Extra Exam-Operating Procedures e2

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Extra Exam-Operating Procedures e2
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Amateur Radio Extra Exam - E2 Question Set - Operating Procedures
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  1. E2A01 What is the direction of an ascending pass for an amateur satellite?
    A. From west to east
    B. From east to west
    C. From south to north
    D. From north to south
    • (C)
    • If the satellite is moving from south to north as it passes over your area, then it is making an ascending pass. The figure illustrates basic satellite orbital terminology.
  2. E2A02 What is the direction of a descending pass for an amateur satellite?
    A. From north to south
    B. From west to east
    C. From east to west
    D. From south to north
    • (A)
    • If the satellite is moving from north to south as it passes over your area, then it is making an descending pass.
  3. E2A03 What is the orbital period of an Earth satellite?
    A. The point of maximum height of a satellite's orbit
    B. The point of minimum height of a satellite's orbit
    C. The time it takes for a satellite to complete one revolution around the Earth
    D. The time it takes for a satellite to travel from perigee to apogee
    • (C)
    • The orbital period of a satellite is the time it takes that satellite to complete one orbit.
  4. E2A04 What is meant by the term mode as applied to an amateur radio satellite?
    A. The type of signals that can be relayed through the satellite
    B. The satellite's uplink and downlink frequency bands
    C. The satellite's orientation with respect to the Earth
    D. Whether the satellite is in a polar or equatorial orbit
    • (B)
    • The word “mode” is a bit overloaded when it comes to satellites. When referring to the satellite itself and not the type of signals it relays, mode refers to how the satellite’s uplink and downlink frequencies are configured. Some satellites have only one mode, while others with multiple receivers and transmitters may be able to operate in several modes. Each frequency band is abbreviated by a single letter: VHF by V, UHF by U, L band by L, and so forth. The first letter specifies the uplink and the second letter specifies the downlink.
  5. E2A05 What do the letters in a satellite's mode designator specify?
    A. Power limits for uplink and downlink transmissions
    B. The location of the ground control station
    C. The polarization of uplink and downlink signals
    D. The uplink and downlink frequency ranges
    • (D)
    • The word “mode” is a bit overloaded when it comes to satellites. When referring to the satellite itself and not the type of signals it relays, mode refers to how the satellite’s uplink and downlink frequencies are configured. Some satellites have only one mode, while others with multiple receivers and transmitters may be able to operate in several modes. Each frequency band is abbreviated by a single letter: VHF by V, UHF by U, L band by L, and so forth. The first letter specifies the uplink and the second letter specifies the downlink.
  6. E2A06 On what band would a satellite receive signals if it were operating in mode U/V?
    A. 435-438 MHz
    B. 144-146 MHz
    C. 50.0-50.2 MHz
    D. 29.5 to 29.7 MHz
    • (A)
    • The word “mode” is a bit overloaded when it comes to satellites. When referring to the satellite itself and not the type of signals it relays, mode refers to how the satellite’s uplink and downlink frequencies are configured. Some satellites have only one mode, while others with multiple receivers and transmitters may be able to operate in several modes. Each frequency band is abbreviated by a single letter: VHF by V, UHF by U, L band by L, and so forth. The first letter of a mode descriptor indicates the uplink frequency band, so U/V is the UHF uplink and VHF downlink mode. The 432 MHz band includes the frequencies for satellite uplinks.
  7. E2A07 Which of the following types of signals can be relayed through a linear transponder?
    A. FM and CW
    B. SSB and SSTV
    C. PSK and Packet
    D. All of these choices are correct
    • (D)
    • By convention, transponder is the name given to a linear translator that is installed in a satellite. It is somewhat like a repeater in that both devices receive signals and retransmit them. A repeater does that for signals of a single mode on a single frequency. By contrast, a transponder’s receive passband includes enough spectrum for many channels. The satellite transponder translates (or converts the frequency of) all signals in its passband — regardless of mode — and amplifies them and retransmits them in the new frequency range.
  8. E2A08 Why should effective radiated power to a satellite which uses a linear transponder be limited?
    A. To prevent creating errors in the satellite telemetry
    B. To avoid reducing the downlink power to all other users
    C. To prevent the satellite from emitting out of band signals
    D. To avoid interfering with terrestrial QSOs
    • (B)
    • Satellites have a very limited power supply consisting of solar cells and batteries. This means that the satellite downlink (transmit) transmitter power must be limited. Most satellites use linear transponders in which a strong signal on the uplink is also a strong signal on the downlink. If a satellite user’s ERP is too high, it can consume a disproportionate amount of the available transmit power. For that reason, satellite users should use the minimum transmitter output power needed to communicate through the satellite.
