This is a field puzzle. The headline co ords take you to part 1. Then follow the sound to gz.
Liz and I tried it out and it appeared to be tempremental as sometimes it worked and sometimes it didn't. The unit and batteries are new so all should be working fine. Please persevere and if it doesn't work please use plaque on bench for a simple short set multi.
You will need to answer these questions:
How many letters in John's surname =A
Year = BCDE
The cache is located at N 50° 48. A C B
W 004° 18. (B+E) (D+E) (A+B)
Checksum of ABCDE =9