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en:century-21 [2021/12/26 11:21] – angelegt mben:century-21 [2021/12/26 11:29] (aktuell) – [Technical data] mb
Zeile 6: Zeile 6:
 {{:images:divers-century-21.jpg?600|Seiki Century-21}} {{:images:divers-century-21.jpg?600|Seiki Century-21}}
 ===== Technical data ===== ===== Technical data =====
-  * [[Principle]]: [[Double conversion superhet]], [[IF]] 2500 / 455 kHz / FM 10.7 MHz+  * [[Principle]]: [[Double conversion superhet]], [[IF]] 2500 / 455 kHz
   * [[Operation modes]]: [[A1]] with BFO, [[A3|AM (A3)]]   * [[Operation modes]]: [[A1]] with BFO, [[A3|AM (A3)]]
   * [[Frequency range]]: 0.5 - 30 MHz   * [[Frequency range]]: 0.5 - 30 MHz
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 Tuning takes some getting used to, with the need to operate MHZ and kHz tuning, preselector and band switch, and rapid frequency changes are tedious. If a signal weakens, it may really be the antenna signal that is poor according to the propagation conditions, or the maximum of the MHz signal is not correctly tuned, the preselector is slightly maladjusted, the RF gain is still reduced, etc., etc., etc. - so something is forgotten easily! Often the calibration of the kHz dial is off by one to three kHz, which can be corrected by re-adjusting L21. Tuning takes some getting used to, with the need to operate MHZ and kHz tuning, preselector and band switch, and rapid frequency changes are tedious. If a signal weakens, it may really be the antenna signal that is poor according to the propagation conditions, or the maximum of the MHz signal is not correctly tuned, the preselector is slightly maladjusted, the RF gain is still reduced, etc., etc., etc. - so something is forgotten easily! Often the calibration of the kHz dial is off by one to three kHz, which can be corrected by re-adjusting L21.
  
-{{ :images:divers-century-21-back.jpg?400|Seiki Century-21}} All in all, the Century-21 is a collector's set, suitable as a secondary receiver for DXers and a grateful victim as a starting point for experiences with modifications. I have encountered several Century-21s in poor condition at radio flea markets. The indestructibility of commercial range receivers, which display still correct to one kHz after years of operation and perform almost like on the first day, cannot be achieved with the price compromise of circuitry and manufacturing technology.+{{ :images:divers-century-21-back.jpg?400|Seiki Century-21}} All in all, the Century-21 is a collector's set, suitable as a secondary receiver for DXers and a grateful victim as a starting point for experiences with modifications. I have encountered several Century-21s in poor condition at radio flea markets. The ruggedness of commercial range receivers, which display still correct to one kHz after years of operation and perform almost like on the first day, cannot be achieved with the price compromise of circuitry and manufacturing technology.
  
 It remains to mention that the schematic and circuit of the [[Drake]] [SSR-1]] and especially the standard [[C-6500]] are very, very similar to the Century-21. It remains to mention that the schematic and circuit of the [[Drake]] [SSR-1]] and especially the standard [[C-6500]] are very, very similar to the Century-21.
en/century-21.1640514118.txt.gz · Zuletzt geändert: 2021/12/26 11:21 von mb