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## Re: [TowerTalk] Trapped Tribanders Turned Vertical

 To: towertalk@contesting.com Re: [TowerTalk] Trapped Tribanders Turned Vertical K4SAV Wed, 20 Jun 2007 10:01:27 -0500
 ```K4SAV wrote: The higher the antennas are, the less difference in gain there will be between mounting vertically and horizontally. W4TV wrote: Not true ... the vertical beam will always miss the "ground gain" and will lag the horizontal antenna by three to six dB. ------------------------ Well, my original statement is not 100% true for all heights, and neither is yours. Here are some EZNEC numbers for a three element Yagi turned either vertically of horizontally. Height ___ Horz Antenna ______ Vert Antenna ____ Gain Difference 20 ______ 9.6 dBi at 36 deg ___ 4.8 at 17 deg ______ 4.8 dB 30_______11 dBi at 28 deg _____ 5.7 dBi at 15 deg __ 5.3 dB 35 _____ 11.6 dBi at 25 deg ____5.9 dBi at 13 deg __ 5.7 dB 40 _____ 11.9 dBi at 23 deg ___ 6 dBi at 12 deg ____ 5.9 dB 80 _____ 12.7 dBi at 12 deg ___ 8 dBi at 9 deg _____ 4.7 dB 100 ____ 12.9 dBi at 10 deg ___ 8.8 dBi at 8 deg ___ 4.1 dB 120 ____ 12.9 dBi at 8 deg ____ 9.4 at 7 deg _______ 3.5 dB 150 ____ 13 dBi at 7 deg ______ 10.1 dBi at 6 deg __ 2.9 dB 200 ____ 13.2 dBi at 5 deg ____ 10.8 dBi at 5 deg __ 2.4 dB 300 ____ 13.1 dBi at 3 deg ____ 11.6 dBi at 3 deg __ 1.5 dB When a horizontal antenna is placed very close to the ground, like 35 feet or less for a 20 meter antenna, the ground loss for the horizontal antenna increases dramatically making my original statement not exactly accurate. However, above about 40 feet, the gain difference between a horizontal and vertically mounted antenna steadily decreases. Jerry, K4SAV Joe Subich, W4TV wrote: >>The higher the antennas are, the less difference in gain >>there will be between mounting vertically and horizontally. >> >> > >Not true ... the vertical beam will always miss the "ground >gain" and will lag the horizontal antenna by three to six dB. >Over salt water the vertical beam will have more gain at >lower take off angles but its maximum gain will never equal >that of the same beam mounted horizontally. > >A good frequency for comparison is 10 meters as the height >required for a horizontal antenna to have a take off angle >similar to that of the vertical antenna becomes reasonable. >A vertical dipole at 55' (center) over perfect ground (salt >water) has a peak gain of 4.13 dB at 7 degrees. A horizontal >dipole at 55' has a peak gain of 8.08 dBi at 9 degrees (7.63 >dBi at 7 degrees). Move the antennas to 70 feet and the >gains are 4.71 dBi for the vertical dipole and 7.92 dBi for >the horizontal dipole (at 7 degrees). > >73, > > ... Joe, W4TV > > > > > > > _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread [TowerTalk] Trapped Tribanders Turned Vertical, Robert Pack, NX5M Re: [TowerTalk] Trapped Tribanders Turned Vertical, Mark Robinson Re: [TowerTalk] Trapped Tribanders Turned Vertical, Robert Pack, NX5M Re: [TowerTalk] Trapped Tribanders Turned Vertical, K4SAV Re: [TowerTalk] Trapped Tribanders Turned Vertical, Roger (K8RI) Re: [TowerTalk] Trapped Tribanders Turned Vertical, Joe Subich, W4TV Re: [TowerTalk] Trapped Tribanders Turned Vertical, K4SAV <= Re: [TowerTalk] Trapped Tribanders Turned Vertical, Joe Subich, W4TV Re: [TowerTalk] Trapped Tribanders Turned Vertical, K4SAV