SESKStuff Everyone Should Know

Games · Radio & Electronics

Stuff Every Extra Class Ham Should Know

Study the FCC Amateur Extra question pool one card at a time.

Start Stuff Every Extra Class Ham Should Know ⚡ Today's sprint

Print the first 50 cards (free)Get the whole test as a printable PDF: $3 (pre-order)

Free to start, no sign-up. 92 cards so far. One Knowledge Score and day streak across all your courses.

Try 3 cards

  1. Outside parts of Alaska, what is the maximum radiated power allowed on the 630 m amateur band?
    Show the answer

    5 W EIRP. Rule 97.313(l) caps 630 m at 500 W PEP from the transmitter and 5 W EIRP radiated. Stations in Alaska within 800 km of Russia are held to 1 W EIRP.

  2. How tall may an antenna used on the 2200 m and 630 m bands be above ground?
    Show the answer

    No more than 60 meters. Rule 97.15(c) says antennas used to transmit on the 2200 m and 630 m bands must not exceed 60 meters above ground level. That is about 197 feet.

  3. What is the maximum bandwidth an emission may occupy on the 60 m band?
    Show the answer

    2.8 kHz. Rule 97.303(h) says amateur emissions on 60 m may not occupy more than 2.8 kHz. That is about the width of one SSB voice signal or a typical digital mode.

All 92 practice questions

Each one has the answer, why it's right, and the official sources. Or play them as a game and track what you've learned.

