Description : The minimum number of turns a helix antenna must have. A. 4 B. 5 C. 3 D. 6
Last Answer : C. 3
Description : What is the gain, in dB of a helical antenna with diameter of λ/3, 10 turns at pitch of λ/4, used at 100 MHz? A. 16 B. 41.1 C. 31.4 D. 1.25
Last Answer : A. 16
Description : At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna? A. Minimum voltage and minimum current B. Equal voltage and current C. Minimum voltage and maximum current D. Maximum voltage and minimum current.
Last Answer : D. Maximum voltage and minimum current.
Description : Where do the maximum current and minimum voltage values on a resonant Hertz dipole exist? A. Center of the antenna B. Near the end of the antenna C. Near the center of the antenna D. Ends of the antenna
Last Answer : A. Center of the antenna
Description : An ungrounded antenna near the ground A. acts as a single antenna of twice the height B. is unlikely to need an earth mat C. acts as antenna array D. must be horizontally polarized
Last Answer : C. acts as antenna array
Description : When a capacitor is connected in series with a Marconi antenna? A. Antenna open circuit stops transmission B. An inductor of equal value must be added C. No change occurs to antenna D. Antenna resonant frequency increases
Last Answer : D. Antenna resonant frequency increases
Description : A disadvantage of using a trap antenna. A. It will radiate harmonics B. It can only be used for single-bad operation C. It is too sharply directional at lower frequencies D. It must be neutralized
Last Answer : A. It will radiate harmonics
Description : A one-quarter wavelength shunt-fed vertical Marconi antenna A. has maximum radiation in a vertical direction B. must have a horizontal receiving antenna for the best reception C. must use a receiving antenna for the best reception D. must have a vertical receiving antenna for the best reception
Last Answer : D. must have a vertical receiving antenna for the best reception
Description : In testing transmitter to prevent interfering with other stations, which type of antenna must be used? A. Void antenna B. Dummy antenna C. Hertzian antenna D. Isotropic antenna
Last Answer : B. Dummy antenna
Description : If the current ratios of the two or more elements must be held 5% and the phase angle to 3° the antenna is called a A. end fire array B. critical phased array C. broadband array D. wideband array
Last Answer : B. critical phased array
Description : When testing transmitter to prevent interfering with other stations, which type of antenna must be used? A. Dummy antenna B. Hertzian antenna C. None of these D. Void antenna
Last Answer : A. Dummy antenna
Description : The input signal of a travelling wave tube is introduced at A. Cathode B. Anode C. Cathode end of the helix D. Collector end of the helix
Last Answer : C. Cathode end of the helix
Description : What is the effective radiated power of a repeater with 120 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna gain? A. 601 W B. 240 W C. 60 W D. 379 W
Last Answer : C. 60 W
Description : What is the effective radiated power of a repeater with 75 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna gain? A. 37.6 W B. 237 W C. 150 W D. 23.7 W
Last Answer : A. 37.6 W
Description : What is the gain of an antenna over a half-wavelength dipole when it has 6 dB gain over an isotropic radiator? A. 6.0 dB B. 8.1 dB C. 3.9 dB D. 10.0 dB
Last Answer : C. 3.9 dB
Description : A Hertz antenna is operating on a frequency of 2182 kHz and consists of a horizontal wire that is hanged between two towers. What is the frequency of its third harmonic? A. 727 kHz B. 6546 kHz C. 436 kHz D. 6.546 kHz
Last Answer : B. 6546 kHz
Description : If the radiated power increase 10.89 times, the antenna current increases by ______. A. 3.3 times B. 6.6 times C. 1.82 times D. 10.89 times
Last Answer : A. 3.3 times
Description : A dipole antenna requires to be fed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11kW ... Gain referred to this particular dipole). A. 4.75 B. 2.6 C. 1.81 D. 4.24
Last Answer : B. 2.6
Description : If the antenna increases 3.3 times how much does the radiated power increase? A. 3.3 times B. 10.89 times C. 9.9 times D. 6.6 times
Last Answer : B. 10.89 times
Description : A receiver connected to an antenna whose resistance is 50 Ω has an equivalent noise resistance of 30Ω. Calculate its equivalent noise temperature if the noise figure is equal to 1.6. A. 17.4 K B. 174K C. 1.74K D. 17K
Last Answer : B. 174K
Description : What is the effective radiated power of a repeater with 50 watts transmitter power output \, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 6 dB antenna gain? A. 158 W B. 39.7 W C. 251 W D. 69.9 W
Last Answer : B. 39.7 W
Description : How does the gain of a parabolic dish type antenna change when the operating frequency is doubled? A. Gain does not change B. Gain is multiplied by 0.707 C. Gain increases 6 dB D. Gain increases 3 dB
Last Answer : C. Gain increases 6 dB
Description : If a transmission line has a power loss of 6 dB per 100 feet, what is the power at the feed point to the antenna at the end of a 200 foot transmission line fed by a 100 watt transmitter? A. 70 watts B. 50 watts C. 25 watts D. 6 watts
Last Answer : D. 6 watts
Description : Determine the dB gain of a receiving antenna which delivers a microvolt signal to a transmission line over that of an antenna that delivers a 20 microvolt signal under identical circumstances. A. 10 dB B. 6 dB C. 3 dB D. 8 dB
Last Answer : B. 6 dB
Description : How much does the radiated power of an antenna increases if its current increased by 3.3 times? A. 6.6 times B. 3.3 times C. 10.89 times D. 9.9 times
