Highway Patrol and Low Band

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btritch

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I have a small question, I listened to the Missouri Highway Patrol last weekend, And I noticed that dispatch and troopers both used different frequencies which I was aware of, However, I noticed that I couldn't hear all of Troopers, just the dispatch most of the time, I am just wondering if I can't hear the troopers but I can hear dispatch, How can dispatch hear the cars all the time? I mean, how is it possible?
 

btritch

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That's true, I was just using a mobile, They're one of a few agencies that I know of that are even still using low band. Most agencies have already gotten off of that system, When do MHP plan to change to something else? Or do they?
 

mtindor

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There are various reasons. One or more of the following is likely:

DISPATCH likely has access to multiple receiver sites - They use a voter (there is a better word for it) that measures the signal quality of multiple recievers and then the dispatch hears the best signal. Plus, like the previous poster mentioned, they usually place the receiver sites in strategic locations that are fairl high and unobstructed. They'd also be using gain antennas that perform better on receive. Plus, their receivers are likely a helluva lot more sensitive than what you are using to listen to them.

And, I don't know if it's the case with this particular highway patrol, but they may be using split frequency (where the cars are transmitting on freq 2 and receiving on freq 1 while the dispatch is transmitting on freq 1 and listening on freq 2). This woudl be similar to a repeater in that different transmit/receive freqs are used, but unlike a repeater in that there is not a site specifically retransmitting the mobile transmissions via a high location back out on another frequency.

Mike
 

kpoe_28

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That's true, I was just using a mobile, They're one of a few agencies that I know of that are even still using low band. Most agencies have already gotten off of that system, When do MHP plan to change to something else? Or do they?
The car's are retransmitted via repeater one located just east of Kennett input freq is 42.32 and output is 456.275 and is beamed to Poplar Bluff with a beam antenna. You just almost have to be right in line to hear them on the 456.275 freq. If you have a good outside antenna you should hear the state car's for Dunklin and Pemiscot County's on 42.32.

Kevin
http://www.geocities.com/kpoe_28
 

shaft

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Troop C, transmitts and receives on 1 frequency depending on the zone. Even the car to car chatter is on the same freq as the dispatch but only on low power.

Here in Troop C land, if you can hear the trooper talk to dispatch, you can figure they are within 15 miles of your location using a mobile antenna. If you can hear 2 troopers talk to each other, slow down, they are within a couple miles .
 

btritch

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The car's are retransmitted via repeater one located just east of Kennett input freq is 42.32 and output is 456.275 and is beamed to Poplar Bluff with a beam antenna. You just almost have to be right in line to hear them on the 456.275 freq. If you have a good outside antenna you should hear the state car's for Dunklin and Pemiscot County's on 42.32.

Kevin
http://www.geocities.com/kpoe_28
I have a scantenna, So if I were to enter them I'd have to enter the 42.32 frequency instead of 456, Right? That's why I never heard anything in this area, I had the ones for PB entered..

456.27500 WGT388 F Troop E - Mobile Relay (Bakerville - Pemiscot County) FM
456.47500 WGJ854 F Troop E - Mobile Relay (Benton - Scott County) FM
456.52500 WPMH595 F Troop E - Mobile Relay (Knob Lick - St. Francois County) FM
460.25000 F Troop E - Mobile Relay (Doniphan - Ripley County) [No License?] FM
42.92000 42.22000 KAA270 BM 173.8 PL 50 Troop E North Dispatch FM
42.92000 KA5824 M 173.8 PL 51 Troop E North Car-to-Car FM
42.22000 KA5824 M 173.8 PL 52 Troop E North Cars RX FM
42.94000 42.32000 KAA270 BM 173.8 PL 53 Troop E South Dispatch FM
[I]42.94000 KA5824 M 173.8 PL 54 Troop E South Car-to-Car FM
[/I]
42.32000 KA5824 M 173.8 PL 55 Troop E South Cars FM

42.00000 KA5824 M 186.2 PL 59 Statewide Car-to-Car FM

154.66500 KA5824 M Tac-2 Troop E: Tactical 2 FM
154.93500 KA5824 M Tac-1 Troop E: Tactical 1 FM
154.92000 KAA270 M CSQ Detectives/Rural Investigators FM
155.37000 KAA270 M CSQ Point-to-Point FM
155.47500

The one's in BOLD are the one's you specified, However, The ones underlined and intalicized also say E South, Are they entered to?
 
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mjthomas59

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I think there may be some misinformation going on in this thread, that or i'm just not following correctly.

