Orbital Focus - International Spaceflight Facts and Figures
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Satellite Radio Frequencies


Tyneside, UK
2024 Mar 29
Friday, Day 89

Curated by:
























Elsewhere:

Details of SGLS
USAF Space-Ground Link System (SGLS)

United States government (including the security services) and military satellites generally use the fixed channels of SGLS (the Space Ground Link System). SGLS is a system in its own right and consists of a set of standards for both the uplink and downlink, and the way they interact. Ground stations are equipped with specialised SGLS equipment.

US commercial satellites and other countries' launches have their own transmission needs and use spot frequencies across the S-band spectrum that sometimes seem quite random as they try to fit in between all the other satellites in orbit.

There are twenty SGLS channels in total but some appear to be currently unused, or it may simply be that nothing has been detected recently.

Uplinks are in the L-band part of the spectrum with associated downlinks at S-band. Some satellite constellations have almost exclusive use of certain of the SGLS channels (eg - the SDS satellites in HEO and geosynchronous orbit appear to use only Channel 9).

Two NOAA satellites have been detected transmitting at the SGLS Channel 10 frequency. One, NOAA 11 is defunct and has an uncontrolled and faulty transmitter. The other, NOAA 19, is quite healthy. 2247.5 MHz is the frequency allocated to the STX4 transmitter aboard all recent NOAA satellites so patient listening may unearth the other active satellites when switched on occasionally. NOAA communicates with a civilian tracking system rather than SGLS.

NASA's AIM satellite also uses the frequency of an SGLS channel but it probably does not operate in SGLS mode.

All three of these satellites are listed here because of the frequency, not because they use SGLS.


Freq (MHz) Satellite Transmission Notes
2202.447
SGLS 1
Sicral 1A
2001-005A
26694
CW carrier plus sub-carriers at 293kHz and 297 kHz comsat: Geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2202.507
SGLS 1
USA 32
1988-078A
19460
CW carrier plus side-bands ELINT: Also transmits at 2282.5 MHz but transmissions at the two frequencies are not simultaneous
2202.513
SGLS 1
USA 81
1992-023A
21949
CW carrier plus side-bands ELINT: Also transmits at 2257.530 MHz, thought to be no longer active but detected early 2011
2207.487
SGLS 2
GFO
1998-007A
25157
CW carrier plus side-bands Oceanography - wave height measurement: Geosat Follow On - Also transmitted at 150.012 MHz and 400.032 MHz. Ceased to transmit 2008 November.
2207.500
SGLS 2
AMS 2
1977-044A
10033
CW carrier plus side-bands metsat: Advanced Meteorological Satellite - Also transmits at 2237.5MHz and 2252.5 MHz - Frequency Information contributed by the late Ivan Artner
2207.510
SGLS 2
USA 172
2003-048A
28054
CW carrier plus side-bands metsat: Defense Meteorological Satellite Program - Also transmits at 2222.5 MHz, 2237.5 MHz and 2247.5 MHz
2207.535
SGLS 2
USA 147
1999-067A
25991
CW carrier plus side-bands metsat: Defense Meteorological Satellite Program - Also transmits at 2252.5 MHz, 150.012 MHz and 400.032 MHz (the last two are the RADCAL frequencies)
2212.504
SGLS 3
Coriolis
2003-001A
27640
CW carrier plus side-bands Military science satellite: Also transmits at 2222.528 MHz
2217.500
SGLS 4
STS

