ARRL Propagation Bulletin ARLP042 (2007)

ARLP042 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 42  ARLP042
From Tad Cook, K7RA
Seattle, WA  October 12, 2007
To all radio amateurs 

ARLP042 Propagation de K7RA

The average sunspot number for the past week is about half what it
was the week before, but this doesn't mean much, since only two days
of the last seven had any sunspots.  In fact, on only 7 out of the
last 29 days did the sun show any spots.

Geomagnetic indices (the A and K index) have been very quiet lately.
The US Air Force predicts the planetary A index to stay around five,
which is very quiet, for October 12-16.  October 26 is the next time
they predict active conditions, with a planetary A index of 25.
Since October 6 the planetary A index has been below five.

Geophysical Institute Prague predicts quiet to unsettled conditions
for today, October 12, quiet conditions on October 13-16, and
unsettled conditions October 17-18.  I suspect we won't see sunspots
any time soon, although this can change.  It seems we are still in
the bottom of the cycle.

The two days we saw a sunspot last week were Saturday and Sunday,
October 6-7, with sunspot numbers of 15 and 13.  Bill Paul, KD6JUI
of San Mateo, California was operating portable with a G5RV and 100
watts for the California QSO party, and had a several hour opening
on 15 meters on Saturday.  He didn't say where to, but I assume 15
opened toward the East Coast and Midwest.  Not a peep out of 10
meters, and 15 was more productive for Bill than any other band.

Randy Leedy, WS4C of Greenville, South Carolina was QRT for 8 years,
but returned to the air about 13 months ago, and hasn't let any lack
of sunspots discourage him.  He offers yet another 3B7C report: with
700 mW on September 19 at 1154z on 30 meters into a 35 foot high
inverted V, and his "location is down in a low spot."  In the past
13 months he has worked 188 countries, with 101 on 5 watts or less
and 70 at 1 watt or less.  His DXCC Challenge total in that period
is 690.  His biggest disappointment is not hearing BS7H well enough
to work them.

Floyd Chowning, K5LA points out that activity on
is on the rise, and to check out current 30 meter records on that
site.  It shows many stations active, and anyone can download the
software from the PropNET web site to join in this interesting
automated propagation tracking system.

Larry McKay, K5MK of Jackson, Mississippi just got a new PC, and
like almost every new PC, it came with Microsoft Vista.  But Larry
was disappointed to find that he couldn't use W6ELprop, the popular
freeware propagation prediction program.  He says it won't run,
although the author, Shel Shallon, W6EL, says he has heard that it
works with Vista.  Shel is running Windows XP, and has no plans to
install Vista or update his free software for Vista.

Has anyone had problems with W6ELprop and Vista, and then discovered
a work-around?  Larry didn't give much detail, except to say that it
wouldn't run.  You can download the program from and try it yourself.

Finally, this has nothing to do with propagation, but George
Copeland, W7ZVD of Walla Walla, Washington sent a link to an amusing
short film about ham radio produced nearly 70 years ago:  Look up the film
credits at, and note the part of
the ship's radio operator was played by Clayton Moore, who later was
the Lone Ranger.

If you would like to make a comment or have a tip for our readers,
email the author at,

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at, For a detailed
explanation of the numbers used in this bulletin see,  An archive of past
propagation bulletins is at, Monthly
propagation charts between four USA regions and twelve overseas
locations are at,

Sunspot numbers for October 4 through 10 were 0, 0, 15, 13, 0, 0 and
0 with a mean of 4.  10.7 cm flux was 67.3, 67.8, 69, 68.1, 68.1,
68.7, and 68.1 with a mean of 68.2.  Estimated planetary A indices
were 10, 7, 5, 4, 3, 3 and 3 with a mean of 5.  Estimated
mid-latitude A indices were 8, 5, 3, 1, 0, 0 and 1, with a mean of