- What is the character to tone mapping of ISCAT A and B modes ?The WSJT9 online documentation gives the tone frequency and baud settings, but I can't find the alphabet and char/symbol mapping - that doesn't seem to be listedI'd like to do a PIC / Synthesizer implementation for some microwave testsAndy G4JNT
- Hi Andy et al
An "single" ISCATmessage is encoded in this way C-style, modified for general purposes. For "multiple" purposes it is repeated.
char ISCATChars="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ .?@-";
char Msg[MaxMessageLength+3]="@"; // add @, " " and sz
unsigned char I,MsgLen;
ISCAT is using 11025 Hz sampling rate and ISCAT-A uses 512 samples and ~B 256.
Details in geniscat.f90 (classic ISCAT = ISCAT-B) and WSJT home page for ISCAT-A.
The shown implementation applies only to messages less than 18 characters, excluding the @.
The " " is not needed so the array is only +2. It is a leftover from initial tests I carried out. The ISCAT carriers the message length so no " " needed to separate two decoded messages.