NSW Police Broadcasting On GRN

[citabria]

I don't see the problem. The Police already have P25 compatible bases that are supported until 2020. All thats required at each police site, is a PSC9600 controller and V.24 Synchronous serial links - oh and maybe another repeater for the control channel(s)

They can even still use their existing frequencies - the Vic MMR does exactly that - the 420MHz stuff is for all the GRN users except the police, and the police radios run trunked by listening to a 420MHz control channel and then get handed over to a dedicated, trunked 467-469MHz frequency.

Motorola's current 7.x functionality provides for 16 bases and offset ranges, and from what I see the NSWGRN only has the first 6 base and offset ranges configured (out of a total of 16) and out of those 6, only 2 of them are in active use. Technically theres nothing stopping them from adding a base and offset range starting at 467.850, with 12.5kHz steps...

Cheers,
Matt

[Bigfella237]

True, but those 'converted' sites would need to place heavy restrictions on which talkgroups are allowed on each site?

In a scenario where you have the conclusion of a long pursuit in a location covered only by a one base site, you might have cars from three or four different channels (and a couple of back-channels thrown in) all trying to affiliate to different talkgroups on a single repeater, which would obviously be a disaster communication-wise? I guess once trunked they could assign tactical talkgroups and direct everybody to them for specific incidents, but you know that talkgroup is gonna light-up on every base across the city anyway with everybody wanting to listen?

The only real benefit (at least to begin with) is they will have the added coverage of existing GRN sites, which may free up some PF infrastructure to be relocated?

Either way it will be interesting, we just need to keep an eye out for new peers popping up on existing sites... the 2015 deadline is only a matter of months away now!

Andrew

[citabria]

Andrew,

Yep - kind of - they would need to use the existing methodology of one TG per geographical region (Are they still called LACs?) for it to work efficiently

However these types of things are driven by political pressure, and by having dedicated police only bases being controlled by the GRN keeps everyone happy - the police can't say they have lockouts, because theres just as much bandwidth as before and it also ticks the "politicians" checkbox that says "police must migrate to GRN"

Of course, no one really knows how these things will pan out. and I don't believe the NSWGRN has exhausted P25 technology to the fullest - for example, There are areas where LSM (CQPSK) Simulcast can be used which could make a single site cover a much larger area without paying more in RF channel fees, and then theres the migration to Phase 2 which creates 6.25e kHz (6.25kHz equivalent) channels by incorporating TDMA with some funky new modulation schemes that squeeze more out of a given channel..

As you say - interesting times ahead, and I don't think the network managers even fully know what they're going to do with it yet

Time to sit back with beer and popcorn and see what happens

[Bigfella237]

Of course the system infrastructure is almost inconsequential to the upgrade to TDMA, it's replacing a fleet of thousands of radios that will take both time and money (with only the APX family being capable of Phase II of course), last I heard there are still ASPs and XTS3ks floating around, but I guess they would mostly be found in country areas these days?

All I can say is, I'm glad it's not me doing their end-user radio training!

There have been numerous times where I've heard someone can't figure out how to change to a different a zone or even select another channel on the newer radios, how are they going to deal with TPTs and busies and denials etc.?

The VICMMR (and the QLDGWN too by the looks of it) certainly seem to be miles ahead in terms of their use of LSM for in-building and low-power (portable) coverage, although I guess you could argue too that neither have such a significant underground rail service to cater for, which makes their job a lot easier.

I just hope that eventually those dedicated PF sites get expanded so everybody gets the coverage, but I guess it all comes down to dollars, maybe they could sell some of Barry's wine collection to fund the upgrades?

Andrew

P.S. Beer and popcorn... hmm

[techman]

Budgeting is high in the list but band plan changes are also going to cause someone some pain

The link below is interesting reading
http://www.acma.gov.au/webwr/radcomm/fr ... rgo_50.doc
http://www.acma.gov.au/Industry/Spectru ... nning-acma

Basically they need to move bands at some point in the next 18 months so why not move onto the GWN and outsource the move issues - Police are making a smart move, get onto gwn and then wait for them to make plans to move bands by end of 2015 before acma revoke the licenses.

a

[techman]

Of course the system infrastructure is almost inconsequential to the upgrade to TDMA, it's replacing a fleet of thousands of radios that will take both time and money (with only the APX family being capable of Phase II of course)

Tait has Tx5400 series P25 phase II radios and repeaters out for sometime, Simoco should be working on there solution plus there are other options from the US which are certified except if they are running some moto restricted free lockin feature.

From memory I have seen tv shows where the nswps are using a mixed fleet of radios - not sure if that is still the case.

Also Qld - wait and see what occurs, there has been discussions around other OS forums other large P25 phase II installations in the US have had issues and gone back to phase I - not sure the exact details. At the end of the day, someone bureaucrat up here will be a hero if it all works or the vendors are going to pay dearly if it fails or has issues.

[Scotty]

Basically they need to move bands at some point in the next 18 months so why not move onto the GWN and outsource the move issues - Police are making a smart move, get onto gwn and then wait for them to make plans to move bands by end of 2015 before acma revoke the licenses.

Law enforcement agencies (ie, police) are excluded from the embargo according to those documents, so there is no need or incentive in that sense to move to the GRN as the embargo won't effect them.

[Scotty]

...last I heard there are still ASPs and XTS3ks floating around, but I guess they would mostly be found in country areas these days?

Plenty of XTS3k's floating around in metro areas, especially during large events.

[Bigfella237]

Thanks Scotty, hard to believe that 3000's are still in use, they must be like 15 years old by now!

My assumption was that newer radios would be directed toward metro and the older radios re-purposed to country areas, but I guess there's a bank of spare radios somewhere that still get dragged out when needed?

Andrew

[techman]

Basically they need to move bands at some point in the next 18 months so why not move onto the GWN and outsource the move issues - Police are making a smart move, get onto gwn and then wait for them to make plans to move bands by end of 2015 before acma revoke the licenses.

Law enforcement agencies (ie, police) are excluded from the embargo according to those documents, so there is no need or incentive in that sense to move to the GRN as the embargo won't effect them.

Not to sure about all states but in Qld some govt users operate outside of the assigned 2.4mhz allocation but still in 450-470mhz band (ambo's and fire dept in some locations) as outlined in the doco - In NSW, it may not effect GRN but still could have an impact onto non GRN/police users.