TopBand: Re: 160 LP (fwd)
Fri, 05 Feb 1999 07:36:14 -0500 (EST)
>I then set up GEOCLK at the exact time/date of the QSO to get an idea of
>what the terminator looked like. Propagation could've occurred on either
>short path or long path, following the "gray line" either way. Based on
>Larry's use of his SW Beverage to hear A45XR, there's no doubt in my mind
>that the QSO was via long path. If the LP beam headings were more to the
>south, then we run into the daylight problems that Bob suggests.
Absolutely correct Earl! IMHO RF signals follow the path of least
resistance...not necessarily the exact 180 degree long path bearing. This
is why those of us who operate on 40, 80 and 160 know that the "long path"
bearing to EU and AS is usually around 210 degrees at our sunrise and 150
degrees at our sunset, independent of the true great circle bearing. Why?
Because signals duct along the terminator which touches the edge of the
all-daylight area over Antarctica. This is not the first time that Bob has
questioned such paths but I've personally got thousands of LP QSO's on 40
and 80 that say otherwise (and no, my Beverages don't work backwards!) With
all the experience N7DD has on 40, I'm sure he is very well aware of this
path, as are most low band DXers. I believe 160 LP follows the same
propagation mechanism but is more rare.
Actually, it may not be as rare as I once thought based on the
regularity with which XZ1N came in at 210 degrees before my sunrise.
Unfortunately they did not have any RX antennas toward 150 degrees which
was the reciprocal path on their end after their sunset.
The next chance we on the East Coast will have to observe this
will probably be the VK9XX and VK9YY expedition. I remember hearing VK9CR
on Cocos 579 around 2315 UTC via long path about 4 years ago but could not
figure out where they were listening! With a good station and knowledgeable
operators, I expect the VK9 boys will make some LP QSO's this time, both
during our morning and evening openings.
73, Bill W4ZV
P.S. The band sounded great this morning...let's hope it holds for VK9XX!
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