No year listed but its old. The pictures in it seem to be like 1960's, not positive.
what is says on the cover is" Restricted" as the very top
Then "Manual for the Field Radio Operator" as the title
Signal school detachment replacement and training command MTOUSA APO 49
Then "Restricted" again at the bottom.
There is a mention "Army use" in the contents. Also in the history portion it mentions this manual has been used by several thousand students, including US Army, Navy and WAC, British and French Army personnel.
the signal corp training was at Ft Gordon Ga back in the late 60's early 70's that I know of ,we were stationed there for a while with my dad teaching there the APO is Army Post Office ,not sure which was 49 but hope this helps track it down some morefor you.