Lower frequency antenna elements act as inefficient reflectors to
the higher frequency antennas and will skew the vertical pattern
of the higher frequency antenna.
A good rule of thumb is 0.2 WaveLengths minimum between
antennas, at the higher frequency. For 6 meters, this comes to 4 ft.
Of course 6 ft is even better.
Higher frequency antennas are generally (almost) invisible to lower
frequency antennas if the frequency difference is more than 10% or
so, similar to "non-resonant" guy wire lengths.
de Tom N4KG
On Tue, 09 Nov 1999 20:08:50 -0600 Bill Aycock <baycock@HIWAAY.NET>
> Opinions wanted
> I have an ATB34 tribander at about 50 ft, mounted on a 2" mast just
> the tower. There is about 3-4 ft of additional 2"mast above there,
> and a
> reduced size mast for another 2 ft. I plan to put a 3el Yagi for 6M
> on the
> smaller mast section, above the tribander.
> If I just leave the tribander where it is, and put the 6m on the
> mast- the range of spacing is about 3.5 to 6 ft.. I can reduce this
> elevating the tribander, or increase it a little by lowering the
> The obvious questions are: 1. what spacing will probably be best.?,
> 2. is
> there a spacing I sould avoid?, and 3. should I leave the booms
> lined up or
> put them at 90 deg?
> The ATB34 is an earlier incarnation of the CushCraft 4el Tribander.
> appears that all the changes were to make it cheaper to build- like
> off the Balun) But this old one works quite well.
> Thanks for any comments- Bill- W4BSG
> Bill Aycock --- Persimmon Hill
> Woodville, Alabama, US 35776
> (in the N.E. corner of the State)
> W4BSG -- Grid EM64vr
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