CW carrier plus side bands carrying data ISS Crew/payload transport: Integrated voice and data on SGLS Channel 4 - transmitter operates almost continuously while the payload bay doors are open, also transmitted at 259.7 MHz, 1981-2011
2217.500
SGLS 4
Cloudsat
2006-016A
29107
CW carrier + sidebands NASA - cloud & precipitation studies: Frequency is approximate
2222.476
SGLS 5
USA 152
2000-047A
26473
CW carrier plus side-bands Military radar reconnaissance satellite: -
2222.481
SGLS 5
USA 172
2003-048A
28054
CW carrier plus side-bands metsat: Defense Meteorological Satellite Program - Also transmits at 2207.5, MHz, 2237.5 MHz and 2247.5 MHz
2222.487
SGLS 5
USA 210
2009-057A
35951
CW carrier plus side-bands metsat: Defense Meteorological Satellite Program
2222.497
SGLS 5
USA 191
2006-050A
29522
CW carrier plus side-bands metsat: Defense Meteorological Satellite Program - Also transmits at 2237.515 MHz and (according to observations by the late Ivan Artner) at 2249.415 MHz
2222.500
SGLS 5
USA 173
p/l 1
2003-054A
28095
CW carrier plus side-bands Ocean SIGINT: Navy Ocean Surveillance System - Also transmits at 2232.5 MHz. Frequency Information contributed by the late Ivan Artner
2222.500
SGLS 5
USA 181
p/l 1
2005-004A
28537
CW carrier plus side-bands Navy Ocean Surveillance System SIGINT: Navy Ocean Surveillance System - also transmits at 2232.5 MHz and 2277.5 MHz - latter frequency Information contributed by the late Ivan Artner
2222.502
SGLS 5
USA 133
1997-064A
25017
CW carrier plus side-bands Radar imaging reconnaissance: Frequency Information contributed by the late Ivan Artner
2222.508
SGLS 5
USA 69
1991-017A
21147
CW carrier plus side-bands Radar imaging reconnaissance: Frequency Information originally contributed by the late Ivan Artner - later confirmed by other observers
2222.528
SGLS 5
Coriolis
2003-001A
27640
CW carrier plus side-bands Military science satellite: Frequency Information contributed by the late Ivan Artner, also transmits at 2212.504 MHz
2227.476
SGLS 6
NATO 4B
1993-076A
22921
CW carrier plus side-bands comsat GEO: Geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2227.481
SGLS 6
NATO 4A
1991-001A
21047
PSK with sub-carrier, 1024 kHz comsat GEO: Geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2227.487
SGLS 6
Skynet 4C
1990-079A
20776
CW carrier plus side-bands comsat: Geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2227.497
SGLS 6
Skynet 4E
1999-009B
25639
CW carrier plus side-bands comsat: Geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2227.508
SGLS 6
Skynet 4D
1998-002A
25134
CW carrier plus side-bands comsat: Geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2227.514
SGLS 6
Skynet 4F
2001-005B
26695
CW carrier plus side-bands comsat: Geosynchronous orbit -
2232.495
SGLS 7
USA 118
1996-026A
23855
CW carrier plus side-bands Multi-tasking military satellite at 13° west longitude?: Geosynchonous orbit - Frequency Information contributed by the late Ivan Artner
2232.495
SGLS 7
USA 160
p/l 1
2001-040A
26905
CW carrier plus side-bands Ocean SIGINT: Also reported to transmit 2277.5 MHz
2232.496
SGLS 7
USA 105
1994-054A
23223
CW carrier plus side-bands Multi-tasking military satellite at 27°.5 west longitude: Geosynchonous orbit - Frequency Information contributed by the late Ivan Artner
2232.497
SGLS 7
USA 159
2001-033A
26880
FM wide-bandwidth data early warning: Defense Support Program also transmits at 2237.5 MHz - Frequency Information contributed by the late Ivan Artner
2232.498
SGLS 7
USA 149
2000-024A
26356
FM wide-bandwidth data early warning: Defense Support Program also transmits at 2237.5 MHz - Frequency Information contributed by the late Ivan Artner
2232.498
SGLS 7
USA 173
p/l 1
2003-054A
28095
CW carrier plus side-bands Ocean SIGINT: Transmission may be from 28097 (NOSS 3-2 follower). Also reported to transmit at 2222.5 MHz
2232.498
SGLS 7
USA 194
p/l 1
2007-027A
31701
CW carrier + side bands Navy Ocean Surveillance System - ocean SIGINT: Transmission may be from the NOSS 3-4 follower
2232.500
SGLS 7
USA 181
p/l 1
2005-004A
28537
CW carrier plus side-bands Navy Ocean Surveillance System SIGINT: Also reported to transmit at 2222.5 MHz and 2277.5 MHz - latter frequency Information contributed by the late Ivan Artner
2232.504
SGLS 7
USA 197
2007-054A
32287
CW carrier plus side-bands early warning: Defense Support Program - Frequency Information contributed by Greg Roberts
2232.511
SGLS 7
USA 75
1991-080B
21805
FM wide-bandwidth data early warning: Defense Support Program also transmits at 2237.5 MHz - Frequency Information contributed by the late Ivan Artner
2232.517
SGLS 7
USA 184
2006-027A
29249
CW carrier plus side-bands : Also transmits at 2277.5 MHz - Frequency Information contributed by the late Ivan Artner
2237.480
SGLS 8
USA 149
2000-024A
26356
PSK with sub-carrier, 1024 kHz early warning: Defense Support Program - Also transmits at 2232.5 MHz - Frequency Information contributed by the late Ivan Artner
2237.495
SGLS 8
USA 142
1999-017A
25669
CW carrier plus side-bands early warning: Defense Support Program, suffered mission failure, satellite stranded in geosynchronous transfer orbit - Frequency Information contributed by the late Ivan Artner
2237.496
SGLS 8
USA 75
1991-080B
21805
CW carrier plus side-bands early warning: Defense Support Program - Also transmits at 2232.5 MHz - Frequency Information contributed by the late Ivan Artner
2237.499
SGLS 8
USA 159
2001-033A
26880
PSK with sub-carrier, 1024 kHz early warning: Also transmits at 2232.5 MHz - Frequency Information contributed by the late Ivan Artner
2237.500
SGLS 8
AMS 2
1977-044A
10033
CW - wide sweeping carrier metsat: Advanced Meteorological Satellite - Also transmits at 2207.5MHz and 2252.5 MHz
2237.500
SGLS 8
USA 131
1997-012A
24753
CW + side-bands metsat: Defense Meteorological Satellite Program
2237.512
SGLS 8
USA 172
2003-048A
28054
CW + side-bands metsat: Defense Meteorological Satellite Program - Also transmits at 2207.5 MHz, 2222.473 MHz and 2247.415 MHz
2237.514
SGLS 8
USA 191
2006-050A
29522
CW metsat: Defense Meteorological Satellite Program - Also transmits at 2222.5 MHz and 2247.415 MHz
2237.515
SGLS 8
USA 109
1995-015A
23533
CW + side-bands metsat: Defense Meteorological Satellite Program
2237.517
SGLS 8
USA 147
1999-067A
25991
CW - wide sweeping carrier metsat: Defense Meteorological Satellite Program - Also transmits at 2207.535 MHz, 2252.5 MHz, 150.012 MHz and 400.032 MHz (the last two are the RADCAL frequencies)
2237.517
SGLS 8
USA 210
2009-057A
35951
CW carrier plus sidebands metsat: Strong carrier
2237.518
SGLS 8
OPS 3151
1977-007A
9803
CW carrier plus side-bands early warning: Defunct satellite in geosynchronous 'graveyard' orbit - Frequency Information contributed by the late Ivan Artner
2242.485
SGLS 9
USA 116
1995-066A
23728
CW carrier + sidebands imaging gov/mil: Identified from a single radio observation (early 2008) which is not normally sufficient. However, there is significant circumstantial evidence that the identification is correct.

