The Anvil Screamer
April 20 2014
This afternoon a developing electrical storm snuck up on my radio observatory without much preceding lightning or sonic thunder to warn me. I was inside, deep in my head working on a project when I started to hear the banshee howl of an "anvil screamer" through two of my radios at 22.6 MHz and 20.9 MHz. I have heard this phenomenon before in conjunction with an approaching storm before so I sprang into action and disengaged my antennas expecting a lightning strike to happen at any moment. It is possible I was directly under a highly charged anvil part of a lightning cloud.
This so-called "anvil screamer" was caused by a corona discharge on my antennas as small discharges occurred off of pointy objects ( grasses and cactus spines ) in the vicinity of the antennas due to a charge differential between the ground and the air. I did not get it together in time to look outside but my antennas might have been glowing violet blue in this moment with St. Elmo's Fire.
I was able to capture a one minute forty second radio recording which builds in intensity and frequency and then stops abruptly as I got my system unplugged and disconnected.
Luckily, no close lightning bolt struck, as I thought I was about to "meet my maker" so to speak. It was a close call in any case.
For reference see: St Elmo's Fire, corona discharge, Trichel pulses
The movie below is the audio recording passed through a radio spectrograph.