Lectrosonics UM500 - Manual (Page 7)

Belt Clip
Belt Clip Retaining Screw Location
Frequency-Agile UHF Belt-Pack Transmitter
MODULATION LEDS
The Modulation LEDs provide a visual indication of the input audio signal level from the microphone. These two
bicolor LEDs can glow either red or green to indicate modulation
levels.
The Modulation LEDs are also used to indicate the Compatibility
Mode when the transmitter is initially turned on. The Modulation
LEDs will blink simultaneously:
• Once for 110 Series mode
• Two times for 300 Series mode
• Three times for mode 3
• Four times for Digital Hybrid Wireless
™ or 500 Series mode
Signal Level -20 LED -10 LED
Less than -20 dB Off Off
-20 dB to -10 dB Green Off
-10 dB to +0 dB Green Green
+0 dB to +10 dB Red Green
Greater than +10 dB Red Red
• Five times for IFB mode*
ANTENNA
The flexible galvanized steel cable antenna supplied with the transmitter is cut to 1/4 wavelength of the center of the
frequency block (the frequency range) of the transmitter. It is removable via an SMA connector. The SMA connector
is a 50 Ohm RF port which can also be connected directly to test equipment. Replacement antennas are available in
pre-cut lengths for specific frequency blocks, or as a kit with instructions to cut the antenna for any frequency block.
FREQUENCY SELECT SWITCHES
Two 16-position rotary switches adjust the center frequency of the carrier. The 1.6M is a coarse adjustment and the
100K is the fine adjustment.
ADJUSTABLE LOW FREQUENCY ROLL-OFF
A 18dB per octave low frequency roll-off is provided in the audio section, with the -3dB point adjustable from 35Hz to
150Hz. The actual roll-off frequency will vary somewhat according to the low frequency response of the mic capsule
being used.
The low frequency roll-off control is used to remove subsonic (or very low frequency) audio, often produced by air
conditioning systems, automobile traffic and other sources from the audio signal. Excessive low frequency content
in the audio input can cause a variety of audio problems including driving the transmitter into limiting. In sound
reinforcement systems, as one instance, excessive low frequency content can cause excessive power amplifier drain
or even damage to loudspeaker systems. By rotating the control clockwise, the hinge point of the roll-off is increased
to reduce the level of low frequencies. In controlled situations, such as a motion picture production set indoors
where environmental noise is minimal, the control can be rotated counter-clockwise to permit low frequency audio to
be captured.
BELT CLIP
The belt clip may be removed for special applications by removing one screw.
WARNING
USE ONLY THE SCREW THAT IS SUPPLIED
The circuitry is tightly packed into this unit. A longer screw will permanently damage the
transmitter! Use only Lectrosonics PN:28528 which is a Phillips head, 4-40 x 3/16",
FL100 screw.
*Not available on earlier units.
Rio Rancho, NM – USA
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