Satellite Radio Frequencies

Orbital Focus - International Spaceflight Facts and Figures

Tyneside, UK
2024 Dec 14
Saturday, Day 349

Curated by:

Robert Christy

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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2202.513 SGLS 1	USA 81 1992-023A 21949	CW carrier plus side-bands	ELINT: Also transmits at 2257.530 MHz, thought to be no longer active but detected early 2011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