VHF/UHF Frequencies used by early US military satellites

The early US Department of Defense TT&C network used VHF for down-links (P-band) and UHF for up-links. The antennas used were 60 ft dishes (18 meters). The uplink frequencies were 374-376 MHz. With the 18 meter dish the gain became 30.1 dB and the beam-width 3.3o. The down-links were in the 225-260 MHz band and the antenna gain was 29.5 dB and the beam-width 5o. The 18 meter dish was installed at the following stations:

SGLS stations with 18 meter P-band dish
Designation Location Coordinates Code name
GTS Guam 13.62 N 144.87 E "GUAM"
HTS Hawaii, Kaena Point 21.56 N 158.24 W "HULA"
IOS Indian Ocean, Diego Garcia 6.34 S 72.24 E "REEF"
NHS New Hampshire, New Boston 42.95 N 71.63 W "BOSS"
Other SGLS stations
KTS Kodiak, Alaska  57.2 N 153.4 W "KODI" 
OL-5 East Africa  15.2 N 38.58 E  
VTS Vandenberg AFB  34.82 N 120.5 W "COOK"
CSOC Colorado Springs 38.84 N, 104.82 W "PIKE"
? Thule 76.87 N. 69.00  "POGO"
OTS Oakhanger 51.11 N, 0.9 W "LION"
Indian Ocean, Seychelles 4.67 S, 55.48 E "INDI"

The OL-5 station has not been identified, but here I have assumed that this is identical to Asmara, Erithrea (formerly Ethiopia) where a large U.S. ground station for eavesdropping on Soviet lunar and planetary missions was located.

Location of VHF ground stations

The use of P-band for early US military flights is well known, but very few specific frequencies for identified satellites are known. The following list is what has been possible to piece together:

Satellite (popular name) Official name Frequencies (MHz)
Midas 4   228.2 232.4
Starad   228.2 237.8
Discoverer 64 CORONA 9054 (KH-4) 228.2 237.8
Discoverer 65 CORONA 9056 (KH-4) 242.0  
LES-1   237.0  
LES-2   237.0  
LES-4   237.0  
LES-3   232.9  
LES-5   228.43 236.75
LES-6   236.755 254.14
LES-8   248.86  
LES-9   249.36  
OV-3-1   240.0  

The command system used tone-digital methods. A logical "1" was transmitted as a 95 kHz tone modulated on the uplink carrier (unknown how it was modulated on the carrier). A logical "0" was a 76 kHz tone and a logical "S" used a 65 kHz tone. These tone "bits" could be transmitted at 1 or 2 kbps rate. The amplitude envelope of the command tones were amplitude modulated at a rate of 500 or 1000 Hz with a triangular waveform in order to provide command synchronisation.

The VHF/UHF telemetry and telecommand system was replaced by the SGLS (Space-Ground Link System) operating on S-band.

Back to Space Radio Notes