View Single Post
  #5   Report Post  
Old January 28th 04, 05:09 PM
Richard Harrison
 
Posts: n/a
Default

Metalhead wrote:
"I am thinking about building a small receiving loop for 160 meters. I
can probably only get the loop about 50 feet or so away from my
transmitting antenna (inverted L)."

That`s only about 15 meters of separation and the wavelength is 160
meters. The loop is in the near field.

Suggestion: Change the L to a T. This balances out horizontal radiation.
Performance of the T is at least as good as the L, and the radiation
from a balanced T is cross-polarized with the horizontal loop. Symmetry
is important here. A horizontally polarized receiving antenna rejects
ground-wave propagated noise as there is no ground wave propagation of
horizontally polarized energy. The horizontally polarized loop is a good
choice for sky wave reflected signals as these are reflected from the
ionosphere with equal horizontal and vertical signal components,
regardless of the polarization of signal incident upon the ionosphere.

Just keep the horizontal portion of the L, and tap it at its center. Try
to keep the vertical portion as vertical as possible to maintain balance
between halves of the capacitive hat which now caps the vertical
antenna.

Best regards, Richard Harrison, KB5WZI