Attaching A Microphone And Adjusting Gain; Operating Notes; Adjusting The Transmitter Frequency - Lectrosonics UM400 Operating Instructions Manual

The –20 and –10 LEDs will blink:
• Once for 100 Series mode
• Two times for 200 Series mode
• Three times for some other receivers
• Four times for 400 Series mode
• Five times for IFB mode*
At powerup the transmitter will confirm the current compatibility mode with the number of blinks listed
here. This setting will remain the same until you reset it with the procedure listed above.

ATTACHING A MICROPHONE AND ADJUSTING GAIN

1) Ensure the battery is in good condition.
2) Insert the microphone plug into the input jack, aligning the pins; be sure that the connector locks.
3) Attach the antenna to the SMA connector on the top of the transmitter.
4) Mute the associated receiver's audio output.
5) Turn on the transmitter.
6) Position the microphone in the location you will use in actual
operation. While speaking or singing at the same voice level
that will actually be used, observe the Modulation LEDs. Adjust
the AUDIO LEVEL control until the –20 dB LED glows green
with occasional red flickers and -10 dB glows green. This will
set the gain of your transmitter to between +0 dB and +10 dB
modulation. (See chart to right.)
7) Once the gain has been adjusted, the audio system audio can
be turned on to make level adjustments in the main audio
system.
The transmitter Audio Level Control should not be used to control the volume of your sound system or recorder levels. This gain
adjustment matches the transmitter gain with the user's voice level and microphone positioning.
If the audio level is too high — both LEDs will blink red frequently or glow a steady red. This condition may reduce
the dynamic range of the audio signal.
If the audio level is too low — neither LED will glow, or only the -20 LED will glow green. This condition may cause
hiss and noise in the audio.
Different voices will usually require different settings of the AUDIO LEVEL control, so check this adjustment as each
new person uses the system. If several different people will be using the transmitter and there is not time to make
the adjustment for each individual, adjust it for the loudest voice.

ADJUSTING THE TRANSMITTER FREQUENCY

If you are experiencing interference from another signal on your fre-
quency, you may want to change the operating frequency of your
system. The left switch changes the operating frequency by
1.6 MHz per step and the right switch changes it 100 kHz per
step. Start by changing the operating frequency in 100 kHz
increments to find a clear channel. If it is not possible to find a
clear channel using the 100 kHz switch, return it to its original
position and change the 1.6 MHz switch by one click then try
the 100 kHz switch again.
To gain access to these switches, slide the access door sideways
with a fingernail.
With the 400 Series receivers, a front panel LCD character display will
indicate the correct transmitter switch settings.
*Not available on earlier units.
Frequency-Agile UHF Belt-Pack Transmitter
Note

OPERATING NOTES

Rio Rancho, NM – USA
-20 LED -10 LED
Signal Level
Less than -20 dB Off
-20 dB to -10 dB Green
-10 dB to +0 dB Green
+0 dB to +10 dB Red
Greater than +10 dB Red
0 1
F
E 2
D 3
C
4
B 5
A 6
9
7
8
1.6M
Off
Off
Green
Green
Red
0 1
F
E 2
D 3
C
4
B 5
A 6
9
7
8
100K
9