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Part 97 Of The FCC Rules
John B. Johnston W3BE
These are the terms that must be understood in order to make meaningful
Part 97 of the FCC rules for our amateur services.
AM (amplitude modulation) A method for transmitting information by varying the strength of the transmitted
signal in relation to the information being sent. The result is a carrier, along with sideband signals on frequencies slightly
above (upper sideband) and below (lower sideband), being transmitted. Each sideband is a mirror image of the other and is
equal in bandwidth to that of the modulating signal.
AMTOR The 7-unit code specified in ITU-R Recommendations M.476-5 and M.625-3.
angle-modulated emission Where the frequency
or phase of the carrier wave varies in proportion to the amplitude of the modulating signal.
antenna gain A performance figure combining an antenna's
directivity and electrical efficiency.
directivity A measure of the power density radiated in the direction of its strongest emission, versus the power
density radiated by a isotropic radiator radiating the same total power.
ASCII The 7-unit International Alphabet No. 5 code defined in ITU-T Recommendation
T.50 (commonly known as "ASCII").
Where desired actions occur without intervention by the control operator.
band A defined range of contiguous frequencies.
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.
A unit of signaling speed equal to the number of discrete conditions or events per second.
Baudot The 5-unit, start-stop, International Telegraph Alphabet No.
2, code defined in ITU-T Recommendation F.1, Division C.
carrier Usually the number appearing on a transceiver’s frequency display. It
is the frequency with which a transmitted signal is compared during the de-modulation process in a receiver. It is generated
in either the transmitter (AM) or in the receiver (SSB). It can designate the nominal frequency of a carrier wave; the center
frequency of an FM signal; the frequency of the un-modulated electrical wave at the output of an AM, FM, or PM transmitter;
or the output of a transmitter when the modulation is zero.
channel A band of frequencies of sufficient width for
a single radio communication.
radiation Unwanted electromagnetic energy radiated directly from the internal circuitry of an electronic apparatus.
CLOVER A certain digital code whose technical
characteristics have been documented publicly.
cm (centimeter) A length of approximately 0.3937 inches.
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.
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
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 Part 97 may be transmitted.
dB (decibel) An expression
of power gains and losses. Ten times the logarithm to the base ten of the ratio of two power levels.
dBd Decibel gain over a dipole antenna.
dipole An antenna with two elements in
a straight line that are fed RF energy in its center.
e.r.p. (effective radiated power) The transmitter PEP multiplied by
the antenna gain relative to a half-wave dipole antenna. A half-wave dipole antenna is presumed to have a gain of 1 (0
electromagnetic field Energy
moving through space or materials in the form of changing electric and magnetic fields.
emission Electromagnetic radiation from
an antenna; also refers to modulation type, sometimes called mode, i.e., CW, MCW, phone, image, data, RTTY, pulse, SS and
external RF power amplifier
A device capable of increasing power output when used in conjunction with, but not an integral part of, a transmitter.
external RF power amplifier kit
A number of electronic parts, which, when assembled, is an external RF power amplifier, even if additional parts are required
to complete assembly.
(Extremely high frequency) The frequency range 30-300 GHz.
frequency The number of complete oscillations per
second of energy (as sound or electromagnetic radiation) in the form of waves.
frequency shift keying A method of digital modulation in which individual
bit values are represented by specific frequencies.
The voltage or signal intensity increase caused by an amplifier or directional antenna.
GHz (gigahertz) 1,000,000,000 Hz.
G-TOR A digital code for the purpose of
facilitating communications whose technical characteristics have been documented publicly.
harmful interference RF 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 latest ITU Radio Regulations to which the United States is a party.
HF (High frequency) The frequency range
Hz (Hertz) The unit
for expressing frequency. One Hertz equals one cycle per second.
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.
isotropically radiated power The power density radiated by an antenna that propagates uniformly
in all directions.
The number of bits that are conveyed or processed per unit of time.
keyclick A spurious emission resulting from telegraphy keying.
kilobaud 1,000 baud.
km (kilometer) A distance of approximately 0.621371 miles.
m (meter) A length of approximately 39.37
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.
power The average power supplied to the antenna transmission line by a transmitter during an interval of time sufficiently
long compared with the lowest frequency encountered in the modulation taken under normal operating conditions.
