Greetings TowerTalkians,
There have been some questions recently regarding how far apart a 6 meter
beam should be stacked with an HF antenna, such as a tribander or
monobander. Although I don't have a good AO model for the TH7DX or TH11DX
right now, I created an AO model for the 64DX 4 element 6 meter beam
(setting #1) and merged it with a model for the 204BA (CW setting). Here
are the results at different spacings at 50.5 MHz:
Spacing Gain@0 Gain@peak Elev@peak Impedance F/B
2 feet 9.03 dBi 9.17 dBi 8 degrees 27.8+j1.5 14.1 dB
3 feet 9.12 dBi 9.35 dBi 10 degrees 31.0-j0.9 13.7 dB
4 feet 9.24 dBi 9.54 dBi 12 degrees 32.2-j1.8 14.2 dB
5 feet 9.39 dBi 9.74 dBi 14 degrees 32.8-j1.6 15.3 dB
6 feet 9.57 dBi 9.92 dBi 12 degrees 33.3-j1.1 16.5 dB
7 feet 9.75 dBi 10.09 dBi 12 degrees 33.9-j0.4 17.9 dB
64DX 9.73 dBi 9.73 dBi 0 degrees 34.5+j0.4 17.1 dB
alone
The 64DX was above the 204BA. Gain@0 is the gain on the horizon (at 0
degrees elevation). AO 6.5 was used with 10 seg/halfwave.
Although the 64DX should work as close as 2 feet from the 204BA, it does
lose 0.7 dB gain and 3 dB F/B at this spacing. I still recommend 4 to 5
feet separation.
73 Roger WB0DGF
Telex Communications, Inc.
http://www.hy-gain.com
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