New system for OCPD-ask questions here

[freqscout]

http://www.wirelessweek.com/article/CA522586.html
From the looks of it some of the routers will be connected directly to wireline service points. This link is the news release on the project and it dosn't mention anything else such as a Motorola Umbrella system or anything like it which would serve as a major data gateway other than the Tropos units. The way it looks the cars will get the Tropos 4210 mobile data cells also. I am sure that officers will have limited web browsing capability if any. The city is looking at opening the inner part of the wireless network for public access to wifi network service. So apparently it is possible that the network has the capability to carry the internet in addition to the Pub Serv information.

http://www.tropos.com/pdf/EMS_datasheet.pdf
This is the overall setup datasheet for their projects and they show the 5210's as the access points with others linked to them.

http://www.tropos.com/products/pdf/4210_datasheet.pdf
This is the mobile unit. Apparently the mobile unit can act as a router to another router itself.

 

[habpatrol]

Does this new OKC system have a permanent patch to the State system or what has been done to ensure interoperability? I saw on the news that they are supposed to be able to communicate with any and everyone on this new system.

Also do you know if the new radios for OKC PD are programmed with the NPSPAC I-TAC frequencies?

Thanks

 

[dstew67]

Does this new OKC system have a permanent patch to the State system or what has been done to ensure interoperability? I saw on the news that they are supposed to be able to communicate with any and everyone on this new system.

Also do you know if the new radios for OKC PD are programmed with the NPSPAC I-TAC frequencies?

Thanks

The patch is sort of automatic. The (OKC PD) user has to switch to a talkgroup which is tied to the appropriate HP talkgroup. You can see the available talkgroups here. There are potential issues with this setup though, some of which has been discussed here. When a user switches to one of these "mutual aid" talkgroups, it effectively ties up a portion of the OKC system until the user changes back to another talkgroup, unless that user is simply scanning one of these talkgroups.

The new radios are programmed with the NPSPAC frequencies. They can transmit on the inputs and thus use the repeaters, or they can transmit in talkaround which will not go through the repeaters.

 

[mule_tail]

habpatrol,

Yes, the OKC system will have a permanent patch to OHP Metro, Rural, and Capital Patrol. Also, it will have permanent links to 5 of the State's Regional Mutual Aid (RMA) talkgroups. These will all show up as talkgroups on the Police and Fire radios and will not require dispatcher intervention.

Yes, all 5 NPSPAC Conventional channels are in the OKC system, with all 5 repeated at 4 sites.

 

[mule_tail]

The patch is sort of automatic. The (OKC PD) user has to switch to a talkgroup which is tied to the appropriate HP talkgroup. You can see the available talkgroups here. There are potential issues with this setup though, some of which has been discussed here. When a user switches to one of these "mutual aid" talkgroups, it effectively ties up a portion of the OKC system until the user changes back to another talkgroup, unless that user is simply scanning one of these talkgroups.

The new radios are programmed with the NPSPAC frequencies. They can transmit on the inputs and thus use the repeaters, or they can transmit in talkaround which will not go through the repeaters.

Actually the idea that selecting a talkgroup tied to another system like OHP will "tie up" the system is incorrect. It has no more impact than the traffic on any other talkgroup. The interface will only assign a channel on the OKC talkgroup when there is traffic on the other side of the interface.

 

[woodyrr]

OK. By switching to a talkgroup on their radios, users of the OKC system can "reach out and touch" the OHP as an example. Conversely, how does OHP reliably and certainly initiate a radio contact with an OKC user on the OKC system outside of hoping that an OKC radio is set to scan and someone happens to hear the call? The same question applies to all of the mutual aid talkgroups (MWC, Del City, etc).

 

[mule_tail]

What data speed is that going to run at? I don't know what speed ProVoice is, but I would imagine it's around 9600 bps. I've heard of 19200 bps over digital voice channels, and I think I read somewhere that you can get up to 96000 bps on a APCO-25 signal with some new data mode. I know P25 has a low speed (around 88 bps) data sub-channel that is always going. This is not used for anything that I know of yet. Does ProVoice do this also? Can one "read" a ESN from this data? Is ProVoice modeled at all like P25 (other than being AMBE vs IMBE)?

The data speed is 9600 bps per channel. So, the more channels that are available, the larger the aggregate bandwidth. While this data rate is not what you want to use for applications demanding high bandwidth, it is more than enough for inquiries, CAD transactions, and AVL updates. As a benchmark, consider the current Police and Fire MDTs (all but a handfull) operate on a single 800 MHz RF channel at 4800 bps.

The radios being used for secondary "umbrella" coverage are not ProVoice radios. They are M/A-COM 500Ms with a data option.

 

[mule_tail]

OK. By switching to a talkgroup on their radios, users of the OKC system can "reach out and touch" the OHP as an example. Conversely, how does OHP reliably and certainly initiate a radio contact with an OKC user on the OKC system outside of hoping that an OKC radio is set to scan and someone happens to hear the call? The same question applies to all of the mutual aid talkgroups (MWC, Del City, etc).

