Switching from OpenSky to P25 ??

[Tim]

Greetings All,

The agency I work for is currently converting to an OpenSky radio system and we are having numerous problems. There was a suggestion to possibly change from OpenSky system and convert to a P25 trunked radio system. Currently, the mobile and portable radios we are using (P7200/P7300) can handle P25.

The radio vendor told us this was not possible because everything except the portable radio antennas would have to be replaced. I know that the backbone equipment would have to be replaced (controller, etc), but would they have to replace portables and mobiles..also? Couldn't they just get the backbone P25 system running and then OTA/software upgrade the portables/mobiles?

Can anyone shed some light on a transition like this?


Tim

 

[EnidPuceflange]

Well, the radios do indeed support P25 trunking but they need to be feature encrypted for that and that almost certainly hasn't been done, so that is one obstacle.

Opensky is significantly more efficient in terms of frequencies - there are either 2 or 4 talkpaths per 25kHz channel, where P25 trunking provides 1 talkpath every 12.5kHz (or every 20/25kHz at 800MHz) so you have significant capacity issues, and will need more frequencies (and thus channels on combiners/multicouplers, etc) and the coverage maps will need to be redrawn.

Finally the base station infrastructure is different between OpenSky and P25 trunking, although the backhaul and network management systems are common.

It looks to me like your agency would be better served getting OpenSky to work right (it does, but it needs care in setting it up), rather than ripping it out and dropping the bill on your local taxpayers.

 

[greenthumb]

I think what they meant was that everything on the back end/infrastructure would need to be replaced except, perhaps, for the base station antennas. If your portables and mobiles are 7200/7300 series, those do support P25. However, the 7200 series was short lived and had issues all of their own.

Given the issues that Milwaukee has been experiencing with voice over OpenSky, I would hope that the vendor would step up to the plate and make things right. They risk losing a big customer if they don't.

 

[Mweiher]

Sure, Tim -

Just put some dollars into expanding the currently being installed county P25 system and join up! When I left Milw Co, they were experimenting with one or two of MPD radios at M2W to put the county system on them to test them. Not sure what happened since I left, but surely they are onto something.

Yes, Harris is correct, if you want a HARRIS P25 system it would require $millions in FNE hardware - but NOT if you were willing to merge with every other law enforcment agency in the county.....

(I mean, even though Greenfield wasn't on our shared system, we had good links and talk groups on each others' radios - so interop capabilities were excellent.) I KNOW Tosa PD would LOVE it if MPD came on the county P25 system with all the troubles on your border. Not only that, but think about how it might have worked opening night of State Fair with WAPD????

The MC system has everyone else shared (or linked) and coverage county-wide is excellent. Why on earth would MPD want to remain an island? I could never figure this out. There was always automony of systems when linked - MPD would still control their users/system, but still they preferred to remain an island.

ADDED AFTER EDIT ___________________________________

While we're talking about merging P25 systems, I hear through the grapevine that WKSH Co is stirring the pot to go P25. When I was Radio Admin at Milw Co and Bud was our CIO, we often talked about merging radio systems with WKSH Co and having one huge one. We dreamt of the day when there would be a region-wide system. It made beautiful sense. Then Bud left and I got too burnt out with rebanding to pursue the issue further. (Notwishstanding the radio knowledge -or lack thereof- of the new Radio Admin at Milw Co.)