Thank you Neils for the link, I saw it before. This morning I solve the issue! My starting point was
https://github.com/g4eev/RSPduoEME/blob/main/processthread.cpp
code page. Since my app is written in C# porting code was neccessary. After analysing Linrad
UDP output I was convince that everything is identical but spectrum was inverted. After even more
analysis I found in MAP65 source code file soundin.cpp file and in function a2dCallback code comment
/Negate odd-numbered frames (not sure why is this done). Now UDP transfer is working in 1ch or 2ch
mode from my app but with Linrad  spectrum is still inverted (not sure about RSPdue).
Now I'm waiting second part of ARRL EME contest to test hardware and software setup.

73 de yt7pwr