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Thread: LTR

  1. #1
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    Default LTR

    I have to ask a question, is LTR different than the LTR Passport system that Nat Grid uses? and if so, can you help me to understand the difference or why is Nat Grid not available to monitor except when their LTR frequencies are put in a conventional system?
    Thanks
    John
    BC IV, BC H/L, BC210, BC100, BC350A, BC100XLT, 996XT, 396t, 436, HP1

  2. #2
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    I moved this to the Area Trunked Radio forum.

    Radio Reference has a good description of the various types of LTR. There are hybrid systems that have both Passport and regular Talk Groups. I think the problem is that scanners won't track the TGs on a Passport system.
    We're peace loving people, we're not hunting trouble, but if trouble should find us, we'll stand up and fight.

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    I tried to ask this question yesterday but it did not get submitted to the forum, so here goes again...
    Can someone explain the difference between this and the Nat Grid LTR passport system and why one can be heard and the other not unless you program the frequencies as a conventional system?
    Thanks
    John
    BC IV, BC H/L, BC210, BC100, BC350A, BC100XLT, 996XT, 396t, 436, HP1

  4. #4
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    IT did get posted. I just merged your 2nd post into the original thread
    Quote Originally Posted by IggyWFD View Post
    I tried to ask this question yesterday but it did not get submitted to the forum, so here goes again...
    Can someone explain the difference between this and the Nat Grid LTR passport system and why one can be heard and the other not unless you program the frequencies as a conventional system?
    Thanks
    Bill Dunn N1KUG
    Cruise Ship Frequencies
    http://scanmaritime.com

    "The tougher it is to find a frequency, the more it makes me want to work to find it. - I've learned to use the SEARCH Button"

  5. #5
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    Hello,

    Regular LTR is the older and very basic trunking system for businesses. It is supported by the various scanners. Companies have added to the over-the-air protocol to support additional features. One such system is LTR-Net that used to be popular down in RI. LTR-Net systems can be decoded by scanners. Other companies changed the over-the-air protocol to add features, such as Passport and Muti-Net. Because the data transmitted is different, Passport can not be decoded by a Regular LTR decoder.

    73 Eric

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    Quote Originally Posted by IggyWFD View Post
    I tried to ask this question yesterday but it did not get submitted to the forum, so here goes again...
    Can someone explain the difference between this and the Nat Grid LTR passport system and why one can be heard and the other not unless you program the frequencies as a conventional system?
    Thanks
    I'm not familiar with the National Grid system itself. But basically, Passport is a proprietary extension on top of LTR. As as I understand it, the developers of Passport have refused to license the technology to scanner makers.
    Matt
    Lowell, MA

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    Thanks Bill, I didnt see on my end until the merge
    John
    BC IV, BC H/L, BC210, BC100, BC350A, BC100XLT, 996XT, 396t, 436, HP1

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    Thanks all, you helped me to get a better understanding
    John
    BC IV, BC H/L, BC210, BC100, BC350A, BC100XLT, 996XT, 396t, 436, HP1

  9. #9
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    Hello,

    Now that I have better receivers with spectrum displays, I should look at the National Grid Passport system again. It is mostly on auctioned frequencies on 454 MHz with a 6.25 KHz frequency step. I figured out some sites years ago, but there were some sites not quite online at the time.

    There is only one program that can decode Passport, but it runs under DOS. I do not even know if Windows 10 can still run DOS programs anymore.

    So many frequencies, so little time...

    73 Eric

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    SDRTrunk will trunktrack Passport systems, I run it on the Marcus sites in CT.

    chris

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    Huh, a thought just occurred to me... Would a Passport-capable radio work as a receiver on Passport systems, or is there mandatory affiliation / a system key? I've got a couple HT1250s that I think support Passport. Curious if they could safely be used RX-only, or if it's like programming up a SmartZone radio (i.e., a baaaad idea).
    Matt
    Lowell, MA

  12. #12
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    The radio ID (ESN) needs to be registered on the system in order to trunktrack it.

    chris

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