HF Blackout During the 10/14 Solar Eclipse

[Jonathan]

A class C solar flare occurred during 10/14 solar eclipse at around the same time which influenced the ionosphere along with the solar eclipse. Here is a GOES plot from that day:

A SID (sudden ionospheric disturbance) was observed on many of the VLF transmitters, including WWVB. At VLF, SIDs caused by solar flares cause an enhancement in propagation, showing an increased signal strength at the receiver. Conversely, these SIDs cause radio blackouts in HF.

A member of the VLF community noticed an HF blackout during the 10/14 solar eclipse that was caused by the solar flare. Here is the HF spectrogram, credit to Thomas Ashcroft of the VLF community:

You'll notice the time around the eclipse shows around 28 MHz. I'm curious to see if other bands were affected.

For accurate modeling of the eclipse with HF data, I believe this solar flare and radio blackout should be taken into consideration. I emphasize this because with LWPC modelling in VLF, it will have to be taken into account.

Jonathan

KC3EEY