Propagation

[Fansome]

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

[Nella F.]

Is it possible to dumb this down just a tad...

[Pigmeat]

He can't. He doesn't know what it means either.



I thought you fell into Puget Sound?

[Fansome]

It's really quite simple: the main thing to watch for is a spike in the "K-Index". This is known in scientific circles as a "Special K Event", sometimes referred to as a "Kellogg Cycle". When this happens, you can be pretty sure that we are about to experience "extra crunchy" propagation, as we professional DXers refer to it.

It takes time and experience to understand these reports; I'm sure you'll get the hang of it.

He can't. He doesn't know what it means either.



I thought you fell into Puget Sound?

[Jhkayakr]

Well Cheerio then.

[BDM]

LOL...You guys are a riot at times

[Nella F.]

It's really quite simple: the main thing to watch for is a spike in the "K-Index". This is known in scientific circles as a "Special K Event", sometimes referred to as a "Kellogg Cycle".

I remember way back in the day Kelloggs had a "Special K Challenge" an advert. gimic for weight watchers wanting to loose a few. I'd opt for, however, the "Ex-Lax Challenge" for quicker results. 

[redhat]

As I understand it...

A & K, the lower, the better.  High values of either will cause high noise levels and fading.

SFI and sunspots, generally the higher the better.

I use these to gauge whether a particular evening is a good candidate for a show or not.  I also use weather plots to gauge potential storm noise levels, as well as local concerns.

+-RH

[John Poet]

Is it possible to dumb this down just a tad...

Actually, the widget on the right on the FRC home page is kind of a dumb-down version:
http://freeradiocafe.com

It seems to update every few hours along with the propogation forecast updates.

[ChrisSmolinski]

http://spaceweather.com/ has a lot of great propagation info. There's the various indices, as well as graphs.   I find the following useful:

The 5 and 1 minute graphs of x-ray data: http://www.swpc.noaa.gov/rt_plots/xray_5m.html and http://www.swpc.noaa.gov/rt_plots/xray_1m.html show you the x-ray levels measured by satellites. Solar flares, as well as overall solar activity, increases these values. In general, higher levels support propagation on higher frequencies. You want a few days of background levels in the C range for good 10/11 meter propagation, for example. Large increases (M and X level), such as from a solar flare, can cause radio blackouts, usually at lower frequencies.

This graph shows the solar wind and Earth's geomagnetic field: http://www.swpc.noaa.gov/ace/MAG_SWEPAM_24h.html

A solar flare can cause a CME (Coronal Mass Ejection), a burst of charged particles. While the x-rays (from the earlier graphs I mentioned) reach in Earth in minutes, the CME takes a few days to get here. When the CME hits, you will see the solar wind speed (third graph) jump up. Then you may also see the magnetic field values jump around. In general, if the Bz value goes strongly negative, auroral conditions are now possible.

A coronal stream from the Sun can also cause an increase in solar wind, and affect the geomagnetic field. As with a CME, this effects are usually negative, that is they cause poor propagation. Especially at the lower frequencies.

[Nella F.]

thanks for the additional references...printin' 'em up now.

[Fansome]

This page, which is mentioned in the propagation report, has numerous links to various resources for interpreting the numbers:

http://www.arrl.org/propagation-of-rf-signals

[Pigmeat]

With the massive amount of power I ran, I created my own propagation....... a cone of silence around Al Fansome's trailer.