To reduce local magnetic disturbances, place the magnetometer in a box well separated from the power supply and pen recorder (the motor of the recorder could produce some nasty feedback).
It is a good idea to use your pen recorder while making tests.
The analog output can be used with data acquisition systems or pen recorders
They are suited for mobile phones, digital cameras, FM radios, MP3, PDAs, an electronic dictionary and pen recorders
The two options for chart recording are thermal array printers and pen recorders.
Doctors much prefer pen recorders," says Gould's Porter.