QST de W1AW
Propagation Forecast Bulletin 30 ARLP030
From Tad Cook, K7VVV
Seattle, WA July 25, 1997
To all radio amateurs
SB PROP ARL ARLP030
ARLP030 Propagation de K7VVV
This week finally saw a welcome rise in solar activity and the accompanying improvement in HF radio conditions. Solar flux rose above 70 on July 19, was above 72 on July 22, and then at 1700, 2000 and 2300 UTC on July 23 it reached 75.6, 75.7 and 75.8, and at the same times on July 24 it was 77, 78.7 and 79. The 2000 UTC measurement at Penticton, BC is the one reported in this bulletin.
The really great news is that with three active regions on the solar disk, this trend is expected to continue, with flux values around 80, 82 and 82 expected for July 25, 26 and 27. Fortunately, there is no expected rise in geomagnetic indices to go along with the increased activity, so HF conditions should remain stable.
R. Brendle wrote to say that he operates several commercial and GMRS UHF repeaters in Eastern Nebraska, and that the seasonal ducting this year is the longest and most sustained he has ever seen. Normally this only happens during overcast and humid conditions during a severe weather watch, but the most recent period lasted over two weeks.
On HF, look for excellent worldwide propagation over the next few days with higher solar flux and continued low A and K indices.
Sunspot Numbers for July 17 through 23 were 11, 11, 0, 12, 0, 11 and 31 with a mean of 10.9. 10.7 cm flux was 69.9, 70.1, 71, 71.2, 71.3, 72.2 and 75.7, with a mean of 71.6, and estimated planetary A indices were 8, 10, 11, 6, 5, 4, and 5, with a mean of 7.