47 C.F.R. § 24.237
Interference protection.
Cite as 47 C.F.R. § 24.237 (2026)
(a) All licensees are required to coordinate their frequency usage with the co-channel or adjacent channel incumbent fixed microwave licensees in the 1850-1990 MHz band. Coordination must occur before initiating operations from any base station. Problems that arise during the coordination process are to be resolved by the parties to the coordination. Licensees are required to coordinate with all users possibly affected, as determined by appendix I to this subpart E (Appendix E of the Memorandum Opinion and Order, GEN Docket No. 90-314, FCC 94-144; TIA Telecommunications Systems Bulletin 10-F, “Interference Criteria for Microwave Systems,” May 1994, (TSB10-F)); or an alternative method agreed to by the parties.
(b) The results of the coordination process need to be reported to the Commission only if the parties fail to agree. Because broadband PCS licensees are required to protect fixed microwave licensees in the 1850-1990 MHz band, the Commission will be involved in the coordination process only upon complaint of interference from a fixed microwave licensee. In such a case, the Commission will resolve the issues.
(c) In all other respects, coordination procedures are to follow the requirements of § 101.103(d) of this chapter to the extent that these requirements are not inconsistent with those specified in this part.
(d) The licensee must perform an engineering analysis to assure that the proposed facilities will not cause interference to existing OFS stations within the coordination distance specified in Table 3 of a magnitude greater than that specified in the criteria set forth in paragraphs (e) and (f) of this section, unless there is prior agreement with the affected OFS licensee. Interference calculations shall be based on the sum of the power received at the terminals of each microwave receiver from all of the applicant's current and proposed PCS operations.
Table 3—Coordination Distances in Kilometers
PCS Base Station Antenna HAAT in Meters
EIRP(W)
5
10
20
50
100
150
200
250
300
500
1000
1500
2000
0.1
90
93
99
110
122
131
139
146
152
173
210
239
263
0.5
96
100
105
116
128
137
145
152
158
179
216
245
269
1
99
103
108
119
131
140
148
155
161
182
219
248
272
2
120
122
126
133
142
148
154
159
164
184
222
250
274
5
154
157
161
168
177
183
189
194
198
213
241
263
282
10
180
183
187
194
203
210
215
220
225
240
268
291
310
20
206
209
213
221
229
236
242
247
251
267
296
318
337
50
241
244
248
255
264
271
277
282
287
302
331
354
374
100
267
270
274
282
291
297
303
308
313
329
358
382
401
200
293
296
300
308
317
324
330
335
340
356
386
409
436
500
328
331
335
343
352
359
365
370
375
391
421
440
1000
354
357
361
369
378
385
391
397
402
418
1200
361
364
368
376
385
392
398
404
409
425
1640
372
375
379
388
397
404
410
416
421
437
2400
384
387
391
399
408
415
423
427
431
3280
396
399
403
412
419
427
435
439
446
(e) For microwave paths of 25 kilometers or less, interference determinations shall be based on the C/I criteria set forth in TIA Telecommunications Systems Bulletin 10-F, “Interference Criteria for Microwave Systems,” May 1994 (TSB10-F).
(f) For microwave paths longer than 25 kilometers, the interference protection criterion shall be such that the interfering signal will not produce more than 1.0 dB degradation of the practical threshold of the microwave receiver for analog system, or such that the interfering signal will not cause an increase in the bit error rate (BER) from 10E-6 to 10E-5 for digital systems.
(g) The development of the C/I ratios and interference criteria specified in paragraphs (e) and (f) of this section and the methods employed to compute the interfering power at the microwave receivers shall follow generally acceptable good engineering practices. The procedures described for computing interfering signal levels in (appendix I to this subpart E Appendix E of the Memorandum Opinion and Order, GEN Docket No. 90-314, FCC 94-144) shall be applied. Alternatively, procedures for determining interfering signal levels and other criteria as may be developed by the Electronics Industries Association (EIA), the Institute of Electrical and Electronics Engineers, Inc. (IEEE), the American National Standards Institute (ANSI) or any other recognized authority will be acceptable to the Commission.
[59 FR 32854, June 24, 1994, as amended at 61 FR 29691, June 21, 1996; 69 FR 75171, Dec. 15, 2004]
- Cross-references to the CFR
- 101.103