Purchasing Specifications

MH3 Tactical Headset System Purchasing Specification

A fully adjustable, ruggedized, submersible, low-profile two-way radio communications headset incorporating one or two (bone mass) vibrating transducers for receiving audio signals, and a nose canceling waterproof electret microphone mounted on a 5 inch flexible boom for transmitting audio signals. The transducers are to be integrated with housings that permit them to be worn over the temporal bones of the face, directly in front of the ears, with no speaker hardware required in, on or over either ear, in order to permit completely unobstructed natural hearing of ambient auditory sounds. The transducers are to work as a closed (bone mass) vibrating system, not requiring air as a conducting medium. The transducers are tuned specifically for response to the human voice band. The headset frame is to be constructed in a manner which permits adjustment of contact tension against the face and head; including adjustments for conformity to various facial shapes and conformity to various head sizes.

Top avoid conflict with helmets and helmet suspension systems, or other head gear including protective masks and eyewear, the transducer housings (headset sidepieces) shall be rigidly attached to a non-corrosive stainless steel headband that extends rearward in a fundamentally horizontal plane that encircles the back of the wearer’s head at the nape of the neck. The stainless steel headband shall be bendable at various points, and in various directions, to permit adjustment to the amount of contact tension against the individual wearer’s face, and to permit other adjustments which allow the entire headset to conform to the shape of the individual wearer’s face and head. The headset sidepieces and their attachment to the stainless steel headband must be constructed in a manner durable enough to withstand repeated multi-directional bending, including rotational torque, without sustaining damage. To permit horizontal size (or length) adjustment, the steel headband shall move in or out of the sidepieces by as much as ,625 inches, and will have no less than 3 incremental self-locking stops to adequately maintain the adjusted position.

To permit vertical adjustment, a .750 wide nylon web gear strap will pass over the top of the wearer’s head and shall be attached to the headset sidepieces with hook and loop fasteners permitting as much as 1 inch of adjustment on each end of the strap.

The headset sidepiece must be constructed from a plastic composite specially formulated to maximize signal response while minimizing spurious audio emissions. Further, the composite must withstand high impact and extreme temperature changes, and the external surface must be textured and colored to be non-reflective.

The headset sidepieces and stainless steel headband must be configured in a way to avoid interfering with the simultaneous use of vision correcting and or protective eyewear, and NBC and SCBA face masks/breathing apparatus.

To enable intelligible communications when the wearer is using a gas mask or SCBA, a breathing apparatus adapter kit (featuring custom components specifically designed for the various mask systems) which mechanically and acoustically couples the microphone to the voicemitter portion of the mask, will be available.

All metal hardware must be of stainless steel or treated to eliminate corrosion and allow use in saltwater conditions.

All cables and strain reliefs must be made of a material that will remain flexible in cold temperatures, and be resistant to petroleum based products and insect repellants.


Microphone:

Noise canceling electret

Frequency response: 150 hz to 5 KHz

Bias: 1.3V (1~20V)

Impedence: 3 KOhm

Current drain: 30 uA at 1.3V (10~60 uA)

Rs: 16KOhm nominal

Preamp Options:

02: Two Wire Connectors

R: 2.2 KOhm

Supply Voltage: 2 V

Current drain: 170 uA

Distortion (1% THD): 120 dB SPL

04: HIGH SPL “A” Model

Internal Rs omitted RX: 30 KOhm

Supply voltage: 12 V

Distortion (1% THD): 145 dB SPL

Current drain: 500 uA

Waterproof to 1 meter of water, including saltwater

Boom: 6.3mm (1/4 inch diameter); 5 inches long, black polyurethane covering

PTT:

Various styles available (See MH Series PTT Assemblies)

Submersible to 1 meter: including the “J”, “K” body worn assemblies and “SUB” finger/weapon mount style

Surface Water Applications: including the “L”, “M” and “R” body worn assemblies and “WR” finger/weapon mount style

Temperature range: -55C to +85C

Operating cycles: 30,000 to 100,000 depending upon style of PTT

Operating force: Average of 1.7+/-.5lbs

Snap action style

Transducers:

Operating temperature: Meets or exceeds operating temperature of all current popular transceivers

Input impedance: 10 ohms to 1200 ohms as required to match radio audio output, specifically tuned to response to the human voice

Receiver response: 250 to 4000Hz

Mechanical:

Transducer Housings (sidepieces):

Specific Gravity: ASTM D 792 tested – (1.37 Value)

Tensile Strength Break (psi) ASTM D tested 636 – (26.227 Value)

Tensile Elongation Break (%) ASTM D 638 tested – 4 Value)

Flexural Modulus (psi) ASTM D 790 tested – (1.287,000 Value)

Notched Izod Impact ASTM D 266 tested – (3.0 Value)

Unnotched Izod Impact ASTM D 4612 tested – (22.0 Value)

Heat Deflection ASTM D tested – (424 Value)

Sidepiece Cushions/Adhesive:

WS-1 SBT Synthetic Chloroprene / Black

Butadiene Rubber – 24 to 65%

Styrene Butadiene Rubber – 15 to 20%

Nature Rubber – 10 – 15%

Testing Procedures (including adhesive): PSTC-33, ASTM-D-1000, TAPPI-T-411 M-44, Fasson TM-2