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Old June 17th 04, 09:10 PM
iamnotjebbush
 
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In , wrote:


I just tested my 9' whip (mounted on the roo-guard of my Dodge). Tied
it back so the top was parallel with the ground (pointing East, if
that makes a difference). Measurements were compared to the antenna
straight up.......;

SWR didn't change at all, and vertically polarized field strength
dropped by a hair. However, horizontally polarized field strength made
a huge jump to the good. Subjectively, I listened to the toilet bowl
while pulling on the lanyard. Some weak signals disappeared while
others came in that weren't there before. Let the whip go back to
vertical and the old signals came back while the new signals were
lost.


Let's see..............An antennas bent so that the tip is parallel to
the ground?.............That represents an antenna that is now midway
between horizontal and vertical polarization.



Wrong. That represents an antenna with -both- horizontal and vertical
polarization.


The theoretical gain of that antenna should be equal between
polarizations. When such a scenario is in place the field strength
should drop to .707 of it's original. That represents a 3db loss
just from this antenna being bent.



Wrong. The theoretical gain of the antenna for a given polarity is a
function equal to the sum of the gains of equally spaced tangents
along the curve of the antenna.


Yet you stated....................................

"vertically polarized field strength dropped by a hair."



As measured by my FSM.


When testing mobile antennas a 3db loss is huge.
Most all well designed efficient non bent antennas
will easily beat your -3db antenna.



I did not say that it dropped by 3dB. The phrase "by a hair" is not my
words but the words of my spotter, and both of us generally use that
phrase to describe a meter shift approximately equal to the width of
the needle. And since the FSM used was only a 'relative' FSM (as
opposed to a CISPR quasi-peak detector), there is no way to quantify
"by a hair", nor did I attempt to do so.







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