On 14/05/2019 22:26, Derek Turner via wsjt-devel wrote:
So I know I am looking in the right place, which is the eight bytes
starting at (zero base) byte 32 . Here is a screen shot from an Excel
worksheet where I compare samples of the Band Activity DT with their
Decode byte array bytes:-
Inline image
I have several issues here that I do not understand :-
1. The pattern of bytes for negative and positive Delta Times are
identical so the sign is lost.
2. Between SNR and Delta Frequency there are nine bytes, not the eight
I expected for a Double. Byte 40 appears to be surplus.
3. DT 0 is suspiciously all zeros when DT 0.1 seems to be a very large
number.
4. Bytes 33 and 34 are identical.
Please can somebody make sense of this for me.
Hi Derek,
beware of assuming fixed start positions for fields in the messages, if
there are preceding string fields then the following fields will be
moved according the length of the string field(s). You will be ok in
this case so long as you always start WSJT-X with the same command line
parameters.
The main issue is that you are not allowing for the fields in the
message being stored in network byte order, i.e. Big Endian. If you are
receiving on a little Endian architecture then you must swap the bytes
of any numeric fields longer than one byte.
73
Bill
G4WJS.
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