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Re:Arrow 14 el 70CM RHCP,or what to do waiting for ao40 to show up



I used this back on FD 2002:

http://webpages.charter.net/acito/uplink1.jpg

...and I had done all the research to make sure I had done it correctly.
I know I asked what the correct orientation should be in the AMSAT-BB,
but a few minutes of looking in the archives and I can't find it...
the subject would have been "crossed yagis" or something.

Anyway, the first edition of the Satellite Handbook has the necessary info.

In this case, I used two matched yagis with gamma matches, and a
standard stacking harness (equal multiple 1/4 wavelengths on each side
of the T in 75 ohm coax?) from Cushcraft --- found one surplus,
don't think they sell them any more.

What was great about this vs. the Gulf-Alpha I have now is that it packed
flat
in the back of the Subaru.

The right hand (your right) yagi is positioned 1/4 wavelength in front
of the other along the boom line. The right hand yagi has it's match
element up (not clear in the photo), and the left hand yagi has it down.

Yes, those are spring clamps, screwed to a piece of oak, screwed
to a steel electrical box cover, with a hole in the center so I can
mount it onto the camera tripod. Can you say "home depot special"?

Assuming what I did in the picture is correct, in the case of the
Arrow (very slight boom offset) looking from behind, I guess it should be:


 \      //
  \    //Short end of harness to this yagi
   \  //
    \//
    /\\
   /  \\ Long end goes to this yagi
  /    \\
 /      \\

....to give RHCP.

I can't believe that the 6mm offset will make that much
difference. My "elliptical" set-up seemed to work fine. :-)

Can someone check my work that this correct?

(we should get Arrow to offer a phasing harness for their antenna)

Bill
W1PA
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