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Helix for 70cm?



Group

A close inspection of my old KLM 40CX shows that the driven elements have
somehow split where they bend to make the loop. Another problem seems to be
the polarity switch - when switching between RH and LH polarization with
FO-29's downlink and AO-40's uplink, the difference is very slight about 1
S-unit at best so something isn't right.

With that said, I was looking for a cheap way to optimize my 70cm AO-40
uplink capabilities and looked at the Helix design by Mike Cook ( AF9Y )
http://64.119.173.164/radio40.htm . The gain is impressive and the parts are
relativily cheap. According to Mike the cost should be around $30. The gain
on the 10 footer is 15.9dbc.

Having no experience with the helix, it seems that the tough part would be
shaping the elements to keep within the physical tolerances specified.  I
was wondering if anyone is building high-gain circular polarized antennas
like this on the commercial market? If not, it looks like I'll have to build
my own.

Any suggestions?

Tony - AA2AE

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