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The K7RA Solar Update


We saw a nice run of eight days with a large sunspot, but none have emerged in the six days since. Unlike other recent spots, this one did not appear just for one or two days and then vanish. Sunspot numbers for July 9-15 were 15, 13, 0, 0, 0, 0 and 0 with a mean of 4. The 10.7 cm flux was 69.1, 67.8, 68.2, 68, 67.2, 66.6 and 66.5 with a mean of 67.6. The estimated planetary A indices were 6, 7, 4, 5, 10, 8 and 5 with a mean of 6.4. The estimated mid-latitude A indices were 6, 7, 2, 4, 5, 6 and 3 with a mean of 4.7. Geophysical Institute Prague predicts quiet conditions for July 17-20, unsettled July 21, quiet to unsettled July 22 and back to quiet on July 23.

Check the data and note the Sunspot Area -- expressed in millionths of a solar hemisphere -- kept growing after the daily Sunspot Number peaked at 26. The solar flux dropped below 70 on July 9, two days before the disappearance of this latest spot, and it has stayed there since. Solar flux is expected to rise to 70 or above July 25-August 5. The same 45-day forecast (I am looking at the July 16 forecast) predicts continued quiet and mild geomagnetic conditions, with planetary A index of 5. The only predicted larger values we see for the next few weeks are 10 on July 21, 8 on July 28-29 and 8 and 7 on August 5-6. This is a wonderful aspect of the weak solar wind that does not play havoc with propagation as it does during stormier times.

Many of us have been longing for the days of daily sunspot numbers above 100, but there was a downside, and that was from heightened geomagnetic activity. While this could be nice for VHF operators wishing to aim their beams north and refract their signals off of aurora, for everyone else -- especially those at higher latitudes -- the effect on HF was not a good one. I was looking in old issues of our propagation bulletin for examples, but found that our archive online only goes back to January 1995, and we didn't begin recording any geomagnetic numbers until October 1996 (when it was suggested by Robert Wood, WB5CRG, now W5AJ). It began with just the planetary A index in ARLP042 on October 11.

But looking back in bulletins from 1997 -- and especially 1998 -- we can see geomagnetic indicators that could wipe out HF communications for days at a time, causing some operators to believe that their radio was broken or feedline was cut. Go here and click on the "Show older bulletins" link toward the upper center of the page. Any time the A index is above 15, conditions may begin to get rough. For 1997, check the bulletins numbered 40, 42, 44, 46 and 48. Note that on some days, the planetary A index could get into the mid or high 20s, or even worse, the 40s or 60s. ARLP048 from 1997 describes a severe geomagnetic storm.

Conditions became tougher in 1998. For that year, check out bulletins 13, 18, 19, 27, 30-33, 35, 36, 40, 43, 46 and 47. Some days had planetary A index readings of 48, 52, 60, 69, 78, 96, 112 and even 121. This made HF conditions tough all over, but talk to someone who was trying to operate from Alaska in 1998. Ketchikan is above 55 degrees North latitude, and Juneau above 58, but Anchorage is above 61 degrees and Fairbanks, nearly 65 degrees north latitude -- about 120 miles south of the Arctic Circle. The further north you are, the more pronounced are the effects of geomagnetic disturbances. So enjoy this weak solar wind. It wasn't always like this.

Bob Leo, W7LR, 88, of Bozeman, Montana has worked with radios for many years. Bob reports a personal first on July 9 when he heard Europe on 6 meters, which he says is new and exciting. At 1356 UTC on 6 meter CW, he spent 30 minutes working CT1HZE (Portugal) with strong signals. Bob was running 100 W into a 7-element Yagi at 45 feet.

Bill Gannaway, a reader in Greenville, Texas, experienced some dramatic sporadic-E skip on July 10. Around 2200 UTC, Bill was driving home from work and trying to listen to a strong local station when it was covered over by a station in Tucson. He tuned up the dial and found a number of Phoenix and Tucson stations all up the band. Check out this useful tool for identifying broadcast stations by frequency, location and call sign -- click on "Advanced Search."

Robert Forsman, WK5X, of Stuart's Draft, Virginia, reports an interesting 6 meter experience on July 6: "I've often wondered about what the shortest possible single-hop distance would be on 6 meter sporadic-E. Until the opening of July 6 of this year, my personal shortest QSO via 6 meter sporadic-E was just a bit longer than 300 miles. During these types of openings, I work grid squares that are otherwise difficult. Around 2300 UTC on July 6, my wife informed me (I was in the other end of the house) that my FT-897D, which I had accidentally left on and parked on 50.095 MHz, was 'beeping loudly' and that I needed to 'go turn that thing off.' I thanked her for alerting me to the band opening.

