Hello Larry,
I can confirm that shorting turns does lower the Q (= increase losses). The
effect is miminal when only a few turns are shorted, but when I measured my
loading coil on a commercial impedance analyzer (HP) I noticed following :
- using 50% of the turns, other 50% left open : Q = 350
- using 50% of the turns, other 50% shorted : Q = 220
73, Rik ON7YD
At 12:38 23/10/01 -0400, you wrote:
Claudio wrote.....
P.S.: shorting turns to adjust the inductance of a coil should
not be harmful,
When I was bringing up the Decca here last winter and trying to get power
into the antenna I found that shorting turns had a disasterous effect on the
performance of the loading coil. I learned quickly to leave the unused coil
OPEN at the top, for those with Telco experience, a "bridge tap". When I
quit shorting turns I found the antenna current went up and the radiated
signal also went up.
Just my experience....
Larry
VA3LK
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