73.807 Minimum distance separation between stations

Pending Petition for Reconsideration

A Petition for Reconsideration has been filed by Todd Urick, et al on the Report and Order in MB Docket 19-193. This rule may be impacted by the outcome of the petition.

Protecting other domestic stations

LPFM stations use a simplified "distance separation" method in order to protect other stations. Since distances are rounded to the nearest kilometer, the actual distance separation is 0.5 km less than the values shown. For example, if the minimum distance separation is 67 km, an LPFM station located at 66.504 km would be acceptable.

For domestic full-service and Class D stations in the United States (including Alaska, Hawaii and the territories), other stations need to be protected on the co-channel (same), first-adjacent channel (+/- 0.2 MHz) and second-adjaent channel (+/- 0.4 MHz). LPFM stations are not required to protect third-adjacent channels (+/- 0.6 MHz), but references are still made for third-adjacent channels because of other rules, such as the continuing restriction on third-adjacent short-spacing where the primary station has a radio reading service for the blind.

These distances are based on the maximum facility for each service class based on a flat earth with no terrain. For co- and first-adjacent channels, the FCC includes two distances. The lower distance is the absolute minimum distance separation required by an LPFM station to the other class of station. The higher distance is the distance from the interfering contour of the incumbent station class to the service contour of the LPFM station. If the distance is between the lower and higher amounts, there is a higher possibility that an LPFM station would receive interference from the existing station.

Some Class B and C stations operate at parameters higher than their class maximums. These pre-1962 grandparented stations may continue to operate these higher powers. For commercial stations, the LPFM stations will still use the distance separations. Keep in mind that even though the LPFM meets minimum distance separation, the grandparented station may still cause interference. If the short-spaced station is a full-service or Class D station on 88.1~91.9, then the station is protected at a higher class based on the size of the service contour.

For LPFM stations in Puerto Rico and the U.S. Virgin Islands, the distance separation requirements to full-service stations are different because of the different definition of the service contour sizes for those stations.

LPFM stations are also required to protect the co-, first- and second-adjacent channels of FM translators. LPFM stations are not required to protect FM boosters (because boosters are required to keep their service contours inside of the service contours of the primary stations that they are operated for).

Second-adjacent channel waivers

Demonstrating compliance

LPFM stations may request a waiver of the second-adjacent channel minimum distance separation requirements in respect to domestic full-service stations, domestic class-D stations and FM translators. In order to demonstrate this, it has to be demonstrated that the actual interfering contour, which is based on 40 dB less than the field strength of the short-spaced station, does not reach any occupied structures or major 4 lane highways.

Using the contours calculated above, it can also be shown that, if based on the elevation pattern of the proposed antenna, that the pattern generates an interfering contour that does not penetrate any occupied area of any structure or major highway.

There have been past cases where Longley/Rice was used instead of contours to determine the field strength of the short-spaced second-adjacent channel station to be used in connection with the two methods already explained.

It can be shown by demonstrating that the 100 dBu (97/94 dBu) interfering contour of the LPFM proposal does not actually overlap the 60 dBu (57/54 dBu) protected contour of the short-spaced station.

There is no leeway for population in the "overlap zone". The Commission has determined that can't be waived because of the "any radio service" provision in the Local Community Radio Act.

Complaints by short spaced stations

When you are granted a waiver, you are expected to construct in the manner that is on your permit. Unless the license has specific conditions (or is directional), then you may construct with any antnenna other than the one used in the exhibit to demonstrate compliance. If a different antenna is installed, the LPFM runs the risk of a complaint by the short-spaced station.

The short-spaced station can make an interference complaint, even if it is years later. Once an LPFM is notified by the FCC that they are interfering, the LPFM station must immediately shut down. The LPFM station is unable to go back on the air until the interference is eliminated or it can demonstrate to the FCC that the interference was not caused by the LPFM station. While suspended, the LPFM station may engage in short test transmissions to check to assure that changes made did cure any interference problems.

International protections

LPFM stations that are near the Canadian and Mexican borders must protect foreign stations and vacant allotments. Those protections must be made on co-, first- and second- as well as third-adjacent channels. Canada has different values for the third-adjacent than the second-adjacent channels. LPFM stations very close to the border also have to protect the "intermediate frequencies" of foreign stations. I.F. channels are +/- 10.6 and 10.8 MHz (53 or 54 channels).

LPFM stations in Puerto Rico and especially in the Virgin Islands will have their information sent to the International Telecommunications Union for reporting to other Caribbean nations, especially the British Virgin Islands. There is no specific spacing rule to the BVI and not all BVI stations appear in the FCC databases. If another country (like the BVI) objects to a new station on technical grounds, the FCC can rescind the LPFM authorization.

LPFM stations that are within 125 km of Mexico will be authorized with up to 50 watts ERP (based on HAAT). If the LPFM proposes a directional antenna, they could be able to operate up to 100 watts in all directions, except those that are within 125 km of Mexico. These stations are also limited to a 60 dBu contour of 8.7 kilometers and a 34 dBu interfering contour of no more than 32 km in the directions that are within 125 km of Mexico. Stations more than 125 km of Mexico but within 320 km may operate up to 100 watts but no part of a 60 dBu contour can lie within 116.3 km of the Mexican border.

LPFM stations within 320 km of Mexico may not have a 34 dBu interfering contour that exceeds 60 km in any direction.

Original Report and Order (01/27/2000) para. 7-14, para. 60-104, para. 115,

MO&O on Reconsideration (09/22/2000) para. 5-26, para. 37-44, para. 51-57, para. 69-71,

Second Report and Order (03/22/2001 para. 2-4, para. 8-9

Fifth Report and Order (03/19/2012) para. 10-14

Sixth Report and Order (11/30/2012) para. 72-85, para. 90, para. 201-210

19-193: Report and Order (04/22/2020) para. 4-12

When the FCC created LPFM, the decision was made early on to use distance separation as opposed to using contours. Much of the reason for this could be attributed to statements made FCC Chairman (at the time) William Kennard who had a desire to keep LPFM so simple, "you would not have to hire a consulting engineer." This was also at a time when the FCC was converting from the old BAPS engineering database to the then-modern CDBS database. I really don't think staff was ready to "test" the directional antenna functionality to the extent that a LPFM filing window could bring. The FCC claimed in the Report and Order that using contours would be burdensome on the applicants.  The spacing was also written with a 20 kilometer buffer zone around the standard service contours of the full-service station classes.  This was intended to allow full-service FM stations to move by not putting much of a burden on the LPFM station.

You may also notice a "full-spaced" value for each full-service and FM translator class. This was a part of the "keep it simple" policy for LPFM at the time. These "fully-spaced" values are not binding but are provided only as a convenience.

When LPFM was originally created, there was both a 100-watt and a 10-watt service. The FCC would open a window for 100-watt stations and would delay the 10-watt service for a future time. At the time, the LP-10 rules were written so they would not be protected by LP-100 stations nor were they protected by transalators.  The wording of the Local Community Radio Act would have required LP-10 stations to be protected by translators.  The FCC never authorized any LP-10 stations and the service was eliminated in the November, 2012 Order.

