CLEMENTS@G.BBN.COM (01/28/86)
Hr Propagation Forecast Bulletin Nr 4 From ARRL Headquarters Newington CT January 27, 1986, Edited by K1BC To All Radio Amateurs BT Through the 26th, solar flux numbers for January are lower than those for the same days in the previous solar rotation on all but 6 days. On 3 of these 6, the figures were the same as the last time around. Unless something unexpected happens this week, January will be about 1 unit per day lower than December. This is not unexpected, in what could be the last full year of this solar cycle, but it does not necessarily follow that the rest of this cycle will show a steady decline. The final months of the 3 other cycles for which accurate flux readings are available do not show a consistent daily dropping off, except on a long term, smoothed basis. From the middle of August to the middle of October 1985, the flux was never above 73, and much of the time it was in the high 60s. September averaged only 69.5. But since the middle of October we have had 4 days in the 90s, and 54 days of 75 or higher. The importance of these statistics is that for the Fall and early Winter DX season in the northern hemisphere, the sun was active enough for fairly good coverage on all bands except 28 MHz for nearly half of the days. On at least one third of the days we could have done fairly well, even on 28 MHz. Solar activity does not rise and fall in smooth or symmetrical curves. It is likely that, except in the few weeks when we move from cycle 21 into cycle 22, we will not see DX conditions generally very different from those we have lived with over the past year or so. For the forecast week, we will be operating with the solar flux and sunspot numbers very close to the minimum quiet sun levels. This means that our nightime DX work will be done mostly on 10 MHz and lower frequencies. The 14 MHz band, always crowded, will tend to be even more jammed in daytime hours. How early it opens, and how late it stays open, will depend upon the solar flux numbers, and they will never be much worse than during this week. We are in a geomagnetically disturbed period as this bulletin is being prepared. This should be over about January 29. The solar flux will be rising by the end of this week. The next major geomagnetic disturbance is expected about February 3 to 4. There were no visible sunspots for the week January 16 to 22. AR -------