June 1995 Forecast -- Flux Range 70 - 86

by Roy, AD5Q - Houston, Texas

Solar fluxes have hit rock bottom. For now, they won't stay there for long. The actual bottom of this cycle is expected next May (NOAA), when the numbers will be dragging bottom most of the time. Conditions during the WPX CW were slightly disturbed with no spots. In the '94 WPX, the flux numbers were only a few points higher with QUIET conditions the first day and an AWFUL geostorm on the second. I did the contest on 20 again this year. Nightpath conditions were much better last year. Daypath conditions were good this year, but after a full weekend of listening to the East Coast run Europe, I better understand my preference for nightpaths: the skip is longer. Daypath openings on 20 give the East Coast the same degree of advantage in contests that they enjoy on all the other bands. So who said life was fair?

In late spring and summer, nighttime MUF's are at their highest. Meanwhile, summer sun is spreading out the ionosphere and lowering the daytime MUF. This daytime phenomenon doesn't seem to have a proper name. Beginning in my formative years as a DXer, my geek free approach to the seasonal effects on propagation assumed this was some form of "absorbtion" because signals across well known daylight paths just stop propagating. Daylight means higher MUF, right? Not in summertime. For a technical explanation, lets quote W6EL:

The reason winter F2 MUFs are higher than in summer, despite the solar zenith angle being larger, is that the recombination rate is higher in summer as a result of an increase in the molecular-to-atomic composition of the neutral atmosphere. (Sheldon, W6EL)

As the day vs night MUFs approach each other, opportunities arise along long haul DX paths that span both day and night. At sunspot peaks, this brings us spectacular conditions on 15 Meters in late spring with access to Europe most of the day AND night. Currently, 20 is closing around midnight and we are not getting the full nightpath. The window is still broad, as the daypath opening continues into the European evening. We also get openings to Asia for much of the day and into OUR evening. Because of the high daytime noise levels on 20, stations on the dark end of the path will be able to hear MUCH better. QSOs occur only when both stations can copy.

The morning greyline aligns itself to the Far East during the summer, bringing opportunities for many nice 20 Meter Asian contacts until around noon. The greyline also provides us with a pipeline to Russia in the late afternoon / early evening. We hope these paths will be good this year. 40 is still quite usable for nightpath work, though the span of darkness is much shorter and noise levels are high. 40 never really leaves us with no DX.

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