ZCZC AP30
QST de W1AW
Propagation Forecast Bulletin 30 ARLP030
From Tad Cook, K7VVV
Seattle, WA July 24, 1998
To all radio amateurs
SB PROP ARL ARLP030
ARLP030 Propagation de K7VVV
W9JJ wrote to point out that the statement in last week's bulletin ARLP029 that a K index of six was bad really only applies to HF radio. For VHF operators, geomagnetic disturbances often produce exciting propagation. A good VHF rule is when the K index is high to point your antenna toward the closest polar region, north in the northern hemisphere and south in the southern to take advantage of auroral propagation.
Estimated Planetary A indices of 37 on July 16 and again a week later on July 23 were certainly good times to listen for those gravelly auroral signals on VHF. W9JJ reported that when he lived in Wisconsin he would frequently find auroral propagation on 2 meters when the K index was only three or higher. When the K index was six it meant a solid 2 and 6 meter opening.
VHF has been producing a lot of interesting propagation lately, but not just from auroras. A lot of Hawaiian signals have been reported on the West Coast due to tropospheric ducting. WA6KLK, K6FV and N6RZ reported hearing the KH6HME 2 meter beacon in Northern California early in the week, and later it was copied by a number of Pacific Northwest stations.
A number of stations reported 6 meter openings to Japan. JH2COZ worked K7CA in Nevada and heard many JA stations calling N5JHV in New Mexico and K7FF in California. G0JHC in Northwest England heard a VE8 6 meter beacon at S7.
KJ6KO has some .WAV files with recordings of the 6 meter openings from California to Hawaii at http://www.innercite.com/~kj6ko.
Over the next week look for a rising solar flux, reaching 120 around July 28 to August 1. Flux values are expected to drop below 110 around August 7, and above 110 again after mid-August. Look for disturbed geomagnetic conditions again around July 30 and 31.
Sunspot Numbers for July 16 through 22 were 113, 89, 76, 62, 90, 125 and 145 with a mean of 100. 10.7 cm flux was 106.2, 100.3, 99.2, 103.6, 111.8, 110.3 and 114.1, with a mean of 106.5, and estimated planetary A indices were 37, 9, 5, 8, 6, 15, and 8, with a mean of 12.6.