§  90.215   Transmitter measurements.

   (a) The licensee of each station shall employ a suitable procedure to
   determine that the carrier frequency of each transmitter authorized to
   operate with an output power in excess of two watts is maintained
   within the tolerence prescribed in § 90.213. This determination shall
   be made, and the results entered in the station records in accordance
   with the following:

   (1) When the transmitter is initially installed;

   (2) When any change is made in the transmitter which may affect the
   carrier frequency or its stability.

   (b) The licensee of each station shall employ a suitable procedure to
   determine that each transmitter authorized to operate with an output
   power in excess of two watts does not exceed the maximum figure
   specified on the current station authorization. On authorizations
   stating only the input power to the final radiofrequency stage, the
   maximum permissible output power is 75 percent for frequencies below 25
   MHz and 60 percent of the input power for frequencies above 25 MHz. If
   a non-DC final radiofrequency stage is utilized, then the output power
   shall not exceed 75 percent of the input power. This determination
   shall be made, and the results thereof entered into the station
   records, in accordance with the following:

   (1) When the transmitter is initially installed;

   (2) When any change is made in the transmitter which may increase the
   transmitter power input.

   (c) The licensee of each station shall employ a suitable procedure to
   determine that the modulation of each transmitter, which is authorized
   to operate with an output power in excess of two watts, does not exceed
   the limits specified in this part. This determination shall be made and
   the following results entered in the station records, in accordance
   with the following:

   (1) When the transmitter is initially installed;

   (2) When any change is made in the transmitter which may affect the
   modulation characteristics.

   (d) The determinations required by paragraphs (a), (b), and (c) of this
   section may, at the opinion of the licensee, be made by a qualified
   engineering measurement service, in which case the required record
   entries shall show the name and address of the engineering measurement
   service as well as the name of the person making the measurements.

   (e) In the case of mobile transmitters, the determinations required by
   paragraphs (a) and (c) of this section may be made at a test or service
   bench: Provided, That the measurements are made under load conditions
   equivalent to actual operating conditions; and provided further, that
   after installation in the mobile unit the transmitter is given a
   routine check to determine that it is capable of being received
   satisfactorly by an appropriate receiver.