  9. E2A09 What do the terms L band and S band specify with regard to satellite communications?
    A. The 23 centimeter and 13 centimeter bands
    B. The 2 meter and 70 centimeter bands
    C. FM and Digital Store-and-Forward systems
    D. Which sideband to use
    • (A)
    • Instead of wavelength, microwave bands are designated by a letter. The Amateur Radio 23 cm band (1296 MHz) is part of the industry-designated L band. The Amateur Radio 13 cm band (2.4 GHz) is part of the industry-designated S band.
  10. E2A10 Why may the received signal from an amateur satellite exhibit a rapidly repeating fading effect?
    A. Because the satellite is spinning
    B. Because of ionospheric absorption
    C. Because of the satellite's low orbital altitude
    D. Because of the Doppler Effect
    • (A)
    • Satellite designers usually spin a satellite to improve the stability of its orientation. Of course the satellite antennas spin too, and this results in a fairly rapid pulsed fading effect. This effect is called spin modulation.
  11. E2A11 What type of antenna can be used to minimize the effects of spin modulation and Faraday rotation?
    A. A linearly polarized antenna
    B. A circularly polarized antenna
    C. An isotropic antenna
    D. A log-periodic dipole array
    • (B)
    • Satellite designers usually spin a satellite to improve the stability of its orientation. Of course the satellite antennas spin too, and this results in a fairly rapid pulsed fading effect. This effect is called spin modulation. Circularly polarized antennas of the proper sense (direction of polarization rotation) will minimize the effects of spin modulation. The polarization of a radio signal passing through the ionosphere does not remain constant. A horizontally polarized signal leaving a satellite will not be horizontally polarized after it passes through the ionosphere on its way to Earth. That signal will in fact seem to be changing polarization at a receiving station. This effect is called Faraday rotation. The best way to compensate for Faraday rotation is to use circularly polarized antennas for transmitting and receiving.
  12. E2A12 What is one way to predict the location of a satellite at a given time?
    A. By means of the Doppler data for the specified satellite
    B. By subtracting the mean anomaly from the orbital inclination
    C. By adding the mean anomaly to the orbital inclination
    D. By calculations using the Keplerian elements for the specified satellite
    • (D)
    • Johannes Kepler described the planetary orbits of our solar system. The laws and mathematical formulas that he developed may be used to calculate the location of a satellite at a given time. By using as input the values of a set of measurements describing the satellite orbit, called Keplerian elements, computer software can determine the location of the satellite.
  13. E2A13 What type of satellite appears to stay in one position in the sky?
    A. HEO
    B. Geostationary
    C. Geomagnetic
    D. LEO
    • (B)
    • The orbital period of a geosynchronous satellite is the same as the Earth’s period of rotation about its axis. As a result, the satellite stays above the same spot on the Earth’s surface, revolving around the Earth’s axis at the same rate as the Earth’s rotation.
  14. E2B01 How many times per second is a new frame transmitted in a fast-scan (NTSC) television system?
    A. 30
    B. 60
    C. 90
    D. 120
    • (A)
    • A picture is divided sequentially into pieces for transmission or viewing; this process is called scanning. A total of 525 scan lines comprise a frame (complete picture) in the US television system. Thirty frames are generated each second.
  15. E2B02 How many horizontal lines make up a fast-scan (NTSC) television frame?
    A. 30
    B. 60
    C. 525
    D. 1080
    • (C)
    • A picture is divided sequentially into pieces for transmission or viewing; this process is called scanning. A total of 525 scan lines comprise a frame (complete picture) in the US television system. Thirty frames are generated each second. A total of 525 horizontal lines make up a fast-scan television frame (complete picture).
