70 FR 1374, Jan. 7, 2005, unless otherwise noted.
This subpart sets out the regulations for Access Broadband over Power Line (Access BPL) devices operating in the 1.705-80 MHz band over medium or low voltage lines.
(a) Excluded Band: A band of frequencies within which Access BPL operations are not permitted.
(b) Exclusion Zone: A geographical area within which Access BPL operations are not permitted in certain frequency bands.
(c) Consultation. The process of communication between an entity operating Access BPL and a licensed public safety or other designated point of contact for the purpose of avoiding potential harmful interference.
(d) Consultation area: A designated geographical area within which consultation with public safety users or other designated point of contact is required before an Access BPL may be operated at designated frequencies.
(e) Low Voltage power line. A power line carrying low voltage, e.g., 240/120 volts from a distribution transformer to a customer's premises.
(f) Medium Voltage power line. A power line carrying between 1,000 to 40,000 volts from a power substation to neighborhoods. Medium voltage lines may be overhead or underground, depending on the power grid network topology.
(g) Access BPL Database. A database operated by an industry-sponsored entity, recognized by the Federal Communications Commission and the National Telecommunications and Information Administration (NTIA), containing information regarding existing and planned Access BPL systems, as required in § 15.615(a) of this chapter.
(a) The provisions of subparts A and B of this part apply to Access BPL devices, except where specifically noted. The provisions of subparts C through F of this part do not apply to Access BPL devices except where specifically noted.
(b) The requirements of this subpart apply only to the radio circuitry that is used to provide carrier current operation for the Access BPL device. Other aspects of the operation of an Access BPL device may be subject to requirements contained elsewhere in this chapter. In particular, an Access BPL device that includes digital circuitry that is not used solely to enable the operation of the radio frequency circuitry used to provide carrier current operation also is subject to the requirements for unintentional radiators in subpart B of this part.
Access BPL equipment shall be subject to Certification as specified in § 15.101.
The marketing of Access BPL equipment must be directed solely to parties eligible to operate the equipment. Eligible parties consist of AC power line public utilities, Access BPL service providers and associates of Access BPL service providers. The responsible party, as defined in § 2.909 of this chapter, is responsible for ensuring that the equipment is marketed only to eligible parties. Marketing of the equipment in any other manner may be considered grounds for revocation of the grant of certification issued for the equipment.
(a) Conducted emission limits. Access BPL is not subject to the conducted emission limits of § 15.107.
(b) Radiated emission limits -
(1) Medium voltage power lines.
(i) Access BPL systems that operate in the frequency range of 1.705 kHz to 30 MHz over medium voltage power lines shall comply with the radiated emission limits for intentional radiators provided in § 15.209.
(ii) Access BPL systems that operate in the frequency range above 30 MHz over medium voltage power lines shall comply with the radiated emission limits provided in § 15.109(b).
(c) Interference Mitigation and Avoidance.
(1) Access BPL systems shall incorporate adaptive interference mitigation techniques to remotely reduce power and adjust operating frequencies, in order to avoid site-specific, local use of the same spectrum by licensed services. These techniques may include adaptive or “notch” filtering, or complete avoidance of frequencies, or bands of frequencies, locally used by licensed radio operations.
(i) For frequencies below 30 MHz, when a notch filter is used to avoid interference to a specific frequency band, the Access BPL system shall be capable of attenuating emissions within that band to a level at least 25 dB below the applicable Part 15 limits.
(ii) For frequencies above 30 MHz, when a notch filter is used to avoid interference to a specific frequency band, the Access BPL system shall be capable of attenuating emissions within that band to a level at least 10 dB below the applicable part 15 limits.
(iii) At locations where an Access BPL operator attenuates radiated emissions from its operations in accordance with the above required capabilities, we will not require that operator to take further actions to resolve complaints of harmful interference to mobile operations.
(2) Access BPL systems shall comply with applicable radiated emission limits upon power-up following a fault condition, or during a start-up operation after a shut-off procedure, by the use of a non-volatile memory, or some other method, to immediately restore previous settings with programmed notches and excluded bands, to avoid time delay caused by the need for manual re-programming during which protected services may be vulnerable.
(3) Access BPL systems shall incorporate a remote-controllable shut-down feature to deactivate, from a central location, any unit found to cause harmful interference, if other interference mitigation techniques do not resolve the interference problem.
