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

Alan VE4YZ ve4yz at mts.net
Sat Oct 31 08:38:13 PDT 2009

I'll come back to my recommendation of the standalone HelixCalc.exe by Jason
Hecker or his web app

Web  http://www.wireless.org.au/~jhecker/stuff/Helix.php

Standalone http://www.wireless.org.au/~jhecker/helix/HelixCalc.zip


Most other web apps allow for 2 inputs - frequency and number of turns.  You
then have to do a lot of measuring on a tube of a diameter dictated to you
to wind with the correct pitch and allow for the coil to spring open to a
larger diameter.

The Hecker program allows for multiple inputs and most important for the
DIYer IHMO is the tube diameter you plan to use.  PVC pipe, conduit, mailing
tube, dowel or whatever - you use what you have or what you can find at Home
Depot close to you initial calculations.  You can also play with diameter, #
of windings etc to see how they effect the theoretical gain.

Print out the form, wrap and tape it on your tube and then wrap the wire
along the printed lines.  No calculations and minimal measuring.  After
testing your first wire wrap and measuring the amount that the coil springs
open you can enter that new diameter in the calculator.  i.e. a 2" O.D. PVC
pipe will not give you a 2" I.D helix - it will be slightly larger as the
coil springs open unless you use standoffs on each loop a la W7LDR helix

As to the comments on the Wiki... Until it happens... Google!  The AMSAT BB
archives are searchable.

> -----Original Message-----
> From: amsat-bb-bounces at amsat.org 
> [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Michael Tondee
> Sent: October 30, 2009 11:03 PM
> To: Amsat BB
> 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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