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HT antennas on cover of QST



This months QST cover photo show several kids holding
garden-fence reflectors for their HT's and listening to the
many LEO satellites.  (I never knew of the photo and
it took me a long while to even remember where it was!)

Anyway, I have been taking these antennas to  groups
for years.  Back in 1998 when I first built them, there 
were 18 working AMSATS and 11 that you could hear
on these wire antennas.  Now there are only 2 or 3.

Anyway, the idea was to hold the HT at the focal point
of a garden fence piece of screen and with the 10 dB 
of gain, ANY HT could hear the satellites.  No
dimension is critical.  Just bow the screen so that
the HT is 6" from the back and 1 foot side to side
and you have a parabola.

Devise whatever mounting method to hold it that
way and you have a great RECEIVE system for
UHF downlinks (which is all I wanted for these demos)

Problem is the screen's I used were about 18" by
2 feet and the spider poles and foldable handle were
still 2 feet long when folded.  ALthough I could stack
several of these, they were just bulky to carry.  I had
 planned on  writing them up, but since there never
was a convenient carrying case, I never got around 
to it.

One day, I did take one of the screens and cut it into
3 pieces (then bend the wires as hinges over each
other so that the three screen panels would fold on
top of each other and fit in a briefcase.  But now, the
simple "stressed" reflector pole and handle was 
useless and needed a plywood parabolic mold to
then hold the reflector into the correct shape.  That
was more wood work and so I just never got around
to finishing it.

But the point is, bending into a parabola is just making
an optimized corner reflector and the resulting 10 dB
of gain is MORE THAN ENOUGH for handhelds to 
hear the LEO's all the way to the horizon..  So get some
fence wire and start playing!  (though the reduction in
the number of satellies from 11 down to 2 or 3 also
deminishes the incentive these days...

But with one of the ALL-MODE HT's like the Kenwood
TH-F6, you can even hear AO-7 and FO-29!

Oh yes, and KIDS love it.

(The red-head on the right in the photo is #1 son.  My #1
(daughter was off reading a book apparently when this
(photo was taken)...

de WB4APR, Bob

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