User Manual

6
UT400
LECTROSONICS, INC.
Power
LED
Pow er
Switch
Audio Level LEDs
-20 -10
Frequency Switches
Coarse Fine
Audio Level
CONTROLS AND FUNCTIONS
“P” SWITCH – POWER ON/OFF
A slide switch (located on the outside bottom of the unit)
which turns battery power on and off. The pilot tone
muting system prevents “thumps” or transients from
occurring even when the switch is turned off or on
abruptly,
The Power LED glows green when the battery is good and
the ON/OFF switch is ON. The lamp will glow red as the
battery voltage drops and finally flashes when there is
about 30 minutes of operation left with the recommended
alkaline battery. The lamp will flash red when there are
only a few minutes of life left. A NiMh battery will give
little or no warning when it is depleted. If you wish to use
NiMh batteries in the UM400, we recommend trying fully
charged batteries in the unit, noting the length of time that
the batteries will run the unit and in the future use some-
what less than that time to determine when the battery
needs to be replaced. A weak battery will sometimes light
the POWER LED to the “good” green indication immedi-
ately after being put in the unit, but will soon discharge to
the point where the LED will go red or shut down, just like
a flashlight with “dead” batteries. If the lamp fails to light,
the battery should be replaced.
FREQUENCY ADJUST
Two rotary switches (located under the battery door) adjust
the center frequency of the carrier. The Coarse adjust-
ment adjusts the frequency in 1.6 MHz steps and the fine
in 100 kHz steps. Each transmitter is factory aligned at
the center of its operating range for uniform operation
across the entire band. The default position of the fre-
quency select switches is in the center of the transmitter
range.
MOD LEVEL LEDs
These LEDs (located under the battery door) indicate the
proper setting of the MIC LEVEL control. There are two
bicolor modulation LEDs that can light either red or green.
“-20dB level” One modulation LED glows green and the transmitter is 20 dB below full modulation.
“-10 dB level” Both modulation LEDs glow green and the transmitter is close to full modulation.
“+0 dB level” The -20 LED glows red and the -10 LED glows green. The transmitter is in slight limiting and is fully
modulated. This is probably desirable. See the discussion below under Input Limiter.
“+10 dB level” Both LEDs are red. The transmitter is in limiting and you may want to reduce the transmitter audio
gain. See the discussion below under Input Limiter.