[TowerTalk] 80m antenna

[L. B. Cebik]

John,

I cannot speak to the interaction question on your proposed 80-meter
dipole, although the spacing does seem close.  However, a rotatable dipole
has distinct advantages over an inverted Vee.

Let us assume that the two have a common top level.  The dipole maintains
this level, while the Vee legs slope, reducing the height for much of the
higher current and stronger field levels from the antenna.  The dipole
pattern will have more gain and higher front-to-side rejection than the
Vee.  If the dipole were in a fixed position, this might be a problem, but
since it is rotatable, this turns into an advantage, since max gain goes
toward the desired station and side QRM is reduced in strength.

For amateur radio work, a rotatable dipole is almost universally (but
short of absolutely) an advantage over a fixed dipole or Vee antenna at
the same top height.  The side rejection alone increases signal to noise
ratio.  If a dipole is shortened and loses just a bit of gain, it retains
the front-to-side rejection that is so helpful under noisy conditions.

Good luck with the project.

-73-

LB, W4RNL

L. B. Cebik, W4RNL         /\  /\     *   /  /    /    (Off)(423) 974-7215
1434 High Mesa Drive      /  \/  \/\     ----/\---     (Hm) (423) 938-6335
Knoxville, Tennessee     /\   \   \ \   /  / || /      (FAX)(423) 974-3509
37938-4443     USA      /  \   \   \ \       ||              cebik@utk.edu
                URL:  http://web.utk.edu/~cebik/radio.html




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