The VK2DJG blog

I hadn’t listened on 6m for some months. I don’t have any antenna other than my HF vertical which tunes on 6m quite reasonably. I was a little surprised to find some beacons:

  FK8SIX on New Caledonia at 0254z
  VK4ABP at Longreach at 0510z
  VK4RTL at Townsville at 0516z

On SSB I heard John, VK4FNQ, in QSO with VK1VP in Canberra (I couldn’t hear the latter).

SB PROP @ ARL $ARLP029
ARLP029 Propagation de K7RA

ZCZC AP29
QST de W1AW
Propagation Forecast Bulletin 29  ARLP029
From Tad Cook, K7RA
Seattle, WA  July 15, 2005
To all radio amateurs

SB PROP ARL ARLP029
ARLP029 Propagation de K7RA

The big patch of sunspots that energized activity less than two weeks ago has drifted around the edge of the Sun. You can see the effects in the falling daily sunspot numbers and solar flux. Average daily sunspot number dropped a little over 63 points to 91.3. At the same time, geomagnetic disturbance increased, so ideal conditions with high sunspot activity and quiet geomagnetic conditions are reversing.

On July 10 a coronal mass ejection from a day earlier hit Earth, and caused a geomagnetic storm. The same day it hit, the planetary A index jumped to 47, and another coronal mass ejection began a journey from the sun. As a result, the planetary A index went back up, this time to 48 on July 12. All this as sunspot numbers and solar flux dropped.

Solar activity is currently increasing, but only from some sunspots that are drifting from view. They may deliver an indirect hit to Earth in the next couple of days. The interplanetary magnetic field, or IMF, is pointing south, which means our Earth is vulnerable. Currently the planetary A index for Friday through Monday, July 15-18 is predicted to be 25, 25, 20 and 12.

Sunspot numbers and solar flux should reach a short term minimum around July 16-19, and another maximum around August 2-5. This is based on the recent peak in activity, and the fact that the sun rotates relative to earth about once every 27-28 days.

This time of year West Coast stations often see good propagation in the evening to the west and southwest, to Hawaii, and down toward Australia, where the season is now winter. 20 meters can be open all night, with 15 and 17 meters showing good propagation through the evening. The East Coast of North America will see good 20 meter propagation into the evening toward Europe, with the band often staying open four or five hours later than it will about a month from now.

If you would like to comment or have a tip, email the author at, k7ra@arrl.net.

For more information concerning radio propagation and an explanation of the numbers used in this bulletin see the ARRL Technical Information Service propagation page at, http://www.arrl.org/tis/info/propagation.html. An archive of past bulletins is found at, http://www.arrl.org/w1aw/prop/.

Sunspot numbers for July 7 through 13 were 149, 111, 126, 78, 68, 52 and 55 with a mean of 91.3. 10.7 cm flux was 124.9, 110.4, 106.6, 101.8, 93.3, 95.3 and 91.7, with a mean of 103.4. Estimated planetary A indices were 8, 5, 19, 47, 23, 48 and 30 with a mean of 25.7. Estimated mid-latitude A indices were 6, 5, 13, 28, 14, 17 and 20, with a mean of 14.7.

NNNN
/EX

SB PROP @ ARL $ARLP028
ARLP028 Propagation de K7RA

ZCZC AP28
QST de W1AW
Propagation Forecast Bulletin 28  ARLP028
From Tad Cook, K7RA
Seattle, WA  July 8, 2005
To all radio amateurs

SB PROP ARL ARLP028
ARLP028 Propagation de K7RA

The Earth-facing disc of the sun went through a tremendous change over the past couple of weeks, ranging from a sunspot number of zero on June 26 to a reading of 192 on July 4. Along with this, geomagnetic conditions were very stable, an ideal combination for HF operators. Average daily sunspot number for the previous reporting week was only 19, but it jumped to over 154 this week, a huge change. Average mid-latitude A index was lower by two points, with the planetary A index down by nearly five.

This is an example of how even toward the solar cycle minimum, there can still be tremendous variation in activity from day to day. Those graphs you’ve seen of sunspot cycles are generally smoothed out using a moving average. In other words, if you draw your graph of daily sunspot numbers with every dot or section of line representing an average of the readings from the 90 days before and the 90 days after that date, the squiggly line tends to smooth out. This sort of representation helps us to visualize trends, and pay less attention to the day-to-day variation.

The July 4 sunspot number of 192 was the highest reading since November 26, 2003. Having the number go from zero to 192 is quite a jump, especially when we observe the last time prior to November 2003 that the sunspot number was zero. This was clear back on the other side of sunspot cycle 23, in 1998 on January 7-9.

Earlier this week someone sent an email about the big increase in sunspots, and mentioned a NASA article referenced in this bulletin a couple of months ago, titled ”Solar Myth”. The message was about the fantastic conditions, how 15 meters has been open into the evening, and that even lulls in the solar cycle can have spurts of activity. Unfortunately, the computer on which that email resides has crashed, so around here this weekend will no doubt be spent trying to recover. But we still have the URL for the article, and it bears another reading. Propagation Bulletin 18 referenced the article, which you can read at http://science.nasa.gov/headlines/y2005/05may_solarmyth.htm?list164615.

Yesterday, July 7, an explosion near sunspot 786 (currently aimed squarely toward Earth) hurled a coronal mass ejection, which is expected to cause a mild geomagnetic storm. Predicted planetary A index for July 8-11 is 25, 30, 25 and 15. Solar flux peaked on July 3 at 129.8 (highest solar flux reading since January 19, 2005) and for July 8-11 solar flux is predicted at 120, 120, 115 and 110. Flux values are expected to remain above 100 until mid month.

If you would like to comment or have a tip, email the author at, k7ra@arrl.net.

For more information concerning radio propagation and an explanation of the numbers used in this bulletin see the ARRL Technical Information Service propagation page at, http://www.arrl.org/tis/info/propagation.html. An archive of past bulletins is found at, http://www.arrl.org/w1aw/prop/.

Sunspot numbers for June 30 through July 6 were 96, 122, 168, 179, 192, 181 and 143 with a mean of 154.4. 10.7 cm flux was 102.5, 114.6, 123.8, 129.8, 123.7, 126.8 and 123, with a mean of 120.6. Estimated planetary A indices were 8, 16, 13, 11, 7, 5 and 5 with a mean of 9.3. Estimated mid-latitude A indices were 4, 12, 12, 9, 5, 3 and 3, with a mean of 6.9.

NNNN
/EX

Copyright 1995-2005 The American Radio Relay League.

Another golden oldie. While reminiscing through my old logs, I note that the first contact I had on 2m via an aurora was on September 15, 1974. I made 47 QSO’s across 6 countries in the 12 hours between 3pm and 3am local time. All on SSB, all using 10 watts!

At that time I was living in Aberdeen, Scotland, and using the callsign GM8IKT. Aberdeen being over 57 degrees north of the equator was a great site for aurora - unlike my present QTH which is 30 degrees south of the equator. I’ve never heard anything auroral from here.