  16. E2B03 How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?
    A. By scanning two fields simultaneously
    B. By scanning each field from bottom to top
    C. By scanning lines from left to right in one field and right to left in the next
    D. By scanning odd numbered lines in one field and even numbered ones in the next
    • (D)
    • A picture is divided sequentially into pieces for transmission or viewing; this process is called scanning. A total of 525 scan lines comprise a frame (complete picture) in the US television system. Thirty frames are generated each second. The fast-scan TV frame consists of two fields of 262-1/2 lines each. The odd numbered lines are scanned in one field and the even numbered ones are scanned in the next. The half line is the secret to the interlaced scan pattern. This is illustrated in the drawing that shows the interlaced scanning used in TV. In field one, 262-1⁄2 lines are scanned (A). At the end of field one, the electron scanning beam is returned to the top of the picture area (B). Scanning lines in field two (C) fall between the lines of field one. At the end of field two, the scanning beam is again returned to the top, where scanning continues with field one (D).
  17. E2B04 What is blanking in a video signal?
    A. Synchronization of the horizontal and vertical sync pulses
    B. Turning off the scanning beam while it is traveling from right to left or from bottom to top
    C. Turning off the scanning beam at the conclusion of a transmission
    D. Transmitting a black and white test pattern
    • (B)
    • The function of blanking is to turn off the scanning beam while the beam is traveling from right to left and from bottom to top. The blanking signal occurs at the end of each scan line and at the end of each scan field. In terms of video brightness, blanking is “blacker than black” so that the blanked beam will not affect the image as it travels across it.
  18. E2B05 (C)Which of the following is an advantage of using vestigial sideband for standard fast- scan TV transmissions?
    A. The vestigial sideband carries the audio information
    B. The vestigial sideband contains chroma information
    C. Vestigial sideband reduces bandwidth while allowing for simple video detector circuitry
    D. Vestigial sideband provides high frequency emphasis to sharpen the picture
    • (C)
    • The frequency spectrum of a color fast-scan TV signal is shown in part A. The vestigial sideband is to the left of the line labeled “Picture Carrier” and occupies a bandwidth of 1.25 MHz. Part B shows the spectrum analyzer view of a typical fast-scan TV signal. Including a vestigial sideband (see the next question) allows the video signal to be recovered with simple AM detector circuits, as opposed to requiring the more complex SSB demodulators. By only including part of the unused sideband, the full bandwidth of an AM-DSB signal is not required.
  19. E2B06 What is vestigial sideband modulation?
    A. Amplitude modulation in which one complete sideband and a portion of the other are transmitted
    B. A type of modulation in which one sideband is inverted
    C. Narrow-band FM transmission achieved by filtering one sideband from the audio before frequency modulating the carrier
    D. Spread spectrum modulation achieved by applying FM modulation following single sideband amplitude modulation
    • (A)
    • The frequency spectrum of a color fast-scan TV signal is shown in part A. The vestigial sideband is to the left of the line labeled “Picture Carrier” and occupies a bandwidth of 1.25 MHz. Part B shows the spectrum analyzer view of a typical fast-scan TV signal. Vestigial means partial and unused, and the vestigial sideband of a fast-scan TV signal is attenuated and reduced in bandwidth from the full-bandwidth sideband that carries the video information. Its only function is to allow the transmitted signal to be detected as an AM signal, instead of SSB.
  20. E2B07 What is the name of the signal component that carries color information in NTSC video?
    A. Luminance
    B. Chroma
    C. Hue
    D. Spectral Intensity
    • (B)
    • Also referred to as chrominance, the chroma signal is combined with the basic monochrome (black and white) TV signal.
  21. E2B08 Which of the following is a common method of transmitting accompanying audio with amateur fast-scan television?
    A. Frequency-modulated sub-carrier
    B. A separate VHF or UHF audio link
    C. Frequency modulation of the video carrier
    D. All of these choices are correct
    • (D)
    • The first choice is how commercial stations transmit the audio information in a TV signal. The second is the way most hams send ATV audio because it is easier than adding an FM signal to the transmitted video signal. The third choice is another popular method of adding audio information without affecting the AM video components
  22. E2B09 What hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM)?
    A. A special IF converter
    B. A special front end limiter
    C. A special notch filter to remove synchronization pulses
    D. No other hardware is needed
    • (D)
    • Digital Radio Mondiale was developed for transmitting digital audio information and data over shortwave broadcast channels. Hams adapted it to transmit SSTV pictures as digital data. The demodulated audio from a DRM signal can be processed by computer sound card, recovering the picture information.
  23. E2B10 Which of the following is an acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands?
    A. 3 KHz
    B. 10 KHz
    C. 15 KHz
    D. 20 KHz
    • (A)
    • Image transmissions are allowed in phone band segments if their bandwidth is no greater than that of a voice signal of the same modulation type. For SSB transmissions, the normal bandwidth is 3 kHz.
