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I
can't speak to 220 Mhz but can provide info on the history of our club 2 meter
repeater at 1200 ft on a triangle TV station tower.
single
DB224 on one leg about 2-3' out. mounted straight out form the point of
the leg. Worked great 60-70 miles out where you could see the
antenna but on the opposite side in the shadow of the tower maybe 20 miles range
at best. Not a significant different between omni arrangment in line mounting of
dipoles pointed away from the tower.
Three
DB224 one on each tower leg dipoles in line pointed away from the
legs antennas close mounted about 4" off the tower leg. You could hear the
repeater well in certain areas on all sides of the tower but lots of nulls in
the pattern. One of which went right across the major population
center. antennas fed in phase with a 3X divider. Bad news
setup.
DB228
close mounted on one leg of the tower about 2" dipoles in line punted straight
out from the point of the triangle. Faces the major population area.
DB224 close mounted on one of the other tower legs dipoles in
line perpendicular to the tower face and pointed
opposite the DB228. Both
antennas fed in phase with a 2X power divider. 70 mile radius coverage for
mobiles no nulls found in pattern. Everyone is happy with the
performance.
As a
side note to another thread it takes 250- 300W Tx power to balance the repeater
Rx coverage for mobiles stations.
Another repeater in the area had a DB224 mounted about 2' off the
side of a smaller tower about 400 ft up with the dipoles arranged omni with
reasonable coverage. They went out to about 4' off the side and
pointed the dipoles in towards the tower inline. Performance dropped
drasticaly, didn't take long for them to go back to the other
arrangement.
John Lock KF0M
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- RE: [Repeater-Builder] dB224 4 bay 220 MHz Antenna on VERY LAR... kf0m