Last Answer : C. 10.89 times
Description : A dipole antenna requires to be feed with 20 kW of power to produce a given signal strength to a particular distant point. If the addition of a reflector makes the same field strength available with an input power of 11 ... ( Gain referred to this particular dipole) A. 4.24 B. 1.81 C. 4.75 D. 2.6
Last Answer : D. 2.6
Description : What is the gain of four identically polarized antennas stacked one above the other and fed in phase? A. 3 dB over the gain of one antenna B. 10 dB over the gain of one antenna C. 4 dB over the gain of one antenna D. 6 dB over the gain of one antenna
Last Answer : D. 6 dB over the gain of one antenna
Description : _____ is an antenna made up of a number of full wavelengths A. Elementary doublet B. Log-periodic C. Long wire D. Whip
Last Answer : C. Long wire
Description : What is antenna bandwidth? A. Antenna length divided by the number of elements B. The angle between the half-power radiation points C. The angle formed between two imaginary lines drawn through D. The frequency range over which an antenna can be expected to operate satisfactorily
Last Answer : D. The frequency range over which an antenna can be expected to operate satisfactorily
Description : _____ is an antenna with a number of half-wave antenna on it. A. Antenna array B. Tower C. Omni-directional D. Rhombic
Last Answer : A. Antenna array
Description : What is meant by the term antenna bandwidth A. Antenna length divided by the number of elements. B. The angle between the half-power radiation points C. The frequency range over which and antenna ... perform well D. The angle formed between two imaginary line drawn through the ends of the elements
Last Answer : C. The frequency range over which and antenna can be expected to perform well
Description : It consists of a number of dipoles of equal size, equally spaced along a straight line with all dipoles fed in the same phase from the same source. A. Log-periodic antenna B. Yagi antenna C. End-fire array D. Broadside array
Last Answer : D. Broadside array
Description : If the length of an antenna is changed from 2.5 meters to 2.8 meters, its resonant frequency will A. increase B. depend on the velocity factor so the resonant frequency can either be increased or decreased C. will be unchanged D. decrease
Last Answer : D. decrease
Description : In a typical mobile satellite array antenna if three elements are activated, how many elements are deactivated? A. 3 B. 11 C. 5 D. 9
Last Answer : B. 11
Description : What is the effective radiated power of a repeater with 100 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? A. 800 W B. 126 W C. 12.5 W D. 1260 W
Last Answer : B. 126 W
Description : What is the effective radiated power of a repeater with 50 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 7 dB antenna gain? A. 300 W B. 315 W C. 31.5 W D. 69.9 W
Last Answer : C. 31.5 W
Description : A transmitted signal 5 meters in wavelength is received by an antenna coil having a 50-Ω resistance and a 0.01 H inductance. What is the capacitance of the tuner shunting the antenna coil at this point? A. 0.704 fF B. 0.704 μF C. 0.704 nF D. 0.704 mF
Last Answer : A. 0.704 fF
Description : A transmitter supplies 8 kW to the antenna when it is unmodulated, determine the total radiated power when modulated at 90%. A. 5 kW B. 20 kW C. 15 kW D. 8.36 kW
Last Answer : D. 8.36 kW
Description : The frequency of operation of a dipole antenna cut to length of 3.4 m. A. 42.9 MHz B. 61.3 MHz C. 38.5 MHz D. 53.5 MHz
Last Answer : A. 42.9 MHz
Description : What quarterwave transformer will match a 100Ω line to an antenna whose value is 175Ω? A. 132.29 Ω B. 150 Ω C. 16.58 Ω D. 137.5 Ω
Last Answer : A. 132.29 Ω
Description : To radiate power efficiently, a long-wire antenna must have what minimum overall length?
Last Answer : One-half wavelength.
Description : Which antenna does not use the ground? A. Marconi B. Yagi C. Hertz D. Rhombic
Last Answer : B. Yagi
Description : Which antenna is not grounded at one end? A. Hertz B. Marconi C. Dipole D. Whip
Last Answer : C. Dipole
Description : Which one is an antenna coupling unit? A. Coupler B. Diplexer C. Lecher wire D. Duplexer
Last Answer : B. Diplexer
Description : One of the following makes an antenna physically long but electrically short A. Adding L in series B. Adding C in series C. Top loading D. Both A and C
Last Answer : B. Adding C in series
Description : One of the following is not a reason for the use of an earth mat A. impossibility of a good ground connection B. provision of an earth for the antenna C. protection of personnel working underneath D. improvement of the radiation pattern of the antenna
Last Answer : C. protection of personnel working underneath
Description : Which antenna is not a wideband? A. Discone B. Folded dipole C. Helical D. Marconi
Last Answer : D. Marconi
Description : Not a reason for the use of an antenna coupler. A. To make the antenna look resistive B. To provide the output amplifier with the correct load impedance C. To discriminate against harmonics D. To prevent re-radiation of the local oscillator
Last Answer : D. To prevent re-radiation of the local oscillator
Description : Indicate which of the following reasons for using metal counterpoise with antennas is false. A. Impossibly of a good ground connection B. Protection of personnel working underneath C. Provision of an earth for the antenna D. Rockiness of the ground itself
Last Answer : B. Protection of personnel working underneath
Description : One of the following is very useful as a multiband HF receiving antenna. A. Parabolic antenna B. Elementary doublet C. Log-periodic D. Square loop
Last Answer : C. Log-periodic