The TRXFB3 is a wide-band transmitter featuring the new Zaxcom High Density (ZHD) Modulation. It’s packed full of features we invented to make your life on set the best it can be – built-in recording with timecode, ZaxNet remote control – so there’s never a need to get near talent – and crystal clear 100% digital transmission that rivals a hard wire.

You might be wondering what makes this unit special… It’s a reincarnation of a feature we had to bring back by popular demand. This single body pack transmits audio via UHF and receives an IFB audio feed received over ZaxNet’s 2.4 GHz signal at the same time. It replaces the need for talent to wear both a wireless microphone pack and an IFB receiver.

There’s also a key at the top of the transceiver that’s user programmable. Currently it can be assigned as a push to mute or a push to talk key. If you’d like it to be something else, just call the factory and we can most likely program the key to meet your specific needs.

The TRXFB3.5 covers blocks 20 through 23 (512-614MHz) and the TRXFB3.6 covers blocks 23 through 26 (596 – 698 MHz). It’s lightweight and durable, housed in a high strength, impact resistant nylon polymer casing. The FB3 has NeverClip™ for an incredible dynamic range and also utilizes Zaxcom’s battery saving feature PowerRoll™. PowerRoll™ automatically adjusts the transmitter output power based on the record status as sent via ZaxNet boosting the output power level up to 100 mW while rolling and powering down to 50 mW while on standby.

The FB3 works with ZaxNet, Zaxcom’s 2.4-GHz RF network that distributes remote control commands, timecode and IFB audio. With ZaxNet, one can remotely control transmitter settings such as gain, frequency channel selection, transport controls and output power levels. When paired with an IFB100/200 and Deva or Fusion the units can also replay audio via a timecode reference giving production sound mixers the ability to replay and remix audio, creating a virtual multi-track playback and re-record system.



ZHD transmission and spacing…

ZHD Modulation allows up to 10 channels of wireless to be operated in only 1 MHz of spectrum space. Channel spacing will vary based on the receiver you pair it with. The wireless signal is only 50 KHz wide and can be spaced as close as 100 KHz channel to channel allowing up to sixty channels of ZHD wireless in a single 6 MHz American television channel. The new modulation is ultra efficient resulting in incredible transmission range.

The ZHD transmitters are capable of running existing mono Zaxcom modulations maintaining compatibility with all currently produced Zaxcom receivers. ZHD modulation conforms to all currently proposed FCC regulations for spectrally efficient wireless transmission.

  • The FB3 paired with any Zaxcom wireless receivers in Mono or XR Modes can be spaced as close as 400 KHz channel to channel
  • The FB3 paired with any Zaxcom QRX235, QRX200 or QRX212 in ZHD 96 mode can used in dual mode and be spaced as close as 400 KHz channel to channel
  • The FB3 paired with any Zaxcom QRX235, QRX200 or QRX212 in ZHD 48 mode can used in single mode and be spaced as close as 200 KHz channel to channel (300 KHz recommended)


Protected under patent #’s: 7,711,443, 7,929,902, 9,094,636 B1, 8,835,814 B2 & 8,842,854


    • RF Modulation: Proprietary Digital Method
    • TRXLA3.5 RF Frequency Range: 512 – 614 MHz
    • TRXLA3.6 RF Frequency Range: 596 – 698 MHz
    • RF Frequency Step: 100 KHz
    • RF Bandwidth in ZHD 48 Mode: 50 KHz
    • RF Bandwidth in ZHD 96 Mode: 100 KHz
    • RF Bandwidth in XR Mode: 200 KHz
    • Channel Separation in ZHD 48 Mode: as close as 100 KHz (receiver dependent)
    • Channel Separation in ZHD 96 Mode: as close as 200 KHz (receiver dependent)
    • Channel Separation in XR Mode: 400 KHz
    • Antenna Connector: 50 Ω SSMA Female
    • Emission Designator: 180 KV2E, 100 KV2E, 50 KV2E
    • FCC Part: 74.861
    • Dynamic Range: 126 dB (Stereo model 106 dB)
    • Distortion: 0.002%
    • Frequency Response: Mode 0: 20 Hz to 16 kHz / T & M Mode 0.2 Hz to 16 kHz
    • High Pass Filter: Off or 30 to 220 Hz, Steps: 10 (6 dB Per Octave)
    • Mic Power: 3.3 VDC
    • Mic Connector: 3-Pin Micro LEMO
    • Input Range: -60 to -30 dBu
    • Mic Impedance: 6.8 k Ω
    • Clock Accuracy: 1.54 PPM (1 Frame Out in 6 Hours)
    • Timecode Type: SMPTE
    • Timecode Frame-Rates: 23.98, 24, 25, 29.97NDF, 29.97DF, 30NDF, 30DF
    • Media: MicroSD Card (Flash Memory)
    • File Format: .ZAX
    • Recording Time: Up to 216 hours on a 16GB card (using XD or ZHD modulation)
    • RF Frequency Range: 2.403 to 2.475 GHz
    • RF Modulation: Digital Spread Spectrum
    • RF Frequency Step: 0.001 GHz (1 MHz)
    • RF Bandwidth: 1 MHz
    • Channel Separation: 2 MHz
    • Sensitivity: -96 dBm
    • System Group Delay: 10 ms
    • Dynamic Range: 96 dB
    • Distortion: 0.01%
    • Frequency Response: 60 Hz to 12 kHz
    • Output Connector: 1/8” Stereo (3.5 mm)
    • Compatible HP Impedance: 32 to 200 ohms
    • Weight: 3.7 oz without Battery
    • Dimensions (H x W x D): 3.5″ x 2.4″ x .65″
    • Display: Graphic OLED
    • Power Output: 25 / 50 / 100 mW – Software Selectable
    • Battery Life: Up to 7 Hours with 2 Lithium AA at 100mW