Topband: Close to earth Beverage.

[john battin]

  ----- Original Message ----- 
  From: Tom Rauch<mailto:w8ji at contesting.com> 
  To: john battin<mailto:jbattin at msn.com> ; k1fz<mailto:K1FZ at prexar.com> ; topband at contesting.com<mailto:topband at contesting.com> 
  Sent: Friday, November 19, 2004 7:24 AM
  Subject: Re: Topband: Close to earth Beverage.


    All this may be fine but with beverages 8 foot beverages,
  on higher frequencies if I cut the beverage off  and just
  leave the feed, the signal stays the same. As the frequency
  goes lower the effect diminishes but still is enough to
  effect f/b and f/s. I  have measured it.<<>>

  I wasn't clear. I was talking about 160 John.

  On ten meters it makes a big difference because radiation
  resistance is a large part of the overall system impedance.

  As I recall you measured end radiation using a "T" or
  center-tapped 1/2 wl wire for termination.

  When a 1/2 wl wire (with center used for ground) is placed
  over lossy soil it actually receives quite well. If you look
  at an eight foot high "T" antenna over lossy soil the
  radiation of the horizontal wire dominates the pattern, even
  in a model with perfectly homogeneous soil and perfect
  balance!

  The "non-radiating" termination "T" is anything but
  non-radiating, and the field it radiates and responds to is
  (no surprise) vertical. Short of installing 50 or 100
  radials eight feet high, I can't think of any way to measure
  vertical end-effect on 160.

  I think some Beverage books and other sources have blown the
  vertical end effect all out of proportion for bands where
  the antenna is 1/50th to 1/100th of a wavelength above
  ground. It started a few rumors or myths that just aren't
  true.

  73 Tom


  This may all be true, but my measurements show that the signals off the back and sides of  my beverages are dominated by pick-up in the feed wire. If I am listening to signal off the side, and cut the beverage off and just leave the feed, the signal stays about the same. There is little  that can be done about it, except as was suggested at the start of this thread ,,,, lower the beverage and trade off end effect for beverage performance.

  John 
  K9DX