ARRL day 8.txt

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ARRL day 8.txt
2014-04-14 11:10:06
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  1. Which of the following describes a simple dipole mounted so the conductor is parallel to the Earth's surface?
    A. A ground wave antenna
    B. A horizontally polarized antenna
    C. A rhombic antenna
    D. A vertically polarized antenna
  2. In which direction is the radiation strongest from a half-wave dipole antenna in free space?
    A. Equally in all directions
    B. Off the ends of the antenna
    C. Broadside to the antenna
    D. In the direction of the feedline
  3. What is the approximate length, in inches, of a 6 meter 1/2-wavelength wire dipole antenna?
    A. 6
    B. 50
    C. 112
    D. 236
  4. How would you change a dipole antenna to make it resonant on a higher frequency?
    A. Lengthen it
    B. Insert coils in series with radiating wires
    C. Shorten it
    D. Add capacity hats to the ends of the radiating wires
  5. Which of the following is true regarding vertical antennas?
    A. The magnetic field is perpendicular to the Earth
    B. The electric field is perpendicular to the Earth
    C. The phase is inverted
    D. The phase is reversed
  6. What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz?
    A. 112
    B. 50
    C. 19
    D. 12
  7. What type of antennas are the quad, Yagi, and dish?
    A. Non-resonant antennas
    B. Loop antennas
    C. Directional antennas
    D. Isotropic antennas
  8. What is a beam antenna?
    A. An antenna built from aluminum I-beams
    B. An omnidirectional antenna invented by Clarence Beam
    C. An antenna that concentrates signals in one direction
    D. An antenna that reverses the phase of received signals
  9. Which of the following methods is used to locate sources of noise interference or jamming?
    A. Echolocation
    B. Doppler radar
    C. Radio direction finding
    D. Phase locking
  10. Which of these items would be useful for a hidden transmitter hunt?
    A. Calibrated SWR meter
    B. A directional antenna
    C. A calibrated noise bridge
    D. All of these choices are correct
  11. When using a directional antenna, how might your station be able to access a distant repeater if buildings or obstructions are blocking the direct line of sight path?
    A. Change from vertical to horizontal polarization
    B. Try to find a path that reflects signals to the repeater
    C. Try the long path
    D. Increase the antenna SWR
  12. What is meant by the gain of an antenna?
    A. The additional power that is added to the transmitter power
    B. The additional power that is lost in the antenna when transmitting on a higher frequency
    C. The increase in signal strength in a specified direction when compared to a reference antenna
    D. The increase in impedance on receive or transmit compared to a reference antenna
  13. What antenna polarization is normally used for long-distance weak-signal CW and SSB contacts using the VHF and UHF bands?
    A. Right-hand circular
    B. Left-hand circular
    C. Horizontal
    D. Vertical
  14. What can happen if the antennas at opposite ends of a VHF or UHF line of sight radio link are not using the same polarization?
