Accession Number : ADA327261

Title :   Technique for Building and Calibrating VLF/LF Receive Loop Antennas.

Descriptive Note : Final rept.,

Corporate Author : NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA

Personal Author(s) : Birkett, J M

PDF Url : ADA327261

Report Date : Apr 1997

Pagination or Media Count : 31

Abstract : The strategic VLF/LF submarine communications program involves several VLF and LF transmitter antennas located around the world. The Naval Command, Control and Ocean Surveillance Center (NCCOSC), Research, Development, Test and Evaluation Division (NRAD) is often tasked to baseline the antenna's performance before and after changes are made. One parameter useful in this process is measurement of the VLF/LF transmit antenna's magnetic field strength. The antenna's magnetic field strength provides information on the antenna's effective height, radiated power, and efficiency. Prior to making these measurements, the VLF/LF receive loop must first be calibrated in a Helmholtz coil. Determining magnetic field strength can then be accomplished by taking readings with the VLF/LF receive loop antenna while in the field of the transmit antenna. The voltage induced around the receive loop is measured by a selective level meter (Hewlett Packard 3486C0). Distance from the transmitting antenna to the VLF/LF receive loop is provided using Global Positioning System (GPS) instruments. Antenna current is measured in the helix house of the transmit antenna with a time stamp data recorder. Many of the transmit antenna's performance characteristics can be derived with the above measurements. The purpose of this document is to detail the construction method for building the VLF/LF receive loop antenna as designed by Mr. Don Watt of Watt Engineering. The second portion of this report describes the Helmholtz loop calibration procedure.

Descriptors :   *LOOP ANTENNAS, *STRATEGIC COMMUNICATIONS, *SUBMARINE ANTENNAS, ANTENNAS, CALIBRATION, CONSTRUCTION, FIELD INTENSITY, GLOBAL POSITIONING SYSTEM, LOOPS, LOW FREQUENCY, MAGNETIC FIELDS, MEASUREMENT, MEASURING INSTRUMENTS, MISSIONS, NAVY, OCEAN SURVEILLANCE, PARAMETERS, POWER, RADIATION, RECORDING SYSTEMS, TRANSMITTERS, TRANSMITTING, VERY LOW FREQUENCY

Subject Categories : Electrical and Electronic Equipment
      Submarine Engineering
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE