Lectrosonics UH200d User Manual
UH200D
FREQUENCY-AGILE
PLUG-ON UHF TRANSMITTER
OPERATING INSTRUCTIONS
and trouble-shooting guide
LECTROSONICS, INC.
Rio Rancho, NM
www.lectrosonics.com
INTRODUCTION
Thank you for selecting the Lectrosonics UH200D frequency agile, plug-on transmitter. The
UH200D combines over 80 years of engineering experience with the very latest components, in
a design that addresses the most demanding professional applications.
The design of the UH200D was the direct result of numerous conversations with users, staging
and touring companies and dealers across the US. The specific concerns and needs brought up
in these conversations led directly to the development of the operational features offered on the
UH200D. Two hundred fifty six frequencies are user selectable in 100kHz steps to alleviate
interference problems in travelling venues.
The UH200D is a rugged, machined aluminum package. Selectable voltage phantom power is
provided on pins 2 and 3. Level indicating LEDs are provided to make level settings quick and
accurate, without having to view the receiver. The battery compartment accepts any 9 Volt
alkaline or lithium battery and makes a positive connection via self-adjusting contacts.
Only the UH200D transmitter is covered in this manual. Companion receivers are covered in
separate manuals. The UH200D will operate with any 200 Series Lectrosonics receiver in the
same frequency group.
TABLE OF CONTENTS
INTRODUCTION ................................................................................................... 2
GENERAL TECHNICAL DESCRIPTION .............................................................. 3
CONTROLS AND FUNCTIONS ............................................................................ 4
OPERATING INSTRUCTIONS ............................................................................. 6
TROUBLESHOOTING .......................................................................................... 7
SPECIFICATIONS AND FEATURES.................................................................... 9
SERVICE AND REPAIR ...................................................................................... 10
RETURNING UNITS FOR REPAIR .................................................................... 10
WARRANTY .......................................................................................... Back cover
The UH200D transmitter is FCC type accepted under Part 74: 470 - 608MHz and 614 - 806MHz
2
Frequency Agile Plug-on UHF Transmitter
GENERAL TECHNICAL DESCRIPTION
The UH200D transmitters are comprised of a number of functional subsystems as shown in the block diagram below.
GENERAL
The 200 system uses 75kHz wide deviation for an extremely high
signal to noise ratio. The transmitter circuits are all regulated to
allow full output power from the beginning (9 Volts) to the end
(6.5 Volts) of battery life. The input amplifier uses an ultra low
noise op amp. It is gain controlled with a wide range input
compressor which cleanly limits input signal peaks over 30dB
above full modulation.
DUAL BAND COMPANDOR
Traditionally, compandors have been a source of distortion in
wireless microphone systems. The basic problem with conventional systems is that the attack and decay times are always a
compromise. If the time constants are fast, high frequency
transients will not be distorted, but this will cause low frequency
distortion. If the time constants are slower, low frequency audio
distortion will be low, but high frequency transients will then be
distorted. The 200 system introduces an entirely new approach
to solving this basic problem, called “dual-band companding.”
There are actually two separate compandors in the 200 system,
one for high frequencies and one for low frequencies. A crossover network separates the frequency bands at 1kHz with a 6dB
per octave slope, followed by separate high and low frequency
compandors. The attack and release times in the high frequency
compandor are fast enough to keep high frequency transient
distortion at a low level, and the low frequency compandor uses
slower time constants, reducing low frequency distortion to well
below that of a conventional compandor.
NO PRE-EMPHASIS/DE-EMPHASIS
The signal to noise ratio of the 200 system is high enough to
preclude the need for conventional pre-emphasis (HF boost) in
the transmitter and de-emphasis (HF roll off) in the receiver. Preemphasis and de-emphasis in an FM radio system usually
provides about a 10dB improvement in the signal to noise ratio of
the system, but the high frequency boost in the transmitter must
be removed in a purely complementary manner or else the
frequency response of the original audio signal will be altered.
Pre-emphasis can also cause distortion in the receiver. As this
signal is passed through the IF filters in the receiver, distortion
INPUT
JACK
SHUNT
LIMITER
+5V / +15V / +48V
BIAS SUPPLY
BUFFER
LIMIT
LED
SET
LED
INPUT
AMP
PEAK AUDIO
INDICATOR &
LIMITER
DRIVER
AUDIO
LEVEL
LP
FILTER
Vref
COMPANDOR
BASS
TREBLE
LP FILTER
HP FILTER
can be produced, most noticeable at full modulation. De-emphasis cannot be applied until the signal is converted into audio, so
there is no way around this problem short of eliminating preemphasis altogether. Neither of these problems occur in the 200
system. The dual-band compandor in the 200 Series system
essentially provides a dynamic pre-emphasis/de-emphasis function with extremely low distortion.
PILOT TONE SQUELCH
The 200 system utilizes an ultrasonic tone modulation of the
carrier to operate the receiver squelch. This “pilot tone” consists
of a 32kHz signal mixed with the audio signal after the compandor,
to control the audio output muting of the receiver. The pilot tone
is filtered out of the audio signal immediately after the detector in
the receiver so that it does not influence the compandor or
various gain stages. The basic benefit of the pilot tone squelch
system is that the receiver will remain muted until it receives the
pilot tone from the matching transmitter, even if a strong RF
signal is present on the carrier frequency of the system. This is
extremely important in applications that include an automatic
microphone mixer.
WIDE-BAND DEVIATION
±75kHz deviation improves the capture ratio, signal to noise ratio
and AM rejection of a wireless system dramatically, compared to
the more commonly used ±15kHz deviation.
