Author Topic: Trunk repeater?  (Read 7095 times)

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jsr5

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Trunk repeater?
« on: October 28, 2012, 12:08:13 AM »
Back when I was a cop the troopers (I wasn't a trooper) had a item called a trunk repeater in their cars that allowed them to be away from their cars on a HT but still contact bases and dispatches at a better power level than the HT's limited 5 watts. Anyone have any familiarity with those anysuggestions on good ones. Are there any that have a frequency range similar to the baofeng 5rb ht's would they be better than having a stand alone Mobile unit? just not sure what they can do. is it just a fixed one freq in one freq out sor t of thing or can you program them to work more than one freq in and maybe even more than one out. Any that would work with stuff in the FRS or GMRS range as I have some of those worked into my close in communications system because of cost and they were what I started my system with way back when. Part of the reson I decided to go with dual band HT's as my next step up is because those can be networked with the FRS/GMRS loved that bit of flexibility and that it added to my current stuff rather than started over from scratch. NOt to mention if things are bad long term there are alot of those lil frs/gmrs units out there that can be talked to or received from.

TIA

BTPost

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Re: Trunk repeater?
« Reply #1 on: October 28, 2012, 01:44:43 AM »
A couple of things that need to be considered. Usually these type units are designed for VHF to base stations, and UHF to the portables.... Crossband operations, all licensed under one System License under Part 90. Hams can do the same thing using their Repeater Subbands. FRS does NOT ALLOW repeater usage. GMRS however does allow Repeaters, but requires specific System Licensing. You can NOT mix Ham operations, with any other Radio Services, in the USA. Motorola made the best setups for Mobile Repeaters. They were very expensive, and we're setup on a very limited number of frequencies for each band. Usually 1 or 2 on the VHF side, and a single Pair on the UHF side. Usually they were Manual Channel selection, that depended on the area of Operation, with a fixed pair to the portables. Problems occurred when more than one mobile Repeater was operating in any one location. Things got messy with multiple VHF transmitters repeating back to a Base, triggered by the same portable.  Some used specific PL Codes on the UHF side to alleviate this issue, but that meant that the Portables had to be assigned with the vehicle, and NOT the user.
There are a few Crossband Dual Band Ham Radios that can do this, if properly configured.
Bruce in alaska AL7AQ

jsr5

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Re: Trunk repeater?
« Reply #2 on: October 28, 2012, 07:13:12 PM »
MOst of the troopers took their cars home so I suppose that is one more of the reasons for them to do so. Seems like somthing to leave until much farther down my road in geting set up then. And not quite as efficient as I thought they might be. As for FRS Gmrs legalities suppose I could still have stuff buried back on the shelf for if and maybe but doen'st sound cost eficient to do so. Adn I would have to come along ways in my learning to even be able to set somthing like that up since it's obvious that if it's not legal it's not for sale either. 

ohgary

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Re: Trunk repeater?
« Reply #3 on: December 29, 2012, 09:11:51 AM »
most of those trunk repeaters were not repeaters but cross band range extenders.

Tempstar

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Re: Trunk repeater?
« Reply #4 on: December 30, 2012, 05:46:10 AM »
You're talking about a mobile extender. Motorola had the PAC-RT (pack rat) that extended the HT range, and GE had the MVP radios with that feature. They were in-band repeaters in the car. Trunking is a different system where the radios are frequency agile and controlled by a computer, and can switch channels (without user input) to the best reception and least busy available frequency. If you want GMRS/FRS frequencies, grab a pair of Maxtrac UHF mobiles from Ebay along with  a repeater cable and you'll be in business with a repeater.
 You can't legally use these on FRS, but you can do up to 40 watts on GMRS and have repeaters. Mygmrs.com has listings of these repeaters all over the US. With an $85 (for 5 years) license you can use this system legally. These bands are also exempt from the narrow banding that has to be complete by Jan 1 2013, so right now the equipment is cheap because the market is flooded with radios incapable of the narrow band.
« Last Edit: December 30, 2012, 05:52:22 AM by Tempstar »
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