Message-ID: <D7179B21BB8A45989B7891644F3680D1@Hugh>
From: "Hugh_m0wye" <m0wye@radiouk.com>
To: <rsgb_lf_group@blacksheep.org>
References: <AANLkTinbxcRAqcrTiYYLVv2qm1N4BRiaTscLACth_ao8@mail.gmail.com>
Date: Thu, 27 Jan 2011 15:29:52 -0000
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Subject: LF: Re: Advisory / Warning
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If you had a few spare fluorescent tubes lying around you probably wouldn't 
have needed the torch - I understand Nicola Tesla illuminated his workshop 
in this way :-)
73
Hugh M0WYE

----- Original Message ----- 
From: "Andy Talbot" <andy.g4jnt@gmail.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, January 27, 2011 3:06 PM
Subject: LF: Advisory / Warning


> Thought I'd better warn QRO LF ops about this - something that had never
> occured to me before, and could be nasty.
>
> I'm laying floor panels in my loft space, and this involves rerouting some
> of the upstairs lighting wiring - drilling holes and feeding the wire 
> though
> rather than it laying on top of joists where the flooring will sit. 
> Anyway,
> there I was, was happily threading twin-and-earth cable by torchlight (*)
> when I suddenly got a nasty RF burn holding one end of a piece
>
> The 500kHz WSPR beacon is running, and the bit I was holding was isolated
> from the house main earth wire.  The Tee antena runs outside over the
> roof, only 3m or so away from where I was working.   So more than enough
> pickup with me and a bit of wire forming a dipole in the near field of 4kV
> at 500kHz
>
> Now, bearing in mind the burnt ATU cabin of a few months ago, it made me
> think...
> Large bits of bare isolated wire or metal in roof spaces where LF antennas
> pass over could be risky.   They could pick up enough voltage to spark - 
> and
> if there's paper/ wood / plastic at the sparking point, an RF spark that
> always seems to turn into an arc, is very hot.
>
> Just a thought.
>
> (*) and BTW, there is a very strong argument for *not* having your 
> roofspace
> light on the same circuit as your normal upstaris lighting
>
> Andy
> www.g4jnt.com
>