ARRL

ARRL Propagation Bulletin ARLP052 (2002)

SB PROP @ ARL $ARLP052
ARLP052 Propagation de K7VVV

ZCZC AP52
QST de W1AW  
Propagation Forecast Bulletin 52  ARLP052
From Tad Cook, K7VVV
Seattle, WA  December 13, 2002
To all radio amateurs 

SB PROP ARL ARLP052
ARLP052 Propagation de K7VVV

W8GF pointed out in an email that last week's bulletin showed solar
flux and sunspot number averages for the first eleven months of the
year, but only ten values were displayed. I discovered that May 2002
values were missing from both lists. Looking back, ARLP046 also had
this same problem with missing May numbers.

So here is the corrected list. Average sunspot numbers during
January through November were 189, 194.5, 154.3, 144.4, 204.1, 146,
183.5, 191, 206.4, 153.9 and 159.8. The missing value last week was
204.1 for May 2002. Average solar flux was 227.3, 205, 179.2, 141.4,
178.4, 148.7, 174.4, 183.9, 175.8, 167 and 168.7. The missing flux
value was 178.4 for May 2002.

This week conditions improved for HF, with slightly lower
geomagnetic indices (the daily average planetary A index down from
13.6 to 9.7) and with solar flux and sunspot numbers up. Average
daily sunspot numbers were up nearly 16 points, and average solar
flux was up by nearly 8.

Conditions look good for the ARRL 10-Meter Contest this weekend with
moderate geomagnetic conditions and a rising solar flux.  Predicted
solar flux values for Friday through Monday are 155, 160, 165 and
170.

Right now the days are very short, and they will keep getting
shorter for the next week. Long nights are good for 40-meter
propagation, but the higher frequencies close early. The winter
solstice will come to North America on December 21, and after that
we can watch the slow progression toward springtime propagation.

Sunspot numbers for December 5 through 11 were 153, 112, 106, 150,
189, 142, and 171, with a mean of 146.1. 10.7 cm flux was 148.7,
148.2, 151.1, 154.4, 156.3, 161.4, and 152.3, with a mean of 153.2.
Estimated planetary A indices were 9, 10, 16, 12, 8, 7, and 6, with
a mean of 9.7.
NNNN
/EX