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  1. #1
    Experienced
    Join Date
    Oct 2006
    Location
    Dubuque, IA
    Posts
    247

    Default Mobile 800 MHz Scanner

    Ok, I'm going to start this post off by saying that I currently know practically NOTHING about trunked scanners. I live at the northwestern point of Illinois, so I have Iowa and Wisconsin radio traffic that pertains to areas near me. I'm nosey, so I naturally want to listen to LEO activity around me. Picking up my Illinois and Wisconsin frequencies is no problem with my Uniden Bearcat BC145XL 16 channel base scanner. However, the Iowa frequencies near me I cannot pick up. All that I know about them is that they are trunked and in the 800 MHz range. A friend of mine highly recommended the Radioshack Pro-94 scanner. This is a dual-trunking scanner. Could someone explain to me what "dual trunking" and "triple trunking" really are? I see that there are several different 800.xxx MHz frequencies for the same city. How does this all work together? What is a talkgroup? I have read all over the place but I can't find one simple explanation on what is going on. Any help would be appreciated.

  2. #2
    Experienced
    Join Date
    Dec 2005
    Location
    SoCal
    Posts
    211

    Default

    I hope I can give you good info. I've only been into scanning for less than a year so I'm still learning.

    Conventional radio requires 1 dedicated frequency per group of people communicating. It's considered very inefficient for an area that has several agencies that need to use the radio system. A trunked system can support several groups of people (talkgroups) while using fewer frequencies. This is because a trunked system uses a "control" frequency (it sounds like a computer modem if you tune to it) and a few voice frequencies. A trunked radio or scanner will receive data from the control frequency that tells it what available voice frequency to tune to in order to hear the voice traffic.

    Some of the most common trunking systems are Motorola, EDACS, and LTR. Dual trunking means the scanner supports 2 of those trunking systems. Triple trunking means it can scan 3 of those trunking systems. You will need to find out what kind of trunking system your area uses so you can buy a scanner that supports it. If your area only uses a Motorola system, then getting a dual or triple trunking scanner may be a waste of money since you'll never scan the other trunking systems the scanner supports.

    With a scanner, you would setup 1 scan bank as a trunked system. It will ask you what kind of trunked system it is, the control frequency, and some other parameters. All of which are usually available on the internet. Then you would program all of those 800mhz frequencies into your scan list for that bank. Your scanner would then monitor the control frequency for data. Once it receives information of an incoming transmission, it will tune to one of the several 800mhz frequencies you programmed into your scan list for that bank.

  3. #3
    Advanced Member
    Join Date
    Feb 2005
    Location
    Southern MA
    Posts
    10,127

    Default

    I use a BC246t for analog 800MHz trunked system and it does great. I have upgraded the reception with a Radio Shack 800mhz antenna

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  4. #4
    Street Lawyer
    Join Date
    Jul 2006
    Location
    719, Colorado
    Posts
    7,108

    Default

    Gotta love the bearcats, but I'm happy w/ the pro-97 tripple-trunk tracking for analog.. gotta admit I wish I had digital tho

  5. #5
    Professional
    Join Date
    Sep 2006
    Location
    NC
    Posts
    1,242

    Default

    Quote Originally Posted by Lucky225
    Gotta love the bearcats, but I'm happy w/ the pro-97 tripple-trunk tracking for analog.. gotta admit I wish I had digital tho
    Yeah too bad the Digital scanners are $450+ unless you're lucky to find a cheap one on ebay :cry: the statewide here is starting to be put on a digital system.

  6. #6
    Experienced
    Join Date
    Oct 2006
    Location
    Dubuque, IA
    Posts
    247

    Default

    Thank you for the good explanation, Mase. Ok I have looked up the the trunked system on RadioReference and found the following frequencies:
    Dubuque1, IA 01 857.46250 02 858.46250 03 859.46250 04 860.46250 05 858.71250 06 859.71250 07 860.71250
    Dubuque2, IA 01 861.48750 02 862.48750 03 863.48750 04 864.48750 05 865.48750
    Dubuque3, IA 01 861.83750 02 862.83750 03 863.83750 04 864.83750 05 865.83750 06 861.76250 07 862.76250 08 863.76250 09 864.76250
    Those are the frequencies for the city that I want to listen to. Now on RadioReference I see that control channels are the ones in red, however none of these are listed in red. Also, why would there be 3 different Dubuque, IA sections listed? So, would the Pro-94 be a good buy for me and would it also pick up my conventional 154-160 MHz traffic?

  7. #7
    Professional
    Join Date
    Sep 2006
    Location
    NC
    Posts
    1,242

    Default

    That looks to be an EDACS system. A little different from a Motorola system. In an EDACS system you have to put them in a bank starting at X1 (1, 51, 101) and put them in the order listed on the site.


    Yes the Pro-94 would work just fine and the Pro-94 also covers the conventional channels. I have the state wide 800Mhz trunked system and the local conventionals in mine and it works like a charm.

    You can read up some more on the Pro-94 on their wiki page: http://wiki.radioreference.com/index.php/Pro-94

    which tells which ranges it covers:
    Frequency Coverage: 29-54, 108-136.975, 137-174, 216-224.995, 406-512, 806-823.9375, 851-868.9875, 896.1125-956 (excluding cellular) and 1240-1300 MHz

  8. #8
    Experienced
    Join Date
    Oct 2006
    Location
    Dubuque, IA
    Posts
    247

    Default

    Ok so if there is no control channel, how does the scanner know where to go for further broadcasts? This is all so foreign to me. Haha. I appreciate your help, cooljay and Mase. Also the Illinois State Police use Starcom21, an Illinois statewide trunked radio system. I believe it is a Motorala system. On RadioReference it's listed as both "Project 25 Standard" and "Statewide Digital APCO 25 Trunked Radio System." I'm not sure what this means but I remember reading somewhere that it was Motorola-maintained. The Pro-94 is not digital, is it? I'm assuming a scanner for the digital trunked system would cost a significant amount of money? Thanks for the information, people!

  9. #9
    Professional
    Join Date
    Sep 2006
    Location
    NC
    Posts
    1,242

    Default

    P25 and APCO25 are 99% of the time digital although you do find some mixed analog/digital. Yes the digital scanners do cost more ($450-$500) and the Pro-94 is analog only. As far as the control channel goes which system are you trying to look up exactly? I'll take a look at it and see. You can PM me the info if you'd like. Since posting the link from RR won't work cause it's a dynamic page but the url stays the same.

  10. #10
    Experienced
    Join Date
    Oct 2006
    Location
    Dubuque, IA
    Posts
    247

    Default

    Cooljay, I really appreciate your help on this. So listening to anything useful from the Illinois State Police and their digital system is pretty much a no go for me if I'm unwilling to spend more than $150. Haha that's one question down. The area I'm trying to look up: go into the RR Database and click Iowa, then click Dubuque county, it'll list a few police frequencies in the 400 MHz range that are backup frequencies only. Under "All trunked radio systems in Dubuque county," you'll see "RACOM". In there you'll see the 3 Dubuque, IA frequency lists that I posted above, close to the top. I still haven't got a full understanding on why there are 3 sets for one city? FYI Dubuque is the name of the city and the county, lol. I am assuming they are listed that way for a reason and that they go together a certain way? Perhaps you could shed some light. Thanks again in advance.

 

 

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