One 15/40 combination that seems to work in proximity is when the 40
is made of Force 12 folded elements (the "N" series of F12 40m beams).
The folding causes the secondary resonance of the 40 N elements to
move to 18 MHz, significantly reducing the "pull" that the 40 element
has on 21 MHz.
----- Original Message -----
From: "RICHARD BOYD" <ke3q@msn.com>
To: <towertalk@contesting.com>; "Jose Castillo" <N4BAA@cox.net>
Sent: Saturday, August 07, 2004 2:53 PM
Subject: Re: [TowerTalk] STACKING
> As I often do, quoting others more expert than myself, the main
issue seems
> to be detuning of the 15M yagi by the 40M yagi. I asked W3LPL how
far a 15
> and a 40 should be apart. He thought 30' would be good.
>
> Most of us would not be able to get that much distance and still
have them
> both rotating on a mast at the top. One of them would either have
to be
> sidemounted lower down the tower, or you have to accept the
potential for
> degradation of performance by having them closer.
>
> In the real world, many people put their tribander and 2-el 40
within a few
> feet of each other and are satisfied with the performance.
Obviously, more
> is better. While it's a different situation, different bands, I
have 20 and
> 15 yagis 8' apart and they've always worked well. It's the
> interaction/degradation problem that causes people to pair 40/10 and
20/15
> on two towers -- alternatively, 40/20 and 15/10. But not 40/15
together.
> With a tribander for 20/15/10 that's not the situation you have. 15
is the
> one that suffers, typically.
>
> Probably 6-8-10' separation between the tribander and 40 is worth a
try and
> see if it works satisfactorily for you. The resonant point and/or
pattern
> of the 15 may change.
>
> You might try putting up the tribander first and do good performance
plots
> across each of the three bands. Then put up the 40 at whatever
separation
> you can achieve and repeat the plots to see what effects you can
observe.
>
> 73 - Rich, KE3Q
>
>
> ----- Original Message -----
> From: "Jose Castillo" <N4BAA@cox.net>
> To: <towertalk@contesting.com>
> Sent: Thursday, August 05, 2004 7:54 PM
> Subject: [TowerTalk] STACKING
>
>
> > Hello,
> > I am planning on purchasing a SteppIR 4 element yagi.
> > I also have a Force 12 240/230 (2 ele on 40 and 30 meters)
> >
> > How high above the SteppIR would be adequate?
> >
> > 73
> > Jose - N4BAA and YI9BAA
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless
> > Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
with
> > any questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless Weather Stations", and lot's more. Call Toll Free,
1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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