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

[Ben Jackson]

This was the idea of the Wiki, which seemed to be a victim of infant mortality. 

--
Ben Jackson - bbj at 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." <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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