Satgen630 Auroral Transients by GM4IHJ (BID SGEN630) 2001-04-21 Professional literature has for some time been describing short duration daytime auroral events, which seem to be the product of solar wind shock excitation of the earths magnetosphere. So in an effort to find out just what this might mean for radio amateurs, an experiment was organised at IHJ 56N 3.6W . The equipment used consisted of a 3 element 6m beam antenna pointed due north, feeding a Drake R8E receiver tuned to a Norwegian television carrier producing a roughly 700Hz note when set to 48.2533 MHz CW reception. Other suitable carriers audible in NorthWest Europe are 48.2396; 48.2463 ;48.2501 ; 48.2576 ; 49.7403 and 49.7612 MHz. Depending on your location some or all of these carriers should be audible via meteor scatter from about 0600 to 2200z . So there is no need to tune around . Though please note that meteor scatter central frequency and auroral transient frequency may differ one from the other, by as much as 100 Hz up or down The signal is displayed on the computer using AF9Y FFTDSP software , integration time 1, for 2+ minutes of display . Longer integration time does allow the operator to get on with something else for a few minutes. But the reduced display length of < 70 seconds of individual transients can make them difficult to distinguish from QRM. Transient auroral signals are almost always very broad , often 100 Hz wide , and if you are listening to the audio the rough T1 or T2 signal is very obvious. While their occurence particularly in the mornings when conventional long duration auroral signals are very rare, is highly diagnostic. The period 28 March to 16 April 2001, may be atypical. There have been radio aurora almost every night, suggesting high solar wind activity. So the experiment will be repeated when the Sun is quieter, to see what happens then. But during this first 20 day run there were 5 of these short lived but very obvious transient auroral events . One on 31 March lasted for 3 minutes and the signal was 10 dBs over noise. But the other 4 events were all less than 70 seconds duration and barely reached 5 dBs over noise. As yet no attempt has been made to check for any sort of correlation between these events and solar wind shock events reported by professional observatories. By coincidence , there have recently been reports in professional journals of transient auroral events over the poles of the planet Jupiter. In 1999 and 2000 events occured at Jupiter whereby a rapid exponential rise in localised emission was seen to commence polewards of Jupiters normal auroral oval. The emission being recorded by the Hubble Space Telescope Imaging Spectrograph. As yet there is no exact correlation possible between these Jupiter events and the passage of solar wind shocks observable from the Earth . Noting that the ACE satellite which reports these solar wind bursts as they approach the earth has been on a quite different solar azimuth from that of Jupiter , and solar wind variations in one direction rarely coincide with changes in other directions . None the less better alignments will occur in future whereby a shock at the earth may be seen to go onward and eventually collide with the Jupiter magnetosphere.