Huge X8.7 flare erupts on the sun - 14th May 2024

At the moment, I pretty much have my HF radio on 28.1246 MHz USB all of the time listening for QSPR and QRSS signals on the 10m band. Over the last few weeks and months, I've noticed plenty of solar noise from flares erupting on the sun.

The vast majority of these hardly move the S meter on the radio, it's just that I can hear the increase in noise level. At 16:47 UTC on the 14th of May 2024, there was a huge burst of noise and when I looked, the S meter was up at S6.

The is shown in the audio spectrum display above with time moving from right to left. The sudden onset of the solar noise can be seen as a result of the flare on the sun.

I knew that this flare was a really big enough and sure enough when I checked later, it turned out to be X8.7 solar flare and the largest one so far for the the current solar cycle.

I posted on Twitter /X that a big flare had occurred and Chris, G4IFX in England noted that he had heard the same thing on the 50 MHz band.

Larry, VO1FOG in Newfoundland got a screen capture of the solar noise while listening at 92.3 MHz  so it was certainly broadband as expected.

It also resulted in a big radio blackout on the HF bands. The question now is if this will result in a big aurora in the next day or two? We'll have to wait and see.

Solar Noise on the 28 MHz band - 10th May 2024

10th May 2024: I had the radio turned on in the background this morning and I noticed a large burst of noise from the sun. I had the SpectrumLab software running since yesterday and I took this screen grab.

Just to explain the image above...

1) I was listening on 28.1246 MHz USB which is the 10m WSPR & QRSS frequency.

2) Around 06:42 UTC, a meteor burnt up about 100kms above the west of England or Wales leaving an ionised trail behind. This lasted long enough that I was able to hear some of the QRSS signals from stations to the east of London, about 600kms to the east of me. The signals lasted for about a minute.

3) At about 06:43:30, the noise from a solar flare erupting on the sun reached the Earth and I heard the burst of solar noise as a loud hissing sound on 28 MHz. You can see this as the brighter colour in the image. It then faded slowly with some minor peaks over the next few minutes.

I later checked the NOAA website in the US and sure enough, there was a peak in the GOES X-Ray flux at about the same time. Link - https://www.swpc.noaa.gov/products/goes-x-ray-flux

It looks as if it was a X3.9 burst from the sunspot group AR 3664.

Maximum 10 May 2024 06:54:00 GMT X3.9 Integrated flux: 4.4e-1 J m-2

I often hear solar noise on the 28 MHz band but this one was a bit stronger than usual.

Solar noise detected on 28 MHz after X1 flare on the sun - 28th Oct 2021

Thursday 28th October 2021: I spent most of the day listening for WSPR signals on the 28 MHz but it was pretty poor mainly due to a lack of WSPR signals.

The big surprise during the day was the large burst of solar noise on the band in the afternoon. This sounded like a loud hissing sound and it was spread across the band. 

Solar noise has a softer kind of sound as compared to electrical interference and it rises and falls in amplitude whereas electrical noise tends to be on/off.

The solar noise got up as high as S8 at one stage which is way above my usual noise floor of S1-2. It was so pronounced that I wrote down the time... 15:28 UTC.

I checked the X-Ray flux later in the day and sure enough, a big X1 flare had gone off on the sun at the same time I heard the solar noise.

You will notice from the image at the top of the post that the flare is pointing right at Earth. It's likely that the material ejected from the sun will reach the Earth this weekend resulting in possible auroral conditions and making a mess of the HF bands in general.

Update: The material is likely to impact the Earth after 21:00 UTC on the Saturday the 30th of October which will be almost in the middle of the CQWW SSB contest. The overall impact will be dependent on the magnetic polarity of the incoming material.

Video: Space weather physicist Dr. Tamitha Skov has a lot more detail about the event below...

Solar Noise detected at 40 MHz - 22nd May 2021

Early on the morning of the 22nd of May 2021, I was listening for some aircraft scatter signals on the 40 MHz band when I noticed a sudden onset of solar noise as shown above.

This sounds just like a hissing sound but the intensity comes in waves. It's not like say interference you might get from an electrical source which is very much on or off. Solar noise is a gentle hiss that rises and falls in intensity, a bit like waves would do as they crash on a beach.

The waterfall display above shows the event starting around 06:48 UTC and finishing at 06:54 UTC. As soon as I was sure it had finished, I checked the Space Weather Prediction Center website and sure enough, there was a solar flare that matched what I had heard.

I later heard the same effect on 28 MHz while I was listening for WSPR signals and my Twitter feed had lots of tweets about solar flares and solar storms.

It seems to me that the 40 MHz band is a good choice for monitoring noise from the sun. It's high enough in frequency that it's above all of the usual F2 layer propagation and the antennas can be large enough to capture a lot of noise.

Solar noise detected on 28 MHz?? - Wed 20th March 2019

Wednesday the 20th of March 2019 seemed like just another pretty quiet day on 28 MHz with just a handful of FT8 signals heard on the band. This morning however while I had the radio on in the background monitoring the FT8 frequency of 28.074 MHz, I noticed a sudden increase in the background noise level. It wasn't huge but it was enough that I made of note of the time....11:20am (11:20 UTC).

Later I checked the SolarHam website and sure enough, there seems to be a spike around that time as can be seen on the chart above.