On Fri, 24 Oct 2014 04:42:29 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Martin Eastburn fired this volley in
:

That is 1000 times if those are the correct values of 10^11 vs 10^14.
That is a wide band difference.


It doesn't much matter how wide the difference is.

Lacking a tuned tank, any arc (AC or DC or HF modulated) is a "broadband
emitter", radiating RF all the way from SLF (audio) frequencies clear up
to ultra-short wavelength UV. (and maybe beyond).

Some welders have chokes and various tank circuits (generally in the form
of low-pass filters) to help prevent emission through the body of the
unit, but the welding leads always act as antennae.

Of course, any electrical apparatus has "tuning peaks" that tend to
absorb or radiate certain frequencies preferentially over others.
Manufacturers try to make their units suppress radiation in the ranges
where radio communications is done -- with varying degrees of success.

It's generally recommended that people with electrical cardiac or
neurological assistance devices avoid close proximity to arc welders of
any kind.

Lloyd

Lloyd, the radiation from welding arcs is nowhere near "broadband." If
you look at the spectral output charts, they look more like a
fluorescent light from hell. g

Typically, the output falls off to near-nothing at wavelengths longer
than 800 nm, with an occassional spike at lower frequencies but with
almost all of the energy emitted at much higher ones. There's enough
noise at lower frequencies to raise hell with radio receivers, but not
enough to do much of anything else.

I haven't seen a good, big chart of this for a while, but here's a
little one. Scroll about halfway down:

http://www.ehime-iinet.or.jp/ehime_e...bun/ronbun.htm

--
Ed Huntress