Corsair II Model 561

• 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 Errata
• Corsair II Noise Blanker Schematic

• Corsair Audio Mods
• Broadcast Interference Fix
• Relay Noise Mod
• Intermittent LED Fix
• Audio Filter
• Knob Insert Replacements
• Knob Repair
• Display Problem & Fix
• Freq Drift - Offset Pot
• Weak Receive on Higher Bands - LPF TR Board
• QSK Mod (Contributed by AB9M)
• Socketing the 9Mhz Filter
• Balanced Modulator direct drive
• Detachable speaker wire
• Corsair Hiss Discussion
• PA0FRI Corsair Mod Page

• Corsair II Wiki - plenty of info and mods

Corsair II Brochure (4.48 MB)

The last Corsair II units were manufactured in Sept 1989

• 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^o averaged over a 40^o change from 70^o to 110^o 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.

• 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.

• 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.