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!linus!philabs!cmcl2!seismo!harvard!talcott!panda!grkermi!genrad!decvax!bellcore!sabre!zeta!epsilon!gamma!ulysses!mhuxr!mhuxn!ihnp4!mgnetp!mgweed!rjr From: rjr@mgweed.UUCP Newsgroups: net.ham-radio Subject: arrl propagation forecast bulletin nr 24 Message-ID: <17981@mgweed.UUCP> Date: Mon, 17-Jun-85 20:03:42 EDT Article-I.D.: mgweed.17981 Posted: Mon Jun 17 20:03:42 1985 Date-Received: Sun, 23-Jun-85 08:09:18 EDT Organization: AT&T Consumer Products - Montgomery Illinois Lines: 35 qst de k9eui hr propagation forecast bulletin nr 24 from arrl headquarters newington ct june 16, 1985 to all radio amateurs bt as discussed in last weeks bulletin, the solar flux curve is beginning another downward trend. numbers have been close to those of 27 to 28 days ago except that since june 11th the decline has been more rapid. the flux number for june 16 was 78, ten points below that for may 19, when the sun was in a similar position with respect to the earth. flux values near the quiet sun level are expected in the last few days of june. the effects of lower solar activity are minor in the summer months. skip tends to be longer on the lower amateur bands as solar activity declines. on 21, 28 and 50 mhz the early summer sporadic e ionization produces almost daily short skip, over 400 to 1300 miles, depending on the band and on the ionization density. the latter reaches its peak in late june and early july. watch 144 mhz for e skip opportunities this season. the lower solar activity currently makes for less disturbance of the earths magnetic field, and this is good for nearly all amateur communications over other than local distances. undoubtedly, summer is the season for increased thunderstorm activity, and higher noise levels are observed on all frequencies much of the time. storm noise can be propagated over long distances on the lower frequencies. storm static is essentially a local phenomenon on frequencies above the muf at the time. american sunspot numbers for june 6 through june 12 were between 31 and 59 with a mean of 40.3 ar