Propagation de K7RA

For the past ten days we've observed no sunspots at all. Periods like this, or longer, are expected at the bottom of the sunspot cycle.

As mentioned in a recent bulletin, the latest projection for
smoothed sunspot numbers from NOAA Space Environment Center has the solar minimum at February through April 2007, with a smoothed sunspot number of 11.

You can see the table on page 10 of the Preliminary Report and Forecast at, http://tinyurl.com/yvw2ke.
Another way to look at it is that the minimum is projected between December 2006 and July 2007, with a smoothed sunspot number of 12 or lower.

Randy Crews, W7TJ notes that the graph at http://www.dxlc.com/solar tells the story on recent trends.

But reports still arrive weekly of operators working long distance, even at the bottom of the cycle. Mike Carter, K8CN of Durham, New Hampshire says he runs 50 watts CW into a wire 60 feet long and 20 feet at its highest. He's worked a lot of South Pacific DX on 40 meters from 1100-1200z, and Europe, Africa and the Caribbean on 30 meters around 2100-2300z.

The lower part of the HF spectrum is a good place to operate at the bottom of the sunspot cycle. Unlike 10 or 15 meters, 160 and 80 meters won't be bothered by a low MUF (Maximum Usable Frequency), a consequence of the lack of sunspots. With less solar activity comes less problems with geomagnetic disturbances, which can be frequent toward the top of the cycle.

Wednesday night about an hour after local sunset I operated 60 meters from my car, using one of those inexpensive popular single-band mobile whips mounted on the trunk. This antenna can't be very efficient, as the length is only about .045 wavelength. 60 meters is an unusual channelized band, with just 5 channels, the top at just above 5.4 MHz. Upper-sideband SSB is the only permitted mode, with transmit power limited to 50 watts ERP. The atmospheric noise was high, and the static crashes probably from far-away
thunderstorms.

I made contact with Frank Miller, K9HMB of Harvard, Illinois, nearly 1700 miles to the east of me, and was surprised to receive an S9 signal report. Later, a glance at his antennas at http://www.k9ns.com told me what kind of station was receiving K7RA so strongly. See if you can find the photo of a large commercial crane "adding a third beam to the stack."

You can see more info on operating in the 60 meter band on the ARRL web site at,
http://www.arrl.org/FandES/field/regulations/faq-60.html.

Dramatic solar images from the Japanese Hinode spacecraft prompted numerous emails this week. The messages referred to a NASA article at http://tinyurl.com/2p5ksk and a New Scientist article at, http://tinyurl.com/ypzhof. Spaceweather.com has a movie from the spacecraft at http://tinyurl.com/ysjrl4 or for today you can see it
at, http://www.spaceweather.com. Clicking on the movie URL should launch a media player on your personal computer. I found the movie better on the second viewing, because all of the content had been buffered and the motion was smooth.

This weekend is the CQ World Wide WPX SSB Contest. There probably won't be any sunspots, although a few are on the way. The sunspot number will probably be 0 or 11. The higher frequencies won't be fantastic, but geomagnetic conditions are expected to be stable and quiet. The U.S. Air Force predicts a planetary A index for March 23-29 at 5, 5, 10, 15, 20, 10 and 5. Geophysical Institute Prague says that March 23 should be quiet to unsettled, March 24-25 unsettled, March 26-27 unsettled to active, March 28 unsettled, and March 29 quiet.

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://www.arrl.org/tis/info/propagation.html.

For a detailed explanation of the numbers used in this bulletin see, http://www.arrl.org/tis/info/k9la-prop.html.

An archive of past propagation bulletins is at, http://www.arrl.org/w1aw/prop/. Monthly propagation charts between four USA regions and twelve overseas locations are at, http://www.arrl.org/qst/propcharts/.

Sunspot numbers for March 15 through 21 were 0, 0, 0, 0, 0, 0 and 0 with a mean of 0. 10.7 cm flux was 69.2, 68.7, 69.3, 70.5, 70.1, 72.6, and 72.8, with a mean of 70.5. Estimated planetary A indices were 8, 10, 8, 3, 2, 2 and 2 with a mean of 5. Estimated mid-latitude A indices were 5, 11, 8, 1, 1, 1 and 1, with a mean of 4.

Source: The American Radio Relay League

• All propagation reports can be found at:
http://www.southgatearc.org/propagation