The Radio Broadcast Protection Act would put the requirement of prescribe protections using distance separation from LPFM to all radio services on co-, first-, second and third-adjacent channels into statute in 2001.  When the Local Community Radio Act of 2010 was enacted in January 2011, there was a language change that was not really noticed until later in time. Under the LCRA, Section 2 requires the FCC to "prescribe protections" on co-channel, first and second adjacent channels. Section 2 did not elaborate what kind of protections, as opposed to the original RBPA language. Section 3 of the LCRA does state that the FCC cannot reduce the minimum separation requirements between LPFM stations and full-service FM stations that we codified as of the day that the LCRA was enacted (January, 2011). This means that if the FCC wanted to, they could allow contours instead of distance separation to protect translators and other LPFM stations.  In previous orders, the FCC has concluded that there is nothing in the LCRA that specifies power levels.  Therefore, an argument can be made that the LP-10 minimum distance separation tables can be used as they were codified when the LCRA was enacted. By using these charts instead of the LP-100 charts, it would open up more opportunities and still leave a buffer zone to most full-service stations.

The FCC would eventually allow a form of contour protection, specifically in the form of the second adjacent channel waiver where it can be shown that the interfering contour of the LPFM does not overlap the protected service contour of the second-adjacent channel short-spaced station.

Text of Current Rule

Minimum separation requirements for LPFM stations are listed in the following paragraphs. Except as noted below, an LPFM station will not be authorized unless the co-channel, and first- and second-adjacent channel separations are met. An LPFM station need not satisfy the third-adjacent channel separations listed in paragraphs (a) through (c) in order to be authorized. The third-adjacent channel separations are included for use in determining for purposes of Section 73.810 which third-adjacent channel interference regime applies to an LPFM station. 

Minimum distances for co-channel and first-adjacent channel are separated into two columns. The left-hand column lists the required minimum separation to protect other stations and the right-hand column lists (for informational purposes only) the minimum distance necessary for the LPFM station to receive no interference from other stations assumed to be operating at the maximum permitted facilities for the station class. For second-adjacent channel, the required minimum distance separation is sufficient to avoid interference received from other stations.

(a)(1) An LPFM station will not be authorized initially unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period, authorized LPFM stations, LPFM station applications that were timely-filed within a previous window, and vacant FM allotments. LPFM modification applications must either meet the distance separations in the following table or, if short-spaced, not lessen the spacing to subsequently authorized stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second and
third adjacent
channel
minimum
separation
(km)
 
Station class protected by LPFM Required For no interference received from max. class facility Required For no interference received from max. class facility Required  
LPFM24241414None
D242413136
A6792565629
B181119747446
B112143979767
C378119676740
C291143808453
C111117810011173
C012219311113084
C13020312014293

(a)(2) LPFM stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (a)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000, broadcasts a radio reading service via a subcarrier frequency.

(b)(1) In addition to meeting or exceeding the minimum separations in paragraph (a), new LPFM stations will not be authorized in Puerto Rico or the Virgin Islands unless the minimum distance separations in the following tables are met with respect to authorized or proposed FM stations:

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second and
third adjacent
channel
minimum
separation
(km)
 
Station class protected by LPFM Required For no interference received from max. class facility Required For no interference received from max. class facility Required  
A80111707042
B195128828253
B13817912312392

Note to paragraphs (a) and (b):  Minimum distance separations towards “grandfathered” superpowered Reserved Band stations are as specified.

Full service FM stations operating within the reserved band (Channels 201-220) with facilities in excess of those permitted in § 73.211(b)(1) or § 73.211(b)(3) shall be protected by LPFM stations in accordance with the minimum distance separations for the nearest class as determined under § 73.211. For example, a Class B1 station operating with facilities that result in a 60 dBu contour that exceeds 39 kilometers but is less than 52 kilometers would be protected by the Class B minimum distance separations. Class D stations with 60 dBu contours that exceed 5 kilometers will be protected by the Class A minimum distance separations. Class B stations with 60 dBu contours that exceed 52 kilometers will be protected as Class C1 or Class C stations depending upon the distance to the 60 dBu contour. No stations will be protected beyond Class C separations.

(c)(1) In addition to meeting the separations specified in paragraphs (a) and (b), LPFM applications must meet the minimum separation requirements in the following table with respect to authorized FM translator stations, cutoff FM translator applications, and FM translator applications filed prior to the release of the Public Notice announcing the LPFM window period.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second and
third adjacent
channel
minimum
separation
(km)
 
Distance to FM translator 60 dBu contour Required For no interference received Required For no interference received Required  
13.3 km or greater3967283521
Greater than 7.3 km, but less than 13.3 km3251212614
7.3 km or less263015168

(d) Existing LPFM stations which do not meet the separations in paragraphs (a) through (c) of this section may be relocated provided that the separation to any short-spaced station is not reduced.

(e)(1) Waiver of the second-adjacent channel separations. The Commission will entertain requests to waive the second-adjacent channel separations in paragraphs (a) through (c) of this section on a case-by-case basis.  In each case, the LPFM station must establish, using methods of predicting interference taking into account all relevant factors, including terrain-sensitive propagation models, that its proposed operations will not result in interference to any authorized radio service. The LPFM station may do so by demonstrating that no actual interference will occur due to intervening terrain or lack of population. The LPFM station may use an undesired/desired signal strength ratio methodology to define areas of potential interference.

(2) Interference.

(A) Upon receipt of a complaint of interference from an LPFM station operating pursuant to a waiver granted under paragraph (e)(1) of this section, the Commission shall notify the identified LPFM station by telephone or other electronic communication within one business day.

(B) An LPFM station that receives a waiver under paragraph (e)(1) of this section shall suspend operation immediately upon notification by the Commission that it is causing interference to the reception of an existing or modified full-service FM station without regard to the location of the station receiving interference. The LPFM station shall not resume operation until such interference has been eliminated or it can demonstrate to the Commission that the interference was not due to emissions from the LPFM station. Short test transmissions may be made during the period of suspended operation to check the efficacy of remedial measures.

(f) Commercial and noncommercial educational stations authorized under subparts B and C of this part, as well as new or modified commercial FM allotments, are not required to adhere to the separations specified in this rule section, even where new or increased interference would be created.

(g) International considerations within the border zones.

(1) Within 320 km of the Canadian border, LPFM stations must meet the following minimum separations with respect to any Canadian stations:

  Co-channel
(km)
First-adjacent channel
(km)
Second-adjacent channel
(km)
Third-adjacent channel
(km)
Intermediate frequency (IF) channel
(km)
A1 & Low Power453021204
A665041407
B1786253529
B9276686612
C111398898819
C124108999828

(2) Within 320 km of the Mexican border, LPFM stations must meet the following separations with respect to any Mexican stations:

  Co-channel
(km)
First-adjacent channel
(km)
Second- and third-adjacent channel
(km)
Intermediate frequency (IF) channel
(km)
Low Power271793
A4332255
AA4736296
B16754458
B91766611
C191807319
C1101009227

(3) The Commission will notify the International Telecommunications Union (ITU) of any LPFM authorizations in the US Virgin Islands. Any authorization issued for a US Virgin Islands LPFM station will include a condition that permits the Commission to modify, suspend or terminate without right to a hearing if found by the Commission to be necessary to conform to any international regulations or agreements.

(4) The Commission will initiate international coordination of a LPFM proposal even where the above Canadian and Mexican spacing tables are met, if it appears that such coordination is necessary to maintain compliance with international agreements.

(5)(i) LPFM stations located within 125 kilometers of the Mexican border are limited to 50 watts (0.05 kW) ERP, a 60 dBu service contour of 8.7 kilometers and a 34 dBu interfering contour of 32 kilometers in the direction of the Mexican border. LPFM stations may operate up to 100 watts in all other directions.

(ii) LPFM stations located between 125 kilometers and 320 kilometers from the Mexican border may operate in excess of 50 watts, up to a maximum ERP of 100 watts. However, in no event shall the location of the 60 dBu contour lie within 116.3 kilometers of the Mexican border.

(iii) Applications for LPFM stations within 320 kilometers of the Canadian border may employ an ERP of up to a maximum of 100 watts. The distance to the 34 dBu interfering contour may not exceed 60 kilometers in any direction.

Rule History

73.807 Interference protection to full service FM stations.

Minimum separation requirements for LP100 and LP10 stations, as defined in § 73.811 and § 73.853 of this part, are listed in the following paragraphs. An LPFM station will not be authorized unless these separations are met. Minimum distances for co-channel and first-adjacent channel are separated into two columns. The left-hand column lists the required minimum separation to protect other stations and the right-hand column lists (for informational purposes only) the minimum distance necessary for the LPFM station to receive no interference from other stations. For second-adjacent channels and IF channels, the required minimum distance separation is sufficient to avoid interference received from other stations

(a) An LP100 station will not be authorized initially unless the minimum distance separations in the following table are met with respect to authorized FM stations, timely filed applications for new and existing FM stations, authorized LP100 stations, LP100 station applications that were timelyfiled within a previous window, and vacant FM allotments. LP100 stations are not required to protect LP10 stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LP100 Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

24

24

14

14

None

None  

D

24

24

13

13

6

4  

A

67

92

56

56

29

7  

B1

87

119

74

74

46

9  

B

112

143

97

97

67

12  

C3

78

119

67

67

40

9  

C2

91

143

80

84

53

12  

C1

111

178

100

111

73

20  

C

130

203

120

142

93

28  

(b) An LP10 station will not be authorized unless the minimum distance separations are met with respect to authorized FM stations, timely-filed applications for new and existing FM stations, vacant FM allotments, or LPFM stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LPFM Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

16 22 10 11 None None  

LP10

13

13

8

8

None

None  

D

16

21

10

11

6

2  

A

59

90

53

53

29

5  

B1

77

117

70

70

45

8  

B

99

141

91

91

66

11  

C3

69

117

64

64

39

8  

C2

82

141

77

81

52

11  

C1

103

175

97

108

73

18  

C

122

201

116

140

92

26  

(c) In addition to meeting or exceeding the minimum separations for Class LP100 and Class LP10 stations in paragraphs (a) and (b) of this section, new LP100 and LP10 stations will not be authorized in Puerto Rico or the Virgin Islands unless the minimum distance separations are met with respect to authorized or proposed FM stations:

(1) LP100 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP100

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

80

111

70

70

42

9

B1

95

128

82

82

53

11

B

138

179

123

123

92

20

(2) LP10 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP10

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

72

108

66

66

42

8

B1

84

125

78

78

53

9

B

126

177

118

118

92

18

Note to paragraphs (a), (b), and (c):

Minimum distance separations towards ‘‘grandfathered’’ superpowered Reserved Band stations, are as specified. Full service FM stations operating within the reserved band (Channels 201–220) with facilities in excess of those permitted in § 73.211(b)(1) or § 73.211(b)(3) shall be protected by LPFM stations in accordance with the minimum distance separations for the nearest class as determined under § 73.211. For example, a Class B1 station operating with facilities that result in a 60 dBu contour that exceeds 39 kilometers but is less than 52 kilometers would be protected by the Class B minimum distance separations. Class D stations with 60 dBu contours that exceed 5 kilometers will be protected by the Class A minimum distance separations. Class B stations with 60 dBu contours that exceed 52 kilometers will be protected as Class C1 or Class C stations depending upon the distance to the 60 dBu contour. No stations will be protected beyond Class C separations.

(d) In addition to meeting the separations (a) through (c), LPFM applications must meet the minimum separation requirements with respect to authorized FM translator stations, cutoff FM translator applications, and FM translator applications filed prior to the release of the Public Notice announcing the LPFM window period:

(1) LP100 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received

 

13.3 km or greater

39

67

28

35

21

5

Greater than 7.3 km, but less than 13.3 km

32

51

21

26

14

5

7.3 km or less

26

30

15

16

8

5

(2) LP10 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received

 

13.3 km or greater

30

65

25

33

20

3

Greater than 7.3 km, but less than 13.3 km

24

49

18

23

14

3

7.3 km or less

18

28

12

14

8

3

(e) Existing Class LP100 and LP10 stations which do not meet the separations in paragraphs (a) through (e) of this section may be relocated provided that the separation to any short-spaced station is not reduced.

(f) Commercial and noncommercial educational stations authorized under subparts B and C of this part, as well as new or modified commercial FM allotments, are not required to adhere to the separations specified in this rule section, even where new or increased interference would be created.

(g) International considerations within the border zones.

(1) Within 320 km of the Canadian border, LP100 stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

45

30

21

20

4

A

66

50

41

40

7

B1

78

62

53

52

9

B

92

76

68

66

12

C1

113

98

89

88

19

C

124

108

99

98

28

(2) Within 320 km of the Mexican border, LP100 stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A

43

32

25

5

AA

47

36

29

6

B1

67

54

45

8

B

91

76

66

11

C1

91

80

73

19

C

110

100

92

27

(3) Within 320 km of the Canadian border, LP10 stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

33

25

23

19

3

A

53

45

43

39

5

B1

65

57

55

51

8

B

79

71

70

66

11

C1

101

93

91

87

18

C

108

102

100

97

26

(4) Within 320 km of the Mexican border, LP10 stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A

34

29

24

5

AA

39

33

29

5

B1

57

50

45

8

B

79

71

66

11

C1

83

77

73

18

C

102

96

92

26

(5) The Commission will notify the International Telecommunications Union (ITU) of any LPFM authorizations in the US Virgin Islands. Any authorization issued for a US Virgin Islands LPFM station will include a condition that permits the Commission to modify, suspend or terminate without right to a hearing if found by the Commission to be necessary to conform to any international regulations or agreements.

(6) The Commission may, at its option, initiate international coordination of a LPFM proposal even where the above Canadian and Mexican spacing tables are met, if it appears that such coordination is necessary to maintain compliance with international agreements.

