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E1F04

COMMISSION RULES · Miscellaneous rules: external RF power amplifiers; prohibited communications; spread spectrum; auxiliary stations; Canadian amateurs operating in the US; special temporary authority

E1F04§ 97.3E1F →

Which of the following geographic descriptions approximately describes "Line A"?

  1. AA line roughly parallel to and south of the border between the US and Canada
  2. BA line roughly parallel to and west of the US Atlantic coastline
  3. CA line roughly parallel to and north of the border between the US and Mexico
  4. DA line roughly parallel to and east of the US Pacific coastline
Why Line A is defined in Part 97.3 as a line running roughly parallel to and about 50 miles south of the US-Canada border, from Washington state eastward. Its purpose is protecting Canadian land mobile services: stations north of Line A may not transmit in the 420-430 MHz segment of the 70 cm band. So if you live in the northern tier of states, 420-430 MHz is off limits unless you are south of that line.
Watch out The choice about the US-Mexico border is the usual trap, but there is no corresponding Line A there; the 420-430 MHz restriction is a Canadian coordination issue, not a Mexican one.
Line A = Above us is Canada. About 50 miles south of the Canadian border, no 420-430 MHz north of it.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
47 CFR 97.3 Definitions.

(a) The definitions of terms used in part 97 are:

(1) Amateur operator. A person named in an amateur operator/primary license station grant on the ULS consolidated licensee database to be the control operator of an amateur station.

(2) Amateur radio services. The amateur service, the amateur-satellite service and the radio amateur civil emergency service.

(4) Amateur service. A radiocommunication service for the purpose of self-training, intercommunication and technical investigations carried out by amateurs, that is, duly authorized persons interested in radio technique solely with a personal aim and without pecuniary interest.

(5) Amateur station. A station in an amateur radio service consisting of the apparatus necessary for carrying on radiocommunications.

(6) Automatic control. The use of devices and procedures for control of a station when it is transmitting so that compliance with the FCC Rules is achieved without the control operator being present at a control point.

(7) Auxiliary station. An amateur station, other than in a message forwarding system, that is transmitting communications point-to-point within a system of cooperating amateur stations.

(8) Bandwidth. The width of a frequency band outside of which the mean power of the transmitted signal is attenuated at least 26 dB below the mean power of the transmitted signal within the band.

(9) Beacon. An amateur station transmitting communications for the purposes of observation of propagation and reception or other related experimental activities.

(10) Broadcasting. Transmissions intended for reception by the general public, either direct or relayed.

(11) Call sign system. The method used to select a call sign for amateur station over-the-air identification purposes. The call sign systems are:

(i) Sequential call sign system. The call sign is selected by the FCC from an alphabetized list corresponding to the geographic region of the licensee's mailing address and operator class. The call sign is shown on the license. The FCC will issue public announcements detailing the procedures of the sequential call sign system.

(ii) Vanity call sign system. The call sign is selected by the FCC from a list of call signs requested by the licensee. The call sign is shown on the license. The FCC will issue public announcements detailing the procedures of the vanity call sign system.

(iii) Special event call sign system. The call sign is selected by the station licensee from a list of call signs shown on a common data base coordinated, maintained and disseminated by the amateur station special event call sign data base coordinators. The call sign must have the single letter prefix K, N or W, followed by a single numeral 0 through 9, followed by a single letter A through W or Y or Z (for example K1A). The special event call sign is substituted for the call sign shown on the station license grant while the station is transmitting. The FCC will issue public announcements detailing the procedures of the special event call sign system.

(12) CEPT radio amateur license. A license issued by a country belonging to the European Conference of Postal and Telecommunications Administrations (CEPT) that has adopted Recommendation T/R 61-01 (Nice 1985, Paris 1992, Nicosia 2003).

(13) Control operator. An amateur operator designated by the licensee of a station to be responsible for the transmissions from that station to assure compliance with the FCC Rules.

(14) Control point. The location at which the control operator function is performed.

(15) CSCE. Certificate of successful completion of an examination.

(16) Earth station. An amateur station located on, or within 50 km of, the Earth's surface intended for communications with space stations or with other Earth stations by means of one or more other objects in space.

(17) [Reserved]

(18) External RF power amplifier. A device capable of increasing power output when used in conjunction with, but not an integral part of, a transmitter.

(19) [Reserved]

(20) FAA. Federal Aviation Administration.

(21) FCC. Federal Communications Commission.

