P25 USAD programming

[citabria]

Now that is very interesting - How do you get that out of a 996?

I wonder why its broadcasting info about other bands?

[citabria]

Having a look back those bandplans seem like 4/5 are gibberish. I'll get a capture of a P25 control channel tonight and see whats in there.

Cheers,
Matt

[JAFO]

Im confused - band plan 5? wouldn't it just start at plan 1 and work up?

Well this is the band plan that Unitrunker, Pro96Com and the 396/996 decode from the CC data stream.
1. 851.006250 - 6.250
2. 762.006250 - 6.250
3. 851.012500 - 12.500
4. 762.006250 - 12.500
5. 412.475000 - 6.250
6. 420.012500 - 6.250

Obvioulsy all aren't relevant for the P25 GRN, so do we use all or just no 5?

Mike

[/quote]

Having a look back those bandplans seem like 4/5 are gibberish. I'll get a capture of a P25 control channel tonight and see whats in there.

Cheers,
Matt

Matt,

I am in the same boat as Mike, my 996 just automatically comes up with those same band plans.

[citabria]

I agree thats what's coming over the control channel Grant - I see the same thing on my 996 and PRO96COM.

It just makes no sense to have two bandplans starting at 762.0062500 but with totally different spacing.

I suspect these are the American defaults that come programmed into the P25 controllers, with the exception of bandplan 5 and possibly 6. needless to say, Its a fair bet that /\/\otorola OZ are learning this new system too as they're implementing it.

[soupbones]

I think your right there Matt. Or it probably something the techs have not got around to changing. Would the GRN still use the same base frequencies as the analogue GRN, but different step? I thought they would have to as this is the band they have been allocated in NSW.

Anyway I received some files off JAFO and will try them out tomorrow probably. I have not had a good look at them yet, but he has mentioned that he put the old analogue TGs in them till some of the new ones are worked out. Not sure why you would do that, but I am wondering if for some reason the USAD software is not accepting the TG format I used in mine?

[Longreach]

i dont know if its any help but i let my PSR500 automatically find the bandplan and has worked.

[citabria]

I was thinking about something soupbones said to me the other day while I was on the way to work and it reminded me that P25 trunking supports two types of operation.

1) Explicit CC trunking - This does not use bandplans - instead the control channel transmits the exact frequency that the MR (mobile radio) is meant to tune to. This gives the network managers far more flexibility, and I suspect this is the type of trunking that a brand network like P25 GRN would be using. This means that the bandplans don't matter anyway and would explain why the bandplan information we are decoding from the CC to be a bit strange.

2) Implicit trunking. This is the old style of channel control like /\/\'s Type II trunking used. There is a bandplan that maps frequencies to hexadecimal channel numbers which are then transmitted over the CC. With this type of trunking a bandplan is obviously required.

I think the next step in solving this one is to determine what type of trunking the P25 GRN is using - this will tell us if we can ignore the bandplan when programming our scanners. I know the GRE PSR's have an option when you program a P25 trunk system - you either program the system as explicit or implicit.

Cheers,
Matt

[JAFO]

but he has mentioned that he put the old analogue TGs in them till some of the new ones are worked out. Not sure why you would do that,

In short - Because I am lazy and I know down the track I could not be bothered redoing all the Alpha Tags again, so figure it would be just as easy to keep all the current system TalkGroup Alpha Tags and change each TalkGroup ID's to the new P25 ID's as we work out which one is what.

Already know TG:10101 is for NSWFB, just have to wait and see if it stays active and then what NSWFB Channel it for, just have to change the TG ID then and not the Alpha Tag.

As I said, I am lazy, I know its sad.

[JAFO]

The Band Plan is not as erratic as NSW new P25, but even Victoria’s MMR Band Plan is a little surprising with some Frequencies to.

851.006250 - 6.250
000.000000 - 0.000
418.100000 - 6.250
420.012500 - 6.250
421.262500 - 6.250
422.262500 - 6.250
425.262500 - 6.250
465.075000 - 6.250

[citabria]

i dont know if its any help but i let my PSR500 automatically find the bandplan and has worked.

Yes - It doesn't mean that the system is actually using those bandplans when it hands out channel grant information to the subscriber radios.

Another forum member has graciously loaned me a PSR500 which is awesome when used with PRO96COM - it lets you look at the raw data going over the control channel and see if the system is implicitly or explicitly handing out channel info.

JAFO - as my previous posts point out - the bandplan might be totally useless and not even configured if the system is explicit.