sunspot cycle - Page 1
Forum section: electronics / rf-microwave

author: m3vuv
author_rank: Super Contributor
timestamp: November 06, 2021, 09:18:57 pm
content: Hi all,havent done much radio recently but can anyone tell me at what part of the sunspot cycle we are at nowadays,ie just leavin one or just entering midway etc? tia.

author: Gyro
author_rank: Super Contributor
timestamp: November 06, 2021, 10:14:12 pm
content: I think we're heading towards a maximum aren't we? There was an aurora the other night that was visible as far south as Devon.Edit: Make that heading out of a minimum...https://www.swpc.noaa.gov/products/solar-cycle-progression

author: bob91343
author_rank: Super Contributor
timestamp: November 07, 2021, 12:08:28 am
content: I find this sunspot cycle stuff amusing. We have been on the way up for several years now, and not a whole lot has changed. I may sound like a flat earth guy but it does seem to me that if there ever was a sunspot cycle it has paused before a fresh start. Its effect on radio propagation also appears to be tenuous.I have a tried and proven method for determining the condition of the HF bands. I turn on the radio and see what signals are coming in and that tells me all I need to know. All the gurus analyze what little data there are, and prognosticate changes that seldom come about, especially given the lack of science here.Just some musings about DX. In case anyone cares, I have antennas for all the HF bands except 60 meters, and have worked well over 330 entities. Almost entirely SSB and CW. I don't chase awards and I don't mess with contests enough to matter and I don't send QSL cards. It's enough for me to know I can contact everywhere there are active hams.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: November 07, 2021, 02:01:17 am
content: I have been doing digital FT8 over the last 9 months and the bands above 20 m are getting better. I have picked up long range signals over the pacific on 17 and 15 m.Look at this graph. The F10.7 is the 10.7 cm flux from the sun which corresponds with sunspot activity. It's starting to trend. The red line is the number of sunspots.

author: 0culus
author_rank: Super Contributor
timestamp: November 07, 2021, 03:27:13 am
content: Quote from: bob91343 on November 07, 2021, 12:08:28 amStaying up with space weather is pretty important if you depend on HF radio links. For instance, a couple weeks back we had an X1 class flare that significantly elevated X-ray flux, which can cause significant dropouts. Even if you don't depend on HF links, space weather is pretty interesting because it directly affects the earth-ionosphere waveguide structure. YMMV.

author: bob91343
author_rank: Super Contributor
timestamp: November 07, 2021, 05:19:03 pm
content: Oculus, notwithstanding your comment about flares, that's a different topic from sunspots, I think. The OP was referring to the supposed link between some sort of cyclic pattern of sunspot count and HF propagation. I have watched this stuff with casual interest because it would be convenient to see a link. But I don't. The comparison between the amazing propagation we saw a few decades back and today cannot be attributed to sunspots. At least, I don't see it.

author: 0culus
author_rank: Super Contributor
timestamp: November 08, 2021, 02:04:50 am
content: Quote from: bob91343 on November 07, 2021, 05:19:03 pmSunspot activity has a direct causal effect with space weather, which in turn affects the ionosphere. Whether it has the effects we think it does on propagation? I don't know. Probably could argue it both ways.My point was that interest in space weather isn't useless.

author: bob91343
author_rank: Super Contributor
timestamp: November 08, 2021, 03:30:18 am
content: I realize the chain of cause and effect isn't clear or well defined, and that was my point. The OP wanted to know where we are in the current cycle, presumably to get an idea of what to expect on the HF bands. Unfortunately, that appears to be a simplistic approach. If someone can give him useful information, please include me in the loop, but this appears to be less than a science.I have read a lot on this, all the way back to Terman's Radio Engineering. Perhaps then there was a simple enough relationship, or maybe it was coincidental. Ensuing decades of data have almost debunked the classical approach.Yes, space weather is an important aspect. But again, there appears to be no solid link on which to predict propagation.

author: mark03
author_rank: Frequent Contributor
timestamp: November 10, 2021, 04:56:44 am
content: What a bizarre thread.First of all, if you'd like to know where we are in the sunspot cycle, why not google it? Posting here is like asking us if anyone knows when the next full moon will be.And second, I'm not sure how the third poster has missed the obvious and direct correlation between sunspot number and HF radio propagation. There's not a lot of mystery here. Sunspot count is directly correlated with 10.7cm flux, which in turn is directly correlated to MUF (max usable frequency). If you doubt this, perhaps you are drawing your impressions of solar activity from the general news media instead of actual data? Solar flares, etc. are a classic "slow news day" staple, so you really can't expect to know what is going on unless you check in with the experts. In the US that would be NOAA's Space Weather Prediction Center.

