rjr@mgweed.UUCP (Bob Roehrig) (06/06/84)
qst de k9eui hr propagation forecast bulletin nr 23 from arrl headquarters newington ct june 4, 1984 to all radio amateurs bt the solar flux average for may was 129.4, but flux values have been falling since may 21 and the reading for june 2 was 107. in late april we had readings as high as 183, a high for the past 17 months. such peaks have kept the daily average for 1984 at around 127. this is nearly two points above the early 1983 average, despite the fact that cycle 21 is now nearly eight years old. solar flux values during the past week, 120 to 107, are more like what is expected this late in the cycle, but flux levels are not a major propagation factor during the northern hemisphere summer. of more interest at this season is the activity of the earths magnetic field, which will be lower early in the forecast week, making for generally better conditions on all hf bands. it will rise again june 5 to 7, resulting in poorer high latitude propagation until about june 8. sporadic e layer ionization will continue to provide short skip on 28 and 50 mhz, and the chances for 144 mhz will improve. american sunspot numbers for may 24 through 30 were between 59 and 83 with a mean of 72.1 ar
rjr@mgweed.UUCP (06/12/85)
qst de k9eui hr propagation forecast bulletin nr 23 from arrl headquarters newington ct june 9, 1985 to all radio amateurs bt the solar flux numbers for may 30 through june 9 were almost identical to those for may 2 through 12. telescopic observation of the sun also showed very similar sunspot activity to that seen four weeks earlier. this is of interest because active areas have not lasted that long in recent months. if this trend continues we should see flux values in the 80s and 90s through about june 20, with a return to lower numbers later in the month. the practical effects of the higher solar activity vary with the frequencies used. shorter skip can be expected on our lower bands and the dx potential of 14, 21 and 28 mhz will improve somewhat over that observed with the flux in the high 60s and low 70s earlier this year. the influence of higher flux and sunspot numbers is muted in the summer months however, as sporadic e layer ionization reaches its peak in late june. e skip becomes the dominant mode on 21, 28 and 50 mhz for the next few weeks and the effects are not directly related to sunspot numbers or the solar flux. they peak in late june, taper off in july, and disappear almost completely after early august, when the f layer takes over again for the fall and winter months. as to current conditions, a long period of near quiet magnetic field ended with a geomagnetic storm june 7 to 9. the k index was rising again sunday evening, and a major aurora enlivened the closing hours of the arrl june vhf contest, around 2300 utc on june 9th. american sunspot numbers for may 30 through june 5 were between 0 and 27 with a mean of 9.6 ar