No longer in orbit
2242.485
SGLS 9
USA 129
1996-072A
24680
CW carrier plus side-bands imaging gov/mil: Possible small error in the frequency measurement
2242.485
SGLS 9
USA 161
2001-044A
26934
CW carrier + sidebands imaging gov/mil: -
2242.486
SGLS 9
USA 155
2000-080A
26635
PSK with sub-carrier, 1024 kHz comsat GEO: Geosynchronous orbit, frequency variable according to onboard power available - increases significantly at times of eclipse. Also transmitted at 251.325 MHz, 252.675, 258.775 and 268.775 MHz. No longer operational.
2242.493
SGLS 9
USA 8
1985-010B
15543
CW carrier plus side-bands SIGINT: Frequency information from Greg Roberts
2242.495
SGLS 9
USA 137
1998-005A
25148
CW carrier plus side-bands comsat: Part of a constellation of three satellites in highly eccentric orbit (HEO), switches to low power when over the southern hemisphere - formerly transmitted AFSATCOM signal near 243.7 MHz. Reported still active 2013 May. Lost to visual observers because of changes brought about gravity effects and air drag on the eccentric orbit.
2242.496
SGLS 9
USA 67
1990-097B
20963
PSK with sub-carrier, 1024 kHz comsat GEO: Originally equatorial GEO but the orbit has evolved to an inclination of 15° and is slightly elliptical so reception varies according to the sub-satellite latitude - a study by Ivan Artner 2006 March showed that the transmitter responds to eclipse periods by becoming intermittent while out of direct sunlight, indicating that the batteries are not charging properly from the solar cells
2242.498
SGLS 9
USA 125
1996-038A
23945
CW carrier plus side-bands comsat: Formerly part of the operational constellation of three SDS satellites in highly eccentric orbit (HEO) - Also transmitted AFSATCOM signal near 243.7 MHz. The S-band transmission from USA-125, an SDS-2 satellite, was at a lower power than the SDS-3 satellites. Ceased to transmit around 2010 Aug 31 when either the transmitter was switched off, or the satellite was guided to a destructive re-entry.
2242.500
SGLS 9
USA 40
1989-061B
20167
CW carrier, oscillates in frequency due to satellite spinning at 5.2s per rev comsat: Tentative identification of satellite with received signals - non-operational but still transmitting, the signal oscillation is probably due to the originally de-spun aerial platform having matched rotation with the satellite body - identified as 90020 in classfd.tle
2242.500
SGLS 9
USA 89
1992-086B
22518
CW carrier plus side-bands comsat: During 2006, Ivan Artner tracked a spinning satellite in HEO, the times did not fit known satellites in that type of orbit - it has been tentatively identified as 90026 (last observed in 2004) but transmissions ceased during the first quarter of 2007 before an orbit could be determined, the identification of it as USA-89 is also tentative
2242.500
SGLS 9
USA 162
2001-046A
26948
CW carrier (plus side-bands?) comsat: Reported frequency for satellite in geosynchronous orbit - also reported to transmit at 250.075 MHz, 256.475, 263.225 and 267.550 MHz
2242.503
SGLS 9
USA 179
2004-034A
28384
CW carrier plus side-bands - strong comsat: Part of a constellation of three satellites in highly eccentric orbit (HEO), switches to low power when over the southern hemisphere - Also transmits at 251.700 MHz and 256.375 MHz
2242.504
SGLS 9
USA 198
2007-060A
32378
CW carrier plus side-bands - strong comsat: Part of a constellation of three satellites in highly eccentric orbit (HEO), lanched 2007 Dec 10 as a replacement for USA-125, also transmits at 251.700 MHz and 256.375 MHz, and used 251.275 and 258.800 MHz during the orbital test phase up to 2008 Mar 13

