[Antennas] W3EDP and mobile antennas

2002年5月19日 21:59:06 +0200

Joe
If you connect your radio to a dummy load and hit the tune button, it will
also show that the "antenna" is tuned. Of course no signal will go out or
come in, because the dummy load has zero efficiency as an antenna.
Operators have tuned window frames and bedsprings and worked DX, but they
probably would have had better results with a simple dipole.
An antenna must be properly tuned and have the right radiation
characteristics to be an efficient antenna.
Your incomplete mobile antenna does not have the correct radiation
characteristics without its whip and the tuner only presented the radio with
the correct impedance. The RF was dissipated as heat in the coils and the
rest of the antenna system, instead of being radiated as a decent signal.
Deon ZR1DQ
.
----- Original Message -----
From: Joe Falcone <[email protected]>
To: <[email protected]>
Sent: Sunday, May 19, 2002 12:41 AM
Subject: [Antennas] W3EDP and mobile antennas
Regarding "gain": You do get gain in one or more directions but you would
then lose in one or more directions. I realized with the "long wire" I
could get gain in the direction that I was stringing the wire if I went long
enough, (and losing it in other directions), but that was not the purpose of
why I wanted a W3EDP antenna. I just wanted one that radiated more or less
in all directions.
I imagine that there is a point where your antenna, if it is too short, will
not be able to radiate all its energy, even if you use a tuner, and then you
will experience a loss of power going out and a loss of signal coming in.
I once talked to the owner of the Lakeside antenna company. The one that
makes those Hamstick antennas. I had hamsticks on my car and had a Yaesu
radio with a built in tuner. I could tune the antenna with just hitting the
button on the radio even without having the stainless steel whip on the
antenna. The whip was one-half of the physical length of the antenna. I
called the owner and asked him if the antenna would work just as well
without the whip as long as I could get a match on my tuner. He said no,
that it needed the whip. (He was very nice and said that everyone wanted a
short mobile antenna and if he could make one that worked as well being
short without the whip, he would.)
I still did not understand that if I could tune it why it was not working as
well as if I had the whip on it. Could someone answer that? Thanks, Joe.
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