R3 radio blackout 7:57 p.m. EDT January 5, 2023 | Hacker News Reader

R3 radio blackout 7:57 p.m. EDT January 5, 2023

swpc.noaa.gov

38 pointsgraderjs19 comments

According to the NOAA Space Weather scale[0], we get about 15 of these R3-severity events every year. Is this one notable in some way?

[0] https://www.swpc.noaa.gov/noaa-scales-explanation

I think it's just bringing attention to the sunspot and its effects, more info from spaceweather.com:

"NOAA forecasters have boosted the odds of an X-flare today to 30%. Earth-facing sunspot AR3182 has developed an unstable 'beta-gamma-delta' magnetic field that poses a threat for strong explosions. Shortwave radio blackouts and Earth-directed CMEs are likely this week"

It affects ionosphere, which is relatively low frequency by definition, most time under 50MHz.

In past, where lot of use of under 50MHz bands (most known now shortwave band), because of technology limitations.

Now, most critical usages are over 88-100MHz.

Even more, every smartphone/tablet and display, emit noise in under 50MHz band. Under 1MHz is just sacrificed to cheap electronics, using dc-dc converters, even properly designed/shielded, emit noise (and many examples are not properly designed/shielded).

Only amateurs and radio-astronomers still using shortwave band extensively. And they usually notice events, but nobody cares much.

Few years ago, I've hear about using shortwave for underground communication and geo-radar, but they by definition mostly underground and very high power, just don't see ionosphere disturbances.

Also one of cause of modern mostly line of sight communication usage - question of sharing frequencies.

- Short-wave are hard to share, because You could hear some guy at other side of Earth. LoS is by definition near invisible on other side, because of surface curvature.

To be strict, many objects reflecting waves - clouds, traces of planes, etc, but they are not very powerful.

Some people feel headaches when Earth ionosphere disturbances happen, but I have not hear good scientific explanation.

Most relevant I know, modern research found in mammals sensitivity to magnetic fields, so it is possible, it exists as rudiment in human, so not all sensitive.

These will be more common in the next few years as we enter solar cycle 25: https://wikipedia.org/wiki/Solar_cycle_25

"The general agreement in the scientific literature, holds that solar cycle 25 will be weaker than average. However, observations from 2020 to 2022, the first three years of the cycle, significantly exceed predicted values."

It affects ionosphere, which is relatively low frequency by definition, most time under 50MHz.

In past, where lot of use of under 50MHz bands (most known now shortwave band), because of technology limitations.

Now, most critical usages are over 88-100MHz.

Only amateurs and radio-astronomers still using shortwave band extensively. And they usually notice events, but nobody cares much.

Few years ago, I've hear about using shortwave for underground communication and geo-radar, but they by definition mostly underground and very high power, just don't see ionosphere disturbances.

Also one of cause of modern mostly line of sight communication usage - question of sharing frequencies.

- Short-wave are hard to share, because You could hear some guy at other side of Earth. LoS is by definition near invisible on other side, because of surface curvature.

To be strict, many objects reflecting waves - clouds, traces of planes, etc, but they are not very powerful.

Some people feel headaches when Earth ionosphere disturbances happen, but I have not hear good scientific explanation.

Most relevant I know, modern research found in mammals sensitivity to magnetic fields, so it is possible, it exists as rudiment in human, so not all sensitive.

What does this mean for life on earth?

Well, it's 4 days later and we're still here...

I suspect mostly this means some amateur radio operators were annoyed for a few hours.

Pretty much.

There was no CME associated with this flare, so it didn't cause any geomagnetic effects-- just HF radio interference. If you were trying to listen to your shortwave radio in Australia at the time, you might've been annoyed.

Nothing about this particular event is still impacting us now, although the same sunspot is still active and could produce another large flare or CME at any time. And there's another very active sunspot emerging from the far side of the sun now too.

I suspect the opposite. Solar activity opens paths in bands that otherwise won't DX. So while some or all of HF might close VHF and the lower end of UHF can open and do amazing things.

Aside from amateur radio this would also impact naval and aeronautical radio traffic, both civil and military. Alternatives are usually available (the vulnerability of HF to solar activity is built into the structure of such systems) so it's not a crisis, but it can interfere with people and sometimes a little interference is all it takes to mess things up.

I believe DX in this context means "long distance".

Yeah, more specifically, it usually is referring to radio signal propagating using some form of bounce off the ionosphere. Usually only relatively lower frequencies do this (these are unfortunately named "HF" for high frequency). The more the earth is bombarded by charged particles, the less transparent the ionosphere is to radio signals, so the more likely you are to get a bounce from higher frequencies.

There could be some impact to GPS as well.

Too high frequency. GPS relies on direct line of sight, and not bouncing signals off the magnetosphere. (This is generally true of all satellite communications)

The ionosphere does weird things to GPS signals as it gets charged up. Delays change based on angle of incidence.

A key part of receiver accuracy is the ionosphere model. If you ignore ionospheric effects your position is likely to only be accurate within about a kilometer.

IIRC these types of solar events can cause some turmoil and even change the size/shape of the atmosphere. That can change how long it takes the GPS signals to get to your phone, which can add noise to the trilateration calculations. Fancier receivers have some clever ways to mitigate that, but your average cell phone GPS chip may lose some accuracy.

Aviation uses HF as well, for communications with ATC on oceanic routes.

(Many airplanes on those routes now have satcom as well, though it's not a requirement.)

So hilariously true. Personal anecdote: Many years ago, I recall a solar flare hitting during the annual Field Day competition -- I was operating 14MHz phone in the afternoon, great conditions from my mid-west corn-belt location to both East and West coast. Then.... over a period of about 5 minutes it was like a door slammed shut, and there was nothing but noise on the 14MHz band, or any other band. After about a hour or so, I remember the noise level went down from "impossible" to merely "highly obnoxious" and I could barely eek out contacts with stations 50 miles away. 14 MHz is pretty much never NVIS. It took hours for the ionosphere to stabilize again.

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