Frequency discovered independently by Bob Christy and Sven Grahn about 20 minutes after launch.
2242.504
SGLS 9
USA 227
2011-011A
37377
Carrier + sidebands comsat GEO: Continous transmission
2242.505
SGLS 9
USA 186
2005-042A
28888
CW carrier + sidebands imaging gov/mil: -
2242.506
SGLS 9
USA 215
2010-046A
37162
CW Reconnaissance using radar: Discovered by Bob Christy immediately after launch
2242.506
SGLS 9
USA 234
2012-014A
38109
Carrier + sidebands Reconnaissance using radar:
2242.514
SGLS 9
USA 224
2011-002A
37348
CW carrier + sidebands imaging gov/mil: Discovered by Bob Christy on day of launch. Intensive radio tracking over first few days allowed good determination of the orbit for acquisition by visual observers.
2242.515
SGLS 9
OPS 7940
1976-080A
9270
CW carrier, oscillates in frequency due to satellite spinning at 4.6s per rev comsat: Highly eccentric orbit, non-operational, signal oscillation is probably due to the originally de-spun aerial platform having matched rotation with the satellite body, SDS 2 - listed in classfd.tle as 90004
2242.517
SGLS 9
ASTEX
1971-089A
5560
Multiple sidebands - very small dispersion Technology experiments: Old satellite detected as still transmitting during 2008 March
2247.478
SGLS 10
TSX-5
2000-030A
26374
CW carrier Experiments in advanced space technologies: Frequency is unstable, noted as high as 2247.512 MHz, came back on air 2009 November
2247.499
SGLS 10
USA 208
2009-052A
35937
CW carrier plus sidebands STSS Demonstrator dual satellite mission together with USA 209 testing missile detection technology: Frequency shows variability, possibly due to internal electrical power loading. Transmission frequency sometimes locked to the uplink leading to dual Doppler effect.

