While evaluating the Class A10 Petition for Rulemaking, REC has determined that the §73.207 distance separation charts used to determine how far FM stations need to be apart from each other contains many errors. This includes how Class B and B1 stations protected and other issues, including a “compromise” between the NAB and New Jersey Class A FM broadcasters that was codified in the rules back in 1988 that resulted in some artificially lower numbers for Class A that should not be relevant for Class A10. If the originally proposed values were to be utilized, it could cause harmful interference in some situations. Therefore, REC has counter-proposed new values for the §73.207 minimum distance separations based on recalculations of the service contour distances.
We have also proposed new values for the §73.215 minimum distances used as a baseline for stations that are §73.207 short-spaced to use if they wish to propose a directional antenna and/or reduced power. These REC counter-proposed values reflect the fact that A10 is not the lowest class of service, better delineates Class A10 with the next lower class of service (Class A) and fixes some errors where the Class A10 distance is lower than the current Class A distances.
Class A10 has a standard 60 dBu service contour of 31.8 km (rounded to 32 km) and a standard 70 dBu community coverage (city grade) contour of 18.6 km (rounded to 19 km).
REC's position is that because of the nature of the nature of the geography and how distance separation is done, that Class A10 not be available in Puerto Rico and the United States Virgin Islands.
We advise developers and other interested parties to use the REC counter-proposed values, especially where it comes to §73.207 if performing your own impact studies as these would more likely be the codified values if the Class A10 service was ever adopted by the FCC.
REC is in the process of developing programs using these updated distances in order to determine which Class A stations would be able to upgrade, which Class C3 and B1 stations are actually within Class A10 parameters and to determine the impact of the A10 service class on LPFM stations.
For protections to FM allotments in Canada and Mexico, all of our studies for protection to these foreign allotments will be based on Class B1 in both the Canada and Mexico agreements.
REC counter-proposed §73.207 distance separation chart
Proposed distances from the A10 petition shown in italics and parentheses and are NOT the REC proposed values.
Class A10 to station class |
Co-channel |
First-adjacent channel (200 kHz) |
Second & Third adjacent channels (400/600 kHz) |
Intermediate frequency (10.6/10.8 MHz) |
A |
123 |
78 |
35 |
10* |
A10 |
127 |
81 |
35 |
12 |
C3 |
145 |
92 |
42* |
12* (13) |
B1 |
153 (145) |
102 (93) |
49 (45) |
12* (13) |
C2 |
170 |
110 |
55* |
16 |
B |
190 (170) |
132 (110) |
70 (65) |
16 (12) |
C1 |
204 |
137 |
75* |
23 |
C0 |
219 |
156 |
87 |
26 |
C |
230 |
168 |
95* |
30 |
* - Same value as Class A.
REC counter-proposed §73.215 distance separation chart
Proposed distances from the A10 petition shown in italics and parentheses and are NOT the REC proposed values.
Class A10 to station class |
Co-channel |
First-adjacent channel (200 kHz) |
Second & Third adjacent channels (400/600 kHz) |
A |
115 (104) |
72 (59) |
31 (29) |
A10 |
123 (116) |
78 (81) |
33 (31) |
C3 |
129 |
81 (79) |
36* (35) |
B1 |
130 |
83 |
42* |
C2 |
153 |
96 |
49* (48) |
B |
159 |
104 |
63* |
C1 |
188 |
121 |
69* (68) |
C0 |
203 |
140 |
80* (79) |
C |
213 |
152 |
89* (88) |
* - Same value as Class A.