Satgen108 Low Earth Orbit Satellites and Glasgow Shuttle 22 April 91 Uosat3 has now switched to alternate use of a special non radio amateur frequency by the VITA Medical Aid Charity. When VITA users are active, the radio amateur link goes off momentarily. Lusat and Pacsat are suffering from buffer loss problems, which can only be cured by redesign of the software. Dove has still not recovered/reset from the crash which occured around the time of the big aurora on 24 March. Unfortunately the reset is being hampered by at least two major hardware failures on Dove. RS12 is doing well on KT mode 21MHz up 29MHz down , beacon 29.408MHz . It gives excellent night time and early morning passes on its downlink 29.41 to 29.45. It suffers during the day from Polar scintillation when above 70N, and it also has difficulty getting a good signal into UK in daylight if the ionosphere is thick (Maximum usable Frequency is high). As we go from winter to summer conditions the good sub horizon propagation via the ionosphere is disappearing. Up to April 12th Antarctica to UK was open nearly ever day but over the last week this has disappeared and may not be back until September/October. But there is still the second form of subhorizon propagation whereby the satellite is heard in low MUF conditions over Canada around noon utc and , east of UK in the early evening. At these times the sat is up to 10 degrees below the UK horizon but it still manages to get both beacon and user comms signals into UK. This mode may be due to atmospheric refraction and/or an anomalous form of ionospheric refraction. Just which is involved will possibly be proved by doppler measurements of the satellite beacon which are now underway. So if you hear any of these sub horizon episodes please note the zero beat frequency of the beacon , and also note the normal beacon frequency which you hear on an evening closest point of approach , for comparison. RM-1 is sending CW telemetry on 145.822MHz but have not heard much else from it lately. GLASGOW SHUTTLE Shuttle Discovery should launch on the morning of 23rd April for flight STS 39 which is scheduled to overfly Glasgow as it carries out 8 days of Star wars trials. There has been no report of likely amateur radio activity but there should be plenty of microwave (TDRS) and , possibly some UHF activity. Details of frequencies were given in Satgen bulletin number 101, which you can get from GB7SAN rather than coming all the way up to me ( it may also be available on GB7WRG for stations in North of England). I will publish Keps , orbit times and potential visual tracking opportunities if I get them in time. In addition if any of the star wars packets are heard I will report them in special short bulletins. If STS 39 sticks to its original flight plan it could be a good visual target in the pre dawn very early morning sky 24 to 30th April. Please note it will pass at a much higher elevation in the sky than does the more regular Mir Space station ( see IHJ Mir Manual and/or RSGB Space Radio Handbook for visual tracking tips). EG STS 39 will pass north of G stations on its 3 best orbits. See you at Kelso on May 5th on GM4JJJ's Pack-Age stall. 73 de John GM4IHJ @ GB7SAN