ARRL

ARRL Propagation Bulletin ARLP042 (2012)

SB PROP @ ARL $ARLP042
ARLP042 Propagation de K7RA

ZCZC AP43
QST de W1AW  
Propagation Forecast Bulletin 42  ARLP042
From Tad Cook, K7RA
Seattle, WA  October 19, 2012
To all radio amateurs 

SB PROP ARL ARLP042
ARLP042 Propagation de K7RA

Sunspot activity rose this week, with average daily sunspot numbers
up over 45 points to 97, and average daily solar flux rising over 24
points to 129.2. October 12-14 had high geomagnetic activity, with a
planetary A index at 12, 38 and 19, college A index (in Alaska) at
18, 70 and 33, and mid-latitude A index (measured in Virginia) at
12, 28 and 20. On October 13 solar wind spilled through a gap in our
Earth's magnetosphere, unsettling conditions here. Aurora was seen
across the northern tier states in the United States.

The latest prediction is for solar flux peaking at 140 (not at 150
as predicted until October 12, and not 135 as reported in the ARRL
Letter for October 18) for October 19-21, 135 and 130 on October
22-23, 125 on October 24-26, 130 on October 27-28, then 125, 120,
115, 110, 105 and 100 on October 29 through November 3, and 105 on
November 4-5, peaking again at 140 on November 12-14.

The predicted planetary A index is 6 on October 19, 5 and 8 on
October 20-21, 5 on October 22 through November 7, then 10, 20, 15,
12, 8, 8, 10 and 8 on November 8-15, and 5 on November 16 through
the end of November and the first few days of December.

OK1HH predicts the geomagnetic field will be quiet October 19-22,
mostly quiet October 23-24, quiet October 25-26, quiet to active
October 27, active to disturbed October 28, quiet October 29, quiet
to unsettled October 30, quiet October 31, mostly quiet November 1,
quiet to unsettled November 2, mostly quiet November 3, active to
disturbed November 4-5, quiet to active November 6, quiet to
unsettled November 7-8, quiet to active November 9, and active to
disturbed November 10.

Recently I've made a spreadsheet for myself to track changes in the
45-day solar flux forecast. This is an interesting exercise in
observing the changes to the forecast over time. Dates along the
vertical access are the dates of each of the forecasts, and along
the horizontal are the dates that each of the values correspond to.
Each cell has a flux value.

So looking at October 13, 2012, tracking the changes to the flux
values for that date from September 27 to October 12, we see it
start out at 115 in the October 13 column on September 27, then
change to 105 on October 6, then 100 on October 7-9, 115 on October
10-11, 125 on October 12, then on October 13 the actual value is
recorded, 124.9. We end up with smoothly changing groups of flux
values, finally ending at the real number on the bottom. The
spreadsheet keeps progressing from upper left toward lower right. As
these are 45-day forecasts, the series of numbers is always 45 days
wide.

In last week's Propagation Forecast Bulletin ARLP041 we mentioned
John King, EI2HVB of Letterkenny, Ireland. This week he gave a
little more detail. He worked W1AW at 1927 UTC on October 10 on 20
meter CW running two watts with an MFJ Cub 9320.

This week he wrote: "I have a sloping 'V' dipole, the front plane of
which is firing due east, and best DX to the east so far is a 559
into Perm in eastern Russia (2000 miles from my QTH). I regularly
get 579 to 599 all over Eastern Europe. I cannot seem to work Spain,
Portugal or North Africa, so there is no side lobe to the south of
my antenna. However, there seems to be a side lobe firing north, as
I recently got a 589 into Iceland. On October 10 when I worked W1AW
the Northern Lights were seen from the north of Ireland later that
night, and had also been visible the previous night. I suspect my
signal was going over the North Pole rather than across the
Atlantic."

Of course without a directional antenna, it is difficult to know,
although we can assume W1AW was using a directional antenna from
their end. Following last week's bulletin, Jim Parkinson, W9JEF of
Tontitown, Arkansas commented: "When we talk about radio
propagation, most of us assume the path to be a straight line (in
azimuth). But according to KL7AJ, in QST articles, that path is not
always 'straight' (not that there's anything wrong with that).

"As Eric points out - and many other hams such as myself have
experienced - the aurora and other polar effects can bend or reflect
a signal. Assuming that the 'straight' path did not exist at the
time, would the portion of signal from John's dipole that reached
the aurora region not have been bent back eastward toward W1AW (with
reciprocity)?"

By the way, a little point of interest, Jim's aunt Ethelyn Parkinson
wrote the 1968 book, "Today I Am a Ham."

John Jones, N0JK wrote: "There was a nice 'off season' October Es
opening on 50 MHz Sunday October 14. The band appeared to be open
over 6 hours for many across the eastern USA to the Midwest and
southern Canada.

"Here in Kansas, the W3HH/b EL89 (3.25 W, omni antenna) and the
W4CHA/b EL88 6 meter beacons were solid copy on my attic dipole
around 0315 UTC Oct. 15."

Joe Dawson, K4WLS of Atlanta, Georgia wrote on October 18: "I have
made contacts in France, Belgium, Latvia, Greece, Croatia, Morocco,
Mexico, Cuba, Cayman Islands and Italy in the past 3 days during my
lunch hour using a slinky antenna and 50 watts on 10 meters. Similar
DX activity on 15 and 17 meters as well, but not to the extent of 10
meters. The barn door is open on 10 meters during the day but shuts
down cold around 5pm eastern."

Thanks Joe!  And thanks for mentioning the slinky antenna, which I
have not heard of for a long time. A web search though shows there
is still quite a bit of interest in this antenna.

If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at,
http://arrl.org/propagation-of-rf-signals. For an explanation of the
numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past
propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation. Find more good
information and tutorials on propagation at
http://myplace.frontier.com/~k9la/.

Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.

Sunspot numbers for October 11 through 17 were 82, 89, 85, 97, 119,
107, and 100, with a mean of 97. 10.7 cm flux was 116.6, 121.9,
124.9, 132.1, 136.8, 137, and 135, with a mean of 129.2. Estimated
planetary A indices were 6, 12, 38, 19, 8, 5, and 7, with a mean of
13.6. Estimated mid-latitude A indices were 5, 12, 28, 20, 7, 5, and
6, with a mean of 11.9.
NNNN
/EX