ARRL

ARRL Propagation Bulletin ARLP010 (2011)

SB PROP @ ARL $ARLP010
ARLP010 Propagation de K7RA

ZCZC AP10
QST de W1AW  
Propagation Forecast Bulletin 10  ARLP010
From Tad Cook, K7RA
Seattle, WA  March 11, 2011
To all radio amateurs 

SB PROP ARL ARLP010
ARLP010 Propagation de K7RA

Sunspot Cycle 24 continued its upward trend this week.  The average
daily sunspot number was more than double the value of the week
before, rising from 50.9 to 114.  Average daily solar flux rose 44%,
from 96.8 to 139.4.  All this week, through Tuesday, sunspot numbers
and solar flux kept rising and beating old numbers, and we had to
look further and further back into Cycle 23 to find comparable
conditions.

On Tuesday, March 8 the daily sunspot number was 137.  The last time
the daily sunspot number was higher than this was July 7, 2005, when
it was 149.  Twice this week the 10.7 cm receiver at Penticton was
overloaded, swamped by energy from a solar flare, and the daily
solar flux value had to be estimated.  On March 7 and 8 the noon
solar flux readings were 938.6 and 166.7, and they were corrected by
NOAA to estimated values of 153 and 155.  The estimated flux level
of 155 was the highest since July 23, 2004, when the solar flux was
165.

On Thursday, March 10 the sunspot number was 88 and solar flux was
131.3.

Predicted solar flux for March 11-14 is 130, 130, 125, 125, then 120
on March 15-18, 100 on March 19-21 then going below 100 until April
2.  Predicted planetary A index for March 11-13 is 18, 12, and 10,
then 5 on March 14-21, 7 on March 22-23, and 5 on March 24-26, then
7, 7, 19 and 7 on March 27-30.

Geophysical Institute Prague predicts unsettled conditions on March
11-14, quiet to unsettled March 15, and quiet March 16-17.

Last week's report of a South American 2-meter signal heard over
4,700 miles away in North Carolina provoked a number of expressions
of disbelief from some folks very knowledgeable about VHF
propagation.

After exchanging emails with the fellow on the South American end,
I'm not sure what happened.  There are spotting lists showing the
station on 10 meter FM that day instead of 10 meter FM, although our
South American friend says he was on 2 meters at the time the
transmission was heard.  There is also a bit of a language barrier
making some details unclear. One possibility is that the receiver in
North Carolina picked up a 2 meter signal from a downlink from a 10
meter remote base station, some distance away.

A new slightly revised report of recent smoothed sunspot numbers
along with predictions is out this week. Check the Preliminary
Report and Forecast at
http://www.swpc.noaa.gov/weekly/pdf/prf1853.pdf and check page 10.
You can compare this with the last time the same table appeared, at
http://www.swpc.noaa.gov/weekly/pdf/prf1849.pdf and note the
slightly revised smoothed sunspot numbers from August, 2010 through
August 2011.  The numbers are all slightly lower.

Randy Crews, W7TJ of Spokane, Washington posted an exuberant
observation about the recent solar activity. He also wrote, "During
the ARRL SSB Contest, 15 meters was smokin' and I worked the first
European and African Stations on 10 meters since fall of 2004. The
High bands just took on a completely different character. It looks
as if this is the end of our long drought on the High Bands. W1ZR
could not have better timed his article in March's QST regarding
being ready for the expected surge."

Jaap Verheul, PA3DTR wrote to us from Zaltbommel, Netherlands about
recent conditions:  "I experienced good conditions now for about 5
days in a row, no wonder: now the solar flux is up and sunspots
1164, 1165, and 1166 are on the solar disk!

"I had much fun in the ARRL contest last weekend. 15 meters was a
thrill to work USA stations. But that isn't all. I even found 17
meters open to the USA after dark on Monday evening! I worked W1GUE
with 100 watts and a dipole on CW.  That has not happened for a long
time.

"I am very interested in propagation on 30 meters and I often check
this website: http://www.spacew.com/www/realtime.php. It shows a
recent high-resolution map of Maximum Usable Frequencies (MUFs) for
3,000 kilometer radio signal paths. Today I found out that there is
no contour present anymore for 10 MHz in the northern hemisphere.
That doesn't mean that the band is all-open, but from my location
the chances of propagation paths over 3,000 kilometers is much
better thanks to the new solar cycle and springtime conditions
(equinox)."

