A-A-50603 Loudspeaker - Microphone (Megaphone, Electronic, Portable)This Commercial Item Description covers requirements for a hand held electronic megaphone, which is rugged, lightweight, portable, and amplifies audio frequencies for transmitting intelligible speech over distance in excess of 200 meters through high ambient noise levels (85 db). This description covers commercial off-the-shelf megaphone equipment with minor modifications essential to adapt equipment for Military use.

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A-A-50603

2.1 Moisture proofing. All electronic components shall be conformal coated to ensure operability in a moisture laden environment.

2.2 Splash proofing. Microphones and speaker horns shall be constructed of materials that are unaffected when splashed with water.

2.3 Preservation. All parts shall be of suitable corrosion resistance material or materials treated in a satisfactory manor to render them adequately resistant to corrosion caused by sea water.

3. Weight and size. The maximum weight of the megaphone including the battery compartment shall be 1.5 kilograms without batteries, the maximum length shall not exceed 350 millimeters and the maximum horn diameter shall not exceed 200 millimeters.

4. Microphone. The microphone shall be an anti-howling, 600 ohm, 1 millivolt, dynamic type microphone mounted in the main body of the megaphone.

5. Horn assembly. The horn assembly shall consist of a horn unit, voice coil, diaphragm assembly and annular plug (if required).

6. Power Output. Megaphones shall operate at a rated output power of at least 10 watts or greater when measured with a 1000 Hertz, 1 millivolt input signal.

7. Power consumption. Megaphone power consumption shall be in accordance with the guidance listed below.

8. Power Sources. Megaphones shall be powered from dry cell batteries.

9. Equipment Operating Time. The equipment shall operate in excess of five (5) hours voice and thirty (30) minutes siren without requiring a battery change.