====== Century 21 Model 570 ======
{{570.jpg?150|}}

===== Description =====
Medium power solid state cw transceiver covering 80 - 10 meters.  Double direct conversion receiver.  Built-in AC power supply.

===== Reviews =====
  *[[http://www.eham.net/reviews/detail/503|eHam]]
  *[[http://p1k.arrl.org/cgi-bin/topdf.cgi?id=70763&pub=qst|Product Review, QST, 1977, December]] (Must be an ARRL member and logged in to view.)

===== Mods & Tips =====
  *[[https://web.archive.org/web/20080402235822/http://www.io.com:80/~n5fc/c21_pto.htm|Rebuilding the Century 21 PTO / Vernier]] by N5ESE
  *[[570humfix|Hum Fix]]
  *[[http://p1k.arrl.org/cgi-bin/topdf.cgi?id=73688&pub=qst|Semi-Break-In for the Century 21 - Hints & Kinks, QST, 1979, December]] (Must be an ARRL member and logged in to view.)

===== Sales Information =====
{{570_01_78.jpg?100|}}

===== Accessories =====
  *Keyer Model [[670]]
  *Calibrator Model [[276]]
  *Crystal for 21.0 - 21.5 MHz Model [[271]]
  *Crystal for 28.0 - 28.5 MHz Model [[272]]
  *Crystal for 28.5 - 29.0 MHz Model [[273]]
  *Digital Mod Kit Model [[274]]
  *DC Circuit Breaker Model [[1170]]

===== Specifications =====
==== General ====
  ***Frequency Coverage:** 3.5 to 4.0; 7.0 to 7.5; 14.0 to 14.5; 21.0 to 21.5; 28.0 to 28.5; 28.5 to 29.0 MHz. (Crystal not supplied for 28.5 to 29.0 MHz, but available as accessory, Model [[273]].) Note - Early models only included crystals for 3.5, 7, and 14 MHz bands. Crystals for 21 Mhz and 28 Mhz bands were available as optional Models numbers [[271]] and [[272]].
  ***VFO Frequency Stability:** less than 20 Hz change per degree Fahrenheit, averaged over a 40<sup>o</sup> change from 70<sup>o</sup> to 110<sup>o</sup>, after 30 minute warmup.  Less than 20 Hz change from 105 to 125 VAC line voltage.
  ***Direct Frequency Readout:** Marked in 5 kHz increments from 0 - 500 kHz, MHz markings for each band displayed.
  ***Tuning Rate:** Approximately 17 kHz per revolution of main tuning knob.
  ***Power Requirements:** 105 - 125 VAC, 50-60 Hz.  10 watts receive, 100 watts transmit.
  ***Semiconductors:** 25 transistors, 26 diodes, 5 integrated circuits.
  ***PC Boards:** 4 plug-in types, 6 integral.
  ***Construction:** Rigid aluminum chassis and sub-panels.  Aluminum case.  Grey front panel, black textured vinyl cover.
  ***Dimensions:** HWD 6.125" x 12.5" x 12"
  ***Weight:** 15.5 lbs

==== Receiver ====
  ***Sensitivity:** 1 uV or less for 10 dB S+N/N.
  ***Selectivity:** Three position; 0.5, 1.0, and 2.5 kHz.
  ***VFO Frequency:** 5.0 to 5.5 MHz.  Double Direct Conversion.
  ***Antenna Input:** 50 ohms, unbalanced.
  ***Audio Output:** 1 watt @ 8 ohms, less than 2% harmonic distortion.  Built-in speaker; PHONES jack.
  ***Offset Tuning:** Approximately +/- 5 kHz, defeatable with ZERO BEAT switch.

==== Transmitter ====
  ***DC Input Power:** 70 watts
  ***RF Output Power:** 25-30 watts, typical.
  ***Output Impedance:** 50 - 75 ohms, unbalanced.
  ***T/R Switching:** Full break-in cw with PIN diode switch.