Sec. 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 Sec. 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

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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.