  24. E2B11 What is the function of the Vertical Interval Signaling (VIS) code transmitted as part of an SSTV transmission?
    A. To lock the color burst oscillator in color SSTV images
    B. To identify the SSTV mode being used
    C. To provide vertical synchronization
    D. To identify the call sign of the station transmitting
    • (B)
    • There are a number of different formats in which SSTV images are transmitted. So that automated receiving systems can determine which format is being used, identifying codes are transmitted during the vertical blanking period between images. This is called Vertical Interval Signaling (VIS).
  25. E2B12 How are analog SSTV images typically transmitted on the HF bands?
    A. Video is converted to equivalent Baudot representation
    B. Video is converted to equivalent ASCII representation
    C. Varying tone frequencies representing the video are transmitted using PSK
    D. Varying tone frequencies representing the video are transmitted using single sideband
    • (D)
    • The standard method of transmitting analog SSTV on the HF bands uses an SSB transmitter. The raster control signals, such as horizontal and vertical sync pulses, and image video are encoded as different tones that are transmitted as regular audio over the SSB channel.
  26. E2B13 How many lines are commonly used in each frame on an amateur slow-scan color television picture?
    A. 30 to 60
    B. 60 or 100
    C. 128 or 256
    D. 180 or 360
    • (C)
    • Color SSTV standards specify either 128 or 256 lines per frame depending on the selected transmission format.
  27. E2B14 What aspect of an amateur slow-scan television signal encodes the brightness of the picture?
    A. Tone frequency
    B. Tone amplitude
    C. Sync amplitude
    D. Sync frequency
    • (A)
    • Because HF signals experience frequent fading, amplitude is not used to encode the SSTV signal. Frequency of the received tones is unaffected by fading, however, and can be used to encode brightness or any control function of the signal
  28. E2B15 What signals SSTV receiving equipment to begin a new picture line?
    A. Specific tone frequencies
    B. Elapsed time
    C. Specific tone amplitudes
    D. A two-tone signal
    • (A)
    • The standard method of transmitting analog SSTV on the HF bands uses an SSB transmitter. The raster control signals, such as horizontal and vertical sync pulses, and image video are encoded as different tones that are transmitted as regular audio over the SSB channel.
  29. E2B16 Which of the following is the video standard used by North American Fast Scan ATV stations?
    A. PAL
    B. DRM
    C. Scottie
    D. NTSC
    • (D)
    • NTSC stands for National Television Standard Committee and is the standard for analog commercial television broadcasters, as well. The NTSC standard describes all aspects of the television signal.
  30. E2B17 What is the approximate bandwidth of a slow-scan TV signal?
    A. 600 Hz
    B. 3 kHz
    C. 2 MHz
    D. 6 MHz
    • (B)
    • Image transmissions are allowed in phone band segments if their bandwidth is no greater than that of a voice signal of the same modulation type. For SSB transmissions, the normal bandwidth is 3 kHz.
  31. E2B18 On which of the following frequencies is one likely to find FM ATV transmissions?
    A. 14.230 MHz
    B. 29.6 MHz
    C. 52.525 MHz
    D. 1255 MHz
    • (D)
    • Because the bandwidth of FM ATV signals is so wide (approximately 12 MHz), its use is restricted to UHF and higher bands.
  32. E2B19 What special operating frequency restrictions are imposed on slow scan TV transmissions?
    A. None; they are allowed on all amateur frequencies
    B. They are restricted to 7.245 MHz, 14.245 MHz, 21.345, MHz, and 28.945 MHz
    C. They are restricted to phone band segments and their bandwidth can be no greater than that of a voice signal of the same modulation type
    D. They are not permitted above 54 MHz
    • (C)
    • Image transmissions are allowed in phone band segments if their bandwidth is no greater than that of a voice signal of the same modulation type. For SSB transmissions, the normal bandwidth is 3 kHz.
  33. E2C01 Which of the following is true about contest operating?
    A. Operators are permitted to make contacts even if they do not submit a log
    B. Interference to other amateurs is unavoidable and therefore acceptable
    C. It is mandatory to transmit the call sign of the station being worked as part of every transmission to that station
    D. Every contest requires a signal report in the exchange
    • (A)
    • With very few exceptions, contests are open to all amateurs.. In addition, stations participating in the contest may count contacts with you even if you do not send the event sponsor a log of your contest activity. Just ask the contest station what information they need to complete the contact and they’ll tell you.
