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Message: 5 Date: Fri, 02 Nov 2007 10:33:09 -0700 From: Dave Guimont dguimon1@san.rr.com Subject: [amsat-bb] Re: Quadrifilar Helices To: "R.Haighton" ve3frh@cogeco.ca Cc: amsat-bb@amsat.org Message-ID: 200711021733.lA2HX9s4008456@ms-smtp-03.socal.rr.com Content-Type: text/plain; charset="iso-8859-1"; format=flowed

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The Satellite Experimenters Handbook by Martin Davidoff K2UBC (1990 Pages 8-15 & 16) and it's successor The Radio Amateur's Satellite Handbook (1998 pages 10-13 to 10-15) both have details of this antenna, its use and its construction. I recommend this book to all satellite experimenters and users, it may be nearly 10 years old but the principles and information contained therein have not changed.

Robin Haighton VE3FRH Immediate Past President AMSAT

That's exactly where I started, Robin, on page 6-20 of the original edition. But Maxwell's measurement produced a horrible VSWR.....I saw Marty later on at a convention, and I believe he said the same thing happened to him...

It took me 4 iterations to get the antenna flat with no matching device...I of course did it at 435. But those dimensions translated very successfully to 2M satellite, 2M repeaters, and believe it or not to 2.4 gigs....In front of a dish, of course!!!

I had seen other pictures of the antenna, and was very interested prior to Marty's excellent depiction of the construction details...

I used a combination of 435 and 2M versions fixed at about 45?, and rotated in AZ only and worked very well with strong signal birds...

Quadfilxxxxxxxxx has the dimensions for the 3, but the 2.4 gig computation is left as an exercise for those interested.

http://home.san.rr.com/doguimont/uploads/

Nice to hear from you, Robin....R U active on any of the birds??

        73, Dave wb6llo@amsat.org
                Disagree: I learn....

           Pulling for P3E... 

I found WB6LLO's 435 version easy to reproduce with good results.