<p dir="ltr">Este fim de semana nos 12m (24mhz) foi um "forrobodó" o dia todo!</p>
<p dir="ltr">73's de CT1GFQ<br>
Carlos Fonseca<br>
SKCC #466C <a href="http://www.skccgroup.com/">http://www.skccgroup.com/</a><br>
REP #1406 <a href="http://www.rep.pt">http://www.rep.pt</a></p>
<div class="gmail_quote">No dia 05/05/2014 13:16, "João Costa &gt; CT1FBF" <<a href="mailto:ct1fbf@gmail.com">ct1fbf@gmail.com</a>> escreveu:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Anvil Screamer: corona discharge pulses - spectrograph<br>
<br>
Thomas Ashcraft has released a recording made at his shortwave radio<br>
observatory of a corona discharge on 20.9 and 22.6 MHz<br>
<br>
The Vimeo description reads:<br>
<br>
This afternoon a developing electrical storm snuck up on my radio<br>
observatory without much preceding lightning or sonic thunder to warn<br>
me. I was inside, deep in my head working on a project when I started<br>
to hear the howl of an "anvil screamer" through two of my radios at<br>
22.6 MHz and 20.9 MHz.<br>
<br>
I have heard this phenomenon before in conjunction with an approaching<br>
storm before so I sprang into action and disengaged my antennas<br>
expecting a lightning strike to happen at any moment. It is possible I<br>
was directly under a highly charged anvil part of a lightning cloud.<br>
<br>
This so-called "anvil screamer" was caused by a corona discharge on my<br>
antennas as small discharges occurred off of pointy objects ( grasses<br>
and cactus spines ) in the vicinity of the antennas due to a charge<br>
differential between the ground and the air. I did not get it together<br>
in time to look outside but my antennas might have been glowing violet<br>
blue in this moment with St. Elmo's Fire.<br>
<br>
I was able to capture a one minute forty second radio recording which<br>
builds in intensity and frequency and then stops abruptly as I got my<br>
system unplugged and disconnected.<br>
<br>
Luckily, no close lightning bolt struck, as I thought I was about to<br>
"meet my maker" so to speak. It was a close call in any case.<br>
<br>
Listen to the recording at<br>
<a href="http://vimeo.com/93097274" target="_blank">http://vimeo.com/93097274</a><br>
<br>
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<br></blockquote></div>