9
13. Set the field strength
(6)
to -3dB to 0dB at the peaks. If
Peak
(8)
LED flickers only
momentarily the connection is acceptable. If the
Peak
LED indicates continuously, try
rewiring the connections in the junction box in subsequent order:
II)
one wire single
turn and then
III)
two parallel wires single turn.
With this procedure the unit will operate at the highest output possible without
generating any excessive heat.
Note
: To quickly set up the field strength for a real program source, a PPM instrument
is helpful. The Univox Listener has a calibrated level indicator that quickly finds the
highest peak.
Note
: When adjusting the field strength peaks, -2dB field strength works best, due to
different dynamic headrooms in hearing aids.
14. Check basic frequency response according to IEC 60118-4, using a field strength meter,
e.g Univox FSM. If necessary, follow
Frequency adjustment procedure
(see page 10).
15. Check the sound quality by using an external listening device (Univox Listener or FSM),
Monitor speaker connector
(14)
or
Monitor
(9)
for headphone (volume control on rear
panel
Monitor
(13)
). When operating at maximum output on low impedance, i.e single
turn loops, the automatic limit protection circuit may cut programme peaks. This can
be avoided by changing to a 2-turn loop or reduce the output current setting.
16. Start the Commissioning
process to certify the installation (see page 7).
LOOP
Amplifier
Junction
Box
1
1
2
2
Loop
wire
I) 2-turn serial
connection
Junction
Box
1
1
2
2
Loop
wire
III) two parallel wires
single turn
Amplifier
Junction
Box
1
1
2
2
Loop
wire
II) one wire single turn
NC
NC
JUNCTION
JUNCTION
JUNCTION
LOOP
Amplifier
LOOP