Portable Display FM Transmitter (863 MHz)
LT-700-863

Highlights

  • Superior Audio Quality – 70 dB signal-to-noise ratio, setting the industry’s sound quality standard.
  • A choice between 17 channels, complete antenna and accessory options make Listen products ideal for a wide range of applications.
  • Look & Listen™ LCD shows channel, battery status, and programming information.
  • 100 % Digital – Listen receivers are digitally-tuned so transmission won’t drift; assurance that when you select a channel, it stays on the channel.
  • Transmit up to eight (8) channels simultaneously on 863 MHz.
  • Uses standard alkaline or NiMH batteries.
  • Transformer charging plug or drop in charging contacts.
  • Built in SmartCharge™ won’t allow batteries to overcharge. Charging circuitry is conveniently built into Listen’s LT-700 Transmitter; never worry about unplugging a transformer at a certain time.
  • Mute switch.
  • Mic and/or line level inputs.
  • Limited Lifetime Warranty with hassle-free support.

Includes

LT-700 Portable Display FM Receiver
Quick Reference Card (863 MHz)
Limited Lifetime Warranty Program Card (863 MHz)
FM System Design Guide and Manual Card (863 MHz)

Architectural Specs

The portable FM Transmitter shall be capable of broadcasting on 17 channels. Channel tuning shall be capable of being locked. The transmitter shall have a SNR of 70 db or greater. The output power shall be adjustable to quarter, half or full. The device shall have an audio frequency response of 50 Hz to 15 kHz, +/-3db. The device shall incorporate a microphone sensitivity switch. The device shall incorporate a mute switch. The unit shall operate off of 2 AA batteries. The battery door shall be capable of being mechanically locked. The device shall incorporate an LCD display that indicates battery level, channel, channel lock, low battery, battery charging, programming, and RF signal strength. The portable transmitter shall incorporate automatic battery charging circuitry for recharging of NiMH batteries. The Listen LT-700-863 is specified.

CAD Drawing

    • Specifications

     SpecificationsLT-700-863
    RFRF Frequency Range863.050 - 864.950 MHz
    Number of Channels17 wide band
    Number of Simultaneous Transmitters8
    Frequency Accuracy± .005% stability 32 to 122º (0 to 50ºC)
    Transmitter Stability50 PPM
    Transmission Range0 ft. (0 m) to 250 ft. (76.2 m)
    Output Power10mW maximum (adjustable)
    AntennaUses microphone cable
    Antenna Connector3.5 mm connector
    ComplianceCE, ETSI, RoHS
       
    Audio** All system specifications are wireless end to end**
    System Frequency Response50 Hz - 15 kHz (±3dB)
    System Signal to Noise Ratio70db (A-Weighted)
    System Distortion<2% total harmonic distortion (THD) at 80% deviation
    Microphone InputUnbalanced, tip of 3.5mm connector, -20 dbu nominal, -30 dbu maximum, impedance 21 ohms
    Microphone SensitivityThree position switch: high, middle, and low; 6db increments
    Line InputUnbalanced, ring of 3.5mm connector, -10dbu nominal input level, -3dbu maximum, impedance 10K ohms
    Microphone Power3VDC Bias
     
    ControlsUser ControlsPower, mute, channel UP/DOWN
    Set-up Controls (battery compartment)Mic sensitivity, NiMH/alkaline battery, SQ enable/disable
    ProgrammingChannel Lock out,Channel lock
       
    IndicatorsLEDRed, illuminated when unit is on. Flashes when batteries are low, or to indicate charging. Flashes when muted
    DisplayChannel Designation, lock status, signal strength indication, battery life, RF Power
       
     Battery TypeTwo AA batteries, alkaline or NiMH
    PowerBattery Life (Listen batteries)15 hours alkaline (LA-361), 8 hours NiMH rechargeable (LA-362)
    Battery Charging (NIMH only)Fully automatic, 13 hours
    Power Supply I/P 120VAC; O/P 7.5VDC 250 mA; Drop in contact points for use with charging cases. Power supply not included (LA-202)
    Power Supply Connector2.3mm OD by 0.7mm ID, barrel type connector 7.5 VDC, center positive <250mA. Drop in contact points for use with Listen charging cases
    Power Supply ComplianceRoHS, WEEE, UL, PSE, CE, CUL, TUV, CB compliant
       
