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Old February 25th 10, 05:08 PM posted to rec.radio.amateur.antenna
steveeh131047[_2_] steveeh131047[_2_] is offline
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First recorded activity by RadioBanter: Jun 2009
Posts: 31
Default Two coax as substitute for open line

On Feb 25, 4:51*pm, Owen Duffy wrote:
Owen Duffy wrote :

steveeh131047 wrote in
:
The application is no secret - the first paragraph in my linked page
explains it.


Steve,

Another thought comes to mind, and that is a pair of rectangular
conductors, preformed to the parabolic like shape and screwed togeter with
insulated fixings.

You could achieve the Zo you seek with say 20mm wide flat with manageable
spacing... however it would be a water trap to some extent (just like LP
feeds using twin booms).

Owen


Owen,

Thanks for the suggestion - water shouldn't be a problem because this
"band interconnect" TL can be installed within the hexbeam centre post
where it would be protected. One chap has already fabricated a "square
coaxial" version - second photo, he

http://lema.epfl.ch/images/stories/L...HB9MCZ_wb.html

but that will be beyond the capability of many constructors!

It's not a major issue - most constructors simply use RG213; but some
find the physical terminations "fiddly", especially if you try to
assemble it inside the centre-post for neatness and weather
protection. I'm pretty sure that twin line using the right gauge ecw
with teflon tubing on one of the wires would be about the correct Zo
and easy to fabricate. It's just another thing on my "to do" list - a
list which seems to get longer rather than shorter

73,
Steve G3TXQ