ZCZC AP25
QST de W1AW
Propagation Forecast Bulletin 25 ARLP025
From Tad Cook, K7VVV
Seattle, WA June 20, 1997
To all radio amateurs
SB PROP ARL ARLP025
ARLP025 Propagation de K7VVV
Solar activity is still low. Although average sunspot numbers were up from 18.3 to 30.1 from last week to the current one, average solar flux was down to 70.6 from a low average of 73.1 the week before. Solar flux was below the 90 day average of 74 on every day over the past week.
The projection for this month shows the solar flux staying in the mid to low seventies. No geomagnetic disturbances are forecast.
Now that we are moving into the summertime propagation period, expect Sporadic-E layer openings on 10 meters through August. Because fewer people are using 10 meters now than at the peak of the solar cycle, many 10 meter openings may go unnoticed. While solar flux remains far too low to sustain reliable activity on 10, Sporadic-E skip does provide some interesting short and medium path length openings, with single hop propagation out to about 1,300 miles and multiple hop propagation to about twice that distance.
Sunspot Numbers for June 12 through 18 were 26, 27, 31, 29, 38, 31 and 29 with a mean of 30.1. 10.7 cm flux was 69.6, 70.1, 70.6, 70.7, 72.1, 69.6 and 71.2, with a mean of 70.6, and estimated planetary A indices were 6, 3, 3, 6, 5, 5, and 4, with a mean of 4.6.