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Old July 15th 03, 07:13 PM
Loopfan
 
Posts: n/a
Default Shielded Loop - Velocity Factor?

I have a few more questions, but first I'd like to thank everyone for
their feedback. After doing some usenet searching, it seems that I am
retracing the footsteps of those from about 1995 onwards. I'd like to
thank W7EL, W8JI and others for making my head hurt. grin I feel like
that character in Close Encounters making a mash-potato mountain in his
living room....

I have been cutting my coax loops to less than 1/10th of a wavelength
and also taking the velocity factor of the cable into account. After
your help with analyzing transmission lines, and proving for myself that
the outside shield is the antenna by way way of being able to attenuate
it with an RF choke, I am now wondering if I should *NOT* take the
velocity factor into account and make my loops with disregard to the
velocity factor? Or does the jacket contribute to the velocity factor
of the outer-surface of the cable?

Question 2: Have we come to any conclusions about how the current gets
from the outer-skin surface of the shield to the inner-skin surface of
the shield? I don't want to rehash an old topic, so I'll be just as
happy to say that it merely *does*. I'm wondering if there is a field
set up on the outer skin edge that encompasses the inner-skin edge and
transfers current that way, or can I view the inner and outer skins as
more or less the same conductive skin surface that has a 180 degree bend
in it so that its analogous to the inside and outside being the same
sort of "outer" skin? Looks like I'm confusing myself...

I'll be happy to do more usenet message searches if that will prevent a
total flareup of the same old topic.

Thanks and 73
Brian