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7 February 2021.
Masawir Soomaaliya 9 iyo Radiyo VLF
Listening to TLF, ELF and SHF Radio below 100 Hertz (100 Hz).
Listening from 0 to 3 Hz.
Listening from 3 Hz to 30 Hz.
Listening from 30 Hz to 300 Hz.
Listening from 300 Hz to 3 kHz.
Listening from 3 kHz to 30 kHz.
Listening below 22 kHz.
Listening below 30 kHz.
FREE VLF Radio Receiver.
Email from the USA.
Regarding an antenna for 22 Hz.
22 Hertz is in the ELF Extremely Low Frequency band.
25 July 2009
To- Somaliahamradio@yahoo.com
Sam,
I have been casting about the internet looking for someone with experience at Extremely Low Frequencies ELF.
I started looking for amateur radio discussions because, as a former ham, I knew that hams get into all sorts of odd things like this.
Specifically, I'm interested in detection at a frequency of 22 Hz.
Given that it is impractical to build an antenna for 22 Hz, what sort of things can be done to optimize receiver sensitivity at that low of a frequency?
Do you know, or do you know anyone would know how to approach an ELF antenna design like this?
Any leads you may be able to provide would be most appreciated.
Thanks
Bruce Girrell
(Former) WA3HPE in the United States of America.
Along the Galkayo to Garowe Highway in Somalia September 2007
Hello Bob and readers,
Firstly for our readers this question involves the frequency of 22 Hertz.
The location of 22 Hertz is in the ELF band of frequencies between the TLF and the SLF frequeny bands shown below.
The Radio spectrum (electromagnetic radio spectrum) from 0 to 3000 GHz.
TLF.
TLF Radio broadcasts to submarines at maximum depth.
TLF Tremendously Low Frequency 0 Hz to 3 Hz.
TLW Tremendously Long Wave radio wavelengths are more than 100,000 km (kilometres) long.
ELF.
ELF Radio broadcasts to submarines at near maximum depth.
ELF Extremely Low Frequency 3 Hz - 30 Hz.
ELW Extremely Long Wave radio wavelengths are 100,000 km to 10,000 km long.
SLF.
SLF Radio broadcasts to submarines at depth.
SLF Super Low Frequency 30 Hz - 300 Hz.
SLW Super Long Wave radio wavelengths are 10,000 km to 1,000 km long.
ULF.
ULF Radio broadcasts to submarines near depth and underground mine radio broadcasts.
ULF Ultra Low Frequency 300 Hz - 3000 Hz. Submarine radio communications and Mine radio broadcasts.
ULW Ultra Long Wave radio wavelengths are 1,000 km to 100 km long.
VLF.
VLF higher data speed radio broadcasts to subsurface submarines and navigation radio signals.
VLF Very Low Frequency 3 kHz - 30 kHz.
VLW Very Long Wave radio wavelengths are 100 km to 10 km long.
LF.
LF Aircraft navigational Non Directional radio Beacons and Long Wave AM broadcasting in Europe, Russia and Africa.
LF Low Frequency 30 kHz - 300 kHz.
LW Long Wave radio wavelengths are 10 km to 1 km long.
MF.
MF local AM stereo radio broadcast band and medium range 2.4 MHz AM broadcasting across the outback in Northern Territory, Australia.
MF Medium Frequency 300 kHz – 3000 kHz.
MW Medium Wave radio wavelengths are 1 km to 100 km long.
HF.
HF worldwide radio communications and worldwide SW radio broadcasting.
HF High Frequency 3 MHz – 30 MHz.
SW Short Wave radio wavelengths are 100 m to 10 m (metres) long.
VHF.
VHF local FM stereo radio broadcasting, local digital radio broadcasting (introduced in Australia in 2009), local analogue television TV broadcasting (to be decommissioned in Australia in 2012), local digital television TV broadcasting and short distance two way radio communications.
VHF Very High Frequency 30 MHz – 300 MHz.
VSW Very Short Wave radio wavelengths are between 10 m to 1 m long.
