Hey antenna experts

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by W4HWD, Dec 22, 2007.

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  1. KA0GKT

    KA0GKT Ham Member QRZ Page

    In the words of a very wise man (My Father...Please don't tell him I said that... [​IMG] ) If efficiency and VSWR were synonymous, the Heathkit Cantenna would be the DXers choice for an antenna.

    73 DE KAØGKT/7

    --Steve
     
  2. KB9WIS

    KB9WIS Ham Member QRZ Page

    IMAX 2000 upgrade

    For the price, the IMAX 2000 isn't a bad CB antenna, that can cheaply be converted to the ham bands. You could also scrap the insides of these, and make them better, and even convert them for many more bands by redoing the coil inside. If you do a google search for IMAX 2000, you'll actually come across a website of a guy that converts and upgrades these CB antennas.

    The IMAX 2000 comparison page is http://www.bighairantennas.com/BigHairsAntennasversuscompetitors.html

    And I believe there is more cb antennas info at http://www.bighairantennas.com/CB_Antennas.html
     
  3. W8JI

    W8JI Ham Member QRZ Page

    Without the radials, the entire feedline is part of the antenna.

    A great big long lossy antenna always has wider bandwidth than a shorter and more efficient antenna has.

    What you really did is stop the feedline from being so much a part of the radiating system, and the feedline is acting more like a feedline and less like a longwire antenna. More of the radiation comes from the antenna now.

    73 Tom
     
  4. W8ATA

    W8ATA Ham Member QRZ Page

    Yep, some times we do the right thing and don't realize it as you did in adding your radials like W8JI says.

    But I have another comment which is not in any way meant to be mean-spirited. To expect W8JI or any of the multitude of talented hams with websites to answer our emails is not realistic nor is it fair to say they don't care. This is especially true if they (present company included) do design work for some of the equipment manufactures. We would deluge them with emails instead of contacting customer service. These forums are a great service to ham radio, and we take pot-luck who responds to our questions.

    But please guys don't let my comments change the focus of this thread.
    W4HWD did ask a good question.

    73,
    W8ATA
     
  5. G0GQK

    G0GQK Ham Member QRZ Page

    The antenna is working properly now that it has radials, this is called a ground plane antenna and it seems to me that it is intended for the CB frequencies. There is no way a decent, well designed, efficient vertical antenna will be working as it should around 28.500 Mhz, and be anywhere near resonance at 24.950, 21.200 or even in the same ballpark as 18.109 !
    If you use an ATU it will bring the system into 50 ohms to match the rig but the radiation pattern will be extremely poor. Has everybody explained things so that you now have a better understanding ?

    G0GQK
     
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