LF/MF
Put it another way. Antennas carrying high Voltages are not meant to be
dangling over house roofs, what about your adjacent neighbours houses when
they go on fire. You ought to tell them what is going on
de G3KEV
----- Original Message -----
From: "g4gvw" <[email protected]>
To: <[email protected]>
Sent: Thursday, January 27, 2011 6:40 PM
Subject: Re: LF: Re: Advisory / Warning
> It, also, raises an interesting point about the merits and demerits of
> routing mains cabling in metal conduits (earthed/grounded). On the one
> hand you have a shielded system which, assuming the drop to the house is
> SWA leaves only minor parts to radiate or pick up interfering sigs. The
> downside of course being the grounded metal framework.................
>
> Food for thought and discussion perhaps?
>
> 73
>
>
> On Thu, 2011-01-27 at 15:29 +0000, Hugh_m0wye wrote:
> > 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" <[email protected]>
> > To: <[email protected]>
> > 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
> > >
> >
> >
> --
> 73 es gd dx de pat g4gvw
> qth nr felixstowe uk
> (east coast, county of suffolk)
>
>
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