Stephen P McGreevy «Natural Radio» 1996 -

submitted on Thu, 2006-04-27 20:46. | | | | |

Welcome to the Realm of
Natural VLF Radio Phenomena
«The (very beautiful) Music of the Magnetosphere and Space Weather»

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«My favorite summertime listening site west of Lone Pine against the Sierra Nevada mtns. Picture shows the van antennas, the VLF antenna being on the rear of the van on the right. I caught a few whistlers the morning of 06 June 2005.» ~ Stephen P. McGreevy.

[Audio 100Kb] whis_1500z06jun05.mp3
Whistler 05 June 2005

[Audio 427Kb] saucer.mp3
Saucer

[Audio 424Kb] whistle1.mp3
Whistler I

[Audio 657Kb] whistle3.mp3
Whistler II

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Stardust Space Capsule Re-entry FM scatter 15 Jan '06

Cropped photo of Stardust Capsule re-entry taken by Earl Wilson of China Lake Astronomical Society. The camera used was a Sony F-707 at f2, exposure time 30 seconds beginning at 0957:30 UT, 15 January 2006, looking north from a location about 20 miles south-east of Lone Pine, California - the trail is seen crossing from Cepheus into Cygnus and then dissappears behind the Inyo Mountains. The star just to the left of the beginning of the trail is SAO 32862, in Cepheus - the elevation of the star was about 4.56 degrees as calculated by "THE SKY" astronomy software (refer to the SKYMAP images below). The following recording is of FM skip/scatter from the ionized trail of the Stardust Space Capsule, which re-entered over Crescent City, California to land via parachute at Dugway Proving Ground in Utah on 15 January 2006, the re-entry time period being within 0956 to 0959 UT (0156-59 pst). Touchdown onto the ground at the DPG, via parachute, was at 1010 UT.

[Audio 2824Kb] stardust15jan06.mp3

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Leonids Meteor Storm, 19 Nov. 2002

On 19 November 2002, the second year of a Leonids Meteor Storm, (the best being in '01), Earl Wilson and I journeyed to Centennial Flat, 30 miles to the south-east of Lone Pine, California (36.32N/117.73W) to view and record on film, videotape, and audio, this incredible event. I monitored 102.1 MHz on a sensitive Audiovox car radio in my camper-van connected to the van-antenna about 40 inches in length, adjusted for optimum reception match for this radio and the location of the van-antenna. The result is quite incredible - an almost constant pinging and bursting of FM-station receptions, with occasional "super bursts" of longer duration, all with the characteristic fluttery fading of Meteor scatter! (warning - file is over 11 MB / 23 minutes in duration). This LONG audio-file also begins with a 1027-1028 UT WWV time check and some chat (me) for the first minute.

[Audio 11232Kb] leonidsshowerpeak19nov02.mp3

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The morning of June 2nd 1996 in northern Alberta was fabulous! This particular location has proven to be great for supurb auroral-zone natural VLF radio field-recording - both on this particular morning and also during early August 2000. This series of (2-track mono) MP3 audio files exhibit a lovely sequence of nose-whistler, chorus and wavering-tone emissions recorded 02 June 1996, beginning at about 1100 UT (0500 MDT). Other audio files of this period are on the main audio files page.

[Audio 250Kb] ab696f22nosewhistwavtonchorus02junj96.mp3
Mixture of chorus, nose-whistlers, and wavering tones recorded between 1100 and 1115 UT (0500 to 0515 MDT) 02 June 1996. WR-4b receiver and 10 foot-tall copper-pipe e-field antenna.

[Audio 144Kb] ab696nwbnosewhist02jun96.mp3
A couple of excellent examples of high-latitude "nose whistlers" recorded at about 1400 UT (0800 MDT) 02 June 1996.

[Audio 640Kb] vlf_risers_inyo_11feb05_a.mp3
Cluster of weak upward-rising tones (risers) and subtle high-latitude phenomena (at about 0200 ut, 11 Feb 05) 640 KB, 128 kbps, 40 sec. Listen.

Earth's Natural ELF-VLF radio signals in the audio-frequency radio spectrum - the radio sounds of the magnetosphere and space-weather - were the first radio signals people had ever heard beginning in the 1880's on telephone lines. They are amazing and beautiful, and the variety to be heard is endless - I encourage everyone to listen to them!

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Sometimes, MP3 audio compression tends to make the impulse-noise sounds of lightning static sound a bit odd, especially if encoded into the MP3 format at less than 128 kbs rate - otherwise the VLF phenomena is reproduced faithfully.

The several receivers I used to make most of these audio-file recordings were a McGreevy WR-4b unit with a couple of 2 to 3 meter tall whip verticals attached to my camper/van you see in photos below; hand-held WR-3 receivers of various ages; two cross azimuth verticaly hung delta loops made of several turns of wire - used mainly in Canada for the STEREO recording expeditions in the summers of 1998, 2000, and 2001 employing a large-loop antenna receiving system design by Stephen Ratzlaff alongside a version of his design adapted for my McGreevy WR-4b receiver. Quite a few recordings are made on hikes using a few versions of the hand-held McGreevy WR-3 receiver.

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Many listeners to Natural VLF Radio note how the majority of these recordings of Earth's beautiful Natural VLF Radio sounds closely resemble biological/vocal sounds made by birds, frogs, whales, seals, etc. or sci-fi sound effects, you have to hear them to believe the variety and beauty...they are the sounds of "Space Weather"!

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Nose whistlers are called such because spectrograms of them look like human noses - falling and rising components occur at the same time.

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sources: spaceweathersounds.com, auroralchorus.com, physics.uiowa.edu, star.stanford.edu