ARLP028 Propagation de K7VVV: July 12, 1997

Propagation Forecast Bulletin 28 ARLP028
From Tad Cook, K7VVV
Seattle, WA July 12, 1997
To all radio amateurs

ARLP028 Propagation de K7VVV

Conditions are still flat. The average solar flux, sunspot number and planetary A index hardly varied from last week to this week. Because short term forecasts are based upon the previous solar rotation, no activity is predicted for the next month, except for a possible slightly unsettled period around July 23 or 24.

A card arrived from W7ZT in Arizona noting that he didn't notice even any seasonal sporadic E skip on the higher frequencies over the Field Day weekend, and an interesting letter came from W4VOS concerning comparisons of previous solar cycles. He noted that it is mostly true that each odd-numbered solar cycle was greater than the previous cycle. We are now awaiting activity from cycle 23, so this is a cause for some hope. But with a chart from a 12 year old issue of a DX newsletter which showed cycle data provided by KH6BZF, W4VOS commented that cycle 9 around 1850 was smaller than cycle 8, and cycle 5 around 1805 was much smaller than cycle 4. Will cycle 23 be the third cycle in history to break this rule? Let us hope not.

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Sunspot Numbers for July 3 through 9 were 12, 12, 11, 11, 26, 25 and 31 with a mean of 18.3. 10.7 cm flux was 69, 69.7, 69.7, 71.8, 71.7, 71.2 and 70.2, with a mean of 70.5, and estimated planetary A indices were 7, 7, 4, 4, 14, 5, and 11, with a mean of 7.4.