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!mhuxr!mhuxn!ihnp4!mgnetp!mgweed!rjr From: rjr@mgweed.UUCP (Bob Roehrig) Newsgroups: net.ham-radio Subject: arrl propagation forecast bulletin nr 39 Message-ID: <20729@mgweed.UUCP> Date: Tue, 1-Oct-85 19:21:56 EDT Article-I.D.: mgweed.20729 Posted: Tue Oct 1 19:21:56 1985 Date-Received: Thu, 3-Oct-85 04:47:10 EDT Organization: AT&T Information Systems - Montgomery Illinois Lines: 37 qst de k9eui hr propagation forecast bulletin nr 39 from arrl headquarters newington ct september 30, 1985 to all radio amateurs bt with one day to go as this bulletin was prepared, the solar flux average for september is 69.6. this will not change significantly when the flux reading for the 30th is added. we will then have our first monthly average under 70 since july 1976, the start of cycle 21. the present calm spell began august 11, when a nine year low of 67 was recorded. the flux has been no higher than 73 since, and there have only been 3 of these. more important, there were 26 days under 70 in the past 2 months including one 66 and six at 67. several short lived sunspots appeared several times but the most recent visible spot activity of any consequence came in late july. some solar emissions that cause fluctuations in the earths magnetic field and increased attenuation of hf signal levels in the higher latitudes cannot be seen in the conventional white light view of the sun. thus the sunspot record is not a completely reliable indicator for hf propagation prediction. the very erratic hf conditions of late september were typical, with about 5 periods of 1 to 2 days each of very good and very bad propagation, following one another in rapid succession. there will be more of this in october, after some fairly consistent good times early in the month. it is believed that the almost total absence of sunspots recently is a temporary phenomenon, probably not an indicator of an early end of cycle 21. the best 8 weeks of the year are at hand, in any case. american sunspot numbers for september 19 through 25 were between 0 and 10 with a mean of 3.4 ar Brought to you by Super Global Mega Corp .com