Most of the below .WAV format audio files are 8-bit, 11.025 kHz sample rate giving a 0 - 5.5 kHz bandwidth. A couple are sampled at 22.050 kHz giving a 0 - 11 kHz bandwidth. The original ground-based recordings I made are higher quality. Receiver used is a McGreevy WR-4b unit with 3 meter whip vertical attached to my camper/van. (For receiver information, refer to: WR-3/3E VLF receiver information).
You can also view several spectrograms of the associated audio files via link underneath the heading of the associated sound file. Previously I had these spectrograms as embedded images, but loading time for this web page became too long. These spectrograms were made via Gram 2.3.
Many listeners to VLF 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)...
Beautiful full-sky aurora in Manitoba, Canada on the night of 28-29 August 1996. Photo by Stephen P. McGreevy
Located 45 miles south-east of Flin Flon, Manitoba, this is one of the very best areas for aurora watching and Natural VLF Radio monitoring during the late summer
This is just a tiny sampling of the huge variety of emissions I recorded on each of those 13 days there.
23 August 1996 - 1545 UTC. Beautiful and loud chorus risers along with low-pitched "roaring" hissband - spectacular recording: 23a1545.wav, 347300 bytes, 31 sec.
23 August 1996 - 1505 UTC. Long-duration chorus risers along with low-pitched "roaring" hissband - spectacular recording: 23a1505.wav, 413K, 37 sec.
23 August 1996 at 2228 UTC - Spectacular "nose-whistler" along with hissband and triggered upward-rising emissions similar in sound to bird calls. This whistler had sustained echo-trains and many of them are audible in this recording, along with its initiating lightning static burst! 23a2228.wav, 40 sec., 442656 bytes
Spectrogram of 23 August - 2228 UTC recording
24 August 1996 at 1500 UTC -More and LOUDER low-pitched whooping and hooting tonal emissions of 1 kHz or less, mimicking "ghostly-tones" and very-weak background low-pitched roaring hissband. One of my favorite segments! 24a1500.wav, 14 sec., 161140 bytes
Spectrogram of 24 August - 1500 UTC recording
Spectrogram of 25 August - 1700 UTC recording
27 August 1996 at 1545 UTC - Very low-pitched chorus risers and "hooks". Quite nice sounding. As this type of chorus is rarer than higher-pitched chorus, I find this more exciting to hear and record! 27a1545.wav, 16 sec., 177588 bytes
28 August 1996 at 1334 UTC - More typical. sounding chorus, but this event was quite vigorous and loud due to another major magnetic storm occurring at this time. 28a1334.wav, 10 sec., 108508 bytes
28 August 1996 at 1637 UTC - Beautiful high-pitched chorus train, low-pitched roaring hissband, and a nice pure-tone riser toward the end of this sample. 28a1637.wav, 9.5 sec. 104188 bytes
30 August 1996 at 1432 UTC - Eerie very-low-pitched sounds of chorus risers, some of them quite loud. This is considered "polar chorus" as it is exceedingly rare to hear at latitudes away from the auroral zone. It is received most strongly inside the auroral zone. 30a1432.wav, 31 sec., 347790 bytes
