the get-go. The 800 system is still running X2-TDMA since it's independent and will stay that way, but rumor has it that it will be upgraded/migrated to Phase II within the next few months. How that will affect the HFD transition no one (publicly) knows.

I asked a GRE rep at Plano HamCom about future capabilities in the PSR800 and the new 900 mobile, and he didn't seem to understand what I was talking about. The only difference between X2 and Phase II is at the digital layer, so there's no reason I can think of why the physical hardware in the PSR800 couldn't handle Phase II.

 

[GTR8000]

The only difference between X2 and Phase II is at the digital layer, so there's no reason I can think of why the physical hardware in the PSR800 couldn't handle Phase II.

No, that is not correct.

X2-TDMA voice channels use a data rate of 9.6 kbps, while Phase II TDMA voice channels use a data rate of 12 kbps. Given the higher data rate and additional bandwidth required for Phase II TDMA voice channels, there is no guarantee the PSR-800's current physical hardware is up to the task.

 

[KevinC]

Yea!!! Someone got it right!

Sorry, I'm just glad someone else knows the difference.

 

[grem467]

No, that is not correct.

X2-TDMA voice channels use a data rate of 9.6 kbps, while Phase II TDMA voice channels use a data rate of 12 kbps. Given the higher data rate and additional bandwidth required for Phase II TDMA voice channels, there is no guarantee the PSR-800's current physical hardware is up to the task.

Its also a completely different modulation scheme as well, but your point is still valid.

X2 TDMA on 3D8 is VERY temporary. Once it is migrated to 1A7, it will be uplifted to phase II as well.

 

[Ensnared]

GRE Awareness of Type II

That is unknown. I contacted GRE about that last August, and this was their response:



I followed up a few months ago and this was the response:



So basically, if you're looking for a scanner that will monitor Houston's new system, the PSR-800 is the only scanner that will currently decode X2-TDMA. However, that system is slated to go to Phase II TDMA at some point, which means your PSR-800 could wind up being useless if GRE can't get it to decode Phase II TDMA.

It's a crapshoot, really. You can either buy now, listen for as long as you're able to and hope that either the system doesn't switch to Phase II TDMA for a good while...or you can wait until someone comes out with a scanner that decodes Phase II TDMA.

I contacted GRE as well. In fact, I sent them a hyperlink for the new 700 system in Houston. Previously, they stated that they were unaware of any such systems in operation. So, I tipped them off to what might be happening in Harris county.