A research paper, "Overlapping Magnetic Activity Cycles and the Sunspot Number: Forecasting Sunspot Cycle 25 Amplitude," by Scott W. McIntosh, Deputy Director of the National Centre for Atmospheric Research in Boulder, et al., has concluded that Solar Cycle 25 could be among the strongest sunspot cycles ever observed, and will almost certainly be stronger than the just-ended Solar Cycle 24 (sunspot number of 116).
The scientists say it will also most likely be stronger than Solar Cycle 23 (sunspot number of 180).
(arrl)
From WIA news for 13 Dec 2020....
Edit note :
While Cycle 23 was pretty good from VK4, like working into the UK on 6M SSB a couple of times, something better that the 180 count from then could be very interesting for VHF DX, particularly given the improvements in the equipment used today : bandwidths, modes, transmit power and receiver performance. Contemplating FT8 (or successor) operation in 2025-2026 bears some planning.
Perchance, I went back to see what the count values from 1958 - the IGY - were like, the year(s) that blew all preconceptions about VHF DX-ing away. :
" Solar cycle 19 was the nineteenth solar cycle since 1755, when extensive recording of solar sunspot activity began. The solar cycle lasted 10.5 years, beginning in April 1954 and ending in October 1964. The International Geophysical Year occurred at the peak of this solar cycle. The maximum smoothed sunspot number (SIDC formula) observed during the solar cycle was 285.0, in March 1958 (the highest on record[3]), and the starting minimum was 5.1. During the minimum transit from solar cycle 19 to 20, there were a total of 227 days with no sunspots. This was the lowest number since 1850.
"
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Tad Cook, K7RA in an ARRL post to all radio amateurs asks "What happened? Solar Cycle 25 seemed well underway, but no new sunspots emerged since last year prior to Christmas, on December 23, 2020 to be exact. The last time any sunspot was visible was on January 2."
On January 14, the day prior to Tads post, Spaceweather.com posted, "Welcome back, solar minimum."
Average daily solar flux declined from 78.6 to 73.8. Geomagnetic A index remained quiet
BTW (But Then Wait)
A new study being reported on in universtoday.com suggests that Solar Cycle 25 may be more powerful than previously predicted.
It's the big question in wireless weather for 2021 and the new decade. Will Solar Cycle 25 wow observers, or be a washout? This new study goes against the consensus, suggesting wemay be in for a wild ride if predictions and analysis of past solar cycle transitions hold true.
The last Solar Cycle 24 was a historic under-performer, starting from early 2011 (based on the termination of Cycle 23). This lacklustre cycle produced a sunspot number of just 116, and featured year 2019 with over 281 spotLESS days (thats 77% of the year) for the Earthward face of the Sun, the longest dearth of sunspots in over century.
tinyurl.com/y5wq46z9
So, is propagation going to improve over the next 4-5-6 years or is Solar Cycle 25 going to be a proverbial 'dead dog' ??
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These "smart scientists" will never in a million years be able to forecast what the sun will do.
the sun will do what it jolly well likes.
What we need is at least 6 months of the SFI slowly going up, then keep going up for maybe 2 to 3 years, reach a peak then slowly come down again over 2 or 3 years.
That first 6 months is a must
If the 6 months does not happen all bets are off.
On a SFI scale of 66 to approx 350 SFI today flux of 76 is nowhere and just 10 above the rock bottom of 66
The site was compiled by VHF-UHF stalwart, Mike Farrell VK2FLR (SK).
I should note that some instances of the DX reported did not involve propagation affected by the solar cycle - F2, or transequatorial VHF propagation [TEP. See (a) http://home.iprimus.com.au/toddemslie/aTEP-Harrison.htm, and (b) http://home.iprimus.com.au/toddemslie/eTEP-Harrison.htm ]. Sporadic E propagation, Es (ee ess, not E's as in eaz) is largely unaffected by the solar cycle, except perhaps when extreme MUF is involved (e.g. 144 MHz and above).
An example is the ". . very rare appearance of the VK0GR beacon from Casey Base . . " This was a temporary 6m beacon during the early 1970s, built and installed in 1972 by IPS Radio & Space Services (later Space Weather Services). Distance is 4470 km. Propagation was most likely supported by a combination of mid-latitude Es and Polar Es. The growl on the signal (characteristic of auroral propagation) is caused by Alvfen waves in the ionospheric plasma. The first continental Antarctic 6m beacon was built and installed at Casey by yours truly in December 1970 (callsign: VK0GR). It ran a pair of 6146s in push-pull for 100 watts output to a 3-element Yagi.
Been visiting the web site at the US Space Weather Prediction Center ( https://www.swpc.noaa.gov/communities/sp...nthusiasts ) a bit lately and found some historical info about the last few solar cycles.. Image attached below.
To me, it might be a significant rise but I have doubts that it will be classified as "Strongest Ever" as per this thread's title.
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Got any photos of that VK0 beacon Roger? I'd sure like to see them. Nostalgia & all that. Ahh... "glass" technology... where the silicon was on the outside.
(30-01-2022, 04:10 PM)VK3PY Wrote: Got any photos of that VK0 beacon Roger? I'd sure like to see them. Nostalgia & all that. Ahh... "glass" technology... where the silicon was on the outside.
73,
Chas
VK3PY
Sorry, Chas. No photos of the beacon. It ran a pair of 6146s loafing along at 50 watts. I do have a circuit somewhere. I'll see if I can dig it out and post that here.
(30-01-2022, 04:10 PM)VK3PY Wrote: Got any photos of that VK0 beacon Roger? I'd sure like to see them. Nostalgia & all that. Ahh... "glass" technology... where the silicon was on the outside.
73,
Chas
VK3PY
Sorry, Chas. No photos of the beacon. It ran a pair of 6146s loafing along at 50 watts. I do have a circuit somewhere. I'll see if I can dig it out and post that here.
Hi Chas.
As I said above, I have no photos of the beacon, but the contemporaneous documentation I made at the time I built it throws up the circuit attached here.
(30-01-2022, 04:10 PM)VK3PY Wrote: Got any photos of that VK0 beacon Roger? I'd sure like to see them. Nostalgia & all that. Ahh... "glass" technology... where the silicon was on the outside.
73,
Chas
VK3PY
Sorry, Chas. No photos of the beacon. It ran a pair of 6146s loafing along at 50 watts. I do have a circuit somewhere. I'll see if I can dig it out and post that here.
Hi Chas.
As I said above, I have no photos of the beacon, but the contemporaneous documentation I made at the time I built it throws up the circuit attached here.
A thing of beauty, Roger. It should be hanging in the Louvre.
Those neutralising capacitor thingies must have been twitchy to adjust. I'm also pleased to see you used 0.01uF bypass capacitors. None of that 10nF rubbish!
Thanks Chas. Perhaps not the Louvre, but I'll take the compliment, anyway.
The neutralising capacitors were actually easy to adjust, I found, although fiddly. There's a technique for adjusting them that involves applying drive without PA plate+screen volts applied while measuring the PA output.
As for the 0.01 uF bypass capacitors, I used what was on-hand. I don't think 10 nF caps were made until the mid-late 1970s.
Thanks Graham. Seems like I "started something" with that VK0GR 6m beacon.
Nice recording of VK0CK (ex-VK5CK, David) on Macquarie Island, some 4200 km from you. Most likely to be 3 hops Es, as 2 hops would require antenna radiation patterns at or fractionally above zero degrees at each end, for Es at 100 km height.
Some interesting recordings on your website, too - I particularly liked your 3 watt mobile 6m TEP one.
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