First off MSHP is a non-repeated system in all the troops that i've been in. 2nd off, the dispatch centers have antennas which are hundreds of feet in the air, thus they can hear everything even though we can't. Lowband, by the physics of the band, carries further or covers more distance than say 800mhz thus you don't need that many receive sites to cover such a large area. 3rdly, The remote towers are only used when the troopers are close to them, just by monitoring 1 remote tower on UHF doesn't mean you will hear every trooper who is transmitting within that troop. The towers are setup on the edges of each troop to help cover the deadspots, and I don't believe these remote towers are receiving from lowband frequencies, if i recall correctly they are receiving UHF frequencies and then sending them via highly-directional antennas back to the dispatch center. I've never got real in-depth with all the radios that they have in the troopers cars, but it is pretty ridiculous. Atleast 1 lowband radio, 2 VHF-HI radios, a mobile repeater(usually moto pac-rt's) plus CB and who knows what else. According to the DB they also have UHF radios to communicate with the remote towers.

Further, as btritch noted, there are output frequencies used by dispatch to talk to troopers, there are input frequencies used by troopers to talk to dispatch, and then the troopers will also use the output frequency as a "talk-around" or "car to car" frequency. They will also use 42.00 as a car to car channel and for speed enforcement, as well as Law Mutual Aide, Sheriffs Net, and several other VHF-HI band frequencies to communicate. They also have access to most county radio systems assuming they are on lowband(which is only a couple at most) or VHF-HI.

I know there have been bids put in to put a new radio system in place although who knows when anything will be approved. I believe the FCC has set a 2013 deadline(was 2009) for all radios to be upgraded to digital format. I have also heard that testing has begun to figure out what kind of system will work best statewide, it sounds like it will be a multi-band system for the varying terrain across the state, but i doubt anyone really knows at this point. Regardless it would takes several years to erect towers, upgrade dispatch centers, and equip all troopers with brand new equipment. I wouldn't be expecting anything before 2010 personally, and even then they will more than likely still be using the old system along with the new. Last time I went through Illinois i was still picking up ISP traffic on lowband, and you still see some of their patrol cars with the lowband whips, and they've been in the process of getting their digital system up for quite some time.
 

semo

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The database is correct
Troop E North Zone cars base dispatch is 42.920. Cars reply to base on 42.220
Troop E South Zone (most likely the one heard in Ark.) base dispatch is 42.940. Cars reply to base on 42.320.
Troop E South zone cars use 154.935 MHz for car to car
Troop E South zone 42.000 MHz car to car
Troop E 42.020 MHz car to car to helicopter N873MP- heard on the scanner as 873MP
 

iamhere300

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I know there have been bids put in to put a new radio system in place although who knows when anything will be approved. I believe the FCC has set a 2013 deadline(was 2009) for all radios to be upgraded to digital format. I have also heard that testing has begun to figure out what kind of system will work best statewide, it sounds like it will be a multi-band system for the varying terrain across the state, but i doubt anyone really knows at this point. Regardless it would takes several years to erect towers, upgrade dispatch centers, and equip all troopers with brand new equipment. I wouldn't be expecting anything before 2010 personally, and even then they will more than likely still be using the old system along with the new. Last time I went through Illinois i was still picking up ISP traffic on lowband, and you still see some of their patrol cars with the lowband whips, and they've been in the process of getting their digital system up for quite some time.
No, no, no.

There has been NO bids to put a new radio system for the state. None. Ain't happened yet. Talks are
going on, ideas are being floated, consultants dealt with, but NO bids.

There also is NO requirement for anyone to go digital. Narrowband, but no requirement for digital. Further, narrowbanding does NOT affect lowband!
 

mjthomas59

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I appreciate being corrected on the bid part. I wish I could find the article I read where it stated that Missouri had eliminated several companies from the process and were going with either Motorola or (other company I can't remember).

I was told by our radio tech at work that all radios were to be updated to digital by 2013, he never said anything about narrowbanding. If that is the case it probably won't be until the middle of next decade before the statewide system is changed. I had inquired with him in regards to the 20 year old Midland radios we are still using in our patrol cars and when he thought they would be replaced. Now i'm scared i'll be stuck with these old dinosaurs for another 5 years. I finally broke down and bought my own Midland Olympian, which I believe will do narrowband, so I might just put it in my patrol car and dump the trunk-mount I've got now.

Also on a side note, I had heard that the Saint Louis City P25 trunked system was suppose to be the first building block for the statewide system, although again it seems that my sources for information aren't 100% reliable, and this was atleast 1-2 years ago when this was said.

Well I thank you for the correction. I would just like to see MSHP start repeating all radio traffic so it was easier to monitor.
 
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