The Design and Evaluation of Transmit and Receive Antennas for an Ionospheric Communications Probe System: B. Sloping-Vee Beams
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
Pagination or Media Count:
The purpose of this study was to design and evaluate the performance of a transmitting antenna for an HF communications probe system. Monterey, CA, was selected as the transmit site, and San Diego, CA, was selected as the receive site to establish an ionospheric communication link to test the equipment involved in the probe system. A sloping-vee antenna was chosen for initial shakedown tests to support the transmitting requirements of the probe system at 5.6, 11, and 16.8 MHz. The Eyring Ground Measurement Probe was used to measure the ground constants at the NPS beach site. The Numerical Electromagnetics Code NEC was utilized to analyze the performance of the antenna at the NPS beach, and for average, poor, fair and arctic ground conditions. The antenna provides a maximum gain of 1.46 dBi at 5.6 MHz, 5.56 dBi at 11 MHz, 8 dBi at 16.8 MHz, and positive gain at take-off angles between 3 deg and 33 deg at frequencies from 5.6 to 16.8 MHz.The VSWRs with a standard 600 Ohm to 50 Ohm impedance matching transformer 121 are 1.73 at 5.6 MHz, 1.77 at 11 MHz, and 1.53 at 16.8 MHz.
- Electrical and Electronic Equipment
- Radio Communications