Sec. 87.23  Supplemental information required.

    (a) To minimize harmful interference at the National Radio Astronomy 
Observatory site at Green Bank, Pocahontas County, WV, and at the Naval 
Radio Research Observatory site at Sugar Grove, Pendleton County, WV, an 
applicant for a new station license (other than mobile, temporary base, 
temporary fixed or Civil Air Patrol), or for modification of an existing 
license to change the frequency, power, antenna location, height or 
directivity within the area bounded by 39'15' N. on the north, 78'30' W. 
on the east, 37'30' N on the south and 80'30' W on the west, must first 
notify the Director, National Radio Astronomy Observatory, Attn: 
Interference Office, Post Office Box No. 2, Green Bank, WV 24944, in 
writing, of the geographical coordinates of the antenna, antenna height, 
antenna directivity, frequency, emission and power. The application to 
the Commission must show the date notification was made to the 
Observatory. The Commission will allow twenty (20) days after receipt of 
its copy of the notification for comments or objections. If a timely 
response is received, the Commission will consider the comments or 
objections.

[[Page 194]]

    (b) Geographical coordinates of Commission facilities which require 
protection are listed in Sec. 0.121(c). Applications for stations 
(except mobile stations) which will be located within 80 km (50 miles) 
of the referenced coordinates are examined to determine extent of 
possible interference. A clause protecting the monitoring station may be 
added to the station license.
    (c) Each application for a station license to operate in the 
vicinity of Boulder County, CO, under this part must give due 
consideration, prior to filing applications, to the need to protect the 
Table Mountain Radio Receiving Zone from harmful interference. These are 
the Research Laboratories of the Department of Commerce, Boulder County, 
CO. To prevent degradation of the present ambient radio signal level at 
the site, the Department of Commerce seeks to ensure that field strength 
at 40 deg.07'50' N latitude, 105 deg. 14'40' W longitude, resulting from 
new assignments (other than mobile stations) or from the modification or 
relocation of the existing facilities do not exceed the following 
values:

------------------------------------------------------------------------
                                                            Power flux  
                                          Field strength    density \1\ 
                                             (mV/m) in    (dBW/m \2\) in
             Frequency range                authorized      authorized  
                                           bandwidth of    bandwidth of 
                                              service         service   
------------------------------------------------------------------------
Below 540 kHz...........................              10           -65.8
540 to 1600 kHz.........................              20           -59.8
1.6 to 470 MHz..........................              10        \2\-65.8
470 to 890 MHz..........................              30        \2\-56.2
Above 890 MHz...........................               1        \2\-85.8
------------------------------------------------------------------------
\1\ Equivalent values of power flux density are calculated assuming a   
  free-space characteristic impedence of 376.7 (approximately 120 pi)   
  ohms.                                                                 
\2\ Space stations shall conform to the power flux density limits at the
  earth's surface specified in appropriate parts of the Commission's    
  rules, but in no case should exceed the above levels in any 4 kHz band
  for all angles of arrival.                                            

    (d) Each applicant is responsible for determining whether proposals 
for a new or modified station require envionmental information. 
Applicants should refer to Sec. 1.1307 to identify those actions for 
which environmental information must be submitted.
[ 53 FR 28940 , Aug. 1, 1988, as amended at  54 FR 11719 , Mar. 22, 1989]