Decade LX-75 series User manual

1
HI-FI MONO/ STEREO FM TRANSMITTERS
LX-75 Series
INSTRUCTION MANUAL
Canada: Operation of this device is subject to the following condition: This device is
certified under the RSS-123 regulation. A permit or license from Industry
Canada could be required. Please consult your nearest Industry Canada
bureau for more details.
USA: Operation of this device is subject to the following condition: This device is
not certified with the FCC and shall not be sold or used in United States.
1001-75
DECADE

2
TABLE OF CONTENT
PAGE
SECTION 1: GENERAL INFORMATIONS 3
A) Introduction …..……………………………………………. 3
B) Description ………………………………………………… 3
C) Warranty …………………………………………………… 3
D) Warning ……………………………………………………. 3
E) Technical specifications ………………………………….. 4
SECTION 2: INSTALLATION 4
A) Introduction ………………………………………………… 4
B) Receiving inspection ……………………………………… 4
C) Connections ………………………………………………. 4
D) Location of the transmitter……………………………….. 5
SECTION 3: OPERATION 5
A) Controls and indicators…………………………………… 5
B) Input and output connectors…………………………….. 5
C) Optimal input level ………………………………………… 5
SECTION 4: MAINTENANCE AND PROGRAMMING 6
A) Maintenance ………………………………………………. 6
B) Frequency programming …………………………………. 6
C) RF power level programming …………………………… 6
SECTION 5: APPLICATIONS 7
SECTION 6: PROGRAMMATION CODES TABLES 8
A) Frequency programming ………………………………… 8
B) RF power level programming …………………………… 9
APPENDICES LX-75 series technical specifications........................ 10
Front & back panel description…………………………… 11
Telescopic antenna length adjustment ………………….. 12

3
SECTION 1
GENERAL INFORMATIONS
A) Introduction
Thank you for purchasing one of the fine products made by DECADE transmitters.
Your new LX-75 series HI-FI FM TRANSMITTER is a very high performance and high
reliability piece of equipment. Before using it, please read this manual carefully in order
to obtain the best possible results from your transmitter. The manual contains
installation, operation and programming procedures for DECADE LX-75 series FM
Transmitters.
B) Description
LX-75 series transmitters include a high precision crystal controlled VCO and an RF
power amplifier. The LX-75 series are offered in 3 different audio configurations. The
LX-75M (mono) accepts audio signals via the rear panel 1/4 female jack and an
additional balanced 600 Ohms XLR-3 type with phantom power input jack
(microphone level) and an additional audio level control via the front panel. The LX-
75B (mono) accepts audio signals via the rear panel 1/4 female jack and is equipped
with an additional balanced 600 Ohms XLR-3 type input jack (line level) and an
additional audio level control on it's front panel. The LX-75SM shares the same type
of audio inputs as the LX-75M but does broadcast in stereo or mono mode.
Each input types are associated to an individual volume control on the front panel in
order to get optimum modulation level. This useful feature makes Decade transmitters
very versatile, allowing them to accept audio signals from many sources like: CD or
DVD players, tape deck, microphones and audio mixing boards (please refer to section
3-c for optimum audio broadcasting)
C) Warranty
LX-75 series transmitters come with a one (1) year warranty that covers parts
replacement and labor required to repair any defects resulting from the manufacturing
process. All claims must be authorized by DECADE prior to shipment of a faulty unit
for repairs and a copy of the invoice must be included in the shipment. Shipping fees
are assumed by the client and DECADE will pay for the return of the repaired unit.
D) Warning
DECADE transmitters operate on the 88.1 MHz - 107.5 MHZ commercial FM
broadcast band, so signals transmitted by them can be received on any standard FM
receiver. Thus, some care should be taken in the use made out of these transmitters.

4
DECADE transmitters inc. is not responsible for any loss of profit or
laws violation during the utilisation of their transmitters.
Industry Canada legislate the use of FM transmitters for Canada uses.
The LX-75 series are not certified by the FCC so it is not legal to sell or use these
products in USA.
E) Technical specifications
Refer to appendices, Technical specifications of LX-75 series.
SECTION 2
INSTALLATION
A) Introduction
Installation of a DECADE FM transmitter includes the following steps: 1) receiving
inspection; 2) mounting in a rack or on a shelf; 3) connection of the AC supply and
audio source; location, installation and connection of the antenna (optional).
B) Receiving inspection
Check the transmitter packaging for any damage that could have occurred in the
shipping. If you find any damage on the transmitter, keep the packaging for claiming
purposes with the freight company. Any damage should be noted on the receiving slip
at the time of delivery and the freight company advised within 5 workable days
following the delivery of damaged units.
C) Connections
After installation of the transmitter in a rack or on a shelf, plug the AC wall adaptor
(furnished) in the AC receptacle on the back panel, of the transmitter and connect the
wall adaptor to a 120 V, 60 Hz wall AC socket. An RCA audio cable is also furnished
for linking your audio source to the LX-75 audio inputs.