UHF.
UHF Mobile telephone (Cell phone, mobile radio telephone, cell phone radio network), local digital radio broadcasting (introduced in Australia in 2009), local analogue TV television broadcasting (to be decommissioned in Australia in 2012), local digital TV television broadcasting and short distance two way radio communications.
UHF Ultra High Frequency 300 MHz – 3000 MHz.
USW Ultra Short Wave radio wavelengths are 1 m to 10 cm (centimetres) long.
Microwave frequencies are between 1000 MHz to 300,000 MHz (1 GHz to 300 GHz).
SHF.
SHF radio links to and from radio communications satellites connecting telephone and internet users on Earth.
SHF Super High Frequency 3 GHz – 30 GHz.
SSW Super Short Wave radio wavelengths are between 10 cm to 1 cm long.
EHF.
EHF Minimum Essential Emergency Communications Network MEECN USA includes radio satellite communications to submarines is under construction in 2009.
EHF Extremely High Frequency 30 GHz – 300 GHz.
ESW Extremely Short Wave radio wavelengths are 1 cm to 1 mm (millimetres) long.
THF.
THF SMW Radio Astronomy to study the Universe.
THF Tremendously High Frequency 300 GHz - 3000 GHz (0.3 THz - 3 THz).
TSW Tremendously Short Wave radio wavelengths are 1 mm to 0.1 mm (100 µm, 100 micrometres) long.
SMW Sub Millimetre Wave (Sub Millimeter Wave) band.
The purpose of an antenna for 22 Hz is to receive radio waves on 22 Hz.
22 Hz is in the 3 Hz to 30 Hz ELF band where radio waves (radio wavelengths) are between 100,000 km to 10,000 km long.
Anything we do will not be able to efficiently detect such signals because our antenna (in a normal suburban house) can never be near the ideal quarter wavelength (25,000 km long for a 3 Hz antenna to 2,500 km long for a 30 Hz antenna) or half the wavelength (50,000 km long for a 3 Hz antenna to 5,000 km long for a 30 Hz antenna).
However we don’t need high efficiency to be able to successfully hear signals in the ELF 3 Hz to 30 Hz band. Why?
To answer this question lets look at the use of the ELF band and the radio bands either side.
Frequencies below the ELF band are called the TLF Tremendously Low Frequency band from 0 Hz to 3 Hz.
Frequencies above the ELF band are called the SLF Super Low Frequency band from 30 Hz - 300 Hz.
The frequencies 0 Hz to 200 Hz that are within the TLF, ELF and SLF bands.
200 Hertz 200 Hz Max Planck Institute’s High Frequency (HF) heating facility, near Tromso (Tromsø), Norway. This research station transmits 1 MW (200 MW to 300 MW ERP effective radiated power) on 2.75 MHz - 4 MHz, 3.85 MHz - 5.6 MHz and 5.5 MHz - 8 MHz into the overhead ionosphere that results in the upper atmosphere generating electromagnetic emissions from 200 Hertz to 6.5 MHz which can be heard on the ground. This is used for the study of the Earth’s ionospheric and magnetospheric properties and as a way of using high power short waves to generate Super Low Frequency signals.
70 Hertz – 150 Hertz, 70 Hz – 150 Hz MEECN, USA. A Minimum Essential Emergency Communications Network MEECN development proposal suggested this frequency range for US Department of Defense communications to submerged submarines. MEECN is managed by the Naval Air Systems Command to improved USA capability to receive presidential directives throughout the full spectrum of a nuclear war.
In 2008 MEECN began work to add EHF to their network.
In 2008 the US Navy was using floating HF radio antennas and buoys that allowed two way communications with submarines.
A radio buoy can be launched from a submarine. When the buoy arrives on the surface it can contact a satellite by radio waves and in the water it can contact the submarine using sonar waves.
The problem with this system is that sonar waves indicate the location of a submarine.
