CETa UPDATED EXAM SCRIPT QUESTIONS AND ANSWERS
GRADED A+
✔✔F Layer - ✔✔Approximately 250 miles and above the earth, reflects most High
Frequency signals back to the earth.
✔✔Extremely Low Frequency - ✔✔30-300 Hertz
✔✔Super Low Frequency - ✔✔300 Hertz-3 Kilohertz
✔✔Very Low Frequency - ✔✔3 Kilohertz-30 Kilohertz
✔✔Low Frequency - ✔✔30 Kilohertz-300 Kilohertz
✔✔Medium Frequency - ✔✔300 Kilohertz-3 Megahertz
✔✔High Frequency - ✔✔3 Megahertz-30 Megahertz
✔✔Very High Frequency - ✔✔30 Megahertz-300 Megahertz
✔✔Ultra High Frequency - ✔✔300 Megahertz-3 Gigahertz
✔✔Super High Frequency - ✔✔3 Gigahertz-30 Gigahertz
✔✔Extremely High Frequency - ✔✔30 Gigahertz-300 Gigahertz
✔✔2 MHz - ✔✔Frequencies below ____ can be propagated via surface waves over
great distances.
✔✔30 MHz - ✔✔Frequencies above VHF, or ____ are often propagated as space
waves, also known as line-of-sight when used for radio communications in the VHF and
UHF bands.
✔✔HF frequencies - ✔✔_______ are ideal for sky wave propagation.
✔✔Dipole antenna - ✔✔Most basic form of Hertz antenna, can be mounted at any
height, as long as it is isolated from ground. Typical impedance is 70-75 ohms.
✔✔Folded Dipole antenna - ✔✔Has a conducting element connected across its ends.
This allows the antenna to resonate at a wider range of frequencies for greater
bandwidth. Typical impedance is 300 ohms.
✔✔Quarter-wave antenna - ✔✔Frequently used in mobile receiver-transmitter
applications, normally vertically polarized.
, ✔✔Parasitic Array - ✔✔Consist of a driven element, usually a dipole. Concentrate
signals for transmission in the desired direction. Obtain energy for transmission from
electromagnetic coupling with driven element. For reception, transfers received energy
to the driven element. Highly directional.
✔✔Microwave antenna - ✔✔Typically use a dish shaped reflector to concentrate
radiated energy into a beam.
✔✔Laminated iron and iron slugs - ✔✔These type of transformer cores have a
significant effect on the coupling within a transformer
✔✔Toroid - ✔✔These type of transformer cores concentrate the lines of force
✔✔Autotransformer - ✔✔A single coil with unique winding and selective taps
✔✔Gas Diode - ✔✔Effectively become a short when ignition threshold of gas occurs
between the plate and cathode.
✔✔Klystrons - ✔✔Oscillate by themselves for a short period when cathode is pulsed.
✔✔Magnetron - ✔✔Operate in a frequency range higher than klystrons, and are
capable of much more power. Used by RADAR and microwave ovens.
✔✔Cathode Ray Tube - ✔✔Uses an electron gun to emit electrons in the direction of a
phosphor coated surface such as a TV screen.
✔✔Shottky Diode - ✔✔A metal/metal oxide diode. Performs very well at higher
frequencies, conducts high current and has lower losses than other diode types, Found
in "switching" (DC-DC converter) power supplies.
✔✔Laser Diode - ✔✔Emits a light when turned on. That light is a very small beam, is
very coherent and may be modulated. They are an inexpensive substitute for a true
laser and are used in many printers.
✔✔Tunnel Diode - ✔✔Using special "doping" techniques, these are very unique.
Conduct at different rates and different bias levels. Used in amplification, switching,
oscillators, and other special applications.
✔✔Metal Oxide Varistor (MOV) - ✔✔Special type of diode that is designed to conduct in
either direction when a certain reverse bias level is exceeded, and is able to dissipated
an extreme amount of energy. Totally destruct when their maximum energy level is
reached, thus protecting circuits to the maximum. Are not polarity sensitive and are the
basis of the best surge suppressors.
