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Message-ID: <3.0.1.16.20011024083841.2d5fce9c@mail.cc.kuleuven.ac.be>
Date: Wed, 24 Oct 2001 08:38:41
To: rsgb_lf_group@blacksheep.org
From: "Rik Strobbe" <rik.strobbe@fys.kuleuven.ac.be>
Subject: Re: LF: Re: Re: Loading coils and shorted turns
In-reply-to: <002301c15be1$27562210$0a00a8c0@ThreeLakes.ca>
References: <Chameleon.1003833151.Girardi@tlvk7v>
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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
>
>
>
>
>