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High Gain VHF/UHF Collinear J
Pole A collinear (or co-linear) antenna array is an array of dipole antennas mounted in such a manner that the corresponding elements of each antenna are parallel and collinear, that is they are located along a common line or axis. A collinear array is usually
mounted vertically, in order to increase overall gain and directivity in
the horizontal direction. Theoretically, when stacking idealised lossless
dipole antennas in such a fashion, doubling their number will, with proper
phasing, produce double the gain, with an increase of 3.01 dB. In
practice, the gain realised will be below this due to losses.
(From Wikipedia) Antenna pattern is OMNI Directional Lengths and dBd gain 2 meters length and dBd gain 440 band length 3 element = 12 feet long 7.2 DBD's gain 5 ft. 5 element = 19 feet long 9.7 DBD's gain 8 ft. 10 element =
36 feet long 13.0 DBD's
gain 14
ft. More than 15 elements not recommended as the radiation pattern gets too tight for normal use.
Gain on a 15 element is 14.45 dBd Could be built as a dual band but I, myself do not recommend it as a dual band design. This antenna
design does NOT use radials, it uses the J POLE bottom feed system, so it
will match any feed line. Antenna gets very long (tall) when more than 5
elements on 2 meters but much shorter on the 440 band!
Note
that the antenna is one continious length from top to bottom WB3AYW xls document download with working calculator Many thanks to WB3AYW and KK1CW for providing this project! Any questions about this antenna must be emailed to: wb3ayw AT tds.net See the WB3AYW web site for more antennas.
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