Well, OHP will be adding talkgroups to their radio template that correspond to OKC's primary dispatch talkgroups. So for example a trooper will have OKC Hefner on their radio which will be tied to OKC's Hefner talkgroup. They can scan it, or switch to it and key up.

More difficult for jurisdictions with conventional systems. There is, however, a group of individuals representing many of the metro area jurisdictions and the State who are working on ways to address this.

 

[woodyrr]

Well, OHP will be adding talkgroups to their radio template that correspond to OKC's primary dispatch talkgroups. So for example a trooper will have OKC Hefner on their radio which will be tied to OKC's Hefner talkgroup. They can scan it, or switch to it and key up.

More difficult for jurisdictions with conventional systems. There is, however, a group of individuals representing many of the metro area jurisdictions and the State who are working on ways to address this.

Thank You, Mule Tail

 

[mule_tail]

Thank You, Mule Tail

Glad to help.

 

[mule_tail]

Right. I think I remember someone mentioned that they relayed traffic ..

Thanks for posting that link to the OEM's website. This tidbit kinda sorta answered my question:I guess my real question is if system has several feed points to the mesh or just one?

What type of throughtput can a user expect? Can they surf the web? How much latency does the network have esp. out on the fringes?

ps .. mam1081 - check your RR IM.

The part you are asking about (and the part missing from Tropos' literature) is the backhaul. The City is using Motorola Canopy to aggregate (point-to-multipoint) and backhaul (point-to-point) the stream to multiple fiber connections, tying the wireless to the wired LAN. OKC built upon other projects (outdoor siren poles and radio towers) to create the distrubuted mounting assets for the backhaul.

I noticed some of the comments regarding the funny looking antennas on the new black and whites. Can't disagree. However, >1 mbit at 70 MPH buys a lot of ugly. Remember, other posts have noted that the vehicles will be equipped with the Tropos 4210, which is a full router participating in both the fixed mesh and the mobile mesh.

 

[crayon]

Thanks for the info mule_tail.

Dare I say that I am starting to warm up to the new system?

Aside from the ProVoice aspect of it ... of course, it seems like some really neato engineering has taken place.

 

[mam1081]

Was the Tropos price quote lower than an all-out Canopy system?

I have used a Spread Spectrum 900 MHz iNet radio, with towers linked with Motorola's canopy system, and it works well. We slowed our mobile units down to 256k for better range and less errors. This left the "bottleneck" at our offices that were feeding the iNet routers the network at DSL or Cable modem speeds. The far outlying areas used the Canopy links for the towers.

Ours being on 900 MHz seemed to work better than the local city's 2.4 GHz 802.11b WiFi system (officers complained they had to sit right under the AP to get on the network - but then they didn't have the beasts that OKC will have). I don't know if it was the antennas or what, but it certainly did work well. It will be interesting to see how it all works together.

 

[mule_tail]

No Canopy proposals. Initial proposals included wifi at hotspots only. Didn't make sense to spend that much on 19.2kbps systems with hotspots. Pure mesh had too many hops. Speed loss for every hop on the way to the LAN. Canopy was introduced as a good way to distribute backhaul geographically and reduce hop count.

 

[KD5YKM]

I honestly think that KK5FM should be THE go to guy for setting up repeaters in the OKC area. rumor has it he's got one of the largest antenna farms this side of Stillwater.

 

[K5MAR]

I honestly think that KK5FM should be THE go to guy for setting up repeaters in the OKC area. rumor has it he's got one of the largest antenna farms this side of Stillwater.

Gotta be carefull about believing rumors!

BTW, the avatar you chose doesn't match your name very well, that could start a few rumors too! :lol:

Mark S.

 

[KD5YKM]

Gotta be carefull about believing rumors!

BTW, the avatar you chose doesn't match your name very well, that could start a few rumors too! :lol:

Mark S.

You're correct....I'm sure a few people's eyebrows were raised with my avatar I'll change it when I find a more appropriate one. HONEST!

 

[Dog]

Thanks for the info mule_tail.

Dare I say that I am starting to warm up to the new system?

Aside from the ProVoice aspect of it ... of course, it seems like some really neato engineering has taken place.

I don't know all the ins and out of the system, i know very little actully when i read through here. lol I have been in the control room at the radio equipment. I am installing radios in almost all the vehicles besides police and fire (example, animal welware, transit, parks and rec., water deprt., air port). It is an amazing system but there are a lot of bugs that need to be worked out. And a ton of radios will have to be reprogrammed.

 

[scmadhatter]

So will my scanner become a paperweight soon then?

 

[K5MAR]

Only for monitoring OKC traffic. There is still alot to listen to, OHP, Norman, Edmond, weather, aviation, etc.

Mark S.