[amsat-bb] Re: Simple 2.4Ghz helix plans?

31 Oct 2009

      This was the idea of the Wiki, which seemed to be a victim of infant mortality.
--
Ben Jackson - bbj@innismir.net - www.innismir.net
Sent from my Mobile Device
Andrew Rich wrote:
You know this amsat-bb needs to collect up all the info and make a forum web
page
Same old info over and over
----- Original Message -----
From: "Greg D." &lt;ko6th_greg@hotmail.com>
To: &lt;mat_62@netcommander.com>; &lt;amsat-bb@amsat.org>
Sent: Saturday, October 31, 2009 5:15 PM
Subject: [amsat-bb] Re: Simple 2.4Ghz helix plans?
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Hi Michael,
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I followed instructions from Howard Long, G6LVB, posted here a few
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years ago.  (If the archives go back far enough, it was in November of
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2001).  I don't have it electronically, but the instructions went
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something like this:
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Get a long piece of thick bare copper wire (#10 is what I think I used),
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and
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put a small mark on it every 5 3/4 inches (146mm).  Sharpie marker works
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well.  Wrap it around a
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cardboard tube that's about 1 3/4 inches in diameter.  The tube from a
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roll of paper towels works fine; the dimension is not critical.  Space the
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turns about 1 1/4 inches (32mm) apart.
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Now, here's the magic part:  once you get the helix about right, sight
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down one edge, and you'll see those 146mm marks you made in the first
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step.  Twist and stretch the coils so that they all line up, AND at the
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same time, keep the turns spaced (center to center) 32mm apart.  Take your
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time.  The diameter of the turns will take care of itself.
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For the first 1/4 turn (the matching section), decrease the pitch so that
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it gently slopes away from the reflector, which needs to be something
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around 4 or so inches in diameter.  The rest of the mechanical stuff you
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can pretty much make up yourself.  There are a lot of examples if you
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browse around the web a bit.
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Helix antennas are pretty forgiving in construction, and really cheap to
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make.
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Greg  KO6TH
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p.s.  If you already have a Wi-Fi antenna, it should work too.
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Conversely, I've found that a Helix easily outperforms those "Pringles
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can" Wi-Fi antennas that were popular a few years ago, in a Wi-Fi
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application.
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Date: Sat, 31 Oct 2009 00:03:02 -0400
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From: mat_62@netcommander.com
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To: amsat-bb@amsat.org
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Subject: [amsat-bb]  Simple 2.4Ghz helix plans?
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I threw this out there on the eham satellite forum looking for answers
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but I'll try here too.
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I'm looking for some fairly simple plans for this antenna. Everything I
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find either seems to be intended for WiFi or if it is ham related is
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full of mathematical formulas to figure length, diameter, spacing etc.
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Math was never my strong suit so I'd prefer to find something with the
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actual already computed dimensions clearly stated. Preferably in English
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rather than metric measurements. I found an article in the May/June 2008
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AMSAT Journal that looked promising but there are no hard numbers, just
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the formulas  and I don't have a calculator capable of some of the
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computations, much less being able to work them out in my head. Been a
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long time since I was in school!.. hi hi... I have a downconverter I'm
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not sure even works and I don't want to spend a huge amount of time and
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trouble to be able to test it.
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Tnx and 73,
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Michael, W4HIJ
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