Satellite long distance service. unaffected by HF Radio propagation problems, fading, high
attenuation of cable. Voice Frequency Channels VFCT. Phase I IDSCS voice channels on IDSCS satellite up link
and down link. Two RF channels, RF bandwidth. Reflection and refraction only slightly affected by atmospheric phennomena.
Unreliable HF propagation for tactical communications. Satellite earth terminals. highly directional antennas
invulnerable to jamming. Wide bandwidth system use anti-jamming modulation, spread spectrum and frequency hopping.
anti jam, frequency hop, spread spectrum radio.
