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Old April 4th 06, 07:15 AM posted to rec.radio.amateur.antenna
 
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Default Current across the antenna loading coil - from scratch

but we can not
use electrical degrees to 'splain the behavior of coiled antenna wire?


I can see how problems could arise going by the length of coil
wire length in degrees only. Lets say you run a coil 1 foot from the
base. Lets say that coil uses 25 turns to tune a particular frequency.
Now, move the coil up 2 ft higher, and see if that same 25 turns will
tune the same frequency. It won't. You will have to add a few more
turns.
So just going by the total mast plus coil wire length in degrees could
vary
all over the map just by changing the position of the coil. As you
raise
the coil, you will have to add more and more of "degrees" of wire to
tune the same frequency. :/
Dunno...There may well be some variation of current from the bottom
vs the top of the coil, but overall, I still view the operation of a
loading
coil as a "lumped" mechanism overall.
Even if you all decide that the current changes, or it doesn't , it
ain't
gonna make a hoot's worth of difference in the design of mobile whips.
I think it's an argument that has no real value to me as far as mobile
whips go. The performance of all the various coil heights, and configs
have been well known for years. Coil current taper or not.
I just don't see the facination with arguing about something that even
if
decided one way or the other, still won't make any difference in the
final
antenna design. Oh well...Continue the tail chasing excercise....
I'm outa this one... One post is all I will waste on this subject..
I couldn't mount my coil much higher if I wanted to... Current taper or
not. :/
MK