Compliance measurements for Access BPL shall be made in accordance with the Guidelines for Access BPL systems specified by the Commission.
(a) Access BPL Database. Entities operating Access BPL systems shall supply to an industry-recognized entity, information on all existing Access BPL systems and all proposed Access BPL systems for inclusion into a publicly available data base, within 30 days prior to initiation of service. Such information shall include the following:
(1) The name of the Access BPL provider.
(2) The frequencies of the Access BPL operation.
(3) The postal zip codes served by the specific Access BPL operation.
(4) The manufacturer and type of Access BPL equipment and its associated FCC ID number, or, in the case of Access BPL equipment that has not been subject to certification in the past, the Trade Name and Model Number, as specified on the equipment label.
(5) The contact information, including both phone number and e-mail address of a person at, or associated with, the BPL operator's company, to facilitate the resolution of any interference complaint.
(6) The proposed/or actual date of Access BPL operation.
(b) The Access BPL database manager shall enter this information into the publicly accessible database within three (3) business days of receipt.
(c) No notification to the Commission is required.
(d) A licensed spectrum user experiencing harmful interference that is suspected to be caused by an Access BPL system shall inform the local BPL operator's contact person designated in the Access BPL database. The investigation of the reported interference and the resolution of confirmed harmful interference from the Access BPL system shall be successfully completed by the BPL operator within a reasonable time period according to a mutually acceptable schedule, after the receipt of an interference complaint, in order to avoid protracted disruptions to licensed services. The Access BPL operator shall respond to complaints of harmful interference from public safety users within 24 hours. With regard to public safety complaints, the BPL provider shall be required to immediately cease the operations causing such complaint if it fails to respond within 24 hours.
(e) Consultation with public safety users. An entity operating an Access BPL system shall notify and consult with the public safety users in the area where it plans to deploy Access BPL, at least 30 days prior to initiation of any operation or service. This entity shall design or implement the Access BPL system such that it does not cause harmful interference in those frequencies or bands used by the public safety agencies in the area served by the Access BPL system. The notification shall include, at a minimum, the information in paragraph (a) of this section.
(f) Federal government spectrum users and other radio service users. An entity operating an Access BPL system shall ensure that, within its Access BPL deployment area, its system does not operate on any frequencies designated as excluded bands or on identified frequencies within any designated exclusion zones.
(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) Exclusion zones. Exclusion zones encompass the operation of any Access BPL system within 1km of the boundary of coast station facilities at the coordinates listed in Tables 2 and 2.1. Exclusion zones also encompass the operation of Access BPL systems using overhead medium voltage power lines within 65 km of the Very Large Array observatory located at the coordinate 34°04′43.50″; N, 107°37′03.82″ W. Exclusion zones further encompass the operation of Access BPL systems using overhead low voltage power lines or underground power lines within 47 km of the Very Large Array observatory located at the coordinate 34°04′43.50″; N, 107°37′03.82″ W. Within the exclusion zones for coast stations, Access BPL systems shall not use carrier frequencies within the band of 2173.5-2190.5 kHz. Within the exclusion zone for the Very Large Array radio astronomy observatory, Access BPL systems shall not use carrier frequencies within the 73.0-74.6 MHz band.
(i) Existing coast station facilities. Access BPL systems shall not operate in the frequency band 2,173.5-2,190.5 kHz, within 1 kilometer (km) of the boundary of coast station facilities at the coordinates listed in Tables 2 and 2.1. BPL operators planning to deploy Access BPL devices at these frequencies in areas within these exclusion zones as defined above shall consult with the appropriate point of contact for these coast stations to ensure harmful interference is prevented at these facilities.
Point of contact: Commandant (CG 622), U.S. Coast Guard, 2100 2nd Street, SW., Washington, DC 20593-0001, Telephone: (202) 267-2860, e-mail: email@example.com.
