Friday, 27 November 2020

Solar Cycle 25's Fast Progress




Blog readers may remember my previous blog discussing a more optimistic prognosis for the just-starting solar Cycle 25. It described the then recently-published scientific paper whose conclusion was rather startling:



 "... we deduce that Sunspot Cycle 25 could have a magnitude that rivals the top few since records began."

The scientific paper described the exact opposite of any and all predictions that I have read or have seen referenced, and at the time of publication, was surely a bold and risky claim for the paper's authors. (1)

An over-simplification of the methodologies used to develop their prediction describes the study of the complex relationship involving the Sun's 22-year (Hale) magnetic cycle, the end points of adjoining cycles called 'terminations' and sunspot production, to predict the eventual strength of the new cycle.

The end of the cycle or ‘terminator’ event plays a significant role in the new cycle’s progress, as the shorter the separation between adjoining terminators, the stronger the next cycle will be. The possibilities of Cycle 25 being a truly strong one depends upon (according to the paper) a terminator event occuring sometime before the end of 2020.

Although there has been no official announcement as of yet, it appears that the termination may be presently occuring. Again following the paper, the termination event will produce a sudden and marked upturn in the growth of solar activity and will in fact, switch on suddenly within one solar rotation. As startling as this sounds, it appears to be exactly what is happening on the Sun right now.



Just one week ago, the Sun’s solar flux stood at ~79 sfu (Solar Flux Units) but has climbed rapidly to 110. With several active sunspot regions on the earth-facing side of the Sun and several actively flaring groups about to rotate into view on the backside, it seems as if this sudden growth may be sustainable.

What is particularly encouraging is the activity level of the earth-side spots as well as the ones coming around, with several C and B-class flares continuing to push the flux higher. 

Although it will likely slow and subside, a key indicator of future strength will be the time that it takes to recover and climb again. 

Another interesting gauge of a new cycle’s possible future strength is the number of months needed to reach an average monthly SFI of ‘90’. Strong cycles tend to climb early and rapidly, in order to reach their lofty heights. 

The strongest cycle on record was Cycle 19, the grandaddy of them all. 


Compared to anything before or after, it was a magnificent monster of a cycle for ham radio. Cycle 19 reached the magic SFI 90 value in only 18 months ... Cycle 25 has reached this same point in just 12 months! If this is indeed an accurate marker for cycle strength, and there is no reason to believe otherwise, then maybe we should all hold onto our hats.

We’ve been told for several years by those who know these things, that Cycle 25 would likely be a repeat of the poorly-performing Cycle 24, or even weaker. I think one thing  that can now be reasonably surmised is that this isn't another Cycle 24! We should know shortly, if Cycle 25 is the real thing or not, once the termination event has been confirmed.

In the meantime, enjoy the wide open strong signal opportunities now playing on 10m ... the band is back once again and in fine form ... way earlier than anyone ever expected!


 (1) Scott W. McIntosh (1), Sandra C. Chapman (2), Robert J. Leamon (3,4), Ricky Egeland (1), and Nicholas W. Watkins (2,5,6)

1 National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307, USA.
2 Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL, UK
3 University of Maryland, Department of Astronomy, College Park, MD 20742, USA.
4 NASA Goddard Space Flight Center, Code 672, Greenbelt, MD 20771, USA.
5 Centre for the Analysis of Time Series, London School of Economics and Political Science, London WC2A 2AZ, UK 

6 School of Engineering and Innovation, STEM Faculty, The Open University, Milton Keynes, UK

Wednesday, 18 November 2020

Hunting For NDBs In CLE262

ZYC-254 courtesy:
It's CLE time again!'CLE's are 'Co-ordinated  Listening Events, and NDB DXers around the  world focus their listening time on one small slice of  the NDB spectrum.
 This time the hunting ground is in two ranges: 240.0 - 259.9 kHz  plus  420.0 - 439.9 kHz

Propagation on MF has been excellent this past week and hopefully will continue to be good.

A challenge target for listeners in North America is ZYC - 254kHz in Calgary, Alberta. It's widely heard throughout North America thanks to its lower than usual modulation frequency. Listen for ZYC's upper sideband on 254.361 kHz with your receiver in the CW mode.

