UHF-Satcom.com - C-Band monitoring    (Work In Progress)                                                                   Updated: (28/05/2011 13:40:47 +0100)

C-band is usually associated with 'old style' satellite TV downlinks, but there are many interesting transmissions to be heard, including Inmarsat communications, old SCPC telephone circuits, many different flavours of satellite modems and of course some TV transmissions. Some of the C-band stuff mentioned on this page comes from the HEO Molniya series of satellites.

The minimum sized dish is about a 1.2m, with a good C-band LNA and down converter. If you can find a crystal controlled converter, the phase noise of the oscillator will be low allowing for narrow band CW signals to be resolved.

The picture on the left shows a typical C-band PLL down converter. There is a good quality oscillator that runs at 1716.6666MHz and is referenced from an internal OCXO. The 1.7GHz signal is amplified, and filtered leaving only the 5150MHz which is used as the local oscillator.

The NF of the converter is pretty high at around 15dB, but this is fronted by a good quality LNA, i.e. something with a <1dB NF. The converter needs about +18v to keep in lock.

Pictures below show a typical setup with modified C-band LNB to tap out the 4GHz signal ready to feed to the down converter. Use a cheap LNB from eBay that has a low noise figure, remove the IF and DRO and tap the 4GHz signal out.

Geostationary Satellites - 3.6GHz to 4.2GHz sky survey - Nils, pjm

Satellite	RF Freq		IF Freq		Modulation
Position	MHz		MHz		characteristics
===========================================================================
40.5e		3703.7875	1446.2125	Very strong PSK
Express AM1	3947.500	1202.500	TT&C
		3950.000	1250.000	Continuous carrier
				
33e		3703.115	1446.885	Possible TT&C
Intelsat 802	3738.100	1411.900	FM channel with data
RHCP		3738.145	1411.855	FM channel with data
		4099.750	1050.250	Strong PSK
		
26e		4178.005	971.995		Continuous carrier
Badr-C

25.5e		3599.650	1550.350	PSK
Inmarsat 3F5	3603.550	1546.450	PSK
		3603.750	1546.250	PSK
		3603.800	1546.200	PSK
		3604.275	1545.725	PSK
		3604.375	1545.625	PSK
		3605.250	1544.750	PSK
		3605.450	1544.550	PSK
		3607.525	1542.475	Continuous carrier
		3608.425	1541.575	20 PSK channels
		3610.250	1539.750	PSK
		3610.375	1539.625	PSK
		3610.750	1539.250	PSK

1w		3812.000R	1338.000	Frequency hopping modem
Intelsat 10-02	3872.000R	1278.000	Continuous carrier
		3947.500R	1202.500	TT&C
		3952.500R	1197.500	TT&C
		3938.100R	1211.900	Narrow PSK
		4027.575R	1122.425	Narrow PSK
 		4009.565L	1140.435	Analogue phone channel
 		4009.655L	1140.345	Analogue phone channel paired with 4010.962
 		4009.700L	1140.300	Analogue phone channel paired with 4010.369
		4009.745L	1140.255	Analogue phone channel
		4009.790L	1140.210	Analogue phone channel
		4009.832L	1140.168	Analogue phone channel
		4010.015L	1139.985	Analogue phone channel
		4010.150L	1139.850	Analogue phone channel
		4010.195L	1139.805	Analogue phone channel
		4010.330L	1139.670	Analogue phone channel
		4010.369L	1139.631	Analogue phone channel paired with 4009.700
		4010.375L	1139.625	Analogue phone channel
		4010.690L	1139.310	Analogue phone channel
		4010.827L	1139.173	Analogue phone channel
		4010.874L	1139.126	Analogue phone channel
		4010.962L	1139.038	Analogue phone channel paired with 4009.655
		4011.189L	1138.811	Analogue phone channel
		4011.233L	1138.767	Analogue phone channel
		4011.278L	1138.722	Analogue phone channel
		4011.369L	1138.631	Analogue phone channel
		4011.413L	1138.587	Analogue phone channel
		4011.459L	1138.541	Analogue phone channel
		4011.503L	1138.497	Analogue phone channel
		4011.594L	1138.406	Analogue phone channel
		4011.638L	1138.362	Analogue phone channel
		4011.685L	1138.315	Analogue phone channel
		4011.907L	1138.093	Analogue phone channel
		4012.269L	1137.731	Analogue phone channel
		4012.360L	1137.640	Analogue phone channel
		4012.447L	1137.553	Analogue phone channel
		4012.629L	1137.371	Analogue phone channel
		4012.717L	1137.283	Analogue phone channel
		4012.896L	1137.104	Analogue phone channel
		4012.985L	1137.015	Analogue phone channel
		4013.124L	1136.876	Analogue phone channel
		4013.210L	1136.790	Analogue phone channel
		4013.303L	1136.697	Analogue phone channel
		4013.437L	1136.563	Analogue phone channel
		4013.480L	1136.520	Analogue phone channel
		4013.572L	1136.428	Analogue phone channel
		4013.617L	1136.383	Analogue phone channel
		4013.750L	1136.250	Analogue phone channel
		4013.799L	1136.201	Analogue phone channel
		4013.842L	1136.158	Analogue phone channel
		4013.884L	1136.116	Analogue phone channel
		4013.935L	1136.065	Analogue phone channel
		4014.000L	1136.000	Analogue phone channel


