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
Why?
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 construction.
As to the comments on the Wiki... Until it happens... Google! The AMSAT BB archives are searchable.
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@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 _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb