The Countermeasures Amplifier (CMA-100) is a high gain audio amplifier used to detect and identify certain types of surveillance devices attached to building wiring such as telephone wiring, LAN and server systems, AC Power, Alarm wire etc. The CMA-100 is designed to provide flexable features and will prove to be very useful in many situations.

The CMA-100 has a balanced input impedance of 50K ohm, can withstand being attached to live power lines with voltages up to 250V, and provides up to 115dB of gain. Additionally, the CMA-100 utilizes a unique AGC that can automatically adjust gain from -20 to 120dB. Signals as large as 10V peak-peak can still be monitored with minimal distortions. Manual gain control can be set to 0, 25, 50, 75, or 100dB. Filters can be positioned to FLAT, LOW PASS, HIGH PASS, or BAND PASS.

CMA-100 Advantages
This multifunctional amplifier has a built in AC/DC digital voltmeter, selectable audio filters, and an extremely wide dynamic range. Balanced and Unbalanced high impedance inputs provide connectivity to a variety of suspect wiring. The CMA-100 also provides a bias voltage adjustable between -15V and +15V DC that is used to activate possible devices that are voltage or current sensitive. The bias generator is compatible with most types of line conditions. All of these functions employ a sophisticated automatic gain control circuit that is superior to most audio amplifiers.

General Specification:

  • Input Impedance: 50k balanced
  • Common Mode Rejection: >75dB
  • Maximum Usable Input: 10V p-p
  • Preamp Auto attenuator: 0 to -20 dB ( with overload warning LED )
  • Automatic Gain Control: -20 to +120 dB ( includes preamp auto attenuator )
  • Manual Gain Control: 0, 25, 50, 75, 100 dB
  • Headphone Gain Control: 0 to 15 dB
  • Maximum System Gain: 115 dB manual mode, 120 dB in Auto Mode
  • Frequency Response: 100 Hz to 15Khz
  • High Pass Filter: 300Hz to 20kHz
  • Low Pass Filter: 100Hz to 3kHz
  • Band Pass Filter: 300Hz to 3kHz
  • Headphone Audio Output
  • Line-Out Audio Output: 600
  • Bias Control: 0 to +/-15V DC, 5mA max ( over current protected, input impedance is reduced to 3k ohms when bias is active )
  • Digital Voltmeter: 3.5 Digit, auto zero, auto polarity, +/-199.9V AC/DC
  • Power On/Low Battery LED ( LED off @ 6.0V )
  • Battery: 9V Alkaline ( 4-7 Hrs typical run time )
  • Maximum Input voltage: 250V AC/DC
  • Leakage Resistance to Case: >10M
  • Size: 7.3″(184.4mm) x 2.75″(69.8mm) x 1.75″(44.5mm)
  • Weight: 12.1 oz (343g)

Some specifications subject to change.