“If the needle jumps at 14.2 MHz, do not recalibrate,” one note read. “That is not interference. That is the heartbeat.”

Gemel E-526 Review based on user manual analysis (simulated)

The final entry in the manual was handwritten, in faded red ink:

For a complete PDF of the installation and user guide, you can check these enthusiast and manual archives:

Keep the unit away from high-frequency electromagnetic fields (like large unshielded motors).