"I'm not used to hearing 8s on 6 meters. From my QTH in Virginia's Shenandoah Valley, most of the 8s that I've worked have been either in the Upper Peninsula of Michigan or a mountaintop contest station in nearby West Virginia. After settling at the rig, the first station that I worked was KA1VHF near Columbus, Ohio. The second station that I worked was KA8HOK in Millersport, Ohio at a distance of only 234 miles. This was my shortest ever sporadic-E QSO. I also noted that these were some of the strongest non-local signals that I've ever heard on this band. A quick look at EA6VQ's estimated MUF real-time map indicated that the estimated E-layer MUF at the midpoint between KA8HOK and myself was 303 MHz. I believe that that is the highest I've ever seen on the real-time map. Hopefully someone was able to take advantage of this on 1.25 meters. Then, as the MUF over the region began to fall, the band grew longer. My next contact was with northern Indiana, and then my next two were in southern Michigan."

From July 8, Steve McDonald, VE7SL, of Mayne Island, British Columbia, sent this in: "Just a note to tell you of some truly great propagation this past week on the magic band. Early on the morning of July 8, I had been chatting with Jack, OA4TT (140 km south of Lima, Peru), on the ON4KST 50 MHz chat page. As everyone tends to do when propagation is slow, we were jokingly describing what it might take to get a signal from OA to VE7 on multi-hop Es. I posted that we needed the link to Utah or Southern California/Arizona, then into Mexico, Oceania next and finally another hop down to Lima. As we mused, I was hearing strong single-hop into Utah. I left the shack for about an hour only to return to see that Jack had decided, just for fun, to send a few CW CQs toward the USA on 50.1155. With little expectation, I moved the receiver down to Jack's frequency and immediately heard him calling CQ. After picking myself up from the floor, I gave him a short call to which he immediately responded! Signals were weak (449) and somewhat watery and fluttery, leading me to think that this was something other than multi-hop Es. At something over 5000 miles, this mid-summer contact demonstrated why the 'magic band' continues to live-up to its name."

Martin McCormick, WB5AGZ, of Stillwater, Oklahoma, offered some very interesting comments on TV channels 2-6 after the digital TV transition: "Central Oklahoma is now devoid of local signals between 54-88 MHz and the listening is interesting. Sunday, July 12 was the last day of the 'Nightlight' service that Congress authorized (so that one TV station in each market could keep an analog transmitter going with a loop to tell the 1 or 2 people who hadn't figured it out yet what needed to be done to receive TV over the air). KOCO Channel 5 in Oklahoma City was the last full-power analog to go dark there and Monday, July 13 saw a moderate Es opening with Spanish language TV, probably from Mexico, fading in briefly around 1700 UTC on 81.75 MHz."

Martin made a couple of propagation observations: "We have had several days this year in which Mexican signals reached as far up as the low end of the FM broadcast band. When that happened, TV channels 2-6 were full of Spanish -- and sometimes English and French from Canada. In a QST article of a couple of years ago, someone mentioned that it would be nice to see if we can get the 72-76 MHz band for North America. The services there now could move to an equal amount of space in one of the vacated TV channels and make this an interesting DX band.

"A couple of weeks ago, I had left a receiver tuned to TV channel 4 at 71.75 MHZ. We have had very hot summer days and the tropo at night has been fairly impressive. Instead of Es, I got literally hours of a Channel 4 television audio signal from somewhere within the central US. It was running the endless loop nightlight service with no aural ID so I don't know where it was, but it didn't fade out until after sunrise, at which time it went away fast. One can guess that 6 meters and 72 MHz would have been hot during that night. It is strange to spin the dial on a general coverage VHF receiver now and not hear the buzz of video and FM audio landmarks that have been there since before many of our births, but Canada and Mexico will provide good propagation beacons for a few more years to come. I believe it was February QST where I read that 37 US broadcasters will keep their new digital signals on Channels 2-6. I wonder for how long and how many Es openings it will take to change their minds."

Thanks, Martin!

Jeff Lackey, K8CQ, of St Simons Island, Georgia, writes: "Six meters has been great as you have been commenting in your weekly solar update. And I had to tell you that even 'lousy antennas' can work, such as my 15 foot flag pole that I use mostly on HF. But as a joke I found it would load up on 6 meters a couple of years ago. Over the last couple of weeks, I've made about 100 contacts on 6 meters in 19 states and six DX entities. Yesterday (July 15) at 2050 UTC, I worked CT1HZE. He was S5 when I worked him, but later he peaked to S8 working many North American stations. That was my first European QSO on 6 meters. Earlier, around 2000 UTC, I had heard EA8AK (S8) working into Spain, but he didn't hear me. I heard several European stations, but they were all too weak to make contact. So I am now up to 37 states and 13 DX entities on 6 meters with my flag pole antenna. I encourage others in CC&R situations to get on and try out this 'magic band.' It is a lot of fun when Es band conditions exist. The beacons below 50.080 are a great help in knowing if the band is open. And don't be afraid to call CQ -- I have done this many times when the band for me seemed dead. Every once in a while, I am surprised to get a response."

Don't forget the CQ World Wide VHF Contest this weekend.

Amateur solar observer Tad Cook, K7RA, of 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. Check here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.



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