  34. E2C02 Which of the following best describes the term “self-spotting” in regards to contest operating?
    A. The generally prohibited practice of posting one’s own call sign and frequency on a call sign spotting network
    B. The acceptable practice of manually posting the call signs of stations on a call sign spotting network
    C. A manual technique for rapidly zero beating or tuning to a station’s frequency before calling that station
    D. An automatic method for rapidly zero beating or tuning to a station’s frequency before calling that station
    • (A)
    • A “spot” is an announcement that a specific station is present on a specific frequency. Spots are distributed mostly over the Internet via websites and TELNET-based “clusters” that form a worldwide spotting network. Posting your own frequency and call sign — self-spotting — in an attempt to get more contacts is prohibited.
  35. E2C03 From which of the following bands is amateur radio contesting generally excluded?
    A. 30 meters
    B. 6 meters
    C. 2 meters
    D. 33 cm
    • (A)
    • By general agreement, 60, 30, 17 and 12 meters are excluded from contest activity. This gives stations not interested in the contest an additional option for avoiding contest activity.
  36. E2C04 On which of the following frequencies is an amateur radio contest contact generally discouraged?
    A. 3.525 MHz
    B. 14.020 MHz
    C. 28.330 MHz
    D. 146.52 MHz
    • (D)
    • The national simplex calling channels of 146.52, 223.5 and 446.0 MHz are generally excluded from contest activity. This keeps them useful for establishing local contacts.
  37. E2C05 What is the function of a DX QSL Manager?
    A. To allocate frequencies for DXpeditions
    B. To handle the receiving and sending of confirmation cards for a DX station
    C. To run a net to allow many stations to contact a rare DX station
    D. To relay calls to and from a DX station
    • (B)
    • Because of the expense of postage and the effort required to answer a lot of QSL requests, many DX stations enlist the aid of a manager in the U.S., Europe, Japan or another area with good postal service. QSL cards are sent directly to the manager without the DX station having to take time out from operating. This practice generally saves on postage for the station sending the confirmation, as well.
  38. E2C06 During a VHF/UHF contest, in which band segment would you expect to find the highest level of activity?
    (A) In the middle of each band, usually on the national calling frequency
    (B) In the middle of the band, usually 25 kHz above the national calling frequency
    (C) At the top of each band, usually in a segment reserved for contests
    (D) In the weak signal segment of the band, with most of the activity near the calling frequency
    (D)
    Most contest activity on the VHF and UHF bands is SSB or CW, referred to as “weak signal” because these modes perform better than FM at low signal-to-noise ratios. The usual convention for contest activity is to call CQ on or near the calling frequency and then move to a nearby frequency once activity builds. In populated areas, calling CQ on the calling frequency is discouraged so that stations will spread out.
    (this multiple choice question has been scrambled)
  39. E2C07 What is the Cabrillo format?
    A. A standard for submission of electronic contest logs
    B. A method of exchanging information during a contest QSO
    C. The most common set of contest rules
    D. The rules of order for meetings between contest sponsors
    • (A)
    • Named for Cabrillo College near Santa Cruz, California, the Cabrillo format standard specifies how log information in text form is organized for submission to the contest sponsor. It does not control how logs are checked or scored by the sponsor.
  40. E2C08 Why are received spread-spectrum signals resistant to interference?
    A. Signals not using the spectrum-spreading algorithm are suppressed in the receiver
    B. The high power used by a spread-spectrum transmitter keeps its signal from being easily overpowered
    C. The receiver is always equipped with a digital blanker circuit
    D. If interference is detected by the receiver it will signal the transmitter to change frequencies
    • (A)
    • Because the spread-spectrum signal changes frequencies rapidly, interference or noise on a single frequency affects it only briefly. To interfere with a spread-spectrum signal, interference would have to follow the changing frequency exactly or cover a significant fraction of the band it occupies.
