The Communication Helmet consists of the following parts:
- helmet which represents a headwear covering the entire head surface excepting for face;
- headset with a microphone with high level of protection against noises built in the helmet and consisted of two headphones connected serially and two throat microphones;
- cable to be connected to breast switch included in intercom and switching equipment of any type.
The Communication Helmet is manufactured in two versions: summer version and winter version.
Either version is manufactured in three sizes (І, ІІ, ІІІ). The helmet size number corresponds to human head dimensions.
The Communication Helmet weight is 1.1 kg, max.
The Communication Helmet remains serviceable:
- at an ambient temperature range from minus 50 ˚С to + 50 ˚С;
- at a relative ambient air humidity not higher than 98% at the temperature of +25˚С;
- under vibration loads within the range of 10-80 Hz at the acceleration of 29,4m/sec2 (3g);
- under impact loads with acceleration of 735 m/sec2 (75g) with pulse durability from 0,5 to 2,0 msec;
- under the exposure to acoustic noises up to 135 dB;
- under the cycle changes in temperatures from minus 60˚С to + 70˚С;
- under the exposure to hoar-frost and dew;
- under the conditions of lower atmosphere pressure (6х104 ± 4х103 ) Pa ((450 ± 30) mm of mercury column).
|Basic parameter denomination||Norm in accordancewith technical|
|Speech intelligibility under acoustic noise conditions up to 135 dB, %, min.||90|
|Noise suppression factor at the frequency of частоте 1000 Hz, dB, min.||13|
|Throat Microphones’ total resistance to noise under acoustic noise conditions up to 135 dB, min.||16|
|Electrical resistance modulus of a pair of Throat Microphones at the frequency of 1000 Hz, Ohms||80±16|
|Electrical resistance modulus of a pair of telephones at the frequency of 1000 Hz, Ohms||520±104|
|Optimal level of voltage supplied to the telephones, V||5 – 8|
|Speech Efficiency of the communication helmet throat microphones, mV||0,5 – 0,8|