Dear J,
On Thu, 20 Jan 2005, J. Allen wrote:
Alex's calculation of my antenna system indicates that a base loading coil
of 700 Ohms is needed.
I was thinking of reducing the solenoid loss by paralleling two or more #17
wires and close-winding them. If I parallel wind three #17 wires will it be
worth the effort in reducing coil loss or does a simple coil with only one
#17 conductor make any sense here?
If You paralleling two or more wires then coil loss will NOT decrease too
much. Moreover in some case loss can increase not decrease. It depend on
coil shape (D/l ratio). It is not too dificult to understand. If You
use two or more wires then coil length increase. This yeld more turns to
achive inductance needed. More turns - more wire length - more loss in
one wire. But certanly two wires in parallel have less resistance. Then
Q-factor will be APROXIMATLY the same. Use two or more wires in parallel
is resonable to optimaze former_diameter/winding_length ratio of a
solenoid ONLY.
Winding with space equal to wire diameter yelds Q-factor beter. But not
too much. Dependence is not strong. Thus You can wind Your coil close.
Moreover Q-factor depend ONLY on wire-diameter/winding-space ratio,
coil-diameter/winding-length ratio, former diameter and DO NOT
depend on wire diameter itself (if wire radius is more then pentation
depth). This conclusion looks very strange of cose. I was very suprised
when I derive such a conclusion theoreticaly few years ago. But few
experiments with some coils ensure me this is true:-) This strange
behaviour of Q-factor is a result of proximity effect.
What is diameter of wire #17 in millimeters? I'll do aproximate estimation
coil with Your formers. Though wire is coper...
73 de RA9MB/Alex
http://www.qsl.net/ra9mb
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