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ARRL Propagation Bulletin ARLP026 (2004)

ARLP026 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 26  ARLP026
From Tad Cook, K7RA
Seattle, WA  June 25, 2004
To all radio amateurs 

ARLP026 Propagation de K7RA

This is Field Day weekend! Conditions don't look bad, although there
is the chance of geomagnetic conditions becoming unsettled.  This
week the sunspot numbers have improved, while geomagnetic conditions
were quiet, which is a great combination. Average daily sunspot
numbers rose over 50 points from last week to 116. Average daily
solar flux was up almost 18 points to 113.7. Sunspot numbers were
the highest on June 20 and 21, Sunday and Monday, and both the
planetary and mid-latitude A indices were very low, in the lower
single digits.

Look at and you can
see the K index at 1 and 0 at all locations for several days.

Sunspot groups 634 and 635 provided most of the activity, and today
they are moving out of view. As a result, predicted sunspot and
solar flux numbers are a bit lower, with the solar flux forecast for
Friday through Monday, June 25-28 at 100, 95, 95 and 90. The
predicted planetary A index for the same four days is currently at
12, 12, 15 and 15. This is due to weak high-speed solar wind from a
recurrent coronal hole coming into view.

K7RA will operate some this weekend, under Class C, which is for
stations in vehicles capable of operating while in motion, and
normally operated in this manner. I'll probably be on 15 and 20
meters, both phone and CW, and 10 meters if it shows any life, and
the operating style will be casual. One of the fun things about the
Field Day operating activity is that the paperwork is very easy.
When submitting a contest entry, you only turn in a list of stations
worked, sorted alphanumerically and divided by band and mode, along
with a summary sheet.

Unlike the ARRL Sweepstakes or DX contests, you will never lose
points for incorrectly copying the exchange from the other station
or the time of the contact because you don't even report it. Only
the call sign is recorded in the appropriate band/mode list. There
are no multipliers for numbers of states or sections worked or for
DX. I'll probably just sort my call sign lists on a laptop with a
simple text editor or word processor while operating, then e-mail in
the results. See for

For this year's Field Day, 20 meters will be your best band, and
possibly 15 as well. 10 meters may be good for some sporadic E skip.
40 and 80 meters should be good after dark. Run some numbers using a
sunspot count of 100 or 105 and a K index of 2 or 3 on W6ELprop to
get some ideas of where openings might point to at different times.
You can download this free at

Sunspot numbers for June 17 through 23 were 106, 118, 90, 142, 139,
113 and 104 with a mean of 116. 10.7 cm flux was 111.3, 107.8,
112.7, 119.1, 115.8, 116.7 and 112.5, with a mean of 113.7.
Estimated planetary A indices were 7, 8, 5, 3, 4, 4 and 5, with a
mean of 5.1. Estimated mid-latitude A indices were 7, 10, 4, 3, 3, 1
and 2, with a mean of 4.3.


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