Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site mgweed.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxj!ihnp4!mgnetp!mgweed!rjr From: rjr@mgweed.UUCP (Bob Roehrig) Newsgroups: net.ham-radio Subject: arrl propagation forecast bulletin nr 39 Message-ID: <12548@mgweed.UUCP> Date: Mon, 24-Sep-84 19:28:02 EDT Article-I.D.: mgweed.12548 Posted: Mon Sep 24 19:28:02 1984 Date-Received: Thu, 27-Sep-84 02:30:15 EDT Organization: AT&T Consumer Products - Montgomery Illinois Lines: 30 qst de k9eui hr propagation forecast bulletin nr 39 from arrl headquarters newington ct september 24, 1984 to all radio amateurs bt solar flux levels of 75 or lower september 13 to 20 almost exactly duplicate a significant low in april 1977, less than a year from the end of cycle 20. looking back to september 1975 shows flux high, low and average values to have been very similar to those of september 1984 thus far. these comparisons suggest that cycle 21 could be shorter than the 11.2 year average, but flux records available (garble) show that cycles 18, 19 and 20 all had brief periods of substantial sunspot activity in their final two years of life. we may be on the verge of such a burst. though visible sunspot activity has been very low for the last two weeks, there is action on the sun currently. a major geomagnetic storm, in progress as this bulletin was being prepared, narrowed the useable frequency spectrum severely. things may be better soon. the solar region now facing us brought a flux rise to 93 four weeks ago. such levels in late september and in early october could work wonders for 21 and 28 mhz which could last through about october 5. american sunspot numbers for september 13 through 19 were between 0 and 1 with a mean of 0.1 ar