Saturday, August 23, 2008

Propagation Forecast Bulletin update

Propagation Forecast Bulletin 35 ARLP035
From Tad Cook, K7RA
Seattle, WA August 22, 2008

ARLP035 Propagation de K7RA

Another week of quiet sun, but on Wednesday and Thursday, August 20-21, a new spot seems to be emerging. There is no sign that it is anything other than an old cycle 23 spot. reported it with a sunspot number of 11 for August 21, but NOAA did not,
reporting zero instead for Thursday. A late Thursday image at suggests a spot in the northern hemisphere on the left side of the image.

About a year and a half ago in bulletin ARLP010 we speculated whether solar cycle minimum had been reached. The same issue mentioned a personal quest by JQ2UOZ to work DXCC at the solar cycle minimum running only one-half watt on 17 meters and higher using dipole antennas. In an email this week he said he has reached his goal. So far he has worked 138 countries, and you can see details on his web site at .

Tony Dixon, G4CJC produces a weekly report on the ten meter band, including calls heard, at . Even at the bottom of the cycle, there is still propagation on 10 meters, although it tends to be sporadic-E skip, rather than F layer propagation we see when there are more sunspots.

This week NASA released an article with details on upcoming solar research initiatives, ranging from soon to 2015. One that is expected to launch in 2015 will place four satellites around the sun and it will observe solar activity on the other side, facing away from Earth. See details at .

For more information concerning radio propagation, see the ARRL Technical Information Service at For a detailed explanation of the numbers used in this bulletin, see . An archive of
past propagation bulletins is at .

Monthly propagation charts between four USA regions and twelve overseas locations are at /.

Instructions for starting or ending email distribution of this bulletin are at .

Sunspot numbers for August 14 through 20 were 0, 0, 0, 0, 0, 0, and 0 with a mean of 0. 10.7 cm flux was 65.9, 65.3, 66.2, 66.5, 66.2, 67.3, and 65.9 with a mean of 66.2. Estimated planetary A indices were 5, 4, 5, 7, 23, 8 and 6 with a mean of 8.3. Estimated mid-latitude A indices were 4, 3, 4, 5, 15, 7 and 5 with a mean of 6.1.
(Source: Dave Raycroft)