SB PROP @ ARL $ARLP016<br />ARLP016 Propagation de K9LA<br /><br />ZCZC AP16<br />QST de W1AW <br />Propagation Forecast Bulletin 16 ARLP016<br />>From Carl Luetzelschwab, K9LA<br />Fort Wayne, IN April 17, 2003<br />To all radio amateurs <br /><br />SB PROP ARL ARLP016<br />ARLP016 Propagation de K9LA<br /><br />Carl Luetzelschwab, K9LA is filling in for Tad Cook, K7RA this week.<br />This report is one day earlier than usual because of Good Friday.<br /><br />Geophysical activity during the period ran the full gamut - from<br />quiet early in the period to some minor to major storminess later in<br />the period. The minor to major storminess was caused by high-speed<br />solar wind that was induced by a coronal hole.<br /><br />Solar activity during the period was low to very low. The largest<br />flare was a C7 event last Friday.<br /><br />For the next several days, geophysical activity is forecasted to<br />decrease to unsettled conditions. Thus propagation should generally<br />improve as the weekend approaches. Additionally, solar activity is<br />forecast to be low for the next several days, so flares shouldn't<br />cause any problems.<br /><br />Your reporter noted many 6-meter spots on PacketCluster early this<br />week. This is a reminder that the summer Es (sporadic E) season is<br />underway, and Es can provide a link to trans-equatorial propagation<br />(TEP) for stateside stations. Jon, N0JK reports southwest, south,<br />and east coast stations working into South America on Monday and<br />Tuesday afternoon and into the evening. Be sure to keep an eye on<br />6-meters, as historical data shows that the 6-meter Es season begins<br />around April, peaks around July, and tapers off by October (there is<br />also a minor secondary peak in December). The best times for summer<br />6-meter Es are from late morning to early afternoon, and then again<br />from early evening to late evening.<br /><br />If you found the higher bands better early in the period (before the<br />minor to major storminess occurred) than the 10.7 cm solar flux<br />predicted, the reason was probably due to the F region being more<br />ionized than the 10.7 cm flux indicated. During the entire reporting<br />period, the 10.7 cm solar flux hovered around 100, and that equates<br />to a sunspot number of about 50. But the effective sunspot number<br />(SSNe), which is the sunspot number that forces a best worldwide fit<br />between the model of the F region and real-time ionosonde data, was<br />substantially higher--it varied between 75 and 90 during the<br />reporting period.<br /><br />Sunspot numbers for April 10 through 16 were 66, 49, 60, 61, 63, 54,<br />and 40, with a mean of 56.1. 10.7 cm flux was 103.7, 102.6, 102.1,<br />102.4, 102, 100.5, and 98.5 with a mean of 101.7. Estimated<br />planetary A indices were 26, 14, 7, 10, 16, 22, and 31, with a mean<br />of 18.<br />NNNN<br />/EX