(above) SCPC traffic at C-band on 1w LHCP.

5w		3759.245R	1390.755	Narrow band PSK data
Atlantic Bird	4016.140R	1133.860	Continuous carrier
		4027.710R	1122.290	PSK
		4028.060R	1121.940	Strong PSK
		4199.500L	950.500		TT&C

8w		3818.500	1331.500	Possible TT&C
Telecom 2D	3892.510	1257.490	Possible TT&C
		3905.075	1244.925	PSK
		3905.250	1244.750	PSK
		3941.750	1208.250	PSK
			
11w		3700.000	1450.000	Continuous carrier
Express A3	3775.000	1375.000	Continuous carrier
		3800.000	1350.000	Continuous carrier
		3941.750	1208.250	Very strong PSK
			
14w		3758.270	1391.730	Narrow band PSK
Express 4A	3758.330	1391.670	Slow rate FSK data
		3759.250	1390.750	TT&C / Data
		3800.010	1349.990	Continuous carrier
		3950.675	1199.325	Data with two sidebands
			
15.5w		3605.425	1544.575	Analogue phone channel (1535.425 return)
Inmarsat 3F2	3605.450	1544.550	Analogue phone channel (1535.450 return)
		3605.475	1544.525	Analogue phone channel (1535.475 return)
		3605.500	1544.500	Analogue phone channel (1535.500 return)
		3605.525	1544.475	Analogue phone channel (1535.525 return)
		3608.450	1541.550	Analogue phone channel (1538.450 return)
		3608.475	1541.525	Analogue phone channel (1538.475 return)
		3609.875	1540.125	Analogue phone channel (1539.875 return)
		3610.050	1539.950	Analogue phone channel (1540.050 return)
		3610.975	1539.025	Analogue phone channel (1540.975 return)
		3611.025	1538.975	Analogue phone channel (1541.025 return)
		3611.200	1538.800	Analogue phone channel (1541.200 return)
		3612.000	1538.000	Analogue phone channel (1542.000 return)
			
		Transponder		RX band MHz             TX band MHz
		Forward			6424.000 to 6454.000    1525.000 to 1559.000
		Return			1626.500 to 1660.500    3600.000 to 3629.000
		C to C			6432.300 to 6433.200    3607.300 to 3608.200
		L to L			1640.850 to 1641.850    1539.350 to 1540.350
		Nav (Egnos etc)		3629.400 to 3631.600
					1574.400 to 1576.600

18w		3947.500	1202.500	TT&C
Intelsat 901	3950.000	1200.000	continuous carrier
RHCP		3952.500	1197.500	TT&C
		4065.075	1084.925	Radio Station Feeder (not 24h)
LHCP		4194.175	955.825		Strong PSK

