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Propagation Forecast Bulletin #04 de K7RA:

from W1AW Bulletin via the ARRL on January 25, 2013
Website: http://www.arrl.org/
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Propagation Forecast Bulletin #04 de K7RA:

ZCZC AP04
QST de W1AW
Propagation Forecast Bulletin 4 ARLP004
>From Tad Cook, K7RA
Seattle, WA January 25, 2013
To all radio amateurs

SB PROP ARL ARLP004
ARLP004 Propagation de K7RA

Average daily sunspot numbers over the past week were less than half the value for the previous week, dropping nearly 73 points to 56.4. Average daily solar flux declined as well, nearly 47 points to 110.7. Average geomagnetic indices were up about 50%, but still very quiet. The higher average was due to events on January 17, when the planetary A index was 13, higher than recent measures, but still moderate. The cause of the mild disturbance was the arrival of a CME, or Coronal Mass Ejection.

Predicted solar flux from the January 24 forecast from NOAA and USAF has 10.7 cm flux values at 100 on January 25-26, 95 on January 27-30, 100 on January 31 through February 1, 110 on February 2, 120 on February 3-4, 125 on February 5-8, 120 on February 9-14, 115 and 110 on February 15-16, and 105 on February 17-18.

It doesn't look like a return to solar flux values around 170 (where it was on January 9-12) is expected any time soon. But those high levels earlier in the month weren't predicted either.

Looking back, a flux reading of 135 was predicted for January 9 in the November 25 through December 9 daily forecasts, then downgraded to 110 on December 10-16, then increased to 115 on December 17-30, downgraded to 105 on December 31 through January 2, increased to 115 on January 3, 135 on January 4, 130 on January 5-6, 145 on January 7, and 150 on January 8. The final result? 169.3 on January 9, far above any predictions over the previous 45 days, which were revised eight times.

The forecasts are issued daily, usually after 2100 UTC and posted at http://www.swpc.noaa.gov/ftpmenu/forecasts/45DF.html.

The predicted planetary A index from the same January 24 forecast is 8, 15, 20 and 12 on January 25-28, 5 on January 29 through February 8, 8 on February 9-10, 5 on February 11-18 and 8 on February 19. The January 25-28 levels are higher then predicted a day earlier, on January 23. In that earlier forecast, planetary A index for those same four days was 8, 8, 5 and 5.

F.K. Janda, OK1HH of the Czech Republic expects the geomagnetic field will be quiet to unsettled on January 25-26, quiet January 27-28, mostly quiet January 29, quiet on January 30-31, mostly quiet February 1-2, quiet on February 3, mostly quiet February 4, quiet on February 5-6, quiet to unsettled February 7-8, quiet to active February 9-10, mostly quiet February 11-12, quiet to active February 13-14, active to disturbed on February 15, and quiet to unsettled February 16.

Jeff Hartley, N8II of Shepherdstown, West Virginia wrote, "It has been a pretty boring winter for DX. I did work four VK3s in a row from 2225-2255Z including one mobile who was S6 and a QRP 5 W to 1/2 wave vertical who was S5 with QSB on 20M SSB long path Thursday (January 24), so that path was very good. 12 and 10 seemed dead at that time and only South America was heard on 15. No European signals were heard on 160 around then and again at 0050Z (nothing on 80 also at 0050Z). But, if the K stays low, the lower flux should help the CQWW 160 contest this weekend."

Unfortunately, the forecast for this weekend has some geomagnetic activity, with the planetary A index on February 25-27 at 8, 15 and 20.

The 160 meter contest Jeff referred to is the CW weekend of the CQ World Wide 160-Meter Contest. The contest page at http://www.cq160.com/ says it runs from 2200 GMT today (Friday, January 25) to 2200 GMT Sunday. By the way, 2200 GMT (Greenwich Mean Time) for our purposes is the same as 2200Z or 2200 UTC. On the West Coast, this is long before sunset, at 2:00 PM PST.

On January 19, Jeff wrote: "Friday morning January 18 I had a chance to operate and had some very strong signals on 10 phone from the UK with small stations mostly S7-9. Even 5 and 10 watt stations were good copy. This was starting about 1330Z and the EU opening ended after 1600Z. Countries worked in EU started with SP, DL, EI, G, GM then later PA, ON, F and the DLs were about the only ones left at 1610Z. Friday evening was noticeably better than all this past week, but did not get to the radio until 0040Z. At that time 15 was in good shape to JA with the loudest, JH1GEX S9. BW2AK was heard and 9V1YC who was about S3-4 was worked easily thru a pile up. 15 was still open to JA at 0115Z, normally by 24Z, 15 seems closed to everywhere. 17 was also quite good into JA around 0100-0130Z with JA9YYY S9 on SSB.

The HA DX contest started at 12Z Saturday with lots of EU and Russian activity. Russians are usually only easy to work very early in the day on 20 and about nil on 15 and higher. At 1315Z when I started thru 1430Z, Russians had good signals on 20 CW but there was deep rapid QSB making copying dits and sometimes whole letters/numbers very difficult. I worked about three Ural mountain area UA9s and found UN2E about S3 plus quite a few from UA3, about four from UA4 and some loud ones near St Petersburg from UA1. The deep QSB was even a problem on signals as close as Germany as well as the Hungarians. YE1ZAT called in around 1545Z with a good signal. 15 was open pretty well to EU, but 10 was barely open at all to very southern EU, I heard T77BL working AA3B.

"In the afternoon, I briefly operated in the NAQP phone contest before heading off to work. At 1835-1900Z, 10M had a good number of loud signals with one VE6 hitting 30 dB over S9. Many UT stations were worked along with stations from CO, AZ, WA, ID, MT and NM; only W6TA and K6LA who was weak were worked in CA. 15 was wide open to TX and was a bit of a struggle to work west coast stations with Midwest stations beating me out consistently."

In a January 18 email titled "Outstanding 160M propagation Jan 11-12 in Ohio," Robert Elek, W3HKK of Johnstown, Ohio wrote: "Worked more Europeans than ever around their sunrise on Jan 11 and 12, plus KL7 and VP2 earlier in the night. Huge signals! Received my first 599 reports from Europe (two of them!) as well as two SWL cards from Russia for that activity. The rig: 100w to quarter wave 40 ft vertical inverted L with 22x65 ft radials.)

"I was excited for the weekend conditions but Jan 13-14-15 turned out to be stinko for DX. Amazing how things change on Top Band. Gotta get 'em while you can."

Thanks, Robert.

Don't miss "The Penticton Solar Flux Receiver," an article on pages 39-46 in the February 2013 issue of QST. This gives a great explanation about where the solar flux numbers in our bulletin originate. It answered questions I had about the process, such as how they handle readings that go off the scale during a space weather event.

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://myplace.frontier.com/~k9la/.

Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation.

Sunspot numbers for January 17 through 23 were 74, 56, 46, 48, 50, 53, and 68, with a mean of 56.4. 10.7 cm flux was 122.7, 115.2, 106.7, 106.6, 108.3, 110.3, and 104.9, with a mean of 110.7. Estimated planetary A indices were 13, 9, 7, 9, 4, 1, and 1, with a mean of 6.3. Estimated mid-latitude A indices were 12, 7, 9, 8, 4, 1, and 1, with a mean of 6.
NNNN
/EX

Source: W1AW Bulletin via the ARRL.

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