L. B. Cebik wrote:
>
> Extensive modeling studies on 5-band 2-element quads shows that the loops
> need to be closed when not in use for minimal interaction. Opening the
> driven element loops when not in use presents extensive interaction. As
> well, for a 5-band quad, or even a 3 band or just a 10-20 meter quad,
> separate feeds are needed to prevent serious pattern distortion. The 1/4
> wl match line (or even just any line) from the driven element loop to the
> remote switch is a good way to effect the closure electrically while
> leaving the loop "physically" open.
I have juse fed all 3 elements with a common coax on a 4 element
10-15-20 meter quad. Are you saying this is bad? I am getting ready to
put it back up. I use a balun at the feed point. How will this affect
it?
Would I be much better to use 3 baluns and a switchbox? Do I need an
insulated switchbox to let both the shield and center conductor float or
is an aluminum box OK with the center conductor floating?
Does the balun act as a short so that I would be better off with
ferrites over the coax at the feed points?
Chuck, KE5FI
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|