The Retekess TR506 is a portable FM transmitter with four selectable RF output levels. It accepts microphone and line-in audio simultaneously and transmits on any frequency across the 76–108 MHz FM band. Compatible FM receivers tuned to the same frequency receive the audio, making the TR506 suitable for presentations, guided tours, simultaneous interpretation, and other lawful local audio distribution applications.

Important — regulatory notice: Radio-frequency transmission is regulated. The TR506 offers adjustable RF output levels and must only be operated on frequencies and at power levels permitted by the regulations applicable in the country of use. UK users should confirm the appropriate Ofcom authorisation before transmitting.

Key Features

• Adjustable RF output — four power levels
  • Level 1: 0.01 mW — manufacturer reference range approximately 10 m
  • Level 2: 10 mW — manufacturer reference range approximately 100 m
  • Level 3: 100 mW — manufacturer reference range approximately 300 m
  • Level 4: 200 mW — manufacturer reference range approximately 400 m

  Reference ranges are open-area figures provided by Retekess. Actual range depends heavily on environment, antenna placement, obstructions, and interference.

• 76–108 MHz FM tuning — manual frequency adjustment in 100 kHz steps; frequency stability ±10 PPM
• Dual audio inputs — separate 3.5 mm microphone jack and 3.5 mm line-in jack; both can be used simultaneously; microphone and line-in levels independently adjustable
• Included lavalier microphone — 1.2 m cable lavalier microphone supplied for hands-free presentation
• Stereo / mono switching — one-button selection between stereo and mono output
• Keyboard lock — one-button lock and unlock to prevent accidental frequency or level changes during use
• Battery level indicator — on-device display shows remaining charge at all times
• Rechargeable BL-5C battery — 3.7 V / 1000 mAh Li-ion; standard BL-5C form factor (user-replaceable); charges via Mini USB at 5 V; charging time approximately 5 hours
• Compact and lightweight — 82 × 60 × 22 mm (excluding antenna); approximately 67 g (excluding battery)

Approximate Battery Life by Power Level

• Level 1 (0.01 mW): approximately 16 hours
• Level 2 (10 mW): approximately 10 hours
• Level 3 (100 mW): approximately 8 hours
• Level 4 (200 mW): approximately 5 hours

Battery life figures are manufacturer reference values. Actual working time will vary with use conditions.

Ideal Applications

• Guided tours — guide speaks into the TR506; participants listen on compatible FM receivers tuned to the same frequency
• Simultaneous and consecutive interpretation
• Teaching, lectures, and presentations
• Factory and site visits
• Conference and seminar audio distribution

Technical Specifications

• FM frequency range: 76–108 MHz
• Frequency step: 100 kHz
• Frequency stability: ±10 PPM
• RF output levels: 0.01 mW / 10 mW / 100 mW / 200 mW (4 selectable levels)
• Audio inputs: 3.5 mm microphone jack; 3.5 mm line-in jack (simultaneous use supported)
• Stereo / mono: one-button switching
• Keyboard lock: yes
• Frequency response: 50 Hz–15 kHz
• Signal-to-noise ratio: ≥60 dB
• Total harmonic distortion: ≤0.2%
• Battery: BL-5C Li-ion 3.7 V / 1000 mAh (user-replaceable)
• Charging: Mini USB, 5 V; charging time approximately 5 hours
• Dimensions: 82 × 60 × 22 mm (excluding antenna)
• Weight: approximately 67 g (excluding battery)

What’s Included

• 1 × TR506 FM Transmitter
• 1 × FM Antenna
• 1 × BL-5C Li-ion Battery (3.7 V / 1000 mAh)
• 1 × Car Charger (5 V / 1000 mA output)
• 1 × Lavalier Microphone (1.2 m cable)
• 1 × 3.5 mm Male-to-Male Audio Cable
• 1 × USB-to-Mini USB Charging Cable