115 lines
3.7 KiB
Plaintext
115 lines
3.7 KiB
Plaintext
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:doctype: manpage
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:man source: AsciiDoc
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:man version: {VERSION}
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:man manual: WSJT-X Manual
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= jt65code(1)
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== NAME
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jt65code, jt9code, jt4code - Weak signal communications encoding support utility.
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== SYNOPSIS
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*jt65code* "'MESSAGE'"
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*jt65code* ['OPTIONS']
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*jt9code* "'MESSAGE'"
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*jt9code* ['OPTIONS']
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*jt4code* "'MESSAGE'"
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*jt4code* ['OPTIONS']
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== OPTIONS
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*-t*::
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Prints a selection of messages alongside their corresponding
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decoded form and types.
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== DESCRIPTION
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*jt65code*, *jt9code* and *jt4code* are utility programs that let you
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explore the conversion of user-level messages into channel symbols or
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“tone numbers.” These programs can be useful to someone designing a
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beacon generator for JT9 or JT65, or for studying behavior of the
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error-control codes for each of the protocols.
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Channel-symbol values for JT9 run from 0 to 8, with 0 representing the
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sync tone. The total number of symbols in a transmitted message is
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85. To run jt9code, enter the program name followed by a JT9 message
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enclosed in quotes. In Windows the command and program output might
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look like this:
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.....
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$ jt9code "G0XYZ K1ABC FN42"
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Message: G0XYZ K1ABC FN42
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Channel symbols:
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0 0 7 3 0 3 2 5 4 0 1 7 7 7 8 0 4 8 8 2 2 1 0 1 1 3 5 4 5 6
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8 7 0 6 0 1 8 3 3 7 8 1 1 2 4 5 8 1 5 2 0 0 8 6 0 5 8 5 1 0
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5 8 7 7 2 0 4 6 6 6 7 6 0 1 8 8 5 7 2 5 1 5 0 4 0
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Decoded message: G0XYZ K1ABC FN42
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.....
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For the corresponding program jt65code only the information-carrying
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channel symbols are shown, and the symbol values range from 0 to
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63. Sync synbols lie two tone intervals below data tone 0, and the
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sequential locations of sync symbols are described in the JT65
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Protocol section of this Guide.
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A typical execution of jt65code is shown below. The program displays
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the packed message of 72 bits, shown here as 12 six-bit symbol values,
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followed by the channel symbols:
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.....
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$ jt65code "G0XYZ K1ABC FN42"
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Message: G0XYZ K1ABC FN42
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Packed message, 6-bit symbols: 61 36 45 30 3 55 3 2 14 5 33 40
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Information-carrying channel symbols:
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56 40 8 40 51 47 50 34 44 53 22 53 28 31 13 60 46 2 14 58 43
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41 58 35 8 35 3 24 1 21 41 43 0 25 54 9 41 54 7 25 21 9
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62 59 7 43 31 21 57 13 59 41 17 49 19 54 21 39 33 42 18 2 60
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Decoded message: G0XYZ K1ABC FN42
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.....
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For an illustration of the power of the strong error-control coding in
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JT9, JT65 and JT4, try looking at the channel symbols after changing a
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single character in the message. For example, change the grid locater
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from FN42 to FN43 in the JT65 message:
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.....
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$ jt65code "G0XYZ K1ABC FN43"
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Message: G0XYZ K1ABC FN43
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Packed message, 6-bit symbols: 61 36 45 30 3 55 3 2 14 5 33 41
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Information-carrying channel symbols:
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25 35 47 8 13 9 61 40 44 9 51 6 8 40 38 34 8 2 21 23 30
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51 32 56 39 35 3 50 48 30 8 5 40 18 54 9 24 30 26 61 23 11
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3 59 7 7 39 1 25 24 4 50 17 49 52 19 34 7 4 34 61 2 61
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Decoded message: G0XYZ K1ABC FN43
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.....
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You will discover that every possible JT65 message differs from every
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other possible JT65 message in at least 52 of the 63
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information-carrying channel symbols.
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WSJT-X home page:: http://www.physics.princeton.edu/pulsar/K1JT/wsjtx.html
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WSJT-X User's Guide::
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http://www.physics.princeton.edu/pulsar/K1JT/wsjtx-doc/wsjtx-main-{VERSION}.html
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== AUTHOR
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Joe Taylor, K1JT.
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== COPYING
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*jt65code*, *jt9code* and *jt4code* are Copyright (C) 2001 - 2015 by
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Joseph H. Taylor, Jr., K1JT, with contributions from additional
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authors. WSJT-X is Open Source software, licensed under the GNU
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General Public License (GPLv3).
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These programs are distributed in the hope that they will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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