5
D) Location of the transmitter
DECADE transmitters are designed for indoor or outdoor use in a dry environment, in
temperatures ranging from -50 to 50 C. In order to obtain optimum performances, it
is recommended to place them far from any electromagnetic noise source
(transformers, motors, etc.).
SECTION 3
OPERATION
A) Controls and indicators
The Input level is controlled by an associated potentiometer, located on the front
panel. A power indicator and an over modulation led are also located on the front
panel of the LX-75 series
B) Input and output connectors
The LX-75 series are offered in five different audio configurations, so inputs type may
vary from one model to the other. Please refer to section 1-B (page 2).The LX-75
series RF output signal is either routed to a fixed telescopic or an SO-239 (UHF female
type) connector that enables the transmitter’s RF output to be linked to a remote FM
antenna (Decade model # GP-32 or LGP-FM) that is optional. The use of a remote
antenna usually produces a better coverage when compared to the fixed telescopic
antenna.
C) Optimal input level
Optimal input level is reached when the OVER modulation indicator remains off at all
time. Adjust the input level control to meet that condition. To obtain this result it is
mandatory to compress the audio input signal (between your audio source output and
the inputs of the transmitter inputs. The over modulation LED on the front panel shall
never or rarely lit up. The level has to be adjusted in a manner to avoid over
modulation.

6
SECTION 4
MAINTENANCE AND PROGRAMMING
A) Maintenance
No maintenance is required to keep the transmitter in top operating condition. If an
external cleaning appears necessary, use a soft, damp cloth and mild soap only.
B) Frequency programming
The transmitting frequency is user programmable via a set of 2 Hex switches that are
labeled « F1 and F2 » on the rear panel (All models).Your LX-75 is factory preset to
98.5 MHz when shipped.
1) From the Hex switches code table (page 8), select the appropriate Hex switch code
for your chosen FM frequency and set the hex switches accordingly.
Important: The LX-75SM models are equipped with an additional Bit switch that is
labeled « ST » that allows to broadcast in mono or stereo mode. Stereo mode is
activated when the ST switch is in ON position. Also included is an additional Bit
switch that is labeled « BB » that allows to add a bass boost of 6dB in the audio
spectrum contained between 0 Hz to 100Hz.Bass boost mode is activated when
the BB switch is in ON position.
Important notes :
1) The frequency range of the LX-75 series is 88.1MHz to 107.5MHz
2) If your application requires more than one LX-75, it is mandatory to leave some
space between the two chosen frequencies in a manner to avoid channel
scrambling or intermodulation products. Ex; If the first chosen FM frequency is 88.5
MHz then nearest the second chosen FM frequency shall be 89.1 MHz. The chosen
FM frequencies shall never interfere with local FM broadcast stations.
C) RF power level programming
With the help of the Hex switches labeled « P1 P2 » it is possible to digitally program
the RF output in increments of 5 miliWatts. Please refer to the Hex codes on page 9.
The power range of the LX-75 series is: 0 miliWatt up to 80 miliWatts. Your LX-75 is
factory preset to 80 miliWatts when shipped.

7
SECTION 5
APPLICATIONS
Applications for DECADE transmitters are almost unlimited, but here are a few very popular
ones. With DECADE transmitters, a whole new world opens up for hearing impaired people,
and most of all for people demanding the best sound reproduction possible, regardless of the
environment.
CHURCHES: Connected to the church sound system, the transmitter
broadcasts the oral and musical content of the celebrations to
the attendants, hearing impaired or not, and let them benefit
from a perfect listening.
CINEMAS: Connected to the Dolby cinema processor or projector
preamplifier, the transmitter allows the attendants to enjoy the
full stereo spectrum and all the details of the soundtrack of the
movie. A truly unique experience everyone must try.
THEATRES: With two microphones installed on the stage and fed to the
transmitter through a mixing board, you will have the sensation
of being seated right next to the actors, even if you are actually
seating in the last row.
CONFERENCE HALLS: Many transmitters can be used as part of a simultaneous
translation scheme, where attendants can listen to the
conference in the language of their choice. A single transmitter
can also be used as an aid for hearing impaired persons.

