ZCZC AP05
QST de W1AW
Propagation Forecast Bulletin 5 ARLP005
From Tad Cook, K7VVV
Seattle, WA January 29, 1999
To all radio amateurs
SB PROP ARL ARLP005
ARLP005 Propagation de K7VVV
Solar activity was down slightly this week when compared to last. Average sunspot values were 35 points, lower but solar flux was off by less than six points. Average solar flux for the previous 90 days was 140.1, and daily solar flux values were below this level on the last three days of the reporting week. Expect solar flux to continue lower at 112, 110 and 110 for this Friday through Sunday. Planetary A index for the same three days is projected to be 8, 5 and 8, which is not too bad for the CQ WW 160-Meter DX CW contest this weekend.
The projected solar flux for Saturday and Sunday of 110 is quite low, all of 30 points lower than the average for the 90 days previous to the reporting week. Flux values also dipped down to this level on January 10, but prior to that had not been this low since late October. Solar flux is expected to rise next week, to above 130 around February 8, above 140 three days later, and around 155 by mid-month. Look for unsettled geomagnetic conditions around February 9-11 and February 19.
What was it like a year ago? During the same week last year average sunspot numbers were 17 points lower and average solar flux was about 55 points lower.
In VHF news, WP4O in Puerto Rico heard a 6 meter station in Paraguay on January 28. On Monday he reported contacts with a number of South American stations on 2 meters.
A wire service story reported this week that all experiments aboard the SOHO spacecraft have halted since the December 21 gyroscope failure. The craft is burning extra fuel to fire thrusters, and is being exhausted at about 50 times the normal rate. This could cause total depletion of fuel by mid-year. There is a chance that experiments may resume in early February.
Users of Scott Craig's solar plotting program noticed a problem when trying to automatically load data from last week's bulletin. The problem was caused by the use of a phrase that the program depends upon to pull data out of what is usually the last paragraph, but this phrase also appeared in an earlier paragraph. I dare not repeat it here at the risk of causing the problem again, since Scott's software depends upon seeing that phrase in only the paragraph with the solar data. Scott also has another update to the software this week at http://edge.net/~scraig/sol.htm. You can either enter last week's data manually, or edit ARLP004 so that only the paragraph with the solar data is scanned by Scott's software.
Sunspot Numbers for January 21 through 27 were 134, 141, 117, 107, 81, 47 and 64 with a mean of 98.7. 10.7 cm flux was 175.3, 177.9, 165.9, 161.8, 138.1, 133.2 and 125.4, with a mean of 153.9, and estimated planetary A indices were 5, 10, 16, 13, 9, 4 and 9, with a mean of 9.4.