Table 2 - Exclusion Zones for U.S. Coast Guard Coast Stations
|Group Guam||13°35′23″ N||144°50′24″ E|
|GANTSEC||18°18′00″ N||65°46′59″ W|
|Puerto Rico||18°28′11″ N||66°07′47″ W|
|Honolulu||21°18′21″ N||157°53′23″ W|
|Group Key West||24°33′35″ N||81°47′59″ W|
|Trumbo Point CG Base||24°33′58″ N||81°47′57″ W|
|Miami||25°37′28″ N||80°23′07″ W|
|Everglades Park||25°50′10″ N||81°23′13″ W|
|Group Saint Petersburg (Everglades)||25°51′00″ N||81°23′24″ W|
|Station Ft. Lauderdale||26°05′21″ N||80°06′40″ W|
|Station Ft. Myers Beach||26°27′34″ N||81°57′15″ W|
|Group Miami (Ft. Pierce)||27°27′36″ N||80°18′36″ W|
|Station Ft. Pierce||27°27′50″ N||80°18′27″ W|
|Group Corpus Christi||27°42′01″ N||97°16′11″ W|
|Group Corpus Christi||27°42′06″ N||97°16′45″ W|
|ESD Saint Petersburg||27°45′21″ N||82°37′32″ W|
|Group Saint Petersburg||27°46′11″ N||82°37′47″ W|
|Station Port O'Connor||28°26′03″ N||96°25′39″ W|
|S. Padre Island||28°26′22″ N||97°09′56″ W|
|Freeport||28°55′59″ N||95°16′59″ W|
|Group Galveston (Freeport)||28°56′24″ N||95°17′59″ W|
|Station YANKEETOWN||29°01′51″ N||82°43′39″ W|
|Station Ponce De Leon Inlet||29°03′50″ N||81°55′01″ W|
|Group New Orleans (Grand Isle)||29°15′53″ N||89°57′26″ W|
|Galveston||29°19′59″ N||94°46′18″ W|
|Kapalan||29°20′04″ N||94°47′17″ W|
|Sabine||29°43′42″ N||93°52′14″ W|
|New Orleans||30°01′17″ N||90°07′24″ W|
|Panama City||30°10′01″ N||85°45′04″ W|
|Group Mobile (Panama City)||30°10′12″ N||85°45′36″ W|
|ANT Jacksonville Beach||30°17′16″ N||81°24′10″ W|
|Pensacola||30°20′24″ N||87°18′17″ W|
|Group Mayport||30°23′10″ N||81°26′01″ W|
|Group Mayport||30°23′24″ N||81°25′48″ W|
|Ft. Morgan||30°39′07″ N||88°03′12″ W|
|Tybee Lighthouse||32°01′15″ N||80°50′39″ W|
|Point Loma Lighthouse||32°39′56″ N||117°14′34″ W|
|Point Loma||32°40′07″ N||117°14′14″ W|
|Activities San Diego||32°43′59″ N||117°11′13″ W|
|Group Charleston (Sullivan's Island)||32°45′00″ N||79°49′47″ W|
|Sullivan's Island Lights||32°45′02″ N||79°50′03″ W|
|Group Charleston||32°46′25″ N||79°56′37″ W|
|Group San Diego||32°52′48″ N||118°26′23″ W|
|San Pedro||33°45′00″ N||118°15′58″ W|
|Group Fort Macon||33°53′24″ N||78°01′48″ W|
|Point Mugu||33°59′32″ N||119°07′18″ W|
|Group LA/Long Beach||34°07′11″ N||119°06′35″ W|
|Channel Island||34°09′17″ N||119°13′11″ W|
|Station Oxnard Channel Island||34°09′43″ N||119°13′19″ W|
|Group Ft. Macon||34°41′48″ N||76°40′59″ W|
|Group Cape Hatteras||35°13′59″ N||75°31′59″ W|
|Group Cape Hatteras||35°15′35″ N||75°31′48″ W|
|Morro Bay (Cambria)||35°31′21″ N||121°03′31″ W|
|San Clemente Island||32°50′24″ N||118°23′15″ W|
|Point Pinos||36°38′12″ N||121°56′06″ W|
|CAMSLANT||36°43′47″ N||76°01′11″ W|
|Group Hampton Roads||36°53′01″ N||76°21′10″ W|
|Point Montara||37°31′23″ N||122°30′47″ W|
|Point Montara Lighthouse||37°32′09″ N||122°31′08″ W|
|Group San Francisco||37°32′23″ N||122°31′11″ W|
|Group San Francisco||37°48′34″ N||122°21′55″ W|
|Point Bonita||37°49′00″ N||122°31′41″ W|
|Group Eastern Shores||37°55′47″ N||75°22′47″ W|
|Group Eastern Shore||37°55′50″ N||75°22′58″ W|
|CAMSPAC||38°06′00″ N||122°55′48″ W|
|Point Arena Lighthouse||38°57′18″ N||124°44′28″ W|
|Point Arena||38°57′36″ N||123°44′23″ W|
|Group Atlantic City||39°20′59″ N||74°27′42″ W|
|Activities New York||40°36′06″ N||74°03′36″ W|
|Activities New York||40°37′11″ N||74°04′11″ W|
|ESD Moriches Hut||40°47′19″ N||72°44′53″ W|
|Group Moriches||40°47′23″ N||72°45′00″ W|
|Group Humboldt Bay||40°58′41″ N||124°06′31″ W|
