T2 MULTI-FREQUENCY IFB BELT-PACK TRANSMITTER OPERATING INSTRUCTIONS and trouble-shooting guide LECTROSONICS, INC. Rio Rancho, NM www.lectrosonics.
TABLE OF CONTENTS INTRODUCTION ................................................................................................... 3 GENERAL TECHNICAL DESCRIPTION ............................................................. 4 CONTROLS AND FUNCTIONS ........................................................................... 6 BATTERY INSTALLATION ..................................................................................... 8 OPERATING INSTRUCTIONS ....................................................
Multi-Frequency IFB Belt-Pack Transmitter INTRODUCTION Thank you for selecting the Lectrosonics IFB T2 multi-frequency, IFB transmitter. The IFB T2 combines over 80 years of engineering experience with the very latest components, in a design that addresses the most demanding professional applica tions. The design of the IFB T2 transmitter was the direct result of numerous conversations with users, staging, and touring companies and dealers across the US.
GENERAL TECHNICAL DESCRIPTION The IFB T2 transmitters are comprised of a number of functional sub-systems as shown in the block diagram below. GENERAL The system uses 20kHz wide deviation for 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 a Motorola 33078 op amp for ultra low noise operation.
Multi-Frequency IFB Belt-Pack Transmitter PILOT TONE SQUELCH The IFB system utilizes an ultrasonic tone modulation of the carrier to operate the receiver squelch. This “pilot tone” consists of a 30kHz signal mixed with the audio signal following the microphone preamp, just after the compandor, to control the audio output muting of the receiver.
CONTROLS AND FUNCTIONS 100K E D C B A F 0 1.6M LECTROSONICS 1 2 3 4 5 9 8 7 6 E D C B A F 0 FREQUENCY 1 2 3 4 5 9 8 7 6 IFB TRANSMITTER T2 FREQUENCY ADJUST OFF ON 0 AUDIO LEVEL –20 LF ROLL-OFF ADJUST 75 Hz ANTENNA 35 150 LF ROLL OFF INPUT JACK The input on the IFB T2 accommodates virtually every lavalier, hand-held or shotgun microphone available. Line level signals can also be accommodated. Use a Switchcraft TA5F connector on the cord.
Multi-Frequency IFB Belt-Pack Transmitter Since the internal circuits are all tightly regulated and the RF output stage has a separate discrete regulator, the transmitter will continue to operate to a battery voltage of 6.5 Volts. From 6.5 Volts to 6 Volts, the transmitter will still operate, but with degraded performance.
BATTERY INSTALLATION The transmitter is powered by a standard alkaline or lithium 9 Volt battery. It is important that you use ONLY an ALKALINE or LITHIUM battery for longest life. Standard zinc-carbon batteries marked “heavy-duty” or “long lasting” are not adequate. Ni-cad rechargeable batteries will only provide 1.5 hours of operation, or less, and will run down quite abruptly. Alkaline batteries provide over 4.5 hours of operation. Lithium batteries can be used to provide up to 14 hours.
Multi-Frequency IFB Belt-Pack Transmitter 7) While speaking or singing at the same voice level that will actually be used, observe the MODULATION LEDs. Adjust the AUDIO LEVEL control knob until the LEDs begin to light. Start at a low setting where neither LED lights as you speak. Gradually, turn the gain up until one LED lights, then the other. The -20 LED lights when the audio level is about 12dB below full modulation. The “0” LED lights when the limiter begins to operate.
MICROPHONE CORD TERMINATION TA5F Connector Assembly 1 4 5 2 3 VIEW FROM SOLDER SIDE OF PINS 0.15" 0.3" Heatshrink Tubing Mic Cord Stripping Instructions Caution! Do not allow the shield wire to touch any metal part of the connector shell. The shield wire is the antenna on VHF models and poor operating range will result. Rubber Insulation Crimp Tabs Crimp Tabs Rubber Insulation Shield Wire Note: This termination is required on VHF transmitters and will still work fine on UHF transmitters.
Multi-Frequency IFB Belt-Pack Transmitter 5-PIN INPUT JACK WIRING The wiring diagrams shown on the next page represent the basic wiring necessary for the most common types of microphones and other audio inputs. Some microphones may require extra jumpers or a slight variation on the diagrams shown. Caution - When wiring the connector, do not use the connector body for any electrical connections. A common mistake is to use the connector body as an audio ground.
RF BYPASSING 2 WIRE MIC Some mics require RF protection to keep the radio signal from affecting the capsule, even though the transmitter input circuitry is already RF bypassed (see schematic diagram). 3 WIRE MIC Preferred locations for bypass capacitors SHIELD SHIELD If the mic is wired as directed, and you are having difficulty with squealing, high noise, or poor frequency response; RF is likely to be the cause.
Multi-Frequency IFB Belt-Pack Transmitter A6U UHF ANTENNA This is a full size cutting template. Lay the actual antenna on top of this drawing and cut at the mark for the desired frequency group. Install cap on end of antenna after cutting to length. Colored sleeve 20 21 22 23 24 25 26 27 29 28 30 31 33 32 Black cap Frequency Blocks Kits are shipped from the factory with caps of the various colors plus a black cap.
TROUBLESHOOTING Before going through the following chart, be sure that you have a good battery in the transmitter. It is important that you follow these steps in the sequence listed. SYMPTOM POSSIBLE CAUSE TRANSMITTER BATTERY LED OFF 1) Battery is inserted backwards. 2) Battery is dead. NO TRANSMITTER MODULATION LEDs 1) 2) 3) 4) NO SOUND (OR LOW SOUND LEVEL) 1) Transmitter not turned on. 2) Transmitter battery is dead. 3) Receiver antenna missing or improperly positioned.
Multi-Frequency IFB Belt-Pack Transmitter SPECIFICATIONS AND FEATURES Operating frequencies: 537.600 to 588.700 MHz 614.400 to 793.500 MHz Frequency selection: 256 frequencies in 100kHz steps RF Power output: 100 mW (nominal) Pilot tone: 29.997 kHz (± 2Hz); 4.5kHz deviation Frequency stability: ± 0.002% Deviation: ± 20 kHz (max) Spurious radiation: 90 dB below carrier Equivalent input noise: –126 dBV Input level: Nominal 2 mV to 300 mV, before limiting. 3V with limiting.
SERVICE AND REPAIR If your system malfunctions, you should attempt to correct or isolate the trouble before concluding that the equipment needs repair. Make sure you have followed the setup procedure and operating instructions. Check out the intercon necting cords and then go through the TROUBLE SHOOTING section in the manual We strongly recommend that you do not try to repair the equipment yourself and do not have the local repair shop attempt anything other than the simplest repair.
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LIMITED ONEYEAR YEAR WARRANTY LIMITED ONE WARRANTY The equipment is warranted for one year from date of purchase against defects in materials or workmanship provided it was purchased from an authorized dealer. This warranty does not cover equipment which has been abused or damaged by careless handling or shipping. This warranty does not apply to used or demonstrator equipment. Should any defect develop, Lectrosonics, Inc.
