Topband: RE: skewed paths

Bill Tippett btippett@alum.mit.edu
Mon, 17 Sep 2001 21:10:20 +0100


NM7M wrote:

>There, in my view, scattering plays a major role,
making short-path signals look like signals from a "long-path"
direction.
        
        Bob, please help me with the following quesiton:

If the sunset station (A61AJ for example) transmits to the SE and the
sunrise station (N7UA for example) transmits to the SW, is that not
a "long path" which is opposite to the short path (which is NW from
A61AJ and NE from N7UA)?  

        I'm really very confused as to what you mean by "making short-
path signals look like signals from a 'long-path' direction".  You must be 
saying the signal is short-path from A61AJ to somewhere south of Australia
then backscattered short-path back to N7UA?  You must mean 2 "short-path"
segments to the backscattering area...but the net effect is a long path and 
definitely not short path (Great Circle) which is in daylight...is it not?

        For those interested, here are the reports by A61AJ in November:
http://lists.contesting.com/pipermail/topband/2000-November/001490.html
http://lists.contesting.com/pipermail/topband/2000-November/001542.html

and by N7UA:
http://lists.contesting.com/pipermail/topband/2000-November/001492.html
http://lists.contesting.com/pipermail/topband/2000-November/001541.html

A61AJ (op K1ZM) wrote:
WE GOT A  **GREAT**  PROPAGATION BEARING TEST THIS MORNING WITH BOTH 4 
SQUARES.

TWICE N7UA XMITTED AS FOLLOWS TO ME:

SW SW SW SW (I HRD BOB BEST WHEN HE AIMED THIS WAY)
NW NW NW NW (DOWN 3 DB OR MORE)
NE NE NE NE (DOWN 15DB OR MORE)
SE SE SE SE (DOWN 15DB OR MORE)

I CLEARLY HEARD BOB BEST WHEN HE WAS SW SW SW SW.

THEN I XMITTED TO HIM AS FOLLOWS:

SE SE SE SE (BOB HEARD ME BEST THIS WAY)

SW SW SW SW

NW NW NW NW

NE NE NE NE

THEN BACK TO SE SE SE AGAIN.

BOB CAN ADVISE THE RELATIVE SIGNAL LEVELS BUT HE HAD ME BEST AT 589 WHEN I 
AIMED OUR 4SQ ON THE SE PATH FROM HERE TOWARD HIM.

(N7UA's comments are above which confirm the SW path from his side).  

        If it looks like a duck, and sounds like a duck, maybe it is a duck.

                                                      73,  Bill  W4ZV

P.S.  I don't subscribe to QEX and therefore missed Bob's article in
the November 2000 issue.  Maybe someone who subscribes will forward me
their copy and I'll be happy to return it and reimburse the postage.