The buoy is hidden if it operates below the Sea surface.
http://www.godfreydykes.info/OTHER%20SUBMARINE%20AERIALS.htm
ELF and EHF submarine communication systems.
82 Hertz 82 Hz ZEVS World wide SLF (“ELF”) broadcast station to Russian nuclear armed submarines, Kola Peninsula, Murmansk, Russia. Operational from the 1990’s and today (2009) using MSK (Minimum Shift Keying, Minimum Shift Carrier wave) communications from 81 Hz to 83.3 Hz.
76 Hertz 76 Hz WTF Wisconsin Transmitter Facility, World wide SLF (“ELF”) broadcast station to USA nuclear armed submarines, Clam Lake, Wisconsin, USA. When MTF became operational in 1989 WTF was renamed Naval Radio Transmitter Facility Clam Lake. WTF/NRTF Clam Lake was operational from 1985 to 2004.
76 Hertz 76 Hz MTF Michigan Transmitter Facility, World wide SLF (“ELF”) broadcast station to USA nuclear armed submarines, Republic, Michigan, USA. Operational from 1989 when both WTF and MTF synchronized their transmissions to provide improved broadcast coverage. MTF was operational from 1985 to 2004.
72 Hertz 72 Hz Royal British Navy, GlenGarry Forrest, Scotland, U.K. Proposed testing of a world wide submarine SLF (“ELF”) broadcast station. This project was cancelled in 1991 “in the light of current defence requirements.”
70 Hertz to 80 Hertz, 70 Hz to 80 Hz all USA submarines equipped with SLF radio receivers in 1990’s.
59.83 Hertz 59.83 Hz Schumann resonance overtone 8.
53.33 Hertz 53.33 Hz Schumann resonance overtone 7.
46.83 Hertz 46.83 Hz Schumann resonance overtone 6.
40.33 Hertz 40.33 Hz Schumann resonance overtone 5.
40 Hertz to 50 Hertz, 40 Hz to 50 Hz all USA submarines equipped with SLF radio receivers in 1990’s.
33.83 Hertz 33.83 Hz Schumann resonance overtone 4.
27.33 Hertz 27.33 Hz Schumann resonance overtone 3.
20.83 Hertz 20.83 Hz Schumann resonance overtone 2.
14.30 Hertz 14.30 Hz Schumann resonance overtone 1.
7.83 Hertz 7.83 Hz Schumann resonance fundamental resonant frequency of Earth’s spherical ionospheric cavity. This is the electro magnetic resonance between the surface of the Earth and Earth’s conductive ionosphere excited by lightning.
2.2 Hertz 2.2 Hz HAARP High Frequency Active Auroral Research Program, Gakona, Alaska, USA.
1 Hertz – 29 Hertz, 1 Hz – 29 Hz HAARP, High Frequency Active Auroral Research Program, Gakona, Alaska, USA. Research into communications for deeply submerged submarines.
1 Hertz 1 Hz Earthquake prediction research.
0 Hertz – 300 Hertz and above, 0 Hz to 300 Hz and above USA submarines equipped (today 2009) with TRF, ELF, SLF and the frequencies above.
In 2001 The Department of the Navy USA described the 76 Hz “ELF” (SLF) communications system “as the only operational communications system” (in the USA) “that can penetrate sea water to great depths and is virtually jam proof from both natural and man made interference…allowing the (USA) submarine fleet to remain at depth and speed and maintain its stealth while remaining in communications with the national command authority.”
The “ELF” (SLF) communication system (low data rate- slow speed transmission) can be used to tell a submarine crew to rise near the Sea surface to copy a VLF higher data rate (higher speed transmission) broadcast. If necessary an even higher data rate is available on frequencies from HF through to EHF.
The US Navy broadcasts to nuclear armed and nuclear powered submarines deep under the Pacific Ocean, Atlantic Ocean and the Arctic ice cap. The two “ELF” (SLF) stations in the USA were decommissioned in 2004).