65 FR 7640 (Feb 15, 2000).

73.807 Interference protection to full service FM stations.

Minimum separation requirements for LP100 and LP10 stations, as defined in §§ 73.811 and § 73.853 of this part, are listed in the following paragraphs. An LPFM station will not be authorized unless these separations are met. Minimum distances for co-channel and first-adjacent channel are separated into two columns. The left-hand column lists the required minimum separation to protect other stations and the right-hand column lists (for informational purposes only) the minimum distance necessary for the LPFM station to receive no interference from other stations assumed to operating at the maximum permitted facilities for the station class. For second-adjacent channels and IF channels, the required minimum distance separation is sufficient to avoid interference received from other stations

(a)(1) An LP100 station will not be authorized initially unless the minimum distance separations in the following table are met with respect to authorized FM stations, timely filed applications for new and existing FM stationsfiled prior to the release of the public notice announcing an LPFM window period for LP100 stations, authorized LP100 stations, LP100 station applications that were timely-filed within a previous window, and vacant FM allotments. LP100 stations are not required to protect LP10 stations. LPFM modification applications must either meet the distance separations in the following table or, if short-spaced, not lessen the spacing to subsequently authorized stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LP100 Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

24

24

14

14

None 0

None 0  

D

24

24

13

13

6

4 3  

A

67

92

56

56

29

7 6  

B1

87

119

74

74

46

9  

B

112

143

97

97

67

12  

C3

78

119

67

67

40

9  

C2

91

143

80

84

53

12  

C1

111

178

100

111

73

20  

C

130

203

120

142

93

28  

(a)(2) LP100 stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (a)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 (the adoption date of this MO&O) broadcasts a radio reading service via a subcarrier frequency

(b)(1)  An LP10 station will not be authorized unless the minimum distance separations in the following table are met with respect to authorized FM stations, timely-filed applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period for LP10 stations, vacant FM allotments, or LPFM stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LPFM Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

16 22 10 11 None 0 None 0  

LP10

13

13

8

8

None 0

None 0  

D

16

21

10

11

6

2  

A

59

90

53

53

29

5  

B1

77

117

70

70

45

8  

B

99

141

91

91

66

11  

C3

69

117

64

64

39

8  

C2

82

141

77

81

52

11  

C1

103

175

97

108

73

18  

C

122

201

116

140

92

26  

(b)(2) LP10 stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (b)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 (the adoption date of this MO&O) broadcasts a radio reading service via a subcarrier frequency

(c) In addition to meeting or exceeding the minimum separations for Class LP100 and Class LP10 stations in paragraphs (a) and (b) of this section, new LP100 and LP10 stations will not be authorized in Puerto Rico or the Virgin Islands unless the minimum distance separationsin the following tables are met with respect to authorized or proposed FM stations:

(1) LP100 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP100

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

80

111

70

70

42

9

B1

95

128

82

82

53

11

B

138

179

123

123

92

20

(2) LP10 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP10

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

72

108

66

66

42

8

B1

84

125

78

78

53

9

B

126

177

118

118

92

18

Note to paragraphs (a), (b), and (c):

Minimum distance separations towards ‘‘grandfathered’’ superpowered Reserved Band stations, are as specified.

Full service FM stations operating within the reserved band (Channels 201–220) with facilities in excess of those permitted in § 73.211(b)(1) or § 73.211(b)(3) shall be protected by LPFM stations in accordance with the minimum distance separations for the nearest class as determined under § 73.211. For example, a Class B1 station operating with facilities that result in a 60 dBu contour that exceeds 39 kilometers but is less than 52 kilometers would be protected by the Class B minimum distance separations. Class D stations with 60 dBu contours that exceed 5 kilometers will be protected by the Class A minimum distance separations. Class B stations with 60 dBu contours that exceed 52 kilometers will be protected as Class C1 or Class C stations depending upon the distance to the 60 dBu contour. No stations will be protected beyond Class C separations.

(d) In addition to meeting the separations (a) through (c), LPFM applications must meet the minimum separation requirements with respect to authorized FM translator stations, cutoff FM translator applications, and FM translator applications filed prior to the release of the Public Notice announcing the LPFM window period:

(1) LP100 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received
 

13.3 km or greater

39

67

28

35

21

5

Greater than 7.3 km, but less than 13.3 km

32

51

21

26

14

5

7.3 km or less

26

30

15

16

8

5

(2) LP10 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received
 

13.3 km or greater

30

65

25

33

20

3

Greater than 7.3 km, but less than 13.3 km

24

49

18

23

14

3

7.3 km or less

18

28

12

14

8

3

(e) Existing Class LP100 and LP10 stations which do not meet the separations in paragraphs (a) through (e) of this section may be relocated provided that the separation to any short-spaced station is not reduced.

(f) Commercial and noncommercial educational stations authorized under subparts B and C of this part, as well as new or modified commercial FM allotments, are not required to adhere to the separations specified in this rule section, even where new or increased interference would be created.

(g) International considerations within the border zones.

(1) Within 320 km of the Canadian border, LP100 stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

45

30

21

20

4

A

66

50

41

40

7

B1

78

62

53

52

9

B

92

76

68

66

12

C1

113

98

89

88

19

C

124

108

99

98

28

(2) Within 320 km of the Mexican border, LP100 stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

Low Power

27 17 9 3

A

43

32

25

5

AA

47

36

29

6

B1

67

54

45

8

B

91

76

66

11

C1

91

80

73

19

C

110

100

92

27

(3) Within 320 km of the Canadian border, LP10 stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

33

25

23 20

19

3

A

53

45

43 40

39

5

B1

65

57

55 52

51

8

B

79

71

70 67

66

11

C1

101

93

91 88

87

18

C

108

102

100 98

97

26

(4) Within 320 km of the Mexican border, LP10 stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

Low Power

19 13 9 2

A

34

29

24

5

AA

39

33

29

5

B1

57

50

45

8

B

79

71

66

11

C1

83

77

73

18

C

102

96

92

26

(5) The Commission will notify the International Telecommunications Union (ITU) of any LPFM authorizations in the US Virgin Islands. Any authorization issued for a US Virgin Islands LPFM station will include a condition that permits the Commission to modify, suspend or terminate without right to a hearing if found by the Commission to be necessary to conform to any international regulations or agreements.

(6) The Commission may, at its option, will initiate international coordination of a LPFM proposal even where the above Canadian and Mexican spacing tables are met, if it appears that such coordination is necessary to maintain compliance with international agreements.

