§ 80.253 - Technical requirements for main transmitter.

Link to an amendment published at 68 FR 46966, Aug. 7, 2003.

(a) The following table gives the operating carrier frequency, emission, modulation and average ship station antenna power requirements for the main transmitter.

Operating frequency (kHz)Frequency toleranceParts 1 in 10 6Hz 2Class of emissionPercentage modulation for amplitude modulationModulation frequency for amplitude modulationPower into average ship station antenna500 kHz1,00020A2A and A2B or H2A and H2BNot less than 70; not more than 100At least 1 frequency between 300 and 1250 Hertz, except for transmittal installed after July 1, 1951, at least 1 frequency between 450 and 1250 HertzNot less than 200 watts.Do1,00020A1A or J2ANot less than 160 watts.410 and 2 working frequencies in the band 415 to 5251,00020A2A and A3N or H2A and H3NNot less than 70; not more than 100At least 1 frequency between 300 and 1250 Hertz, except for transmitters installed after July 1, 1951, at least 1 frequency between 450 and 1250 HertzNot less than 200 watts.Do1,00020A1A and N0N or J2A and J3NNot less than 160 watts.1 For equipment approved before November 30, 1977.2 For equipment approved after November 29, 1977.

(b) A main transmitter must operate at its required antenna power when adjusted to any required operating frequency and energized by the main power supply of the ship station or by an equivalent power supply.

(c) A main transmitter must be equipped to measure (1) antenna current, (2) transmitter power supply voltages, and (3) anode or collector current(s).

(d) The antenna power must be determined at the operating carrier frequency by the product of the antenna resistance and the square of the average antenna current, both measured at the same point in the antenna circuit at approximately ground potential.

(e) A main transmitter producing more than 250 watts output power must have the output power reduced to not more than 150 watts when used for telegraphy. In stations where a separate telegraph transmitter operable on the same frequencies as the main transmitter with an output power of less than 250 watts, is installed, the power reduction requirement does not apply. Such separate transmitters must not obtain power from the emergency power supply.

Effective Date Note:

At 68 FR 46966, Aug. 7, 2003, § 80.253 was removed effective October 6, 2003.