§  101.131   Transmitter construction and installation.

   (a) The equipment at the operating and transmitting positions must be
   so installed and protected that it is not accessible to, or capable of
   being operated by, persons other than those duly authorized by the
   licensee.

   (b) In any case where the maximum modulating frequency of a transmitter
   is prescribed by the Commission, the transmitter must be equipped with
   a low-pass or band-pass modulation filter of suitable performance
   characteristics. In those cases where a modulation limiter is employed,
   the modulation filter must be installed between the transmitter stage
   in which limiting is effected and the modulated stage of the
   transmitter.

   (c) Each transmitter employed in these services must be equipped with
   an appropriately labeled pilot lamp or meter which will provide
   continuous visual indication at the transmitter when its control
   circuits have been placed in a condition to activate the transmitter.
   In addition, facilities must be provided at each transmitter to permit
   the transmitter to be turned on and off independently of any remote
   control circuits associated therewith.

   (d) At each transmitter control point the following facilities must be
   installed:

   (1) A carrier operated device which will provide continuous visual
   indication when the transmitter is radiating, or, in lieu thereof, a
   pilot lamp or meter which will provide continuous visual indication
   when the transmitter control circuits have been placed in a condition
   to activate the transmitter; and

   (2) Facilities which will permit the operator to turn transmitter
   carrier on and off at will.

   (e) Transmitter control circuits from any control point must be so
   installed that grounding or shorting any line in the control circuit
   will not cause the transmitter to radiate: provided, however, That this
   provision will not be applicable to control circuits of stations which
   normally operate with continuous radiation or to control circuits which
   are under the effective operational control of responsible operating
   personnel 24 hours per day.