Vehicle-Mounted Low-Frequency Antenna.
Final rept. 15 Jan-13 Feb 68,
TRIDEA ELECTRONICS EL MONTE CA
Pagination or Media Count:
In practice, the existing 50-ft, light-weight guyed mast has proven to be unsatisfactory in semi-fixed installations, particularly those where ambient surface and air traffic causes damage to the mast, the guys and ground radials. To relieve this problem, an un-guyed fiberglass antenna structure some 32 ft in height was proposed that could be used without modification to the existing antenna tuner. A Jeep type vehicle is utilized as a firm mounting base for the self-supporting antenna structure. The vehicle also provides space and power for transporting and operating the ANTRN-24 or ANTRN-25 beacon transmitters. Efficiency of the new antenna is less than that of the 50-ft light-weight mast. This relative efficiency is not constant versus frequency but easily fulfills the operational requirements. An antenna section which fractured during wind load tests was replaced with a stronger section and the repaired antenna then demonstrated the ability to withstand high winds of both short and long duration without damage. Transmission during heavy winds is not recommended since whipping about results in severe reactive impedance changes. The wind variant detuning would, of course, cause signal drop-out. But fairly steady winds of 20 to 30 knots seemed to be acceptable for transmission conditions during the tests at Griffiss AFB. Author
- Electrical and Electronic Equipment