Considerations in the Design of Two Mc Loran Transmitters Intended to Reduce Side Bands and Permit Cycle-Machine Operation
Abstract
Loran transmitters currently in service are of pulsed oscillator type. They suffer from pulse and frequency instability. Their signals occupy large bands in the spectrum with consequent inter-channel interference in addition to interfering with the operation of other service. Greater accuracy in Loran systems may be obtained by matching individual r-f cycles, the first prerequisite of which is rigid control of the radio frequency and phase of the transmitter output. Since present Loran transmitters are not compatible with the requirements for reduction of side-band radiation and cycle-matching techniques, and investigation was conducted to ascertain the possibilities in the design of new Loran transmitters. A simple method of deriving the radio frequency from the Loran Timer's crystal oscillator has been evolved, thus permitting the use of cycle-matching techniques and insuring excellent frequency stability. Sidebands may be minimized by controlling the shape of the pulse. This report describes the techniques employed and the results obtained with an experimental grid-modulated crystal-oscillator power-amplifier transmitter.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 13, 1946
- Accession Number
- AD1196235
Entities
People
- Merle V. Hoover
Organizations
- United States Naval Research Laboratory