SB PROP @ ARL $ARLP021 ARLP021 Propagation de K9LA ZCZC AP21 QST de W1AW Propagation Forecast Bulletin 21 ARLP021 >From Carl Luetzelschwab, K9LA Fort Wayne, IN May 26, 2006 To all radio amateurs
SB PROP ARL ARLP021 ARLP021 Propagation de K9LA Carl Luetzelschwab, K9LA, is filling in this week for regular reporter Tad Cook, K7RA. With respect to space weather, the past week has been relatively quiet. Solar activity was very low (the largest flares were several Class B events) and geomagnetic field activity was quiet to unsettled (the planetary A index stayed below 10). The Sun did have some sunspots this week -- Regions 884, 885, and 886 dotted the solar disk, but they weren't very active. There are also indications that old Region 882 may be coming around again. The forecast for the next several days, Memorial Day weekend, is for continued low solar activity and quiet to unsettled geomagnetic field conditions. The probability of major flares or significantly elevated K indices is low. As a result, there shouldn't be any major propagation surprises. The 40, 30, 20, and 17 meter bands should provide the bulk of domestic and DX contacts, but keep an eye out for sporadic E activity. This weekend is the CQ World-Wide WPX CW contest. The format for this contest is everyone works everyone, with prefixes as multipliers. Although the QSO point structure favors DX contacts, the fact that prefixes are multipliers means domestic contacts can play an important role -- which in turn means domestic propagation can play an important role. Being at the end of May says the probability of sporadic E helping out on 10 meters, and maybe even on 15, for domestic contacts is quite high. We've already had some good sporadic E propagation on 10 and 6 meters in the past week or two -- hopefully it will continue. Look for sporadic E openings around the late morning hours and then again in the early evening hours. For true DX contacts, though, 40 and 20 meters will likely be the 'bread and butter' bands for this contest at solar minimum. Propagation Tidbit -- As we move into summer, we'll see a decrease in daytime F2 region MUFs. This is in large part due to a change in the composition of the atmosphere at F2 region altitudes. Summer brings decreased ratios of O (atomic oxygen) to O2 (molecular oxygen) and of O to N2 (molecular nitrogen). Since the electron production rate at F2 region altitudes depends on the concentration of O, whereas the electron loss rate is controlled by O2 and N2, a decrease in O to O2 and O to N2 ratios leads to lower daytime MUFs in the summer. For more information concerning radio propagation and an explanation of the numbers used in this bulletin, see the ARRL Technical Information Service propagation page at, http://www.arrl.org/tis/info/propagation.html. An archive of past propagation bulletins is at http://www.arrl.org/w1aw/prop/. Sunspot numbers for May 18 through 24 were 0, 15, 29, 30, 32, 48 and 44 with a mean of 28.3. 10.7 cm flux was 73.3, 75.3, 76.2, 77.5, 83.1, 84.2, and 83.7, with a mean of 79. Estimated planetary A indices were 16, 8, 7, 7, 8, 7 and 4 with a mean of 8.1. Estimated mid-latitude A indices were 11, 7, 5, 4, 6, 4 and 3, with a mean of 5.7. NNNN /EX ---------------------------------------------------------- Archives http://www.mail-archive.com/dx-news@njdxa.org THE DXR is sponsored by the North Jersey DX Association. Please visit our website: http://www.njdxa.org/index.php scroll to bottom for subscribe/unsubscribe options ----------------------------------------------------------