A British “ELF” (SLF) nuclear submarine communication project at Glengarry Forest, Scotland was cancelled in 1991.
http://www.secretscotland.org.uk/index.php/Secrets/GlengarryForestELF
What knowledge can we gain from research done in the Super Low Frequency 30 Hz - 300 Hz band?
Firstly we know that submarines successfully get worldwide reception in that band.
Secondly we know they are not using antennas anywhere near a quarter or a half a wavelength long.
This shows it will be possible to get good results with an antenna in a suburban home location.
The USA 40 kHz to 80 kHz submarine broadcast and the submarine communications system before the decommissioning of both the Wisconsin ELF submarine broadcast station and the Michigan ELF submarine broadcast station in 2004 are outlined on this link http://www.fas.org/man/dod-101/navy/docs/scmp/part07.htm
Why did the USA decommission its two long operating 76 Hertz Seafarer US Navy submarine broadcast stations?
All information is good for researching an antenna for 22 Hz and this question cannot go unanswered because it may give more ideas on this question.
The USA concluded that in a nuclear attack their land based Super Low Frequency broadcast station would be the first to be attacked so as to cut their communications to their submarines that wait quietly for months at a time in the deep Pacific Ocean, Atlantic Ocean and under the Arctic ice cap. In this situation an early first strike nuclear attacker would not be worried about retaliation from submarines with nuclear missiles that had been the basis for a deterrent from an attack.
In 2009 the USA operates VLF Very Low Frequency 3 kHz - 30 kHz submarine land broadcast stations but those cannot reach deep under the Pacific Ocean, Atlantic Ocean and the Arctic ice cap.
A 5 MHz HF radio wave will penetrate about 0.12 metres (12 centimetres, 4.7 inches) into Ocean salt water.
Low Frequency LF radio waves of 100 kHz can only penetration to a water depth of about 7 metres.
Very Low Frequency VLF radio wave penetration of water depends on the amount of salt in the water. In the Atlantic Ocean where salt level is high VLF will penetrate not more than 20 metres below the Sea surface. In the Baltic Sea and Mediterranean Sea where the salt level is low it is possible for VLF radio signals to penetrate over 40 metres below the Sea surface.
In submarine radio broadcasts a 76 kHz Extremely Low Frequency ELF radio wave will penetrate between 90 to 120 metres (300 feet to 400 feet) below the surface of the Ocean salt water.
Submarine Tremendously Low Frequency TLF radio broadcasts on 2.2 Hz (2.2 Hertz) penetrate below the surface of the Ocean salt water more than 90 to 120 metres (300 to 400 feet).
The first thing we know is that radio waves on ELF Extremely Low Frequency 3 Hz - 30 Hz can do things like world wide deep penetration of the Oceans which a VLF Very Low Frequency 3 kHz - 30 kHz system cannot do. That is why the Russian 82 Hertz Super Low Frequency SLF transmissions continue in 2009.
So what did the USA do to replace its 76 Hz land based submarine broadcast system and reestablish a nuclear attack deterrent?
TACAMO (Take Charge and Move Out) is a USA Navy system designed for use during a nuclear war. TACAMO connects the orders of the USA National Command Authority to US submarines who carry nuclear bombs fitted to their missiles.
The USA Naval Air Systems Command TACAMO program uses aircraft to transmit the Very Low Frequencies (VLF) broadcasts that where done by its two vulnerable land based SLF stations.
Aircraft use a very very long trailing wire antenna from a high altitude for their Very Low Frequency transmitting antenna. This reestablished the nuclear deterrent because these VLF aircraft are a backup to the land VLF radio stations that maintain the communications link with submarines using MFSK (Minimum Frequency Shift Keying, Minimum Frequency Shift Carrier) on VLF 3 kHz - 30 kHz.
To gain more insight into the 22 Hz antenna question we can ask what has been learned from the Russian Navy transmitter on 82 Hz and the earlier American Navy system on 76 Hz?
