Communication Helmet ISH4-U, jointly with equipment of integral connection and commutation ABCK R-174T, ABCK R-174, intercom system R-124 or their analogues is intended to provide communication in armored vehicles, protection of a radio operator both against the effect of external noise and climatic factors, and against impacts across construction members of the vehicle.
The communication helmet is essentially a headgear that covers all the head surface, except for a face, and has a high- level noise stability headset sewn in the helmet that consists of a cable to contact to the push-to-talk switch from the ABCK set of any type.
The communication helmet keeps its serviceability under:
- ambient temperature from minus 50° C to +50° C;
- relative air humidity up to 98% at temperature not less than + 25° C;
- vibratory load in a range of 10 to 80 Hz with acceleration 29.4 m/s2 (3g);
- impact load with acceleration 735 m/s2 (75g) with pulse duration from 0.5 to 2.0 ms;
- effect of acoustic noise up to 135 dB;
- cyclic temperature changes from minus 60° C to +70° C;
- effect of hoar-frost and dew;
- conditions of low atmospheric pressure (6x104 ± 4x103) Pa ((450 ± 30) mm Hg);
- after atmospheric pressure impact 2.3 x 10-4 Pa (170mm Hg) at ambient temperature 223 K (minus 50°C), appropriate to air transporting.
The helmet is produced in two versions:
- summer TSH4-UL;
- winter TSH4-UZ.
Each variant is made of three sizes (I, II, III). A number of the helmet size corresponds to a size of a human head.
|Helmet size number||Head size, sm|
Up to 56 inclusive
MAIN ELECTICAL SPECIFICATIONS
|Description of the main parameters ||Norm upon Specifications|
1. Verbal speech legibility under conditions of acoustic noise up to 135 dB, not less, %
2. Noise suppression factor at frequency 1000Hz, not less, dB
3. Total noise stability of throat microphone under conditions
4. Scalar impedance of a pair of throat microphone at frequency 1000 Hz, Ohm
5. Scalar impedance of a pair of telephones at frequency 1000 Hz, Ohm
6. Optimal level of voltage applied at headphones, V
7. Speech efficiency of throat microphones of the communication helmet, mV
Weight of communication helmet of a medium size must not exceed 1,1kg.