KHP hating on P25.

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captlpol
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KHP hating on P25.

Post by captlpol » Sun Apr 06, 2008 11:19 pm

The Kansas Highway Patrol seems to be hating on P25.

Here's why they don't work in the metro:

Troop A uses three radio systems:

#1 - Piggy-backed off of the Johnson County Sheriff's Office analog trunk
#2 - Piggy-backed off of KCKPD's analog trunk
#3 - Digital P-25 system (new and NOT so improved)

The Leavenworth & Miami County troopers use the digital system. The Johnson & Wyandotte County troopers uses the JOCO trunk primarily and the KCK trunk secondary, depending on where they are in WYCO. Dispatch simulcasts across all three systems. If the radio is on one system, you can't hear anybody besides dispatch on the other system. So when on digital, you won't hear JO/WY troopers, just LV & MI.

The MDUs run off of the digital system. Are you beginning to see a problem yet? If not, here it is:

The in-car radio has to be on the digital system in order to run tags, use the MDU for anything other than as a regular computer, etc. The radio is the modem basically and it has to have a connection with the radio.

Problem #1 - If the in-car radio is on digital, you can't hear your partners in JO/WY. You will only hear what dispatch repeats back. So for all you know, somebody could be a mile down the road from you trying to stop a vehicle that is failing to yield, fighting with someone, out checking a drunk driver, needing another car for a search, may have just pulled up on a crash, etc, and you won't know it until dispatch repeats it back IF THEY DO.

Problem #1a - The in-car radio is on digital for the MDU, so you have to keep your portable radio on the analog trunk to monitor your partners.

Problem #1b - Obviously the portable radios don't have as great of coverage as the in-car radio, so if you get further north (say, north of I-70), you can't get out on your portable on the JO trunk and it's hard to hear too, so you have to switch to the KCK system on your portable. Now you're back to problem #1, not being able to hear the majority of your partners on the Johnson trunk.

Problem #2 - The digital system lacks greatly in coverage. Northeast of I-635 on I-35, it's nothing but garbled crap. East of about US-69 on I-435, same thing. You can't hear anything, you can't make out anything anybody is saying and you surely can't transmit. You get a long low, "out of range" tone when you try to transmit and the radio shows, "OUT OF RANGE". There are plenty of places when driving around that the radio will start making that low out of range tone, so obviously if you got into something, you'd be without a radio. The digital system is like digital TV - it's either on or off. At least with analog, you might be able to make out a scratchy transmission or a weak transmission cutting in and out, but with digital, it's pretty much all or nothing.

Problem #3 - KDOT has said it's basically NEVER going to get any better. They need to put a tower on top of KU Med for the northeast part of Troop A, but for some reason that's not possible right now. I don't know if it's funding (probably) or butting heads with KU Med or what the deal is. Speculation on my part, but I assume it's mostly funding among other things.

Problem #3a - This MDU thing was KHP's, not KDOT's. From the looks of it, there was not adequate research put into it (e.g. - contacting the local agencies in KC to see what has worked and not worked for them, contacting MOSHP who has had MDUs for years or KCMOPD for the same reason). Those agencies have since switched from using the radio for the MDU connection to wireless cards, which works much better.

Problem #4 - On the KCK trunk, you can scan KCKPD and switch over to their channels to go direct with them if necessary, which the helicopter does quite frequently. On the JO trunk you can monitor inter-city (a mutual aid type channel for the Johnson County PD's). On the digital, you can't do that. All you get is KHP. You're kind of out of the loop on digital.

Problem #5 - The volume is really weird on the digital. The troopers are very quiet but dispatch will blow you out of the car. It's a constant up/down volume control for almost EVERY transmission. When driving fast with wind noise and sirens in the background, it's very difficult to hear anything, even with the volume on max.

