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 29 Message-ID: <19054@mgweed.UUCP> Date: Mon, 22-Jul-85 19:23:45 EDT Article-I.D.: mgweed.19054 Posted: Mon Jul 22 19:23:45 1985 Date-Received: Thu, 25-Jul-85 05:13:35 EDT Organization: AT&T Information Systems - Montgomery Illinois Lines: 36 qst de k9eui hr propagation forecast bulletin nr 29 from arrl headquarters newington, ct july 21, 1985 to all radio amateurs bt the solar flux curve is following a trend that began in may. early in the month there was a marked rise, followed by a sharper decline to very near quiet sun values. in the low period that began july 15, the flux curve is almost exactly superimposed on that for 4 weeks earlier. this trend is expected to hold, with flux values close to 70 until about july 27th, followed by a steep rise in early august. about half of the sun has been active and the other half almost quiet for the past 3 months. the active periods bring very frequent geomagnetic disturbances and unstable propagation. the calm, like the period now at hand, gives more stable conditions, but with lower muf. this should be with us through the rest of july, with more variable propagation again in early august. sporadic e layer ionization is now declining, so 21, 24, 28 and 50 mhz will be less active through the rest of the summer. a more direct relationship between solar flux levels and dx conditions will be apparent as we move into august, and increasingly clear in early fall. usefulness of the qst propagation charts will improve, especially where high latitude paths are involved. there is some possibility of better hf dx conditions in late 1985 than were experienced in the same months of 1984. that was a time of exceptionally low solar activity for less than 9 years into cycle 21. american sunspot numbers for july 11 to 17 were between 3 and 50 with a mean of 18 ar