Police Radio Setup

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sharamon

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I am just thinking one day, and the thought came to me (and I am in no way knowledgeable of radio networks) do law enforcement use some kind of repeater in the police car to help amplify what is coming out of their handhelds. So if the handheld can only transmit 10 miles, the repeater in the car picks up the signal and then amplifies it at another freq. Is this what happens? Or do police have separate systems in their car?
 

ab8sn

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Mobile Extenders

I am just thinking one day, and the thought came to me (and I am in no way knowledgeable of radio networks) do law enforcement use some kind of repeater in the police car to help amplify what is coming out of their handhelds. So if the handheld can only transmit 10 miles, the repeater in the car picks up the signal and then amplifies it at another freq. Is this what happens? Or do police have separate systems in their car?
Hey Sharamon

I know that others on here will be able to shed more light on this but yes some of them do. Here in WV some of our State Police are still on lowband VHF and they have handhelds that transmit on high VHF to the mobile extender in the car which retransmits to the lowband radio for further range. I think their handhelds are only a half watt or so and the lowband car radio is 100 watts. Hope this helps you a little bit

73s

Chad
 

sharamon

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Thank you

Do any of you know the situation for California Highway Patrol. And this system wouldn't be used for trunking correct?

Sharamon - way of the samurai
 

n5ims

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Do any of you know the situation for California Highway Patrol. And this system wouldn't be used for trunking correct?

Sharamon - way of the samurai
I can't answer the CHiP question, but these vehicular repeaters can be used for any type of system. What they do is simply add a repeater box to the normal car's radio. The handheld will transmit on another frequency to the repeater box in the officer's car and that will retransmit the signal out using their car radio. Basically what it does is extend their car radio's functionality to the officer's handheld radio. The handheld doesn't even need to be on the same band as the main system (there are advantages to them both being on the same band as well as having them both on different bands).

The handheld can be a very simple analog radio while the car's radio a fancy digital trunking system with encryption. The handheld only needs to reach their car, which handles the link between it and the main system. One thing though with such a simple system is the officer can't change frequencies on the car radio using the handheld. There are ways around this using more expensive handhelds and repeater systems, however.
 

IowaGuy1603

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Actually trunked systems normally don't need vehicle repeaters. The engineer normally makes sure there are enough towers in the service area that a HT can be copied by one of the towers the VAST MAJORITY of the time.

At one time CHP did use in car repeaters for their HT's Here is a link to a neat site that talks about them
CALIFORNIA HIGHWAY PATROL MOBILE RADIO EQUIPMENT 2001


The Iowa State Patrol uses HT extenders------------but most PD/SO in the state do not.
 

N0BDW

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Our Sheriff's department does not use mobile repeaters (regularly, anyway). They have mobile radios in their cars (generally CDM1250s I think). Not sure what they carry for HTs, but I wouldn't be surprised if they are still on HT1000s. Everything is VHF high analog. They have a repeater in a central location, much like you commonly find in amateur radio. I'm not sure if it is one or multiple sites, but everyone transmits on one frequency and the repeater picks that up and retransmits it on another frequency at higher power (and from a better positioned antenna). I've heard their system as far north as Lake Ontario (~40-50 miles). They definitely have coverage of the entire county plus I would guess pretty decent coverage of all of the surrounding counties.
 
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