GCN Circular 32745
Authors: A. Guha (Centre for Lightning and Thunderstorm Studies (CeLTS), Department of Physics, Tripura University, India.), P. Nicholson (Todmorden, UK) We report the observation of a sudden disturbance of radio propagation in the very low frequency (VLF) band between 18kHz and 23kHz coincident with GRB221009A. Affected were phase and amplitude of MSK ("Minimum Shift Keying") signals from naval transmitters monitored by the Indian Lightning Detection Network. The GRB221009A exceeded 70 degrees elevation at all receiver sites. https://ildn.in/gallery/ILDN-GRB221009A-VTX3.png https://ildn.in/gallery/ILDN-GRB221009A-NWC.png https://ildn.in/gallery/ILDN-GRB221009A-NDT.png The Indian Lightning Detection Network (ILDN) is an experimental network of 10 VLF receivers operated by collaborating institutions for lightning location and observation of other VLF phenomena on the Indian subcontinent.