§  15.709   General technical requirements.

   (a) Power limits for TVBDs are as follows: (1) For fixed TVBDs, the
   maximum conducted output power over the TV channel of operation shall
   not exceed one watt. Transmitter power will be measured at the antenna
   input to account for any cable losses between the transmitter and the
   antenna. If transmitting antennas of directional gain greater than 6
   dBi are used, the maximum conducted output power shall be reduced by
   the amount in dB that the directional gain of the antenna exceeds 6
   dBi.

   (2) For personal/portable TVBDs, the maximum conducted output power
   over the TV channel of operation shall not exceed 100 milliwatts;
   except that for personal/portable TVBDs that do not meet the adjacent
   channel separation requirements in § 15.712(a), the maximum conducted
   output power shall not exceed 40 milliwatts. If transmitting antennas
   of directional gain greater than 0 dBi are used, the maximum conducted
   output power shall be reduced by the amount in dB that the directional
   gain of the antenna exceeds 0 dBi.

   (3) TVBDs shall incorporate transmit power control to limit their
   operating power to the minimum necessary for successful communication.
   Applicants for certification shall include a description of a device's
   transmit power control feature mechanism.

   (4) Maximum conducted output power is the total transmit power in the
   entire emission bandwidth delivered to all antennas and antenna
   elements averaged across all symbols in the signaling alphabet when the
   transmitter is operating at its maximum power control level. Power must
   be summed across all antennas and antenna elements. The average must
   not include any time intervals during which the transmitter is off or
   is transmitting at a reduced power level. If multiple modes of
   operation are possible ( e.g. , alternative modulation methods), the
   maximum conducted output power is the highest total transmit power
   occurring in any mode.

   (b) Antenna requirements . (1) For personal/portable TVBDs, the antenna
   shall be permanently attached.

   (2) The receive antenna used with fixed devices shall be located
   outdoors at least 10 meters above the ground. The antenna system shall
   be capable of receiving signals of protected services equally in all
   directions. The transmit antenna used with fixed devices may not be
   more than 30 meters above the ground.

   (3) For both fixed and personal/portable TVBDs, the provisions of
   § 15.204(c)(4) do not apply to an antenna used for transmission and
   reception/spectrum sensing.

   (4) For both fixed and personal/portable TVBDs with a separate sensing
   antenna, compliance testing shall be performed using the lowest gain
   antenna for each type of antenna to be certified.

   (c) Undesirable emission limits for TVBDs are as follows:

   (1) In the 6 MHz channels adjacent to the operating channel, emissions
   from TVBD devices shall be at least 55 dB below the highest average
   power in the band in which the device is operating.

   (2) The above emission measurements shall be performed using a minimum
   resolution bandwidth of 100 kHz with an average detector. A narrower
   resolution bandwidth may be employed near the band edge, when
   necessary, provided the measured energy is integrated to show the total
   power over 100 kHz.

   (3) At frequencies beyond 6 MHz from the edge of the operating channel,
   radiated emissions from TVBD devices shall meet the requirements of
   § 15.209.

   (4) Emissions in the band 602-620 MHz must also comply with the
   following field strength limits at a distance of one meter.
   Frequency
   (MHz) Field strength
   dBuV/meter/120 kHz
         602-607       120-5[F(MHz)-602]
         607-608       95
         608-614       30
         614-615       95
         615-620       120-5[620-F(MHz)]

   (5) TVBDs connected to the AC power line are required to comply with
   the conducted limits set forth in § 15.207.

   (d) Compliance with radio frequency exposure requirements. To ensure
   compliance with the Commission's radio frequency exposure requirements
   in § § 1.1307(b), 2.1091 and 2.1093 of this chapter, fixed TVBDs shall
   be accompanied by instructions on measures to take to ensure that
   persons maintain a distance of at least 40 cm from the device, as well
   as any necessary hardware that may be needed to implement that
   protection. These instructions shall be submitted with the application
   for certification. Personal/portable TVBDs that meet the definition of
   portable devices under § 2.1093 of this chapter and that operate with a
   source-based time-averaged output of less than 20 mW will not be
   subject to routine evaluation for compliance with the radio frequency
   exposure guidelines, while devices that operate with a source-based
   time-average output power greater than 20 mW will be subject to the
   routine evaluation requirements.