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Re: Can someone point me to a simpleS-bandhelixconstruction article?



Hi John

> http://www.wireless.org.au/~jhecker/helix/

An interesting article. I noticed that although the writer discusses that
the PVC didn't get hot in his microwave oven (inicating it's not lossy), the
detuning effect of the PVC dielectric isn't discussed. This was one of the
major problems I had when using PVC pipe as a former. If you can take the
dielectric effect into account (assuming all PVC pipes have the same
dielectric properties), then great. Another common fault is to use a
non-central support. 

Had I known the above tips, I would have saved myself weeks of fruitless
efforts!

Helices are very forgiving antennas in general. The things to pay attention
to detail on are the former and the matching section if you're interested in
picking up weak signals.

One further thing - the amount of RF at 2.4GHz now that wasn't there seven
years ago is astonishing. The pick up from sidelobes of the helix may make
performance disappointing for satellite use.

I have a number of articles on building helices including:

http://www.g6lvb.com/60cm.htm#PerfectHelix
http://www.g6lvb.com/quadruple_helix.htm

Cheers, Howard G6LVB

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