Lectrosonics IFBT4 Frequency-Agile Compact IFB Transmitter

MSRP: $1,798.00
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FBT4 Frequency-Agile Compact IFB Transmitter

  • Digital Hybrid Wireless™ technology
  • 256 UHF frequencies in 100kHz steps
  • Microprocessor controlled operation
  • 250 mW power output for long range use
  • Pilot tone squelch control
  • Multi-use XLR input jack
  • Built-in microphone preamp
  • DIP switch programmable intercom input
  • Tx mute for frequency scrolling
  • Multi-function LCD display
  • Compact size for use anywhere
  • Rugged machined aluminum construction

The Lectrosonics IFBT4 UHF transmitter was designed for use in broadcast, motion picture, theater, and stage applications where extended operating range and high quality audio are essential. The IFBT4 can be used as a stand-alone device or patched directly into popular intercom systems.

Lectrosonics Digital Hybrid Wireless™ systems overcome channel noise in a dramatically new way, digitally encoding the audio in the transmitter and decoding it in the receiver, yet still sending the encoded information via an analog FM wireless link. This proprietary algorithm is not a digital implementation of an analog compandor but a technique that can be accomplished only in the digital domain, even though the inputs and outputs are analog.

Because it uses an analog FM link, Digital Hybrid Wireless™ enjoys all the benefits of conventional FM wireless systems, such as excellent range, efficient use of RF spectrum, and resistance to interference. However, unlike conventional FM systems, it does away with the analog compandor and its artifacts.

Microprocessor control provides user-friendly operation and eliminates transients at turn-on and turn-off. The transmitter output is muted in the TUNE mode to avoid generating interference in other wireless systems while scrolling up and down to change frequencies.




  • Channel Spacing: 100 kHz (0.1 MHz)
  • RF Power Output: US, X: 250 mW E01: 50 mW
  • Pilot tone: US: 25 to 32 kHz; 3.5 kHz deviation (Nu Hybrid mode) E01: 29.997 kHz; 2 kHz deviation (IFB Mode), 25 to 32 kHz (Digital Hybrid Mode X: 29.997 kHz IFB & 100 MODE, 32.765kHz 200 MODE, 400 MODE step selected
  • Spurious Radiation: US:Compliant with ETSI EN 300 422-1 v1.4.2 E01: 37 dBc above 1 GHz
  • Frequency Stability: ±.001% (10 ppm) @ 25° C 
  • Temperature Stability: ±.001% (10 ppm) from -30° C to +50° C
  • Channel Selection: Momentary pushbutton switches, TUNE Up and Down Compatibility Modes US: Mode 3, IFB and Nu Hybrid E01: IFB, Digital Hybrid Wireless (400 Series) X: Digital Hybrid Wireless(tm) 400 Series, 100 Series, 200 Series, Mode 3, Mode 6, and IFB
  • Audio Frequency Response: 100 Hz to 8 kHz, ±1 dB, IFB mode system response (see Rolloff) 30 Hz to 20 kHz, ±1 dB, Nu Hybrid mode system response
  • Rolloff: Low frequency audio rolloff is Menu selectable for 3 dB down at 35 Hz or 50 Hz.
  • Signal to Noise Ratio: 90 dB typical (“A” weighted)
  • Output Impedance: 50 ohms
  • Audio Input Levels: • 0 dBu for Line, RTS1 & RTS2 • -10 dBu for Clear Com • -42 dBu for mic dry inputs (no phantom power) • +/-50Vdc max
  • Audio Input Config: Balanced and Unbalanced, rear panel selectable for Line, Mic. RTS 1, RTS 2, and Clear Comm
  • Audio Input Impedance: Greater than 2 K balanced, greater than 1 K unbalanced at any gain setting
  • Gain Control Range: -18 dB to +24 dB (0 dB nominal center), Menu selectable
  • Audio Input Jack: Standard XLR female connector
  • Input Power: 12 to 14 VDC typical, 200 ma. max.; Max. Input Range 6 to 18 VDC
  • Power Input Jack: Coax type, locking LZR RL26AE
  • Indicators: Backlit Liquid Crystal Display. Displays modulation meter, frequencies, modes, rolloff, audio level, and tuning groups.
  • Front panel controls: • MENU momentary pushbutton switch • Power OFF-TUNE-XMIT, 3 position slide switch • Select UP momentary pushbutton switch • Select DOWN momentary pushbutton switch
  • Rear panel controls: Input Mode Select, 4 section DIP switch
  • Weight: 9.6 ozs. (272 grams)
  • Size: 5.25” L (including connectors) x 3.25” W x 1.25” H 133.35 L (including connectors) x 82.55 W x 31.75 H mm
  • Emission designator: 110KF3E
    Specifications subject to change without notice.