  41. E2C09 How does the spread-spectrum technique of frequency hopping work?
    A. If interference is detected by the receiver it will signal the transmitter to change frequencies
    B. If interference is detected by the receiver it will signal the transmitter to wait until the frequency is clear
    C. A pseudo-random binary bit stream is used to shift the phase of an RF carrier very rapidly in a particular sequence
    D. The frequency of the transmitted signal is changed very rapidly according to a particular sequence also used by the receiving station
    • (D)
    • Frequency hopping (FH) is a form of spread spectrum in which the center frequency of a conventional carrier is altered many times per second in accordance with a list of frequency channels. The same frequency list is used by the receiving station, so it “hops” in sync with the transmitter.
  42. E2C10 Why might a DX station state that they are listening on another frequency?
    A. Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
    B. To separate the calling stations from the DX station
    C. To reduce interference, thereby improving operating efficiency
    D. All of these choices are correct
    • (D)
    • By transmitting on one frequency and listening on another (split frequency operation) when many stations are calling, it is much easier for the callers to hear the DX station. This allows everyone to follow instructions and makes the operation much more efficient. If you hear a DX station working callers you can’t hear, tune around to see if you can find the callers on a nearby frequency — usually above that of the DX station.
  43. E2C11 How should you generally identify your station when attempting to contact a DX station working a pileup or in a contest?
    A. Send your full call sign once or twice
    B. Send only the last two letters of your call sign until you make contact
    C. Send your full call sign and grid square
    D. Send the call sign of the DX station three times, the words this is, then your call sign three times
    • (A)
    • When the other operator sends CQ or QRZ? (Who is calling me?), this is your cue to call by sending your full call sign. Sending only part of your call sign is not a proper way to identify your station.
  44. E2C12 What might help to restore contact when DX signals become too weak to copy across an entire HF band a few hours after sunset?
    A. Switch to a higher frequency HF band
    B. Switch to a lower frequency HF band
    C. Wait 90 minutes or so for the signal degradation to pass
    D. Wait 24 hours before attempting another communication on the band
    • (B)
    • The “weak and fluttery after sunset” condition indicates that the band conditions are deteriorating. You can continue to operate by changing frequencies. In this case, you’ll want to operate at a lower frequency because the MUF has moved lower as well.
  45. E2D01 Which of the following digital modes is especially designed for use for meteor scatter signals?
    A. WSPR
    B. FSK441
    C. Hellschreiber
    D. APRS
    • (B)
    • The WSJT suite of software written by Joe Taylor, K1JT includes several digital modes optimized for special operating modes such as moonbounce (EME), meteor scatter, low-power beacons, and more. FSK441 uses multi-frequency-shift keying using four tones at a data rate of 441 baud.
  46. E2D02 What is the definition of baud?

    A. The number of data symbols transmitted per second
    B. The number of characters transmitted per second
    C. The number of characters transmitted per minute
    D. The number of words transmitted per minute
    • (A)
    • A baud is a single signaling event between the data link’s transmitter and receiver. Each signaling event transmits one symbol. A symbol can encode one or more bits. The rate at which signaling events occur is called baud or bauds.
  47. E2D03 Which of the following digital modes is especially useful for EME communications?
    A. FSK441
    B. PACTOR III
    C. Olivia
    D. JT65
    • (D)
    • The WSJT suite of software written by Joe Taylor, K1JT includes several digital modes optimized for special operating modes such as moonbounce (EME), meteor scatter, low-power beacons, and more. JT65 is optimized for use at the extremely low signal-to-noise ratios and long transit times encountered in EME communications.
  48. E2D04 What is the purpose of digital store-and-forward functions on an Amateur Radio satellite?
    A. To upload operational software for the transponder
    B. To delay download of telemetry between satellites
    C. To store digital messages in the satellite for later download by other stations
    D. To relay messages between satellites
    • (C)
    • Digital communications satellites provide non-real-time computer-to-computer communications. Since satellites in low Earth orbit (LEO) cannot see large segments of the world at once, these satellites work like temporary mailboxes in space. You upload a message or a file to a satellite and it is stored for a time (could be days or weeks) until someone else — possibly on the other side of the world — downloads it. Messages or files can be sent to an individual recipient or everyone. Such communications are called store-and-forward.
  49. E2D05 Which of the following techniques is normally used by low Earth orbiting digital satellites to relay messages around the world?
    A. Digipeating
    B. Store-and-forward
    C. Multi-satellite relaying
    D. Node hopping
    • (B)
    • Digital communications satellites provide non-real-time computer-to-computer communications. Since satellites in low Earth orbit (LEO) cannot see large segments of the world at once, these satellites work like temporary mailboxes in space. You upload a message or a file to a satellite and it is stored for a time (could be days or weeks) until someone else — possibly on the other side of the world — downloads it. Messages or files can be sent to an individual recipient or everyone. Such communications are called store-and-forward.
