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Author Topic: Propagation  (Read 873 times)

Fansome

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Propagation
« on: December 22, 2012, 0202 UTC »
SB PROP @ ARL $ARLP051 ARLP051 Propagation de K7RA

ZCZC AP52 QST de W1AW Propagation Forecast Bulletin 51 ARLP051 From Tad Cook, K7RA Seattle, WA December 21, 2012 To all radio amateurs SB PROP ARL ARLP051 ARLP051 Propagation de K7RA

It is Friday, December 21, 2012, and the world did not end. To herald this non-event, NASA even produced a wonderful video explaining how the whole thing was a misconception anyway. The Mayan calendar is like an odometer, and when it gets to 999999, it just roles over to 0 and begins anew.

You can watch the video at http://www.youtube.com/watch?v=QY_Gc1bF8ds and be sure to check out the HD and full-screen options.

As expected, Phil Plait of "Bad Astronomy" also provides a nonsense-free assessment at http://goo.gl/xknYD. Check his blog at http://www.badastronomy.com and http://www.slate.com/blogs/bad_astronomy.html. Phil, a solid friend of science, refers to the non-event as the "Maya Notpocalypse."

Solar activity increased this week, but only slightly. Similarly, geomagnetic indices were up as well, but not by much.

Average daily sunspot numbers increased 24.5 points to 72.1, and average daily solar flux was up by 14.8 points to 117.5. Expressed as a percentage, the average daily sunspot number increase seems large, but it is still in the area of low solar activity.

Average daily planetary A index increased 3.4 points to 5.4, and average daily mid-latitude A index increased 2 points to 5.1. This is still low activity, with the A index good for 160 meters, but sunspot numbers not what 10 or 15 meter operators would like to see.

NOAA and USAF predict 10.7 cm solar flux numbers at 115 for December 21-24, 120 on December 25-27, 100 on December 28-29, 95 on December 30 through January 3, 100 on January 4, 105 on January 5-7, 110 and 115 on January 8-9, 120 on January 10-12 and peaking at 125 on January 13-14. The prediction shows flux values dropping below 100 on January 26-30, and then rising above 100 in February.

We see planetary A index at 5 on December 21-22, 8 on December 23-24, 5 on December 25-28, 8 on December 29, then 5 on December 30 through January 12. We see a big jump to 16 and 12 on January 13-14, then dropping back to 5 again into February.

OK1HH believes that "Present type of development in solar active regions and its configuration reduces the reliability of predictions." He also says the geomagnetic field will be active to disturbed on December 21, mostly quiet on December 22-23, quiet on December 24, mostly quiet December 25, quiet December 26-28, quiet to active December 29, quiet December 30-31, mostly quiet January 1, quiet January 2-5, quiet to active January 6, quiet to unsettled January 7, quiet January 8-9, mostly quiet January 10, quiet to unsettled January 11-12, active to disturbed January 13.

Tom Morton, CXC7TT from Rocha, Uruguay, writes concerning the ARRL 10 Meter Contest (December 8-9, 2012): "Due to house guests, did not participate in contest, except for roughly 30 contacts. I turned the rig on right at 0000z on Friday night and 10m was pretty much dead (that's 2200 local). I did hear and work XV1X (Viet Nam) at 0001 beaming LP over the SW tip of the USA so band had gone really long. XV is about 12,000 nm from here LP. The next morning, typically good for EU, was pretty dead. The few big guns in EU were coming thru but not with really big signals. FH8PL at 1217z on SSB and T6LG at 1218z on CW were pretty easy to work. The next day A45XR at 1600z on 10 CW was another easy catch. Around 1400z on Sunday the band really opened up to the US. My P3 had signals from 28001 that finally tapered off around 28091 and SSB was crowded from 28300 to 28553. It was definitely a South American day as two local multi-single stations were running Qs big time. CW5W and CX5BW were within 200 Qs of each other by mid afternoon Sunday. I think Jorge and his crew, CW5W, may have the top score with over 3200 Qs.

"My rig is modest K3/100 to Acom 1000 and 3 ele SteppIR at 17 meters high.

"BTW, I never reported this before but last April 3 at 1545z I worked A92IO on 6 meters for my best DX ever; a couple hours later, worked 3 4X/4Z on 6 meter CW. Previously I had worked some eastern/mid west USA, a few EUs and handful of Caribbean stations."

Thanks, Tom!

Peter Matsunaga, WH6EAU - who operates from Oahu's south coast with 50 watts into an end-fed wire - also had 10 meter contest comments: "From a limited time working during the contest period, propagation seemed better on Saturday than Sunday. On both days, I could work only one US station, in Texas. My QTH seems to be in a dead spot for much of continental United states due to a nearby mountain mass. Otherwise I could work S. Brazil, Uruguay, Chile, Argentina, Australia on Saturday, and Japan on Sunday. Signal strength to Australia was particularly strong at times."

Kevin Seeger, NC6V of Corona, California wrote also about the 10 Meter contest: "As N9LB experienced I too noticed the band from time to time just going dead. I checked my antenna and coax a few times to see if they were still there. E skip openings were very, very rare to almost nonexistent. The strangest propagation was a severe echo on Sunday I was hearing from stations on CW located in Ohio and Pennsylvania. At times it was so bad I couldn't copy their calls.

"I worked most states east of the Mississippi but missed the whole W7 call area and a big part of the W0 call area. Several JAs were worked Sunday afternoon and working into South America was a breeze."

Gerald Fasse, W8GF of Warren, Michigan wrote, "Among the toughest DX paths from Southeast Michigan is Cambodia (regular path heading 350 degrees, and 14,000 kM). My only need was and still is 30 Meters. Many 30 Meter spots were noted on the DX Cluster coupled with frantic dial spinning but nil copy here. But I did manage to make a single 20 Meter CW QSO at 1830Z on December 14. Checking W6EL's propagation program for openings to the SE Michigan area it was noted that possible openings occur between 1600Z and 1900Z for that date. The point being that XU1A CQed again and again that day with few QSOs noted probably because mid-day openings to SE Asia are not expected. Don't always depend on the DX cluster for rare and unusual DX info. Tune your radio!"

And finally, Jon Jones, N0JK had some 6 meter E-skip to report: "A winter 6 meter Es opening the evening of December 16 (17th UTC) from the Midwest across the southern states. W4IMD EM84 worked at 0112 UTC and heard WA4NJP loud. The WB5LLI/b EM40 copied at 0130 UTC." Jon is in Lawrence, Kansas in EM17.

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 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.

Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins.

Sunspot numbers for December 13 through 19 were 77, 71, 88, 74, 83, 66, and 46, with a mean of 72.1. 10.7 cm flux was 116.6, 119.2, 122.4, 119.5, 115, 116.2, and 117.5, with a mean of 102.7. Estimated planetary A indices were 3, 3, 7, 5, 10, 6, and 4, with a mean of 5.4. Estimated mid-latitude A indices were 2, 4, 7, 5, 9, 5, and 4, with a mean of 5.1. NNNN /EX