Microwave− and Radio−Based Systems

Microwave System  
     A  microwave system is a system of equipment used for microwave data transmission. The typical microwave system includes radios located high atop microwave towers, which are used for the transmission of microwave communications using line of sight microwave radio technology.
     Microwaves are radio waves with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz (0.3 GHz) and 300 GHz.[1] This broad definition includes both UHF and EHF (millimeter waves), and various sources use different boundaries.[2] In all cases, microwave includes the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum, with RF engineering often putting the lower boundary at 1 GHz (30 cm), and the upper around 100 GHz (3 mm).
     A microwave system is composed of at least two microwave towers. At the top of these towers are microwave antennas. These antennas are what allow the transmitter hardware of the microwave system to transmit data from site to site. The area between the microwave system components must be clear of any major structures, such as tall buildings, mountains, or other objects that could potentially obstruct microwave transmission. Only when this has been achieved can data travel through the microwave system.
     This is why microwave communication is categorized as a “line of sight” technology. When planning a microwave radio system, one must remember the requirements of microwave equipment. Microwave antennas must be placed at the top of tall radio towers to provide a clear line communication path. This allows the microwave system data to travel the long distances required by telecommunications service providers.
     The myths run rampant with radio−based systems. Despite the rumors about the various risks and perils for the radio signal, microwave usually operates 99.99−plus percent of the time. Microwave is normally impervious to the following:
• Snow
• Sleet
• Fog
• Birds
• Pollution
• Sandstorms
• Sunspot activity

    Analog microwave communication may be most economical for use at your tower sites simply because it is already paid for and in service. If you are already operating microwave equipment, it is most likely analog. To avoid having to retrain your operators, you may want to stick with the analog microwave communication equipment you already have. Because you've already gotten comfortable with this equipment, you've probably also learned its capabilities, so you're unlikely to overburden your transport system with new digital equipment.
    Digital microwave communication utilizes more advanced, more reliable technology. It is much easier to find equipment to support this transmission method because it is the newer form of microwave communication. Because it has a higher bandwidth, it also allows you to transmit more data using more verbose protocols. The increased speeds will also decrease the time it takes to poll your microwave site equipment. This more reliable format provides for more reliable reporting with advanced communication equipment, while also allowing you to bring in your LAN connection when it becomes available at the site.

 Uses of Microwave  System
-Communocation                      -Spectroscopy
-Radar
-Radio Astronomy
-Power
-Navigation

Radio-Based System

       The first system of radio navigation was the Radio Direction Finder. By tuning in a radio station and then using a directional antenna to find the direction to the broadcasting antenna, radio sources replaced the stars and planets of celestial navigation with a system that could be used in all weather and times of day. By using triangulation, two such measurements can be plotted on a map where their intersection is the position. Commercial AM radio stations can be used for this task due to their long range and high power, but strings of low-power radio beacons were also set up specifically for this task. Early systems used a loop antenna that was rotated by hand to find the angle to the signal, while modern systems use a much more directional solenoid that is rotated rapidly by a motor, with electronics calculating the angle.

    Today's radio based systems are sophisticated, reliable and economical and provide the same technical benefits as analogue and addressable systems.

    Radio-based systems utilize a receiver with an omni-directional antenna to detect a digitally coded spread spectrum or narrow band radio transmission from an EV. In these systems, the direction of preemption is selected in the vehicle and direction-unique signal is transmitted to the intersection. Radio-based systems avoid the line-of-sight limitations associated with light- and infrared-based systems. Once a Radio frequency pulse is detected and the proper direction of travel is determined, the preemption request is processed by the phase selector and the signal controller. Today, technology has arisen to improved microwave systems. They are being used for Personal Communication Service and Cellular systems. Installations of microwaves systems are of easy nowadays than installing cables a mile long. PCS systems and cellular systems have installed microwave radio systems around the globe to further increase their range and performance. Some operators like police, fire department and emergency units use these microwave systems. The Bandwidth of microwave is costly and in need as consumers grows fast. Bandwidth may be bought but for a higher price but this would satisfy the users. Buying bandwidth would be used for the future and an increase on your capacity which means lesser traffic. Microwave systems are complex and require maintenance so it might also be a cut to the budget of buying bandwidth for users. Reliability is also a factor. Buying bandwidth is not just for capacity but also for reliability. But equipment should also be secured and reliable not just the bandwidth.
Microwave Radio System offers the following features:
   -Standard IEEE 802.3 LAN Interface
   - Standard Bell T1 1.544 Mbps Interface
   -Standard 10 Mbps or Full Duplex Ethernet
   -Lightweight package 7 Ibs (3.2kg)
   -Interference free operation
   -30C to +55C temperature range
   -EMI/RFI protection
   -Compact Size 9" antenna
   -Easy to Install
   -Easy to Maintain
 

Reference:

• http://www.ebooksx.com/search.php?key=Microwave+and+Radio+Based+Systems&type=title&page=5

• http://ntl.bts.gov/lib/jpodocs/repts_te/14097_files/section_3.htm

• http://www.smecc.org/arnold_acker.htm

• http://bigdesignevents.com/2011/09/innovations-from-world-war-ii/