4
Batteries and power-up
Remove battery cover the on back of the FSM. Unwrap and insert batteries
into the unit ensuring correct polarity is observed. Replace battery cover.
Set the power switch to the ON (I) position and check the green power LED next to
it is illuminated. Note: As the unit is switched on the front panel meter will briefly
illuminate before settling to a measurement.
Method of use
For most applications it is the vertical component of the magnetic field that is
received by the hearing aid, as a result the FSM is designed to be used while held
vertically as shown:
Mode selection
All modes measure Audio frequency magnetic fields using the internal pickup coil
Meter Mode
Reference
Filtering
Signal
Frequency
response
Compare levels
between bands
1/3 Octave bands of
100Hz, 1kHz & 5kHz
Pink
noise
Field
strength
0dB or 400mA/m
Flat 50Hz to 8kHz
Any
Background
noise
-20dB or
40mA/m
A-weighted
System
off
Frequency Selection
Switch between one of the three 1/3 octave band filters when in Frequency
response mode. While running pink noise, use the 1dB increment range of the
scale to see how the 100Hz, and 5kHz levels compare with 1kHz.
Headphones and volume adjustment
Insert the headphones into the socket on the top panel of the unit, and adjust the
volume using the adjacent thumbwheel.
Standing or seated depending
on system use.
Typically:
1.2m for seated persons
1.7m for standing adults
Beyond this there is a range of
use that must be considered -
see
Test commissioning
procedure
part 1 ‘
Volume of
use
’ for further details.
Standing
Seated