Preparing for the Propagation Winter


Preparing for the Propagation Winter (http://www.eham.net/articles/32973).

It is common knowledge now this will be one of the lowest sunspot cycles of many Amateurs time in radio. Following is a summary of where we are, where we are headed in this cycle, and what we can expect in future cycles and why. Whether you are a DXer, Contester or just a casual operator, what our Sun is doing will affect tremendously how we spend our time, money and resources toward this hobby.

We are all familiar with the typical sunspot cycle duration 11 years plus or minus. There is a much larger cycle however with the sun…decades of high and low solar activity spanning 75 to 100 years – encompassing several sunspot cycles. All of us today have had the fortunate experience of being in Ham Radio during one of the highest periods of solar activity 1950 to 2009. The graph below courtesy of K9LA shows a bar graph of all solar cycles with the exception of 24, which will fall in well below the top of cycle 23. Link:

http://k9la.us/A_Look_at_All_Twenty_Three_Solar_Cycles.pdf

Clearly, there are periods (decades) of high solar activity, followed by decades of low solar activity. A rough interpretation would be 4 up cycles and 3 down. This large “Macro Cycle” of the sun is basically 75 to 100 years. Another link shows how low cycle 24 is compared to other cycles:

Here is a recent graph showing the past two cycles including cycle 24.

Here is the link for those who wish to read the article in it’s entirety.

http://globalnews.ca/news/1509661/why-our-suns-solar-maximum-is-one-of-the-weakest-in-modern-times/

Clearly the trend is down. Focusing in on our current sunspot cycle reveals other unique features and confirms the downward direction. It seemed to take “forever” for cycle 24 to get off the ground…normally we see solar flux values climbing above 100 on average 18 Months after a cycles bottom – it took cycle 24 2 1/2 years to accomplish this (Feb. of 2011) One of the key indicators of a cycles strength and intensity is how it starts. [Slow starts will usher in a weak low cycle, strong fast starts produce strong high cycles, as there are no exceptions] That same year we had a faint peak November of 2011, and as an author of the 2014 ARRL DX Contest put it: “A Micro Peak” this year. The peak being defined as highest average monthly solar flux of 170 set February of 2014. (This has been the first sunspot cycle where the second peak was higher than the first) Subsequent to that Month, average Monthly solar flux has declined month after month, with a slight rise in July. The Average Monthly Solar Flux is what we as Radio Amateurs should keep our eye on – the smoothed sunspot number is a “lagging indicator” and averages what happened 6 Months ago. Watching it is akin to focusing on the hot dog vendors at a Football game instead of watching the play on the field.

The driving force behind all of this is not so much the number of sunspots, but the magnetic size and complexity of the sunspot groups. Astronomers Livingston and Penn at have measured the strength of sunspots clearly showing a decline in complexity and strength since 1995. Graph and link follow:

Drawing from the graph, magnetic strength of the sunspots needs to be at least 1,500 Gauss to form spots. The conclusion is with the present trend, sunspots will disappear by late 2015 or 2016. Drawing from recent activity in cycle 24, the main driver of our peak in 2014 was not the number of sunspots, but the increase in size and magnetic complexity vs what it has been from the beginning of cycle 24. (Basically we had a pause in the downtrend of declining sunspot strength) {We’ll take it!} Cycle 24’s downward trend is ratified by other factors: 1. Clustering of sunspots toward the center of the sun, wide swings in monthly highs and lows, slow continuous month to month declines in solar flux values, and the average number and size of sunspots is on the decline. What does this all mean and what can we expect? Our last really good Fall season of HF propagation will soon be upon us, take advantage of it…we will be lucky to see good 10/12 Meter propagation this Fall, and 2015 will probably be the last year for good high band propagation: 17,15,12, and 10 Meters. We will quickly “ratchet down” and the low period of the cycle (solar flux values of 70-80) will be reached much sooner as we will have much lower highs from which to fall. See graph below:

Keep in mind Cycle 23 ( a low but normal cycle ) took 5 years to fall from it’s high in late 2001 to it’s low period in 2006, cycle 24 may not be in a free fall, but it’s decline will occupy a much shorter time span.

Looking our even further, unless the trend in lower macro solar activity is shorter, or the decline in the magnetic strength and complexity of sunspots reverses itself, cycle 25 will even be lower…. graph below:

I personally wish it were not so…however in my business on key thing I have always remembered: ” Pay attention to what the Market is telling you, rather than what you think it should do.” In this case it’s data…the data is telling us we are heading toward a much much lower period – this cycle, cycle 25 and possibly cycle 26. This has happened before; it’s just that none of us today were alive to experience it. This is coming, just like a Tsunami after a mid ocean earthquake – there is a building consensus and others will join the chorus when “it is safe for them to do so” Remember the low years of 2007, 2008, 2009, 2010? They will seem like a walk in the park compared to what is coming.

Randy W7TJ

via Preparing for the Propagation Winter.

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This fascinating article first appeared on 04 September 2014 on http://www.eham.net/articles/32973.  According to Randy Crews (W7TJ), amateur radio operators are headed for some poor propagation in the years ahead.  With that in mind, it may be prudent to explore the lower HF bands (160, 80, 60, and 40 meters), where conditions aren’t so bad. Some ambitious hams are also exploring the possibilities of 630 meters (around 472 kHz).  I see more antenna articles on this interesting band every week.  Once the FCC firms up its rules for this band, we can explore the frequencies where early contacts once took place.  A good book to read for this area would be Clinton De Soto’s “200 Meters and Down,” a volume that explores the early days of amateur and commercial radio in the traditional “radio basement” of wavelengths longer than 200 meters.  Even though propagation on 20 through 10 meters will not be optimum, expect some good days on 20 meters and a few interesting openings on 10 meters.  You just never know when the upper HF bands will be open…be ready!

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Until next time,

Aloha es 73 de Russ (KH6JRM).

 

 

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