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1994-11-20
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SB PROP @ ARL $ARLP028
ARLP028 Propagation de KT7H
ZCZC AP42
QST de W1AW
Propagation Forecast Bulletin 28 ARLP028
>From Tad Cook, KT7H
Seattle, WA July 16, 1994
To all radio amateurs
SB PROP ARL ARLP028
ARLP028 Propagation de KT7H
The sunspot count was up a bit last week, but the solar flux was
about the same as the week before. The sunspot number is based on
the total area and number of spots visible on the solar surface from
earth. More sunspots of larger areas generally produce more of the
sort of radiation that makes the ionosphere reflective.
Solar flux is energy from the Sun measured here on Earth at 10.7 cm
wavelength, or 2.8 GHz. It correlates fairly closely to the charged
particles reaching the ionosphere that reflect radio waves.
Geomagnetic disturbances were down last week, with a falling A index
in the single digits. But on Thursday, the day this bulletin was
written, the K indices began to rise to four. More active levels
are forecast for the next couple of days due to a recurring coronal
hole, an area on the Sun that generates disturbances here on Earth.
Another period of upset is forecast for July 23 to 28.
Solar flux is expected to stay in the eighties through the rest of
the month. Broad peaks around 90 may appear centered around July 19
and August 6.
Sunspot Numbers from July 7 through 13 were 90, 82, 72, 92, 102, 84
and 81, with a mean of 86.1. 10.7 cm flux was 88.1, 85.8, 85.9, 86,
85.6, 82.9 and 81.4, with a mean of 85.1.
The path projection for this weekend is from Cleveland, Ohio to
Congo.
80 meters should open from 0030 to 0515z, peaking around 0200. 40
meters should be good from 2330 to 0530, and 30 meters from 2230 to
0600. Check 20 meters from 2100 to 0230, and on some days 17 meters
may be open from 0000 to 0200. 15 meters and above do not look good
at this time, but on rare occasions 15 meters may open up after
sundown on the Cleveland end of the path.
NNNN
/EX