SB PROP ARL ARLP052

ARLP052 Propagation de K7RA

Geomagnetic conditions were more stable than expected last weekend,

good news for participants in the ARRL 10 Meter Contest. The

planetary A index on Friday through Sunday was 3, 16 and 7 and

mid-latitude A index was just 3, 10 and 5.

Still, there were some scary moments, such as Saturday night in

North America (0035 UTC December 15) when the Australian Space

Forecast Centre issued this alert: "INCREASED GEOMAGNETIC ACTIVITY

EXPECTED DUE TO CORONAL HOLE HIGH SPEED WIND STREAM FOR 15 DECEMBER

2013."

For the reporting week, Thursday through Wednesday, average daily

sunspot numbers rose from 122.1 to 134.4, and average solar flux

went from 162.4 to 159.7, compared to the previous period, December

5-11.

The latest prediction from USAF and NOAA has solar flux at 155, 150

and 145 on December 20-22, 140 on December 23-24, then 130 and 135

on December 25-26, 160 on December 27-28, 165 on December 29-31, 170

on January 1-2, 175 on January 3-6, 170 on January 7, then 165 on

January 8-10, 160 on January 11 and 150 on January 12-13. Solar flux

is expected to decline to a low of 135 on January 18-19, then rise

to 175 at the end of January.

This solar flux prediction for the next seven days was revised

downward significantly from yesterday's forecast in the ARRL Letter.

Wednesday's forecast for December 20-26 was 160, 155, 150, 150, 155,

150 and 155. The latest forecast (Thursday's) shows predicted flux

values of 155, 150, 145, 140, 140, 130 and 135 for those same seven

days. The downward revision was 5 points on December 20-22, 10

points on December 23, 15 points on December 24, and 20 points on

December 25-26.

The predicted planetary A index is 5 on December 20-24, 8 on

December 25-26, then 10 and 8 on December 27-28, 5 on December 29

through January 2, then 10 and 20 on January 3-4, 5 on January 5-9,

then 15 and 7 on January 10-11, then 5 after that until a more

active period around the end of January.

At http://www.swpc.noaa.gov/ftpmenu/forecasts/45DF.html you can get

a daily update of these forecasts, and lately the new one has been

issued between 2119-2123 UTC. But the December 11 forecast came out

at 0755 UTC on December 12, and the December 17 issue at 0051 UTC

December 18. In the past (for years now) I don't recall it ever

coming out as late as into the next UTC day.

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

shorter than usual geomagnetic forecast this week, perhaps for 12

days of Christmas. He sees quiet conditions December 20-24, mostly

quiet December 25, quiet to unsettled December 26, quiet to active

December 27, quiet on December 28, mostly quiet December 29, and

quiet again on December 30-31. Not the same twelve days as

Christmastide or Twelvetide, which actually extend into January, but

I thought it had a nice familiar ring to it.

Operators in the ARRL 10 Meter contest last weekend probably saw the

best conditions for this event in over a decade, and all the reports

sound very happy.

Larry Godek, W0OGH of Gilbert, Arizona did not participate this

year, but did tune around and listen. Larry reports, "It was

wonderfully busy. Signals all over the place and I'd think there

will be a lot of good scores reported. You could sure tell that the

band was good because the activity on other bands and modes was

waaayyyy down! I'm really glad that the band was so good for this

contest."

Jeff Hartley, N8II of Shepherdstown, West Virginia reported:

"Conditions in this year's 10 meter contest were overall markedly

improved from 2012 when the SFI hovered just under 100. Last year I

made less than 10 total European QSOs, this year I worked 150 DLs,

61 Gs (not including the other British countries such as 14 GMs), 58

Is, and 52 Fs.

"The contest started without me, but at 0140Z there were still some

far western USA stations like AZ in and out and some fairly loud

deep South Americans in PY, LU, and CX on TE. The SAs were fairly

hard to work and one other local agreed. The Geminids provided some

good meteor scatter with active periods exceeding one minute and

some stations like K0TT in MN and W0AIH in WI audible almost all of

the time. Meteor scatter was also worked into most of New England

and a few 4s in KY, AL, and GA as well was 0s in MO and IA.

"The EU opening Saturday beat me out of bed with strong signals from

all over EU already in at 1240Z. Russians were not as loud as in Oct

and early November, but I managed to log quite a few in all areas of

Russian EU including UA4 and even two very western UA9s in the log.

