The following list is a synthesis of data about stations and services operating below 22 kHz. This frequency limit is that of a SoundBlaster card operating at 44.1 kHz sampling rate, so monitoring this part of the spectrum is inexpensive and requires only a direct connection of the antenna to the S/B input – no receiver at all!
A reduced list may be found
in http://moondog.astro.louisville.edu/flares/stations.html.
The most consistent contribution is from Rick Warnett, who collected personal
listenings and data from other sources, including LWCA. Thanks to Rick
for the permission to publish his data here. Long notes and s/n reports
are from him. Signals marked with –mb- are checked By Marco Bruno, IK1ODO,
from Torino, Italy.
Signals marked with DG4BAS
are checked By Manfred Kerckhoff, DG4BAS, from Bremen, Germany.
Paul Hawkins is G4KHU.
Klaus Betke is DL4BBL.
The list is very tentative.
Any addition or correction is welcome. Data come from different sources
and cross-checking is sometimes confusing.
The frequency colours in a list represent the band, as shown below.
| VLF | Very Low Frequency | 3 kHz | 30 kHz |
| VF | Voice Frequency | 300 Hz | 3 kHz |
| ELF | Extremely low Frequency | 30 Hz | 300 Hz |
| ULF | Ultra Low Frequency | 3 Hz | 30 Hz |
21.4 kHz
NPM Lualualei in Hawaii - USN
station. Traffic heard was MSK - Lowdown 2/99- 566kW ERP
12/7/98 1334, 4T untuned loop
-95dbm noise floor @ 23K <-110dbm S/N >15db
28/8/98 2116, V40 L202 350Hz -400
-87dbm.
21.1 kHz
3SB, Datong, Peoples Republic
of China.
28/12/95 0540, HF1000 LW7 CW 200Hz
-400 -65dbm, sounds like fax!
21/4/96 2208, CW heard up to -80,
about 10 wpm.
20.9 kHz
unid – 11/9/99, msk 50 Bd (-mb-)
20.6 kHz
3SB, see also 19.5 KHz. Longwave
ID this as 3SA only 2/99.
UTR3/UQC3, no recent info, see
25.0 KHz
RAB99, RHJ77 and RHJ66, Russian
stations at Khabarovsk, Arkangelsk and Bishkek. From Longwave 2/99.
23/7/99 2131, V40 L202 CW 500Hz
needed to separate signals RTTY -86dbm.
20.5 kHz
3SA/3SB Datong Naval base, Peoples
Republic of China.
20.3 kHz
ICV, Tavolara, ITALY, 20kW ERP
(or 100kW?).
Oct./99 1015 received by DG4BAS
in msk
19.8 kHz
NSW, Harold E. Holt, Australia,
1MW ERP
Unidentified! Longwave 5/98 listed
as 100Hz 200 baud RTTY.
Longwave Feb 99 says this is North
West Cape?
NWC identified by Longwave SWL
in Japan - 8/98
23/9/95 2329, HF1000 LW7 CW 100Hz
-800Hz offset S4, fax?
28/8/98 2113, V40 L202 500Hz -60dbm.
Noise floor -91dbm. S:N 31db
27/2/99 1553, V40 VLF CW 500Hz
-500 -68dbm.
23/7/99 2134, V40 L202 CW 500Hz
-66dbm, noise -90dbm S:N 24db
19.6 kHz
GBZ, Criggons, UK, 30kW ERP. MSK,
50 Bd
Oct./99 2030 received by DG4BAS
in msk
19.4 kHz
UGE, Arkhanghelsk, Russia, 105kW
OP
19.0 kHz
GQD, Anthorn, UK, 25kW ERP
18.5 kHz
Rhauderfehn, Germany, 500kW ERP
18.2 kHz
VTX3 is an Indian Navy traffic
station. Operates from Vijananarayanam. Has been heard in USA and UK.
