Satgen 626 SatPropagation Study by GM4IHJ (BID SGEN626) 2001-03-24 The present solar cycle appears to have passed its peak. It has not been an outstandingly strong cycle. Indeed it has been more of a damp squib. More like one of the 1960s cycles rather than the high solar activity peaks of the 50s, 70s and 80s cycles. None the less, given the tremendous improvement in equipment and the explosion in available solar information. This HF/VHF propagation enthusiast has had a feast of excellent experiment opportunities. Enhanced by Fast Forier Transform Digital Signal Processing of the received signal , via a JRC NRD 535 Rx and 3 element beam , compared with the previous outfits - Hallicrafters 40s/50s latest/greatest vacuum tube superhet ,and Yaesu FRG7, wire antenna and mark 1 earball of the 70s. Mid Latitude HF/Low VHF backscatter. Using the excellent RS12/13 satellite and FFT display of signal. The regular appearance of electron density enhanced ionopheric bands across the middle latitudes of the Northern Hemisphere (25N to 45N for the most part). Has firmly established this phenomena as an excellent aid to non great circle HF DX. First reported by 6m/10m users back in the 70s cycle peak ( yes Gs were restricted to 10m cross band to W/VE 6m). The presence of these bands in the daylight ionosphere was further confirmed by Uosat electron density measurements. Although we had to wait until the advent of FFTDSP displays of signal frequecy, strength and bandwidth, could add the complete picture during this recent cycle peak. Antarctic Signal paths. It had long been appreciated ( W5LFLs sputnik observations in the late 1950s refer ), that HF signal returns from locations near the antipodes were a regular feature of solar cycle peak propagation. With signals appearing out of the blue at northern stations, as HF satellites passed near the south pole. What has become clear however, by way of FFTDSP plotting, is that during the recent solar cycle peak and continuing even now as the solar activity declines, is that very few signals are received from the satellite overhead the actual station antipodeal point. Almost all the signals are heard as the satellite makes its closest approach to the south pole often with very odd high or low doppler shift. Auroral Zone Propagation paths. The availability of 10 or 20 minute FFT tracks, has allowed production of continuous records, without the tedium of continuous listening and tuning, over large parts of the satellites orbit. In a typical 14 minute ascending pass near Scotland . The signal usually goes wide band shortly after the satellite overflies the nearer lower edge of the auroral oval, providing continuation of reception although the satellite is going below the station horizon. Minor discontinuities occur but not complete loss as the satellite overflies the further , remote edge of the auroral oval. Then it is regularly tracked down to 45N latitude near Japan or Kamchatka, or on other orbits, over Alaska and thence down the North Pacific to disappear as it passes somewhere west of Vancouver Canada. Hopefully RS12/13 will survive for a few more years but we will have to look elsewhere for good HF/VHF experiments in the next solar peak.