65 FR 67302 (Nov 9, 2000).

73.807 Interference protection to full service FM stations.

Minimum separation requirements for LP100 and LP10 stations, as defined in §§ 73.811 and § 73.853 are listed in the following paragraphs. An LPFM station will not be authorized unless these separations are met. Minimum distances for co-channel and first-adjacent channel are separated into two columns. The left-hand column lists the required minimum separation to protect other stations and the right-hand column lists (for informational purposes only) the minimum distance necessary for the LPFM station to receive no interference from other stations assumed to operating at the maximum permitted facilities for the station class. For second-adjacent channels and IF channels, the required minimum distance separation is sufficient to avoid interference received from other stations

(a)(1) An LP100 station will not be authorized initially unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period for LP100 stations, authorized LP100 stations, LP100 station applications that were timely-filed within a previous window, and vacant FM allotments. LP100 stations are not required to protect LP10 stations. LPFM modification applications must either meet the distance separations in the following table or, if short-spaced, not lessen the spacing to subsequently authorized stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LP100 Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

24

24

14

14

0 None 0 None  

D

24

24

13

13

6

3  

A

67

92

56

56

29

6  

B1

87

119

74

74

46

9  

B

112

143

97

97

67

12  

C3

78

119

67

67

40

9  

C2

91

143

80

84

53

12  

C1

111

178

100

111

73

20  

C0

122 193 111 130 84 22  

C

130

203

120

142

93

28  

(a)(2) LP100 stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (a)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 (the adoption date of this MO&O) broadcasts a radio reading service via a subcarrier frequency

(b)(1)  An LP10 station will not be authorized unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period for LP10 stations, vacant FM allotments, or LPFM stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LPFM Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

16 22 10 11 0 None 0 None  

LP10

13

13

8

8

0 None

0 None  

D

16

21

10

11

6

2  

A

59

90

53

53

29

5  

B1

77

117

70

70

45

8  

B

99

141

91

91

66

11  

C3

69

117

64

64

39

8  

C2

82

141

77

81

52

11  

C1

103

175

97

108

73

18  

C0

114 190 99 127 84 21  

C

122

201

116

140

92

26  

(b)(2) LP10 stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (b)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 (the adoption date of this MO&O) broadcasts a radio reading service via a subcarrier frequency

(c) In addition to meeting or exceeding the minimum separations for Class LP100 and Class LP10 stations in paragraphs (a) and (b) of this section, new LP100 and LP10 stations will not be authorized in Puerto Rico or the Virgin Islands unless the minimum distance separationsin the following tables are met with respect to authorized or proposed FM stations:

(1) LP100 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP100

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

80

111

70

70

42

9

B1

95

128

82

82

53

11

B

138

179

123

123

92

20

(2) LP10 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP10

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

72

108

66

66

42

8

B1

84

125

78

78

53

9

B

126

177

118

118

92

18

Note to paragraphs (a), (b), and (c):

Minimum distance separations towards ‘‘grandfathered’’ superpowered Reserved Band stations, are as specified.

Full service FM stations operating within the reserved band (Channels 201–220) with facilities in excess of those permitted in § 73.211(b)(1) or § 73.211(b)(3) shall be protected by LPFM stations in accordance with the minimum distance separations for the nearest class as determined under § 73.211. For example, a Class B1 station operating with facilities that result in a 60 dBu contour that exceeds 39 kilometers but is less than 52 kilometers would be protected by the Class B minimum distance separations. Class D stations with 60 dBu contours that exceed 5 kilometers will be protected by the Class A minimum distance separations. Class B stations with 60 dBu contours that exceed 52 kilometers will be protected as Class C1 or Class C stations depending upon the distance to the 60 dBu contour. No stations will be protected beyond Class C separations.

(d) In addition to meeting the separations (a) through (c), LPFM applications must meet the minimum separation requirements with respect to authorized FM translator stations, cutoff FM translator applications, and FM translator applications filed prior to the release of the Public Notice announcing the LPFM window period:

(1) LP100 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received
 

13.3 km or greater

39

67

28

35

21

5

Greater than 7.3 km, but less than 13.3 km

32

51

21

26

14

5

7.3 km or less

26

30

15

16

8

5

(2) LP10 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received
 

13.3 km or greater

30

65

25

33

20

3

Greater than 7.3 km, but less than 13.3 km

24

49

18

23

14

3

7.3 km or less

18

28

12

14

8

3

(e) Existing Class LP100 and LP10 stations which do not meet the separations in paragraphs (a) through (e) of this section may be relocated provided that the separation to any short-spaced station is not reduced.

(f) Commercial and noncommercial educational stations authorized under subparts B and C of this part, as well as new or modified commercial FM allotments, are not required to adhere to the separations specified in this rule section, even where new or increased interference would be created.

(g) International considerations within the border zones.

(1) Within 320 km of the Canadian border, LP100 stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

45

30

21

20

4

A

66

50

41

40

7

B1

78

62

53

52

9

B

92

76

68

66

12

C1

113

98

89

88

19

C

124

108

99

98

28

(2) Within 320 km of the Mexican border, LP100 stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

Low Power

27 17 9 3

A

43

32

25

5

AA

47

36

29

6

B1

67

54

45

8

B

91

76

66

11

C1

91

80

73

19

C

110

100

92

27

(3) Within 320 km of the Canadian border, LP10 stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

33

25

20

19

3

A

53

45

40

39

5

B1

65

57

52

51

8

B

79

71

67

66

11

C1

101

93

88

87

18

C

108

102

98

97

26

(4) Within 320 km of the Mexican border, LP10 stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

Low Power

19 13 9 2

A

34

29

24

5

AA

39

33

29

5

B1

57

50

45

8

B

79

71

66

11

C1

83

77

73

18

C

102

96

92

26

(5) The Commission will notify the International Telecommunications Union (ITU) of any LPFM authorizations in the US Virgin Islands. Any authorization issued for a US Virgin Islands LPFM station will include a condition that permits the Commission to modify, suspend or terminate without right to a hearing if found by the Commission to be necessary to conform to any international regulations or agreements.

(6) The Commission will initiate international coordination of a LPFM proposal even where the above Canadian and Mexican spacing tables are met, if it appears that such coordination is necessary to maintain compliance with international agreements.

65 FR 79779 (Dec 20, 2000)

73.807 Interference protection to full service FM stations.

Minimum separation requirements for LP100 and LP10 stations, as defined in §§ 73.811 and 73.853 are listed in the following paragraphs. An LPFM station will not be authorized unless these the co-channel, first- and second-adjacent and IF channel separations are met. An LPFM station need not satisfy the third-adjacent channel separations listed in paragraphs (a) through (d) in order to be authorized. Minimum distances for co-channel and first-adjacent channel are separated into two columns. The left-hand column lists the required minimum separation to protect other stations and the right-hand column lists (for informational purposes only) the minimum distance necessary for the LPFM station to receive no interference from other stations assumed to be operating at the maximum permitted facilities for the station class. For second-adjacent channels and IF channels, the required minimum distance separation is sufficient to avoid interference received from other stations.