MF (medium frequency) The frequency range
300-3000 kHz. 97.3(b)(5)
(megahertz) 1,000,000 Hz.
A length of approximately 0.0394 inches.
The process of varying the amplitude, frequency, or phase of a radio wave for the transmission
An indicator of how much the modulated variable of a carrier signal varies around its un-modulated level.
modulation frequency The frequency used to modulate the carrier
during the modulation process.
combining of many signals into a single transmission circuit or channel.
nautical mile An international unit equal to 1852
meters. 6076.115 feet or 1.15 statute miles.
PacTOR A digital code for the purpose of facilitating communications whose technical characteristics
have been documented publicly.
(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.
phone Speech and other sound 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; E as the third symbol. Also speech emissions having
B 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.
power line radiation Unwanted
electromagnetic energy radiated from the wiring that delivers electrical power.
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. )
RF (radio frequency) The rate of oscillation in the range of about
3 kHz to 300 GHz.
RF power amplifier
A radio station device that raises the power level of a radio signal during transmission.
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.
segment A portion of a frequency band.
SHF (Super-high frequency) The frequency
range 3-30 GHz.
of an RF signal generated as part of the modulation process.
SSB (single sideband) The one of two AM sidebands that is unsuppressed, along with the carrier,
Spurious RF emissions in an overly broad transmitted signal.
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.
spurious emission An RF emission
on frequencies outside the necessary bandwidth of a transmission, the level of which may be reduced without affecting the
information being transmitted.
(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.
telecommand A one-way transmission to initiate, modify, or terminate
functions of a device at a distance.
A one-way transmission of measurements at a distance from the measuring instrument.
transmission The method of sending an information signal.
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.
UHF (Ultra-high frequency) The frequency range 300-3000 MHz.
VHF (Very-high frequency) The frequency
range 30-300 MHz.
(watt) A unit of electrical power. One watt results when one ampere of current flows through an electrical potential difference
of one volt.
The length of a wave in meters is equal to its velocity (V) divided by its frequency (F) in Hz. The velocity
of an electromagnetic wave is equal to the speed of light (300,000,000 meters per second in free space). Wavelength = 300,000,000/F
wavelength band The approximate wavelength
in meters of an amateur service frequency band. 40 meters = 7.000-7.300 Hz.
150HA1A Emission designator indicating a CW international Morse code telegraphy
transmission. The necessary bandwidth is expressed by 150H i.e., 150 Hz. The first symbol A indicates
a double-sideband emission. The symbol 1 indicates a single channel containing quantized or digital information without
the use of a modulating sub-carrier, excluding time-division multiplex. The second symbol A indicates on-off telegraphy
for aural reception.
Emission designator indicating a narrow data transmission. The necessary bandwidth is expressed by 2K80,
i.e., 2.80 kHz. The letter K occupies the position of the decimal point. The symbol J indicates a single
sideband suppressed carrier emission in which the main carrier is amplitude-modulated. The symbol 2 indicates a single
channel containing quantized or digital information with the use of a modulating sub-carrier, excluding time-division multiplex.
The symbol D indicates data transmission, telemetry, telecommand.
2K80J3 Emission designator indicating a narrow SSB-only phone transmission.
The necessary bandwidth is expressed by 2K80, i.e., 2.80 kHz. The letter K occupies the position of the
decimal point. The symbol J indicates a single sideband suppressed carrier emission in which the main carrier is
amplitude-modulated. The symbol 3 indicates a single channel containing analogue information. The symbol E
Emission designator indicating a narrow-band direct-printing telegraphy transmission, i.e., RTTY. The necessary
bandwidth is expressed by 60H0, i.e., 60 Hz. The symbol J indicates a single sideband suppressed
carrier emission in which the main carrier is amplitude-modulated. The symbol 2 indicates a single channel containing
analogue information. The symbol B indicates telegraphy for automatic reception,
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June 14, 2012
Supersedes all prior editions