Problem #6 - When using the MDU to run something, VOICE transmissions take prescedence over DATA transmissions. So if you run a tag then somebody talks on the digital, your tag gets pushed to the back burner. Every time somebody talks, your tag keeps getting pushed back down the line until all the voice data is finished. It's annoying and defeats the purpose when you can just pick up the mic, run the tag and get it back within seconds, all the while without trying to type and read a computer screen as you're driving 70 mph down the interstate.

So there you have it. That was a long explanation, but that's pretty much the deal in a nutshell. These problems aren't necessarily in a specific order or order of importance, just as they came to me while I was typing.

Furthermore, the comments contained herein are only my opinions based on my experiences and limited technological knowledge of the radio systems. Do not confuse my opinions for anything besides one "end user's" opinions.
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escomm
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Re: KHP hating on P25.

Post by escomm » Mon Apr 07, 2008 12:06 am

P25 is a waste of money
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Re: KHP hating on P25.

Post by motorola_otaku » Mon Apr 07, 2008 12:24 am

Using the voice radio as a modem is pretty stupid (afaik, no one in this half of TX does that), but the rest of those issues are fixable. A 3-way console audio patch across all 3 disparate systems is plenty do-able with "tolerable" audio quality until they can get their digital coverage issues straightened out.

Honestly, I was surprised to hear that KHP wasn't using lowband. Kansas strikes me as one of those states where LB would be king. :baby:
escomm wrote:P25 is a waste of money
The biggest mistake our government ever made in regards to radio communication was allowing public safety agencies to use 800 MHz. Commercial users should've been forced to move up to 800/900 MHz 25 years ago, and public safety/government given carte blanche use of VHF and UHF. Had that happened, none of the problems we see today would exist. The commercial sector is much better suited to overcoming and adapting to spectral handicaps.
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Re: KHP hating on P25.

Post by escomm » Mon Apr 07, 2008 1:33 am

No the biggest mistake the gubment made was allowing Nextel to buy up 800/900MHz and then believing Nextel when they said "we'll pay for the migration"
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Re: KHP hating on P25.

Post by Radio_Cowboy » Mon Apr 07, 2008 9:06 am

motorola_otaku wrote: Honestly, I was surprised to hear that KHP wasn't using lowband. Kansas strikes me as one of those states where LB would be king. :baby:

They used to. So did KDOT. I have a ex-KDOT lowband X9000 (with VHF VRS) somewhere in my stash.
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Re: KHP hating on P25.

Post by motorola_otaku » Mon Apr 07, 2008 10:05 am

escomm wrote:No the biggest mistake the gubment made was allowing Nextel to buy up 800/900MHz and then believing Nextel when they said "we'll pay for the migration"
Case in point: had PS not been allowed access to 800 MHz in the first place, then Nextel's iDen faggotry would've been the sole problem of the commercial mobile radio community. Let their lawyers duke it out in court, while PS/CI users get exclusive use of spectrum that Just Works for high-site/wide-area systems.
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Re: KHP hating on P25.

Post by escomm » Mon Apr 07, 2008 11:47 am

Actually it doesn't work when there's PS only spectrum, in LA PS has 12 megs of UHF T-Band dedicated to PS, plus another 25 or so channels of exclusive use 470-476 spectrum (470 pairs have sold for up to $500k each recently). Their spectrum is quite mismanaged (LAPD and LA Sheriff's do NOT need 120 channels+ between them) and there should be greater refarming of frequencies based on geographical presence. Don't even get me started on ICIS and the use of so-called PS freqs by agencies such as animal control, street lighting, admin services....

There is much fighting over pieces of the pie and there really isn't any PS spectrum left in SoCal, and this does not even take into account the myriad agencies on VHF (LA County Fire for example) or 800MHz (LAFD, who thankfully never bought into Nextel's bullshit)

Also keep in mind that many agencies were already on 800 long before Nextel came along. Who could have foreseen in the 80s that the FCC would allow a carrier would basically buy up two fucking blocks of two-way spectrum and use it for their shitty cellphone service?
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