(22) Frequency coordinator. An entity, recognized in a local or regional area by amateur operators whose stations are eligible to be auxiliary or repeater stations, that recommends transmit/receive channels and associated operating and technical parameters for such stations in order to avoid or minimize potential interference.

(23) Harmful interference. Interference which endangers the functioning of a radionavigation service or of other safety services or seriously degrades, obstructs or repeatedly interrupts a radiocommunication service operating in accordance with the Radio Regulations.

(24) IARP (International Amateur Radio Permit). A document issued pursuant to the terms of the Inter-American Convention on an International Amateur Radio Permit by a country signatory to that Convention, other than the United States. Montrouis, Haiti. AG/doc.3216/95.

(25) Indicator. Words, letters or numerals appended to and separated from the call sign during the station identification.

(26) Information bulletin. A message directed only to amateur operators consisting solely of subject matter of direct interest to the amateur service.

(27) In-law. A parent, stepparent, sibling, or step-sibling of a licensee's spouse; the spouse of a licensee's sibling, step-sibling, child, or stepchild; or the spouse of a licensee's spouse's sibling or step-sibling.

(28) International Morse code. A dot-dash code as defined in ITU-T Recommendation F.1 (March, 1998), Division B, I. Morse code.

(29) ITU. International Telecommunication Union.

(30) Line A. Begins at Aberdeen, WA, running by great circle arc to the intersection of 48° N, 120° W, thence along parallel 48° N, to the intersection of 95° W, thence by great circle arc through the southernmost point of Duluth, MN, thence by great circle arc to 45° N, 85° W, thence southward along meridian 85° W, to its intersection with parallel 41° N, thence along parallel 41° N, to its intersection with meridian 82° W, thence by great circle arc through the southernmost point of Bangor, ME, thence by great circle arc through the southernmost point of Searsport, ME, at which point it terminates.

(31) Local control. The use of a control operator who directly manipulates the operating adjustments in the station to achieve compliance with the FCC Rules.

(32) Message forwarding system. A group of amateur stations participating in a voluntary, cooperative, interactive arrangement where communications are sent from the control operator of an originating station to the control operator of one or more destination stations by one or more forwarding stations.

(33) National Radio Quiet Zone. The area in Maryland, Virginia and West Virginia Bounded by 39°15′ N on the north, 78°30′ W on the east, 37°30′ N on the south and 80°30′ W on the west.

(34) Physician. For the purpose of this part, a person who is licensed to practice in a place where the amateur service is regulated by the FCC, as either a Doctor of Medicine (M.D.) or a Doctor of Osteopathy (D.O.)

(35) Question pool. All current examination questions for a designated written examination element.

(36) Question set. A series of examination questions on a given examination selected from the question pool.

(37) Radio Regulations. The latest ITU Radio Regulations to which the United States is a party.

(38) RACES (radio amateur civil emergency service). A radio service using amateur stations for civil defense communications during periods of local, regional or national civil emergencies.

(39) Remote control. The use of a control operator who indirectly manipulates the operating adjustments in the station through a control link to achieve compliance with the FCC Rules.

(40) Repeater. An amateur station that simultaneously retransmits the transmission of another amateur station on a different channel or channels.

(41) Space station. An amateur station located more than 50 km above the Earth's surface.

(42) Space telemetry. A one-way transmission from a space station of measurements made from the measuring instruments in a spacecraft, including those relating to the functioning of the spacecraft.

(43) Spurious emission. An emission, or frequencies outside the necessary bandwidth of a transmission, the level of which may be reduced without affecting the information being transmitted.

(44) Telecommand. A one-way transmission to initiate, modify, or terminate functions of a device at a distance.

(45) Telecommand station. An amateur station that transmits communications to initiate, modify or terminate functions of a space station.

(46) Telemetry. A one-way transmission of measurements at a distance from the measuring instrument.

(47) Third party communications. A message from the control operator (first party) of an amateur station to another amateur station control operator (second party) on behalf of another person (third party).

(48) ULS (Universal Licensing System). The consolidated database, application filing system and processing system for all Wireless Telecommunications Services.

(49) VE. Volunteer examiner.

(50) VEC. Volunteer-examiner coordinator.

(b) The definitions of technical symbols used in this part are:

(1) EHF (extremely high frequency). The frequency range 30-300 GHz.

(2) EIRP (equivalent isotropically radiated power). The product of the power supplied to the antenna and the antenna gain in a given direction relative to an isotropic antenna (absolute or isotropic gain).

Divide EIRP by 1.64 to convert to effective radiated power.

