Now For The Quad Of Mine
FOUR ELEMENT QUAD - FULLERTON RADIO CLUB
It is supposedly equal to a Cushcraft 11 element beam.
LR 21" per side LT 20.51" per side
84.1" total 82.04" total
Diagonal length 29.73" Diagonal length 29.01"
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LD - 1, 19.9" per side LD - 2, 19.7" per side
79.6" total 78.8" total
Diagonal length 28.14" Diagonal length 27.86"
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The antenna boom is made out of schedule 40 pvc pipe, 1" size, which is 1.5"
in diameter, actual size. The boom is approximately 42" long. The cross
pieces are 1/4 inch bicycle flag poles made out of fiberglass, or you could
use fiberglass fence posts available from Orchard Supply Hardware stores in
California.
TOP VIEW LOOKING DOWN
LR LT LD-1 LD-2
Vertical Polarization Feed Point
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V
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| <-----16.1"-------> | <----12.04"------> | <-----
0.2 wavelength 0.15 wavelength 0.15 wavelength
There it is folks and I hope that you are able to build it from these crude
instructions. REMEMBER FOR VERTICAL POLARIZATION, YOU FEED A QUAD FROM THE
HORIZONTAL SPREADER END. I think that one of the uses of packet should be the
desimination of information. This is my attempt at a construction article.
How about some more homebrew projects with illustrations on packet radio.
I would be interested in reports from anyone who builds this antenna.
Doug, KI6DS @ K6RAU-1
ANTENNA GAIN CHART
This is a chart to help you determine antenna gain based on
the number of elements.
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Antenna Type Decibel gain Decibel gain
over isotropic over half-wave
radiator dipole antenna
DBi DBd
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Isotropic radiator 0 -2.1
Ground plane +0.3 -1.8
Half wave dipole +2.1 0
5/8 wave +3.3 +1.2
quad loop element +4.1 +2.0
2 element yagi beam +7.1 +5.0
3 element yagi beam +10.0 +8.0
4 element yagi beam +12.1 +10.0
2 element quad beam +9.1 +7.0
3 element quad beam +12.1 +10.0
4 element quad beam +14.1 +12.0
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When an antenna is designed, the laws of physics have to be observed. Over
the years, some antenna manufacturers have inflated their gain figures to the
point that QST no longer allows gain figures to be published in antenna ads.
Hopefully, this chart will clear up some misconceptions about antenna gain.
NNNN
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