If you have ever obtained a license from the FCC or spent anytime looking at your radios manual you will notice a seven digit code. Like 11K2F3E or 20K0F3E. Its not there for decoration, it actually means something. The first four digits, in the example above, stand for occupied bandwidth in kilohertz. So 20K0 would signify 20 Kilohertz of bandwidth. 11K2 would signify 11.2 kilohertz. The last three digits signify the type of emission. F3E stands for analog voice. Below is a handy guide we put together to help you figure out what these mean:
The letter goes where the decimal point should be placed, and denotes a magnitude:
H Hz
K kHz
M MHz
G GHz
Some common bandwidths are:
400 Hz 400H
2.4 kHz 2K40
11.2 kHz 11K1
6 MHz 6M00
M = Modulation Type
N None
A AM (Amplitude Modulation), double sideband, full carrier
H AM, single sideband, full carrier
R AM, single sideband, reduced or controlled carrier
J AM, single sideband, suppressed carrier
B AM, independent sidebands
C AM, vestigial sideband (commonly analog TV)
F Angle-modulated, straight FM
G Angle-modulated, phase modulation (common; sounds like FM)
D Carrier is amplitude and angle modulated
P Pulse, no modulation
K Pulse, amplitude modulation (PAM, PSM)
L Pulse, width modulation (PWM)
M Pulse, phase or position modulation (PPM)
Q Pulse, carrier also angle-modulated during pulse
W Pulse, two or more modes used
X All cases not covered above
N = Nature of modulating signal
0 None
1 Digital, on-off or quantized, no modulation
2 Digital, with modulation
3 Single analog channel
7 Two or more digital channels
8 Two or more analog channels
9 Composite, one or more digital channel, one or more analog
X All cases not covered above
I = Information type
N None
A Aural telegraphy, for people (Morse code)
B Telegraphy for machine copy (RTTY, fast Morse)
C Analog fax
D Data, telemetry, telecommand
E Telephony, voice, sound broadcasting
F Video, television
W Combinations of the above
X All cases not covered above
Packet Data/Teleprinters
with Audio Sub-Carrier 20F2 20K0F2B
Data with Audio Sub-carrier 3F2 3K00F2D
6F2 6K00F2D
20F2 20K0F2D
Analog Voice 20F3 20K0F3E
Digital Voice 20F3Y 20K0F1E
Digital Facsimile without
Audio Sub-Carrier 20F4 20K0F1C
Digital Facsimile with
Audio Sub-Carrier 20F4 20K0F2C
Analog Facsimile 20F4 20K0F3C
Composite of Digital &
Analog Information 3F9 3K00F9W
6F9 6K00F9W
20F9 20K0F9W
Packet Data/Teleprinters
without Audio Sub-Carrier 20F9Y 20K0F1B
Digital Data 20F9Y 20K0F1D
LAND MOBILE EMISSIONS MICROWAVE EMISSIONS
old new old new old new
A0 N0N P0 P0N F9 F8W (If bw is less than
A1 A1A P9 P0N 50 convert to F2D)
A3 A3E A2J J2B F9Y F7W (If bw is less than
A3J J3E A3H H3E 50 convert to F2D)
A7J J8W A9J J9W F3 F3E
A9 A9W P1 P1D A9Y A7W
A9Y A1D F2Y F2D A5 A3F
F0 N0N A0H H0N A9 A8W
F1 F1B A7 A8D A5C C3F
F2 F2D F7 F8D F2 F2D
F3 F3E F5 F3F
F3Y F1E
F4 F3C
F9 F9W
F9Y F1D
A2H H2D
A2 A2D
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And here is the relevant section of FCC rules:
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From General Docket No. 80-739
Section 2.201 Emission, modulation, and transmission characteristics.
The following system of designating emission, modulation, and
transmission characteristics shall be employed.
(a) Emissions are designated according to their classification and
their necessary bandwidth.
(b) A minimum of three symbols are used to describe the basic
characteristics of radio waves. Emissions are classified and
symbolized according to the following characteristics:
(1) First symbol - type of modulation of the main carrier;
(2) Second Symbol - nature of signal(s) modulating the main
carrier;
(3) Third symbol - type of information to be transmitted.
NOTE: A fourth and fifth symbol are provided for additional
information and are shown in Appendix 6, Part A of the ITU Radio
Regulations. Use of the fourth and fifth symbol is optional.
Therefore, the symbols may be used as described in Appendix 6,
but are not required by the Commission.
(c) First Symbol - types of modulation of the main carrier:
(1) Emission of an unmodulated carrier N
(2) Emission in which the main carrier is amplitude-
modulated (including cases where sub-carriers are angle
modulated):
- Double-sideband A
- Single-sideband, full carrier H
- Single-sideband, reduced or variable level carrier R
- Single-sideband, suppressed carrier J
- Independent sidebands B
- Vestigial sideband C
(3) Emission in which the main carrier is angle-modulated:
- Frequency modulation F
- Phase modulation G
NOTE: Whenever frequency modulation "F" is indicated,
Phase modulation "G" is also acceptable.
(4) Emission in which the main carrier is amplitude and
angle-modulated either simultaneously or in a pre-
established sequence D
(5) Emission of pulses:*
- Sequence of unmodulated pulses P
- A sequence of pulses:
- Modulated in amplitude K
- Modulated in width/duration L
- Modulated in position/phase M
- In which the carrier is angle-modulated during the
period of the pulse Q
- Which is a combination of the foregoing or is
produced by other means V
(6) Cases not covered above, in which an emission consists
of the main carrier modulated, either simultaneously or
in a pre-established sequence, a combination of two or
more of the following modes: amplitude, angle, pulse W
(7) Cases not otherwise covered X
*Emissions where the main carrier is directly modulated by a
signal which has been coded into quantized form (e.g.,
pulse code modulation) should be designated under (2) or
(3).
(d) Second Symbol- nature of signal(s) modulating the main
carrier:
(1) No modulating signal 0
(2) A single channel containing quantized or digital
information without the use of a modulating sub-
carrier, excluding time-division multiplex 1
(3) A single channel containing quantized or digital
information with the use of a modulating sub-carrier,
excluding time-division multiplex 2
(4) A single channel containing analogue information 3
(5) Two or more channels containing quantized or digital
information 7
(6) Two or more channels containing analogue information 8
(7) Composite system with one or more channels containing
quantized or digital information, together with one or
more channels containing analogue information 9
(8) Cases not otherwise covered X
(e) Third Symbol - type of information to be transmitted:
(1) No information transmitted N
(2) Telegraphy - for aural reception A
(3) Telegraphy - for automatic reception B
(4) Facsimile C
(5) Data transmission, telemetry, telecommand D
(6) Telephony (including sound broadcasting) E
(7) Television (video) F
(8) Combination of the above W
(9) Cases not otherwise covered X
(f) Type B emission: As an exception to the above principles,
damped waves are symbolized in the Commission's rules and
regulations as type B emission. The use of type B emissions
is forbidden.
(g) Whenever the full designation of an emission is necessary,
the symbol for that emission, as given above, shall be
preceded by the necessary bandwidth of the emission as
indicated in Section 2.202 (b) (1).
Section 2.202 Bandwidths.
(b) Necessary bandwidths.
(1) The necessary bandwidth shall be expressed by three
numerals and one letter. The letter occupies the
position of the decimal point and represents the unit
of bandwidth. The first character shall be neither
zero nor K, M or G.
Source: landmobile.com
Informative article.
ReplyDeleteThanks !