VIC MMR tracking with DTS96/PRO96

Mike Alpha
Posts: 672
Joined: Thu Aug 14, 2008 8:22 pm

VIC MMR tracking with DTS96/PRO96

Post by Mike Alpha » Wed Dec 07, 2011 10:59 pm

I was in Melbourne last week and had a DTS96 with me. With the NSW P25 system settings in the scanner I found could not track the Vic MMR. Here I was thinking that the P25 systems in Australia would all use the same trunk settings, ie, base/offsets etc, but that's not the case.

The NSW P25 settings are:
# Ch LO Ch HI Base Freq Offset Step
00 16384 20479 16384 412.4750 06.25

and I found out to track all the Vic MMR sites you need the following table set up.
# Ch LO Ch HI Base Freq Offset Step
00 8192 12287 418.1000 8192 6.250
01 12288 16383 420.0125 12288 6.250
02 16384 20479 421.2625 16384 6.250
03 20480 24575 422.2625 20480 6.250
04 24576 28671 425.2625 24576 6.250
05 28672 32677 465.0750 28672 6.250

Without a computer and software I wasn't able to input the above table into the scanner (much to my wife's delight) so I had to go without.

So how does this affect interoperability between Vic MMR and NSW GRN radios??

Mike

User avatar
Bigfella237
Posts: 1895
Joined: Fri Feb 26, 2010 3:11 pm
Location: In geosynchronous orbit above the Far South Coast of NSW, Australia

Re: VIC MMR tracking with DTS96/PRO96

Post by Bigfella237 » Thu Dec 08, 2011 12:49 am

G'day Mike,

The only thing really required for interoperability is if both systems can be programmed into the same radio!

True interoperability requires each user radio to have "Intra-WACN Roaming" enabled so a radio with only one system programmed can roam onto another system within the same WACN but that requires an AWK (Advanced WACN Key) and I doubt anyone outside of Motorola has one?

It also requires that all systems subscribe to a common RID plan (so there are no conflicts) and the same talkgroups would also have to be duplicated across all systems (pointless having a fire radio roam to another system only to find that their talkgroups there are used by the ambulance service for example)?

I don't believe that a common bandplan would be necessary (although it would probably save some time) as the radio will do a full spectrum scan anyway if it can't find a valid control channel on the OBT Control Channel list from the existing system?

The MMR has all those bandplans because they had to incorporate several different PMR networks and their hardware, also certain frequencies on that system are reserved (for example, only VicPol radios can use the 465MHz + bandplan) so as to guarantee availability, I suspect something simular will happen with our GRN before the NSWPF migrates?

At the moment, any radios that need to roam to another system (such as the VICMMR) simply have both systems programmed with separate RID/Talkgroups for each. There are also certain common talkgroups linked via RoIP between the systems to allow calls to be passed interstate.

Apart from all that, I'm not familiar with the DTS96 or PRO96 but with Uniden scanners you don't need to enter a bandplan on explicit P25 systems, just enter the control channel frequency and the scanner gets the bandplan off the data stream, they've had this ability since at least the old BC796D?

Andrew

citabria
Site Admin
Posts: 1064
Joined: Thu Aug 14, 2008 8:22 pm

Re: VIC MMR tracking with DTS96/PRO96

Post by citabria » Thu Dec 08, 2011 2:19 pm

Mike Alpha wrote: So how does this affect interoperability between Vic MMR and NSW GRN radios??
Mike, the P25 control channel actually broadcasts this information across to all subscriber radios so it doesn't even need to be programmed in. Real P25 radios all use this "Implicit trunking" mode to get the band plans from the infrastructure itself.

This is how the 996 works in P25 CC only mode.

The DTS96 is the exception to the rule, for some reason they didn't think to put support in for this P25 feature.

If you run PRO96COM software, it will show you the bandplan being transmitted over the control channel.

Cheers,
Matt

Mike Alpha
Posts: 672
Joined: Thu Aug 14, 2008 8:22 pm

Re: VIC MMR tracking with DTS96/PRO96

Post by Mike Alpha » Thu Dec 08, 2011 3:49 pm

Thanks Andrew and Matt. I was aware of the band plan being broadcast in the CC data but my confusion was with what actual information has to be programmed into each radio not transmitted over the CC data? With the Vic MMR seemingly a lot more complicated having different sites running on different band plans, would a NSW P25 radio be able to do a seemless transition into the Vic MMR, or would the Vic MMR system have to be programmed into a separate zone?

Mike

ivahri
Posts: 843
Joined: Sun May 31, 2009 8:24 pm

Re: VIC MMR tracking with DTS96/PRO96

Post by ivahri » Thu Dec 08, 2011 7:09 pm

Mike,

It couldn't be "seamless" as it is a separate network, but it could be programmed into a radio as an additional trunking system. The XTL5k/XTS5K have a capacity of 20 trunking systems so that wouldn't be a problem for any NSW radio. However it would have to have a Victorian radio ID & Victorian talkgroups (they could be made to look the same to the user & be linked back to NSW) assigned.

