Message-ID: <DC91D7EF611642ADA1E361BF55CFCFC8@gnat>
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <570A7631.5050001@lineone.net>
Date: Sun, 10 Apr 2016 17:04:03 +0100
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Subject: LF: Re: Screening an LF Loading Coil
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Status: O

Hi Hugh I think the rule of thumb (or at least the one I use) is that the 
lowest turn should be at least half the coil diamter from the screen base 
(which if too close will exhibit the properties of a shorted turn) and the 
diameter of the screen should be at least twice the diameter of the 
coil....more is better, but.......

I think that should be OK with your coil size supported in the middle of the 
keg, Hope you had the pleasure of emptying it :-))

Alan
G3NYK

----- Original Message ----- 
From: "LineOne" <dhchurch@lineone.net>
To: <rsgb_lf_group@blacksheep.org>
Sent: Sunday, April 10, 2016 4:50 PM
Subject: LF: Screening an LF Loading Coil


>A few years ago I found an aluminium beer keg which had been used for 
>mixing cement. As it was damaged it was no good returning it to the brewery 
>so I have just moved my LF loading coil into it and placed the assembly 
>outside on a corrugated steel roof. (Having the coil suspended from the 
>shack ceiling was not a good idea for the long term).
>
> I took the end off the keg, which is 370mm internal diameter, and the coil 
> is on a 130 mm former, likely to be no more than 160mm diameter wound. The 
> antenna is predominantly current fed so no voltage larger than about 3kV 
> is present.
>
> Has anyone tried this and am I likely to lose radiated power by reducing 
> the Q of the coil, the Tx output voltage and current are just the same?
>
> Hugh, M0DSZ
>