Section 15.229 - Operation within the band 40.66-40.70 MHz(a) Unless operating pursuant to the provisions in § 15.231 , the field strength of any emissions within this band shall not exceed 1,000 microvolts/meter at 3 meters.(b) As an alternative to the limit in paragraph (a) of this section, perimeter protection systems may demonstrate compliance with the following: the field strength of any emissions within this band shall not exceed 500 microvolts/meter at 3 meters, as determined using measurement instrumentations employing an average detector. The provisions in § 15.35 for limiting peak emissions apply where compliance of these devices is demonstrated under this alternative emission limit.(c) The field strength of any emissions appearing outside of this band shall not exceed the general radiated emission limits in § 15.209 .(d) The frequency tolerance of the carrier signal shall be maintained within ±0.01% of the operating frequency over a temperature variation of -20 degrees to + 50 degrees C at normal supply voltage, and for a variation in the primary supply voltage from 85% to 115% of the rated supply voltage at a temperature of 20 degrees C. For battery operated equipment, the equipment tests shall be performed using a new battery.54 FR 17714, Apr. 25, 1989, as amended at 55 FR 33910, Aug. 20, 1990