TopBand: Re: 160 LP (fwd)

Bill Tippett
Fri, 05 Feb 1999 16:15:18 -0500 (EST)

W1FV wrote:

>Sometimes LP and SP are open simultaneously and on a non-directional
>receiving setup, one can distinctly hear the LP signal as an echo.  This
>happens quite a bit on 40 m around local sunrise and with my Beverage
>antennas it is possible to do quick direction switching and actually
>resolve the LP and SP signals spatially and temporally.  

        I agree fact it is very common on 80 for SE Asian
signals to be coming via long path (210 degrees) before sunrise and
then swing to short path (330 degrees) at and after sunrise.  In fact,
I even observed this one morning on XZ1N who was first peaking at 210
degrees about 30 minutes before my sunrise, and then the signal swung
to 335 degrees as sunrise approached.  

        I think the point that Bob and the software programs miss is
that signals do not propagate in straight lines just as they do not
"reflect" from the ionosphere.  Instead they follow the path of least
resistance which often is along the terminator at both ends of the 
path.  On 80 meters from Colorado, I worked stations from Denmark to
Hong Kong and everywhere in between via the 210 degree path at sunrise.
It was amazingly constant independent of the great circle bearing of the
DX station.  The only exception was the Indidan Ocean (FR, 3B9, etc.)
which was a true great circle long path bearing at 260 degrees.  I think
this latter path is similar to the path that NE stations have to VK6 at
their sunset on 160 and is much more common than the sunrise and sunset
long paths to Asia.

        The point you mention about "skewing" is a different phenomena
in my opinion.  It is usually caused by an active geomagnetic field
which causes northern hemisphere signals to skew away from magnetic north.
Although I never saw Japan skew to the south from Colorado (since magnetic
north from there was 12 degrees and JA was 315 degrees), I have often seen
cases here on the East Coast where EU skews south during magnetic storms.
Usually it skews less than 90 degrees which is not the same as true long
path (always greater than 90 degrees.)

        To gather some actual data on long paths, I would like all to
send me their QSO data for what they think are long path contacts on 160.
Please include the following info (as I indicated for myself):

Call       Date       Time       Bearing        Your QTH

UA9UCO z18 29SEP87    1232         210          Colorado
JJ1VKL/4S7 28DEC91    1335         210          Colorado
VK9CR      15FEB96    2315         150          NC 579 SWL only
9V1XQ      12JAN96    2309         150          NC 589!
S21XX       4FEB97    2320         150          NC
XZ1N       28NOV98    2230         150          NC SWL only
XZ1N   Early DEC98    1130         210          NC SWL many times!
YC0LOW       Dec?     2230?        210          NC SWL (Did not log it)

I will be leaving for HC8 for sightseeing and the ARRL CW next week
but will compile this info and send a copy to anyone interested after
I return.  Note that I have not included contacts with 9M2AX and VK9XY
at my sunset which were coming via a skew path over Europe.  I have
always been mystified that these signals come over Europe one day and
South America the next.  Anyone who can figure that one out please let
me know!  

                                                73,  Bill


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