Defense Communications Agency Cost and Planning Factors Manual. Change 2.
Abstract
Line-of-sight (LOS) microwave systems normally use the frequency spectrum from 2 to 12 gigahertz (GHz). The LOS path lengths range from 1 to 100 miles depending upon propagation, terrain, frequency, and tower height, among other engineering considerations. The average system consists of path lengths of approximately 30 miles. The total microwave system consists of terminals, relays, and thenormal support functions required for any communications system, such as technical control, multiplex, utilities, land, and buildings. LOS microwave transmission is usually dual diversity, using either frequency, space, or polarization diversity. The transmission system will generally contain dual receive and transmit equipment at all locations for use as either frequency diversity systems or hot standby systems for redundancy. Two techniques may be employed for the transmission and multiplexing of communications circuits. DCS uses frequency modulation transmission and frequency division multiplex (FDM) also called analog systems. Currently DCS uses digital transmission and time division multiplex (TDM), referred to as digital systems.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 23, 1985
- Accession Number
- ADA163319
Entities
Organizations
- Defense Information Systems Agency