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T4B10

AMATEUR RADIO PRACTICES · Operating controls: frequency tuning, use of filters, squelch function, AGC, memory channels, noise blanker, microphone gain, receiver incremental tuning (RIT), bandwidth selection, scanning function; Digital transceiver configuration; DMR code plugs and talk groups

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Which of the following receiver filter bandwidths provides the best signal-to-noise ratio for SSB reception?

  1. A500 Hz
  2. B1000 Hz
  3. C2400 Hz
  4. D5000 Hz
Why A receiver filter should be just wide enough to pass the signal and no wider, because every extra hertz of bandwidth admits more noise without adding any signal. A voice SSB transmission occupies roughly 2.4 kHz, so a 2400 Hz filter passes all of the speech energy while rejecting noise and adjacent signals outside it, giving the best signal-to-noise ratio.
Watch out The 500 Hz setting is a CW filter; it would chop off most of the speech energy and make SSB audio muffled and unintelligible, while 5000 Hz is about right for AM and just lets in twice the noise for an SSB signal.
Match the filter to the mode: about 500 Hz for CW, 2400 Hz for SSB, 5 kHz or more for AM/FM.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
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The rest of T4B

  1. T4B01 What is the effect of excessive microphone gain on SSB transmissions?
  2. T4B02 Which of the following can be used to enter a transceiver's operating frequency?
  3. T4B03 How is squelch adjusted so that a weak FM signal can be heard?
  4. T4B04 What does an FM signal sound like when received slightly off frequency?
  5. T4B05 What does the scanning function of an FM transceiver do?
  6. T4B06 Which of the following controls could be used if the voice pitch of a single-sideband signal returning to you…
  7. T4B07 What is a DMR "code plug"?
  8. T4B08 What is the advantage of having a choice of receiver filter bandwidths in a multimode transceiver?
  9. T4B09 How is a specific group of stations selected on a DMR digital voice transceiver?
  10. T4B10 Which of the following receiver filter bandwidths provides the best signal-to-noise ratio for SSB reception?
  11. T4B11 Which of the following must be programmed into a D-STAR digital transceiver before transmitting?
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