Re: LF: EbNaut from Todmorden

[David Hine <evad_hine@yahoo.co.uk>]

Hi, It sounds fascinating -the sort of thing I like to do!!! Another motto -transmit and be damned!!!!. BUT if you are on a mains PME system (as most domestic supplies have been since the 1970's), remember the mains 'earth' (and the bonded piping in your house) is actually a direct connection to mains neutral!! This can become extremely dangerous (to you) in the event of any neutral faults or disconnections in the street cables or corroded neutral junctions, as this 'neutral' can become live up to 440v AC, putting you and your equipment in danger as the 'fault' current passes to the outdoor earth!! So take care as the mains 'earth' can then become live  up to 440v as faults can occur without any warning. With PME it is much wiser to isolate from anything outdoors and never use the mains 'earth' and / or house plumbing in conjunction with outdoor earths. It is your choice, so please take care and let me know your transmitting results. Never tamper with or try to 'defeat' a working house safety trip!!! -that could cost you very dearly!!!!!!! With very kind regards, Dave. 

---

From: Paul Nicholson <vlf0403@abelian.org>
To: rsgb_lf_group@blacksheep.org
Sent: Saturday, 19 March 2016, 19:53
Subject: Re: LF: EbNaut from Todmorden

Peter wrote:

> End of World is Nigh ...

A pal at Uni (quite a party animal) often used to say - if
anything's worth doing, it's worth doing to extremes.  I've
often taken that as sound advice.

Stefan wrote:

> It's a big fun, you know. Remember my earth antenna in
> the forst :-)

Indeed yes, and I think I received a little signal from it.

Today I ran out 500m of wire and terminated the remote
end in a convenient bog.  Not the km I was thinking of
but it'll do for a start.

The resistance of the ground loop through the wire and
back to the domestic ground is 380 ohms.  It is virtually
all resistance, I can see a slight phase shift of the test
current but not enough to measure the reactance accurately.
That's a pity.  If I knew the inductance I could estimate
the effective area of the one turn ground loop.  Anyway the
loop impedance is flat up to 2MHz where there is a very
slight peak.

I got the amplifier fired up.  It's quite a beast, rated 5kW
into 4 ohm.  Actually I've got two of these but one will do
for now.  I reckon about a 20 turn primary around that monster
toroid will match a kW or two via the 400t secondary into the
earth loop.

I don't know if I'll get it rigged up tonight but maybe
tomorrow evening I might be able to do a 'large signal
impedance measurement'.

I guess this isn't going to radiate very well but it's
fun to try.  If any of the neighbours ask why the ground
is steaming I'll just tell them about the heavy duty
mole repeller I'm working on.

--
Paul Nicholson
--