On Aug 7, 2012, at 4:14 PM, Nick Hall-Patch wrote:
> I suspect that the Florence location suffered somewhat from being 1000 feet
> inland, Gary and Bill. My limited experience has been that
you're generally
> better off being right at the coast for the best DX, although
Gary's experience
> seems to point to an advantage to being right at the coast and
higher up, and
> that phenomenon certainly needs to be looked at more carefully.
That's almost what I blurted out in my original email -- what Gary
[and others' research to understand it] may have stumbled upon is
the true nature of 'sea gain' or 'coastal effect' and that it falls
off REALLY rapidly away from the coast whether you're at sea level or elevated.
I think it's really hard to 'compare' what Gary's able to hear on a
small portable radio with a super cool FSL antenna with what I do
via a Perseus & DKAZ. Somehow I give him several 'bonus points'
just for doing what he does LIVE, with cars whoosing by and a few
hundred feet above the pounding surf while I'm literally
sleeping! Now that I've been to where Gary did his last DXpedition
I'm VERY impressed. I would not do what he does.
I might visit Sea Lion Caves down the road but I would NOT stand out
there with a portable radio and a FSL and cars whooshing by at
sunrise! For that alone he deserves a '10' on the Olympics scale.
> There was a research paper done years ago by the BBC, I believe,
showing the
> "coastal effect" as a wavefront moved from the water to the land,
and although
> there were peaks in signal strength as one moved inland, their
location depended
> on the frequency of the received signal, were compensated for
by lower signal
> strength in the area between the peaks, and, overall signal
strength dropped the
> further inland one went. I'll look it up again when I'm home; I
have a vague
> recollection that cliffs might have been incidentally involved,
though I don't
> think that clifftop vs. seashore was investigated.
I've seen that paper and know some people who had something to do
with it ... assuming they're still alive. It was incorporated, in
some fashion, into the Rio 1979 Final Acts where the Region 1 & 3 MW
stuff was negotiated/allocated. I remember once writing a TI-59
'program' to calculate desired and undesired signals along radials
using the 'Rio Plan.' Had to see if changes we wanted to make to
VOA MW facilities would affect Rss by more than 0.5 dB -- the limit
to having other admins notified!
Blah, blah, blah ... that's when people still gave a hoot about AM
and HF. :-(
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