Re: Waves

[Mark Sylvester <msylvest@SPIN.IT>]

At the time I guess I did, but since I learnt about culvert whistlers I've
become more cautious about what is or isn't the result of diffusion. Bill
Beaty is suggesting, as I understand, that the main pulse is transverse,
while the singing is the longitudinal pulse smeared out by the
whistler/waveguide effect, which requires a cable of non-negligible
thickness. This one was probably 3 or 4 cm thick. The singing sound was a
bit like what you hear from the rails when you stand near the track as a
train approaches.

Mark

At 07:19 PM 7/3/00 -0500, Ludwik Kowalski wrote:
> I remember doing the same thing near Arcs, France. But
> I missed the HF. Do you think it was the signature of
> dispersion?
>
> Mark wrote:
> > A few years ago I was hiking in the Alps. At a refuge
> > where we spent the night there was a very long steel
> > cable for hauling goods up from the valley. It was a
> > single span, goodness knows how long. I couldn't resist
> > whacking it with a piece of firewood from a stack nearby.
> > The pulse came back from the valley after what seemed
> > like a very long time. The interesting part is that for
> > a few seconds before the main pulse arrived the cable
> > sang with high frequency noise.