22w		3873.000	1277.000	Strong PSK
NSS 7		3943.275	1206.725	Strong PSK

24.5w		3952.500	1197.500	TT&C
Intelsat 905	3961.800	1188.200	Very strong PSK

27.5w		3894.275	1255.725	Very Strong PSK
Intelsat 907	3947.500	1202.500	TT&C
RHCP		3952.500	1197.500	TT&C
		3959.110	1190.890	Analogue phone circuit
		3959.155	1190.845	Analogue phone circuit
		3959.785	1190.215	Arabic Radio Station feeder
		3959.875	1190.125	Analogue phone circuit
		3959.920	1190.080	Analogue phone circuit
		3959.650	1190.350	Analogue phone circuit
		3960.370	1189.630	Analogue phone circuit
		3960.595	1189.405	Analogue phone circuit
		3960.865	1189.135	Analogue phone circuit
		3960.945	1189.055	Analogue phone circuit
		3961.085	1188.915	Analogue phone circuit
		3961.270	1188.730	Analogue phone circuit
		3961.360	1188.640	Analogue phone circuit
		3961.405	1188.595	Analogue phone circuit
		3961.585	1188.415	Analogue phone circuit
		3961.810	1188.190	Very strong PSK
		3961.945	1188.055	Analogue phone circuit
		3962.080	1187.920	Analogue phone circuit with periodic ASCII data
		3962.620	1187.380	Analogue phone circuit
		3962.710	1187.290	Analogue phone circuit
		3962.940	1187.060	Analogue phone circuit
		3963.295	1186.705	Analogue phone circuit
		3963.465	1186.535	Analogue phone circuit
		3963.520	1186.480	Analogue phone circuit
		3964.005	1185.995	Analogue phone circuit
		3986.700	1163.300	Radio Station Feeder
			
31.5w		3650.475	1499.525	Very strong PSK
Intelsat 801	3650.550	1499.450	Very strong PSK
RHCP		3650.775	1499.225	PSK
		3651.425	1498.575	PSK
		3651.575	1498.425	PSK
		3651.600	1498.400	PSK
		3723.875	1426.125	Cluster of 12 narrow band PSK
		3789.000	1361.000	Continuous carrier
		3789.305	1360.695	Analogue phone circuit
		3789.425	1360.575	Analogue phone circuit
		3789.545	1360.455	Analogue phone circuit
		3789.6625	1360.3375	Analogue phone circuit
		3790.025	1359.975	Analogue phone circuit
		3790.980	1359.020	Analogue phone circuit
		3795.120	1354.880	Analogue phone circuit
		3795.180	1354.8125	Analogue phone circuit
		3795.420	1354.575	Analogue phone circuit
		3795.540	1354.460	Analogue phone circuit
		3795.6625	1354.3375	Analogue phone circuit
		3796.800	1353.200	Analogue phone circuit
		3796.980	1353.020	Analogue phone circuit
		3798.000	1352.000	Continuous carrier
		3807.120	1342.880	Analogue phone circuit
		3807.182	1342.818	Analogue phone circuit
		3807.205	1342.795	Analogue phone circuit
		3807.360	1342.640	Analogue phone circuit
		3807.450	1342.550	Analogue phone circuit
		3807.750	1342.250	Analogue phone circuit
		3807.870	1342.130	Analogue phone circuit
		3807.902	1342.098	Analogue phone circuit
		3807.925	1342.075	Analogue phone circuit
		3808.084	1341.916	Analogue phone circuit
		3808.175	1341.825	Analogue phone circuit
		3808.320	1341.680	Analogue phone circuit
		3808.439	1341.561	Analogue phone circuit
		3815.790	1334.210	African Radio Feeder with stereo pilots
		3947.500	1202.500	TT&C
		3950.000	1200.000	Tracking Beacon
		3952.500	1197.500	TT&C
LHCP		3899.967	1250.033	Continuous carrier
		4117.100	1032.900	PSK
		
34.0w		3945.526	1204.474	TT&C 1000bps DBPSK
Marisat F2	
Highly inclined
	

(above) Marisat-F2 TT&C at 3945.526

34.5w   RHCP	3932.825	1217.175	PSK
Intelsat 903	3947.500	1202.500	TT&C
		3952.500	1197.500	TT&C
		3669.275	1480.725	PSK
		4104.925	1045.075	PSK
LHCP		3695.500	1454.500 QRT?	Radio Station Feeder - Danish Radio Faro/Greenland (Tnx Brian-DK)
		3698.000	1452.000 QRT?	Radio Station Feeder (Norway)
		3701.2525	1448.7475	Carrier with flutter
		3703.000	1447.000 QRT?	Radio Station Feeder - Danish Radio Programme 1 (Tnx Brian-DK)
		

