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Re: LF: Re: Re: Loading coils and shorted turns

To: [email protected]
Subject: Re: LF: Re: Re: Loading coils and shorted turns
From: "Rik Strobbe" <[email protected]>
Date: Wed, 24 Oct 2001 08:38:41
In-reply-to: <[email protected]>
References: <Chameleon.1003833151.Girardi@tlvk7v>
Reply-to: [email protected]
Sender: <[email protected]>
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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