On Feb 11, 2005, at 12:13 AM, Vic Rosenthal wrote:
I am experimenting with using the K2 rant input (that's receiver
antenna, not verbal outburst).
I want to use my 20-meter quad as a receiving antenna when I am
transmitting on 160 with an inverted L. It is a lot quieter. The L
is right next to the quad, so a lot of voltage is induced in the quad
when transmitting with high power.
Vic,
I think you may be missing the point of using a separate receiving
antenna on noisy bands like 160m.
While the 20m quad may be quieter, that's likely due to the smaller
size and gross impedance mis-match of the 20m antenna on 160m. The 20m
quad is probably quieter for ALL signals and noise alike, which doesn't
help.
The key to using a separate receiving antenna on 160m is NOT just to
have a quiet, lossy antenna -- but to have a quiet, lossy, DIRECTIONAL
antenna. The idea is to improve the signal / noise ratio by limiting
the noise intercepted at the antenna. Since noise is generally thought
to come from all directions, using an directional antenna makes signals
appear stronger.
The Beverage antenna is probably the most popular receiving antenna in
this service, but requires a lot of real estate. For 160m, a Beverage
would be about 500 feet long.
For those of us without room for such an antenna, the flag, pennant and
K9AY loop are good substitutes. These antennas have a cardioid
(heart-shaped) pattern, with a strong null in the opposite direction.
Magnetic receiving loops area also useful, particularly for nulling out
strong local noise sources.
All of these receiving antennas should be mounted well away from the
transmitting antenna, to avoid the type of coupling you're having
trouble with now, as well as to avoid noise reception due to mutual
coupling. Since these antennas are intentionally lossy, it usually
doesn't take that much distance to avoid transmitter overload.
Bill Coleman, AA4LR, PP-ASEL Mail: [EMAIL PROTECTED]
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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