Satgen430 Anomalous Propagation by GM4IHJ (BID SGEN430) 21 June 97 Most satellite users are familiar with the use of HF satellites RS10 and RS12 , for the study of anomalous propagation and for opportunities for sub horizon DX. Indeed the use of the 21MHz up 29MHz down of RS12 as a DX satellite of extra ordinary range, is well documented. With G3IOR the leading expert in the field. This DX activity is however, cyclic. At its best when the sun is most active. So does our present situation at the bottom of the solar activity cycle preclude any and all satellite DX opportunities ? The answer would seem to be No. But very few people have perhaps tried to exploit a second approach to satellite DX which relies on RS12s 2m 145.91 MHz downlink. An approach which is presently available to Northern hemisphere stations at this time of year. As this is being written, pm 18 June 97, the low VHF TV signals and the FM signals from Europe are coming into Scotland RST 559 locked video. These signals originate from stations in a wide arc stretching from Madrid in Spain , through northern Italy and onto southern Germany. Which suggests Sporadic E propagation at VHF which can reach 145 MHz, with the SpE region overhead Nantes in western France, Nancy in eastern France and Mannheim in Germany, all roughly 700 to 800 kms from Scotland. This SpE has been present since 0730 utc and is still present at 1500 utc. Whilst RS12 has 3 times gone down to the south of this arc at horizon LOSs of 0954, 1142 and 1327 utc. As RS12 leaves the Scottish footprint heading south its 145.91 signal disappears . But when RS12 has proceeded further south for several minutes the signal may return , when RS12 is 3500 to 4500 kms from Scotland , overhead equatorial Africa and above the horizon in much of southern Africa. Apparently signals from RS12 are seeing the underside of the SpE arc over Europe after a ground skimming hop over northern Africa, and are being propagated on to GM. It is appreciated that northern Europe is particularly well placed for this sort of , SpE warning from southern stations, and, reception of propagation from the satellite via the SpE . This favourable local geography / station location may not be quite so easily available elsewhere in the northern hemisphere. But even in locations which have no belt of VHF FM or TV stations to their south, amateur radio 2m and 6m beacons may be available to give warning when SpE is present. So far this year the 2m signal of RS12 coming out of Africa has been beacon only , except for transmissions from GM on 21MHz being repeated back by the satellite on 2m. Perhaps if word of this admittedly rare propagation reaches stations in southern Africa, they may take the occasional listen to RS12 when European daylight summer time SpE is perhaps going to give a fleeting super DX contact. Noting that the 21 MHz uplink seems to get through weakly to RS12 ,some of the time, on CW from GM.