Location of VHF ground stations |
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:
|
|
|||
| 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" |
|
|
|||
| 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.
