Cb problems

Discussion in 'CB Radio Forum' started by Lillmann, Feb 16, 2013.

  1. Lillmann

    Lillmann Bobtail Member

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    Feb 16, 2013
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    Ok I have spent the last couple hours trying to figure out why when I hook up my cb to my truck (06 Mack granite series dump truck) when I run a single phase 50 ohm coax to either antenna I get perfect transmission I get a 1.5 swr, and no problems........BUT......when I hook up with cophase coax to both antenna my swr goes through the roof, and my antenna light comes on. I am using a cobra 29nw ltd classic as a radio, with a astatic 636l mic, and my antennas are k40 adjustables. What is the malfunction here???? Both the single coax, and the dual phase coax are brand new
     
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  3. kor b

    kor b Light Load Member

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    Dec 16, 2008
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    When you say through the roof, do you mean
    pegged, or 3.1 to 1? Your new cophase could
    be bad.
     
  4. Turbo-T

    Turbo-T Road Train Member

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    May 31, 2009
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    X2....on what's been said. Also I don't see the logic behind co-phasing. All it does is introduce problems.
     
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  5. n9mxq

    n9mxq Light Load Member

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    Aug 13, 2010
    Belvidere, IL
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    Is your cophase harness a 75ohm premade one, or is it a homemade harness? I'd disconnect the coax from everything, and check the coax for shorts. Check from the radio end to each end, and check the body of the connector to the center. If you have continuity between the center pin and the body of the connector you need a new cophase harness..

    I've cophased bunches of antennas and never had a problem. Once had cophased 102" whips on my car.. made drivethrus a pain, but talked all over...
     
  6. Lillmann

    Lillmann Bobtail Member

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    Feb 16, 2013
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    Yeah 3.1 and the coax is pre made I bought it yesterday
     
  7. MsJamie

    MsJamie Road Train Member

    Sounds like someone used the wrong type of coax on the harness...
     
  8. Voltrucker

    Voltrucker Medium Load Member

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    Sep 24, 2012
    West TN
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    First off, running 2 antennas is pointless. Does nothing except improve the look of your truck. Don't buy "premade" because its complete junk and poorly soldered. Go to a CB Shop and get them to solder it themselves. When buying mobile coax, MAKE SURE IT'S BELDON BRAND! The China made stuff is junk. Some people say the Beldon coax vs the China made stuff isn't different, well it is. Also, buy coax going by 3ft. For example: 3,6,9,12,15, so on. If you need 13 ft, buy 15 ft. This will keep your SWR down.
     
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  9. handlebar

    handlebar Heavy Load Member

    <ahem> Well, it's hard to argue with the facts as propounded by the previous poster, including the magic coax lengths....

    Cablewave has a factory 20 miles from me in North Carolina. Times Microwave (makers of the popular Amphenol line, as well as LMR-series cables) is based in Wallingford, CT.
    If you specify Beldon, you'll be out of luck; it's "Belden", and they have five regional facilities in the People's Republic of China. The ones in China are listed as sales offices... I suppose China *could* be importing stuff from here....
    I buy Cablewave's products mostly, because in some small way I like to think it's supporting my adopted home state, and I can get it with just a small mark-up for freight from distributors in NC & SC. I've even visited their factory for a sample of their radiating coax; nice folks.

    When I used to install cell site equipment and their microwave backhaul equipment, we usually used products from Times Microwave. It "swept" in our lab and held up as well in service as BeldEn, and cost us only about 60% what Belden did.

    But hey, if it weren't for personal opinions on gear, there would only be one manufacturer, and no reason for a discussion forum. Take a look at all the answers when someone asks, "Which brand CB should I buy?" It's your $$$.

    By the way, most hardline (Heliax® and other similar) connectors are assembled with nuts & bolts, spring clips, and *sometimes* a soldered center pin. Other tech departments prefer sliding center pins that allow for expansion & contraction with weather changes.

    If you can finagle a trip inside a mountaintop cell site sometime, take a look at the connectors on all the RG58-class jumpers. You'll probably see they're crimped, not soldered, and this is for stuff running around 2 GHz and above. Same thing for any public safety & paging gear in the site.

    We *could* solder everything, and risk distortion of the cables from heat (as should *anyone* who solders cable ends) but..... why bother? As long as you secure the lead from movement and waterproof the connector (as should *anyone* with *any* outdoor cables), AND you've got decent connectors AND crimp tool with the proper dies (around $300 for the last set I bought), you'll not find any difference in performance or reliability.

    I believe soldering is a reasonable choice for anyone who has only a couple of connectors to install. Even a half-dozen ruined silver/Teflon® connectors and an ounce of good solder don't approach the price of a journeyman-grade crimp tool set.

    Just one Olde Pharte's opinions,
    73
     
    Last edited: Feb 17, 2013
    EZ Money, MsJamie and n9mxq Thank this.
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