    A. The modulation sidebands might become inverted
    B. Signals could be significantly weaker
    C. Signals have an echo effect on voices
    D. Nothing significant will happen
  15. Which of the following is a common use of coaxial cable?
    A. Carry dc power from a vehicle battery to a mobile radio
    B. Carry RF signals between a radio and antenna
    C. Secure masts, tubing, and other cylindrical objects on towers
    D. Connect data signals from a TNC to a computer
  16. Why is coaxial cable used more often than any other feedline for amateur radio antenna systems?
    A. It is easy to use and requires few special installation considerations
    B. It has less loss than any other type of feedline
    C. It can handle more power than any other type of feedline
    D. It is less expensive than any other types of feedline
  17. What is the impedance of the most commonly used coaxial cable in typical amateur radio installations?
    A. 8 ohms
    B. 50 ohms
    C. 600 ohms
    D. 12 ohms
  18. What generally happens as the frequency of a signal passing through coaxial cable is increased?
    A. The apparent SWR increases
    B. The reflected power increases
    C. The characteristic impedance increases
    D. The loss increases
  19. Which of the following is true of PL-259 type coax connectors?
    A. They are good for UHF frequencies
    B. They are water tight
    C. The are commonly used at HF frequencies
    D. They are a bayonet type connector
  20. Which of the following connectors is most suitable for frequencies above 400 MHz?
    A. A UHF (PL-259/SO-239) connector
    B. A Type N connector
    C. An RS-213 connector
    D. A DB-23 connector
  21. What is a disadvantage of "air core" coaxial cable when compared to foam or solid dielectric types?
    A. It has more loss per foot
    B. It cannot be used for VHF or UHF antennas
    C. It requires special techniques to prevent water absorption
    D. It cannot be used at below freezing temperatures
  22. Which of the following is the most common cause for failure of coaxial cables?
    A. Moisture contamination
    B. Gamma rays
    C. The velocity factor exceeds 1.0
    D. Overloading
  23. Why should coax connectors exposed to the weather be sealed against water intrusion?
    A. To prevent an increase in feedline loss
    B. To prevent interference to telephones
    C. To keep the jacket from becoming loose
    D. All of these choices are correct
  24. Why should the outer jacket of coaxial cable be resistant to ultraviolet light?
    A. Ultraviolet resistant jackets prevent harmonic radiation
    B. Ultraviolet light can increase losses in the cable’s jacket
    C. Ultraviolet and RF signals can mix together, causing interference
    D. Ultraviolet light can damage the jacket and allow water to enter the cable
  25. What electrical difference exists between the smaller RG-58 and larger RG-8 coaxial cables?
    A. There is no significant difference between the two types
    B. RG-58 cable has less loss at a given frequency
    C. RG-8 cable has less loss at a given frequency
    D. RG-58 cable can handle higher power levels
  26. Which of the following types of feedline has the lowest loss at VHF and UHF?
    A. 50-ohm flexible coax
    B. Multi-conductor unbalanced cable
    C. Air-insulated hard line
    D. 75-ohm flexible coax
  27. Which of the following instruments can be used to determine if an antenna is resonant at the desired operating frequency?
    A. A VTVM
    B. An antenna analyzer
    C. A "Q" meter
    D. A frequency counter
  28. What, in general terms, is standing wave ratio (SWR)?
    A. A measure of how well a load is matched to a transmission line
    B. The ratio of high to low impedance in a feedline
    C. The transmitter efficiency ratio
    D. An indication of the quality of your station’s ground connection
  29. Why is it important to have a low SWR in an antenna system that uses coaxial cable feedline?
    A. To reduce television interference
    B. To allow the efficient transfer of power and reduce losses
    C. To prolong antenna life
    D. All of these choices are correct
  30. What reading on an SWR meter indicates a perfect impedance match between the antenna and the feedline?
    A. 2 to 1
    B. 1 to 3
    C. 1 to 1
    D. 10 to 1
  31. What is the approximate SWR value above which the protection circuits in most solid-state transmitters begin to reduce transmitter power?
    A. 2 to 1
    B. 1 to 2
    C. 6 to 1
    D. 10 to 1
  32. What does an SWR reading of 4:1 mean?
    A. An antenna loss of 4 dB
    B. A good impedance match
    C. An antenna gain of 4
    D. An impedance mismatch
  33. What might cause erratic changes in SWR readings?
    A. The transmitter is being modulated
    B. A loose connection in an antenna or a feedline
    C. The transmitter is being over-modulated
    D. Interference from other stations is distorting your signal
  34. What instrument other than an SWR meter could you use to determine if a feedline and antenna are properly matched?
    A. Voltmeter
    B. Ohmmeter
    C. Iambic pentameter
    D. Directional wattmeter
  35. What happens to power lost in a feedline?
    A. It increases the SWR
    B. It comes back into your transmitter and could cause damage
    C. It is converted into heat
    D. It can cause distortion of your signal
  36. What does an antenna tuner do?
    A. It matches the antenna system impedance to the transceiver's output impedance
    B. It helps a receiver automatically tune in weak stations
    C. It allows an antenna to be used on both transmit and receive
    D. It automatically selects the proper antenna for the frequency band being used
  37. If figure T5 represents a transceiver in which block 1 is the transmitter portion and block 3 is the receiver portion, what is the function of block 2?
    A. A balanced modulator
    B. A transmit-receive switch
    C. A power amplifier
    D. A high-pass filter
  38. What is the primary purpose of a dummy load?
    A. To prevent the radiation of signals when making tests
    B. To prevent over-modulation of your transmitter
    C. To improve the radiation from your antenna
    D. To improve the signal to noise ratio of your receiver