When tuning for NDBs, put your receiver in the CW mode and listen for the NDB's CW identifier, repeated every few seconds. Listen for U.S. NDB identifiers approximately 1 kHz higher or lower than the published transmitted frequency since these beacons are modulated with a 1020 Hz tone approximately.

For example, 'AA' near Fargo, ND, transmits on 365 kHz and its upper sideband CW identifier is tuned at 366.025 kHz while its lower sideband CW ident can be tuned at 363.946 kHz. Its USB tone is actually 1025 Hz while its LSB tone is 1054 Hz.

Often, one sideband will be much stronger than the other so if you don't hear the first one, try listening on the other sideband.

Canadian NDBs normally have an USB tone only, usually very close to 400 Hz. They also have a long dash (keydown) following the CW identifier.

All NDBs heard in North America will be listed in the RNA database (updated daily) while those heard in Europe may be found in the REU database. Beacons heard outside of these regions will be found in the RWW database. These databases have recently been re-vamped and are slicker than ever before!

From CLE coordinator Brian Keyte (G3SIA), comes the following CLE info:

Hello all,

This coming weekend we have another chance to forget the current problems for a while and enjoy a Coordinated Listening Event. 
All CLE logs will be very welcome, short or long.      

    Days:    Friday 20 Nov. - Monday 23 Nov.
    Times:   Start and end at midday, local time at the receiver.
    Normal NDBs in the ranges:                            
                     240.0 - 259.9 kHz  plus  420.0 - 439.9 kHz
                         (BOTH ranges are for ALL listeners)

Please log the NDBs you can identify that are listed in the ranges, plus any
UNIDs that you come across there.

You can find details of the beacons in those ranges, lists and maps, if you
go to  and click on the 'CLE SEEKLIST'

Send your final CLE log to  with CLE262 and FINAL in the
email title.  
Please show on EVERY LINE of your log:

  #   The full Date (or Day no.)  e.g. '2020-11-20' (or just '20')
        and UTC (the day changes at 00:00 UTC)
  #   kHz (the beacon's nominal published frequency if you know it)
  #   The Call Ident.

Other optional details - Location, Distance, etc. - go LATER in the same line (or in footnotes). Please make your log useful to old and new members alike by ALWAYS including your own location and brief details of the equipment and aerial(s) that you were using.

We will send an 'Any More Logs?' email at about 20:00 UTC on Tuesday evening so you can check that your log has been found OK.

To be included in the combined results your log must have arrived by 09:00
UTC on Wednesday 25 Nov. at the very latest.

We hope to complete making the Combined Results within a day or two.

Good listening
   Brian and Joachim
From:      Brian Keyte G3SIA       ndbcle'at'
Location:  Surrey,  SE England    (CLE coordinator)

  If you are interested in some remote listening - maybe
  due to local difficulties - you could use any one remote
  receiver for your loggings, stating its location and with
  the owner's permission if required.
   ( e.g. see )
  A remote listener may NOT also use another receiver,
  local or remote, to make more loggings for the same CLE.

These listening events serve several purposes. They

• determine, worldwide, which beacons are actually in service and on-the-air so the newly-re-vamped Rxx online database can be kept up-to-date

• determine, worldwide, which beacons are out-of-service or have gone silent since the last CLE covering this range

• will indicate the state of propagation conditions at the various participant locations

• will give you an indication of how well your LF/MF receiving system is working

• give participants a fun yet challenging activity to keep their listening skills honed

Final details can be found at the NDB List website, and worldwide results, for every participant, will be posted there a few days after the event.

The NDB List Group is a great place to learn more about the 'Art of NDB DXing' or to meet other DXers in your region. There is a lot of good information available there and new members are always very welcome. As well, you can follow the results of other CLE participants from night to night as propagation is always an active topic of discussion.

You need not be an NDB List member to participate in the CLEs and all reports, no matter how small, are of much value to the organizers.

Remember - 'First-time' logs are always VERY welcome!

Reports may be sent to the NDB List Group or e-mailed to CLE co-ordinator, Brian Keyte (G3SIA), whose address appears above. If you are a member of the group, all final results will also be e-mailed and posted there.

Please ... give the CLE a try ... then let us know what NDB's can be heard from your location! Your report can then be added to the worldwide database to help keep it up-to-date.

Have fun and good hunting!