Wes Stewart wrote in message . ..
On 15 Nov 2003 11:00:19 -0800, (Art Unwin KB9MZ)
wrote:


|Can you tell me where I can find what the orientation of coil cross
|section does for efficiency ?

Michaels ("Loading Coils for 160-Meter Antennas", QST, April 1990, pp
28-31) might help.

|There are circular cross sections, edge wound cross sections and also
|the ribbon type that Collins uses where the ribbon is coiled on a
|adjacent coil former, why did they choose this method?

I believe the Collins ribbon inductors were designed for variability,
i.e., tunable without any sliding contacts as in roller inductors.

|I am pursuing efficiency, reduction of losses and Collins have a great
|reputation so which form is the state of the art especially with
|corner flux density.
|Another question is that if we split up an inductance into two parts
|does the form factor include the summation of inductances or does the
|distance inbetween
|where coil linkage is not fully formed affect efficiency for the
|worse.
|Discussion like this thread hopefully will enlarge our education to
|see if such things matter . Another question I struggle with is to put
|another element inside the coil where there is max flux density but
|again it can't be resolved by modeling. With the multi antenna experts
|onboard it is always a possibility that a modicom of information will
|be provided that will benefit all.
|As far as inductances, all is not known to my mind and I always would
|like to be privy to more information, and not because I want to build
|a whip

Another interesting reference is Rhea ("Filters and an Oscillator
Using a New Solenoid Model", Applied Microwave & Wireless, November
2000, pp 30-42) In a nutshell, his premise is that the classic
inductor model is in error, particularly with respect interwinding
capacitance.

Some other articles that should be read by all participating in this
thread are by Cebik.

http://www.cebik.com/amod/amod13.html

http://www.cebik.com/amod/amod14.html

Thank you for those references Wes. I really didn't expect to hear
from you again. I now have the computor program to simulate my actual
antenna so efficiency is now of major importance ,I can up my
efficiency to 50 per cent
by hanging a wire down from the dipole ends which I am not comfortable
about
and would rather aproach the coil for loss reduction and go for a beam
setup
by using the radiation efficiently by making it fully directional
stead of figure 8 form
and hopefully I can get those extracts

Reg I tried to enter your page once but I am so computor incompetant.
Looked at a tank circuit today and it was wound flat ribbon form!

Looking forward to looking at this fresh info
Many thanks to both of you
Art