1JT65CODE(1) WSJT-X Manual JT65CODE(1)
2
6 jt65code, jt9code, jt4code - Weak signal communications encoding
7 support utility.
8
10 jt65code "MESSAGE"
11 jt65code [OPTIONS]
13 jt9code "MESSAGE"
15 jt9code [OPTIONS]
17 jt4code "MESSAGE"
19 jt4code [OPTIONS]
21
23 -t
24 Prints a selection of messages alongside their corresponding
25 decoded form and types.
26
28 jt65code, jt9code and jt4code are utility programs that let you explore
29 the conversion of user-level messages into channel symbols or “tone
30 numbers.” These programs can be useful to someone designing a beacon
31 generator for JT9 or JT65, or for studying behavior of the
32 error-control codes for each of the protocols.
33 Channel-symbol values for JT9 run from 0 to 8, with 0 representing the
35 sync tone. The total number of symbols in a transmitted message is 85.
36 To run jt9code, enter the program name followed by a JT9 message
37 enclosed in quotes. In Windows the command and program output might
38 look like this:
39 $ jt9code "G0XYZ K1ABC FN42"
41 Message: G0XYZ K1ABC FN42
42 Channel symbols:
43 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
44 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
45 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
46 Decoded message: G0XYZ K1ABC FN42
47 For the corresponding program jt65code only the information-carrying
49 channel symbols are shown, and the symbol values range from 0 to 63.
50 Sync synbols lie two tone intervals below data tone 0, and the
51 sequential locations of sync symbols are described in the JT65 Protocol
52 section of this Guide.
53 A typical execution of jt65code is shown below. The program displays
55 the packed message of 72 bits, shown here as 12 six-bit symbol values,
56 followed by the channel symbols:
57 $ jt65code "G0XYZ K1ABC FN42"
59 Message: G0XYZ K1ABC FN42
60 Packed message, 6-bit symbols: 61 36 45 30 3 55 3 2 14 5 33 40
61 Information-carrying channel symbols:
62 56 40 8 40 51 47 50 34 44 53 22 53 28 31 13 60 46 2 14 58 43
63 41 58 35 8 35 3 24 1 21 41 43 0 25 54 9 41 54 7 25 21 9
64 62 59 7 43 31 21 57 13 59 41 17 49 19 54 21 39 33 42 18 2 60
65 Decoded message: G0XYZ K1ABC FN42
66 For an illustration of the power of the strong error-control coding in
68 JT9, JT65 and JT4, try looking at the channel symbols after changing a
69 single character in the message. For example, change the grid locater
70 from FN42 to FN43 in the JT65 message:
71 $ jt65code "G0XYZ K1ABC FN43"
73 Message: G0XYZ K1ABC FN43
74 Packed message, 6-bit symbols: 61 36 45 30 3 55 3 2 14 5 33 41
75 Information-carrying channel symbols:
76 25 35 47 8 13 9 61 40 44 9 51 6 8 40 38 34 8 2 21 23 30
77 51 32 56 39 35 3 50 48 30 8 5 40 18 54 9 24 30 26 61 23 11
78 3 59 7 7 39 1 25 24 4 50 17 49 52 19 34 7 4 34 61 2 61
79 Decoded message: G0XYZ K1ABC FN43
80 You will discover that every possible JT65 message differs from every
82 other possible JT65 message in at least 52 of the 63
83 information-carrying channel symbols.
84 WSJT-X home page
86 http://www.physics.princeton.edu/pulsar/K1JT/wsjtx.html
87 WSJT-X User’s Guide
89 http://www.physics.princeton.edu/pulsar/K1JT/wsjtx-doc/wsjtx-main-2.1.2.html
90
92 Joe Taylor, K1JT.
93
95 jt65code, jt9code and jt4code are Copyright © 2001 - 2015 by Joseph H.
96 Taylor, Jr., K1JT, with contributions from additional authors. WSJT-X
97 is Open Source software, licensed under the GNU General Public License
98 (GPLv3).
99 These programs are distributed in the hope that they will be useful,
101 but WITHOUT ANY WARRANTY; without even the implied warranty of
102 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
103 General Public License for more details.
104AsciiDoc 2.1.2 03/31/2020 JT65CODE(1)