Nitin,
When stacking antennas for different frequencies and you wish to
estimate the effect of, say, a 2m antenna on a 70cm antenna, you should
consider the capture area of the 2m antenna at 70cm, *not* at 2m.
Despite the physical size, the capture area is very small. That means
you can put the antennas much closer together than many people think.
WA5VJB did some measurements for 900MHz and another band which
illustrated this, and presented the results in a lecture to the UK
Microwave Group some years ago. He found he could put the antennas
almost touching with little effect on the radiation pattern. I did some
Eznec simulations for 2m and 70cm crossed yagi antennas spaced
horizontally at distances from 2.0m down to 0.8m which gave similar
answers. I have the pictures in a powerpoint file which I've emailed to
you directly as I don't know if this list supports attachments.
I built the antennas but then moved house before I could put them up. I
still haven't got there!
73
Chris
On 01/07/14 18:47, Nitin Muttin wrote:
Friends,
Need some help. I am planning to stack two 2 meter Cross Yagi and two 70 cms
cross yagi on a H frame. Can some one guide me on the horizontal and vertical
stacking distances that I need to maintained. I have some information for
example from http://www.directivesystems.com/STACKING.htm but confused what
should be the final configuration.
73
Nitin [VU3TYG]
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