rjr@mgweed.UUCP (Bob Roehrig) (09/05/84)
qst de k9eui hr propagation forecast bulletin nr 36 from arrl headquarters newington ct september 3, 1984 to all radio amateurs bt the solar flux average for august was 83.7, the lowest monthly figure since july 1977, when the current solar cycle was just one year old. the flux has been rising slowly since its low of 74 during the third week of august. it appeared to level off at 92 in the first two days of september, but it may move a bit higher before falling again toward the end of the forecast week. after nearly a week of minor geomagnetic disturbances and fair to poor propagation, conditions will improve september 3 and 4. another disturbance is likely september 5 and 6. somewhat more stable propagation is expected september 7 to 10. signs of rising muf are showing, as a result of the more favorable sun position for the northern hemisphere. the 21 mhz band is becoming marginally usefull, mostly on low latitude circuits. more improved 21 mhz coverage will come later in the month. the 28 mhz band should be opening at least briefly by the middle of september, on days when the k index is 2 or lower and the solar flux is above 80. both bands will improve over the next ten weeks, peaking in november. skip will be longer, especially on 40 and 80 meters, than we have seen over the last five years. american sunspot numbers for august 23 to 29 were between 13 and 49 with a mean of 36.3 ar
rjr@mgweed.UUCP (Bob Roehrig) (09/11/85)
qst de k9eui hr arrl propagation forecast bulletin nr 36 from arrl headquarters newington ct september 8, 1985 to all radio amateurs bt (((((accuracy not guaranteed due to poor conditions))))) the almost total solar calm that (started) nearly a month ago is still with us. the solar flux has been no higher than 72 since september 1, and it was down to 69 by the 8th. the flux was even lower 4 weeks ago, so readings in the high 60s are expected through about september 13. the sun is moving to its most favorable position for the northern hemisphere so propagation will tend to be good on 14 mhz and lower bands much of the time. a small flux rise will bring 21 mhz to life, especially when the wwv k index is 2 or lower. even 24 and 28 mhz have been good on the ? days, but thus far they are usable only on transequatorial or other low latitude circuits. flux values in the middle 70s or higher will improve conditions on 24 and 28 mhz quite markedly when the k index is 2 or lower. the k index trend is important so a new value is given every 3 hours. the a index is a 24 hour figure, more useful for statistical purposes. the k index values are expected to be higher during the middle of september but this will tend to be offset by the improving sun position. the qst propagation charts should be more (accurate) this fall. they are now based on solar flux values in the low 70s, more in line with what can be expected in the coming weeks. american sunspot numbers for august 29 through september 5 were between 0 and (3?) with a mean of (.4?). ar