SLF Super Low Frequency 30 Hz - 300 Hz have Super Long Wave radio wavelengths that are 10,000 km to 1,000 km long. The energy of the transmitter is placed deep into the Earth by operating over poorly conducting earth. Poorly conducting earth allows the SLF wave to reach further down into the Earth and achieve “coupling” so that the whole Earth’s surface becomes “the antenna”. The amount of energy that is coupled to Earth is small but it will travel around the Earth making this frequency ideal for broadcasts to submarines.
The USA Navy nuclear response submarine communications system TACAMO (Take Charge and Move Out) test to transmit on ELF frequencies from aircraft were unsuccessful because the ELF energy is too far above the Earths surface to be able to “couple” to earth and so use the advantage of ELF where the entire Earth can become the “antenna.”
This then gives one idea for antenna design involving coupling energy to earth where little soil and poorly conducting rock is the ideal location.
The band below ELF is the TLF Tremendously Low Frequency 0 Hz to 3 Hz where vibrations in the Earth can be detected extending up into the ELF. This is the basis of exploration into earthquake early warning systems using these frequencies to Earth coupled antennas.
Let’s look closer at the frequencies in the ELF Extremely Low Frequency 3 Hz - 30 Hz which contains the frequency 22 Hz.
There was a TV movie that showed a man who made a receiver that heard plants crying when they were cut or upset.
Antennas in the TLF and ELF bands from 0 Hz to 40 Hz can detect electric fields as noise which can be varied by passing clouds, the movement of tree leaves, people, animals and birds.
If the purpose of the antenna is other than detecting such electric fields then it should be mounted away from those objects and raised above the ground by a few metres.
Antennas in the TLF an ELF bands from 0 Hz to 40 Hz should be well made to avoid vibration or movement.
If necessary it is also possible to construct an amplifier between the 22 Hz ELF antenna and the ELF receiver.
A sharp low pass filter can be used to remove 60 Hz (60 Hertz in the USA) or 50 Hz (50 Hz in Australia and Europe) background noise originating from power lines and radio noise emission from computers to allow reception below those frequencies.
Lunchtime in Galkayo, Somalia 17 October 2007.
Free TLF, ELF, SLF, ULF and VLF radio receiver.
Free TLF radio receiver 0 Hz – 3 Hz.
Free ELF radio receiver 3 Hz – 30 Hz.
Free SLF radio receiver 30 Hz – 300 Hz.
Free ULF radio receiver 300 Hz – 3 kHz.
Free VLF radio receiver 3 kHz – 22 kHz.
This free VLF radio receiver is free software that will make your computer into a 0 to 22 kHz radio receiver.
This software is made by Swedish radio amateur Johan SM6LKM.
This is the VLF radio receiver used by Sam Voron VK2BVS in Sydney, Australia.
Video: Receiving VLF with PC and software only.
PC sound card with 192 KHz sample rate allows reception from 0 to 96 KHz.
PC sound card with 96 KHz sample rate allows reception from 0 to 48 KHz.
PC sound card with 44 KHz sample rate allows reception from 0 to 22 KHz.
https://www.youtube.com/watch?v=UrJ77GiBNQw
Download this free VLF radio receiver: SAQrx VLF Receiver.
Download free software here to turn your computer into a VLF SAQ radio receiver.
https://sites.google.com/site/sm6lkm/saqrx-vlf-receiver
Video: SAQ Grimeton UN-DAY 2021 Transmission on October 24th 17:00 CET (15.00 UTC).
Morse code in 2021.
https://www.youtube.com/watch?v=f6cEm9A71g8
The antenna used by Sam VK2BVS from 0 to 22 kHz is the simple half wave dipole horizontal wire antenna for the 1.8 MHz (160 metre amateur radio band). This antenna is designed for Medium Frequencies yet the results from 0 to 22 kHz have been very pleasing.
TLF, ELF, SLF, ULF and VLF antennas.
Here are answers to the 22 Hertz antenna question.
Home made antennas.
Using a computer as a VLF radio receiver below 22 kHz.