8
FREQUENCY PROGRAMMING CODES TABLE
Freq
MHz
F1 F2 Freq
MHz
F1 F2
- - - 97.9 1 6
88.1 4 7 98.1 1 5
88.3 4 6 98.3 1 4
88.5 4 5 98.5 1 3
88.7 4 4 98.7 1 2
88.9 4 3 98.9 1 1
89.1 4 2 99.1 1 0
89.3 4 1 99.3 0 F
89.5 4 0 99.5 0 E
89.7 3 F 99.7 0 D
89.9 3 E 99.9 0 C
90.1 3 D 100.1 0 B
90.3 3 C 100.3 0 A
90.5 3 B 100.5 0 9
90.7 3 A 100.7 0 8
90.9 3 9 100.9 0 7
91.1 3 8 101.1 0 6
91.3 3 7 101.3 0 5
91.5 3 6 101.5 0 4
91.7 3 5 101.7 0 3
91.9 3 4 101.9 0 2
92.1 3 3 102.1 0 1
92.3 3 2 102.3 0 0
92.5 3 1 102.5 F F
92.7 3 0 102.7 F E
92.9 2 F 102.9 F D
93.1 2 E 103.1 F C
93.3 2 D 103.3 F B
93.5 2 C 103.5 F A
93.7 2 B 103.7 F 9
93.9 2 A 103.9 F 8
94.1 2 9 104.1 F 7
94.3 2 8 104.3 F 6
94.5 2 7 104.5 F 5
94.7 2 6 104.7 F 4
94.9 2 5 104.9 F 3
95.1 2 4 105.1 F 2
95.3 2 3 105.3 F 1
95.5 2 2 105.5 F 0
95.7 2 1 105.7 E F
95.9 2 0 105.9 E E
96.1 1 F 106.1 E D
96.3 1 E 106.3 E C
96.5 1 D 106.5 E B
96.7 1 C 106.7 E A
96.9 1 B 106.9 E 9
97.1 1 A 107.1 E 8

9
97.3 1 9 107.3 E 7
97.5 1 8 107.5 E 6
97.7 1 7 - - -
- - - - - -
POWER LEVEL PROGRAMMING CODES TABLE
RF Power
miliWatts
P1
(HI)
P2
(LO)
RF Power
milliwatts
P1
(HI)
P2
(LO)
0 0 0 35 A 3
1 1 F 40 B 0
2 2 8 45 B B
3 3 0 50 C 6
5 3 D 55 D 0
10 5 6 60 D A
15 6 9 65 E 4
20 7 A 70 E D
25 8 9 75 F 6
30 9 7 80 F F

10
TECHNICAL SPECIFICATIONS
LX-75 SERIES
RADIO SECTION (All models):
MODULATION: FM, deviation of 75 kHz
FREQUENCY RANGE: from 88.1 to 107.5 MHz (digitally programmable)
FREQUENCY PRECISION: 0.005% or better (-50 degC to +50degC)
HARMONICS REJECTION: 40 dB min., 45 dB typ (second harmonic).
OUTPUT POWER: 0 miliWatt to 50 miliWatts (digitally programmable)
LOAD IMPEDANCE: 50 Ohms typ.
ANTENNA CONNECTOR: Fixed telescopic antenna or UHF-F (SO-239 type)
NOTIFICATION STANDARD: Industry Canada RSS-123 (Certification)
CERTIFICATION ID NUMBER: CAN 1857 231 158 (RSS-123)
CONTROLS & INDICATORS: Frequency selection, Power selection
AUDIO SECTION:
MODE: mono (HI-FI): (LX-75B, LX-75M)
stereo (HI-FI): (LX-75SM)
FREQUENCY RESPONSE: 20 Hz - 20 000 Hz, @-1dB (LX-75B, LX-75M)
20 Hz - 15 000 Hz, @-1dB (LX-75SM)
TOTAL HARMONIC DISTORTION: 0.05% max (All models)
SIGNAL TO NOISE RATIO: 70 dB min. (All models)
DYNAMIC RANGE: 80 dB min. (All models)
STEREO SEPARATION: 35dB Min, 45dB Typ (LX-75SM)
INPUT SENSITIVITY: -15dBm to +15dBm, 6K Ohms (unbalanced line level 1/4 female jack) (All models)
- 9dBm to +21dBm, 600 Ohms (balanced line level XLR-3 jack) (LX-75B model)
-50 dBm to -10dBm, 950 Ohms (balanced mic level XLR-3 jack) (LX-75M, LX-75SM models)
PHANTOM POWER: +15 Volts DC (Open load) (LX-75M, LX-75SM models)
MISCELLANEOUS:
POWER REQUIREMENTS: 115 V/16Vac, 60 Hz @ 500 mA (AC wall adaptor: furnished)
DIMENSIONS: 7.8" (19.81 cm) large, 12" (30.48 cm) deep, 1.85" (4.70 cm) high
WEIGHT: 8 lb (3.63 kg)
DECADE Transmitters reserves the right to make changes or improvements in manufacturing or design of its products, witch may affect
specifications. All rights reserved 2004.

