Communications, Radar & Electronic Warfare (201.. - Index of

Introduction 19For the communications and electronic warfare operator, most of the hardwareparameters are fixed based on the equipment they and the enemy have. In fact, inmany cases the only factors under the operator' s control will be usually parameterssuch as:• Radio output power, which may be selected from pre-set values or may be availablein a range between minimum and maximum values.• Transmission frequency, either from pre-selected values or a range. This will affectpropagation loss.• Radio mode, which may affect certain performance parameters. For example, asystem that can transmit voice, encrypted voice, video, etc. will have differentcharacteristics.• Selection from a range of feeder cables and connectors.• Selection of sub-systems such as matching tuners or external amplifiers.• Selection of antenna type.• Positioning of the antenna main beam in terms of location, height above localground, direction and tilt.Some of these selections will be determined by the type of signal being sent andothers will depend on a variety of factors such as adherence to spectrum managementrules, installation design rules, limitations due to available equipment and environmentalfactors. These environmental factors are considered next.1.3.2 Useful Conversion Fo rmulaeMany units are used in radio engineering, and it is often necessary to conve11 from onetype of unit to another. This section lists a number of useful formulae.1.3.2.1 Power ConversionsThese formulae are used to convert between power in W, dBW and dBm.Power(dBW) =1000g[Poli'er(W)](poll'er(dBW))10Power(W) = 10Power(dBm) = Pmver(dBW)-301.3.2.2 Receiver Sensitivity ConversionsThese formulae are used to convert between sensitivity units of dBm, IlV and dBIlV