Max wrote:

Both long wires running parallel to transmission lines and coils
situated under transformers were used "back in the day."  The power
companies' ability to detect small losses (hundreds of watts on a
line carrying megawatts) has always been much better than the average
person would think.  Well-established law (at least in the US) holds
that it is theft of services, although some folks think it should be otherwise.

I knew several people who lit outbuildings with fluorescent tubes
powered from wires strung in the near field of a 50 kW AM radio
station I once worked for.  The closest farmers had to take
precautions putting up wire fences (limiting the continuous length
and grounding at intervals), without which they could give you a nasty RF burn.

Best regards,

Charles

Max Robinson wrote:

It sounds a bit of a myth to me. I've never done the maths, but I doubt you
could get a lot of power from a wire like this. To power most of his farm
machinery would need many kW.

On the very high power lines, they tend to be location very high, in which case
I would have thought the fields should cancel at long distances, as there will
be 3 out of phase currents.

I think for lighting, you might be able to claim you did it to reduce the
E-field at your house, as you were worried by the health effects. Sine you need
to dump the power somewhere, a light bulb seemed the cheapest dummy load. A 100
W light bulb is a lot cheaper than a 100 W resistor!

On a similar note, I heard about someone who powered his greenhouse by using the
small voltage between neutral and earth that will exist. I know there is at
least 30 mA available at my house, as shorting neutral to earth will trip a 30
mA RCD. But I measured the voltage once, and whilst I can't recall what it was,
it was less than 1 Volt.

Dave

Not wishing to push this O/T thread more O/T but coming from England,
and now in New Zealand, we have these sodium streetlights which I
think are a pain in the neck. They have only two narrow spectra of
yellow light and although they produce light it makes it hard, if not
impossible, to make out colours. I wonder if they are being used in
other members countries?

Steve

2010/1/31 Dave Martindale dave.martindale@gmail.com:

--
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.

Hi Steve,They do use them in the USA.The advantages are,1 High efficiency2 Better visibility in rain and fog. As there is only one main colour you do not get diffraction rainbows.3 Kind to astronomers. A simple narrow stop band optical filter allows astronomers to remove the light pollution. In some areas around observatories they are mandated by local planning regulations.
These are considered to outweigh the disadvantage of no colour rendition.
Robert G8RPI.  

--- On Sun, 31/1/10, Steve Rooke sar10538@gmail.com wrote:

From: Steve Rooke sar10538@gmail.com
Subject: Re: [time-nuts] [OT] Ikea Lamp
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Date: Sunday, 31 January, 2010, 9:19

Not wishing to push this O/T thread more O/T but coming from England,
and now in New Zealand, we have these sodium streetlights which I
think are a pain in the neck. They have only two narrow spectra of
yellow light and although they produce light it makes it hard, if not
impossible, to make out colours. I wonder if they are being used in
other members countries?

Steve

2010/1/31 Dave Martindale dave.martindale@gmail.com:

--
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

In France, it is known as "fleur de souffre", which translates litterally to
"flower of sulphur". In French, there is no confusion possible between the
terms flower (fleur) and flour (farine).

Didier

In my 1963 EH Sargent and Company catalog, they list:

Sulfur, USP, Precipitated Powder
Sulfur, NF Sublimed Powder
Sulfur, Sublimed Flowers (Tech)
Sulfur, Lump (Roll)

And something about Seconds, NIST Grade...

-Chuck Harris

Don Latham wrote:

Steve Rooke wrote:

Sweden has them. It's the classical sodium D1 and D2 lines. Kind of neat
that one can calibrate ones spectrometer by the highway. :)

I think white is becoming more popular now.

Cheers,
Magnus

I believe that it is possible to light a fluorescent tube, at least
dimly, by standing on the ground under a power transmission line
operating at more than 100 kV , holding one end of the tube in your
hand, and sticking the other end up in the air.  I have never done
this, exactly, but I have held a fluorescent tube near a ham antenna
and seen it light, and on the web I have seen photos of people doing
it under electric utility lines.

Of course I have seen fluorescent tubes light near Van de Graaff
generators and Tesla coils.  We all have.  However, such machines
generate E-fields much stronger than you'll find near ground level
under an electric utility line.

I do not believe that one could get a fluorescent tube to light by
holding it near ground level under an 11-kV line.  But this is just my
gut feeling.  I could certainly be wrong.  I have not done the
experiment; nor have I done a calculation of the expected field
strength.

