Sunday, January 12, 2020

Solar Cycle 25 Seems to be Awakening

In the last month, the quiet sun has been broken, not by sunspots from cycle 24 (current) but with spots from cycle 25 starting to ramp up. Live Science has the story:
The two new sunspots, designated as NOAA 2753 and 2754, were seen on Dec. 24 by NASA's Solar Dynamics Observatory — a satellite that monitors the exterior and interior of the sun from a geosynchronous orbit more than 22,000 miles (more than 35,000 kilometers) above the Earth's surface.
Those two spots were gone the next day.  Switching to the ARRL Propagation Bulletin for this week:
A single new Solar Cycle 25 sunspot appeared over the past week, January 1 through January 8. NOAA did not record or number the new spot until January 2, but indicated it (sunspot region 2755) began on January 1.

Then another new Solar Cycle 25 spot emerged on Thursday, January 9 with a daily sunspot number of 14. I was excited to see post "Solar Cycle 25 Continues to Intensify."
Today's sunspot number is still 14 - the leading 1 means one group.  The first two spots, from Dec. 24th, are shown here circled in visual and what appears to be Hydrogen Alpha light (infrared):

The instruments onboard NASA's orbiting Solar Dynamics Observatory captured imagery of the two sunspots from the new sunspot cycle on Dec. 24 — one in the sun's northern hemisphere and one in the southern hemisphere, shown here circled in red. (Image credit: NASA Solar Dynamics Observatory)

How do we know they're not from cycle 24?  Two ways: first, as the solar cycle progresses, spots converge on the equator and nothing shows up as far north or south as these two.  Second, the magnetic polarity of the spots can be measured from the earth (yes, we're in the sun's magnetic field and can measure that from here, 93 million miles away). 

This diagram illustrates the polarization.

This image illustrates the old cycle spots being clustered near the solar equator and the new cycle spots being farther out in latitude.  Black and white represent the magnetic poles being flipped in each hemisphere from the older cycle spots.  (Image credit: Jan Janssens/STCE)

If you're an optimist, you're likely to say, “wow, four new cycle sunspots just since December 24th - this new cycle is really cranking up!”  The other view point is “gee, those are really pretty weak, and the first two were there one day - very short-lived - we've got a long way to go.”  Think of this as solar weather, and just as we differentiate between weather and climate here, whenever it's unusually hot or cold, my tendency is to think it doesn't tell us very much at all other than that we're in the interim between cycle 24 and 25.   

These were weak spots, with very little spread on the disk and no complexity.  Solar Flux measured at 2800 MHz has been at nearly quiet sun levels, a few points better than during the quiet sun last month.  Radio propagation has been largely unaffected so far.  There's nothing here to say the sun is going wild or shutting down.  It's just the time when both cycles can be seen. 


  1. A friend sends me those bulletins and it was nice to see we have the beginnings of Cycle 25. Hopefully propagation will pick up in the next year to 18 months. Been pretty quiet here and while I can hear DX, the signals are usually "S-nothing" to S-2. Thankfully my noise level is very low here compared to SoCal. I can actually use 75 Meters here!

  2. I hate to admit it, but I have not been on HF for a long time. First, because of the fact that financially, I have not been in a position to be able to be involved with it, but partly due to the poor band conditions that we have had to deal with as well.
    I am looking at getting back into CW again, perhaps via QRP. Of course, you can spend as little or as much on that mode. As a high school student, I remember making a tackle in football, and my ham radio teacher was the announcer and mentioned the fact that I was a ham radio operator, when announcing the tackle. That was back in 1977, and I have been a ham since 1972, with a gap of a couple of years, when first married in 1979.
    The days of building your own gear are mostly gone, but I did build a transmitter for CW back then. A 25 watt model using a 6L6 tube, with plug in coils and xtals, and a 600 volt, center tap transformer. I think the plans came from an old QST magazine.
    I have a kit of a QRP transceiver sitting around somewhere, I might have to find and build, in preparation for the coming cycle 25.

    1. First licensed in 1972? I was first licensed in 1976 so you got me beaten.

      Building your own rig is still available and possible. For sure, tons of guys build little QRP rigs, CW or SSB. Then there are tons of cheap and dirty software defined radios (SDRs). It's more a question of what you're after. My last total homebrew job was a 2m transverter to get on 2m SSB with an HF transceiver. Worked great. Still in the closet back there.

      The thing to remember about HF is that at any minute of any day, some HF band is open to somewhere. The only exception is when there's a major solar storm that cause an ionospheric blackout, but those are more common when the sun is at peak activity. Think of 30m and down as nighttime bands with 20 and up as daytime bands. This is all approximate; 30m is open from hours before sunset until hours after sunrise, longer than 40m in both cases.

      These days, I pretty much operate HF through 6m. We're coming up on sporadic E season and possible 6m openings into south America - at least from here in Florida.

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