====== Corsair II Model 561 ======
{{561.jpg?150|}}{{561rear.jpg?120|}}

===== Reviews =====
  *[[http://www.eham.net/reviews/detail/459|eHam]]
  *A review is available on the CQ Magazine pay-to-view Web site
  *A review is available on the ARRL Members Only Web site

===== Manual =====
  *[[http://corsair.wikidot.com/corsair-errata|Manual Errata]]
  *[[http://www.tentecwiki.org/lib/exe/fetch.php?media=corsair2NBa.gif|Corsair II Noise Blanker Schematic]]
===== Mods & Fixes =====
  *[[http://corsair.wikidot.com/corsair-afrx|Corsair Audio Mods]]
  *[[561bcimod|Broadcast Interference Fix]]
  *[[561relnoise|Relay Noise Mod]]
  *[[561intermled|Intermittent LED Fix]]
  *[[561audfilter|Audio Filter]]
  *[[561knobins|Knob Insert Replacements]]
  *[[561knobrepair|Knob Repair]]
  *[[561dispfix|Display Problem & Fix]]
  *[[561drift|Freq Drift - Offset Pot]]
  *[[561lpftr|Weak Receive on Higher Bands]] - LPF TR Board
  *{{corsair_qsk_mod.pdf|QSK Mod}} (Contributed by AB9M)
  *[[http://corsair.wikidot.com/corsair-9mhz|Socketing the 9Mhz Filter]]
  *[[http://corsair.wikidot.com/corsair-aftx|Balanced Modulator direct drive]]
  *[[http://corsair.wikidot.com/corsair-afrx|Detachable speaker wire]]
  *[[http://corsair.wikidot.com/corsair-hiss|Corsair Hiss Discussion]]
  *[[http://pa0fri.home.xs4all.nl/Mods/Corsair/corsaireng.htm|PA0FRI Corsair Mod Page]]
===== Links =====
  *[[http://corsair.wikidot.com/|Corsair II Wiki]] - plenty of info and mods
===== Sales Information =====
{{561_brochure.pdf|Corsair II Brochure}} (4.48 MB)

The last Corsair II units were manufactured in Sept 1989


===== Specifications =====
==== General ====
    ***Frequency Coverage:** 1.8 - 2.3, 3.5 - 4.0, 7.0 - 7.5, 10.0 - 10.5, 14.0 - 14.5, 18.0 - 18.5, 21.0 - 21.5, 24.5 - 25.0, 28.0 - 30.0 MHz transceive. (VFO provides approximately 40 kHz overrun on each band edge.).
  ***VFO Stability:** Less than 15 Hz change per F<sup>o</sup> averaged over a 40<sup>o</sup> change from 70<sup>o</sup> to 110<sup>o</sup> F after 30 minutes warmup.  Less than 10 Hz change from 105 to 125 Vac line voltage when using a TEN-TEC power supply.
  ***Tuning Rate:** Vernier, 18 kHz per revolution, typical.
  ***Readout:** 6 digit, 0.3" LED numerals.
  ***Accuracy:** +/- 100 Hz.
  ***Semi-Conductors:** 1 LSI, 25 IC's, 94 transistors, 109 diodes, 6 LED readouts.
  ***PC Boards:** 22 PC assemblies with plug-in cables.
  ***Construction:** Rigid steel chassis.  Extruded aluminum front panel with two-tone gray inserts. Textured gray top and bottom.  Snap-up stainless steel bail.
  ***Power Required:** 12-14 Vdc, 850 mA receive, 18.5 A max transmit.
  ***Dimensions:** HWD 5.25" x 15" x 14"  (13 x 38 x 36 cm), bail retracted.
  ***Weight:** 14 lbs - 6.4 kg.

==== Receiver ====
  ***Sensitivity:** 0.25 uV for 10 dB S+N/N, all bands. 0.8 uV typical with RF amplifier off.
  ***Selectivity:** 16-pole crystal ladder filtering.  2.4 kHz bandwidth, 1.6 to 1 shape factor at 6/60 dB.  Three position switch selects standard ssb filter, optional 1.8 kHz ssb filter, 500 Hz cw filter, or 250 Hz cw filter.
  ***Notch Filter:** Greater than 50 dB notch tunable between 200 Hz and 3.5 kHz.
  ***Audio Bandpass Filter:** 8 pole active band pass centered at 750 Hz.  Variable fader control selects filtered for flat audio response.
  ***CW Spot:** Removes offset and shifts BFO 750 Hz.
  ***I-F Frequencies:** 9 MHz and 6.3 MHz.
  ***Antenna Input:** Low impedance, unbalanced.
  ***RX Antenna Input:** Switchable 50 ohm RCA phono jack provides separate input to receiver section only.
  ***Audio Output:** 1 watt @ 8 ohms with less than 2% distortion.  Built-in speaker.
  ***Spurious Responses:** All below equivalent 10 dB S+N/N signal except 1.838 MHz (less than 15 dB S+N/N), 21.300 MHz (less than 20 dB S+N/N), and 28.980 MHz (which can be eliminated by using low end of 29.0 - 29.5 MHz band segment).
  ***Noise Blanker:** Switchable on/off with adjustable threshold and blanking width.
  ***I-F Rejection:** Greater than 60 dB.
  ***S-Meter:** Automatically switched on when receiving.  Calibrated to 50uV at S9, +/- 3 dB.
  ***Dynamic Range:** 95 dB, typical.
  ***Offset Tuning:** Dual range, MAX +/- 4 kHz; MIN +/- 1.5 kHz, typical.
  ***Receiver Recovery Delay:** Less than 30 mS from key-up.

==== Transmitter ====
  ***DC Power Input:** Maximum 200 watts @ 14 Vdc cw and ssb.  100% duty cycle for up to 20 minutes.
  ***RF Output:** 85 - 100 watts, typical.
  ***Output Impedance:** 50 ohms, unbalanced.
  ***Microphone Impedance:** High impedance.  Accepts high or low impedance microphones with 5 mV output  Polarizing voltage available for electrets.
  ***T/R Switching:** VOX or PTT on ssb.  Instant break-in or semi-break-in on cw.
  ***CW Sidetone:** Internally generated.  Adjustable tone and volume independent of af gain control.  Operates only in cw mode.
  ***Programmable Iambic Keyer:** 8 - 50 wpm with 40 character memory.
  ***SSB Generation:** 9 MHz, 8-pole crystal ladder filter.  Balanced modulator.
  ***Carrier Suppression:** 60 dB typical.
  ***Unwanted Sideband Suppression:** 60 dB typical at 1.5 kHz tone.
  ***Spurious Output:** Better than -45 dB relative to full output.
  ***Meter:** Forward power, collector current, SWR, audio processing level.  Selectible 4 position switch.
  ***CW Offset:** 750 Hz, automatic
  ***ALC Control:** Front panel adjustable. 30 to 100 Watts output, LED indicator.