>The other question is why should it be placed 3 feet from the VHF
antenna?
>Again, the VHF antenna would presumably not be used at the same time
as the
>ELT antenna.
At frequencies around 118-137 MHz, 3 feet represents about half a
wavelength. Another antenna (or, indeed, any conductive material)
introduced within half a wavelength of, and in the same plane as, an
antenna will act as a parasitic element that will affect the radiation
pattern of the original antenna. The size and spacing of the
parasitic element will vary the degree of effect but it will almost
certainly produce a shift from oni-directional to a cardoid pattern
introducing a null in one direction.
Peter Barwick
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