Spectrogram of 30 August - 1432 UTC recording
Spectrogram of 30 August - 1652 UTC recording
Spectrogram of 02 June 1996 - 1030 UT Alberta recording
21 September 1996 in northwestern Nevada's Black Rock Desert - van and rear door-mounted WR-4b VLF receiver antenna.
22 September 1996 - 1430 UT - Moderately strong Dawn Chorus and fairly light static. n22s1430.wav, 28 sec., 303548 bytes
19 April 1996 - 2358 UT - VERY STRONG whistler (and also a weak one) in light static. RECORDED 45 MILES NORTHEAST OF RENO, NEVADA (at Nightengale VLF Camp) n19a2358.wav, 29 sec., 296.4 KB
Spectrogram of strong 2-hop whistler (and a weaker one) recorded in northern Nevada on 19 April 1996 at 2358 UTC
Spectrogram of the two, quite strong 2-hop pure-tone whistlers with weaker echoes recorded 6 miles west of Lone Pine, California 09 March 1997, 0420 UT
23 September 1997 - 1115 UT - A fairly strong near-pure tone whistler accompanied by a more diffuse/hissy multipath whistler, and then followed by a triggered emission which goes upward in pitch. Weak echo of pure whistler afterward. Inititing lightning static at start of recording. Taped 6 miles west of Lone Pine, California (WR-4b VLF receiver) 23se1115.wav, 4.7 sec., 102565 bytes (8 bit/22 kHz)
Spectrogram of the sound-file above allowing visual analysis - recorded 6 miles west of Lone Pine, CA 23 Sept. 1997, 1115 UT
WR-4B receiver control box and Marantz PMD-221 pro. cassette recorder in Manitoba
ELECTRIC ENGMA: The VLF Recordings of Stephen P. McGreevy
http://www.ibmpcug.co.uk/~irdial/vlf.htm or direct your inquiries to this e-mail address: irdial@irdialsys.win-uk.net
In January 1986, Sheldon Remington and I embarked on a 10-day camping and Longwave/Mediumwave DXpedition to Kauai, Hawaii. Camped one night about 5 miles north-east of Poipu, Kauai on the south-eastern coast of the island, I was scanning the 160-190 kHz "LowFER Band" and caught this record-breaking DX distance reception of Michael Mideke's Z2 beacon on 165.67 kHz located 9 miles north-west of San Simeon on California's Central Coast.
Initial reception was on a broadband Realistic DX-200 using a 50 foot wire into a Yaesu FRT-7700 tuner and homebrew LF/MF preamp. I had built into this tuner. The time of reception was at 0711 UT on 21 January, 1996; 9:11 p.m. Hawaiian Time.
This reception broke the standing LowFER DX record. Path length was a bit over 2450 miles.
This brief section of tape has been digtized and then FTT filtered to emphasize (+15 dB) the Z2 ident (about 2-3 wpm) at approx. 460 Hz pitch. A 15th harmonic of the Omega-C Oahu, Hawaii 11.05 kHz pulse is heard about 90 Hz higher in pitch at approx. 165.76 kHz which has been FFT-filter reduced 15 dB in loudness.
The following (edited for brevity) account by Michael Mideke was written in the mid-February 1986 Western Update #25:
"Sheldon Remington and Steve McGreevy spent several successful days demonstrating that the islands are indeed a good place for LF signals. On the NDB band, they logged 340 beacons for 21 states, all Canadian provinces from Quebec westward, and 57 countries total. A very high percentage of all NDB's on the West Coast (of North Am.) were logged. Z2 was heard for about an hour from 2311 PST Jan. 20 (1986) With considerable QSB. Initial reception was on a broad Radioshack receiver! Distance on this path is something over 2450 miles. Other lowfers were not heard, primarily due to interference from (Russian) LW broadcast stations which are stacked up several deep on every channel. Z2 was lucky enough to be in the clear til around midnight (PST) when the splatter came roaring up on both sides, negating any possibility of weak signal copy.
Current in the Z2 antenna was 200 ma or less, Antenna was 30ft vertical with twelve 18-foot tophat elements atop a massive radial and rod ground system. I have not been able to review the tapes yet, but from the reports it appears that reception would have been possible at levels as low as 0.5 watt (input). Hopefully we will be able to undertake experiments in the future to confirm this. Employing hi-tech options it should be possible to close the path with 0.1 watt or less! Such are the virtues of an over-water path. Can we make 3 hops next season (Z2 to Kauai is 2 E-layer skip hops-SpM)???" Michael Mideke, San Simeon, California, February 1986.
E-MAIL: vlfradio@triax.com
Web servers wanted!: If you enjoy these sound files and agree more Web server space is needed to have a greater and greater number of natural VLF radio sound files available to the world's radio and scientific community, I would like to know if you would join in and offer web server space for more natural radio sound files. Links to your own Web site(s) would be included in a new (proposed) section on this document or a separate page.
Secondly, this would serve as a growing repository for YOUR own recorded sound files, as more people are able to make their own recordings from their WR-3E receivers, and so forth.
Please e-mail me to get involved. Thanks to all of you in advance!
Updated 27 Sept. 1997 at Lone Pine, California, USA by Stephen McGreevy.