rjr@mgweed.UUCP (Bob Roehrig) (03/20/84)
(Sorry but the end of this transmission was lost) PROPAGATION BULLETIN NR 12 FROM ARRL HEADQUARTERS NEWINGTON CT MARCH 12 1984 TO ALL RADIO AMATEURS THE PARADE OF SUNSPOTS ACROSS THE VISIBLE SURFACE OF THE SUN THAT BROUGHT SOLAR FLUX PEAKS OF 180 ON JAN 29 AND 175 ON FEB 29 MADE ITS THIRD APPEARANCE LAST WEEK. STARTING FROM 100 ON MARCH 10 AND 11, THE SOLAR FLUX WAS UP TO 136 ON MARCH 15. THOUGH ACTIVITY APPEARS LOWER THIS TIME AROUND, FAIRLY HIGH FLUX NUMBERS SHOULD BE WITH US UNTIL THE LAST FEW DAYS OF MARCH. THIS WILL HELP TO OFFSET THE NORMAL SEASONAL DECLINE IN OVERALL DX PROPAGATION EXPECTED IN EARLY SPRING. A GOOD IDEA OF THE EFFECTS OF HIGHER SOLAR FLUX VALUES CAM BE OBTAINED FROM THE PROPAGATION CHARTS IN QST FOR MARCH, PAGE 65. TAKE A HIGH LATITUDE PATH SUCH AS EASTERN USA TO EUROPE. NOTE THAT THE PREDICTED MUF FOR LATE MARCH IS UNDER 26 MHZ. FOR OPTIMUM CONDITIONS AND A SOLAR FLUX OF 108. EVEN ON THE BEST DAYS, THE NORTH ATLANTIC PATH WOULD BE BARELY USEABLE ON 28 MHZ, YET MANY CONTRIES OF EUROPE WERE COMING THROUGH WELL FOR SEVERAL HOURS ON MARCH 18 AS THIS BULLETIN WAS IN PREPARATION. DX CONDITIONS WERE MARKEDLY BETTER ON ALL LOWER DX FREQUENCIES AS WELL.
rjr@mgweed.UUCP (Bob Roehrig) (03/21/84)
QST DE K9EUI HR PROPAGATION FORECAST BULLETIN NR 12 FROM ARRL HEADQUARTERS NEWINGTON CT MARCH 19, 1984 TO ALL RADIO AMATEURS THE PARADE OF SUNSPOTS ACROSS THE VISIBLE SURFACE OF THE SUN THAT BROUGHT SOLAR FLUX PEAKS OF 180 ON JAN 29 AND 175 ON FEB 29 MADE ITS THIRD APPEARANCE LAST WEEK. STARTING FROM 100 ON MARCH 10 AND 11, THE SOLAR FLUX WAS UP TO 136 ON MARCH 15. THOUGH ACTIVITY APPEARS LOWER THIS TIME AROUND, FAIRLY HIGH FLUX NUMBERS SHOULD BE WITH US UNTIL THE LAST FEW DAYS OF MARCH. THIS WILL HELP TO OFFSET THE NORMAL SEASONAL DECLINE IN OVERALL DX PROPAGATION EXPECTED IN EARLY SPRING. A GOOD IDEA OF THE EFFECTS OF HIGHER SOLAR FLUX VALUES CAN BE OBTAINED FROM THE PROPAGATION CHARTS IN QST FOR MARCH, PAGE 65. TAKE A HIGH LATITUDE PATH SUCH AS EASTERN USA TO EUROPE. NOTE THAT THE PREDICTED MUF FOR LATE MARCH IS UNDER 26 MHZ, FOR OPTIMUM CONDITIONS AND A SOLAR FLUX OF 108. EVEN ON THE BEST DAYS, THE NORTH ATLANTIC PATH WOULD BE BARELY USEABLE ON 28 MHZ, YET MANY COUNTRIES OF EUROPE WERE COMING THROUGH WELL FOR SEVERAL HOURS ON MARCH 18 AS THIS BULLETIN WAS IN PREPARATION. DX CONDITIONS WERE MARKEDLY BETTER ON ALL LOWER DX FREQUENCIES AS WELL. ALSO OF INTEREST WAS A REAPPEARANCE OF 50 MHZ DX IN THE PAST WEEK, THOUGH THIS WAS OF THE NORTH SOUTH VARIETY LESS AFFECTED BY LOW FLUX VALUES THAN EAST WEST PATHS. HIGH LATITUDE PROPAGATION WILL BE MOSTLY GOOD, WITH ONLY MINOR INTERRUPTIONS, MARCH 19 THROUGH 23. FROM MARCH 24 THROUGH 31, MORE FREQUENT AND SEVERE GEOMAGNETIC DISTURBANCES WILL DEGRADE HIGH LATITUDE COMMUNICATION, ESPECIALLY AROUND THE 25TH AND 30TH. TRANSEQUATORIAL PATHS WILL NOT BE GREATLY AFFECTED, AND AT 28 AND 50 MHZ THEY MAY BE IMPROVED AS THE DISTURBANCES CLEAR UP. AMERICAN SUNSPOT NUMBERS FOR MARCH 8 THROUGH 14 WERE BETWEEN 45 AND 111 WITH A MEAN OF 68.6.