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The K7RA Solar Update


Average daily sunspot numbers for January 15-21 dropped 50.7 points relative to the previous seven days, to 61.9. Average daily solar flux declined from 151.3 to 126.2. For the past ten days sunspot numbers have remained below 100. This benchmark has no special significance, but the last time there were this many consecutive days with double-digit sunspot numbers was October 5-20, 2014.

Geomagnetic numbers indicated more stable conditions, with average daily planetary A index declining from 9.6 to 6.4, and average daily mid-latitude A index dropping from 8 to 4.7.

The latest prediction from USAF/NOAA has solar flux at 130 and 135 on January 23-24, 130 on January 25-26, 135, 140 and 145 on January 27-29, 135 on January 30 through February 1, 130 on February 2-3, 125 on February 4-6, 130 on February 7-9, 125 on February 10-11 and 120 on February 12-13. Solar flux reaches a low of 115 on February 18, and peaks again at 135 on February 26-28.

Predicted planetary A index is 15 on January 23-24, 18 on January 25-26, 8 on January 27-28, 12 on January 29-30, 15 on January 31 through February 1, then 12, 15, 12 and 5 on February 2-5, 10 on February 6-7, 8 on February 8-9, 5 on February 10-12, then 8, 5 and 12 on February 13-15, 10 on February 16-18, and 8 on February 19-20.

F.K. Janda, OK1HH, predicts geomagnetic activity will be active to disturbed on January 23, quiet on January 24, mostly quiet January 25, active to disturbed January 26-28, quiet January 29, active to disturbed January 30, mostly quiet January 31, disturbed February 1-2, quiet to unsettled January 3, quiet to active January 4, active to disturbed February 5, quiet to active February 6-8, mostly quiet February 9-13, quiet to active February 14, and quiet to unsettled February 15-17.

Randy Crews, W7TJ, of Spokane, Washington posted these observations:

“Thanks for the link and update from NASA in your last bulletin. A couple things I wanted to add to amplify on the trend and outline a unique historical perspective.

“Cycle 24's peak is past and will fall into the ranks of the lower Sunspot cycles 10, 12, 13, 14, and 16. NASA’s article pointed out Cycle 24 being the smallest since Cycle 14 in 1906. It will probably mirror cycle 12 or 13 finishing with a smoothed sunspot number in the high 70s low 80s plus or minus. A few additional points make this cycle unique in addition to the second peak being higher than the first: In past strong sunspot cycles (21, 22, and 23) we have had what I would call the ‘top 3’ being 3 outstanding years of high solar activity (the year prior to the peak, the year of the peak, and the year after where Solar flux values have averaged between 150 and 225).

“Tying this observation to Cycle 23 (a lower but normal cycle in 2000, 2001, and 2002), during these peak years propagation on 10, 12, and 15 meters was outstanding almost all of the time. Cycle 24 has bestowed just a little over one year of this type of propagation - late 2013 to present. This is graphically seen from the solar activity report from this Web link:

“Things become more interesting with the fact Cycle 24 will obviously finish with a smoothed sunspot number of less than 100. This is the first time this has occurred since Cycle 16 finished in 1933 (over 80 years ago!). See this link with the corresponding data:

“Graphically, Cycle 24 will fit into the BIG picture as follows, accurately done by K9LA:

“Connecting the dots from the graphs, historically there have been decades of high and low solar activity spanning several sunspot cycles. As one source has pointed out, got most of our radio amateur lifetimes we have experienced some of the highest solar activity periods in history, 1950 to 2009. The graph from NASA of the current trend pretty well sums up the overall direction:

“To summarize, Cycle 24 will be a low cycle very likely to be followed by several other low or even lower cycles - supported by the current and historical data. We should make the most of the current band conditions and upcoming DXpeditions because it certainly looks as if we are heading toward a ‘propagation winter.’"

Thanks, Randy. I do not know if we are headed toward a “propagation winter” and quiet sun or not, although plenty of experts much smarter than me might think so. I remember when some of the best minds made a case for the upcoming Cycle 24 to be the biggest ever, and of course it did not turn out that way.

I hope to be around for the next cycle, might even see the one after that, but I doubt I will see three cycles out. When I started as a Novice it was Cycle 20, right after the big one, and it sure seemed weak!

I heard from Rich Zwirko, K1HTV, of Amissville, Virginia. He wrote: “Other than a few Es openings, 6 meters has been pretty quiet the past few weeks. I think that we have seen the last of any 50 MHz E-W F2 skip for this solar cycle and possibly future cycles. Magic Banders will have to rely on summer multi-hop E-skip and SSSP chordal openings for the next long-haul 6 meter DX contacts.”

He also mentioned that his son, Andy, K1RA, of Warrenton, Virginia is operating a RaspberryPi as a multi-band HF WSPR beacon running only 10 milliwatts. (RaspberryPi is a tiny and inexpensive computer that is popular as a microcontroller. See

His computer/transmitter not only changes bands automatically according to a timing cycle, but the microprocessor actually generates the RF and connects directly to the antenna feed line, via some simple filtering. The signal is output as a square wave, but the harmonics are easy to filter out and at 10 mW are simple to control. The beacon call sign is KW4VA and the grid locator is FM18cr.

