[TowerTalk] 160-m Inverted L or Sloper?
jim at audiosystemsgroup.com
Mon Nov 14 16:34:47 EST 2005
On Mon, 14 Nov 2005 14:52:06 -0600, K4SAV wrote:
>I can only think of two possibilities that could cause this.
There is also antenna directivity, which can be quite significant,
even with relatively simple wires. For example, my 80/40 dipole at
home runs east/west, so is pretty dead going west. But if I run it
as a top loaded wire ( by tying both sides of the feedline together
and loading it against a counterpoise), it's at least a couple of S-
units better going west on 80 (both transmit and receive). That's
also a lot of dB. And I've observed this difference for azimuths as
different as AZ, LAX, WY, and WA.
Another example -- I have sloping dipoles hung off opposite sides of
a very big tower (150 ft tall, 35 ft square at the base, 25 ft
square at the top) at W6BX (see qrz for pix). Based on switching
between them on various signals, I would estimate their directivity
on the order of at least 6 dB front to back. Note these are NOT
slopers -- they have no electrical connection to the tower -- but
they certainly do interact with it. And I'm not "phasing" them --
I'm feeding one or the other at a time.
Jim Brown K9YC
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