N4ZR wrote:
Freq Ht R X SWR Gain TOA F/R
14.200 40 26.82 1.64 1.867 16.34 14 20.74
14.200 45 26.75 2.04 1.873 16.73 12 20.01
14.200 50 27.71 2.40 1.810 16.99 11 18.76
14.200 55 28.84 0.91 1.735 17.25 10 16.32
14.200 60 28.02 -0.54 1.785 17.53 9 17.10
14.200 65 26.98 -0.87 1.854 17.72 9 18.37
14.200 70 26.28 -0.73 1.903 17.81 8 19.33
14.200 75 25.86 -0.44 1.934 17.81 8 19.45
14.200 80 25.65 -0.12 1.949 17.82 7 17.76
14.200 85 25.66 0.18 1.949 17.83 7 18.99
14.200 90 25.76 0.22 1.941 17.81 6 20.74
I would add a few points:
1. Gain change is negligible from 65'-90' (.93-1.29wl)
2. These are probably for a fixed dimension. Performance
of the stacked system can be improved by optimization (e.g. YO7)
in the stacked configuration, not the individual antennas.
Example: http://users.vnet.net/btippett/yagi_optimizer_7_0.htm
3. TOA is probably the most important consideration
and should be modeled with N6BV's YT or newer HFTA.
Example: http://users.vnet.net/btippett/terrain_&_toa's.htm
4. The whole idea of stacking is to cover as much of
expected TOA's as possible with all possible combinations
of antennas. Learning when to use various combinations
during an opening is another issue by itself. See note
under the first graph in #3. above.
73, Bill W4ZV
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