IRTS News for 22nd May 1994 SOLAR MINIMUM PREDICTION ------------------------ Many operators will have experienced the low level of sunspot activity in recent times despite the fact that this minimum should occur in 1997 if the 11 year cycle predictions are to be followed. Extrapolation of the present trend suggests that the sunspot minimum will be reached some time in 1995 - the previous minimum was in 1986. The daily values of the 10.7 cm radio flux in September continues a rapid trend that has been present since March. This trend and values of flux resemble the daily 10.7 cm flux values observed in 1984. That was only nine years ago, reinforcing tentative predictions that the present cycle will end after only nine years, becoming the shortest cycle in 200 years. The last cycle recorded at near nine years in length was cycle no. 3, which peaked in 1778. The possibility of a nine year cycle is presented after updating comparisons among the five cycles for which there are 10.7 cm flux data. The cycles were plotted under each other on a single graph, placing each in alignment by the reference of times of abrupt drop in flux that has occurred at the end of the maximum phase of each cycle. The present cycle revealed this drop early in 1992. Following the data from the overlays of each graph it has been observed that there is a possibility of a constant interval of 3.5 years between the abrupt drop in flux levels and the time of the sunspot minima. Using this supposition, the date of the sunspot minimum would be in the last quarter of 1995, resulting in a nine years cycle. The most anomalous time of starting minimum is that of the present cycle, suggesting that the cycle had a true start eight to nine months earlier than the September 1986 minimum. In a separate comparison between the present and previous cycles, using smoothed sunspot numbers, it was noticed that the best match was achieved with a shift of eight months later than the time of the previous minimum. SOUTH DUBLIN RADIO CLUB ----------------------- Two lectures have been arranged by SDR for May. They will be held on 24th and 31st, and both will be by Con Hunter EI9V. Con expects to cover a wide range of topics, including propagation and antennas, subjects of great interest to radio experimenters, and of which Con has considerable experience and expertise. All are welcome to attend the lectures, both at 8.30 pm. DONEGAL (TIR CONAILL) ARC ------------------------- With the AGM '94 already logged in the history of IRTS as a huge success, there is continuing euphoria in Donegal following the recent appointment of two Donegal experimenters to office in the Society: Ken McDermott EI4DW as vice-president and assistant secretary, and Danny Bonner EI6GS as head of the new sub-committee to promote the use of Irish on the amateur bands and chairman of the IARUMS sub-committee. Meanwhile, in Yeats's county, Martin O'Dea EI3FI, of Grange, Co. Sligo, succeeds Bill Somerville-Large EI9FK as honorary secretary of the Society. CORK ARC -------- Last week, a lecture and demonstration of the conversion and tuning of PMR equipment was given by Con EI7DMB, following the showing of a video entitled "Getting Started on Packet Radio." There was a huge attendance, and the group had to be moved to another room. While giving the talk, Con tuned the Pye Westminster transceiver on to 2m, demonstrating the ease with which it can be done. The dmonstration continued with a discussion on how the Westminster could be converted for use as a 2m repeater, using the discriminator output to operate a relay to trigger the transmit side, enabling the rig to be used as a talk-through repeater. The rugged construction of the Pye ex-commercial gear was discussed, as was the fact that the gear was so easy to convert and repair within the copacity of the relative newcomer to the hobby. Following the success of this lecture, it is hoped to cover the conversion of rigs in the future. The second part of the series on packet radio will be shown this week, and again a large attendance is predicted. RADIO NEWS ITEMS URGENTLY REQUIRED ---------------------------------- Once again an appeal goes out to all clubs and groups around the country for items of interest which can be included in the radio news bulletins. ITEMS FOR INCLUSION ------------------- That concludes the bulletin for this week. Items for inclusion in the radio news should be sent to Steve Wright EI5DD, c/o Dept. of Pathology, Regional Hospital, Galway. Fax messages may be sent to EI5DD at 091 24216. All such items will be forwarded to Dave Moore for inclusion in the printed news. Items for the printed news only should be sent to Dave Moore EI4BZ, QTHr, or phoned to 021 632444 (daytime), or 021 883555 (evenings). Items may be sent by packet radio to EI4BZ at EI7DKB-5. Fax messages may be sent to 021 632730.