Stations
The S-Meter site continuously monitors 24.8 kHz

Very Low Frequency (VLF) Stations

The S-Meter site continuously receives 24.8 kHz signals from NLK in Jim Creek, Washington, to detect real-time Sudden Ionospheric Disturbances (SID's).

T he Very Low Frequency (VLF) radio spectrum extends from 3 to 30 kHz. Standard communications receivers do not receive signals that low in frequency. Furthermore, most antennas used with standard communications receivers are optimized for higher frequencies and perform poorly in the VLF spectrum. Because of that, few Radio Amateurs or shortwave listeners have ever heard VLF signals and most know very little about the large number of stations in that part of the spectrum, what those stations are used for, or the nature of VLF radio signal propagation.

However, because VLF receivers and receiving antennas are easy to construct, the VLF spectrum attracts a small number of curious and sometimes very dedicated VLF listeners who want to learn more about this little-known and somewhat secretive part of the radio spectrum. The guide below is provided to assist them in identifying stations they receive.

Signals from powerful VLF stations can be received worldwide. They penetrate deep into the earth and deep into the sea (especially in the lower portion of the VLF spectrum) and therefore can be received by submerged submarines. Though some VLF stations have other purposes, the primary function of most VLF stations is to communicate with submerged military submarines or help them navigate underwater.

Worldwide Very Low Frequency Stations
Freq. Call Power Description
11.904761 kHz (None. but nicknamed "Alpha") (Unknown) This frequency is shared by three currently-active stations (there used to be more) that form part of the Russian Hyperbolic Radio Navigation System (Radioteknicheskaya Systema Dalyoloiy Navigatsii). One is located near the village of El'Ban, Russia. Another is at 45:24:17.9 N 38:09:29.0 E. The third is at 55:45:22.0 N 84:26:52.4 E.
12.648809 kHz (None. but nicknamed "Alpha") (Unknown) The same locations as other stations nicknamed "Alpha." See 11.904761 kHz above.
13.0 kHz (None) (Unknown) A Royal Australian Navy communication station located at Gippsland, Woodside, Victoria, Australia (on Victoria's south-eastern coast). The transmitting antenna is 1400 feet (427 meters) high and is the highest VLF antenna in the world.
14.880952 kHz (None. but nicknamed "Alpha") (Unknown) The same locations as other stations nicknamed "Alpha."See 11.904761 kHz above.
16.4 kHz JXN (Unknown) A NATO naval communication station located at Novik, Norway. It is operated by NODECA and is also used by the Norwegian Navy.
17.2 kHz SAQ (Unknown) Grimeton Radio in Varberg, Sweden. Only operates sporadically.
17.9 kHz (None, but nicknamed "Channel One") (Unknown) U.S. Navy TACAMO (Take Charge and Move Out) mobile communication stations. The transmitter locations are unknown and subject to change.
18.0 kHz (None) (Unknown) Same as 17.9 kHz above.
18.1 kHz RDL (Unknown) Multiple Russian military naval communication stations share this frequency and call sign. The transmitters are believed to be located at Krasnodar; Nizhniy Novgorod; Arkhangelsk; Tashkent, Uzbekistan; Molodechno, Belarus; and Kalinigrad.
18.1 kHz RLO (Unknown) A Russian military naval communication station. The transmitter is believed to be located at Ryazan (also spelled Riazan or R'azan), Russia.
18.1 kHz RKS (Unknown) A Russian military naval communications station. The transmitter is believed to be located at Murmansk, Russia.
18.2 kHz VTX (Unknown) An Indian Navy communication station. The transmitter is located at South Vijayanarayanam village, 18.64 miles (30 km) south of Turunelveli on the Kanyakumari highway, in India.
18.3 kHz HWU (Unknown) A French Navy communication station at Le Blanc, France.
18.9 kHz RDL & RKS (Unknown) Multiple Russian military naval communication stations share this frequency. The transmitter locations are unknown.
19.6 kHz GQD (Unknown) A British submarine communication station located near Anthorn, Combria, in the north-west region of England. The station is operated by VT Communications (part of VT Group plc.) under contract with the Royal Navy.
19.8 kHz NWC 1000 KW U.S. Navy communication station Harold E. Holt at Exmouth, Australia, that is operated by the Royal Australian Navy.
20.0 kHz VLF 6 KW transmiiter power
500 Watts ERP
A VLF beacon station located near the South Pole in Antarctica that is operated by Stanford University. The transmitting antenna is a 4.35 mile (7 km) horizontal wire dipole 4 to 5 feet above the ice. It transmits one-minute duration beacon signals at 15-minute intervals.
20.27 kHz ICV (Unknown) A NATO naval communication station located at Isola di Tavolara, Sardegna, Italy.
20.5 kHz

RJH63
RJH66
RJH69
RJH77
RJH99
RAB99

(Unknown)

Six Russian TS stations transmit on this frequency at different times. Their locations are as follows:
   RJH63 Krasnodar, Russia
   RJH66 Bishkek, Kyrgyzstan
   RJH69 Molodechno, Belarus
   RJH77 Arkhangelsk, Russia
   RJH99 Nizhniy Novgorod, Russia
   RAB99 Nizhniy Novgorod, Russia
All these stations have the nickname "Beta."