See 2272.5 MHz for USA-209.
2247.500
SGLS 10
NOAA 11
1988-089A
19531
Cyclic carrier - approx 4s on then 4s off metsat: Satellite de-commissioned and batteries disconnected 2004 Jun 22 at 16:24:28 UTC - output from STX4 transmitter detected 2009 Oct, probably powered by output from solar cells (only detectable on daylight passes)
2247.500
SGLS 10
NOAA 19
2009-005A
33591
Data metsat: STX4 transmitter - used during launch and contingency, occasionally heard from orbit and heard to switch on and off, detected 2009 Oct
2252.490
SGLS 11
USA 95
1993-056A
22787
CW carrier plus side-bands comsat GEO: Frequency Information contributed by the late Ivan Artner
2252.490
SGLS 11
USA 146
1999-063A
25967
PSK with sub-carrier, 1.7 MHz comsat: Frequency Information contributed by the late Ivan Artner - co-located so this may be UFO-F11
2252.493
SGLS 11
USA 127
1996-042A
23967
PSK with sub-carrier, 1.7 MHz comsat: Frequency Information contributed by the late Ivan Artner
2252.499
SGLS 11
USA 147
1999-067A
25991
CW carrier plus side-bands metsat: Defense Meteorological Satellite Program - Also transmits at 2207.535 MHz, 2237.5 MHz, 150.012 MHz and 400.032 MHz (the last two are the RADCAL frequencies)
2252.500
SGLS 11
AMS 2
1977-044A
10033
CW carrier plus side-bands metsat: Advanced Meteorological Satellite - Also transmits at 2207.5 MHz and 2234.5 MHz - Frequency Information contributed by the late Ivan Artner
2252.500
SGLS 11
USA 109
1995-015A
23533
CW carrier plus side-bands metsat: Defense Meteorological Satellite Program, - Frequency Information contributed by the late Ivan Artner
2252.506
SGLS 11
USA 207
2009-047A
35815
CW carrier + sidebands comsat GEO: Initial reception reported by Greg Roberts (SA) some 38 minutes after lift-off
2257.500
SGLS 12
DSCS III
F-1
1982-106B
13637
CW carrier plus side-bands comsat GEO: Possibly defunct, in geosynchronous drift orbit - Frequency Information contributed by the late Ivan Artner
2257.508
SGLS 12
USA 153
2000-065A
26575
PSK with sub-carrier, 1024 kHz comsat GEO: Defense Satellite Communications System, geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2257.511
SGLS 12
USA 167
2003-008A
27691
CW carrier plus side-bands comsat GEO: Defense Satellite Communications System, geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2257.512
SGLS 12
USA 97
1993-074A
22915
CW carrier plus side-bands comsat GEO: Defense Satellite Communications System, geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2257.530
SGLS 12
USA 81
1992-023A
21949
CW carrier plus side-bands ELINT: Also transmits at 2202.5 MHz and 258.150 MHz, , frequency may be active intermittently
2262.493
SGLS 13
USA 46
1989-077A
20253
PSK with sub-carrier, 1024 kHz comsat: Frequency Information contributed by the late Ivan Artner
2262.499
SGLS 13
USA 174
2003-057A
28117
PSK with sub-carrier, 1.7 MHz comsat: Frequency Information contributed by the late Ivan Artner - co-located so this may be UFO-F10
2262.505
SGLS 13
USA 214
2010-039A
36868
CW carrier, for a period after launch, the received frequency was oscillating because of Doppler shift caused by rotation comsat GEO: Unable to reach GEO using designated thrusters so manoeuvred to GEO over a long period using its station-keeping thrusters
2262.507
SGLS 13
USA 164
2002-001A
27168
CW carrier plus side-bands comsat: Also transmits 2267.513 MHz, geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2262.509
SGLS 13
USA 99
1994-009A
22988
CW carrier plus side-bands comsat: Geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2267.513
SGLS 14
USA 164
2002-001A
27168
CW carrier plus side-bands comsat: Occasional transmission - Also transmits 2262.507 MHz MHz, geosynchronous orbit - Frequency Information contributed by the late Ivan Artner
2272.514
SGLS 15
USA 209
2009-052B
35938
CW carrier plus sidebands STSS Demonstrator dual satellite mission together with USA 208 testing missile detection technology: Frequency shows variability, possibly due to internal electrical power loading. Transmission frequency sometimes locked to the uplink leading to dual Doppler effect.

