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hambasics:sections:practice [2020/12/30 09:08] – created - external edit 127.0.0.1hambasics:sections:practice [2024/11/24 12:54] (current) – va7fi
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 ====== Recall ====== ====== Recall ======
-  * [[howto:hambasics:sections:wavemodulation#modulation|Modulation]]+  * [[hambasics:sections:wavemodulation#modulation|Modulation]]
  
 ====== Receivers ====== ====== Receivers ======
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   * If SNR < 1, then the noise is stronger than the signal.   * If SNR < 1, then the noise is stronger than the signal.
  
-Like other ratios, we often express SNR in [[howto:hambasics:sections:mathbasics#the_decibel|decibel]].  Recall that a ratio of 1 = 0 dB, so the above could be stated as:+Like other ratios, we often express SNR in [[hambasics:sections:mathbasics#the_decibel|decibel]].  Recall that a ratio of 1 = 0 dB, so the above could be stated as:
   * If SNR > 0 dB, then the signal is stronger than the noise.   * If SNR > 0 dB, then the signal is stronger than the noise.
   * If SNR = 0 dB, then the signal and the noise have the same strength.   * If SNR = 0 dB, then the signal and the noise have the same strength.
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 <WRAP center box 90%> <WRAP center box 90%>
-{{ howto:hambasics:sections:7300sensitivity.png }}+{{ hambasics:sections:7300sensitivity.png }}
 </WRAP> </WRAP>
  
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 ===== Selectivity ===== ===== Selectivity =====
-Recall from the [[howto:hambasics:sections:intro#bandwidth|intro section]] that radio signals always take up some bandwidth on the radio spectrum:+Recall from the [[hambasics:sections:intro#bandwidth|intro section]] that radio signals always take up some bandwidth on the radio spectrum:
   * [[wp>Continuous_wave |CW]] takes the least amount of "space" because it's essentially just a single note being turned on and off.  A 250 Hz filter would work well to isolate the signal and reject neighbouring signals.   * [[wp>Continuous_wave |CW]] takes the least amount of "space" because it's essentially just a single note being turned on and off.  A 250 Hz filter would work well to isolate the signal and reject neighbouring signals.
-  * [[wp>Radioteletype |RTTY]] is a [[howto:hambasics:sections:digitalconcepts|digital mode]] that uses two notes to represent 0s and 1s, thus it takes a little bit more space than CW.+  * [[wp>Radioteletype |RTTY]] is a [[hambasics:sections:digitalconcepts|digital mode]] that uses two notes to represent 0s and 1s, thus it takes a little bit more space than CW.
   * SSB signals usually have a bandwidth between 2 kHz and 3 kHz.  A 2.4 kHz filter would work well to isolate the signal and reject neighbouring signals.   * SSB signals usually have a bandwidth between 2 kHz and 3 kHz.  A 2.4 kHz filter would work well to isolate the signal and reject neighbouring signals.
   * FM, needs about 20 kHz, which is why FM radio stations sound better than AM radio stations.   * FM, needs about 20 kHz, which is why FM radio stations sound better than AM radio stations.
hambasics/sections/practice.1609348083.txt.gz · Last modified: 2020/12/30 09:08 by 127.0.0.1