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Re: [CQ-Contest] DX Sprint is a good idea

To: <cq-contest@contesting.com>
Subject: Re: [CQ-Contest] DX Sprint is a good idea
From: "Nat Heatwole" <nat@ajheatwole.com>
Date: Tue, 23 Mar 2004 00:12:28 -0500
List-post: <mailto:cq-contest@contesting.com>
> 50 db gain?  Man, what kind of antennas do that?  Assuming a single
> beam did have 10 db, doubling that with 2 would give 13 db and adding
> another 2 would bring it up to 16 db.  You would need one heck of a
> stack to get 50 db!!  You don't get 10 db every time you add another
> beam.
> Tom W7WHY

I think that you misread my post. I wasn't including the gain from the
presence of the additional antennas. If I had, my figure would have been
closer to 55 dB. I was talking about the *effective* gain that results
from the ability to control the takeoff angle. For example, if one has a
beam at a given height the beam will have nulls at various takeoff
angles. Being able to control the takeoff angle allows one to control
where those nulls are, i.e. not at the angles where the propagation is.
When you factor this into the calculation, stacking can give you as much
as 40 dB *effective gain* over a single yagi where the nulls are not
moveable in this way.

My figure of 40 dB came from a product review of WX0B's StackMatch that
was published in either QST or CQ (can't remember which). I think that
K5RT may have been the author, but I'm not certain about that . Whoever
wrote the article had stacked Hy-Gain tribanders at 100/50ft and
discussed their performance with the StackMatch during SS.

Anyway, this discussion is really more appropriate for TowerTalk, not
CQ-Contest, but I think KQ2M really encapsulated my point when he said:
"hills are good, salt water is better, anywhere you can put up stacks is
the best."


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