|Group Humboldt Bay||40°58′47″ N||124°06′35″ W|
|Trinidad Head||41°03′15″ N||124°09′02″ W|
|Group Long Island Sound||41°16′12″ N||72°54′00″ W|
|Station New Haven||41°16′12″ N||72°54′06″ W|
|Station Brant Point||41°17′21″ N||70°05′31″ W|
|Group Woods Hole||41°17′23″ N||70°04′47″ W|
|Station Castle Hill||41°27′46″ N||71°21′42″ W|
|Group Woods Hole||41°17′29″ N||70°401′07″ W|
|Boston Area||41°40′12″ N||70°31′48″ W|
|Station Provincetown||42°01′48″ N||70°12′42″ W|
|Eastern Point||42°36′24″ N||70°39′26″ W|
|Cape Blanco||42°50′16″ N||124°33′52″ W|
|Group North Bend||43°24′16″ N||124°13′22″ W|
|Group North Bend||43°24′35″ N||124°14′23″ W|
|Cape Elizabeth||43°33′28″ N||70°12′00″ W|
|Group South Portland||43°38′24″ N||70°15′00″ W|
|Group South Portland||43°38′45″ N||70°14′51″ W|
|Group SW Harbor||44°16′19″ N||68°18′27″ W|
|Group Southwest Harbor||44°16′48″ N||68°18′36″ W|
|Fort Stevens, Oregon||46°09′14″ N||123°53′07″ W|
|Group Astoria||46°09′29″ N||123°31′48″ W|
|Group Astoria||46°09′35″ N||123°53′24″ W|
|La Push||47°49′00″ N||124°37′59″ W|
|Station Quillayute River||47°54′49″ N||124°38′01″ W|
|Port Angeles||48°07′59″ N||123°25′59″ W|
|Group Port Angeles||48°08′24″ N||123°24′35″ W|
|Juneau (Sitka)||57°05′24″ N||135°15′35″ W|
|Kodiak||57°40′47″ N||152°28′47″ W|
|Valdez (Cape Hinchinbrook)||60°26′23″ N||146°25′48″ W|
Table 2.1 - Exclusion Zones for Maritime Public Coast Stations
[Points of Contact Are Identified in the Commission's License Database]
|Shipcom LLC||Marina Del Ray, CA||33°56′21″ N||118°27′14″ W|
|Globe Wireless||Rio Vista, CA||38°11′55″ N||121°48′34″ W|
|Avalon Communications Corp||St. Thomas, VI||18°21′19″ N||64°56′48″ W|
|Globe Wireless||Bishopville, MD||38°24′10″ N||75°12′59″ W|
|Shipcom LLC||Mobile, AL||30°40′07″ N||88°10′23″ W|
|Shipcom LLC||Coden, AL||30°22′35″ N||88°12′20″ W|
|Globe Wireless||Pearl River, LA||30°22′13″ N||89°47′26″ W|
|Globe Wireless||Kahalelani, HI||21°10′33″ N||157°10′39″ W|
|Globe Wireless||Palo Alto, CA||37°26′44″ N||122°06′48″ W|
|Globe Wireless||Agana, GU||13°29′22″ N||144°49′39″ E|
(ii) New or relocated Coast stations. In the unlikely event that a new or relocated coast station is established for the 2.173.5-2.190.5 kHz band at a coordinate not specified in Table 2 or 2.1, Access BPL operations in that frequency band shall also be excluded within 1 km of the new coast station facility;
(3) Consultation areas. Access BPL operators shall provide notification to the appropriate point of contact specified regarding Access BPL operations at any frequencies of potential concern in the following consultation areas, at least 30 days prior to initiation of any operation or service. The notification shall include, at a minimum, the information in paragraph (a) of this section. We expect parties to consult in good faith to ensure that no harmful interference is caused to licensed operations and that any constraints on BPL deployments are minimized to those necessary to avoid harmful interference. In the unlikely event that a new or relocated aeronautical receive station is established for the 1.7-30 MHz band at a coordinate not specified in Table 3b, Access BPL operators are also required to coordinate with the appropriate point of contact regarding Access BPL operations at any frequencies of potential concern in the new or relocated consultation areas, and to adjust their system operating parameters to protect the new or relocated aeronautical receive station.
