[Antennas] Antenna placement
Dave Shrader
[email protected]
2002年10月01日 15:48:10 -0400
Any antenna within the near field of a second antenna and in the same
polarization, [2 or 3 wavelengths] will interact by the physics of
mutual impedance [the physics of a parasitically excited Yagi]. The
greater the separation the less the interaction.
That's the operating principle. However, many people use multiple
antennas with about 1/2 wavelength spacing with fair to good results. I
had a center fed doublet mounted below a beam and it would cause the
VSWR on the beam to vary as I rotated the beam!!
You can mount a vertical above the beam with minimum interaction because
it's a combination of vertical and horizontal polarization and should
have -20 to -30 dB of mutual coupling.
Deacon Dave, W1MCE
Manager, Textron Antenna Range, retired
--------------------
Tom wrote:
> I have recently acquired some remote antenna switches and want to put up
> antennas for each band that I use. Currently I am only have a
> technician license so I want to put up a 6m vertical, a 2m vertical, a
> 70cm ground plane, and a 2m beam(probably a yagi).
>> My question is since I am only using one of these at a time, can they be
> spaced relatively close together, or how much separation do they need?
>> Can I put a vertical on the same mast as the beam?
>> Thank you.
>> Tom
> KD5TIE
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