On Wed, 17 Mar 2010, Paul Nicholson wrote:
> 
> thing and the exponential factor.  And it is working - it is
> giving the right answer for Stefan's signal!

It is one point yet. Let's wait for 3-4 at least. 

> Yes too.  The ionosphere boundary is more complicated.  There are
> two values for the refractive index - attenuation depends on
> direction relative to Earth's magnetic field.  The result is
> phase and polarisation changes.   

True, true. I am familar with such problems but mainly in condensed matter
(particulary magneto-optics) not in plasma physics. But electrodynamics
itself is the same anyway. 

I have some references to follow
> up here too.   But it is complicated and time consuming.  It
> would be nice to just use average figures for day and night
> attenuation - surely good enough for 'amateur' work.

Certanly empirical value you post is enough for practic calculations. I
have not know this value before. Besides i like to find very
approximative but simple theoretical estimations for different physical
values. Such a play:-) But boundary conditions on D-layer  and exponential
factor then seems to be too complicated for simple estimations. May be
some ideas will come in future.

Regards,
Alexander