(3) ERP (effective radiated power) (in a given direction). The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction.

Multiply ERP by 1.64 to convert to equivalent isotropically radiated power.

(4) HF (high frequency). The frequency range 3-30 MHz.

(5) Hz. Hertz.

(6) LF (low frequency). The frequency range 30-300 kHz.

(7) m. Meters.

(8) MF (medium frequency). The frequency range 300-3000 kHz.

(9) PEP (peak envelope power). The average power supplied to the antenna transmission line by a transmitter during one RF cycle at the crest of the modulation envelope taken under normal operating conditions.

(10) RF. Radio frequency.

(11) SHF (super high frequency). The frequency range 3-30 GHz.

(12) UHF (ultra high frequency). The frequency range 300-3000 MHz.

(13) VHF (very high frequency). The frequency range 30-300 MHz.

(14) W. Watts.

(c) The following terms are used in this part to indicate emission types. Refer to § 2.201 of the FCC Rules, Emission, modulation and transmission characteristics, for information on emission type designators.

(1) CW. International Morse code telegraphy emissions having designators with A, C, H, J or R as the first symbol; 1 as the second symbol; A or B as the third symbol; and emissions J2A and J2B.

(2) Data. Telemetry, telecommand and computer communications emissions having (i) designators with A, C, D, F, G, H, J or R as the first symbol, 1 as the second symbol, and D as the third symbol; (ii) emission J2D; and (iii) emissions A1C, F1C, F2C, J2C, and J3C having an occupied bandwidth of 500 Hz or less when transmitted on an amateur service frequency below 30 MHz. Only a digital code of a type specifically authorized in this part may be transmitted.

(3) Image. Facsimile and television emissions having designators with A, C, D, F, G, H, J or R as the first symbol; 1, 2 or 3 as the second symbol; C or F as the third symbol; and emissions having B as the first symbol; 7, 8 or 9 as the second symbol; W as the third symbol.

(4) MCW. Tone-modulated international Morse code telegraphy emissions having designators with A, C, D, F, G, H or R as the first symbol; 2 as the second symbol; A or B as the third symbol.

(5) Phone. Speech and other sound emissions having designators with A, C, D, F, G, H, J or R as the first symbol; 1, 2, 3 or X as the second symbol; E as the third symbol. Also speech emissions having B or F as the first symbol; 7, 8 or 9 as the second symbol; E as the third symbol. MCW for the purpose of performing the station identification procedure, or for providing telegraphy practice interspersed with speech. Incidental tones for the purpose of selective calling or alerting or to control the level of a demodulated signal may also be considered phone.

(6) Pulse. Emissions having designators with K, L, M, P, Q, V or W as the first symbol; 0, 1, 2, 3, 7, 8, 9 or X as the second symbol; A, B, C, D, E, F, N, W or X as the third symbol.

(7) RTTY. Narrow-band direct-printing telegraphy emissions having designators with A, C, D, F, G, H, J or R as the first symbol; 1 as the second symbol; B as the third symbol; and emission J2B. Only a digital code of a type specifically authorized in this part may be transmitted.

(8) SS. Spread spectrum emissions using bandwidth-expansion modulation emissions having designators with A, C, D, F, G, H, J or R as the first symbol; X as the second symbol; X as the third symbol.

(9) Test. Emissions containing no information having the designators with N as the third symbol. Test does not include pulse emissions with no information or modulation unless pulse emissions are also authorized in the frequency band.

eCFR text as of 1 Sep 2026 · read on ecfr.gov
← E1F03 All of E1F E1F05 →

The rest of E1F

  1. E1F01 On what frequencies are spread spectrum transmissions permitted?
  2. E1F02 What privileges are authorized in the US to persons holding an amateur service license granted by the governm…
  3. E1F03 Under what circumstances may a dealer sell an external RF power amplifier capable of operation below 144 MHz …
  4. E1F04 Which of the following geographic descriptions approximately describes "Line A"?
  5. E1F05 Amateur stations may not transmit in which of the following frequency segments if they are located in the con…
  6. E1F06 Under what circumstances might the FCC issue a Special Temporary Authority (STA) to an amateur station?
  7. E1F07 When may an amateur station send a message to a business?
  8. E1F08 Which of the following types of amateur station communications are prohibited?
  9. E1F09 Which of the following cannot be transmitted over an amateur radio mesh network?
  10. E1F10 Who may be the control operator of an auxiliary station?
  11. E1F11 Which of the following best describes one of the standards that must be met by an external RF power amplifier…
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