20.6 kHz 3SA (Unknown) A Chinese Navy communication station located at Changde in the Peoples Republic of China. The frequency is shared with 3SB below and transmission typically alternate between the two stations.
20.6 kHz 3SB (Unknown) A Chinese Navy communication station located at Datong in the Peoples Republic of China. The frequency is shared with 3SA above and transmission typically alternate between the two stations.
20.9 kHz HWU 500 KW A French Navy communication station located in Rosnay, France.
21.05 kHz HWU (Unknown) A French Navy communication station located in Rosnay, France.
21.1 kHz RDL (Unknown) Several Russian military naval communication stations share this frequency and call sign. One is located in Krasnodar Krai, Russia. Another is in Tashkent, Uzbekistan. The locations of the others are unknown.
21.4 kHz NPM 566 KW A U.S. Navy communication station located at Laualualei, Oahu, Hawaii.
21.75 kHz HWU (Unknown) A French Navy communication station located at Le Blanc, France.
22.2 kHz JJI (Unknown) A Japanese Navy communication station located at Ebino, Japan.
23.0 kHz RJH63
RJH66
RJH69
RJH77
RJH99
RAB99
(Unknown) Same as 20.5 kHz above
23.1 kHz (None) (Unknown) Same as 17.9 kHz above.
23.4 kHz DHO38 (Unknown) Operated for NATO by Bundesmarine, the German Navy, which likely also uses it for German submarine communications. Located at Rhauderfehn, Germany.
24.0 kHz NAA 1000 KW A U.S. Navy communication station at Cutler, Maine. This station is part of the NATO Interoperable Submarine Broadcast System.
24.8 kHz NLK 250 KW A U.S. Navy communication station located at Jim Creek, Washington. It uses a Continental Electronics Corp. transmitter and a horizontal wire transmitting antenna strung between two mountain tops.
25.0 kHz RJH63
RJH66
RJH69
RJH77
RJH99
RAB99
(Unknown) Same as 20.5 kHz above
25.0 kHz PWB (Unknown) A Brazilian Navy communication station known as Belem Radio that is located in Belem, Brazil.
25.1 kHz RJH63
RJH66
RJH69
RJH77
RJH99
RAB99
(Unknown) Same as 20.5 kHz above
25.2 kHz NML 500 KW A U.S. Navy communication station located at LaMour, North Dakota. This station is part of the NATO Interoperable Submarine Broadcast System.
25.5 kHz RJH63
RJH66
RJH69
RJH77
RJH99
RAB99
(Unknown) Same as 20.5 kHz above
25.7 kHz NOV (Unknown) Same as 17.9 kHz above.
26.6 kHz CAA2A (Unknown) A Chilean Navy communication station located at Santiago, Chile.
26.7 kHz TBB (Unknown) A Turkish Navy communication station located at Bafa, Republic of Turkey (Türkiye).
26.9 kHz NOV (Unknown) Same as 17.9 kHz above.
27.0 kHz NOV (Unknown) Same as 17.9 kHz above.
27.2 kHz NOV (Unknown) Same as 17.9 kHz above.
27.3 kHz RDL (Unknown) A Russian military headquarters communication station believed to be located in far north-eastern Russia.
27.5 kHz NOV (Unknown) Same as 17.9 kHz above.
27.6 kHz NOV (Unknown) U.S. Navy TACAMO (Take Charge and Move Out) mobile communication stations operating in or serving the Atlantic Ocean.
27.7 kHz NOV (Unknown) Same as 17.9 kHz above.
27.9 kHz NOV (Unknown) U.S. Navy TACAMO (Take Charge and Move Out) mobile communication stations operating in or serving the Pacific Ocean.
29.3 kHz NOV (Unknown) Same as 27.6 kHz above.
29.4 kHz NOV (Unknown) Same as 27.9 kHz above.
29.6 kHz NOV (Unknown) U.S. Navy TACAMO (Take Charge and Move Out) mobile communication stations worldwide.
30.00 kHz PWI (Unknown) A Brazilian Navy communication station located at Recife, Brazil.

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