Harris Corporation

At&t Bell Laboratories

American Telephone and Telegraph, Co.

M Phillip Arnold

George W Waters

Thomas J Kabana

Albert J Massanova

John P Hall

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. When allowed to expand toward its deployed configuration, the bedspring imparts a tensile force to the straps, which are pulled taught, thereby limiting the expansion of the bedspring. That portion of the helix between the closest point of strap attachment and its feed point effectively inserts an inductance in the antenna circuit path between the feed point and what is effectively an `open mesh cone-shaped monopole`.

Collapsible, low visibility, broadband tapered helix monopole antenna

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. At a remote station, received signals are monitored for a difference in the corrected frequency (base upon the use of the precision oscillator at the master site) relative to a prescribed frequency and signals to be transmitted from the remote station to the master station are adjusted by an amount that effectively compensates for the difference between the prescribed frequency and the monitored frequency.

Frequency translation correction scheme for satellite communication

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Melbourne, FL, United States of America

M Phillip Arnold