See 2247.5 MHz for USA-208.
2232.498
SGLS 16
USA 198
2007-060A
32378
CW carrier plus side-bands comsat: Navy Ocean Surveillance System
2277.485
SGLS 16
OPS 4029
1981-107A
12930
CW carrier plus side-bands Multi-tasking military satellite at 41° west longitude?: Geosynchronous orbit Frequency Information contributed by the late Ivan Artner
2277.500
SGLS 16
USA 78
1992-006A
21873
CW carrier plus side-bands comsat GEO: Defunct satellite in geostationary drift orbit - Frequency Information contributed by the late Ivan Artner
2277.500
SGLS 16
USA 105
1994-054A
23223
CW carrier plus side-bands Multi-tasking military satellite at 27°.5 west longitude: Frequency Information contributed by the late Ivan Artner
2277.500
SGLS 16
USA 160
p/l 1
2001-040A
26905
CW carrier plus side-bands Ocean SIGINT: Navy Ocean Surveillance System - Frequency Information contributed by the late Ivan Artner, also transmits at 2232.5 MHz
2277.500
SGLS 16
USA 181
p/l 1
2005-004A
28537
CW carrier plus side-bands Navy Ocean Surveillance System SIGINT: Navy Ocean Surveillance System, also transmits at 2222.5 MHz and 2232.5 MHz
2277.520
SGLS 16
USA 184
2006-027A
29249
CW carrier plus side-bands : Also transmits at 2232.5 MHz - Frequency Information contributed by the late Ivan Artner
2282.500
SGLS 17
MSX
1996-024A
23851
AM - 1 kHz tone Missile detection experiments: Midcourse Space Experiment, infrared sources with a view to improved design of missile detecting sensors - Frequency Information contributed by the late Ivan Artner
2282.500
SGLS 17
AIM
2007-015A
31304
FM science: Indistinct lines when viewed with SDR and software
2282.507
SGLS 17
USA 32
1988-078A
19460
CW carrier plus side-bands ELINT: Observed to switch on and off and does not transmit every rev - at least while over Europe, also transmits 2202.5 MHz but transmissions at the two frequencies are not simultaneous
2287.500
SGLS 18
Aqua
2002-022A
27424
CW carrier + sidebands Climate research: Frequency is +/-10 kHz
2287.500
SGLS 18
Aura
2004-026A
28376
CW carrier + sidebands Climate research: Frequency is +/-10 kHz
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