ARRL

ARRL Propagation Bulletin ARLP042 (2000)

SB PROP @ ARL $ARLP042
ARLP042 Propagation de K7VVV

ZCZC AP42
QST de W1AW  
Propagation Forecast Bulletin 42  ARLP042
From Tad Cook, K7VVV
Seattle, WA  October 20, 2000
To all radio amateurs 

SB PROP ARL ARLP042
ARLP042 Propagation de K7VVV

The rise in solar flux for that was predicted this week in last
week's Propagation Forecast Bulletin ARLP041 did not happen. Last
week's bulletin stated that by October 18 and 19 we should see a
short term peak in solar flux around 220. Instead, solar flux rose
slightly over the weekend, then dropped below 160, and on October 18
and 19 it was 151.1 and 157.8. These short range predictions are
based upon the previous solar rotation, plus what sunspot regions
can be seen rotating toward the center of the solar disk, as well as
a bet placed upon whether the activity in each region is increasing
or decreasing.

The current outlook is for a slowly and modestly rising solar flux,
with the values for Friday through Monday at 160, 160, 165 and 170.
The latest best guess is for solar flux to peak for the short term
at only 190 on October 29 and 30, then decline to 145 around
November 5.

Geomagnetic conditions are expected to remain fairly stable on
Friday and Saturday, but planetary A index my rise to 20 and 25 on
Sunday and Monday. Geomagnetic indices are expected to calm down
after that, but become unsettled to active around October 30 through
November 1.

It has been some time since Propagation Forecast Bulletin ARLP032 on
August 11 when we last presented a path projection. This weekend we
have two. One is for the VK/ZL Oceania CW Contest, and the other is
for the RSGB 21/28 MHz CW Contest. The points of origin for each
path will be pretty general, one for the center of the continental
U.S.A, one for the East Coast, the other for the West Coast. The
solar flux value used will be 160, which represents an average of
values over ten days, including the projected values for October 20
and 21. The date used for the prediction is October 21.

To Australia from the West Coast, USA, 80 meters 0900-1500z (best
1200-1330z), 40 meters 0830-1530z (best 1000-1400z), 20 meters
0700-1700z (best 0900-1430z), 15 meters 0400-0500z and 2000-2100z,
10 meters possibly 2200-0300z. To New Zealand, 80 meters 0700-1430z
(best 0930-1330z), 40 meters 0530-1500z (best 0730-1400z), 20 meters
0430-1600z (best 0700-1400z), 15 meters 0100-1000z (stronger later
during the period), 10 meters 1900-0400z.

To Australia from the center of the USA, 80 meters 0900-1330z, 40
meters 0830-1400z, 20 meters 0800-1500z, 15 meters possibly around
1500z, 10 meters possibly around 2230-0030z. To New Zealand, 80
meters 0630-1300z, 40 meters 0600-1330z, 20 meters 0430-1500z, 15
meters 0200-0300z, 10 meters possibly 1000-0100z.

To Australia from the East Coast, USA, 80 meters 0900-1200z, 40
meters 0830-1230z, 20 meters 1200-1400z, 15 meters 1400-1500z, 10
meters possibly 2130-2300z. To New Zealand, 80 meters 0630-1200z, 40
meters 0530-1200z, 20 meters 0430-1330z, 15 meters 0100-0200z, 10
meters possibly 1930-2330z.

To England from the West Coast, USA, 15 meters 1600-1900z, 10 meters
possibly around 1730z. To England from the center of the USA, 15
meters 1400-2000z, 10 meters 1600-1800z. From the East Coast, 15
meters 1300-1930z, 10 meters 1530-1730z.

Sunspot numbers for October 12 through 18 were 187, 167, 157, 99,
109, 130 and 128 with a mean of 139.6. 10.7 cm flux was 162.7,
168.1, 163.3, 161.1, 160.9, 154.1 and 151.1, with a mean of 160.2,
and estimated planetary A indices were 8, 27, 42, 8, 8, 9 and 8 with
a mean of 15.7.
NNNN
/EX