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Thread: Antenna Coaxial cable question

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    Antenna Coaxial cable question

    I have added 10' of aluminum mast pole to my antenna, it puts my cable run to radio in almost the exact length as specified. I have looped the cable around the pole 4 times and ty-wrapped so it doesnt swing in the wind ( sort of like the stripe on a barber pole). Receiving has not been affected but I feel my transmission is weaker. My SWR is 1.1, I show full modulation. Can this b affecting it? Coax against alum?

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    no...(about as simple and direct as I can get!)


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    BOOTY MONSTER (03-23-2016)

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    coax against metal , no . coaxial choke , possibly , but probably not .

    http://www.cbjunkies.com/threads/202...ght=coax+choke

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    I like the barber pole idea but when I put my masts up, the coax isn't taped down yet and goes straight up, no spin.

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    Quote Originally Posted by dice55 View Post
    I have added 10' of aluminum mast pole to my antenna, it puts my cable run to radio in almost the exact length as specified. I have looped the cable around the pole 4 times and ty-wrapped so it doesnt swing in the wind ( sort of like the stripe on a barber pole). Receiving has not been affected but I feel my transmission is weaker. My SWR is 1.1, I show full modulation. Can this b affecting it? Coax against alum?
    If you have excess try to make a 8" loop of around 3-8 wraps at the feed point. This will act as a RF choke. Coiling wire seems to make an inductor which you do not want. But what do I know, hope this helps.

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    to be a real RF choke the coax needs to be a specific length and diameter , and the type/velocity factor of the coax will have to be factored in ..... this post will explain it .

    http://www.cbjunkies.com/threads/202...ght=coax+choke

    'stripes on a barber's pole" would not cause any problems . think about it , the shield on the coax is ground , the metal mast is is most likely connected to the ground side/elements of the antenna so you mast is part of the antenna system and it's earth ground if it goes into the dirt all at the same potential . spiraling coax down around the mast won't cause problems , but you don't want to make a coax air choke around metal pipe or with anything that can react to RF inside of it , some plastics will . PVC pipe worked for me .

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    222FL (05-05-2016)

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    I'm curious as to the type of antenna?

    If an A99, Imax2000 or other radial-less types of antenna you could be tuning the mast with any RF leaking from the field in shield of the coax and making a(n out-of-phase) cancelling radiator beneath your antenna which could be destroying your pattern and lowering your performance.

    Do like Booty says & did and make a choke like his right at the base of the antenna, right below the feed point.

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    222DBFL (10-17-2016)

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    Coaxial length can be tuned or cut to specific wavelengths to get maximum power delivery at the antenna feed point. The top of the mast can be isolated from the antenna mount so that the ground provided to the antenna can also be manipulated to make it appear to be different heights above true ground. This can also be used as a point to attach guy wires, insulated from ground to act as radials.

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    222DBFL (10-17-2016)

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