All:
I just used Version 1.8.8 of the Arduino IDE and it appears that the code does NOT work with that version. As you can see here:
it does work on 1.8.7. So, even though the latest doc file shows the 1.8.8 compiler, don't upgrade for now until I figure out where the issue is with 1.8.8. (This is one reason why my system has 18 versions of the IDE on it going back to 1.05.)
Also, look in the JackAl.h header file at the #include files. Any non-standard libraries will have the download URL as a comment on the line where you can download/install the new libraries. Some of these libraries have changed in recent months, so you might want to update them. Don't forget, you must close the IDE after any new library is installed and reopen it for the new library to be accessed. Also, the standard RA8875 library is missing a modification we did to it. You? can download our version from the hamradiodesigns.com web site.
Jack, W8TEE
jjpurdum