I looked today into this issue and detected, that UltraCompare always copies the content of the frame in UTF-8 format into the clipboard.
If you have UltraEdit you can open a new blank ASCII file, paste it and use File - Conversions - UTF-8 to ASCII (although it is an ASCII file) and save the now correct displayed characters as ASCII/ANSI file.
If you don't have UltraEdit, only Notepad, you have to open also a new blank ASCII file and paste the clipboard content from UltraCompare into the file, additionally insert at top of the file the 3 characters ï»¿. This is the BOM for UTF-8 files. Then save the file with Encoding ANSI, yes really. Close the file and open it again with Notepad. You will now see the ANSI characters correct. Save the file again and make sure that again the Encoding is set to ANSI. Notepad will convert now the file from UTF-8 to ANSI and you hopefully have what you want.