clements@bbnccq.ARPA (Bob Clements) (01/27/86)
Hr Propagation Forecast Bulletin Nr 3 From ARRL Headquarters Newington CT January 20, 1986, Edited by K1BC To All Radio Amateurs BT The solar flux reached 83, likely to be its highest level in January, on the 16th. It was down to 73 on the 19th, and is expected to be in the 60s later this week. This should make for generally good propagation but with low MUF. 21 MHz should be mildly active, but for only a few hours daily, and to a limited area at any one time, moving westward with the sun. Propagation will be mainly north and south. The 10 meter band will see little activity, except for possible E skip, but this kind of propagation will be infrequent until spring. On the best days there may be brief north/south openings on 28 MHz. For the most favored times, look for the MUF peak hours on the propagation charts in each issue of QST. Sudden increases in geomagnetic activity are likely January 24 to 29. Rising or already high K index values in the WWV propagation bulletins may accompany these, though the conditions may be over unless you spot a rising trend in the WWV information. An early tipoff is a marked increase in fading, which may be observed on the WWV signal before the K index information is actually changed. Users of 50 and 144 MHz may catch auroral propagation on these bands from having heard the wavery or garbled quality of signals on lower frequencies. These effects are most frequent and pronounced in the northeastern states and in adjacent areas of Canada. Auroras commonly follow sudden large increases in solar activity, such as major solar flares. In the lower latitudes there may be no auroral propagation, but the character of VHF propagation will undergo changes, and there may be north/south enhancement on 21 and 28 MHz. The incidence of such conditions will be increasing in the next few weeks, and they tend to recur at approximately four week intervals. American sunspot numbers for January 9 through 15 were between 10 and 13 with a mean of 5.3. A reading of 13 on the 13th followed 22 consecutive days on which no spots were visible. AR