MIL-STD-188-243 Tactical Single Channel Ultra High Frequency UHF Radio CommunicationsThe purpose of this document is to establish the minimum essential interoperability and performance requirements necessary for tactical single channel UHF radio communications equipment. This standard addresses ground-to-air, air-to-air, ship-to-shore and ship-to-ship tactical single channel UHF radio communications equipment. The requirements established by this document may be exceeded in order to satisfy specific operational requirements or to incorporate technological improvements, provided that interoperability be maintained.

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MIL-STD-188-243A

level (-40 dBm0) for wide band. In the ANI mode, measurements shall be taken with an RF input signal that produces 90 percent modulation at full rated audio output. Narrowband FM measurements shall be taken with an RF input signal that produces a peak deviation of 5 kHz at full rated audio output. Wideband FM measurements shall be taken with an RF input signal that produces a peak deviation of 20 kHz fit full rated audio output.

5.2.3.7.3 Internally Generated Spurious Signals. Not standardized.

NOTE: Spurious signals generated internally in the receiver in the absence of RF input signals, shall have sufficiently low levels to allow unrestricted tuning and reception of wanted signals in any channel. Detailed requirements shall be stated in the equipment specifications.

5.2.3.7.4 Hum and Noise Levels. The hum and noise levels measured at the receiver output shall be at least 40 dB below the reference level (-40 dJ3mO). The DO shall be -50 dBm0.

5.2.3.7.5 Spurious Response. The receiver response to spurious signals, including image response, shall be attenuated not less than 80 dB with respect to the received signal.

5.3 UHF Single Channel Survival Radio Equipment. The international survival frequency, 243.0

MHz, is within the military UHF frequency band. Such equipment includes a line-of-sight (LOS) antenna. The requirements contained in this document for single channel survival radio equipment have been based on, and are compatible with, the standards set forth by the ICAO.

5.3.1 Frequency. Survival radio equipment shall operate on the frequency of 243.0 MHz.

5.3.2 Frequency Tolerance. The frequency tolerance shall not exceed 0.005 percent.

5.3.3 Emission Requirements. The antenna emission shall be vertically polarized and omnidirectional in the horizontal plane.

5.3.4 Minimum Radiated Power. The radio's prime power source shall have the capability such that, over a 24-hour period of continuous operation, the mean radiated power shall at no time be less than 100 mW.

5.3.5 Emission Type. The type of emission shall be A2A. A3E shall be permitted in addition to

A2A.

5.3.6 Emission Interruption. The duration of interruption of the emission, if any, shall be such that it will not prejudice the detection and precise location of the survival radio by the homing equipment.

5.3.7 Modulation. The carrier shall be amplitude modulated by a factor of at least 85 percent.

5.3.8 Audio Characteristics. The emission shall have a distinctive audio characteristic achieved by modulating the carrier with a varying audio frequency. The audio frequency shall sweep downward from a higher frequency to a lower frequency. The higher frequency and the lower