  50. E2D06 Which of the following is a commonly used 2-meter APRS frequency?
    A. 144.39 MHz
    B. 144.20 MHz
    C. 145.02 MHz
    D. 146.52 MHz
    • (A)
    • The common 2 meter Automatic Packet Reporting System (APRS) frequency in North America is 144.39 MHz.
  51. E2D07 Which of the following digital protocols is used by APRS?
    A. PACTOR
    B. 802.11
    C. AX.25
    D. AMTOR
    • (C)
    • The APRS system is constructed to use the amateur AX.25 packet protocol.
  52. E2D08 Which of the following types of packet frames is used to transmit APRS beacon data?
    A. Unnumbered Information
    B. Disconnect
    C. Acknowledgement
    D. Connect
    • (A)
    • The APRS system is constructed to use the amateur AX.25 packet protocol. To simplify the communication between stations, an APRS beacon is transmitted as an unnumbered information (UI) frame. The stations in an APRS network are not “connected” in the normal packet radio sense. The beacon frames are not directed to a specific station, and receiving stations do not acknowledge correct receipt of the frames.
  53. E2D09 Under clear communications conditions, which of these digital communications modes has the fastest data throughput?
    A. AMTOR
    B. 170-Hz shift, 45 baud RTTY
    C. PSK31
    D. 300-baud packet
    • (D)
    • For fastest throughput under clear communications conditions (assumed to be error-free transmission), the highest data rate is needed. Of the choices given, 300-baud packet has the highest data rate and, therefore, the fastest data throughput of these choices.
  54. E2D10 How can an APRS station be used to help support a public service communications activity?
    A. An APRS station with an emergency medical technician can automatically transmit medical data to the nearest hospital
    B. APRS stations with General Personnel Scanners can automatically relay the participant numbers and time as they pass the check points
    C. An APRS station with a GPS unit can automatically transmit information to show a mobile station's position during the event
    D. All of these choices are correct
    • (C)
    • In the Automatic Packet Reporting System, positions of fixed stations can be entered directly into software. Mobile APRS stations equipped with a GPS (Global Positioning System) unit can automatically transmit information to show the station’s position. This capability can be useful in support of a public service communications activity, such as a walk-a-thon.
  55. E2D11 Which of the following data are used by the APRS network communicate your location?
    A. Polar coordinates
    B. Time and frequency
    C. Radio direction finding LOPs
    D. Latitude and longitude
    • (D)
    • Many TNCs used for APRS have a serial port that can be connected directly to the data output jack of a GPS receiver. Software in the TNC recognizes the NMEA-0183 format and automatically extracts the latitude and longitude information for transmission over the APRS network. If the GPS receiver is not connected directly to the TNC, an operator can enter the information manually.
  56. E2D12 How does JT65 improve EME communications?
    A.  It can decode signals many dB below the noise floor using FEC
    B.  It controls the receiver to track Doppler shift
    C.  It supplies signals to guide the antenna to track the Moon
    D. All of these choices are correct
    • (A)
    • The forward error correcting codes (FEC) used by JT65 and precisely controlled timing and frequencies of the signals allows JT65 processing software to recover very weak signals error-free. Using JT65 allows much smaller stations to make EME contacts than if they were to use an analog mode such as CW or SSB that are copied “by ear.”
  57. E2E01 Which type of modulation is common for data emissions below 30 MHz?
    A. DTMF tones modulating an FM signal
    B. FSK
    C. Pulse modulation
    D. Spread spectrum
    • (B)
    • The most common method of transmitting data emissions below 30 MHz is by FSK (frequency-shift keying) of an RF carrier using an SSB transceiver.
