Topband: Paths between FT5X and North America

[W2RU - Bud Hippisley]

At 11:49 2005-03-29, Bill Tippett, W4ZV, wrote:
>         One more thought about this.  From K7CA's Cedar City QTH,
>the direct bearing to FT5XO is ~190 degrees.  Could this
>mean his QSO was actually long path?

Oh, I definitely think so.  After all, near the antipode, long and short paths are nearly the same length, so the added mileage tranversed by a "long path" ray imparts very little added penalty.  Of far more importance, at 0142Z the "short" path (~190) has been in sunlight for nearly 12 hours, while the "long" path is nearing the end of a full night's worth of darkness, hence MUF and absorption along it should be low, etc.

For this particular date and time and pair of stations, the grayline was coincident with the mathematical long and short paths between the two of them.  (That's why I said "Think 'all K7CA's stars are in alignment this week....' " in my original posting.)  So everything (statistically, at least, and absent any strange auroral or other propagation that evening) would point to the path heading from K7CA being somewhere around 10 degrees east of north.  It could also have been "skewed" to the east from a pure long path bearing, deeper into the zone of full darkness, dependent on whether or not absorption had continued to decline monotonically through the night.  But again, without any really strange stuff going on, I'd have to put my money on a path very close to the long path grayline because we know from zillions of QSOs in the past that grayline provides signal enhancement much (most?) of the time.

I found it instructive to reset my "Default" location in W6EL Prop by typing in K7CA's latitude and longitude (i.e., take the time to relocate the center of my great circle displays), to more easily visualize what the short path and long path to FT5XO and the grayline all look like at 0142Z from Cedar City, Utah when displaying the great circle map.  It's also enlightening, to say the least, to similarly place the Default at Kerguelen and see how North America spreads out around the periphery of the globe.    

Bud, W2RU