4
Instructions for use
Background noise measurement (Noise)
NOTE: Do not use the monitor headphones on higher than volume 4 for this test, (i�e� on LO
range setting) in order to maintain accuracy and stability in the instrument�
1� Switch off or disconnect from the mains power any audio induction loop equipment,
(note that any other mains operated equipment, that normally would be in use within
the test area, should be switched on)�
2� Set the TONE (filter) switch to the NORM position (8)�
3� Move the RANGE switch to the LO position (9)�
4� Hold the meter in vertical position, with the top at the position a hearing aid is likely to
be used, (1�2m for sitting and/or 1�7m for standing height� If both sitting and standing
positions are used, measure at 1�45m)�
5� Observe the LED bar graph and document the background noise levels within the
listening area�
NOTE: For long time listening the IEC 60118-4 recommended background noise level
should be below -47dB� If the background noise level exceeds -32dB, the nature of the
magnetic noise should be assessed and remedial measures to achieve lower background
noise level should be considered� For short time announcements, background noise levels
of up to -22dB can be accepted, as the loop system will still be beneficial to hearing aid
user�
Field strength deviation/overspill (Coverage)
NOTE: For Field strength deviation/overspill (Coverage) measurement a precise 1kHz
frequency signal, Univox 1kHzSineWave�mp3 should be used�
1� Connect the loop driver to the mains power�
2� Connect the signal source and activate the audio file 1kHzSineWave�mp3�
3� Adjust the input level at the loop driver according to the manual�
4� Adjust the field strength level at a reference measuring position to approximately
-12dB�
5� Set the TONE (filter) switch to the NORM position (8)�
