On Sat, 20 Mar 2010, Paul Nicholson wrote:
> Here I mean that amateurs might be able to find a way to
> cooperate with researchers to do something useful.

OK. I had misunderstand you. Certanly it will be good if amateurs
cooperate with researchers. It seems to me vlf (or may be lf at least) is
the only area where HAM's experiments can have some reseach sence. By
the way spectral broading of a signal (if there is no modulation)
obviously connected with  some kind of moution in ionosphere. Such
observations may have some research sence. But i am not familar with this
area. 

I wonder why researchers in this area don't try to radiate coherent 
signal? Signal formed by ourself seems to be more convinient for research
then natural spark signal. I see some analogy with research of light
scattered by some substance. Such experiments can be provided with natural
(but not thermal) incident light. But nobody do that now, everybody use 
laser to simplify analysis followed:-)

> Software would have to de-chirp the triangle for all range
> of delays, 

Yes. Such de-chirping is wellknown in radar science. It is interesting 
idea to use it here.

> is to those involved)?  Perhaps the VLF band should be treated
> by amateurs as a place to do experiments, rather than just
> another band on which to score dx points.

True, true... Now HAMing on HF bacome simple operetion of 'black box' got 
from industry. It is not too interesting. But VLF may bring us someone
more meaningful. 

Regards,
Alexander