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ARRL Propagation Bulletin ARLP034 (2005)

ARLP034 Propagation de K9LA

QST de W1AW  
Propagation Forecast Bulletin 34  ARLP034
From Carl Luetzelschwab, K9LA
Fort Wayne, IN  August 12, 2005
To all radio amateurs 

ARLP034 Propagation de K9LA

Carl Luetzelschwab, K9LA, is filling in for Tad Cook, K7RA, this
week.  This report covers the period Friday, August 5 through
Thursday, August 11, with a 3-day outlook for August 12-14.

Solar activity was low to very low during the reporting period, with
the biggest flare being a C2.8 on the first day.

Geophysical activity ranged from quiet (Friday, Monday, Tuesday, and
Thursday) to minor storm (Saturday, Sunday, and Wednesday).

Very low solar activity and quiet to unsettled geophysical activity
are predicted for the next three days.

There have been several 50 MHz spots on PacketCluster during this
reporting period.  These spots reminded this reporter of an old plot
of sporadic E probability versus month and time of day.  The web
version of this bulletin includes this plot.  Although the data is
from 1957 and 1958, it should still offer a good guideline for the
probability of sporadic E occurrences.  This plot comes from one of
the old geophysics handbooks published by the USAF.  Note that we
are moving away from the high probability months for sporadic E.

Some of the more interesting DX scheduled to be on this weekend
includes PY0F, TK, 5X, HB0, P5, HS, and TY.  Thanks to The Daily DX
and QRZ DX.  The best bands for working these stations should be 40,
30, 20, and 17 meters.  Use your favorite propagation prediction
software to determine the best times of day.

Operating events this weekend include the WAE (Worked All Europe) DX
contest (CW) and the Maryland-DC QSO party.  It is likely that 20
and 40 meters, and to some extent 80 meters for the Maryland-DC QSO
Party, will be the workhorse bands for these two events.

For more information concerning radio propagation and an explanation
of the numbers used in this bulletin see the ARRL Technical
Information Service propagation page at,  An archive of past
bulletins is found at,

Sunspot numbers for August 4 through 10 were 85, 74, 54, 67, 56, 51
and 34 with a mean of 60.1.  10.7 cm flux was 106.1, 98.8, 93.4,
92.3, 86.4, 82.5 and 76.3, with a mean of 90.8.  Estimated planetary
A indices were 14, 9, 34, 18, 8, 10 and 22 with a mean of 16.4.
Estimated mid-latitude A indices were 9, 6, 25, 12, 6, 8 and 9, with
a mean of 10.7.


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