ZCZC AP34
QST de W1AW
Propagation Forecast Bulletin 34 ARLP034
From Carl Luetzelschwab, K9LA
Fort Wayne, IN August 17, 2001
To all radio amateurs
SB PROP ARL ARLP034
ARLP034 Propagation de K9LA
Filling in this week for Tad, K7VVV, is Carl Luetzelschwab, K9LA.
This report is for the period Friday August 10 through Thursday August 16.
The Penticton, British Columbia, 10.7 cm solar flux, following the sun's 27-day rotation period, peaked at 165 early in the period, and gradually decreased to 143 by the end of the period.
Solar activity for the period was mostly at low levels. Regions 9562, 9566, 9574, and 9577 produced several class C flares. Class C flares are the lowest category of X-ray flares at 1-8 Angstroms (wavelengths that can ionize the D region), and generally have little impact to propagation.
Geophysical activity for the period was quiet to unsettled during the early part of the period, with the planetary Ap index at or less than 14. Activity was unsettled to active during the middle of the period due to a coronal mass ejection (CME) on August 9, with the Ap index moving up to around 20. Activity at this level could reduce MUFs (maximum usable frequencies) a little at mid and high latitudes. Activity returned to quiet to unsettled at the end of the period. A CME that occurred on August 14 could move the geomagnetic field up to active to minor storm levels in the next day or two.
Solar Cycle 23 update: The maximum of Cycle 23 occurred in April 2000 at an SSN (smoothed sunspot number) of 121. Cycle 23 continues its descent to minimum, which is predicted to be in the 2006 to 2007 time frame. The most recent data shows the SSN to be 109 for January 2001. For propagation predictions for this month (August 2001), an SSN of 94 is recommended for best results.
Now is the time to concentrate on the higher bands - especially 12 and 10 meters in the fall, winter, and spring seasons. In a couple years things are going to be pretty bleak on these frequencies, with only very occasional openings. On the other end of the spectrum, low band aficionados still have several years before things get REALLY good on 160 and 80 meters.