Lectrosonics DHu Users Manual
DHu
Digital Handheld Transmitter
INSTRUCTION MANUAL
Rio Rancho, NM, USA
www.lectrosonics.com
DHu
Table of Contents
General Technical Description ........................................... 3
Microphone Capsules: ........................................................4
Mechanical Assembly .........................................................4
Battery Installation .............................................................. 5
Control Panel .......................................................................5
Setup and Adjustments ...................................................... 6
Powering On ...................................................................... 6
Powering Off ...................................................................... 6
Standby Mode .................................................................... 6
Power Menu ....................................................................... 6
Navigating Menus and Screens ......................................... 7
Menu Map ............................................................................. 7
Input Gain Adjustment ........................................................ 10
Programmable Switch Functions ....................................... 10
Parts and Accessories ........................................................ 12
Mic Capsule Adjustments ................................................... 13
(EXPERT LEVEL ADJUSTMENT) ..................................... 13
Specifications ...................................................................... 14
Wireless Designer Software .............................................. 14
Firmware Update Instructions ............................................ 14
Troubleshooting ................................................................... 15
Service and Repair .............................................................. 17
Returning Units for Repair ................................................. 17
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LECTROSONICS, INC.
General Technical Description
Digital Hand Held Transmitter
Introduction
The transmitter benefits from a fourth generation
design with specially developed, high efficiency digital
circuitry for extended operating time on two AA batteries. The transmitter can tune across the UHF television
band from 470.100 to 607.950 MHz, with a selectable
output power of 25 or 50 mW. The pure digital architecture enables AES 256-CTR encryption for applications
that require high level security.
Input Gain Range and Limiter
45 dB range of input gain adjustment allows gain
settings to accurately match the user’s voice and the
varying sensitivity of different microphone capsules. A
DSP-controlled analog audio limiter is employed before the A-D converter. The limiter has a range of more
than 30 dB for excellent overload protection. A dual release envelope makes the limiter acoustically transparent while maintaining low distortion. It can be thought
of as two limiters in series, a fast attack and release
limiter followed by a slow attack and release limiter.
The limiter recovers quickly from brief transients, with
no audible side effects, and also recovers slowly from
sustained high levels to keep audio distortion low while
preserving short term dynamics.
Frequency Selection
Operating frequency is normally selected using a
receiver or analyzer to assess signals in the local environment to avoid interference. Once an interferencefree frequency is identified, the transmitter frequency is
set to match the receiver.
The LCD on the transmitter displays frequency in MHz
and with a two character hex code that is used on
most Lectrosonics receivers.
Antenna
A unique helical antenna allows the transmitter to be
held in any position, since the user’s hands have little
or no effect on the RF output power.
Microphone Capsules
The transmitter is available from Lectrosonics with
the HHC and HHVMC cardioid condenser capsules.
Capsules from several other manufacturers are also
available for use with the HH: those with a 1.25” x 28
thread pitch and three contact rings. Condenser or
dynamic microphone capsules can be used to suit the
user’s preference or the application.
Encryption
When transmitting audio, there are situations where
privacy is essential, such as during professional
sporting events, in court rooms or private meetings.
For instances where your audio transmission needs
to be kept secure, without sacrificing audio quality,
Lectrosonics introduces Encryption Keys. Truly entropic encryption keys are first created by a Lectrosonics
receiver, such as the DSQD Receiver. The key is then
synced with the DHu via the IR port. The audio will
be encrypted and can only be listened to if both DHu
and receiver have the matching encryption key. If you
are trying to transmit an audio signal and keys do not
match, all that will be heard is silence or white noise.
IR (infrared) Sync
An IR Sync Port is used for quick setup with receivers
that offer this feature. Settings for frequency, step size
and compatibility mode are transferred from receiver to
transmitter via the IR ports.
Side Button Functions
A programmable switch on the side of the housing can
be configured as a mute/cough switch, a power switch
or be disabled.
USB Port for Key Transfer and Firmware Updates
The encryption key is generated in the receiver, then
transferred to the transmitter via a USB port using a
cable. This requires that the user be in direct contact
with both units, which increases the security level.
Firmware updates are enabled by simply downloading
a file and utility program from the Lectrosonics web
site, connecting the transmitter to a computer via the
USB port and running the program.
Rio Rancho, NM
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DHu
A mic capsule is
threaded onto the body
of the transmitter in the
direction shown.
Do not overtighten it.
