BUILDING FAN DIPOLE OUT OF RG58 COAX ?

Discussion in 'Ham Radio Discussions' started by K5FRH, Jan 18, 2019.

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  1. K5FRH

    K5FRH Ham Member QRZ Page

    In looking around my shop to see what "surplus" wire I have in enough length to use for a fan dipole, I have several hundred feet of RG58 on a spool that I picked up at a garage sale for a very minimal cost. I am thinking about using it for an 80/40/20 fan dipole.

    I would like opinions as I may be overlooking something. For instance, if I short the center conductor to the shield on both ends of the coax and also where each piece terminates into the center feeder point, that should make each length of coax just one long wire....correct ? So not dealing with impedance or shielding issues.

    Also, what about building/winding my "ugly balun" also out of RG advice.58 instead or Rg8 as most articles demonstrate. I would still use RG8 as the feeder from transmitter to balun.

    I know I might pick up a little more wind resistance and weight than just using 14 gauge stranded wire,.

    Thanks for your opinions and advice.
     
  2. NL7W

    NL7W Premium Subscriber QRZ Page

    Too heavy.
     
    K7TRF likes this.
  3. NN4RH

    NN4RH Premium Subscriber QRZ Page

    Copper is copper, even if it's coax.

    But as you note it will be heavier than just wire.
     
  4. KE4OH

    KE4OH Ham Member QRZ Page

    Sounds like a good plan to me! It will be heavy, though. But so what? Back in the day, a lot of guys built double bazooka dipoles out of coax and they mostly stayed in the air.
     
  5. KP4SX

    KP4SX XML Subscriber QRZ Page

    IF its a good heavy copper braid then it should hold up ok. Now if its aluminum foil and a few strands the stretching will possibly break it.
     
  6. N2EY

    N2EY Premium Subscriber QRZ Page

    I wouldn't.

    The weight and wind loading are excessive. You'd be better off using "house wire".

    Electrically, it's fine. Mechanically.....not so much. In amateur radio, antenna design is mostly mechanical design.
     
    K7TRF likes this.
  7. WD8T

    WD8T Subscriber QRZ Page

    It several hundred ft of RG-58 is what you have then use it. As has been said it will be heavier and it may also be a bit of a headache to tune so I hope you have an analyzer to help. Do you plan on putting it up as a flat top or inverted V? Installing as an inverted V would be better in terms of supporting the center of the antenna because of the extra weigh of the coax..
     
  8. K4PIH

    K4PIH Ham Member QRZ Page

    I'd go to Home Despot and pick up a 500' role of THHN coper clad stranded insulated wire and build the fan out of that. Save the COAX for the feed run. The wire is around $50, lighter, cheaper, easier to handle than the 58.

    If you just have to get ride of the RG58 for free, my address is good.:)
     
    K7TRF likes this.
  9. KC8VWM

    KC8VWM Moderator Volunteer Moderator QRZ Page

    It's good for making buried radials for vertical antennas.

    Might be okay for making a single band antenna anywhere from 20-10m , but using it to construct a fan dipole is going to present some physical installation challenges.

    In terms of using feedline to construct Ugly Baluns, they are not effective over a wide range of frequencies. Typically these are only used on a single band antenna design and for everything else where choking common mode current is required over a wider range of HF frequencies, ferrite core material is your friend.
     
    Last edited: Jan 18, 2019
    K7TRF likes this.
  10. K5FRH

    K5FRH Ham Member QRZ Page

    thanks
     

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