[Antennas] Multiple antennas

[Dave Shrader]

I haven't  modeled your setup but several quick thoughts jump to mind.

1] The double extended Zepp has about 2+ dBd gain to maybe +3 dBd gain.

Your antennas would have some mutual coupling. The impact of the mutual
coupling on a large array could increase or decrease gain depending on
the actual phase of the induced currents. However, feeding two elements
directly divides you power by two [-3dB]. Feeding all three elements
directly would divide the input power to each section by almost 4.8 dB.
My pre-judgement is that the mutual coupling would not be sufficient to
recover the power density off of the major lobes of each section.

Quick estimate: You would have an almost omnidirectional horizontally
polarized antenna at about 1/2 S unit down from a dipole. Personally, I
would keep them individually switched and get gain in the desired
direction.

Dave, W1MCE

Robert Wilder wrote:
> 
>   I would like to pose a question.  I have room to put up three (3)
> identical double extended Zepp antennas.for 40 meters They would be 120
> degrees from each other in the shape of a diamond.  Each antenna will be
> fed with an identical length of ladder line terminated in a 4:1
> balun.   Each balun will be fed with about three feet of coax to an antenna
> selection switch (like the Ameritron RCS-8V) and in turn to a single coax
> lead back to an antenna tuner in the shack.   I know that this would give
> me identical patterns but 120 degrees apart which pretty well cover the
> world.  Now the question.  If the switch can be made to select a pair of
> these antennas or even all three at one time, what will happen?  That
> is:  Pattern(s), Impedance, radiation resistance, etc.  Contact me off list
> or if you feel others might be interested via the list.
> 
> 73
> 
> Bob Wilder, AF2HD/AFA2HD
> 6032 Idlemoore Court
> Theodore, AL 36582-4036
> 251-653-5274
> http://home.earthlink.net/~bwild
> All incoming and outgoing messages
> virus checked with AVG version
> 6.0.370 updated 6/5/2002
> 
> - - -
> 
> Your moderator for this list is:
> Larry Wilson KE1HZ antennas-owner@mailman.qth.net
> _______________________________________________
> Antennas mailing list
> Antennas@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/antennas