Please note that NSW FRNSW radios operate on the SAGRN (in P25)... but using SA radio IDs & talkgroup. The same radios are capable of operating on the NSW GRN (though not from their normal QTH of Broken Hill...).

Cheers,

Richard

SKEYGEN
Posts: 90
Joined: Sun Oct 02, 2011 2:22 pm

Re: VIC MMR tracking with DTS96/PRO96

Post by SKEYGEN » Thu Dec 08, 2011 7:25 pm

Seamless roaming is possible between P25 systems, but whether Motorola's current infrastructure can support it is another matter, and to my knowledge it's not implemented on any systems in Australia yet. Not doable for SA at this stage of course, their system is still Type II.

The P25 ISSI specifications provide the ability for systems to be interconnected to allow roaming radios to be properly authenticated against their home system, and to be able to send and receive packet data and voice traffic to subscribers on their home system. The documentation I've seen so far suggests they've borrowed a hell of lot from GSM in how this works conceptually, particularly where unit registration and packet data is concerned.

I'm guessing this is the eventual grand plan for Australian GRN systems, based on the unit numbering schemes we see that are clearly designed to not overlap from state to state.

ivahri
Posts: 843
Joined: Sun May 31, 2009 8:24 pm

Re: VIC MMR tracking with DTS96/PRO96

Post by ivahri » Thu Dec 08, 2011 8:09 pm

I don't believe there is any intention to implement seamless roaming. Why? How many network users cross state boundaries? Very very few. All that would do is introduce a whole lot of new management challenges for network managers for a feature used very rarely. For those who do cross state boundaries there are ways- I know because I did it. I'm speaking from experience when I note how tough it was, technically very simple but administratively very challenging even with the support of 2 state governments.

Richard

Mike Alpha
Posts: 672
Joined: Thu Aug 14, 2008 8:22 pm

Re: VIC MMR tracking with DTS96/PRO96

Post by Mike Alpha » Fri Dec 09, 2011 11:30 am

So where are we at with interoperability between NSW GRN and Vic MMR? Or is it still a bit too soon? If we had a - dare I mention it - Cyclone Tracey scenario now, are there common liason TGs accessible to both systems or will there be a hand out of radios?

Mike

User avatar
rustynswrail
Posts: 646
Joined: Thu Mar 11, 2010 10:18 pm
Location: Blue Mountains

Re: VIC MMR tracking with DTS96/PRO96

Post by rustynswrail » Fri Dec 09, 2011 12:27 pm

Mike Alpha wrote:So where are we at with interoperability between NSW GRN and Vic MMR? Or is it still a bit too soon? If we had a - dare I mention it - Cyclone Tracey scenario now, are there common liason TGs accessible to both systems or will there be a hand out of radios?
Mike

Mike,

Dare I say at the risk of ridicule, UHFCB is looking real good for interoperability. The concept behind common communciation systems across the states is dead. Australia when it comes to many things is not a commonwealth, but a collect of states and territories with very parochial views. We could not agree on rail gauge or traffic laws to mention but a few. Why should radio be any different.

R
Amateur Radio, when all other cures for insomnia fail!

Scotty
Posts: 739
Joined: Sun Dec 20, 2009 2:50 am
Location: Sydney and surrounds

Re: VIC MMR tracking with DTS96/PRO96

Post by Scotty » Fri Dec 09, 2011 2:34 pm

Mike Alpha wrote:So where are we at with interoperability between NSW GRN and Vic MMR? Or is it still a bit too soon? If we had a - dare I mention it - Cyclone Tracey scenario now, are there common liason TGs accessible to both systems or will there be a hand out of radios?

Mike
Cyclone Tracey scenario happening again... there have been worse disasters in the last 12-24 months in Australia and Internationally in which emergency services have come from all over the country (and overseas) to assist, and comms were not an issue raised at any of these. The recommendations coming from Cycle Tracey are almost 30 years out of date and are no longer relevent, being made when command/control senarios were non-existant and technology was not anywhere near advanced as now (ie most radios were still programmed with crystals and mobile/satellite phones where as good as non-existant). Times have well and truely changed in both distaster response protocols and technology.

The idea of 'common communication systems' serves no purpose. There is no need for the majorty of services in one State to be able to operate on the radio systems in another State. Several times in last 12-24 months alone emergency services from different states have travelled to assist in many different states, even overseas, and have not had a problem with comms.

Liasion between services is now done further up chains of command meaning the people on the ground don't need the ability to talk with one another.

Post Reply