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RE: Helix Construction



Hi Jesse,

Check out http://users.bigpond.net.au/jhecker/ and look for the link
to the HelixCalc program. Here you can calculate the desired helix
antenna and can print the "PVC wrap-around paper" you're looking for.

Good luck!

73 de Andre PE1OIG.
------------------------------------
Andre Theelen   PE1OIG   QTH: JO20WX
e:pe1oig@pe1oig.net w:www.pe1oig.net


-----Original Message-----
From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
Behalf Of Jesse Morris
Sent: Saturday, March 09, 2002 0:24
To: amsat-bb@AMSAT.Org
Subject: [amsat-bb] Helix Construction


Good Evening to All,

Last year when I was working on a helix antenna for AO-40 I picked up a
nifty idea on the web for a method of  accurately maintaining the spacing
and pitch of the antenna when wound on a piece of 1 inch PVC.  It
involved preparing a plain piece of paper with a series of boxes on it. 
The X axis (vertical lines) corresponded to the circumference of the PVC
and the Y axis (horizontal lines) corresponded to the winding spacing. 
Drawing a diagonal line from one corner of each box to the other
corresponds to the pitch.  (Depending on which way the diagonal runs it
works for RH or LH.)  If you warp the piece of paper around the PVC you
have a perfect pattern for winding the helix. I think it was originally
done with a CAD program but it could really be done by hand.  I can't
describe the process nearly as well as the originator but a disk crash
some time back caused me to loose the original message so I don't know
the source of the idea.  I think it was from one our friends "down under"
but I'm now sure.  I would like to recover the ID of the originator so I
could give proper credit with I pass the idea along.  If anyone knows the
originator of the idea I would appreciate the info.

Thanks and sorry for the BW.

73's de Jess - W4MVB
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