"Reg Edwards" wrote in message ...
Art, I should have added - you must take the opportunity to increase
conductor diameter. You have twice the length of coil with only 70% of the
number of turns to wind along it.

There is NO other way to increase Q of a coil while maintaining the same
inductance.

If you think about it it's fairly obvious.

Reg
my mind is not as alert as yours, many times I will argue for what is
obvious at the time but after several days am forced to change my
mind.
This is a similar case where I am mindful of the bad effects of
capacitance
so I am heading towards keeping the same outside area but reducing
capacitance raising surfaces which by flattening the coil places
the turns closer together.
Since the coils are so large the design forces me to place one side of
the coil close to a fibre glass support which is not good either plus
if I make the turns larger and lighter it will become flimsy unless I
add dielectric loss type supports which may well overtake the losses
in the present design.
All most interesting which is forcing me to think about such a simple
thing such as inductance.
Cheers
Art

---
Reg

"Reg Edwards" wrote
If both coil diameter and length are doubled, and number of turns are
reduced to 71% of the number you started with, then you will end-up with
the
same inductance as before but the loss resistance will be 71% smaller.

You can continue to do this until radiation resistance becomes the
predominant loss.

Download program SOLNOID2 for coil design and to study these effects.
--
=======================
Regards from Reg, G4FGQ
For Free Radio Design Software
go to http://www.g4fgq.com
=======================


"Art Unwin KB9MZ" wrote in message
...
Richard Clark wrote in message
. ..
On 12 Oct 2003 03:24:10 GMT, oSaddam (Yuri Blanarovich)
wrote:

Art Unwin, KB9MZ wrote:
"The markings are 3600 - 5000 KC."
It was used in a radio or transmitter operating in that range.
(German
WW II
SK10?)

Yuri

Hi Yuri,

More probable is Marine DF.

73's
Richard Clark, KB7QHC

After digging into this subject so that I fully understand it I found
that this particular antenna did not work as it should have done. This
'dummy' assumed that I could obtain any Q that I wanted, however
actual inductor was very inefficient for top band use ( very
broadbanded because of losses.)
I went from 4 inch diameter inductance windings to
a 12 inch o/a diameter with 0.6, O.D. copper tubing for a total length
for the inductor of 35 inches. My intention is to now flatten the
copper tubing so the edges to provide minimum interwinding
capacitance.
However I do want the maximum Q available so the antenna is narrow
banded and inductance change is made by lessening the inductance
length for moving around the band.( or possibly the insertion of a
brass rod)

What other options do I have for increasing Q other than silver
plating of the copper?
I opted away from LITZ wire as I figured that top band was too
high a frequency to benefit from its properties.
Any comments or discussion of the subject would be very apreciated
Best regards
Art