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

Bob- W7LRD w7lrd at comcast.net
Sat Oct 31 00:35:24 PDT 2009



Hello Mike 

Here are a couple I have used.  Also find attached are a few pictures of past and some present antennas.  I have followed the same process and building methods for L band antennas.  I have used Drake, Transystem, Keps and SSB downconverters.  The helix is pretty forgiving in measurements.  I have the book "Antennas" by Kraus and have "tried" to follow the math and theory.  Sort of fair in that regard.  I find once I have built few and actually used them, I start to get a feel for them.   Which downconverter do you have?  There are several good articles in past AMSAT journals.  Specifically by Clair-VE3NPC, also K0VTY -Joe, he has forgotten more than I'LL ever know.  I have corresponded with them many times.  I have built many short helix feeds (5 turns) for off center dishes.  In fact that's what I used for AO-40 (sobsob).  So, good luck with your efforts.  If I can give you any hints, suggestions or whatever, just drop me a email. 

73 Bob W7LRD 


----- Original Message ----- 
From: "Michael Tondee" <mat_62 at netcommander.com> 
To: "Amsat BB" <amsat-bb at amsat.org> 
Sent: Friday, October 30, 2009 9:03:02 PM GMT -08:00 US/Canada Pacific 
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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