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 Previous: FOC -- Who Are They? |  Next: FCC Amateur Radio Enforcement Letters for the Period Ending June 1, 2006 |
SEATTLE, WA, Jun 2, 2006--Thanks to Carl Luetzelschwab, K9LA, for writing an excellent propagation report last week.
Solar activity continues to be low as we head toward the bottom of the sunspot cycle. Still, we haven't seen weeks on end with no sunspots, so I suspect the minimum is not quite here. Let's take a look at the monthly averages of sunspot numbers and solar flux for May, compared with the past year.
The average daily sunspot numbers for the months May 2005 through May 2006 were 65.4, 59.8, 68.7, 65.6, 39.2, 13, 32.2, 62.6, 26.7, 5.3, 21.3, 55.2 and 39.6. Average daily solar flux for the same months was 99.5, 93.7, 96.5, 92.4, 91.9, 76.6, 86.3, 90.8, 83.4, 76.5, 75.5, 88.9 and 80.9.
With fewer sunspots, the higher frequencies aren't as useful. There is a direct correlation between the maximum usable frequency (MUF) and the number of sunspots. That's why 10 meters is much more usable at the peak of a solar cycle than at the bottom.
We received several e-mails this week about sporadic E (Es) propagation. This is when unpredictable ionized clouds form in the lower E-layer of the ionosphere and provide interesting and exciting long range propagation. June is a very good month for this in the Northern Hemisphere. Broadcast television DXers, such as Mike Shaffer, KA3JAW, in Tampa report regularly receiving TV broadcasts from stations in Mexico and Central America. Paul Gray, N0JAA, in east-central Florida reports working 12 meter Es from time to time into Virginia and New York
Six meters also can be exciting. Bill Van Alstyne, W5WVO of Rio Rancho, New Mexico, writes:
"Sporadic E season is upon us, and yesterday (Sunday, May 28) saw one of the best 6-meter North American sporadic E openings of the past few years. At one point late Sunday morning, 6 meters was open coast-to-coast, with QSOs between CA and the east coast via long double-hop propagation (or maybe triple-hop in some cases) taking place frequently. Here in New Mexico, I was hearing and working both coasts and pretty much everything in between with S9+ signals.
"Many stations in the eastern part of the country, and even out west here, worked a lot of DX in the Caribbean and Central America, but my path in that direction is poor, and I didn't hear any of it.
"I did pick up a number of new grid squares, though, including EL94 (Florida Keys) on a double-hop path and a cool backscatter contact with DM34 in central Arizona. Backscatter is unusual on 6 meter sporadic-E (in my experience). My theory is that a typical sporadic E cloud is much more planar a refractive medium than the F2 layer, and doesn't scatter energy as much in off-beam directions. Thanks to W7MHW for hearing my weak signal through the pile-up of S9+20 signals from the southeast states.
"Heard several guys talking about sporadic E on 2 meters, but I think it was pretty limited. I didn't hear any really super-short skip on 6 meters; my guess, from the minimum skip distances I was hearing, is that the Es MUF was somewhere around 100-120 MHz -- at least in these parts."
For the next few days, it looks like solar wind from coronal holes could be mildly disruptive. The planetary A index forecast for June 2-3 is 20, then settling down to quiet conditions a couple of days later. Average daily sunspot numbers were up this week over last and are expected to rise slightly over the next few days.
Higher sunspot numbers mean higher MUFs, but 20 meters still should be your best band for reliable worldwide propagation. For instance, California stations can work Japan on 20 meters currently around 0600-1600 UTC, while the best 20-meter opening to Australia should be 0630-1300 UTC. If you are in Georgia, the best 20-meter opening to Europe should be around 2230-0200z and 0430-0830 UTC. But you can work out your own paths to any location. Just use the suggestions in an earlier bulletin.
For more information concerning propagation and an explanation of the numbers used in this bulletin see the ARRL Technical Information Service Propagation page. An archive of past bulletins is on the ARRL Web site.
Sunspot numbers for May 25 through 31 were 33, 51, 69, 78, 54, 51 and 44, with a mean of 54.3. 10.7 cm flux was 83.7, 81.6, 83, 84.7, 81.1, 80, and 78.4, with a mean of 81.8. Estimated planetary A indices were 5, 5, 3, 7, 3, 9 and 6, with a mean of 5.4. Estimated mid-latitude A indices were 4, 1, 1, 5, 1, 7 and 4, with a mean of 3.3.
Amateur solar observer Tad Cook, K7RA, Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version appears in The ARRL Letter. Readers may contact the author via e-mail.
| Previous: FOC -- Who Are They? | Next: FCC Amateur Radio Enforcement Letters for the Period Ending June 1, 2006 |