11
FRONT & BACK PANEL DESCRIPTION
1. POWER: Indicates that the AC power has been activated.
2. OVER: Indicates over modulation (100% and more).
3. LINE LEVEL: Controls the audio level that is applied to the line inputs jack.
4. MIC./BAL. LEVEL: Controls the audio level that is applied to the Mic/Bal input jack.
5. MIC./BAL. INPUT: The audio input (low impedance balanced input).
6. AC input: This is where you plug the AC adaptor (furnished with the transmitter).
7. AC power switch: Turn the power unit on or off.
8. RF POWER: Power programming switch.
9. BB: When activated, the bass boost switch enables a circuitry that will produce a 6dB gain from
20Hz to 150Hz.
10. ST: When activated, the stereo switch enables a digital circuitry that will produce stereo
broadcasting.
11. FREQUENCY SELECT: Frequency programming switch.
12. LINE INPUTS: The audio inputs signals (high impedance unbalanced inputs).
13. The transmitting telescopic antenna.

12
Telescopic antenna length adjustment.
In a manner to achieve good performances (more coverage distance) with your Decade FM
transmitter, it is mandatory to adjust the length of the telescopic antenna to it’s associated
frequency.
Procedures:1) Choose a free frequency (see Frequency selection page 5).
2) Take note of the associated length (ex: 88.5MHz = 35 inches).
3) With the help of a measuring tape or ruler; extend the telescopic antenna in a
manner to obtain the desired length (from base to tip of antenna).
Frequency
MHz Rod length Inches Frequency MHz Rod length Inches Frequency MHz Rod length Inches Frequency MHz Rod length Inches
88.1 35 93.3 32 98.5 29 1/2 103.7 27 1/2
88.3 35 93.5 32 98.7 29 1/2 103.9 27 1/2
88.5 35 93.7 32 98.9 29 1/2 104.1 27 1/2
88.7 35 93.9 32 99.1 29 1/2 104.3 27 1/2
88.9 35 94.1 31 1/2 99.3 29 1/2 104.5 27
89.1 35 94.3 31 1/2 99.5 29 104.7 27
89.3 35 94.5 31 1/2 99.7 29 104.9 27
89.5 35 94.7 31 1/2 99.9 29 105.1 27
89.7 35 94.9 31 100.1 29 105.3 27
89.9 35 95.1 31 100.3 29 105.5 27
90.1 35 95.3 31 100.5 29 105.7 27
90.3 35 95.5 31 100.7 28 1/2 105.9 27
90.5 35 95.7 31 100.9 28 1/2 106.1 26 1/2
90.7 35 95.9 31 101.1 28 1/2 106.3 26 1/2
90.9 34 1/2 96.1 30 1/2 101.3 28 1/2 106.5 26 1/2
91.1 34 1/2 96.3 30 1/2 101.5 28 1/2 106.7 26 1/2
91.3 34 96.5 30 1/2 101.7 28 106.9 26 1/2
91.5 34 96.7 30 1/2 101.9 28 107.1 26 1/2
91.7 33 1/2 96.9 30 1/2 102.1 28 107.3 26
91.9 33 97.1 30 102.3 28 107.5 26
92.1 33 97.3 30 102.5 28 107.7 26
92.3 33 97.5 30 102.7 28 107.9 26
92.5 32 1/2 97.7 30 102.9 28 *108.1 26
92.7 32 1/2 97.9 30 103.1 28 *108.3 26
92.9 32 98.1 30 103.3 27 1/2 *108.5 26
93.1 32 98.3 30 103.5 27 1/2 *108.7 26
(*) Available in Asia & Europe only.
DECADE TRANSMITTERS Inc.
3480 Du Renard street, Sherbrooke, Quebec, Canada J1H 0C7
Tel: [phone], Toll free: 888-428-4323, http://www.decade.ca