(i) For frequencies in the 1.7-30 MHz frequency range, the areas within 4 km of facilities located at the following coordinates:
(A) The Commission's protected field offices listed in 47 CFR 0.121, the point-of-contact for which is specified in that section;
(B) The aeronautical stations listed in Tables 3a and 3b;
(C) The land stations listed in Tables 4 and 5;
(ii) For frequencies in the 1.7-80.0 MHz frequency range, the areas within 4 km of facilities located at the coordinates specified for radio astronomy facilities in 47 CFR 2.106, Note U.S. 311.
Point of contact: Electromagnetic Spectrum Manager, National Science Foundation, Division of Astronomical Sciences, 4201 Wilson Blvd., Suite 1045, Arlington, VA 22230, (703) 292-4896, firstname.lastname@example.org.
(iii) For frequencies in the 1.7-80 MHz frequency range, the area within 1 km of the Table Mountain Radio Receiving Zone, the coordinates and point of contact for which are specified in 47 CFR 21.113(b).
(iv) For frequencies in the 1.7-30 MHz frequency range, the areas within 37 km of radar receiver facilities located at the coordinates specified in Table 6.
Table 3a - Consultation Area Coordinates for Aeronautical (OR) Stations (1.7-30 MHz)
|Washington||Arlington, VA||38°51′07″ N||77°02′15″ W|
|Cape Cod||Cape Cod, MA||41°42′00″ N||70°30′00″ W|
|Atlantic City||Atlantic City, NJ||39°20′59″ N||74°27′42″ W|
|Elizabeth City||Elizabeth City, NC||36°15′53″ N||76°10′32″ W|
|Savannah||Savannah, GA||32°01′30″ N||81°08′30″ W|
|Miami||Opa Locka, FL||25°54′22″ N||80°16′01″ W|
|Clearwater||Clearwater, FL||27°54′27″ N||82°41′29″ W|
|Borinquen||Aguadilla, PR||18°18′36″ N||67°04′48″ W|
|New Orleans||New Orleans, LA||29°49′31″ N||90°02′06″ W|
|Traverse City||Traverse City, MI||44°44′24″ N||85°34′54″ W|
|San Diego||San Diego, CA||32°43′33″ N||117°10′15″ W|
|Sacramento||McCllelan AFB, CA||38°40′06″ N||121°24′04″ W|
|Astoria||Warrenton, OR||46°25′18″ N||123°47′46″ W|
|North Bend||North Bend, OR||43°24′39″ N||124°14′35″ W|
|Barbers Point||Kapolei, HI||21°18′01″ N||158°04′15″ W|
|Kodiak||Kodiak, AK||57°44′19″ N||152°30′18″ W|
|Houston||Houston, TX||29°45′00″ N||95°22′00″ W|
|Detroit||Mt. Clemens, MI||42°36′05″ N||82°50′12″ W|
|San Francisco||San Francisco, CA||37°37′58″ N||122°23′20″ W|
|Los Angeles||Los Angeles, CA||33°56′36″ N||118°23′48″ W|
|Humboldt Bay||McKinleyville, CA||40°58′39″ N||124°06′45″ W|
|Port Angeles||Port Angeles, WA||48°08′25″ N||123°24′48″ W|
|Sitka||Sitka, AK||57°05′50″ N||135°21′58″ W|
Table 3b - Consultation Area Coordinates for Aeronautical Receive Stations (1.7-30 MHz)
|Southampton, NY||40°55′15″ N||72°23′41″ W|