Radio shack floor or balcony directional VLF coil antenna.
http://www.vlf.it/harald/strangerec.htm
Loop antenna used near 0 kHz.
http://www.vlf.it/octoloop/rlt-n4ywk.htm
Induction coil antenna for 0 Hz to 100 Hz.
http://www.vlf.it/matteobruna/ULF_Induction-Coil.htm
Dipole mono pole 0 Hz to 100 Hz receiving antenna.
Low noise preamplifier for 0 Hz to 100 Hz.
http://www.vlf.it/immagine/minimal_E.html
Active Differential Antenna (Balanced active dipole antenna) for 5 Hz to 500 kHz. http://www.vlf.it/cr/differential_ant.htm
1 metre Loop antenna for 1 Hz to 100 Hz reception.
http://www.vlf.it/minimal/minimal.htm
Marconi L Long Wire antenna for 1 Hz to 24 kHz reception.
Marconi L Long Wire antenna connected to ground for 1 Hz to 100 Hz reception.
Marconi L Long Wire antenna for 4 Hz to 30 MHz.
Active amplifier from 3 Hz to 300 Hz between the wire antenna and receiver.
http://www.vlf.it/re_2/schumannsearch.html
Earth dipole antenna from 0 Hz to 2 kHz.
Earth dipole antenna from 1 Hz to 22 kHz.
http://www.vlf.it/ed/earthprobes.html
Magnetic loop antenna for 2 Hz to 50 Hz.
Magnetic loop antenna for 1 kHz to 8 kHz.
Magnetic loop antenna for 2 Hz to 25 kHz.
http://www.vlf.it/inductor/inductor.htm
VLF Bike wheel loop antenna 5 kHz to 20 kHz.
http://www.vlf.it/bikeloop/bykeloop.htm
RDF Radio Direction Finding Loop antenna on VLF 3 kHz to 20 kHz.
http://www.vlf.it/rdfsoftware/rdf.html
ELF VLF Loop antenna design.
http://www.vlf.it/looptheo7/looptheo7.htm
Loop antenna for 200 Hz to 20 KHz.
http://www.vlf.it/easyloop/_easyloop.htm
ELF low noise amplifier from 1 Hz to 22 kHz.
http://www.vlf.it/preOP27/op027a.htm
24 hour Radio monitoring (listening) from TLF to VLF.
http://www.vlf.it/unattended/unattended.html
The Listening below 22 kHz website.
Listen to the online 0 – 24 kHz VLF receivers showing both man made and natural VLF radio emissions.
Listen to the online VLF radio receivers in Africa.
Hermanus Magnetic Observatory (studying Ultra Low Frequency waves), Hermanus, South Africa.
University of KwaZulu-Natal, Durban, South Africa.
Listen to the online VLF radio receivers in Antarctica.
Antarctica New Zealand, Scott Base, Ross Island, Antarctica.
Australian Antarctic Division, Davis base, Vestfold Hills, Princess Elizabeth Land, Antarctica.
British Antarctic Survey BAS, Rothera research station, Rothera Point, Adelaide Island, Antarctic Peninsula.
South African National Antarctic Expedition, SANAE Base, Nunatak, Vesleskarvet, Antarctica.
Listen to the online VLF receivers in Asia.
Chinese Academy of Sciences, Beijing, China.
Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Insitute, Lanzhou, China.
Chinese Academy of Sciences, Nanjing, China.
National University of Singapore.
Osaka University, Osaka, Japan.
Listen to the online VLF receiver in the Atlantic Ocean.
Ascension Island Magnetic Observatory, British Geological Survey, Ascension Island.
Listen to the online VLF receivers in Australia.
Australian Antarctic Division, Kingston, Tasmania, Australia.
Davis base (see Antarctica).
Charles Darwin University, Darwin, N.T., Australia.
Griffith University, Brisbane, QLD, Australia.
Murdoch University, Perth, W.A., Australia.
Listen to the online VLF receivers in Europe.
Eotvos Lorand University, Budapest, Hungary.
Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (ISMIRAN), Moscow, Russia.
