The guardian reports on the decline in HF noise signals as the pandemic spread. https://www.theguardian.com/science...read-around-world-during-coronavirus-pandemic
But to clarify this is NOT EMF HF noise, its vibratory (mechanical) AUDIO noise. In most urban areas like mine, lacking the usual din from rush hour traffic on nearby roads was easily if eerily noticed but welcome too.
"high frequency noise fell by 50% in the weeks before lockdown".... Please note that when SEISMOLOGISTS speak of " High Frequency" they are not talking about RADIO. For amateur radio, " High Frequency" spans 3 Megacycles through 30 Megacycles... which has naught to do with audio frequency and INFRA-Sonic compression waves sensed by seismographs.