23/7/95 1832, HF1000 CW 200Hz
LW7 S2. CW again heard, copied by PL, confirmed callsign VTX3 and traffic
a series of numbers and alpha characters. Pauses with II characters. A
series of idents, v's traffic and II's after a break. Signal up to S2 at
times, some fading.
27/6/99 1925z, VTX3 traffic heard
from 1930, standard Morse. V40 CW 100Hz BW -550 Hz -90dbm peak.
11/7/99 2059z, VTX3 V40 CW 600Hz
peaks to -86dbm
23/7/99 2137z, VTX3 V40 l202 CW
500Hz Morse traffic -87dbm
11/7/99 1530z, VVV DE VTX3 and
tfc, then RTTY -mb-
Oct./99 1021 received by
DG4BAS in msk
18.1 kHz
UFQE, Matotchkinchar, Russia,
100kW OP rtty 50 hz shift
Oct./99 1309 received by DG4BAS
in cw
17.2 kHz
17.2 KHZ SAQ is located at Grimeton
in Sweden. The Alexanderson Alternator was built by GE of the USA and designedby
Dr Alexanderson of Sweden. The Grimeton transmitter was used to connect
Sweden with the USA and was officially opened by the King of Sweden on
July 2nd 1925 - G4KHU-.
It is run every year – see http://www.telemuseum.se/grimeton/Grimeen.HTML.
Old call was SAQ and it was originally on 16.7KHz to provide a telegraph
link to the USA and some 16 other locations throughout the Americas and
the world.
7/98 Reports of text sent in Longwave
magazine. Not heard in many US states, but much of Europe copied the signal
although noise was a problem. Now a national heritage. Operator reported
that a period of rain on the day of the transmission made "tune-up" difficult,
as it had been previously set up with dry conditions.
17.0 kHz
VTX2: Navy Vishayanarayanam, late
October 2000, CW marker (by Trond Jacobsen)
16.8 kHz
FTA, St.Assise, France, 23kW ERP
16.4 kHz
JXN, Noviken, Norway, 45kW ERP
16.3 kHz
VTX1: Navy Vishayanarayanam, 01/11/2000
08:20 UTC, CW maker (by DL4BBL)
16.0 kHz
GBR, Rugby, UK, 45Kw ERP. R.Navy,
MSK. Real center frequency is 15.980 kHz (-mb-)
15.1 kHz
Bombay, India
HWU, Rosnay, France, 400kW ERP
15.0 kHz
UIK, Vladivostok, Russia, 100kW
OP
14.881 kHz
Alpha, USSR radionavigation system.
Three stations spread across the old USSR. Not always detectable. Listed
in May '98 Longwave as 14.881KHz
26/7/96 2132, HF1000 LW8 SAM 4K
series of tones every 10s, probably LSB passband inclusion of OMEGA tones
on 13.6, 13.1, 13 and 12.9KHz. When CW 500Hz -400 .5s tone every 3.5s heard
again.
18/6/97 2100, Use Spectra-Plus
to analyse tone spacing and duration. There are three tone pulses at 3.6
second intervals with a .6 second inter-pulse spacing. Setup of HF1000
was as above and signal about -97dbm.
Oct./99 2030 regular reception
by DG4BAS
14.6 kHz
UVA, Batumi, Russia, 100kW OP
12.649 kHz
Alpha. Krasnodar, USSR 500KW.
Komosomol'sk na Amure USSR 500KW. Novosibirk, USSR 500KW.
2/99 listed in Lowdown as navaid.
Novosibirisk. 27/2/99 1547, V40 VLF CW nothing heard.
Oct./99 2030 regular reception
by DG4BAS
11.905 kHz
Alpha, Krasnodar, USSR 500KW.
Komosomol'sk na Amure, USSR 500KW. Novosibirsk, USSR 500KW.
2/99 listed in Lowdown as a Navaid.
Komosomolkamur.
27/2/99 1546, VLF V40 nothing
heard.