According to Andy, “I've been running a Raspberry Pi and the JamesP6000 WSPRryPi code under my club call KW4VA recently, which you can read about at the following URL for info, links and DX spot maps:

“In short, the Raspberry Pi CPU can natively generate ~10 milliwatts of RF from 0-250 MHz off one of its GPIO pins. The WSPR code is based off some earlier code developed in the UK to allow generation of FM signal >100 MHz. See

“I'm running one of the IO pins to external wire antennas. I was stuck at about 7500 km for my best DX for a few years until this past week when I was spotted by ZS6AF on 17 meter at 13322 km, then in the last two days by ZL1RS on 20 meters at 13811 km and finally VK2DDI on 30 meters at 15729 km. Here are the spots from the WSPR propagation database:

Time Stamp Frequency (MHz) SNR (dB) Reporter Grid Distance (km)
2015-01-19 08:22 10.140240 -27 VK2DD QF55hf 15,729
2015-01-15 10:18 14.097116 -24 ZL1RS RF64vs 13,811
2015-01-08 21:14 18.106032 -22 ZS6AF KG54mk 13,322

“I've been playing with very low power WSPR for a while now. In the past I'd been using a PIC controller by AA0ZZ and a 0-60 MHz DDS board by N2APB that also put out ~10 mW and was using a 30 meter dipole in the attic at 30 feet. Then I was stuck on one band at a time, usually 10 meters. I'm sure the outside dipoles and wires at 45 feet that I am presently using help a bit. With the use of the Raspberry Pi system, I have been able to automatically band hop. I think this too has helped to increase my DX spots by other WSPR stations.”

This weekend features the ARRL January VHF Contest (see and and the CQ World Wide 160 meter CW Contest (

For the 160 meter CW contest we would like to see very quiet geomagnetic conditions. OK1HH predicts disturbed conditions on Friday, then quiet on Saturday and mostly quiet Sunday. Quiet is a good outlook, although I don’t know what the effect of Friday’s conditions might be on the rest of the weekend if they are disturbed.

NOAA/USAF predicts an A index of 15 on Friday and Saturday and 18 on Sunday. This is neither quiet nor disturbed, but I would characterize it as unsettled conditions. Let’s hope for dead quiet geomagnetic conditions over the entire weekend. Have fun!

Following up on last week’s link to an article about the National Radio Quiet Zone and the people who flock there, N7SO sent another article:

We also heard from a ham who used to work there, Rob Welsh, N3RW, who wrote: “I was previously employed at NRAO Green Bank (see on a Milky Way mapping project. Given that NRAO GB Is in the National Radio Quiet Zone, I was given permission to put my QRP rig on the air on 17 meters using the HF Bruce array antenna at the observatory entrance. Few stations I worked believed that I was running just 5 W. With about 100 feet of RG-58 between the dorm and the antenna, I bet I was radiating more like 3 W at best.”

Info on a Bruce Arrays:

Rob also wrote in a subsequent e-mail: “The Bruce Array at the entrance to the Green Bank site is a rebuild of the antenna used by physicist Karl Jansky, who in the 1930s studied radio noise for the Bell System's HF radio circuits.

“Jansky eliminated all noise sources except one, which occurred 4 minutes earlier each day. In conversations with others, he was told that the stars rise 4 minutes earlier than solar time. As a result, Jansky may have been the first to discover galactic radio noise as he was recording the radio noise emitted by the Milky Way.

“One of my tasks while employed at GB was to perform a VSWR vs frequency plot of the Bruce Array. The center frequency, as I remember, was about 20 MHz, so with a QRP antenna tuner I was able to find a match for the 17 meter band.

“Radio astronomers consider the HF bands as 'low frequency' for astronomical observations. There has been an increase in HF observations at HF with the purpose of identifying galactic sources at lower energy levels.

“Also, at the entrance to the site is a rebuild of Grote Reber's (W9GFZ, SK) 30 foot parabolic antenna. Reber read Jansky's published work and went about measuring galactic radio noise at VHF. See my article in the December 2009 issue of QST titled 'How the Ionosphere Was Discovered'.

“The call sign, W9GFZ, has been issued to NRAO and used at both the Green Bank site and at the Very Large Array in New Mexico. I've observed at both sites. You can see the antenna system at Green Bank by going to and, on the left side of the main page, clicking on 'Other Green Bank Telescopes'. My QSL card shows the 45 foot antenna on the front. That is the system I used to map a quadrant of our galaxy at wavelengths of 3.5 and 2.1 cm. Big antennas sure are interesting!”

For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of the numbers used in this bulletin, see An archive of past propagation bulletins is at More good information and tutorials on propagation are at

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

Instructions for starting or ending email distribution of ARRL bulletins are at

Sunspot numbers for January 15 through 21 were 62, 75, 49, 78, 62, 57, and 50, with a mean of 61.9. 10.7 cm flux was 131.4, 124.7, 121.9, 125.8, 130, 125.6, and 123.9, with a mean of 126.2. Estimated planetary A indices were 6, 7, 7, 5, 5, 4, and 11, with a mean of 6.4. Estimated mid-latitude A indices were 5, 6, 5, 3, 2, 5, and 7, with a mean of 4.7.





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