GRADED A+
✔✔F Layer - ✔✔Approximately 250 miles and above the earth, reflects most High
Frequency signals back to the earth.
✔✔Extremely Low Frequency - ✔✔30-300 Hertz
✔✔Super Low Frequency - ✔✔300 Hertz-3 Kilohertz
✔✔Very Low Frequency - ✔✔3 Kilohertz-30 Kilohertz
✔✔Low Frequency - ✔✔30 Kilohertz-300 Kilohertz
✔✔Medium Frequency - ✔✔300 Kilohertz-3 Megahertz
✔✔High Frequency - ✔✔3 Megahertz-30 Megahertz
✔✔Very High Frequency - ✔✔30 Megahertz-300 Megahertz
✔✔Ultra High Frequency - ✔✔300 Megahertz-3 Gigahertz
✔✔Super High Frequency - ✔✔3 Gigahertz-30 Gigahertz
✔✔Extremely High Frequency - ✔✔30 Gigahertz-300 Gigahertz
✔✔2 MHz - ✔✔Frequencies below ____ can be propagated via surface waves over
great distances.
✔✔30 MHz - ✔✔Frequencies above VHF, or ____ are often propagated as space
waves, also known as line-of-sight when used for radio communications in the VHF and
UHF bands.
✔✔HF frequencies - ✔✔_______ are ideal for sky wave propagation.
✔✔Dipole antenna - ✔✔Most basic form of Hertz antenna, can be mounted at any
height, as long as it is isolated from ground. Typical impedance is 70-75 ohms.
✔✔Folded Dipole antenna - ✔✔Has a conducting element connected across its ends.
This allows the antenna to resonate at a wider range of frequencies for greater
bandwidth. Typical impedance is 300 ohms.
✔✔Quarter-wave antenna - ✔✔Frequently used in mobile receiver-transmitter
applications, normally vertically polarized.
, ✔✔Parasitic Array - ✔✔Consist of a driven element, usually a dipole. Concentrate
signals for transmission in the desired direction. Obtain energy for transmission from
electromagnetic coupling with driven element. For reception, transfers received energy
to the driven element. Highly directional.
✔✔Microwave antenna - ✔✔Typically use a dish shaped reflector to concentrate
radiated energy into a beam.
✔✔Laminated iron and iron slugs - ✔✔These type of transformer cores have a
significant effect on the coupling within a transformer
✔✔Toroid - ✔✔These type of transformer cores concentrate the lines of force
✔✔Autotransformer - ✔✔A single coil with unique winding and selective taps
✔✔Gas Diode - ✔✔Effectively become a short when ignition threshold of gas occurs
between the plate and cathode.
✔✔Klystrons - ✔✔Oscillate by themselves for a short period when cathode is pulsed.
✔✔Magnetron - ✔✔Operate in a frequency range higher than klystrons, and are
capable of much more power. Used by RADAR and microwave ovens.
✔✔Cathode Ray Tube - ✔✔Uses an electron gun to emit electrons in the direction of a
phosphor coated surface such as a TV screen.
✔✔Shottky Diode - ✔✔A metal/metal oxide diode. Performs very well at higher
frequencies, conducts high current and has lower losses than other diode types, Found
in "switching" (DC-DC converter) power supplies.
✔✔Laser Diode - ✔✔Emits a light when turned on. That light is a very small beam, is
very coherent and may be modulated. They are an inexpensive substitute for a true
laser and are used in many printers.
✔✔Tunnel Diode - ✔✔Using special "doping" techniques, these are very unique.
Conduct at different rates and different bias levels. Used in amplification, switching,
oscillators, and other special applications.
✔✔Metal Oxide Varistor (MOV) - ✔✔Special type of diode that is designed to conduct in
either direction when a certain reverse bias level is exceeded, and is able to dissipated
an extreme amount of energy. Totally destruct when their maximum energy level is
reached, thus protecting circuits to the maximum. Are not polarity sensitive and are the
basis of the best surge suppressors.