  58. E2E02 What do the letters FEC mean as they relate to digital operation?
    A. Forward Error Correction
    B. First Error Correction
    C. Fatal Error Correction
    D. Final Error Correction
    • (A)
    • The telecommunications industry uses FEC as a standard acronym for Forward Error Correction. FEC involves the use of sending redundant data or special codes with the data so that the receiving system can compensate for errors that occur during transmission and reception
  59. E2E03 (C)How is Forward Error Correction implemented?
    A. By the receiving station repeating each block of three data characters
    B. By transmitting a special algorithm to the receiving station along with the data characters
    C. By transmitting extra data that may be used to detect and correct transmission errors
    D. By varying the frequency shift of the transmitted signal according to
    a predefined algorithm
    • (C)
    • This is a general question about Forward Error Correction systems. These systems do not require receiving stations to transmit an acknowledgement to the sending station. FEC is implemented by transmitting extra data that may be used to detect and correct transmission errors.
  60. E2E04 What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears?
    A. Selective fading has occurred
    B. One of the signal filters has saturated
    C. The receiver has drifted 5 kHz from the desired receive frequency
    D. The mark and space signal have been inverted
    • (A)
    • A common tuning aid for digital FSK signals uses a crossed pair of ellipses. Each ellipse represents one of the two tones being sent. With the propagation effect known as selective fading, a small region of the radio spectrum undergoes a deep fade as if a narrow filter has been applied to it. This is what can make one of the ellipses on the terminal unit display disappear.
  61. E2E05 How does ARQ accomplish error correction?
    A. Special binary codes provide automatic correction
    B. Special polynomial codes provide automatic correction
    C. If errors are detected, redundant data is substituted
    D. If errors are detected, a retransmission is requested
    • (D)
    • ARQ stands for Automatic Repeat reQuest. When an error is detected in received data, the ARQ receive system sends a NAK (Not Acknowledge) message back to the transmitting system so that the data is sent again.
  62. E2E06 What is the most common data rate used for HF packet communications?
    A. 48 baud
    B. 110 baud
    C. 300 baud
    D. 1200 baud
    • (C)
    • The most common data rate used for HF packet communications is 300 baud. Slower signaling rates are used for RTTY and higher rates are not permitted by regulation because they require more bandwidth.
  63. E2E07 What is the typical bandwidth of a properly modulated MFSK16 signal?
    A. 31 Hz
    B. 316 Hz
    C. 550 Hz
    D. 2.16 kHz
    • (B)
    • MFSK16 uses 16 tones, which are sent one at a time at 15.625 baud. Because the 16 tones are spaced 15.625 Hz apart, a properly modulated MFSK16 signal has a bandwidth of 316 Hz.
  64. E2E08 Which of the following HF digital modes can be used to transfer binary files?
    A. Hellschreiber
    B. PACTOR
    C. RTTY
    D. AMTOR
    • (B)
    • PACTOR was developed to combine the best features of packet radio and AMTOR. Since PACTOR carries binary data, you can use this mode to transfer binary data files directly between stations. The other mode choices are not suitable for this purpose.
  65. E2E09 Which of the following HF digital modes uses variable-length coding for bandwidth efficiency?
    A. RTTY
    B. PACTOR
    C. MT63
    D. PSK31
    • (D)
    • Peter Martinez, G3PLX, invented Varicode as a way to improve the data rate of PSK31. In Varicode, the more common characters have shorter codes, just like in Morse code.
  66. E2E10 Which of these digital communications modes has the narrowest bandwidth?
    A. MFSK16
    B. 170-Hz shift, 45 baud RTTY
    C. PSK31
    D. 300-baud packet
    • (C)
    • PSK31 uses a data rate of 31.25 baud. This results in an RF signal that has a bandwidth of only 37.5 Hz! This is by far the narrowest bandwidth of any amateur digital communications mode.
  67. E2E11 What is the difference between direct FSK and audio FSK?
    A. Direct FSK applies the data signal to the transmitter VFO
    B. Audio FSK has a superior frequency response
    C. Direct FSK uses a DC-coupled data connection
    D. Audio FSK can be performed anywhere in the transmit chain
    • (A)
    • With the advent of direct digital synthesis (DDS) VFOs, many radios now feature a direct FSK input by which a digital signal can shift the VFO frequency directly. This often results in superior modulation characteristics that reduce data errors by the receiver.
  68. E2E12 Which type of digital communication does not support keyboard-to-keyboard operation?
    A. Winlink
    B. RTTY
    C. PSK31
    D. MFSK
    • (A)
    • Keyboard-to-keyboard operation refers to each character being transmitted and displayed as it is typed (RTTY, PSK31, MFSK) or after an end-of-line character is entered by the operator (Packet). Winlink is an email system that transmits entire files that are not displayed until the receiving operator opens and reads them.

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