(above) Spectrum of Danmarks Radio feeder via 34.5 west at 3703.000 LHCP

37.5w Hor	4008.020	1141.980	French station Tropical music (Tnx to LR)

40.5w   RHCP	3628.730	1521.270	Very strong PSK
NSS 806		3629.360	1520.640	Very strong PSK
		3725.000	1425.000	Continuous carrier
		3861.500	1288.500	Continuous carrier
		3947.500	1202.500	TT&C
		3952.500	1197.500	TT&C
			
43w		3703.000	1447.000	Possible TT&C Carrier + 2 sidebands
Panamsat 3R	3719.400	1430.600	Strong PSK
		3991.900	1158.100	PSK
		4199.500	950.500		Possible TT&C Carrier + 2 sidebands

45w		3801.450	1348.550	Continuous Carrier
Panamsat 1R	4126.300	1023.700	Very strong PSK
		4198.490	951.510		Possible TT&C Carrier + 2 sidebands
		4198.990	951.010		Possible TT&C Carrier + 2 sidebands
		4199.510	950.490		Continuous Carrier
		
50w	RHCP	3952.000	1198.000	TT&C
Intelsat 705	3950.000	1200.000	Continuous carrier
		3947.500	1202.500	TT&C
		
109.2W	Hor	3897.915	1252.085	Unknown FM station from San Diego Cal.
Satmex 6	3897.120	1252.880 	Unknown FM station
(Tnx to LR)	3891.330	1258.670	Unknown Jazz station
Ver		3899.730	1250.270	La voz de Guayana. Estado Bolivar ( Bolivar State) 89.7 FM Spanish

Some general information about Intelsat TT&C tracking beacons:

Intelsat Satellite Designation	Frequency (MHz)		IF (MHz)
VII, VIIA, VIII, VIIIA and IX	3,947.500 		1202.500
				3,948.000 		1202.000
Note: only two of these may	3,952.000 		1198.000
be active at any one time	3,952.500		1197.500

				3,950.000 		1200.000 continuous carrier
				
Panamsat satellites use the following c-band frequencies for tt&c / beacons
				Frequency (MHz)		IF (MHz)
				4198.500		951.500
				4199.000		951.000
				4199.500		950.500

More to come!

Tnx to c.h. for this great info!

High Earth Orbit Satellites - 3.6GHz to 4.2GHz sky survey - pjm

Satellite	RF Freq		IF Freq		Modulation
MHz MHz characteristics
=========================================================================== Meridian 3 3691.000 1459.000 2MHz wide lump 3645.000 1505.000 500MHz wide lump 3625.000 1525.000 PSK with sidebands, strong 3610.025 1539.975 50 bps FSK 3605.000 1545.000 400KHz wide noise 'lump' possible TPX loop Molniya 3-53 3857.555 1292.445 PSK HEO 3758.900 1391.100 Very strong PSK (periodic Doppler correction on downlink) USSR Apogee 3765.640 1384.360 DSSS 3770.445 1379.555 DSSS 3870.425 1279.575 DSSS 3882.925 1267.075 DSSS 3657.610 1492.390 PSK Canada Apogee 3680.765 1469.235 PSK (New 8/7/2006) 3758.875 1391.125 PSK 3760.950 1389.050 PSK 3761.650 1388.350 PSK 3764.650 1385.350 PSK (New 8/7/2006) 3857.520 1292.490 PSK 3869.720 1280.280 PSK Molniya 3-5? 3759.030 1390.970 PSK HEO 3760.855 1389.145 PSK Canada Apogee 3761.550 1388.450 PSK 3764.600 1385.400 PSK with regular framing Transponder frequencies for Molniya-1 C-Band (obtained from observations) TPX-1 3700.000 to 3750.000 50MHz b/w TPX-2 3775.000 to 3825.000 50MHz b/w TPX-3 3850.000 to 3900.000 50MHz b/w Transponder frequencies for Molniya-3 C-Band (obtained from observations) TPX-1 3650.000 to 3700.000 50MHz b/w TPX-2 3750.000 to 3800.000 50MHz b/w TPX-3 3850.000 to 3900.000 50MHz b/w

3758.900 from Molniya 3-53 HEO

3760.770 from Molniya 3-53 HEO