rjr@mgweed.UUCP (Bob Roehrig) (09/17/85)
qst de k9eui hr propagation forecast bulletin nr 37 from arrl headquarters newington ct september 16, 1985 to all radio amateurs bt after more than a month with almost no sunspot activity, a small but plainly visible spot appeared near the east limb of the sun september 13. the solar flux had been down to 68 september 11 and 12, but it rose to 70 and held there for the next few days. even this small flux rise affected propagation noticeably. the 21 mhz band was active over much of the world, and 24 and 28 mhz were open to south and central america daily. the solar flux average for the first half of september was just over 70, and most of the period was below corresponding days of the previous solar rotation. it is likely that we will see somewhat higher numbers after september 20, but no major change is expected. higher geomagnetic activity will make for erratic propagation through the balance of september. the best advice for anyone trying to work out on 21, 24 or 28 mhz is to keep at it. the 5, 10, 15 and 20 mhz signals of wwv, wwvh, and other worldwide time and frequency stations often give good indications of the dx potential of amateur bands near these frequencies. though solar activity is very low currently, and it has been for more than a month, this does not necessarily indicate an early end for cycle 21. lows so far have not been as deep or as long as those recorded in the final months of cycles 18, 19 and 20. american sunspot numbers for september 5 to 11 were between 0 and 2 with a mean of 0.3 ar