Sunspot Index and Long-Term Solar Observations (SILSO) in Belgium said this month that the minimum between Solar Cycles 24 and 25 “most probably” took place last December. SILSO, a part of the Royal Observatory of Belgium and formerly known as SIDC, cited as evidence the January 2020 increase in the 13-month smoothed sunspot number — the first upswing since the Cycle 24 maximum in April 2014.
“[F]or now, this latest smoothed value in January 2020 is the very first point indicating a rise of the activity. So, the date of the minimum still needs a full confirmation over the coming months,” SILSO said on its website. “For now, preliminary smoothed values, limited to less than 13 months, hint at increasing values over coming months. If the rising trend indeed continues, this [December 2019] date will become fully definitive.”
SILSO said another indication of the transition between the two solar cycles can be drawn from counting individual sunspot groups that belong to either the old or new solar cycle. “While most sunspot groups belonged to the last solar cycle [Cycle 24] until September 2019, the dominance switched to groups of the new cycle in November 2019,” SILSO said.
SILSO said that in terms of the number of active regions, the minimum between Cycle 24 and Cycle 25 falls in October 2019. “This is close to December 2019,” SILSO said. It attributes the difference to three factors:

- The sunspot number also takes into account the total number of spots, and thus the size of the emerging active regions.
- The time of the minimum depends on the respective trends of the declining phase of the past cycle, and of the rising phase of the new cycles, over the 12 months surrounding the minimum.
- The date of the minimum has a significant uncertainty range. Near minimum the activity hardly varies and is close to minimum during a few months. “The date of the minimum is thus always less sharply defined than the date of the maximum of the cycles, which are more sharply peaked,” SILSO explained.
- “This late-breaking upward trend is now expected to accelerate over the coming months,” SILSO predicted. “So be prepared for a more eruptive and interesting sun!”
SILSO is preserving the longest record of solar activity, which spans the last 4 centuries.
SOURCE:ARRL
Review
Flex Radio, SmartLink Demo and Intro to MultiFlex
“This will be a multi-part video that was recorded at Flex Radio HQ in Austin Texas, March of 2019. SmartLink version 3, featuring MultiFlex, is... Read more
Unboxing the BITX40 SSB QRP 40-Meter Kig
“I learned about the BitX-40 from Randy, K7AGE’s unboxing video and immediately placed an order. It arrived today a few weeks after I plac... Read more
W6LG Talks To David G4AKC Who Is Pedestrian Mobile In The UK
“Jim W6LG talks to G4AKC, David Starkie in England. David is Pedestrian Mobile running about 100 watts to a quarter wavelength long vertical mob... Read more
Yaesu FT-DX10 And Icom IC-7300, Side By Side Comparisons
“This is an unofficial side by side comparison of the 2 receivers while incorporating the noise reduction and filtering features of the two. I a... Read more
USING AN RTL-SDR AS A PANADAPTER WITH AN AUTOMATIC ANTENNA SWITCHER
In this video we’ll show you how to use your computer, SDR dongle and some free software to add a panadapter display to your older, non-display... Read more
Equipment
EXTRAFLEX BURY /.400″ – Low loss Coax Cable
EXTRAFLEX BURY /.400″ [10,3 mm / 0,405 inches Cable] WHY CHOOSE THIS CABLE: – The only 10,3mm coax that can be use bo... Read more
Yaesu FT-991 – Manual (PDF)
Download the PDF File from new YEASU FT-991 : user-manual-yaesu-ft-991-part-1 user-manual-yaesu-ft-991-part-2 Oficial Yaesu Web Site: LINK Read more
Ultra Wide-band Coverage SDR Receiver MK3
Ultra Wide-band Coverage SDR Receiver MK3 • Full coverage reception form 100KHz to 2GHz SDR • Independent antenna inputs for Shortwave and VHF • USB c... Read more
ACOM 1010 160-10m amplifier
FEATURES Easy operation. The plate-load True Resistance Indicator (TRI) is an ACOM innovation that provides quick and precise tuning, typically... Read more
Acom 600S – 600W solid state 160m to 6m Amplifier
FEATURES • 5″ (108x65mm) high resolution color display, 800×480 pixels, and 24-bits colors. • The final stage uses field effect (MOSFET) tr... Read more
Antenna
Mobile Antenna Model 100A-HP 3.2 to 29 MHz
Mobile Antenna Model 100A-HP When properly installed on your vehicle the Model 100A-HP will provide continuous coverage from 3.2 to 29 MHz with the su... Read more
JK Mid-Tri-40 2 Elements on 40M / 3 Elements on 20M/ 4 Elements on 15M / 5 Elements on 10M / 26 Foot Boom
The JK Mid-Tri has been designed for Hams looking for a Mid level, cost effective but high quality Tribander antenna. This Tri-Bander’s... Read more
Antenna Circular Polarization
“Space communication has forced the use of Circular polarization. The fundamental advantage of circular polarization is that all reflections cha... Read more
KE4PT and W4RQ Win the September QST Cover Plaque Award
The winning article for the September 2018 QST Cover Plaque award is “Small Gap-Resonated HF Loop Antennas” by Kai Siwiak, KE4PT, and Richard Quick, W... Read more
App - Mobile
RFinder – The World Wide Repeater Directory kicks BrandMeister up a notch. DMR without CodePlugs!
RFinder has worked with the DMR network Brandmeister to create new usability enhancements. The new dashboard just released includes coverage maps gene... Read more
MacLoggerDX HD for iPad
MacLoggerDX HD is an Amateur Radio application that monitors the spots from your favourite DX Cluster for DXing, Contesting or casual rag-chewing. It... Read more
RUMlogNG2Go for iOS version 3.3 now available
Thomas Lindner, DL2RUM, is happy to announce the availability of version 3.3 of his RUMlogNG2Go logger for the iPhone and iPad. RUMlogNG2Go can be do... Read more
RS-MS1A – Remote Control Android App
Ray Novak and George Thomas show you how to control the ID-51A with the RS-MS1A Android app. Read more
HF Beam Antenna Calculator for Iphone and Ipad
Antenna Calculator The Maidenhead & HF Beam Antenna is a useful utility to calculate the the Maidenhead LOCATION as well as HF Elements’ s... Read more