stack observations - query

C. Logan Dietz (KE5FI) ke5fi@wt.net
Tue, 11 Feb 1997 18:32:27 -0800


Andrew Williamson wrote:
> 
> In message <33000DDF.89F@westky.com>, Bud <k4isv@westky.com> writes
> 
> >I submit the following as "general rules" I have observed in working
> >with stacked yagis.  To be sure, there are exceptions and no one antenna
> >is BEST. The following assume properly installed, tuned, phased, spaced
> >etc... :
> 
> >6) swr of a properly phased stack is lowest when in the same direction
> >and highest when 180 deg. apart
> 
> Hi guys (and gals),
> 
> A quick query on Bud's point number 6.  Just how much does the SWR vary
> when rotating the top antenna relative to the bottom one.  Hopefully in
> the next 12 months we will be stacking yagis at GI0KOW (top one
> rotatable only) and was wondering about this.  The phasing will probably
> be done with Dunestar boxes.  My ETO 91B isn't to keen on any SWR over
> about 1.5:1, so would the SWR fluctuation when rotating be a problem?
> 
> Not sure if the number of elements would make any difference, but we
> will be stacking 6's on 10 and 15M, and 4's on 20M.

I had a top rotary 10 meter beam at 85' and a NW lower fixed at 45' and a 
NE fixed at 40'  I did not even notice the SWR variance when I rotated 
the top beam.  This arrangement worked VERY well.  I am looking forward 
to many stacks at my new QTH.

Chuck, KE5FI


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