(a)(1) An LP100 station will not be authorized initially unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications that were timely-filed within a previous window, and vacant FM allotments. LP100 stations are not required to protect LP10 stations. LPFM modification applications must either meet the distance separations in the following table or, if short-spaced, not lessen the spacing to subsequently authorized stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LP100 Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

24

24

14

14

0

 0  

D

24

24

13

13

6

3  

A

67

92

56

56

29

6  

B1

87

119

74

74

46

9  

B

112

143

97

97

67

12  

C3

78

119

67

67

40

9  

C2

91

143

80

84

53

12  

C1

111

178

100

111

73

20  

C0

122 193 111 130 84 22  

C

130

203

120

142

93

28  

(a)(2) LP100 stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (a)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 (the adoption date of this MO&O) broadcasts a radio reading service via a subcarrier frequency

(b)(1)  An LP10 station will not be authorized unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period for LP10 stations, vacant FM allotments, or LPFM stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LPFM Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

16 22 10 11 0 0  

LP10

13

13

8

8

0

0  

D

16

21

10

11

6

2  

A

59

90

53

53

29

5  

B1

77

117

70

70

45

8  

B

99

141

91

91

66

11  

C3

69

117

64

64

39

8  

C2

82

141

77

81

52

11  

C1

103

175

97

108

73

18  

C0

114 190 90 127 84 21  

C

122

201

116

140

92

26  

(b)(2) LP10 stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (b)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 (the adoption date of this MO&O) broadcasts a radio reading service via a subcarrier frequency

(c) In addition to meeting or exceeding the minimum separations for Class LP100 and Class LP10 stations in paragraphs (a) and (b) of this section, new LP100 and LP10 stations will not be authorized in Puerto Rico or the Virgin Islands unless the minimum distance separations in the following tables are met with respect to authorized or proposed FM stations:

(1) LP100 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP100

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

80

111

70

70

42

9

B1

95

128

82

82

53

11

B

138

179

123

123

92

20

(2) LP10 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP10

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

72

108

66

66

42

8

B1

84

125

78

78

53

9

B

126

177

118

118

92

18

Note to paragraphs (a), (b), and (c):

Minimum distance separations towards ‘‘grandfathered’’ superpowered Reserved Band stations, are as specified.

Full service FM stations operating within the reserved band (Channels 201–220) with facilities in excess of those permitted in § 73.211(b)(1) or § 73.211(b)(3) shall be protected by LPFM stations in accordance with the minimum distance separations for the nearest class as determined under § 73.211. For example, a Class B1 station operating with facilities that result in a 60 dBu contour that exceeds 39 kilometers but is less than 52 kilometers would be protected by the Class B minimum distance separations. Class D stations with 60 dBu contours that exceed 5 kilometers will be protected by the Class A minimum distance separations. Class B stations with 60 dBu contours that exceed 52 kilometers will be protected as Class C1 or Class C stations depending upon the distance to the 60 dBu contour. No stations will be protected beyond Class C separations.

(d) In addition to meeting the separations (a) through (c), LPFM applications must meet the minimum separation requirements with respect to authorized FM translator stations, cutoff FM translator applications, and FM translator applications filed prior to the release of the Public Notice announcing the LPFM window period:

(1) LP100 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received
 

13.3 km or greater

39

67

28

35

21

5

Greater than 7.3 km, but less than 13.3 km

32

51

21

26

14

5

7.3 km or less

26

30

15

16

8

5

(2) LP10 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received
 

13.3 km or greater

30

65

25

33

20

3

Greater than 7.3 km, but less than 13.3 km

24

49

18

23

14

3

7.3 km or less

18

28

12

14

8

3

(e) Existing Class LP100 and LP10 stations which do not meet the separations in paragraphs (a) through (e) of this section may be relocated provided that the separation to any short-spaced station is not reduced.

(f) Commercial and noncommercial educational stations authorized under subparts B and C of this part, as well as new or modified commercial FM allotments, are not required to adhere to the separations specified in this rule section, even where new or increased interference would be created.

(g) International considerations within the border zones.

(1) Within 320 km of the Canadian border, LP100 stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

45

30

21

20

4

A

66

50

41

40

7

B1

78

62

53

52

9

B

92

76

68

66

12

C1

113

98

89

88

19

C

124

108

99

98

28

(2) Within 320 km of the Mexican border, LP100 stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

Low Power

27 17 9 3

A

43

32

25

5

AA

47

36

29

6

B1

67

54

45

8

B

91

76

66

11

C1

91

80

73

19

C

110

100

92

27

(3) Within 320 km of the Canadian border, LP10 stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

33

25

20

19

3

A

53

45

40

39

5

B1

65

57

52

51

8

B

79

71

67

66

11

C1

101

93

88

87

18

C

108

102

98

97

26

(4) Within 320 km of the Mexican border, LP10 stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

Low Power

19 13 9 2

A

34

29

24

5

AA

39

33

29

5

B1

57

50

45

8

B

79

71

66

11

C1

83

77

73

18

C

102

96

92

26

(5) The Commission will notify the International Telecommunications Union (ITU) of any LPFM authorizations in the US Virgin Islands. Any authorization issued for a US Virgin Islands LPFM station will include a condition that permits the Commission to modify, suspend or terminate without right to a hearing if found by the Commission to be necessary to conform to any international regulations or agreements.

(6) The Commission will initiate international coordination of a LPFM proposal even where the above Canadian and Mexican spacing tables are met, if it appears that such coordination is necessary to maintain compliance with international agreements.

77 FR 20555 (Apr 6, 2012)

73.807 Interference protection to full service FM stations.

Minimum separation requirements for LP100 and LP10 LPFM stations, as defined in §§ 73.811 and 73.853 are listed in the following paragraphs. An Except as noted below, an LPFM station will not be authorized unless the co-channel, first- and second-adjacent and IF channel separations are met. An LPFM station need not satisfy the third-adjacent channel separations listed in paragraphs (a) through (d) (c) in order to be authorized. Minimum distances for co-channel and first-adjacent channel are separated into two columns. The left-hand column lists the required minimum separation to protect other stations and the right-hand column lists (for informational purposes only) the minimum distance necessary for the LPFM station to receive no interference from other stations assumed to be operating at the maximum permitted facilities for the station class. For second-adjacent channels and IF channels channel, the required minimum distance separation is sufficient to avoid interference received from other stations.

(a)(1) An LP100 LPFM station will not be authorized initially unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period, authorized LPFM stations, LPFM station applications that were timely-filed within a previous window, and vacant FM allotments. LP100 stations are not required to protect LP10 stations. LPFM modification applications must either meet the distance separations in the following table or, if short-spaced, not lessen the spacing to subsequently authorized stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second and Third-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LP100 LPFM Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

24

24

14

14

0 None

0  

D

24

24

13

13

6

3  

A

67

92

56

56

29

6  

B1

87

119

74

74

46

9  

B

112

143

97

97

67

12  

C3

78

119

67

67

40

9  

C2

91

143

80

84

53

12  

C1

111

178

100

111

73

20  

C0

122 193 111 130 84 22  

C

130

203

120

142

93

28  

(a)(2) LP100 LPFM stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (a)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 broadcasts a radio reading service via a subcarrier frequency

(b)(1)  An LP10 station will not be authorized unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period for LP10 stations, vacant FM allotments, or LPFM stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second-adjacent
channel
minimum
separation
(km)
I.F . Channel minimum separations 10.6 or 10.8 MHz  
Station class protected by LPFM Required For no interference received from max. class facility Required For no interference received from max. class facility Required    

