Under international and FCC regulations, unlicensed devices are not permitted to cause harmful interference to radiocommunications services. This would include a wide range of radio use, from commercial and military communications to Amateur Radio and Citizens Band to the reception of international shortwave broadcast stations.
Several BPL operators have misunderstood their need to protect the reception of international shortwave broadcasts by the general public. Here are some excerpts from the international Radio Regulations and FCC rules. They establish that the broadcasting service is a radiocommunication service and it is intended for direct reception by the general public. These rules clearly outline why the ITU and FCC require that broadcasting be received without harmful interference from BPL.
RR 1.19 radiocommunication service: A service as defined in this Section involving the transmission, emission and/or reception of radio waves for specific telecommunication purposes.
RR 1.38 broadcasting service: A radiocommunication service in which the transmissions are intended for direct reception by the general public. This service may include sound transmissions, television transmissions or other types of transmission (CS).
RR4.11 Member States recognize that among frequencies which have long-distance propagation characteristics, those in the bands between 5 and 30 MHz are particularly useful for long-distance communications; they agree to make every possible effort to reserve these bands for such communications. Whether frequencies in these bands are used for short- or medium-distance communications, the minimum power necessary shall be used.
RR15.12 Administrations shall take all practicable and necessary steps to ensure that the operation of electrical apparatus or installations of any kind, including power and telecommunication distribution networks, but excluding ISM, does not cause harmful interference to a radiocommunication service and, in particular, to a radionavigation or any other safety service operating in accordance with the provisions of these Regulations.
RR 15.27 § 19 Full particulars relating to harmful interference shall, whenever possible, be given in the form indicated in Appendix 10.
Here are some quotes from FCC rules, which may or may not be modified or supplemented by BPL rules when effective:
FCC 0.111 Functions of the Bureau (ENFORCEMENT BUREAU)
* * *
(a) (4) Resolve complaints regarding radiofrequency interference and complaints regarding radiofrequency equipment and devices, including complaints of violations of sections 302 and 333 of the Communications Act.
NOTE TO PARAGRAPH (a)(4): The Office of Engineering and Technology has shared responsibility for radiofrequency equipment and device complaints.
Sec. 15.5 General conditions of operation.
(a) Persons operating intentional or unintentional radiators shall not be deemed to have any vested or recognizable right to continued use of any given frequency by virtue of prior registration or certification of equipment, or, for power line carrier systems, on the basis of prior notification of use pursuant to Sec. 90.63(g) of this chapter.
(b) Operation of an intentional, unintentional, or incidental radiator is subject to the conditions that no harmful interference is caused and that interference must be accepted that may be caused by the operation of an authorized radio station, by another intentional or unintentional radiator, by industrial, scientific and medical (ISM) equipment, or by an incidental radiator.
(c) The operator of a radio frequency device shall be required to cease operating the device upon notification by a Commission representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected.
Although for the time being, previously installed BPL equipment is operating under the old FCC rules, by Fall of 2006, all equipment will have to be in compliance with the new rules. Although most BPL equipment does have the capability to be certificated under the rules, those rules list 12 frequency bands that are off limits to access BPL using overhead medium-voltage lines. ARRL also wants to understand how utilities and manufacturers will turn off those 12 bands and still be able to protect amateur radio.
Here are the applicable Part 15 rules about the bands prohibited to access BPL using overhead MV wires:
Sec. 15.651(f)(1) Excluded Bands. To protect Aeronautical (land) stations and aircraft receivers, Access BPL operations using overhead medium voltage power lines are prohibited in the frequency bands listed in Table 1. Specifically, such BPL systems shall not place carrier frequencies in these bands.
Table 1. Excluded Frequency Bands
2,850 3,025 kHz
3,400 3,500 kHz
4,650 4,700 kHz
5,450 5,680 kHz
6,525 6,685 kHz
8,815 8,965 kHz
10,005 10,100 kHz
11,275 11,400 kHz
13,260 13,360 kHz
17,900 17,970 kHz
21,924 22,000 kHz
74.8 75.2 MHz
The use of low VHF also needs to be considered carefully against what users are on that spectrum, as well. In some cases, BPL has been seen on the national Red Cross frequency of 47.42 MHz, for example. Other uses of low VHF can include some fire and police, or paging systems.
Under the FCCs rules, the FCC has pre-emption of all RFI matters.