rjr@mgweed.UUCP (Bob Roehrig) (04/10/84)
qst de k9eui hr propagation forecast bulletin nr 15 from arrl headquarters newington ct april 8, 1984 to all radio amateurs bt sunspot numbers and the solar flux have been falling steadily since the end of march. the visible portion of the sun was almost devoid of spots at bulletin time. the solar flux was down to 101, and it is expected to drop further in the next few days. these conditions will make for lower f layer muf than would normally occur at this season. seasonal and solar effects will be most noticeable on 21 and 28 mhz. skip will be poorer on all frequencies, and the number of useable hours per day will go down. the good side of this picture is that, with a quieter sun, the quality and strength of signals will improve, though the useful day is shorter. geomagnetic activity was above normal much of the time recently, and conditions tended to be below normal on all frequencies. we are also moving into the season for sporadic e propagation, which enlivens the 28 and 50 mhz bands at this time of year. characteristics to be expected are very high signal levels at times, but with frequent changes in skip distance and direction. there have been phenomenal e skip sessions on 50 mhz, and linkages of this mode with the seasonal transequatorial propagation have provided exciting 50 mhz dx. in the southern part of the country, 50 mhz was active nearly every day since the middle of march. on april 5 and 6 new zealand, australia and several small pacific islands were worked on 50 mhz from most u.s. call areas. obviously, the transequatorial mode does not require high solar flux levels. watch for it in the afternoon hours on days when the wwv k index is 3 or higher. american sunspot numbers for march 29 through april 4 were between 63 and 118 with a mean of 89.1 ar
rjr@mgweed.UUCP (Bob Roehrig) (04/17/85)
qst de k9eui hr propagation forecast bulletin nr 15 from arrl headquarters newington ct april 14, 1985 to all radio amateurs bt in the first two weeks of april the solar flux was never above 73, and in 9 days ending april 14, there were five 70s and four 69s. this is about as close to quiet sun conditions ay we are likely to see in the next two years. if you were active on the dx bands last week you got a fair sampling of what propagation will be like much of the time through this spring and early summer. strong signals from europe and on other high latitude circuits will be missing on 28 mhz and rare on 21 mhz. propagation north south, and on other transequatorial circuits, will be less effected. our southern states get the best break on this, but all areas will experience it to some extent. at the writers home in florida stations in central africa and the south pacific are heard every few days on 28 mhz. the south american path works just about every day. this is quite different from our conneticut experience, though the same areas are heard now and then up there, and south americans are fairly consistent. with the coming of the sporadic e season, peaking in june and july, the possibility of working across the atlantic on 28, even 50 mhz should not be ruled out. there will be many hours of strong signals over distances of about 500 to 1200 miles on both bands. the e layer effect will show up as very short skip on 20 and 14 mhz. for the forecast week, some slight rise in the solar flux is expected. this will make 14 and 21 mhz sound better, but major openings are unlikely on 28 mhz. two days of good conditions, as far as absorbtion and selective fading are concerned, were coming to an end as this was being written sunday night. the disturbance will be intermittent through the 16th, and there will be more at the end of the week, but no serious (garble) is expected. the area of the sun responsible for the solar flux of 80 on march 24 will be back late this week. there should be some of its life left on this time around, so the muf will be a bit higher by next weekend. american sunspot numbers for april 4 to 10 were between 18 and (??) with a mean of 9 ar