LP100

16 22 10 11 0 0  

LP10

13

13

8

8

0

0  

D

16

21

10

11

6

2  

A

59

90

53

53

29

5  

B1

77

117

70

70

45

8  

B

99

141

91

91

66

11  

C3

69

117

64

64

39

8  

C2

82

141

77

81

52

11  

C1

103

175

97

108

73

18  

C0

114 190 90 127 84 21  

C

122

201

116

140

92

26  

(b)(2) LP10 stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (b)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 (the adoption date of this MO&O) broadcasts a radio reading service via a subcarrier frequency

(c) (b) In addition to meeting or exceeding the minimum separations for Class LP100 and Class LP10 stations in paragraphs in paragraph (a) and (b) of this section, new LP100 and LP10 LPFM stations will not be authorized in Puerto Rico or the Virgin Islands unless the minimum distance separations in the following tables are met with respect to authorized or proposed FM stations:

(1) LP100 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP100 LPFM

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second and third-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

80

111

70

70

42

9

B1

95

128

82

82

53

11

B

138

179

123

123

92

20

(2) LP10 Stations in Puerto Rico and the Virgin Islands:

Station class protected by LP10

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

72

108

66

66

42

8

B1

84

125

78

78

53

9

B

126

177

118

118

92

18

Note to paragraphs (a), and (b), and (c):

Minimum distance separations towards ‘‘grandfathered’’ superpowered Reserved Band stations, are as specified.

Full service FM stations operating within the reserved band (Channels 201–220) with facilities in excess of those permitted in § 73.211(b)(1) or § 73.211(b)(3) shall be protected by LPFM stations in accordance with the minimum distance separations for the nearest class as determined under § 73.211. For example, a Class B1 station operating with facilities that result in a 60 dBu contour that exceeds 39 kilometers but is less than 52 kilometers would be protected by the Class B minimum distance separations. Class D stations with 60 dBu contours that exceed 5 kilometers will be protected by the Class A minimum distance separations. Class B stations with 60 dBu contours that exceed 52 kilometers will be protected as Class C1 or Class C stations depending upon the distance to the 60 dBu contour. No stations will be protected beyond Class C separations.

(d) (c) In addition to meeting the separations (a) through (c) and (b), LPFM applications must meet the minimum separation requirements in the following table with respect to authorized FM translator stations, cutoff FM translator applications, and FM translator applications filed prior to the release of the Public Notice announcing the LPFM window period:

(1) LP100 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second and third-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received
 

13.3 km or greater

39

67

28

35

21

5

Greater than 7.3 km, but less than 13.3 km

32

51

21

26

14

5

7.3 km or less

26

30

15

16

8

5

(2) LP10 stations:       

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second-adjacent
channel
minimum
separation
(km)—required

I.F . Channel minimum separations 10.6 or 10.8 MHz

Required

For no interference received

Required

For no interference
received

 

13.3 km or greater

30

65

25

33

20

3

Greater than 7.3 km, but less than 13.3 km

24

49

18

23

14

3

7.3 km or less

18

28

12

14

8

3

(e) (d) Existing Class LP100 and LP10 LPFM stations which do not meet the separations in paragraphs (a) through (e) (c) of this section may be relocated provided that the separation to any short-spaced station is not reduced.

(e)(1) Waiver of the second-adjacent channel separations. The Commission will entertain requests to waive the second-adjacent channel separations in paragraphs (a) through (c) of this section on a case-by-case basis. In each case, the LPFM station must establish, using methods of predicting interference taking into account all relevant factors, including terrain-sensitive propagation models, that its proposed operations will not result in interference to any authorized radio service. The LPFM station may do so by demonstrating that no actual interference will occur due to intervening terrain or lack of population. The LPFM station may use an undesired/desired signal strength ratio methodology to define areas of potential interference.

(2) Interference.

(i) Upon receipt of a complaint of interference from an LPFM station operating pursuant to a waiver granted under paragraph (e)(1) of this section, the Commission shall notify the identified LPFM station by telephone or other electronic communication within one business day.

(ii) An LPFM station that receives a waiver under paragraph (e)(1) of this section shall suspend operation immediately upon notification by the Commission that it is causing interference to the reception of an existing or modified full-service FM station without regard to the location of the station receiving interference. The LPFM station shall not resume operation until such interference has been eliminated or it can demonstrate to the Commission that the interference was not due to emissions from the LPFM station. Short test transmissions may be made during the period of suspended operation to check the efficacy of remedial measures.

(f) Commercial and noncommercial educational stations authorized under subparts B and C of this part, as well as new or modified commercial FM allotments, are not required to adhere to the separations specified in this rule section, even where new or increased interference would be created.

(g) International considerations within the border zones.

(1) Within 320 km of the Canadian border, LP100 LPFM stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

45

30

21

20

4

A

66

50

41

40

7

B1

78

62

53

52

9

B

92

76

68

66

12

C1

113

98

89

88

19

C

124

108

99

98

28

(2) Within 320 km of the Mexican border, LP100 LPFM stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

Low Power

27 17 9 3

A

43

32

25

5

AA

47

36

29

6

B1

67

54

45

8

B

91

76

66

11

C1

91

80

73

19

C

110

100

92

27

(3) Within 320 km of the Canadian border, LP10 stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

33

25

20

19

3

A

53

45

40

39

5

B1

65

57

52

51

8

B

79

71

67

66

11

C1

101

93

88

87

18

C

108

102

98

97

26

(4) Within 320 km of the Mexican border, LP10 stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

Low Power

19 13 9 2

A

34

29

24

5

AA

39

33

29

5

B1

57

50

45

8

B

79

71

66

11

C1

83

77

73

18

C

102

96

92

26

(5) (3) The Commission will notify the International Telecommunications Union (ITU) of any LPFM authorizations in the US Virgin Islands. Any authorization issued for a US Virgin Islands LPFM station will include a condition that permits the Commission to modify, suspend or terminate without right to a hearing if found by the Commission to be necessary to conform to any international regulations or agreements.

 (6) (4) The Commission will initiate international coordination of a LPFM proposal even where the above Canadian and Mexican spacing tables are met, if it appears that such coordination is necessary to maintain compliance with international agreements.

78 FR 2102 (Jan 9, 2013)

Minimum separation requirements for LPFM stations are listed in the following paragraphs.  Except as noted below, an LPFM station will not be authorized unless the co-channel, and first- and second-adjacent channel separations are met.  An LPFM station need not satisfy the third-adjacent channel separations listed in paragraphs (a) through (c) in order to be authorized.  The third-adjacent channel separations are included for use in determining for purposes of Section 73.810 which third-adjacent channel interference regime applies to an LPFM station. 

Minimum distances for co-channel and first-adjacent channel are separated into two columns.  The left-hand column lists the required minimum separation to protect other stations and the right-hand column lists (for informational purposes only) the minimum distance necessary for the LPFM station to receive no interference from other stations assumed to be operating at the maximum permitted facilities for the station class.  For second-adjacent channel, the required minimum distance separation is sufficient to avoid interference received from other stations. 

