t-UHF

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mainetrunk

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Heres a good 1 for those who program public safety-or commercial radios. Why do we not use freq range 470.000---485.000? Mass is the only state near me that uses that rage. There are takers in N.H in Rockingham county, but most entities are in Mass. Why cant Maine use them as well.? Also, why cant the M.S.Comm project use them, if we dont? 1 more--the 500's, and 700's whats up with those? Can we use them?
 

mainetrunk

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Ahhh, well, never hurts to ask. Thanks.Time to study this stuff. It's getting funner.. Oh, 1 more.. How can a technician use a pl of say-210.7 on input, rx--192.8 pl...Who-how is the pl-or dcs programmer. I know a certain system where input is 192.8--rx is a dcs.. I know--study...
 

nd5y

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Most radios and programming software allow you to program separate transmit and receive tones the way you program separate transmit and receive frequencies.
 

mainetrunk

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What I meant is WHO decides the PL or DCS program? Is there a guideline as to what gets what? Example-say some town got their own dispatch-is there a designated P.L or do they do a coin toss. Is it the programmer that decides-or P.D? The reasopn I ask is I am used to Maine using 192.8-as Mass uses 131.8 and 146.2 constantly. Meanwhile in Me, certain towns have different P.L's..Like-Berwick Me. North Berwick has 127.3 P.L...WHO makes the call? Or is it a perfect tune issue? Thx AGAIN, stupid me
 

nd5y

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If a private two way radio shop sells and installs the radios for a government agency it is most likely that the agency supplies the radio dealer with all frequencies and tones to be programmed.

In some cases the frequency coordinators might coordinate what tones are used or there may be a regional planning commission or regional council of governments that does it. Ultimately it is up to the licensee to determine what tones to use. The FCC does not coordinate or license tones.
 

mainetrunk

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Well, thats a shocker. People just saying what their P.L will be..Someone decided that the Maine pl's for the most part is 192.8... N.H decided to be 136.5. Mass most used is 146.2 and 131.8.... O.K Same said for "nac"s ??
 

garys

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I think NH has more or less standardized on a NAC of 117.

As to coordination, it's pretty much ad hoc. Back in the mid 1970s when BAPERN and other regional systems were coming on line, the systems dictated what the PL would be. BAPERN was 131.8, NEMLEC 146.2, Plymouth County 203.5, and Bristol County 203.5. Frequencies were coordinated so that Bristol and Plymouth didn't overlap, so they could use the same PL on a few shared channels. NEMLEC used the same frequency range, but with a different PL.

One of the reasons for that was the technical limitations of the radios available back then. Nothing was computer based, it was all analog components. Adding multiple PL on a Micor radio meant adding a "Systems 90" component box. Adding scan meant another box, and so on. It was even tougher with portable radios. A MX portable could only have so many features or options added. That band width available was also why some agencies on UHF had to move to UHF-T, the radios just weren't that broad band.

Synthesized radios started to change that and now radios are wider banded, have way more options, can use any PL or DPL combination, etc. Individual components are needed, it's all done with firmware and programming.

Oh, as to the UHF-T band, public safety will have to move off of it in a few years. That spectrum is being refarmed so everyone on it will have to go somewhere else. That's one of the reasons that New York City got a waiver so they didn't have to narrowband their UHF-T.

Probably more than you wanted to know.

Well, thats a shocker. People just saying what their P.L will be..Someone decided that the Maine pl's for the most part is 192.8... N.H decided to be 136.5. Mass most used is 146.2 and 131.8.... O.K Same said for "nac"s ??
 

W1KNE

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Heres a good 1 for those who program public safety-or commercial radios. Why do we not use freq range 470.000---485.000? Mass is the only state near me that uses that rage. There are takers in N.H in Rockingham county, but most entities are in Mass. Why cant Maine use them as well.? Also, why cant the M.S.Comm project use them, if we dont? 1 more--the 500's, and 700's whats up with those? Can we use them?

Over at Scan New England, there is a WIKI page dedicated to T-Band use

T Band Allocations in the US - Scan New England Wiki
 

mainetrunk

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'Probably more than you wanted to know. ' No way. I am learning this stuff as I go along. Now-you take old movies-old police chases, Somkey and the bandit-Dirty Mary and crazy Lary.( which is hard to believe that helo out of fuel in a corn patch transmitted to everyone.weird) I study the old stuff to appreciate how far along we've come. In each movie radios are 1/2 the dialog. If you type in your aol nav--who designed the P.L system? The crazy answers. I'd rather hear too much,than not enough.Thx
 
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