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Sunday, March 21, 2010

Propagation and Monitoring on 11 MHz




This is from the latest ARRL Propagation Bulletin, of March 19, 2010:

"On March 6-9 we got a taste of the bad old days from 2008-2009, when there were frequent stretches of zero sunspots. After March 9, activity picked up, and we hope there is no end in sight to the much-welcome sunspots.

This week, March 11-17, average daily sunspot numbers increased from the previous period from 12.4 to 29.4. Thursday March 18 had a repeat of Wednesday's sunspot number, 28. We've looked at various moving averages over the past few years to try to smooth out the bumps and spot trends, and another way to look at it would be the trailing 50-day average of daily sunspot numbers, which on March 18 was 27.34. The fifty day period is purely arbitrary. For the eighteenth of each month, going back to April 18, 2009 the trailing 50 day average was 0.48, 2.44, 5.42, 7.4, 3.14, 0.48, 4.42, 7.42, 8.98, 17.44, 26.12 and 27.34. We can see a positive trend there.

On March 11 new sunspot group 1055 emerged, which followed the arrival of group 1054 the day prior. 1055 lasted a very brief period, and group 1056 appeared March 17. Today group 1054 is fading over the western limb, and it is hard to tell from the STEREO mission if some of the active magnetic areas just over the horizon are new or returning sunspots, or not even fully formed sunspots at all.

One uncertain area looks to be a day or less away, and beyond that, the only thing visible is on the other side of the narrowing unseen area on our Sun's far side. At 1045 Friday morning that blind spot covers less than 11.7% of the Sun's total area.

So far in March the average daily sunspot number is 24.2. For all of every month of March since the end of the last century, the average (1999-2009) was 100.5, 203.6, 166.7, 154.3, 119.7, 81, 41, 21.3, 9.8, 15.9, and 0.77. Sobering, isn't it?"

So, sunspot activity is fluctuating....

In the meantime, as we move through the March Equinox, propagation into Melbourne on 11 MHz has been very good around our sunrise window - these entries of March 20 in the 1900-2000 period will be of interest:

11635 ALBANIA R. Tirana English *1945-2000*
11695 IRAN VOIRI English *1930-2030*
11845 ENGLAND RCI-Skelton French *1900-2000*
11875 FRANCE RTI-Issoudin French *1900-2000*
11910 N. KOREA VOK English 1945
11955 GERMANY AWR-Nauen Arabic *1900-2000*
12070 ENGLAND DW-Wooferton German 1930

Stay tuned for many frequency and schedule changes which will come into effect on March 29, for the A10 season!

This weekend, the Warrandyte Festival is underway, in the outer eastern suburb of Warrandyte, 20 km from Melbourne town. I went over there yesterday - joined the throngs - plenty of color and action!

Warrandyte is on the Yarra River, and was the site of the first gold discovery in Victoria in 1851.

See the images!

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