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

Andrew Rich vk4tec at tech-software.net
Sat Oct 31 00:47:26 PDT 2009


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." <ko6th_greg at hotmail.com>
To: <mat_62 at netcommander.com>; <amsat-bb at amsat.org>
Sent: Saturday, October 31, 2009 5:15 PM
Subject: [amsat-bb] Re: Simple 2.4Ghz helix plans?


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