Hi Dave that may be it he talks in it about bubbles formed over mountains
....due to updraughts??shadowing on the western side??.... doing tests on a
55kHz signal from Dixon Ca.  I seem to remember. There is something about
iono chemistry buried in there too. When I first emailed him he said...."Ah
at least one person read it !!" " I though I was writing that for myself"

Nice chap Bob, a professional at one of the Western Universities ....he had
been very ill over the last couple of years but continued to take an
interest in propagation. He died early this year I think. Carl K9LA (and
Vicky), who attended the Convention as the ARRL reps, was a good friend.

Alan

----- Original Message ----- 
From: "Dave Sergeant" <[email protected]>
To: <[email protected]>
Sent: Thursday, July 08, 2010 12:12 PM
Subject: LF: Re: QRN


> On 8 Jul 2010 at 12:00, Alan Melia wrote:
>
> > See a QST article by the late Bob Brown NM6M around 2000 (I can't find
> > the reference) which describes the illumination at the dawn edge of the
> > ionosphere from underneath which creates an intensely absorbing
> > condition. As the intensity increases with solar elevation and the
> > illumination is from above the attenuation actually decrease
>
> You mean:
>
> Bubbles in the Ozone Layer - Bob Brown NM7M (not NM6M)
> QST December 1999 p44-46
>
> Have just downloaded it from the ARRL Members Only Archive
> http://p1k.arrl.org/pubs_archive/97434
>
> 73 Dave G3YMC
>
> http://www.davesergeant.com
>
>