    PhysicalDimensions (H x W x D)3.00 x 1.00 x 5.00 in. (7.6 x 2.5 x 13.0 cm)
    ColorDark Grey with white silk screening
    Unit Weight3.9 oz (111g)
    Unit Weight with batteries5.8 oz (164g)
    Shipping Weight1.0 lbs. (0.45kg)
    DoorManually Lockable. Up, down, and power buttons through door. Other controls behind door (see controls)
       
    EnvironmentalTemperature - Operation14 to 104º F (-10 to 40º C) 
    Temperature - Storage-4 to 122° F (-20 to 50° C)
    Humidity0 to 95% relative humidity, non-condensing
       
    Specifications are subject to change without notification

    Requirements

    Used With

    Accessories

    Support Documents

    • FAQ

    What is the range of the LT-700 portable transmitter?
    Line of site up to 150 ft. (45.7 m) for both 72 MHz and 216 MHz. Line of site up to 200 ft. (60.9 m) with 863 MHz.
     
    Can I have multiple transmitters operating in one facility?
    Yes. You can have multiple transmitter operating in one area on different channels, however more than one transmitter cannot be used on the same channel.
    Can I use a line source with the portable transmitter?
    Yes. Listen offers the LA-263, a mic/line input cable for this use (72 MHz & 216 MHz).
     
    How long do the batteries last on the portable transmitter?
    Alkaline batteries last 20 hours; NiMH rechargeable batteries last 10 hours (72 MHz & 216 MHz). With 863 MHz, Alkaline batteries last 15 hours and NiMH rechargeable batteries last 8 hours.
     
    Does the LT-700 provide phantom power?
    Yes, 3VDC.
     
    Will the LT-700 portable transmitter work for two-way communication?
    No. However, Listen does not recommend a two-way system for tour group applications. A two-way system means that everyone hears every sniffle, cough, comment etc. The tour guide loses control of the tour and the tour becomes unproductive.

    Troubleshooting Guide

    What is the range of this transmitter?

    • A range of up to 150 feet is achievable depending upon the following:

      • The orientation of the Microphone cord, which is the transmitting antenna.
      • The objects between the transmitter and receiver. All material, especially metal, will weaken the signal strength.
      • The type of receiver and its receiving antenna.

    What channels should I be transmitting on?

    • It is recommended that wideband channels are used for best audio quality. If transmitting multiple simultaneous channels, narrowband frequencies may be required.

    The signal being transmitted is inconsistent, my receivers cut in and out.

    • The receivers may be out of range of the transmitter.

    How do I connect my TV, VCR, CD player, etc. to this transmitter?

    • Listen provides a Line Input Cable (LA-263) that will allow you to connect an RCA connection to the transmitter.

    My microphone sounds very low in audio level.

    • Make sure that the microphone sensitivity switch, located in the battery compartment, is in the correct position. Consult the microphone users manual for the correct setting.

    What type of microphones can I use with this transmitter?

    • Any Listen condenser microphone may be used with this transmitter.

    My batteries will not charge.

    • Make sure you are using NiMH batteries.
    • Make sure the battery select switch, located in the battery compartment, is in the NiMH position.
    • Make sure that the power cord is plugged in properly.
    • If using a charging case, make sure that the transmitter is properly placed in the charging pocket.

    The batteries in my transmitter will not hold a charge.

    • It is time to replace the batteries. Listen recommends that the batteries be replaced every 3 years or after 500 charges.
    • Make sure that the transmitter is actually receiving the charge. The red LED on top of the transmitter will flash when charging.
    • Make sure that the unit is being turned off when not in use.

    When I use the mute function, the auxiliary input can still be heard.

    • The Mute function only mutes the microphone input. Any auxiliary audio input will still be transmitted.

    How do I lock out channels?

    • Enter the program mode by holding the UP and DOWN buttons simultaneously for 5 seconds. The PGM icon will appear. Once in the program mode, scroll through the channels using the UP and Down buttons. Briefly pressing the power button will toggle each channel in and out of Lockout. When the channel is locked out, the L/O will be displayed on the LCD indicating that channel is locked out.

       

     

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