Show all 92 questions
  1. Outside parts of Alaska, what is the maximum radiated power allowed on the 630 m amateur band?
  2. How tall may an antenna used on the 2200 m and 630 m bands be above ground?
  3. What is the maximum bandwidth an emission may occupy on the 60 m band?
  4. A remotely controlled station loses its control link. How long may it keep transmitting?
  5. What is the maximum transmitter power for amateur telecommand of a model craft?
  6. Who must approve an amateur station operating aboard a ship or aircraft?
  7. For a transmitter installed after January 1, 2003, below 30 MHz, how far below the fundamental must spurious emissions be?
  8. Antenna structures taller than what height above ground trigger FAA notification and FCC registration rules?
  9. After notifying the UTC, how long before you may begin operating on 630 m or 2200 m?
  10. Amateurs may not transmit north of Line A in which UHF segment?
  11. Besides an amateur license, what must a RACES control operator have?
  12. How many volunteer examiners must administer an amateur radio exam session?
  13. May an amateur telecommand station use special codes to obscure its commands to a space station?
  14. Outside the listed segments, an automatically controlled data station answering interrogation may use at most what bandwidth?
  15. How long is one FT8 transmit/receive sequence?
  16. How long is one WSPR transmitting period?
  17. Using MSK144 meteor scatter on VHF, about how far can contacts reach?
  18. What was the JT65 digital mode originally designed for?
  19. The Q65 mode is designed for which kind of signal conditions?
  20. In the ARRL 20 m band plan, which segment is assigned to RTTY?
  21. Which frequency does the ARRL 20 m band plan list for the NCDXF beacons?
  22. What does the ARRL 2 m band plan list as the National Simplex Calling Frequency?
  23. What does the maximum usable frequency (MUF) describe?
  24. What is sporadic E?
  25. What happens during a polar cap absorption event?
  26. Which ionospheric region exists in daytime, from about 40 to 90 km altitude?
  27. Each solar flare X-ray class (A, B, C, M, X) is how many times stronger than the one before?
  28. A solar flare of what class produces an R3 (Strong) radio blackout?
  29. On NOAA's scale, a G1 geomagnetic storm begins at what Kp value?
  30. The aurora is best seen under an oval between about which latitudes?
  31. About how long is the sunspot (solar) cycle?
  32. How soon can the fastest Earth-directed coronal mass ejections reach Earth?
  33. After one time constant, a charging capacitor holds about what fraction of its full charge?
  34. In a resonant circuit, what does a higher Q do to the bandwidth?
  35. At resonance, what is the impedance of a series RLC circuit?
  36. At resonance, what impedance does a parallel LC circuit present?
  37. At the half-power points of a resonant circuit, the current is what fraction of its maximum?
  38. In an ideal inductor, what is the phase relation between voltage and current?
  39. What happens to a capacitor's reactance as frequency rises?
  40. For maximum power transfer from a source, the load resistance should equal what?
  41. In what unit is reactive power measured?
  42. How much power do ideal inductors and capacitors dissipate?
  43. Gallium arsenide is a semiconductor material used mainly in what kind of circuits?
  44. How does the DC input impedance at a field-effect transistor gate compare with a bipolar transistor?
  45. Why are Zener diodes sometimes connected between a MOSFET gate and its source or drain?
  46. What is the most useful characteristic of a Zener diode?
  47. Which semiconductor device is designed to act as a voltage-controlled capacitor?
  48. What characteristic of a PIN diode makes it useful as an RF switch?
  49. What is tri-state logic?
  50. Why are the cores of inductors and transformers sometimes built from thin layers?
  51. What is a primary advantage of a toroidal core compared with a solenoidal core?
  52. What is the most common configuration of an optoisolator?
  53. How many flip-flops are needed to divide a signal's frequency by 16?
  54. Which circuit keeps switching between two states with no external clock signal?
  55. What is a Class D amplifier?
  56. Why are switching amplifiers more efficient than linear amplifiers?
  57. Which filter type has ripple in the passband and a sharp cutoff?
  58. Which filter type is used in a 2-meter repeater duplexer?
  59. How is battery operating time calculated?
  60. How do you calculate the power dissipated by a series linear voltage regulator?
  61. What are the principal frequencies at the output of a mixer?
  62. Which type of detector is used for demodulating SSB signals?
  63. How often must an analog signal be sampled to be accurately reproduced?
  64. What is the minimum number of bits to sample a 1-volt range at 1-millivolt resolution?
  65. An inverting op-amp circuit has a 1,800-ohm input resistor and a 68-kilohm feedback resistor. What is its absolute voltage gain?
  66. What is a phase-locked loop?
  67. What is the approximate ratio of peak envelope power to average power in an unprocessed SSB phone signal?
  68. How many different input levels can an 8-bit analog-to-digital converter encode?
  69. An FM signal deviates 3,000 Hz each side of the carrier with a highest modulating frequency of 1,000 Hz. What is the modulation index?
  70. What is the approximate bandwidth of a 13-WPM International Morse Code transmission?
  71. What is the bandwidth of an FT8 signal?
  72. How does ARQ accomplish error correction?
  73. Which digital code allows only one bit to change between sequential code values?
  74. Which describes spread spectrum frequency hopping?
  75. What is the most common method of reducing CW key clicks?
  76. What is an isotropic radiator?
  77. An antenna has 6 dB gain over an isotropic radiator. What is its gain over a half-wave dipole?
  78. Which of these frequency bands has the smallest first Fresnel zone?
  79. What is the effect of adding a terminating resistor to a rhombic or long-wire antenna?
  80. What is the approximate feed point impedance at the center of a two-wire half-wave folded dipole?
  81. How much does an ideal parabolic dish's gain increase when the operating frequency doubles?
  82. What happens as the Q of an antenna increases?
  83. Which matching system connects the coax shield to the antenna center and the conductor a fraction of a wavelength to one side?
  84. Which factor has the biggest effect on the velocity factor of a transmission line?
  85. About how long is an air-insulated parallel conductor line that is electrically a half wavelength at 14.10 MHz?
  86. What impedance does a quarter-wavelength transmission line present to the generator when shorted at the far end?
  87. What can be calculated using a Smith chart?
  88. What is the function of a Beverage antenna's termination resistor?
  89. Over what range of frequencies are the FCC human body RF exposure limits most restrictive?
  90. What does "100% tie-off" mean for tower safety?
  91. What does SAR measure?
  92. Where should a shock-absorbing lanyard be attached to a tower when working above ground?