PROPAGATION - by AD5Q HOUSTON, TEXAS -- AUGUST 1996


Though it is still summer and daytime over the pole, equinox time is next month. Days are growing shorter rapidly and the tilt of the greyline at dawn and dusk will shift radically during the next few months. With solar activity as low as it is, this spells an early end to 20 meter nightpath activity. The band is beginning to close earlier, with fewer signals coming through in the late evening. This means the DX windows in the evening will be shorter, and morning openings into areas of the world where it is evening will also be shortened.

Daypath openings are changing and shifting, providing improved access to Europe in the morning. As the transition to lowband season continues to completion, opportunities to work into Europe will move predominantly into the morning hours while the Asian paths will work their way into late afternoon. The direction of morning and evening grey lines will be reversed, so that these pipelines tilt toward Europe in the morning and Asia at dusk. In the meantime, these alignments will be northerly and 20 meter polar paths will remain very workable (though shorter). Europe will become workable for much of the day, especially from the East Coast. In the southern hemisphere conditions will be improving on 20, bringing better opportunities for contacts into Antarctic regions.

August is the last month where daytime MUFs are determined by an overheated and thinned ionosphere, and we can expect rapidly improving daypath propagation as this problem dissipates during September. With solar fluxes so low anyway, we cannot expect much improvement from 15 meters. 20 will become our daypath band at this portion of the cycle, but there is also hope for 17.

Though nighttime MUFs are currently dropping, they are still high enough to keep 40 open through the night. The length of the night is growing longer and more of the densely populated northern hemisphere is becoming accessible. DX activity is already moving to this band, though summer QRN levels remain a problem. Some of the signals coming through on 40 have been quite loud, including many from the former USSR in the early evening. Serious lowband operators are beginning to test the waters on lower frequency bands. We anticipate an early fall, and an excellent lowband season that will last for many months.

http://www.nol.net/~ids/prop.html
E-Mail: ad5q@kb5tes.#setx.tx.usa.na or ids@nol.net