LONG BATTERY LIFE
High efficiency circuits throughout the design allow over 4.5
hours of operation using a single 9 Volt alkaline battery. (A 9V
lithium battery will provide over 12 hours of operation.) The
battery compartment is a unique mechanical design which automatically adjusts to fit any brand of battery. The battery contacts
are spring loaded to prevent “rattle” as the unit is handled. The
battery life will be affected by the amount of phantom power
supplied to any microphones that require it. A high drain 48 Volt
microphone can shorten battery life by 40% or more. A light drain
15 Volt microphone will make little or no difference in battery life.
The only way to be sure is to test the transmitter and microphone
combination with a brand new battery; then and only then will you
be sure of the combination's battery life.
FREQUENCY AGILITY
The transmitter section uses a synthesized, frequency selectable
main oscillator. The frequency is extremely stable over a wide
temperature range and over time.
Two rotary switches, located
on the side panel of the unit,
provide 256 frequencies in
100kHz steps over a 25.5MHz
range. This alleviates carrier
interference problems in mobile or travelling applications.
PWR
LED
Vreg
Vreg
PILOT
TONE
OSC
+5VDC
+3.6VDC
COMPANDED AUDIO
TO XMTR
TO INPUT JACK
5V
48V
15V
BIAS
POWER
+9VDC
PHASE LOCKED LOOP
DIVIDER
FREQ
SWITCHES
PRESCALER
LOW PASS
FILTER
COMPANDED
AUDIO
VOLTAGE
CONTROLLED
OSCILLATOR
TRANSMITTER
Rio Rancho, NM – USA
50
ISOLATOR
UH200D Block Diagram
3
LIMIT LED
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
LEVEL LED
POWER
ON/OFF
LED
INPUT
JACK
MIC LEVEL
CONTROLS AND FUNCTIONS
INPUT
JACK
POWER
SWITCH
LEVEL
N O PHTM
P HTM
PWR OFF
5V
48 V
1 5V
PHANTOM POWER
VOLTAGE SELECT
FREQUENCY
1.6MHz 100kHz
FREQUENCY SWITCHES
(BEHIND DOOR)
Top View
Control Panel
The UH200D may be used with a wide variety of microphones.
The 3-pin XLR connector on the UH200D allows the transmitter
to be used with any dynamic microphone, as well as many two
wire positive bias lavaliere systems (such as those systems
supplied by Lectrosonics).
POWER SWITCH
Turns the battery power on and off. Even when the switch is
turned off or on abruptly, the pilot tone muting system prevents
“thumps” or transients from occurring.
The PHTM (center) position of the power switch turns on the
phantom power while the NO PHTM (fully on) position disables
phantom power. Be careful to use the center position phantom
power only when necessary and keep the voltage selector switch
in the 5 Volt position for additional protection against accidents.
PHANTOM POWER VOLTAGE SELECT SWITCH
This switch selects from three voltages when the PWR switch is
in the mid position. The voltages are:
• 5 Volts for lavaliere microphones,
• 15 Volts for some professional mics requiring high current and
for many common stage mics that will operate over a wide
phantom voltage range of 12 to 48 Volts. With the proper
adapter, this position can also be used with T power microphones. See our web site for details on finding or making the
proper adapter.
• 42 Volts for microphones that do in fact require a supply
greater than 15 Volts. (See below for a discussion of why 42
and not a “true” 48 Volts.)
For longest battery life use the minimum phantom voltage necessary for the microphone. Many stage microphones regulate the
48 Volts down to 10 Volts or so internally anyway, so you might
as well use the 15 Volt setting and save some battery power. If
you are not using a microphone for the input device, turn the
Side View
phantom power off (off is the fully up position of the power
switch). The phantom power should only be used with a fully
floating, balanced device such as almost any type microphone
with a 3 pin XLR connector. If you use the phantom power with an
unbalanced device or if pins 2 or 3 are DC connected to ground,
then you will draw maximum current from the power supply. The
UH200D is fully protected against such shorts but the 9 Volt
battery will be drained at twice its normal rate.
The transmitter can supply 4 mA at 42 Volts, 8 mA at 15 Volts,
and 8 mA at 5 Volts. The 42 Volts setting actually supplies the
same voltage to a 48 Volt microphone as the DIN standard
arrangement due to a dynamic biasing scheme that does not
have as much voltage drop as the DIN standard. The 48 Volt DIN
standard arrangement protects against shorts and high fault
current with high resistance in the power supply feeds to pins 2
and 3. This protects the supply if the supply current is accidentally shorted to ground and also keeps the microphone from
being attenuated by the power supply. The UH200D improves on
those functions and is able to use less power from the battery by
using constant current sources and current limiters. With this
dynamic arrangement the UH200D can also supply more than
twice the current of competing 48 Volt plug on units and provide
4 times the current to some very high end 15 Volt microphones.
The 5 Volt setting is provided for lavaliere microphones made by
us and others. Do not power lavalieres from the 15 or 48 Volt
setting as the microphone will be most likely destroyed.
Lectrosonics makes an adapter, MCA5X, that will adapt our
standard TA5F 5 pin microphones to the UH200D. This adapter
also provides protection against excessive phantom voltage. If
voltages higher than 5 Volts are applied to the adapter, a Zener
will shunt excess voltage to ground. The microphone won't work
until the voltage is correctly reduced to 5 Volts. If you have an
older lavaliere mic that was wired directly to an XLR for use with
the earlier UH200's, we strongly recommend building our protection circuit into the XLR to prevent accidental destruction of the
lavaliere.
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