mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-04 16:31:17 -05:00
60 lines
2.7 KiB
Plaintext
60 lines
2.7 KiB
Plaintext
|
// Status=review
|
||
|
|
|
||
|
|
Utility programs *+jt9code+* and *+jt65code+* let you explore the
|
||
|
|
conversion of user-level messages into channel symbols or ``tone
|
||
|
|
numbers,'' and back again. These programs can be useful to someone
|
||
|
|
designing a beacon generator for JT9 or JT65, for understanding the
|
||
|
|
permissible structure of transmitted messages, and for studying
|
||
|
|
behavior of the error-control codes.
|
||
|
|
|
||
|
|
Channel-symbol values for JT9 run from 0 to 8, with 0 representing the
|
||
|
|
sync tone. The total number of symbols in a transmitted message is
|
||
|
|
85. To run +jt9code+, enter the program name followed by a JT9
|
||
|
|
message enclosed in quotes. In Windows the command and program output
|
||
|
|
might look like this:
|
||
|
|
|
||
|
|
C:\WSJTX> jt9code "G0XYZ K1ABC FN42"
|
||
|
|
Message: G0XYZ K1ABC FN42
|
||
|
|
Channel symbols:
|
||
|
|
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
|
||
|
|
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
|
||
|
|
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
|
||
|
|
Decoded message: G0XYZ K1ABC FN42
|
||
|
|
|
||
|
|
For the corresponding program *+jt65code+* only the
|
||
|
|
information-carrying channel symbols are shown, and the symbol values
|
||
|
|
range from 0 to 63. Sync synbols lie two tone intervals below data
|
||
|
|
tone 0, and the sequential locations of sync symbols are described in
|
||
|
|
the <<JT65PRO,JT65 Protocol>> section of this Guide.
|
||
|
|
|
||
|
|
A typical execution of +jt65code+ is shown below. The program
|
||
|
|
displays the packed message of 72 bits, shown here as 12 six-bit
|
||
|
|
symbol values, followed by the channel symbols:
|
||
|
|
|
||
|
|
C:\WSJTX> jt65code "G0XYZ K1ABC FN42"
|
||
|
|
Message: G0XYZ K1ABC FN42
|
||
|
|
Packed message, 6-bit symbols: 61 36 45 30 3 55 3 2 14 5 33 40
|
||
|
|
Information-carrying channel symbols:
|
||
|
|
56 40 8 40 51 47 50 34 44 53 22 53 28 31 13 60 46 2 14 58 43
|
||
|
|
41 58 35 8 35 3 24 1 21 41 43 0 25 54 9 41 54 7 25 21 9
|
||
|
|
62 59 7 43 31 21 57 13 59 41 17 49 19 54 21 39 33 42 18 2 60
|
||
|
|
Decoded message: G0XYZ K1ABC FN42
|
||
|
|
|
||
|
|
For an illustration of the power of the strong error-control coding in
|
||
|
|
JT9 and JT65, try looking at the channel symbols after changing a
|
||
|
|
single character in the message. For example, change the grid locator
|
||
|
|
from +FN42+ to +FN43+ in the JT65 message:
|
||
|
|
|
||
|
|
C:\Users\joe\wsjt\wsjtx_install>jt65code "G0XYZ K1ABC FN43"
|
||
|
|
Message: G0XYZ K1ABC FN43
|
||
|
|
Packed message, 6-bit symbols: 61 36 45 30 3 55 3 2 14 5 33 41
|
||
|
|
Information-carrying channel symbols:
|
||
|
|
25 35 47 8 13 9 61 40 44 9 51 6 8 40 38 34 8 2 21 23 30
|
||
|
|
51 32 56 39 35 3 50 48 30 8 5 40 18 54 9 24 30 26 61 23 11
|
||
|
|
3 59 7 7 39 1 25 24 4 50 17 49 52 19 34 7 4 34 61 2 61
|
||
|
|
Decoded message: G0XYZ K1ABC FN43
|
||
|
|
|
||
|
|
You will discover that every possible JT65 message differs from every
|
||
|
|
other possible JT65 message in at least 52 of the 63
|
||
|
|
information-carrying channel symbols.
|