SB PROP @ ARL $ARLP037

ARLP037 Propagation de K7RA

ZCZC AP37

QST de W1AW

Propagation Forecast Bulletin 37 ARLP037

From Tad Cook, K7RA

Seattle, WA September 13, 2013

To all radio amateurs

SB PROP ARL ARLP037

ARLP037 Propagation de K7RA

Solar activity was very, very quiet over the past week. For the

reporting period September 5-11, the average daily sunspot number

was only 37.7. Average daily sunspot numbers as reported in this

bulletin have not been nearly this low since Propagation Forecast

Bulletin ARLP024, reporting for June 6-12 of this year, when it was

39.6. The last time it was lower was June 21-27 of last year, when

it was 26.3, as reported in Propagation Forecast Bulletin ARLP026 in

2012.

Australia's IPS Radio and Space Services issued a geomagnetic

disturbance warning at 2330 UTC on September 11. They expect

increased geomagnetic activity due to a high speed solar wind stream

spewing forth from a coronal hole. Coronal holes are magnetic gaps

in our Sun's corona which allow some of the Sun's tremendous energy

to blast out into space. Occasionally some of it reaches our planet,

depending on which way the hole points.

Australia's IPS expects unsettled to active conditions on September

12, with a chance of isolated minor storm levels, unsettled to

active conditions again on September 13, and quiet to unsettled

conditions on September 14.

Predicted planetary A index from NOAA/USAF is 15 and 8 on September

13-14, 5 on September 15-16, 15 and 10 on September 17-18, 15 and 8

on September 19-20, 5 on September 21-25, 10 and 15 on September

26-27, 10 on September 28-29, and 5 on September 30 through October

5.

Predicted solar flux is 95 on September 13, 100 on September 14-17,

105 on September 18-20, 120 on September 21-22, 115 on September

23-30, then 110, 105 and 100 on October 1-3. It then goes to a

minimum of 95 on October 4-5, and rises to a maximum of 120 on

October 18-19.

F.K. Janda, OK1HH of the Czech Propagation Interest Group predicts

geomagnetic conditions will be quiet today on September 13, mostly

quiet September 14, quiet again on September 15-16, quiet to active

September 17, active to disturbed September 18, quiet to unsettled

September 19-21, mostly quiet again on September 22, quiet to active

September 23, quiet again on September 24-25, mostly quiet September

26, active to disturbed September 27, quiet to active September 28,

mostly quiet September 29, quiet again on September 30, quiet to

active October 1, and quiet again on October 2.

A fascinating article appears this weekend concerning reconciliation

of various sunspot records, on the http://HispanicBusiness.com web

site, which might seem a little odd, but of course we welcome good

verifiable information wherever we can find it. Read it at

http://www.hispanicbusiness.com/2013/9/12/spot_of_bother.htm

but note that you may have to click on the URL twice. First time for

me, I saw it redirect to another page on the site, but a second

click goes to the article, "Spot of Bother," by Brian Owens, dated

September 14, 2013.

Another interesting article, this time (yet again) concerning our

Sun's shifting polarity:

http://www.mlive.com/weather/index.ssf/2013/09/the_suns_poles_are_switching_p.html.

Jeff Hartley, N8II wrote on September 11 from West Virginia

(FM19cj): "Back on August 30 there was some Es excitement with

unusual openings into Bear Island, JW9JKA (Svalbard, see

http://dx-world.net/2013/jw9jka-bear-island-svalbard/) on 12 meter

phone at 1823 UTC, then around 2100 UTC S5 (Slovenia) and F (France)

were worked on 12 meter phone as well as EI6JK (59) and DL5RBW (2212

UTC) on 10 meter phone with good signals as well as DL5AXX on

scatter over the South Atlantic and IZ3NYG direct path on 10 CW.

Also logged on 10 meters was EA8YB S9+ on SSB.

"15 meters in the past 10 days has been open well to EU between

about 1300-2000 UTC, sometimes much later and to Asia well after

sunset on good days as well as to Indonesia in our mornings along

with SE Asia.

"12 meters has been in and out to EU with 10 meters mostly only open

to SA and the south Pacific in the evening and late afternoon. On

Sept 5, 12 meters opened well to all of EU except Russia logging YL,

4Z, 9A, S5, EG9 (Ceuta),and DL between 1528-1834 UTC. XW8XZ was

worked on 15 phone earlier at 1336 UTC with an S5 signal.

"HS0 and XW0YJY were loud on 15 phone around 0050 UTC on the

September 8.

"On the September 10, I had a nice run of stations on 12 CW from

1427-1452 UTC including many fairly weak Russians south of Moscow in

the third call area.

"FO/KH0PR has been worked several times on 10 CW making a rare IOTA

tour including today, September 11 at 1846 UTC.

"12 meters seems to open well to EU some days and poorly others when

the SFI is around 100 and K index is low, very difficult to predict.

If the flux jumps up to around 120, 10 meters should come to life."

Note we are only nine days away from the Autumnal Equinox, on

September 22, 2013, at 2044 UTC. As we move from Summer toward Fall,

HF propagation generally improves. For example, if we run a

projection using W6ELprop for two months earlier on August 22 using

a smoothed sunspot number of 100 from Central California to Japan,

10 meters looks marginal from 2130-0130 UTC. But with the same

sunspot number on September 22, conditions look excellent at

2100-0100 UTC and very good from 0100-0300 UTC.

Similarly, on the same dates, from Atlanta, Georgia to Spain on 12

meters on August 22, conditions on 12 meters look fairly good at

1430-2300 UTC. But two months later, signals should be excellent

from 1230-2200 UTC on 12 meters over the same path.

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. More good

information and tutorials on propagation are at http://k9la.us/.

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 September 5 through 11 were 75, 41, 35, 24, 13,

23, and 53, with a mean of 37.7. 10.7 cm flux was 110.1, 101.3,

98.5, 95.7, 94.3, 94.9, and 92.8, with a mean of 98.2. Estimated

planetary A indices were 4, 5, 4, 6, 4, 7, and 6, with a mean of

5.1. Estimated mid-latitude A indices were 3, 5, 4, 6, 4, 6, and 6,

with a mean of 4.9.

NNNN

/EX