Topband: The East Coast Advantage

[Edward Swynar]

On Thursday 29th October, Tom wrote:

"... I read somewhere (ON4UN's book?) that signals can leak from darkness
(night) into daylight (sunset) areas.  However, getting  the angle right
from the daylight area to ENTER darkness is a problem, as well as the
additional attenuation.  Bottom line being - you can hear stuff  arriving
from the dark, but will have a tough time sending signals back..."

**********************************

Hi Tom,

I think having a "DX Edge" gray line slide rule in front of you---before
even turning the rig on---is probably one of the best ways to try & get a
handle on this situation...it sure helped me to "...understand" (and I do
use the term loosely!) a lot, I think, during my DX'ing days on 40-meters.

Specifically, during the winter I could hear---and work---European stations
up to 2+ hours before local sunset here, with my kilowatt and 3-element
inverted Bobtail array. Looking at my "DX Edge", it was evident that the
gray line at that time was out somewhere in the Atlantic Ocean, just east of
Newfoundland.

That would put the area of "useable / reflective" ionosphere some 1250 miles
away from me---and 1250 miles is half the maximum skip distance of a
"...very-low-angle-radiated" signal.

Therefore, I concluded that some component of my signal had to have been
radiated at this "ideal" angle (zero degrees...?), travelled up through
daylight to space unattenuated, then reflected / refracted back down to
earth at the leading edge of the "active" ionosphere (edge of night), 1250
miles away. From there, the signal took the path of "usual" darkness,
behaving in the "usual" way...

Ditto the signals reaching me from Europe, i.e the last "hop" in the
ionosphere was at this same edge of night, and the final leg of this final
bounce continued on to me for the 1250 miles remaining in the hop.

What's interesting about this whole thing is the added spin that can be
considered if one subscribes to Yuri's (ex-VE3BMV) compelling theory of
radio waves being "bent" & directed on high, much as light is bent in fibre
optics: in that instance, my signal to Europe would (I guess) enter the
"fibre optic" propagation "cable" at its open leading edge (the edge of
night), unattentuated, and would continue on its journey to Europe through
it...similarly, signals from Europe would exit the open end of this "fibre
optic" propagation "cable" (again, the edge of night), and be received at my
station...

It's all most interesting...!

I wonder if one day we'll ever really & truly be able to nail any of this
stuff down pat as being "factual", or whether we'll forever debate the
merits of one theory, versus another...

~73~ de Eddy VE3CUI - VE3XZ