The threaded interface is a 1.25”
diameter opening with 28 threads
per inch and three contact rings
Microphone Capsules:
Lectrosonics offers two types of capsules. The HHC is
the standard capsule and the HHVMC is the Variable
Mic Capsule which includes adjustments for Bass,
Midrange and Treble.
Mechanical Assembly
The lower housing opens by rotating
it in the direction shown. After the
threads are disengaged, pull the
housing downward until it engages
the detent that holds it open.
Do not touch the contacts between the mic capsule
and transmitter body. When necessary, the contacts
can be cleaned with a cotton swab and alcohol.
HHC Lectrosonics
cardioid electret
HHVMC Lectrosonics cardioid
electret with VariMic preamp
Along with these two models from Lectrosonics, a
variety of different capsules with a common thread
and electrical interface are available from the major
microphone manufacturers.
A list of compatible capsules is on the website at www.
lectrosonics.com listed the DHu product page.
*All product names are trademarks of their respective
owners, which are in no way affiliated with Lectrosonics.
Capsule Installation
Capsules are attached with a right-hand thread.
To remove the windscreen from the mic capsule,
line up the blue wrench (included with the capsule
head) with the flat notches on the lower threaded area
of the mic capsule.
Align flats on the wrench with flats on the capsule.
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LECTROSONICS, INC.
Digital Hand Held Transmitter
Battery Installation
To insert batteries, close the eject lever and insert the
upper contacts first (closest to the mic capsule). Polarity is marked on the label in the bottom of the battery
compartment.
Close
eject lever
to install
batteries
The contacts are very tight to prevent the batteries
from “rattling” as the transmitter is being handled. Pull
the eject lever outward to remove the batteries. The
battery tips will move outward, making them easier to
grasp.
Control Panel
Six membrane switches on the control panel are used
to set up the transmitter by navigating the menus on
the LCD and selecting the desired values.
IR Sync Port
Enter Menu and
Select Item
UP/DOWN Buttons for
Menu Item Selection
Power Button
Modulation
LEDs
Previous
Screen
Programmable switch
setup button
Pull eject lever outward to release batteries from contacts
Rio Rancho, NM
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DHu
Setup and Adjustments
Powering On
Press and hold the Power Button until a status bar on
the LCD is completed. The status bar will appear on
the LCD, followed by a display of the model, firmware
version, frequency band and compatibility mode.
Hold
for
DHu
V1.01
Rf On
When you release the button, the unit will be operational with the RF output turned ON and the Main
Window displayed.
DHu
The Main Window
RF output ON
545.400
-40
-20
0
If you release the button before the countdown is complete, the unit will turn on in the Standby mode with the
RF output turned OFF and the antenna icon will blink.
DHu
The Main Window
545.400
-40
-20
RF output OFF
0
Powering Off
Press and hold the Power Button (or the side button if
it is configured for turning the power on and off) while
the status bar on the LCD is completed. The power will
then be turned off. This can be done from any menu or
screen.
Powering
O . . .
NOTE: If the Power Button
is released before the
countdown is completed, the
unit will remain turned on
and the LCD will return to the
same screen or menu that
was displayed previously.
Standby Mode
A brief push of the keypad Power Button turns the unit
on and places it into a “standby” mode (not transmitting). Press the button and release before the status
bar completes. This allows the transmitter to be set up
without the risk of creating interference for other wireless systems that are operating in the vicinity.
A notice will appear briefly confirming that the RF output of the transmitter is turned off, followed by the Main
Window. The antenna symbol will blink as a reminder
that the RF output is turned off.
DHu
Rf
Off
545.400
-40
-20
Symbol blinks
when RF output
is turned OFF
0
Power Menu
When the transmitter is turned on, a
Resume
Pwr Off
Rf On?
Backlit
one of the menu items, then press the MENU/SEL button to confirm this action.
• Resume: Continue operating in the same condition as before.
• Pwr Off: Turns off the transmitter.
• Rf On?: Begin transmitting the RF signal, enters
another screen prompting a Yes or No answer.
• Backlit: The LCD includes a backlight that illuminates the display for easier viewing. It is set to
come on when any button on the control panel is
pressed, then stay on for 5 seconds, 30 seconds
or stay on all the time.
• About: Displays the model, firmware version,
frequency block and compatibility mode.
The unit can also be turned off from any menu or
screen on the LCD by holding the power button in
while the status bar on the LCD is completed.
brief push of the Power Button on
the keypad will reveal a menu
allowing you to choose between
Resume, Pwr Off, Rf On?, Backlit
and About.
Use the UP/DOWN buttons to select
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LECTROSONICS, INC.
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