Satgen 213 Progress Report - 3PT New HF Propagation by GM4IHJ 24 Apr 93 BID of this msg is SGEN213 Please use that BID if you retransmit the msg At the end of the first full winter season of 3PT = Polar Plasma Propagation Tests using satellites RS10 and 12 , a picture is emerging of when we can expect these events and what form they will take. NM7M pointed out in Nov 92 that 29MHz sat beacons were being heard over the pole when the pole was in total winter darkness , with a very thin "night time" ionosphere. He asked were was the ionisation coming from ? Professional researchers had the answer. Having been paid to check the polar ionosphere for "events" which upset over the horizon HF radars and such like , they had observed plasma, being intruded into the polar ionosphere above the longitude of local magnetic noon, on their ionosondes and riometers. They suggest that the plasma enters the outer layers of the Earth's magnetic field above the tropics, when the Interplanetary magnetic field has SOUTH polarity. The plasma travels up between the magnetic field lines to the polar cusps where it finds open field lines down to the polar ionosphere. The following tables show how many times this last winter, satellite DX was possible out to a maximum of 7500 kms. Events seem to come all at once, or, not at all. PLEASE NOTE THAT THESE EVENTS HAVE NOTHING WHAT SO EVER TO DO WITH POLAR AURORA. Events 3. X X X 2. XXX X XX X 1.XX X XXX X XXXXXX X XXX XXXX X XX X ........................................................................ 1 1 2 2 1 6 1 1 2 2 3 5 1 1 2 1 6 1 6 1 6 1 6 1 1 6 1 November 1992 . December 1992 . January 1993 7. X 6. X 5. X X 4. X X X X X X 3. XX X X X XX X X 2. XX X X XXXX X X X X XX 1. XXXX X XXXX X X X XX X X XX ........................................................................ 6 1 1 2 2 1 6 1 1 2 2 3 5 1 1 1 6 1 6 1 6 1 6 1 0 5 February 1993 . March 1993 . April 1993 Each X represents an RS10 or RS12 orbit heard when it was sub horizon beyond the pole. Event days come in groups, with big gaps in between, ( Eg big gap 11 Jan to 15 Feb 93). More than 2 events per day ,signifies propagation present for more than 2 hours. More than 4 events = propagation present for 4 hours or more. Which suggests - HF propagation over the pole from UK was present for nearly 6 hours on Feb 27th 93. Several unusual terrestrial stations were heard during this opening, but as yet , few terrestrial DXers appear to be aware of this Polar Plasma Propagation phenomena. 73 de GM4IHJ @ GB7SAN