Abstract: A collapsible `bedspring` monopole antenna is configured to be effectively non-observable in its collapsed condition and, when deployed, remains sufficiently compact to ensure very low observability characteristics, while providing broadband coverage over a wide viewing aperture. The antenna is comprised of a conductor formed as a tapered helix. One end of the conductor is coupled to an antenna feed. The outer end of the helix is looped around on itself to form a circular loop. A plurality of substantially rectilinear `radials` are soldered to distributed locations around its circular loop, so as to extend outwardly and tangentially from the outer perimeter of the loop and provide `top hat` capacitive matching elements. To define the height of the deployed antenna and to electrically short out plural locations of the helix, a plurality of conductive straps are joined to respective spaced apart locations of the helix.

Abstract: In a time division multiple access satellite communications system having a master station and one or more remote stations, frequency offset through the translation oscillator in the satellite is corrected by transmitting a pilot frequency signal, reference to a high precision oscillator, through the satellite, so as to subject the pilot frequency signal to a frequency translation and monitoring the frequency translation of the pilot frequency signal as received at the master station subsequent to its transmission through the satellite. Signals to be transmitted over the satellite communications link from the master station to remote stations are subjected to a frequency translation that is effectively complementary to the monitored frequency translation.