(a) The transmitting radiated power for stations authorized under the Experimental Radio Service shall be limited to the minimum practical radiated power necessary for the success of the experiment.

(b) For broadcast experimental radio stations, the operating power shall not exceed by more than 5 percent the maximum power specified. Engineering standards have not been established for these stations. The efficiency factor for the last radio stage of transmitters employed will be subject to individual determination but shall be in general agreement with values normally employed for similar equipment operated within the frequency range authorized.