Oct./99 2030 regular reception
by DG4BAS
9.999 KHz
Frequencies below this limit are
NOT ALLOCATED by the International Telecommunications Union. Radiation
that affects signals with modulation products below 10KHz is subject to
ITU approval though.
8.999 kHz
No ITU comments or footnotes apply
below this frequency. No administration limits on activity.
1280 Hz
Test done at Kaford, Norway in
1979/80. ERP was 29W.
1200 Hz
MIDAC a system used by cavers
to communicate with the surface. CW is used down to 1200' below ground.
1025 Hz
Bynary tones on electric mains
power, to change accounting rates in home counters (e.g., used in Switzerland).
OOK modulation.
983 Hz
A ULF beacon available for testing
purposes in the USA. John Wright runs this from Durant Oklahoma when requested.
Ident is "R"
874 Hz
A frequency mentioned in BREAK-IN
in reference to an underground caving expedition. No details of equipment
or manufacturer was given. The VLF pages.
470 Hz
Bynary tones on electric mains
power, to change accounting rates in home counters, like 1025 Hz
SANGUINE or Project ELF. A US navy submarine communications network, originally experimental but active in '93 at latest reports. There are now two transmitter systems, both must operate to give world wide coverage. Both are long wire radiators (about 20 miles of wire 20-30 feet above ground level). Now an established system – see: http://www.fas.org/man/dod-101/navy/docs/scmp/part07.htm
Normal 76 Hz transmitters are limited to Narrow band extremely high power transmitters, with obviously low antenna efficiency. There are three stations world-wide, one was located in Maine, but this has since moved to Michigan. A second was in Puerto Rico (de-commissioned < 1997) and the third in Panama (also de-commissioned <1998). One station is operating at all times, the others on standby or maintenance. Greg (VGC) worked in the Maine transmitter for some time, "you could walk through the loading coils with another person on your back" i.e. 10 foot diameter coils. The Maine transmitter has moved and is now located at Escanaba River State Forest in Michigan's upper peninsula. A 56 mile long antenna is mounted on top of 55' poles. A second site at Clam Lake, Wisconsin is 28 miles long. GTE is the contractor. The transmitters were built by Continental Electronics. No receivers at the sites. Messages can be sent to subs at 300-400' below sea level. Data transmission rate is very low, but this is no problem as the system is only intended to send a ‘come up’ message to the sub, which will then receive the VLF transmissions. Power quoted in Longwave is 6W, but this may be erp. Alternate test frequency is 45Hz.
75 Hz
Used during US tests in the 1970's.
Replaced by 76Hz. See also 45Hz.
70 Hz
Submarine communications
60 Hz
Mains power (N. America and other
countries)
50 Hz
Mains power (Europe)
45 Hz
Navy test frequency for submarine
communications from US sites. Early 1970's tests used either 45 or 75 Hz
and were located at Clam Lake Wisconsin and Republic MI = Michigan/Minnesota.
These have since been converted to 76Hz according to Naval advice. Antennas
reported as "underground" are actually large loops, half above ground,
which look like miles of power lines with either 1, 2 or 3 conductors on
wooden poles. Tests were being opposed by the public at Clam lake. Referred
to as "Project ELF" Exotic modulation methods being attempted by HAARP
which tries to effect the circumpolar loop current in the ionosphere. Not
yet (99) effective, but can be detected at ground level.
16.6667 Hz
Mains power frequency for railways
(Norway). Also referred as ‘industrial frequency’.
13 Hz
Second Schumann resonance
10 Hz
Emissions from MIR, INSPIRE Project
7 Hz
The first Schumann resonance for
the earth ionosphere cavity. Signal level peaks at several harmonics are
also found, but higher harmonics are swamped by other random noise.
1 Hz
Frequencies in this range may
be related to earthquake & seismic events. An increase in the sub-Hertz
flux appears to precede major earthquakes & is (1991) being monitored
in California as an early warning system for possible San Andreas fault
activity. "Antennas" miles long are laid on the ground & signals are
transferred back to a central point by optical fibre for analysis.