Redback Q 2012 User manual
www.redbackaudio.com.au Redback® Proudly Made In Australia 1
Redback® Q 2012 Field Strength Meter
INTRODUCTION:
The Redback® Q 2012 Field strength Meter is absolutely essential for all installers setting up and commisioning hearing
induction loop amplier systems. It is ideally used in conjunction with the Redback® Q 2014 1kHz tone generator allowing
an installer to test the signal generated in the actual ‘loop’ of the system. The resultant signal is ‘induced’ into the pickup of
the Q 2012 tester and the strength of the signal is displayed on the LED display.
It is also ideal for measuring any electrical noise that may be present within the loop precinct, which should be done prior
to the loop installation.
The signal strength and quality can also be monitored via headphones, which can be plugged directly into the Q 2012.
The meter has an internal Li-Ion battery which is recharged via a 5V Dc source such as a USB connection.
OPERATION:
Use the “Power” switch to turn the Redback® Q 2012 ON or OFF.
The Q 2012 is also equipped with an auto power off function. The unit will automatically power down after a period of
about four minutes, saving precious battery life.
There are two modes of operation available, Field Strength and Background Noise, which are selected by the switch on the
end of the Q 2012.
Testing The Field Strength:
Use this mode to determine the db levels of the active loop.
The eld Strength is tested to Australian Standard AS60118.4 (2007), using a 1kHz sinusoidal input, with a variation of +/-
3dB. An extract of the standard is supplied on the next page.
In practical terms, the recommended eld strength should be 100mAmps/metre with a long term average >60 secs.
i.e. -12dB ref 400mA/m (rms). This is the “Field Strength Average” which is shown as the -12dB point on the LED scale on
the front of the Q 2012. This is the average reading which needs to be achieved in the listening area.
The recommended eld strength maximum should be 400mAmps/metre for 0.125secs. This becomes the 0dB reference.
The “Field Strength Maximum” is shown as the 0dB point on the LED scale on the front of the Q 2012. The Field Strength
in the listening area should not exceed this 0dB level.
When testing the Field Strength, we recommend connecting the Redback® Q 2014 Audio Generator which has a 1kHz si-
nusoidal output, to the input of the loop amplier (as shown in gure 1). The output level of the amplier is then adjusted
to achieve the “Field Strength Average” as measured by the Redback® Q 2012 Field Strength meter.
(Note: When measuring the Field Strength, the Q 2012 should be held vertical for best results).
Operating Manual
User manual revision number: 1.0 04/11/2020
www.redbackaudio.com.auRedback® Proudly Made In Australia2
Redback® Q 2012 Field Strength Meter
DRAFT
Fig 1
Testing The Background Noise:
Use this mode to determine the db levels of background noise, in and around the area the loop is to be installed. The loop
must be inactive when testing in this mode.
Measure the environmental background electromagnetic noise with the loop system off.
The required gure is -32dB (re 400mA/m), but ideally a preferred gure is -47dB! A level of -22dB is useable but must be
reported.
HEADPHONE SOCKET
The audio from the loop being tested, can be monitored by connecting a set of headphones to the 3.5mm socket on the
end of the Q 2012. The Volume knob will adjust the level to the headphones.
BATTERY CHARGING
The “LOW BATTERY” LED will illuminate when the battery requires recharging.
To recharge the internal battery, connect the supplied USB lead to a 5VDC USB source, and connect the other end to the
charging socket located on the end of the Q 2012. The blue “CHARGING” LED will illuminate when the unit is charging.
When the battery is charged, the unit will stop charging and the LED will turn off. The charger can then be unplugged. The
inbuilt charging circuit is a slow charger and may take up to 12 hours to charge a completely at battery.
REPLACEMENT PARTS
The Redback® Q 2012 Field Strength Meter is supplied with a charging lead. If replacements or spares are required they are
available from Altronics (www.altronics.com.au). The part number is P 6703 - USB Type A Male to 1.35mm DC Plug lead.
Extract from AS60118.4 (2007)
Audio Generator
Model : Q 2014
Outputs
ON/OFF Low
Level
High
Level
RISK OF ELECTRIC SHOCK
OPEN BY QUALIFIED
PERSONNEL ONLY !
CAUTION
+
–
240V AC @ 50Hz
Line Mic
OUTPUT
L
R
Aux
Ewis
L
R
Vox
Sens.
+24V DC FUSE -24V DC FUSE
Made in Australia by
Altronic Distributors Pty Ltd
www.altronics.com.au
DIP Switch Options
SW
1
2
On O
Vox enabled Vox disabled
Phantom Power O
3
Not Used
4
Phantom Power On
Not Used
DIP
Switches 2 1
3
ON
1 2 3 4
2 1
3
PHASE
SHIFT
(When Internal
module tted.)
LOOP RESISTANCE (0.2Ω TO 1.7Ω. MAX 2Ω)
Q 2014
A 4210 AMPLIFIER
Typical connection between
the Q 2014 Audio Generator
and the Redback A 4210 and
A 4212 Hearing Loop Ampliers.
Single RCA to Dual RCA lead
(such as Altronics P 6280A)
“Magnetic Field Strength in Audio-Frequency Induction Loops for Hearing Aid Purposes”: The rigorous standard for Au-
dio Induction Loop Systems, making Australia internationally compliant in regard to eld strength and audio quality for
the hearing impaired. This denes the performance criteria of an induction loop system. The key elements may be
summarised:
• Field Strength in the specied listening area shall be -20dB re 1A/m average i.e. 100mA/metre long term aver-
age, using a 1kHz sinusoidal input, with a variation of +/-3dB.
• short term peaks up to 400mAmps/metre (0.125secs integration time)
• Environmental Magnetic Background noise shall be no higher than -40dB A-weighted (measured with the loop
system off).
• Frequency Response of the system shall be from 100Hz to 5000Hz. The variation should be no more than +/-
3dB from the value taken at 1kHz.
The international standard is IEC 60118.4 (also known as SN, EN or BS 60118.4)
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