The story of a farmer drawing enough power "to operate most of his
farm buildings" from a wire running under and parallel to a HV line
sounds like an urban legend to me.  As does the story of a "guy that
had a big coil of wire in the roof of his shed and... could light a
100W incandescent bulb from the stray fields."  It's hard to draw
significant power from the field surrounding a power line because a
huge reactance must be tuned out.  If it were easy, then power-
transmission companies would be dissipating substantial and
economically intolerable amounts of power in the ground, which has
non-negligible conductivity.

During my summer working in the engineering department of a Bell
System operating company, I personally observed examples of 60-Hz AC
e.m.f. induced longitudinally in telephone cables running for miles
along rural pole lines, directly under 60-Hz power lines.  It was not
unusual to see an induced e.m.f. of the order of 100 V RMS.  A person
could get a painful shock from this voltage.  However, a human is a
pretty high-resistance load.  You could not draw watts of power from
such a source.  The Thevenin equivalent source impedance was too high.

BTW, it is necessary to distinguish induced e.m.f. from a potential
difference between separated points on the surface of the ground due
to resistance in the ground multiplied by conduction current in
the ground.  Conduction current in the ground arises whenever less
than 100% of the current flowing in a single-phase power line, or the
common-mode current in a three-phase line, does not return through the
neutral wire/cable of the line.  In rural areas where most of the
loads are single-phase, and a three-phase line is tapped for single-
phase loads separated by miles or more, it is not unusual to find very
high ground currents.  I remember observing symptoms of high ground
currents also near electric railroad lines.  As electric locomotive
such as the Pennsylvania RR's GG-1 drew single-phase 25-Hz current
from an overhead wire and returned it through the rails; but a
significant fraction of the return current flowed through the ground,
because the rails were connected to driven "ground" rods, presumably
for safety.  Trolley cars on the streets of Baltimore ran on DC, and
did the same thing.  Some of the ground current would find its way via
safety-ground rods through the neutral wires of the 60-Hz electric
utility.  When this DC flowed through the windings of 60-Hz power
transformers, it partially saturated the transformer cores, causing
waveform distortion, so that 60-Hz harmonics were heard in
neighborhood telephones.

The notion of "ground" as one big equipotential surface, an infinite
sink for charge / current, is a mass delusion.  It's a delusion for DC
and low-frequency AC.  For RF, it is so wrong that words fail me.

-John

I hate the yellow lamps in my area because they are only found in certain vicinities. You're driving along at night, maybe searching for something, and suddenly one of the "street lamps" turns red! It's happened to me a few times...

Dave
----- Original Message -----
From: "Robert Atkinson" <robert8rpi@yahoo.co. uk >
To: "Discussion of precise time and frequency measurement" <time-nuts@ febo .com>
Sent: Sunday, January 31, 2010 4:34:23 AM GMT -07:00 US/Canada Mountain
Subject: Re: [time-nuts] [OT] Ikea Lamp

Hi Steve,They do use them in the USA.The advantages are,1 High efficiency2 Better visibility in rain and fog. As there is only one main colour you do not get diffraction rainbows.3 Kind to astronomers. A simple narrow stop band optical filter allows astronomers to remove the light pollution. In some areas around observatories they are mandated by local planning regulations.
These are considered to outweigh the disadvantage of no colour rendition.
Robert G8RPI.

--- On Sun, 31/1/10, Steve Rooke <sar10538@ gmail .com> wrote:

From: Steve Rooke <sar10538@ gmail .com>
Subject: Re: [time-nuts] [OT] Ikea Lamp
To: "Discussion of precise time and frequency measurement" <time-nuts@ febo .com>
Date: Sunday, 31 January, 2010, 9:19

Not wishing to push this O/T thread more O/T but coming from England,
and now in New Zealand , we have these sodium streetlights which I
think are a pain in the neck. They have only two narrow spectra of
yellow light and although they produce light it makes it hard, if not
impossible, to make out colours. I wonder if they are being used in
other members countries?

Steve

2010/1/31 Dave Martindale < dave . martindale @ gmail .com>:

--
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.

time-nuts mailing list -- time-nuts@ febo .com
To unsubscribe , go to https :// www . febo .com/cgi-bin/mailman/ listinfo /time-nuts
and follow the instructions there.

time-nuts mailing list -- time-nuts@ febo .com
To unsubscribe , go to https :// www . febo .com/cgi-bin/mailman/ listinfo /time-nuts
and follow the instructions there.