ZCZC AP30
QST de W1AW
Propagation Forecast Bulletin 30 ARLP030
From Tad Cook, K7RA
Seattle, WA July 25, 2003
To all radio amateurs
SB PROP ARL ARLP030
ARLP030 Propagation de K7RA
Geomagnetic activity settled down over the past week. The average daily planetary A index dropped by nearly half from the previous week, from 29.1 to 16.1. Average daily sunspot numbers went up from 140 to 195.3 and average daily solar flux rose from 125.6 to 147.7.
Solar flux declined from Wednesday to Thursday, July 23 to 24, from 144.1 to 129.2. Predicted solar flux for Friday through Monday, July 25 to 28 is 120, 125, 125 and 130. Planetary A indices for those same days is predicted at 12, 15, 12 and 15, but is expected to rise next week to between 20 and 25.
The sunspot count rose last week because of rapid growth of sunspot groups 409 and 410 about a week ago. Sunspot 410 began to decay around July 22. The predicted rise next week in geomagnetic indices is due to a solar wind that earth will enter around July 27.
More news of VHF openings is in. Pat Rose, W5OZI said on July 24, from 0046 to 0052z (which was Wednesday night in North America) he worked five Japanese stations on 6-meters. Pat said that in 18 years on 6-meters he has never had E-layer propagation to Japan from his home in Junction, Texas, about 120 miles west of Austin. Pat says the approximate distance to the Japanese stations is over 10,300 km, or 6,400 miles, and believes it took six hops off the ionosphere.
Sunspot numbers for July 17 through 23 were 189, 193, 178, 224, 219, 200, and 164, with a mean of 195.3. 10.7 cm flux was 138.7, 139.7, 146, 157.3, 155.6, 152.5, and 144.1, with a mean of 147.7. Estimated planetary A indices were 22, 14, 26, 19, 12, 9, and 11, with a mean of 16.1.