rjr@mgweed.UUCP (Bob Roehrig) (02/26/85)
qst de k9eui hr propagation forecast bulletin nr 8 from arrl headquarters newington ct february 24, 1985 to all radio amateurs bt the solar flux reached its february high, 78, on the 19th. it then dropped back steadily, to the months low, 72, on the 24th. the flux is expected to drop to about 70 by the end of february. a mild rise is likely in the first few days of march. qst prediction charts covering late february and early march continue to be on the optimistic side as to maximum usable frequencies. the february qst charts are based on a solar flux of 89. those in the march issue are based on a flux of 88. experience this winter has confirmed that solar flux numbers in the high seventies or higher are needed if the 21 mhz band is to be useful for dx work on anything but the most favorable north south paths. flux values consistently in the eighties or higher are needed to do the same for 28 mhz. with the current flux readings even 14 mhz is mainly a daytime band. low ionization density generated by such low solar activity will continue to turn our lower frequencies into long skip territory, often hampering their use for reliable communication over distances under a few hundred miles. this is bad for traffic handlers but it helps to spur interest in working for multiband dx awards. american sunspot numbers for february 14 to 20 were between 25 and 0 with a mean of 10.1 ar
wheatley@inuxi.UUCP (Steven Wheatley) (02/25/86)
QST DE K9EUI HR PROPAGATION FORECAST BULLETIN NR 8 FROM ARRL HEADQUARTERS NEWINGTON CT FEBRUARY 24, 1986 TO ALL RADIO AMATEURS BT THE SOLAR FLUX CURVE FOR FEBRUARY IS TAKING ON THE SHAPE OF A SLIGHTLY IRREGULAR SINE WAVE. FROM 84 ON FEBRUARY 1 IT RISES QUICKLY TO 99 ON THE 3RD, PEAKS AT 103 ON THE 5TH, SLIDES TO 95 BY THE 9TH, AND TUMBLES DOWN TO 70 ON THE 17TH. IT HAS BEEN AS LOW AS 67 SINCE, AND AT 69 ON THE 23RD, IT APPEARS READY TO START UPWARD AGAIN. THE ODDS ARE AGAINST THE FLUX REACHING 103 IN EARLY MARCH, AS IT DID IN FEBRUARY. THAT FIGURE WAS THE HIGHEST SINCE JULY 1984, AND WE ARE NOW IN WHAT IS PROBABLY THE LAST FULL YEAR OF CYCLE 21. AN APPRECIABLE RISE SHOULD BE UNDERWAY HOWEVER BEFORE NEXT WEEKS BULLETIN. THE TWO WEEK RUN AT 85 OR HIGHER MADE THE FIRST HALF OF FEBRUARY A VERY INTERESTING TIME ON 21, 24 AND 28 MHZ. NOW THAT WE ARE BACK TO QUIET SUN LEVELS AGAIN, 24 AND 28 MHZ ARE ALMOST DEVOID OF DX, AND 21 MHZ IS ACTIVE MAINLY IN THE LOWER LATITUDES AND ON TRANSEQUATORIAL CIRCUITS. NO MAJOR CHANGE IN THIS PATTERN IS EXPECTED BEFORE ABOUT THE 25TH. EARLY FEBRUARY WAS MARKED BY THE MOST SEVERE GEOMAGNETIC DISTURBANCES IN SEVERAL YEARS. BECAUSE OF THE 28 DAY MONTH, WE CAN EXPECT RECURRENT MAJOR GEOMAGNETIC EFFECTS ON ABOUT THE SAME DATES IN MARCH. THIS TWO MONTH PATTERN IS APPARENT IN PROPAGATION RECORDS FOR FEBRUARY AND MARCH AS FAR BACK AS THE 1930S. VHF ENTHUSIASTS TAKE NOTE THAT THE SECOND WEEKEND OF MARCH SHOULD BE MARKED IN RED ON YOUR OPERATING SCHEDULE. WE WERE IN A DISTURBANCE OF MILDER CATEGORY AS THIS BULLETIN WAS BEING PREPARED. IT SHOULD BE OVER BY THE 26TH. THE LAST 2 DAYS OF FEBRUARY AND THE FIRST FEW OF MARCH SHOULD BE OF SLIGHTLY BETTER THAN AVERAGE PROPAGATION ON ALL DX FREQUENCIES. AMERICAN SUNSPOT NUMBERS FOR FEBRUARY 13 THROUGH 19 WERE BETWEEN 0 AND 20 WITH A MEAN OF 4.9. AR