Reconnaissance and Surveillance Leader Course Antenna Theory

Reconnaissance and Surveillance Leader Course TERMINAL LERNING OBJECTIVE Action:Identify the principles of Antenna Theory Condition: Denied the use of references Standard:Answer test questions correctly that pertain to Radio Wave Propagation

Reconnaissance and Surveillance Leader Course Waves

Reconnaissance and Surveillance Leader Course Wave Motion

Reconnaissance and Surveillance Leader Course Radio Wave Speed oRADIO WAVES TRAVEL AT THE SPEED OF LIGHT oTHE SPEED OF LIGHT IS MILES PER SECOND

Reconnaissance and Surveillance Leader Course Antenna Theory LAMBDA GREEK SYMBOL FOR WAVELENGTH

Reconnaissance and Surveillance Leader Course WAVELENGTH 1 FULL WAVELENGTH Antenna Theory

Reconnaissance and Surveillance Leader Course ANTENNA DESIGNS THERE ARE TWO BASIC ANTENNA DESIGNS: 1. RESONANT 2. NON-RESONANT Antenna Theory

Reconnaissance and Surveillance Leader Course Antenna Formulas OFull Wavelength (Divide 936 By The Frequency) OHalf Wavelength (Divide 468 By The Frequency) OQuarter Wavelength (Divide 234 By The Frequency)

Reconnaissance and Surveillance Leader Course RESONANT ANTENNA FORMULA WORK SHEET FREQUENCYLENGTH FULL___ HALF___ QUART___ Antenna Theory

Reconnaissance and Surveillance Leader Course Answers Freq¼½FULL ft84.32 ft ft ft52.29 ft ft ft ft ft ft45.09 ft90.17 ft

Reconnaissance and Surveillance Leader Course Polarization THE RELATIONSHIP OF THE RADIO ENERGY RADIATED BY AN ANTENNA TO THE SURFACE OF THE EARTH

Reconnaissance and Surveillance Leader Course Horizontal Polarization

Reconnaissance and Surveillance Leader Course Vertical Polarization

Reconnaissance and Surveillance Leader Course Radiation Patterns oOMNI-DIRECTIONAL oBI DIRECTIONAL oUNI-DIRECTIONAL

Reconnaissance and Surveillance Leader Course Gain Gain is simply how efficiently your antenna radiates the power sent to it: To increase the gain of your antenna, simple double its length, notionally, every 3dB of gain doubles the efficiency of the antenna.

Reconnaissance and Surveillance Leader Course Take Off Angle THE ANGLE ABOVE THE HORIZON THAT AN ANTENNA RADIATES THE LARGEST AMOUNT OF ENERGY

Reconnaissance and Surveillance Leader Course Take Off Angle

Reconnaissance and Surveillance Leader Course Example Radiation Pattern Take Off Angle

Reconnaissance and Surveillance Leader Course Take Off Angle 3/4 λ ABOVE GROUND 1/2 λ ABOVE GROUND 1/4 λ ABOVE GROUND 1 1/2 λ ABOVE GROUND

Reconnaissance and Surveillance Leader Course Critical Angle EARTH 5 MHz WAVE NOT REFRACTED TAKE-OFF ANGLE 5 MHz WAVE IONOSPHERE REFRACTED WAVE

Reconnaissance and Surveillance Leader Course Ionosphere Take-Off Angle of Incidence Angle Of Incidence

Reconnaissance and Surveillance Leader Course Critical Angle

Reconnaissance and Surveillance Leader Course Effects of Radiation Angle on Distance

Reconnaissance and Surveillance Leader Course Near Vertical Incidence Sky-wave (NVIS) OVery High Take Off Angle OShort Range HF Communications O Mile Footprint OOmni-directional OAchieved By Keeping Antennas Low To The Ground (Dipole: 1/8 To 1/4 Above Ground)

Reconnaissance and Surveillance Leader Course Near Vertical Incidence Sky-wave (NVIS)

Reconnaissance and Surveillance Leader Course Near Vertical Incidence Sky-wave (NVIS)

Reconnaissance and Surveillance Leader Course Fading OA Variation In Signal Strength Of A Received Radio Signal OCaused By Random Changes Of Polarization During Sky-wave Transmissions

Reconnaissance and Surveillance Leader Course Relative Conductivity SURFACE RELATIVE CONDUCTIVITY SEA WATER GOOD FLAT, LOAMY SOIL FAIR FRESH WATER GOOD ROCK TERRAIN POOR DESERT POOR JUNGLE POOR

Reconnaissance and Surveillance Leader Course Counterpoise OUsed When Ground Conductivity Is Poor OErected A Short Distance Off The Ground OEqual To Or Longer Than The Antenna

Reconnaissance and Surveillance Leader Course Counterpoise 3-5 ft Separation λ/4 or less

Reconnaissance and Surveillance Leader Course Counterpoise

Reconnaissance and Surveillance Leader Course Q: How fast do radio waves travel? A: 186,000 Miles/Second Q: What is the Greek symbol for a wavelength? Review Q: What is the formula for figuring what the 1/4 wavelength for an antenna is? A: 234 /Frequency(MHZ) LAMBDA A:

Reconnaissance and Surveillance Leader Course Q: What are the two types of polarization? A: Vertical & Horizontal Q: What are the three types of radiation patterns? A: Omni-directional, Uni-directional & Bi-directional Review

Reconnaissance and Surveillance Leader Course -Has a very high take off angle -Designed for short range HF communications miles -Omni-Directional -Achieved by keeping antennas low to the ground (Dipole: 1/8 to 1/4 above the ground) -Ideally will eliminate the skip zone Review Q: What is the NVIS effect?

Reconnaissance and Surveillance Leader Course Antenna Theory