Lectrosonics UDR700 Operating Instructions Manual page 11

ANTENNAS AND RF SIGNALS
Diversity indicator has three leds on and never moves.
The diversity mode switch is in the A or B position (using only one antenna) instead of the normal, center position
(using both antennas).
RF LEVEL is weak
• Antenna is disconnected or there is a bad connection
• Antenna may need to be moved or reoriented
• Improper length of antenna, or wrong antenna. UHF whip antennas should be about 3 to 5 inches long.
• Transmitter is 100kHz (one switch position) off from the receiver frequency.
AUDIO SIGNAL QUALITY
Microphone has a "whine" noise in the background which varies as the mic cable is moved.
The 700 Series modulation has an AM component which is more easily detected than FM by sensitive audio circuits.
A microphone that works fine on an FM system might not work on a 700 series system. To protect the microphone
from RF it is necessary to bypass it effectively at both ends of the cable. Ensure that bypass capacitors are installed
inside the connector housing. If the mic is not sufficiently bypassed at the capsule, it may be necessary to use a
different type of microphone. The UM700 transmitter is shipped with an M150 microphone which should work.
NOTE: the microphone plug wiring is different for the UM700 transmitter than for other Lectrosonics models (see the
transmitter manual for details). The M150 microphone supplied with the UM700 transmitter will not work with Lec-
trosonics 185/187 Series VHF belt-pack transmitters.
Poor signal to noise ratio
• Transmitter gain set too low
• Noise may not be in wireless system. Mute the audio signal at the transmitter and see if noise remains. If the noise
remains, then turn the power off at the transmitter and see if it remains. If the noise is still present, then the problem is
not in the transmitter.
• If noise is still present when the transmitter is turned off, try lowering the audio output level on the receiver rear panel
and see if the noise lowers correspondingly. If the noise remains, the problem is not in the receiver.
• Receiver output does not match the input of the device it is feeding. Try increasing the output level of the
receiver and lowering the input gain on the device the receiver is feeding.
Receiver outputs an extremely loud, hissy, swishy sound.
The encryption keys do not match. Follow the procedure under SETTING AND RESETTING THE ENCRYPTION KEY
to choose a new key and send it to the transmitter.
Distortion
• Transmitter input gain too high. Check and/or readjust input gain on transmitter according to the LEDs on the trans-
mitter and then verify the setting with the transmitter audio level LED strip on the receiver front panel.
• Audio output level too high for the device the receiver is feeding.
• Transmitter is 100kHz (one switch position) off from the receiver frequency.
No audio output, audio leds blinking in sequence, LED display
occasionally flashes "POWER TX OFF+ON" or "NEW KEY REQUIRED".
System is operating in security level 2 ("POWER TX OFF+ON") or 3 ("NEW KEY REQUIRED") and is not synchro-
nized. Either the receiver did not pick up the start of the transmission or the transmitter was out of reception range for
more than ten seconds. To correct this condition in security level 2, simply turn the transmitter off and on again. In
level 3, it will be necessary to generate a new key. (For detailed instructions on generating a new key, see SETTING
AND RESETTING THE ENCRYPTION KEY in the INSTALLATION AND OPERATING INSTRUCTIONS chapter.)
Security features vastly different from the documentation.
This manual applies only to UDR700 version V3.0/3.0 and higher. To check the version of the receiver, power it on and
note the version number displayed. To check the version of the transmitter, power it on and note whether the audio leds
blink to indicate security level 1, 2 or 3. Only version 3.0 and newer transmitters blink the security level at powerup. It
is usually possible to upgrade older systems. For details, please contact Lectrosonics.
Rio Rancho, NM – USA
Encrypted Digital Receiver
11