I think instead of reflecting actual current MUF, the map is based
on the latest predicted smoothed sunspot number for the month, which
is currently 43.

John Shew, N4QQ of Silver Spring, Maryland reported excellent
conditions during the ARRL SSB DX Contest last weekend on 10 meters.
He wrote, "While CQing on 10 meters from W3LPL's superb multi-op
contest station Sunday morning with the beam pointed SE around 1250z
to attract PYs and other South Americans, I was answered in quick
succession by JA6WJL, JA6WIF, and BV1EK, -- all S9 signals on the
long path. Another 10 minutes of CQs attracted no other long path
stations, but a check of DX putouts indicate that the band was open
long path until around 1330z."

You can get a nice view of the W3LPL antenna array by clicking on
http://snurl.com/26zqr4.  Click on "Bird's Eye" to get a detailed
view, zoom in, and click on the compass to see images from different
perspectives.  You can also expand the image to the left by clicking
on the left-arrow on the upper left corner of the picture.

Roger Harrison, VK2ZRH of Woollahra, New South Wales, Australia
noted the N4QQ comments recently about trans-equatorial propagation.
He wrote, "For the benefit of newcomers to TEP, I have two web pages
that each give a detailed introduction to afternoon and evening type
TEP, written over 2006-2007 and posted in 2007. You'll find them
here:

Afternoon TEP:
http://home.iprimus.com.au/toddemslie/aTEP-Harrison.htm

Evening TEP: http://home.iprimus.com.au/toddemslie/eTEP-Harrison.htm

"Also, the Australian IPS Radio  Space Services has a PDF on TEP
here:
http://www.ips.gov.au/Category/Educational/Other%20Topics/Radio%20Communication/Transequatorial.pdf

"During the 1970s, I worked for 7 years at IPS Radio and Space
Services. I was employed in the Low Latitude Research Section for
part of that time, working for Dr Leo McNamara (author of 'Radio
Amateurs Guide to the Ionosphere') on TEP. I also pursued my
interest in sporadic E, with the aid and encouragement of IPS
colleagues."

Pat Dyer, WA5IYX of San Antonio, Texas wrote: "March 3 I heard my
first LU on 6 meters since Aug 2005 (was an Es link to F2 the
weekend that Hurricane Katrina hit New Orleans). The 5w LU7YS beacon
on 50.085 MHz was about 539 at 2215z.  The LU7YS op himself made
some TX and XE2 QSOs, but his CW signal had too much QSB on it here
for me to try a call.

"March 2 we had a lot of midday-early afternoon 6 meter Es to the
southeast, and there had been hope that would link into the F2
that's been creeping ever closer recently (YS, XE1) as the rising
solar flux and season get more favorable.  A rule-of-thumb here has
been solar flux of 120-130 is a good level for 6 meter LUs in
March-April.  There was no direct evidence of any Es involved in the
March 3 event, though there IS a lot of water in that direction for
a linking hop to land in.  March is statistically the worst month of
the year for VHF Es here so that linkage is far more common in April
as that season awakens.

"Now, one of my pet peeves regarding the liberal use of TE/TEP to
describe these modes:  Our daytime 6 meter paths to LU are usually
the result of a chordal F2 hop (no 1-hop ground reflection), exhibit
normal QSB, and are designated F2F2 (vs. F2-F2).  The after-dark
('classical TE') is caused by a scatter mechanism in the F2 layer
and is distinctive in its multi-path and flutter sound.  One only
has to hear the same-path stations by each mode to appreciate the
difference.  (Much pioneer work on this was done in Cycle 19 with
ZE2JV documenting it in QST articles.)"

Bob Karpinski, WB8B of Clinton Township, Michigan sent in a report
about using low power on 12 and 17 meters: "With the solar flux
reaching 135, 12 meter propagation was unprecedented on March 6 with
a lot of DX activity and big signals. The band was already opening
into EU and AF around 1200z while ending with nice openings across
the Pacific and into Japan.

