1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice

Collinear

Discussion in 'CB Antennas' started by Hotrod2020alabama, Aug 16, 2018.

  1. Hotrod2020alabama

    Hotrod2020alabama New Member

    Joined:
    Mar 18, 2018
    Messages:
    1
    Likes Received:
    0
    Collinear antenna for cb band. I have thought about getting 2 spt 500 and put one up and then one down without the ground plane but how would I connect the two? 75 ohm coax cable or 50 ohm coax? Anyone got a way I could do this and it work?


     
  2. Shockwave

    Shockwave Sr. Member

    Joined:
    Sep 19, 2009
    Messages:
    2,592
    Likes Received:
    820
    Since a 5/8 wave antenna can be matched at 50 ohms with just an inductor placed in series at the feed point (no tap to ground), why not consider replacing the ground plane radials with another 5/8 wave radiator and matching inductor below the first? Then it's a balanced antenna where both coils can be fed with the coax through a ferite balun.

    People have been doing this for years with high impedance ladder line feeding the two 5/8 wave antenna sections but I think a pair of inductor coils at the feed point could directly match this collinear antenna to 50 ohm coax with just a balun added. Two Sirio Tornado 5/8 wave antennas without the radials would lend themselves well to this modification since their matching coils are not DC grounded.
     
    #2 Shockwave, Nov 8, 2018
    Last edited: Nov 8, 2018
    Shadetree Mechanic likes this.

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!