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amateurradio:decibel_s_reading

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amateurradio:decibel_s_reading [2018/10/31 13:25]
tplecko
amateurradio:decibel_s_reading [2018/10/31 13:27] (current)
tplecko
Line 27: Line 27:
  
 ===== HF S-meter ===== ===== HF S-meter =====
-Many amateur radio and shortwave broadcast receivers feature a signal strength meter (S‑meter).In 1981, the International Amateur Radio Union (IARU) Region 1 agreed on a technical recommendation for S‑meter calibration of HF and VHF/UHF transceivers.+Many amateur radio and shortwave broadcast receivers feature a signal strength meter (S‑meter). In 1981, the International Amateur Radio Union (IARU) Region 1 agreed on a technical recommendation for S‑meter calibration of HF and VHF/UHF transceivers.
  
 IARU Region 1 Technical Recommendation R.1 defines S9 for the HF bands to be a receiver input power of -73 dBm. This is a level of 50 µV at the receiver’s antenna input assuming the input impedance of the receiver is 50 Ω. IARU Region 1 Technical Recommendation R.1 defines S9 for the HF bands to be a receiver input power of -73 dBm. This is a level of 50 µV at the receiver’s antenna input assuming the input impedance of the receiver is 50 Ω.
  
-The recommendation defines a difference of one S-unit corresponds to a difference of 6 dB, equivalent to a voltage ratio of two, or a power ratio of four. Signals stronger than S9 are given with an additional dB rating, thus S9 + 20 dB, or, verbally, ​20 decibel over S9, or simply ​20 over 9” or even the simpler ​20 over.+The recommendation defines a difference of one S-unit corresponds to a difference of 6 dB, equivalent to a voltage ratio of two, or a power ratio of four. Signals stronger than S9 are given with an additional dB rating, thus "S9 + 20 dB", or, verbally, ​"20 decibel over S9", or simply ​"20 over 9" ​or even the simpler ​"20 over".
  
 ^Conversion between power and HF S-units^^^^ ^Conversion between power and HF S-units^^^^
amateurradio/decibel_s_reading.txt · Last modified: 2018/10/31 13:27 by tplecko