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