Sec. 101.143  Minimum path length requirements.

    (a) The distance between end points of a fixed link in the private 
operational fixed point-to-point and the common carrier fixed point-to-
point microwave services must equal or exceed the value set forth in the 
table below or the EIRP must be reduced in accordance with the equation 
set forth below:

                                                                        
------------------------------------------------------------------------
                                                               Minimum  
                    Frequency band (MHz)                     path length
                                                                 (km)   
------------------------------------------------------------------------
Below 1,850................................................          N/A
1,850 to 7,125.............................................           17
10,550 to 13,250...........................................            5
Above 17,700...............................................          N/A
------------------------------------------------------------------------

    (b) For paths shorter than those specified in the Table, the EIRP 
shall not exceed the value derived from the following equation:

EIRP = MAX EIRP--40*log(A/B) dBW

Where:
EIRP = Equivalent isotropically radiated power in dBW.
A = Minimum path length from the Table for the frequency band in 
kilometers.
B = The actual path length in kilometers.

    Note to paragraph (b): For transmitters using Automatic Transmit 
Power Control, EIRP that corresponds to the maximum transmitter power 
must satisfy this requirement.

    (c) Upon an appropriate technical showing, applicants and licensees 
unable to meet the minimum path length requirement may be granted an 
exception to these requirements.

    Note to paragraph (c): Links authorized prior to April 1, 1987, need 
not comply with this requirement.