Instituto de Meteorologia, Lisbon, Portugal, Portugal Meteorological Institute (Instituto de Meteorologia), Lisbon, Portugal.
Sodankya Geophysical Observatory, University of Oulu, Sodankyla, Finland.
University of Sheffield, Sheffield, England.
Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia. (Aeronomy is the investigation of the upper atmosphere).
Listen to the online VLF receiver in the Middle East.
Tel Aviv University, Tel Aviv, Israel.
Listen to the online VLF receivers in the Pacific Ocean.
University of French Polynesia, (Université de la Polynésie Française UPF), Lightning studies, Papeete, Tahiti.
University of Hawaii, Manoa, Honolulu, USA Pacific Ocean.
University of the South Pacific, Suva, Fiji.
Listen to the on line VLF receivers in South America.
Brazilian National Institute for Space Research (Instituto Nacional de Pesquisas Espaciais INPE), Sao Paulo, Brazil.
Centre for Geophysical Research (Centro de Investigaciones Geofisicas CIGEFI), University of Costa Rica, San Jose, Costa Rica.
Instituto Geofisico del Peru, Huancayo, Peru. See Jicamarca Radio Observatory JRO http://en.wikipedia.org/wiki/Jicamarca_Radio_Observatory
National Autonomous University of Mexico (Universidad Nacional Autonoma de Mexico UNAM), Merxico City, Mexico.
National University of Cordoba (Universidad Nacional de Cordoba UNC), Cordoba, Argentina.
University of Puerto Rico (Universidad de Puerto Rico UPR), Mayaguez, Puerto Rico.
See the online VLF receivers in the USA.
Florida State University FSU, Department of Meteorology, Tallahassee, Florida, USA.
Hawaii (see Pacific Ocean).
Los Alamos National Laboratory, Los Alamos, USA.
Massachusetts Institute of Technology, Boston, USA.
United States Geological Survey USGS, Magnetic Observatories, Boulder, Colorado, USA.
University of California, Los Angeles (UCLA) Deptment of Atmospheric and Oceanic Sciences, Los Angeles, USA.
University of Washington, Seattle, USA.
See all the above 0 Hz to 24 kHz VLF receivers
http://webflash.ess.washington.edu/spectra.html
See the World Wide Lightning Location Network Map based on multiple 0 Hz to 24 kHz VLF radio receivers http://webflash.ess.washington.edu
30 Hz to 30 kHz Receiver online here:
https://asv.org.au/lmro_whistler
http://internetwebservers.com:8000/whistler
TLF, ELF, SLF, ULF and VLF software.
Free software to make your computer into a 0 to 22 kHz radio receiver.
This software is made by Swedish radio amateur Johan SM6LKM.
Video: Receiving VLF with PC and software only.
PC sound card with 192 KHz sample rate allows reception from 0 to 96 KHz.
PC sound card with 96 KHz sample rate allows reception from 0 to 48 KHz.
PC sound card with 44 KHz sample rate allows reception from 0 to 22 KHz.
https://www.youtube.com/watch?v=UrJ77GiBNQw
Download this free VLF radio receiver: SAQrx VLF Receiver.
Download free software here to turn your computer into a VLF SAQ radio receiver.
https://sites.google.com/site/sm6lkm/saqrx-vlf-receiver
Video: SAQ Grimeton UN-DAY 2021 Transmission on October 24th 17:00 CET (15.00 UTC).
Morse code in 2021.
https://www.youtube.com/watch?v=f6cEm9A71g8
Amateur Radio Software by German amateur radio station DL4YHF. developed since 2000 the latest version June 2009 is now available for free download.
Audio Spectrum Analyzer “Spectrum Lab”.
http://www.qsl.net/dl4yhf/spectra1.html
Using a pc with sound card as a VLF radio receiver.
https://www.qsl.net/dl4yhf/speclab/vlf_rcvr.htm
SDR Software Defined Receivers https://airspy.com
Open air shopping in Galkayo, Somalia 7 October 2007.
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