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ARRL Propagation Bulletin ARLP028 (1999)

ARLP028 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 28  ARLP028
From Tad Cook, K7VVV
Seattle, WA  July 9, 1999
To all radio amateurs 

ARLP028 Propagation de K7VVV

Average solar flux and sunspot numbers were down this week compared
to last, but this is not surprising considering last week's high
numbers.  Average sunspot number dropped from 272 to 204, and
average solar flux was down nearly 18 points to 180.8.  Active
geomagnetic days were Friday and Saturday when the planetary A index
was 26 and 13.

The forecast for the next three days, Friday through Sunday, is a
solar flux of 140, 140 and 135 and planetary A index of seven for
all three days.  Beyond this weekend look for a declining solar flux
to continue around 135 until July 14, then go above 170 after July
19.  One forecast earlier this week from the NOAA Space Environment
Service Center has solar flux peaking around 200 from July 22
through 27, but a later more conservative projection suggests a peak
above 180 from July 24-26.

Under current summer conditions, the 160 and 80 meter bands are
noisy because of seasonal atmospherics in the northern hemisphere,
while 20 meters is open late into the evening.  Conditions on 10 and
12 meters will tend to get better for long distance communications
as the days get shorter and we progress toward the fall equinox.

In VHF news, a number of west coast stations have been reporting
signals from Hawaii via tropospheric ducting.  Check the KH6FOO web
page at for reports on this
propagation mode, and click on the Post Ducting Report button to see
the latest information.

N0LL in Kansas sent an impressive list of stations worked via 2
meter E-skip during a one hour Field Day opening, all in southeast
states. He also worked an impressive number of stations around the
east coast and southeast states via E-skip on July 5-7, as well as a
6 meter contact with KL7FZ on July 3.

Sunspot numbers for July 1 through 7 were 236, 232, 213, 211, 188,
190 and 158 with a mean of 204.  10.7 cm flux was 195.4, 187.1,
196.8, 185.6, 174.2, 167.9 and 158.4, with a mean of 180.8, and
estimated planetary A indices were 9, 26, 13, 4, 4, 9 and 5, with a
mean of 10.

The path projections for this week are from an area in Alaska
between Fairbanks and Anchorage.

To Europe, 30 meters 0430-0600z, 20 meters great at all hours,
peaking 0130-0430z, 17 meters 1730-0100z and 0600-0730z.

To Southern Africa, 20 meters weakly from 2130-0100z, 17 meters

To the Caribbean, 80 meters 0600-0930z, 40 meters 0400-1000z, 30
meters 0230-1030z, 20 meters 0000-1230z, 17 meters 1500- 0900z, 15
meters possibly 1830-0200z.

To the center of the continental USA, 80 meters 0530-1130z, 40
meters 0230-1300z (peaking 0800-1000z), 30 meters 0100-1430z (best
0700-1000z), 20 meters all hours, best 0600-1100z, 17 meters
possibly 1730-0730z.

To South America, 80 meters 0600-1000z, 40 meters 0500-1030z, 30
meters 0400-1100z, 20 meters 0100-1200z, 17 meters 2230- 1330z, 15
meters 2100-0230z and 0530-0630z.

To Australia, 80 meters 0930-1330z, 40 meters 0900-1500z, 30 meters
0830-1600z, 20 meters 0700-1700z, 17 meters 0600-1330z, 15 meters
0730-1000z and 2200-2300z.

To Japan, 80 meters 1030-1430z, 40 meters 0930-1700z, 30 meters
0730-1900z, 20 meters all hours, best 1100-1400z, weakest


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