author: coppercone2
author_rank: Super Contributor
timestamp: November 10, 2021, 05:05:45 am
content: Well I can see his trepidation about a sunspot cycle because its a giant chaotic fusion reaction in space. Being able to understand what the hell is going on in a giant fireball based on a 11 year clock seems somewhat cavalier.From what I understand its not like we have some complex plasma resonator model of the sun (you know, like fluid simulations) that we use to get this information but more like an almanac. Until the underlying process is well understood I completely understand where Bob is coming from. I too have doubts about a object like the sun having such a regular pattern given what goes on in there.You would probobly need an orbital satellite network orbiting it, much like the earth, to make up some kind of weather report with predictions based on projected flow behaviors and distributions rather then make a prediction made by recursive knowledge.I mean look at whats going on there. You have a right to be baffled. You would think it to be completely random. If you knew nothing about the sun and you saw those pictures you would just think 'no way that thing has a pattern'. To me it seems kind of like predicting when a piece of boiled food will come to the top of the pot. Sometimes I swear I noticed there to be a kind of cyclic pattern with say.. a single large ravioli surfacing in boiling water in a regular interval, but its more like bobbing up and down then anything else. Maybe it has some drag forces on it based on the shape that the bubbles make it 'circle' around the pot too (like paper in the wind)... so if sunspots are kind of like that, I can imagine there being a 'reason' why they happen in a predictable fashion like we seem to say they do.I have also seen stupid stuff like plastic bags outside caught between apartment buildings (the [ shaped ones that have a kind of 'court yard' with fire escapes and such) getting stuck in a timed 'orbit' near a building corner.. kind of hypnotic actually. You would think it would get stuck on a wall or something but instead it dances around in a vortex endlessly. Then that makes me think of like a insulation* column forming in the plasma.. to some how explain how its a cold spot on the sun. how about we call them cool areas on the sun*more like area of solar material that has reduced thermal conductivity due to magnetic field bias, so I guess EE would call it a Hi-mu zone, rather then a sun spot. sounds like it should be on murata.com lol

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 10, 2021, 05:47:20 am
content: There are many things going on with the sunspot cycle. It isn't as simple as cranking the gain knob up and down on a amplifier.There is an eleven year cycle in sunspot activity. And several other longer term cycles have been at least tentatively identified. But these cycles are statistical trends with very noisy data.Sunspots are directly correlated with flare activity and ejections. They tend to be bigger and more frequent during peak sunspot years. But again it isn't one to one. Lots of noise in the connection.And finally, and probably the biggest piece of the puzzle is that these ejections are directional and somewhat randomly oriented. Almost always close to the planetary plane, but since the sun spins rapidly relative to a year they are well distributed around earths orbit. Only the ones which are aimed at our current location play with the ionosphere, though the aim doesn't have to be perfect. They spread out a lot on the way out to our orbit.So there is definitely a statistical trend towards an eleven year propagation cycle, but that by no means guarantees a readily seen effect in any one cycle.

author: mark03
author_rank: Frequent Contributor
timestamp: November 10, 2021, 06:22:03 am
content: Solar flares and ejecta (CMEs) are not the primary drivers of HF propagation---solar UV emissions are, and these are strongly correlated with sunspot number and the 11-ish year cycle.Solar flares do cause temporary radio blackouts, but those are the exceptions, blips in the longer-term cyclic variation in MUF.

author: mikerj
author_rank: Super Contributor
timestamp: November 10, 2021, 08:02:08 pm
content: Quote from: coppercone2 on November 10, 2021, 05:05:45 amThe 11 year cycle of sunspot activity has been measured going back to the 17th century, and we now know this coincides with the sun's magnetic field changing it's polarity. It's one thing to doubt the effects of solar minimum/maximum on e.g. radio propagation, but denying it even happens is flat earth territory.

author: coppercone2
author_rank: Super Contributor
timestamp: November 10, 2021, 10:03:19 pm
content: I am not debating if its considered predictable, just that it appears extremely chaotic and its natural that people are distrustful of such a object being an accurate clockLike I and most people know about the atmosphere and orbits to understand WHY seasons change (not to mention we are born with instinct on the matter). When you try to imagine why a fire ball has a 11 year clock built in you go wtf, the only repeatable plasma behavior we see are really fast clocks. anything that takes 11 years is gonna be funky. since it takes 11 years and the mechanism requires complex MHD simulation to model you might start to think if there are underlying factors which can cause the clock period to change in a way that we have not seen. 300 years = 30 data points. That is not a lot compared to what most other sciences get, and the cause-effect relationship is alien and downright complicated to many systems we find familiar.I now wonder if they found star-spots on other stars using imaging techniques to see what the star spot cycle looks like in in different age starsI imagine its a related to a bunch star things that can be considered vaguely similar (in regards to modeling complexity and chaotic nature) to global warming, el nino, ocean currents, tectonic shifts, eruptions and so forth. The question is, if there is a equation that relates these kind of things to the sun spot, how stable are the factors and can a star runaway condition happen that can cause a big rapid shift in one of the parameters that effects the spot clock while otherwise not cooking us, changing the color of the sun or doing something obviously weird that would have clued us in from astrometric observation of foreign stars.I personally just see a video like the one I linked and feel a mixture of awe and confusion, which is obviously not something you want to feel about a clock. But it does seem like a very good power source that is at least not going to turn off.. meaning so long it does not explode or burn us we are ok (the reaction mechanisms feel nigh unstoppable)And to add to the confusion, for many people.. a lava lamp, which at least looks similar, is the definition of random number generator, rather then clock.https://en.wikipedia.org/wiki/Lavarand

author: ejeffrey
author_rank: Super Contributor
timestamp: November 11, 2021, 03:49:01 am
content: Quote from: coppercone2 on November 10, 2021, 10:03:19 pmThe Earth's weather is chaotic too but the northern hemisphere it is warmer in July than January and that is easily observed even if you don't know why.It's fine to not know about the sunspot cycle of course but being a sun spot cycle skeptic is just silly.