Conditions were definitely above seasonal norms and the band stayed

open to OK/OM/9A/S5 probably at least 90 minutes longer than normal

probably due to some EU sporadic-E. Western EU also stayed in much

later than normal, truly exceptional. Throughout the contest

conditions to the south were very good allowing me to easily work

those stations with a Force 12 yagi with 2 el on 10 meters.

Conditions to CA were poor about 95-98 percent of the time when the

band could have been open with best conditions as the band opened

and again well past sunset when it closed. Skip was as short as

ND/SD/KS/TX with CO and the Rocky mountain states being in the sweet

spot for best propagation. AZ was the most active state from here

with 73 QSOs, 2nd was TX with 61, most worked on Sunday. My CO

contacts outnumbered CA 57 to 53, and UT equaled WA with 25.There

must have been some destructive solar wind (OH2XX was loud around

20Z) with a lack of KL7s and a late JA opening Saturday, but once 10

opened the JAs had fairly good signals and there was an amazingly

late secondary opening from about 0110 until past 0130Z when some

big guns could still be worked. I heard NH2T calling someone, but

only worked JA, UA0, and KL7 to the northwest Saturday evening.

Several eastern VKs had good signals and were easy to work thru

small pile-ups.

"Sunday conditions were pretty typical of an average mid winter day

with EU opening about 1235Z, but still some Russians were worked

with good conditions in the 13Z hour. A VU2 also called on CW with a

solid S7 signal. By 1615Z much of EU was gone completely and just

after 1700Z only Iberian peninsula stations (EA/CT) were left.

"Both days the solar activity was high enough to allow many

backscatter QSOs out to the edges of the skip zone, but the weak

spot was in 5 land. I never worked MS, worked LA only once, and a

couple of big gun AR stations were just readable. The best direction

was somewhat dependent on where the target station was beaming, but

south was the better choice until late in the day when SW and W took

over following the Sun. The JAs came in at a normal time around

2230Z with good signals and were fading but workable at 2330Z.

"Other than almost no sporadic-E and the frustration of missing many

west coast stations, conditions could not have been much better. The

highest scoring multi-op stations in the USA made over 3000 QSOs and

D4C had over 4600 with about 3 hours to go. Next year will probably

be way down from this 2nd peak of the cycle, but this current

upsurge was poorly predicted, so we will have to wait and see."

Dan Bates, N5TM of Katy, Texas reported, "Yes, 10 meters was insane.

Friday night was strange with band open until late after dark and

short hops into Colorado and Nebraska. EU was open early both

mornings with strong stations. Good openings the rest of the day to

SA and PNW.

"I could hardly find a clear spot to CQ. Settled in on 28.158 and

had nice runs."

Dan Eskenazi, K7SS of Seattle, Washington reported: "It was really

good! Super fun."

Howard Lester, N7SO of Schuylerville, New York commented, "I had a

lot of fun in the 10 meter contest. With the solar flux as high as

it was, in just maybe three hours over the course of the two days I

worked 27 countries, trying for one of each. Most were in Europe and

South America. My antenna is a 140 foot long inverted-V, so who

knows what directions it favors. The highlight was working club

station WY7SS in the little town of Sundance, Wyoming where, in 1969

during a cross-country trip, I stayed overnight and, at the local

gift shop, bought a leather belt with a longhorn buckle, and an

agate ring. I wish I still had them."

With an identical call sign suffix, Fred Glenn, K9SO of Palatine,

Illinois reported, "I only worked CW, but it was one of the best

'target rich' environments I've ever experienced on 10m. Reminded me

of a busy Field Day on 40 meters with signals all across the band at

maximum density. Both days saw great conditions into Europe and

Northern Africa in the mid morning fading to primarily domestic NA

and Caribbean by mid day and early afternoon. Later, we had big

signals from some of the big guns in ZL and VK land, and also from

Hawaii. Not much participation from those areas, at least on CW, so

the QSO point counts contributed from there were low. Virtually

nothing heard from Japan or South Africa on either day.

"I had put up a temporary dipole just for this event and was

rewarded with 35 new band-countries and a 37 state count with about

7 hours of 'point and shoot' operating.

"Long live the twin peaks!"

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 December 12 through 18 were 156, 141, 163, 158,

114, 91, and 118, with a mean of 134.4. 10.7 cm flux was 164.8,

163.1, 164.2, 156.2, 154.3, 159, and 156, with a mean of 159.7.

Estimated planetary A indices were 3, 3, 16, 7, 7, 3, and 4, with a

mean of 6.1. Estimated mid-latitude A indices were 2, 3, 10, 5, 5,

3, and 3, with a mean of 4.4.

NNNN

/EX