"Propagation was so exceptional on 12 meter CW that 11 DXCC
countries were worked using 1 watt of output power and (3) active
elements on a Mosley PRO67 yagi at 63 ft. The 1 watt QRPp contacts
included M0DHO (Great Britain), LA0DX (Norway), VO1HP (Canada),
PA1CC (Netherlands), 4Z4DX (Israel), G3RXP (Great Britain), GM3YTS
(Scotland), SV1CQN (Greece), GW3YDX (Wales) , EI6IZ (Ireland),
MI0BPB (Northern Ireland) and 6W2SC (Senegal). Additional 12 meter
CW contacts were made with SV2BOH (Greece), CO8LY (Cuba) and PA3DTR
(Netherlands) at the 5 watt level.

"Also, 17 meters has been providing excellent evening paths into the
northwest, especially on March 6, when I logged a CW QSO with KL7J
in Alaska using 1 watt QRPp around 2300z. His signal was a very
solid S9+30dB which ended my Sunday of contacts with 12 DXCC
countries using 1 watt of output power."

Thanks, Bob!

Mike Treister, W9NY reported: "Operating W9NY from Dune Acres
Indiana this weekend, I was absolutely astounded by the band
conditions on 15 meters (I only worked 15 meters for the ARRL SSB
contest). It was like the good old days. Signals from Europe were
often coming in 20 over 9, as were many from Japan. While running
about 100 JAs late Saturday afternoon with my TH7 aimed in that
direction I kept having stations call me from Europe and South
America off the side and back of the beam! I worked several European
and Japanese stations who were running only 5-10 watts (one British
station was running 3 watts), and they were all coming in Q5. I
received numerous signal reports that I was well over the customary
5 by 9. I slept Saturday night and got up at 6 AM Sunday to see what
was happening on 15, and was surprised to find the entire phone band
packed with DX stations. This was the most fun that I have had
during a contest in many years.

"With the solar flux reaching 135, 12 meter propagation was
unprecedented on 3/6 with allot of DX activity and big signals. The
band was already opening into EU and AF around 1200z and while
ending with nice openings across the Pacific and into Japan.

"Propagation was so exceptional on 12 meter CW that 11 DXCC
countries were worked using 1 watt of output power and (3) active
elements on a Mosley PRO67 yagi at 63 ft. The 1 watt QRPp contacts
included M0DHO (Great Britain), LA0DX (Norway), VO1HP (Canada),
PA1CC (Netherlands), 4Z4DX (Israel), G3RXP (Great Britain), GM3YTS
(Scotland), SV1CQN (Greece), GW3YDX (Wales) , EI6IZ (Ireland),
MI0BPB (Northern Ireland) and 6W2SC (Senegal). Additional 12 meter
CW contacts were made with SV2BOH (Greece), CO8LY (Cuba) and PA3DTR
(Netherlands) at the 5 watt level.

"Also, 17 meters has been providing excellent evening paths into the
N.W., especially on 3/6, when I logged a CW QSO with KL7J in Alaska
using 1 watt QRPp around 2300z. His signal was a very solid S9+30dB
which ended my Sunday of contacts with 12 DXCC countries using 1
watt of output power."

Max White, M0VNG of Worcester, UK sent an interesting article from
NASA about some early history of sunspot observation.  Read it at
http://www.nasa.gov/mission_pages/sunearth/news/400yrs-spots.html.

Tim Goeppinger, K6GEP of Orange, California alerted us to a series
of comics published this week that feature solar activity.  From
March 7-10 the comic strip "Brewster Rockit"
(http://www.gocomics.com/brewsterrockit/2011/03/07/) is running the
series.

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://mysite.ncnetwork.net/k9la/index.html.

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 3 through 9 were 71, 104, 114, 118, 122,
137, and 132, with a mean of 114. 10.7 cm flux was 120.9, 126.8,
134.6, 142.5, 153, 155, and 143.1, with a mean of 139.4. Estimated
planetary A indices were 12, 10, 5, 5, 10, 5, and 4, with a mean of
7.3. Estimated mid-latitude A indices were 11, 7, 4, 3, 7, 4, and 2,
with a mean of 5.4.
NNNN
/EX