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Re: Quadrifilar Helix Antennas for 2400 MHz with English text




>
>You are mentioned in the reference of my article
>"Experimental Investigation with Quadrifilar Helix Antennas
>for 2400 MHz" that was published in AMSAT-DL Journal
>december 2003/January 2004
>
>I would like to get your comments.

Hi Dom,

No problem...I built the quadrifilar from the article in the Experimenter's 
Manual about 15 years ago, specifically to use on the low orbit birds, and 
it works very well.  It took about five iterations to get the swr to 
1.5/1.  And from the final dimensions it scaled to the same swr on 2 
meters.  I also built one for a friend of mine that lives on a sailboat, 
for 137 Mhz...He claims it works better than some of his neighbors that 
have commercial antennas that they paid big bucks for....

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

the file quadfil1.zip has pics and dimensions, old black and white, but 
still usable!

Also on the site I just placed the file 2400quad.jpg that I used on O13 2.4 
downlink with good results....I determined, empirically, ~140° beamwidth 
using the low orbit satellites.  It worked just as well as a helix on a 
70cm round dish I was using at the time...

Be aware, all of my "testing" is done with ear and eyeballs!!



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


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