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Mohawk ← 300
Portable tape cartridge audio recorder
- this page is a stub
Midgetape Chief 400 is a portable transistorised
audio tape cartridge recorder,
introduced in 1958 by Mohawk Business Machines in New York (USA)
as the successor to the Midgetape 300.
Although initially intended as a dictation machine, it was also used in
surveillance as it could easily be hidden on the body. This was further promoted
by the availability of a wristwatch microphone and a shoulder holster.
It is known that these devices were used by the CIA.
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The device measures 220 × 100 × 55 mm and weights 1.2 kg without batteries.
It was supplied in a leather case that could be carried from the shoulder.
For covert recordings it was usually carried in a special cloth shoulder holster,
that could easily be hidden under the clothing.
Audio frequencies between 150 and 5,000 Hz are recorded onto a 6.35 mm wide
double-sided magnetic tape with a Mylar base, at a speed of 4.76 cm/s.
The maximum recording time was 45 minutes per side, far less than
contemporary Protona wire recorders like the
Minifon P-55.
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The latter had a recording time of sevaral hours.
Mohawk tape recorders can be seen as the American competitor
of the contemporary German Minifon wire recorders that were also
used by the CIA. Mohawk was earlier to migrate to magnetic tape than
competitor Protona,
but – like all tape recorders – missed the extended recording time.
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Device Miniature audio recorder Purpose Dictation, covert recording Model Midgetape Chief 400 Manufacturer Mohawk Business Machines Year 1958 Predecessor Midgetape 300 Successor Midgetape Professional 500 Medium Tape, Dupont Mylar base Width 6.35 mm (1/4 in) Speed 4.76 cm/s (1 7/8 in/s) Cartridge 45 min/side Input ≥ 1 mV, 2000Ω Output 10 mW into 2000Ω Response 150 - 5000 Hz W&F < 0.7% S/N 42dB Bias 20 kHz Transistors 4 Dimensions 220 x 100 x 55 mm Weight 1.2 kg Price US$ 269.50 (1958)
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- 1 x GT81
- 1 x GT-82
- 2 x 2N406
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401 Leather carrying case 402 Internal Power Amplifier with built-in speaker 403 Mains power supply unit (for 110V AC only) 404 Transcribing Control [5] 405 Cowhide briefcase concealment (with hidden microphone) 406 Same as 405, but without hidden microphone 407 Telephone pick-up coil 408 Wristwatch microphone 409 Concealable lapel microphone 410 Throat microphone 411 Standard microphone/speaker with clip stand 412 Shoulder holster 420 Car battery converter (12V) 421 Stethoscope-style earphones 422 Combined speaker/microphone with PTT RL-60 Tape cartridge 2 x 30 min. RL-90 Tape cartridge 2 x 45 min. T-12 Motor battery (12-15 hours) T-50 Motor battery (50+ hours)
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© Crypto Museum. Created: Thursday 09 June 2022. Last changed: Monday, 12 February 2024 - 15:33 CET.
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