ARRL

ARRL Propagation Bulletin ARLP027 (1999)

SB PROP @ ARL $ARLP027
ARLP027 Propagation de K7VVV

ZCZC AP27
QST de W1AW  
Propagation Forecast Bulletin 27  ARLP027
From Tad Cook, K7VVV
Seattle, WA  July 2, 1999
To all radio amateurs 

SB PROP ARL ARLP027
ARLP027 Propagation de K7VVV

Solar flux, and especially sunspot numbers, took a huge leap over
the past week.  Average sunspot numbers almost doubled, with a jump
from 138.9 last week to 272.  Sunday had the highest sunspot number,
341.  Average solar flux was up almost fifty points to 198.6
compared to the previous week.  Saturday and Sunday's big numbers
were quite an event for Field Day weekend.

These numbers are a new record for this solar cycle.  The last time
sunspot numbers were any higher was on February 1, 1992, when the
sunspot number was 363.  Solar flux hasn't been this high since
February 29, 1992 when it was 218.

The end of June was also the end of the second quarter for 1999.
Average sunspot numbers for the last quarter of 1998 through the end
of June were 99.1, 96.1 and 147.2.  Average solar flux for the same
three quarters was 136.9, 136.7 and 145.  You can see a more
dramatic rise in the monthly numbers over this quarter.  April
through June average sunspot numbers were 92.9, 140.6 and 208.3, and
average solar flux for the same period was 117.2, 148.4 and 169.8.
This indicates a great upward trend.  Unfortunately, the last time
we looked at these numbers in ARLP024 there was a bit of confusion
regarding sunspot numbers.  The monthly averages reported in that
bulletin were for international sunspot numbers, which are lower
than the NOAA Space Environment Service Center numbers always
reported in this weekly bulletin.

The forecast for the next few days, Friday through Sunday has a
solar flux of 195, 190 and 180, and planetary A index of 12, 10 and
8.  Beyond the weekend look for flux values below 160 after July 8,
rising above 160 after July 18 and above 180 after July 24.

Sunspot numbers for June 24 through 30 were 229, 260, 310, 341, 268,
259 and 237 with a mean of 272.  10.7 cm flux was 185, 200.8, 199.5,
207.4, 196.6, 191.3 and 209.5, with a mean of 198.6, and estimated
planetary A indices were 6, 5, 17, 21, 26, 9 and 5, with a mean of
12.7.

The path projection for this week is from Seattle, Washington.

To Europe, 40 meters possibly 0300-0500 UTC, 30 meters 0300-0530
UTC, 20 meters 2300-0900 UTC, 17 meters 1330-0730 UTC (best 0230-
0530 UTC), 15 meters possibly 1830-2200 UTC.

To Southern Africa, 30 meters 0300-0430 UTC, 20 meters 0030-0530
UTC, 17 meters 2200-0200 UTC, 15 meters 2000-2330 UTC.

To the Caribbean, 80 meters 0330-1000 UTC, 40 meters 0200-1100 UTC,
30 meters 0030-1200 UTC, 20 meters all hours, best 0400-0930 UTC, 17
meters 2130-1400 UTC, 15 meters 1030-0730 UTC (best 0430-0700 UTC),
12 meters possibly around 1300 UTC.

To South America, 80 meters 0330-1030 UTC, 40 meters 0230-1030 UTC,
30 meters 0200-1100 UTC, 20 meters 0000-1230 UTC, 17 meters all
hours, best 0330-1030 UTC, weakest 1600-1930 UTC, 15 meters all
hours, best 0430-0830 UTC, 12 meters 1800-1900 UTC and 0330-0630
UTC.

To Australia, 80 meters 0730-1300 UTC, 40 meters 0700-1330 UTC, 30
meters 0630-1400 UTC, 20 meters 0530-1500 UTC, 17 meters 0330-1000
UTC, 15 meters 0230-0900 UTC, 12 meters 0530-0700 UTC.

To Japan, 80 meters 1030-1200 UTC, 40 meters 0930-1330 UTC, 30
meters 0830-1500 UTC, 20 meters 0600-1730 UTC, 17 meters all hours,
best 0930-1330 UTC, 15 meters possibly 0530-1000 UTC or 1300-1500
UTC.
NNNN
/EX