|Molokai, HI||21°12′23″ N||157°12′30″ W|
|Oahu, HI||21°22′27″ N||158°05′56″ W|
|Half Moon Bay, CA||37°39′64″ N||122°24′44″ W|
|Pt. Reyes, CA||38°06′00″ N||122°56′00″ W|
|Barrow, AK||71°17′24″ N||156°40′12″; W|
|Guam||13°28′12″ N||144°48′0.0″ E (note: Eastern Hemisphere)|
|NY Comm Center, NY||40°46′48″ N||73°05′46″ W|
|Cedar Rapids, IA||42°02′05.0″ N||91°38′37.6″ W|
|Beaumont, CA||33°54′27.1″ N||116°59′49.1″ W|
|Fairfield, TX||31°47′02.6″ N||96°47′03.0″ W|
|Houston, TX||29°36′35.8″ N||95°16′54.8″ W|
|Miami, FL||25°49′05″ N||80°18′28″ W|
Table 4 - Consultation Area Coordinates for Land Stations, Set 1 (1.7-30 MHz)
|COMMSTA Boston||Maspee, MA||41°24′00″ N||70°18′57″ W|
|Camslant||Chesapeake, VA||36°33′59″ N||76°15′23″ W|
|COMMSTA Miami||Miami, FL||25°36′58″ N||80°23′04″ W|
|COMMSTA New Orleans||Belle Chasse, IA||29°52′40″ N||89°54′46″ W|
|Camspac||Pt. Reyes Sta, CA||38°06′00″ N||122°55′48″ W|
|COMMSTA Honolulu||Wahiawa, HI||21°31′08″ N||157°59′28″ W|
|COMMSTA Kodiak||Kodiak, AK||57°04′26′ N||152°28′20″ W|
|Guam||Finegayan, GU||13°53′08″ N||144°50′20″ E|
Table 5 - Consultation Area Coordinates for Land Stations, Set 2 (1.7-30 MHz)
|Albuquerque, NM||35°05′02″ N||105°34′23″ W|
|Arecibo, PR||18°17′26″ N||66°22′33″ W|
|Atlanta, GA||32°33″06 N||84°23′35″ W|
|Beaufort, SC||34°34′22″ N||76°09′48″ W|
|Cape Charles, VA||37°05′37″ N||75°58′06″ W|
|Cedar Rapids, IA||42°00′09″ N||91°17′39″ W|
|Denver, CO||39°15′45″ N||103°34′23″ W|
|Fort Myers, FL||81°31′20″ N||26°20′01″ W|
|Kansas City, MO||38°22′10″ N||93°21′48″ W|
|Las Vegas, NV||36°21′15″ N||114°17′33″ W|
|Lovelock, NV||40°03′07″ N||118°18′56″ W|
|Memphis, TN||34°21′57″ N||90°02′43″ W|
|Miami, FL||25°46′20″ N||80°28′48″ W|
|Morehead City, NC||34°34′50″ N||78°13′59″ W|
|Oklahoma City, OK||34°30′52″ N||97°30′52″ W|
|Orlando, FL||28°31′30″ N||80°48′58″ W|
|Reno, NV||38°31′12″ N||119°14′37″ W|
|Sarasota, FL||27°12′41″ N||81°31′20″ W|
|Wilmington, NC||34°29′24″ N||78°04′31″ W|
Point of contact: U.S. Coast Guard HQ, Division of Spectrum Management CG-622, 2100 Second St., SW., Rm. 6611, Washington, DC 20593, Tel: (202) 267-6036, Fax: (202) 267-4106, e-mail: email@example.com.
Point of contact: U.S. Coast Guard HQ, Division of Spectrum Management CG-622, 2100 Second St., SW., Rm. 6611, Washington, DC 20593, Tel: (202) 267-6036, Fax: (202) 267-4106, e-mail: firstname.lastname@example.org.
Point of contact: COTHEN Technical Support Center, COTHEN Program Manager, Tel: (800) 829-6336.
Point Of Contact: ROTHR Deputy Program Manager, (540) 653-3624.
Table 6 - Consultation Area Coordinates for Radar Receiver Stations (1.7-30 MHz)
|18°01′ N/66°30′ W|
|28°05′ N/98°43′ W|
|36°34′ N/76°18′ W|