Horizontally Stacked UHF Antennas (19 Dec 2013)|
|Horizontally Stacked UHF Antennas analyzed using 4nec2, including:|
a) Stacking for GAIN.
b) Stacking for a NULL along the X-Axis (which also results in TWO, SPLIT BEAMS).
Vert. Stacked A-D UHF 91XG + A-C FM-6 (14 Aug 2013)|
|Stacked Antennas-Direct 91XG UHF Corner-Yagi and Antennacraft FM-6 Antennas analyzed|
using 4nec2 to determine amount of interaction between them at various Separation Heights
(measured Boom-Boom Centers).
Since there was no noticeable degradation to the A-C FM-6, no FM Band charts are provided here.
Significant degradation to 91XG Raw Gain, F/B & F/R Ratios & SWR did not occur until Boom-Boom
Center Separation was just 1-foot. Minor degradation was observed at 1.5, 2-ft and 3-ft separation.
Negligible degradation was observed for separations of 4-feet or more.
Vert. Stacked UHF and Hi-VHF Antennas (4 Mar 2010)|
|"Typical" Hi-VHF and UHF Vertically Stacked Antennas analyzed using 4nec2 to determine minimum "tolerable" separation.|
Best vertical spacing for either combination is 6-ft or more.
For CM4228 8-Bay (with Reflector Screen) stacked on top of K6STI's 5-element Hi-VHF Yagi, impact on Gain and SWR were minimal, even at 3-inch separation.
When separation was less than 4-ft, UHF CM4228's F/R Ratio was degraded 2-3 dB, mostly at lowest frequencies.
F/R Ratio for K6STI's 5-El Hi-VHF Yagi was slightly degraded, beginning at 4-ft separation, but did not become excessive until 3-inch separation.
[Separation is measured to the bottom of CM4228's Reflector Screen.]
For kgb's 13-Element UHF Yagi stacked on top of K6STI's 5-Element Hi-VHF Yagi, the impact to Gain and SWR were minimal at even small (1-foot) separations.
However, 13-El UHF Yagi's Front/Rear (F/R) Ratio was significantly degraded when they were any closer than about 4-feet. 5-El Hi-VHF Yagi's F/R Ratio was minimally impacted.
EDIT (6Mar2010 at 5:15pm): Updated some charts with 5, 6, 8 and 100-ft separations.