Description
International Microwave ACP3959-20CB Tunnel Diode Amplifier S-Band 2.7-4.2 GHz
The International Microwave ACP3959-20CB is a tunnel diode amplifier covering the S-band / low C-band frequency range from 2.7 to 4.2 GHz. Tunnel diode amplifiers are among the earliest solid-state microwave low-noise amplifiers, exploiting the negative-resistance characteristic of the tunnel (Esaki) diode to achieve useful gain with extremely low noise figures — properties that made them a preferred front-end amplifier in satellite ground station receivers, radar receivers, and sensitive microwave receivers during the 1960s through 1980s. This unit was manufactured by International Microwave Corp. (IMC) of Cos Cob, Connecticut, a company that produced specialized microwave components and subsystems for defense and communications applications.
Specifications & What's Included
- Manufacturer: International Microwave Corp. (IMC), Cos Cob, Connecticut
- Model: ACP3959-20CB
- Type: Tunnel Diode Amplifier
- Frequency Range: 2.7–4.2 GHz (S-Band / Low C-Band)
- Gain: 9.5 dB (±1.5 dB) — per handwritten calibration data on unit dated 6/1/85
- Noise Figure: 5.2 dB — per handwritten calibration data on unit
- Supply Voltage: +5 to 30V DC (per front-panel yellow label)
- Current Draw: 15 mA (per front-panel label)
- Battery Operation: 2 AA batteries (noted on unit)
- Input Connector: Coaxial (labeled INPUT on bottom panel)
- Output Connector: Coaxial (labeled OUTPUT on bottom panel)
- Power Connector: Circular multi-pin connector (MIL-spec style, side panel)
- ON/OFF toggle switch on front panel
- Warning label: Remove battery before applying external power
- Enclosure: Sealed gray metal box
- Country of Manufacture: United States
- Unit only — no external power supply, cables, or mounting hardware included
Applications
Tunnel diode amplifiers operating in the 2.7–4.2 GHz range were used as low-noise preamplifiers in S-band and low C-band receiving systems, including satellite ground station receivers (particularly early commercial and military SATCOM receivers), S-band radar receivers, and microwave link receivers. The S/C-band overlap of this unit's frequency range covers frequencies used in early INTELSAT and military satellite downlinks, as well as weather radar and air traffic control radar receivers. International Microwave Corp. supplied amplifiers and subsystems to government, defense, and communications programs during the Cold War era. Tunnel diode amplifiers of this type were eventually succeeded by GaAs FET and HEMT low-noise amplifiers in the 1980s and 1990s, but they remain collectible and functional components for vintage microwave system restoration, research, and laboratory use. The handwritten performance data on this unit, dated June 1985, suggests it was calibrated and in active use within a professional RF system at that time.
This International Microwave ACP3959-20CB Tunnel Diode Amplifier has been pulled from a working environment where it was previously in use. The unit has not been powered up or tested at our facility. The gray metal enclosure shows age-appropriate wear including surface scuffs, scratches, and soiling on the exterior panels. The INPUT and OUTPUT coax connectors and the circular power connector appear intact. Handwritten performance notes are present on the bottom panel, dated 6/1/85, indicating measured gain of 9.5 dB (±1.5 dB) over 2.7–4.2 GHz and a noise figure of 5.2 dB — these appear to be historical test data recorded at the time of calibration and are not a guarantee of current performance. Please view our photo set and contact us if you have any questions.
Warranty Information
Additional Information
Brand: |
International Microwave Corp |
Model: |
ACP3959-20CB |
MPN: |
ACP3959-20CB |
Type: |
Tunnel Diode Amplifier |
SKU: |
50425 |
Frequency Range: |
2.7–4.2 GHz |
Gain: |
9.5 dB (±1.5 dB) |
Noise Figure: |
5.2 dB |
Power Supply Voltage: |
+5 to 30V DC |
Current Draw: |
15 mA |
Battery Option: |
2 AA batteries |
Input Connector: |
Coaxial (INPUT labeled) |
Output Connector: |
Coaxial (OUTPUT labeled) |
Power Connector: |
Circular multi-pin (MIL-spec style) |
Band: |
S-Band / Low C-Band |
Form Factor: |
Enclosed Metal Box |
Country/Region of Manufacture: |
United States |
Seller Notes: |
Unit only — no external power supply or cables included. |
Condition Notes: |
This International Microwave ACP3959-20CB Tunnel Diode Amplifier was pulled from a working environment. Not powered or tested at our facility. Enclosure shows age-appropriate wear. Connectors appear intact. Sold as-is. |
California Prop 65 Warning: |
WARNING: This product can expose you to chemicals including lead and lead compounds, and DEHP (a phthalate), which are known to the State of California to cause cancer and birth defects or other reproductive harm. Go to P65Warnings.ca.gov |