Callsign
ad: IACantenna-1
Results 1 to 3 of 3

Thread: vertical antenna problem

ad: L-HROutlet
ad: l-assoc
ad: l-Waters
ad: l-WarrenG
ad: l-Heil
ad: l-tentec
ad: l-rl
ad: l-gcopper
ad: l-innov

Contribute
to QRZ

  1. #1

    Default vertical antenna problem

    I have a A-99 for 10 meters, works well. I went to 80m with it, ( just recieve, no TX) done great utill I started to thread the pl 259, soon as the barrel touched the rigs so- 239, recive went to 25% of what it was with just the center of the pl 259. what caused this?? thanks don. ke4qco

  2. #2

    Default

    The antenna is effectively a short circuit on 80m, by design.

    When using only the center pin of the coax, you're using all of the coax plus all of the antenna as a long wire antenna. As soon as you connect the outer conductor (connector shell), that "feature" goes away and the antenna is essentially a short circuit on the end of the coax.

    It was never designed to be used on 80m. Actually it was never designed to be used anywhere except 25-30 MHz.
    What if soy milk is just regular milk introducing itself in Spanish?

  3. #3

    Post

    Wavelength of the Radio Waves matter !!

    3.5 - 4.0 MHz or 80 meters .... the wavelength is EIGHT times (Longer) that of 28.0 - 30.0 MHz or 10 meters.
    The Audio analogy is :
    Trying to have a Soprano voice (A99, for 11/10 meter) sing the Bass musical line (80 meters) :-).
    ===
    Don -

    Best 80 meter antenna (covers full 500 kHz) is 1/2 dipole with parallel elements 2-3 feet apart (fat dipole) .... that antenna is ~ 135 feet in length (a real estate problem for many).

    N3UJJ Antenna Project
    http://n3ujj.com/the_N3UJJ_antenna_project.html

    Shortened antennas for 80 meters (Verticals or Horizontal Dipoles) suffer from narrow bandwidths.
    Last edited by W9GB; 05-02-2012 at 07:25 PM.
    Nullius in verba

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •