ARRL

ARRL Propagation Bulletin ARLP014 (2013)

SB PROP @ ARL $ARLP014
ARLP014 Propagation de K7RA

ZCZC AP14
QST de W1AW  
Propagation Forecast Bulletin 14  ARLP014
From Tad Cook, K7RA
Seattle, WA  April 5, 2013
To all radio amateurs 

SB PROP ARL ARLP014
ARLP014 Propagation de K7RA

Solar activity increased over the past week, with average daily
sunspot numbers up 32 points to 81.6, and average daily solar flux
increasing more than 16 points to 113.4. The geomagnetic field was
active on March 29, due to solar wind.

The predicted solar flux is 130 on April 5-7, 125, 115 and 110 on
April 8-10, 105 on April 11-12, 120 on April 13-14, 115 on April 15,
110 on April 16-17, 105 on April 18-19, 100 on April 20-21, 105 on
April 22 and 110 on April 23-24.

The predicted planetary A index is 5 on April 5, 8 on April 6, 5 on
April 7-9, 8 on April 10-12, 5 on April 13-22, then 12, 8, 18 and 15
on April 23-26, 5 on April 27-29, and 8 on April 30 through May 4.

OK1HH predicts the geomagnetic field will be mostly quiet April 5,
quiet to active April 6, quiet to unsettled April 7, mostly quiet
April 8-9, quiet April 10, quiet to unsettled April 11-12, quiet to
active April 13-14, mostly quiet April 15, active to disturbed April
16-17, mostly quiet April 18-19, quiet April 20-22, active to
disturbed April 23, quiet to unsettled April 24, quiet to active
April 25, quiet to unsettled April 26, and mostly quiet April 27.

Our three month moving average of sunspot numbers for January
through March was 80.7. To review recent numbers, the three-month
moving average of sunspot numbers centered on January, 2012 through
February, 2013 were 83.3, 73.7, 71.2, 87.3, 91.5, 96.5, 91.9, 89.9,
81.2, 82.3, 74.4, 82.8, 73.6, and 80.7.

NBC ran an interesting report this week about modeling of the Sun's
interior on a supercomputer. Read it at,
http://science.nbcnews.com/_news/2013/04/04/17603918-suns-magnetic-heartbeat-is-discovered.

Jon Jones, N0JK reports: "I was in Hawaii during the weekend the CME
impact March 17 mentioned by Bill, W3XO occurred. There was no
significant VHF enhancement from the CME and geomagnetic propagation
that day. If anything, conditions seemed worse on 6 meters. The day
before the KH9 Wake Island beacon, H4 and 3D2 were in for hours.

"A day after the geomagnetic field started to settle down,
propagation picked up. On March 22 the KH9/WA2YUN/b was in again for
about 5 hours, and I worked stations in Australia and FK8CP on TEP
around 0545 UTC. I was heard by BV2DQ in Taiwan. The KH9 beacon was
back almost every evening until we left for home on March 23."

Jim Smith, K3RTU sent in another report from the field, working DX
from his backpack-based radio.  He writes, "Last emailed you on
2/25/2013 after working EA8BVP in the Canary Islands, with both of
us running QRP. I had been operating from Ridley Creek State Park in
FM29 (southeast PA). Since then I have made a number of good
contacts from the same location, but yesterday April 3 I hit the
jackpot on 17 meters. From 2045 UTC until 2124 UTC I worked the
following stations using CW: R7AY and SV2JAO, then worked the
following stations using SSB: S57DX, W7FE and IK4GRO. Both R7AY and
SV2JAO gave me 559 reports and got a 5x6 from S57DX, 5x4 from
IK4GRO, but W7FE could barely hear me. I was using my FT-817 and
Buddistick again. To say the least, 17 meters was red hot but not
the weather in FM29. Had to finally pack everything up into my
backpack and head back to the car, which was a mile away, because of
the mid 40s temperature and wind chill that made it feel like 30.
It's hard to send CW when your fingers are stiff from the cold!"

Jim mentioned working W7FE, who is in Henderson, Nevada. Check out
the W7FE page at http://www.qrz.com/db/W7FE to see what's inside the
little building behind his house.

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.

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 March 28 through April 3 were 49, 73, 70, 83,
84, 103, and 109, with a mean of 81.6. 10.7 cm flux was 98.7, 105.1,
108.4, 113.3, 119.1, 122.1, and 127, with a mean of 113.4. Estimated
planetary A indices were 9, 23, 17, 4, 6, 4, and 3, with a mean of
9.4. Estimated mid-latitude A indices were 10, 19, 12, 3, 6, 4, and
3, with a mean of 8.1.
NNNN
/EX