Re: [Paddlewise] Kleppers, visibility and wine casks

At 06:19 PM 08/15/1999 +1000, Peter Osman wrote:
>In my navigation class yet more yachties asserted how difficult it was in
>general to see kayaks and the instructor suggested that running a metallised
>wine cask liner up a mast would make a good radar reflector. For kayaks this
>sounds a bit bulky with problems of wind resistance, so I'm wondering is it
>worth using a radio mast to enhance radar and optical visibility by
>attaching a colored pennant made of wine cask liner. Does anyone know how
>big such a pennant would need to be to give a decent radar signal and would
>the pennant interfere with radio transmission from a VHF radio using the
>antennae? If it worked this idea might be appropriate for Kleppers, which
>are unlikely to be rolled.
>
>Are there good reasons not to do this?

Hi Peter et al.
First, any conductive material placed in the near-field an antenna will
de-tune it. When placed near (or in contact with) the tip, it will lower
the resonant frequency of the antenna by an amount dependant on how much
and how close. There is not really all that much metal in a metalized mylar
film, so the effect will probably be fairly insignificant. For the same
reason, I'd expect the mylar film to be a not particularly effective
reflector of microwave (radar) radiation. The best suggestion I can offer
is to try a with / without experiment, coordinating the efforts with your
yachting friends on VHF. That might give some indication of how much effect
the pennant is having on your antenna as well. 
I will offer another idea that might be worth a try. Find a childs pinwheel
toy made of a metallized plastic, or better yet, make your own from some
thin (.002 in) stainless steel shim stock. Mount it to an old fishing rod
with the handle removed, and rig a way to step it into your deck. The
spinning pinwheel will offer relatively minimal wind resistance, and should
provide some pretty interesting radar (and solar) reflections. If nothing
else, it will provide endless amusement for your fellow paddlers. Let me
know if it works!
ByeBye! S.
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