(a)(1) An LPFM station will not be authorized initially unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period, authorized LPFM stations, LPFM station applications that were timely-filed within a previous window, and vacant FM allotments.  LPFM modification applications must either meet the distance separations in the following table or, if short-spaced, not lessen the spacing to subsequently authorized stations.

  Co-channel minimum separation (km) First-adjacent channel
minimum separation (km)
Second and
third adjacent
channel
minimum
separation
(km)
 
Station class protected by LPFM Required For no interference received from max. class facility Required For no interference received from max. class facility Required  

LPFM

24

24

14

14

None

 

D

24

24

13

13

6

 

A

67

92

56

56

29

 

B1

87

119

74

74

46

 

B

112

143

97

97

67

 

C3

78

119

67

67

40

 

C2

91

143

80

84

53

 

C1

111

178

100

111

73

 

C0

122

193

111

130

84

 

C

130

203

120

142

93

 

(a)(2) LPFM stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (a)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000, broadcasts a radio reading service via a subcarrier frequency.

(b)(1) In addition to meeting or exceeding the minimum separations in paragraph (a), new LPFM stations will not be authorized in Puerto Rico or the Virgin Islands unless the minimum distance separations in the following tables are met with respect to authorized or proposed FM stations:

Station class protected by LPFM

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second and
third adjacent
channel
minimum
separation
(km)—required

Required

For no interference received from max. class facility

Required

For no interference
received
from
max. class
facility

A

80

111

70

70

42

B1

95

128

82

82

53

B

138

179

123

123

92

Note to paragraphs (a) and (b):  Minimum distance separations towards “grandfathered” superpowered Reserved Band stations are as specified.

Full service FM stations operating within the reserved band (Channels 201-220) with facilities in excess of those permitted in § 73.211(b)(1) or § 73.211(b)(3) shall be protected by LPFM stations in accordance with the minimum distance separations for the nearest class as determined under § 73.211. For example, a Class B1 station operating with facilities that result in a 60 dBu contour that exceeds 39 kilometers but is less than 52 kilometers would be protected by the Class B minimum distance separations. Class D stations with 60 dBu contours that exceed 5 kilometers will be protected by the Class A minimum distance separations. Class B stations with 60 dBu contours that exceed 52 kilometers will be protected as Class C1 or Class C stations depending upon the distance to the 60 dBu contour. No stations will be protected beyond Class C separations.

(c)(1) In addition to meeting the separations specified in paragraphs (a) and (b), LPFM applications must meet the minimum separation requirements in the following table with respect to authorized FM translator stations, cutoff FM translator applications, and FM translator applications filed prior to the release of the Public Notice announcing the LPFM window period.           

Distance to FM translator 60 dBu contour

Co-channel minimum separation (km)

First-adjacent channel
minimum separation (km)

Second and
third adjacent
channel
minimum
separation
(km)—required

Required

For no interference received

Required

For no interference
received
 

13.3 km or greater

39

67

28

35

21

Greater than 7.3 km, but less than 13.3 km

32

51

21

26

14

7.3 km or less

26

30

15

16

8

(d) Existing LPFM stations which do not meet the separations in paragraphs (a) through (c) of this section may be relocated provided that the separation to any short-spaced station is not reduced.

(e)(1)  Waiver of the second-adjacent channel separations. The Commission will entertain requests to waive the second-adjacent channel separations in paragraphs (a) through (c) of this section on a case-by-case basis.  In each case, the LPFM station must establish, using methods of predicting interference taking into account all relevant factors, including terrain-sensitive propagation models, that its proposed operations will not result in interference to any authorized radio service.  The LPFM station may do so by demonstrating that no actual interference will occur due to intervening terrain or lack of population.  The LPFM station may use an undesired/desired signal strength ratio methodology to define areas of potential interference.

(2)  Interference.

(A)  Upon receipt of a complaint of interference from an LPFM station operating pursuant to a waiver granted under paragraph (e)(1) of this section, the Commission shall notify the identified LPFM station by telephone or other electronic communication within one business day.

(B)  An LPFM station that receives a waiver under paragraph (e)(1) of this section shall suspend operation immediately upon notification by the Commission that it is causing interference to the reception of an existing or modified full-service FM station without regard to the location of the station receiving interference.  The LPFM station shall not resume operation until such interference has been eliminated or it can demonstrate to the Commission that the interference was not due to emissions from the LPFM station.  Short test transmissions may be made during the period of suspended operation to check the efficacy of remedial measures.

(f) Commercial and noncommercial educational stations authorized under subparts B and C of this part, as well as new or modified commercial FM allotments, are not required to adhere to the separations specified in this rule section, even where new or increased interference would be created.

(g) International considerations within the border zones.

(1) Within 320 km of the Canadian border, LPFM stations must meet the following minimum separations with respect to any Canadian stations:

 

Canadian station class

Co-channel (km)

First-adjacent channel (km)

Second-adjacent channel (km)

Third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

A1 & Low Power

45

30

21

20

4

A

66

50

41

40

7

B1

78

62

53

52

9

B

92

76

68

66

12

C1

113

98

89

88

19

C

124

108

99

98

28

(2) Within 320 km of the Mexican border, LPFM stations must meet the following separations with respect to any Mexican stations:

 

Mexican station class

Co-channel (km)

First-adjacent channel (km)

Second- and third-adjacent channel (km)

Intermediate frequency (IF) channel (km)

Low Power

27

17

9

3

A

43

32

25

5

AA

47

36

29

6

B1

67

54

45

8

B

91

76

66

11

C1

91

80

73

19

C

110

100

92

27

(3) The Commission will notify the International Telecommunications Union (ITU) of any LPFM authorizations in the US Virgin Islands.  Any authorization issued for a US Virgin Islands LPFM station will include a condition that permits the Commission to modify, suspend or terminate without right to a hearing if found by the Commission to be necessary to conform to any international regulations or agreements.

(4) The Commission will initiate international coordination of a LPFM proposal even where the above Canadian and Mexican spacing tables are met, if it appears that such coordination is necessary to maintain compliance with international agreements.

(5)(i) LPFM stations located within 125 kilometers of the Mexican border are limited to 50 watts (0.05 kW) ERP, a 60 dBu service contour of 8.7 kilometers and a 34 dBu interfering contour of 32 kilometers in the direction of the Mexican border. LPFM stations may operate up to 100 watts in all other directions.

(ii) LPFM stations located between 125 kilometers and 320 kilometers from the Mexican border may operate in excess of 50 watts, up to a maximum ERP of 100 watts. However, in no event shall the location of the 60 dBu contour lie within 116.3 kilometers of the Mexican border.

(iii) Applications for LPFM stations within 320 kilometers of the Canadian border may employ an ERP of up to a maximum of 100 watts. The distance to the 34 dBu interfering contour may not exceed 60 kilometers in any direction.