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Message-ID: <000c01cbc00e$4a122790$4001a8c0@lark>
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <DF8D483685124FFBA8436BD2C5850C8E@White> <BLU146-W22AB5AAEB44DDDB72BD06ACFE00@phx.gbl> <4D449E50.2020507@o2.co.uk>
Date: Sat, 29 Jan 2011 23:43:07 -0000
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Subject: LF: Re: LF coil tuning
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Hi Peter I think this is analogous to putting an aluminium or brass slug
into a coil as with the VHF Toko range where there is an optional ferrite of
aluminium.core. I have never measured Qs I suspect it is a bit lossy maybe
that is why a single shorted turn is used for a loading coil.

Alan
G3NYK

----- Original Message ----- 
From: "Peter Dodd" <g3ldo@o2.co.uk>
To: <rsgb_lf_group@blacksheep.org>
Sent: Saturday, January 29, 2011 11:10 PM
Subject: LF: LF coil tuning


> The traditional method of tuning an LF loading coil is to use a
variometer.
>
> I have been investigating methods of tuning coils for mobile use and one
> method that appeared briefly  in one of the ARRL Handbooks of the 50s
> was the shorted turn method of tuning.
>
> I tried a home made coil of 136uH on a 5cm diameter former and using a
> shorted turn of 2mm insulated wire and obtained a tuning range of 32uH.
> (136 - 102uH).
>
> Has anyone out there tried this?
>
> Regards
>
> Peter G3LDO
>
>
>
>
>