Rolls HR70 FM Digital Transmitter

Rolls HR70 FM Digital Transmitter

  • $179.99
    Unit price per 

The HR70 is a digital FM transmitter. Send a signal to the XLR or RCA inputs of the HR70. Select what frequency you would like to broadcast those signals on (87.5 to 108 MHz) and you are now sending signals via FM radio. The HR70 also has a talk over circuit built in. This 1/4 watt transmitter will send an FM tramsission to any FM receiving device up to 100 feet in distance indoors. A small antenna is included.

FM radio waves, like light waves, travel in a straight direction unless reflected off objects in their path. Because of this, two sets of waves reach your antenna from the FM station; those that have traveled directly to the antenna, and those that have been reflected off buildings or mountains. When the antenna receives both kinds of signals, the two interfere with each other and result in distorted sound and poor separation. This phenomenon is called "multipath reflection". To reduce this problem, select an FM receiving device that has an antenna with good directivity and place it in the best location with strong reception.

HR70 Features:
DISPLAY: LCD display showing the active information relevant to the current operation of the HR70.
MIC/LINE: When pressed in, the gain of the XLR Mic In is reduced by 30 dB.
CLIP: LED for indication of when the circuit is over driven/clipping.
MUTE: When pressed unit will MUTE.
LEVEL: Adjusts the level of output.
FREQUENCY UP / DN: Selects the frequency that the HR70 is transmitting.
RELEASE TIME: Adjusts the amount of time for the "ducked" signal to return to its normal level. Counterclockwise; slow - Clockwise; fast.
MIC LEVEL: Adjusts the amount of gain for the Mic In circuit.
DUCK SENSITIVITY: The Threshold at which "ducking" begins. When the microphone level reaches the threshold, the signal present at the Line In jacks is reduced until the announcement is over, then the Line In signal returns to its previous level.

I/O Connectors:
Aux In: RCA L/R The Aux in is an input that will talk over the Line In (Main input)
Line in: RCA L/R This is the main line level input to the HR70.
Outputs: RCA stereo outputs.
Mic: XLR microphone input.
USB: The USB can be used to power the HR70.
ANTENNA: Connects to the included FM transmitting antenna.


  • Simple way to broadcast signals over FM
  • Clean simple design
  • All metal chassis
  • Included DC power supply


  • Frequency Response: 20 Hz - 12.5 kHz
  • Input Impedance: 100Kω Unbalanced, 600ω Balanced
  • Indicators: Power LED and Clip LED
  • Input/Output jacks: XLR balanced INPUT RCA unbalanced input and output
  • Power: 12 - 15 VDC 500mA 5 x 1.2 mm DC Jack - Center Negative
  • Transmitter Output Power: 40mw
  • Antenna Jack: BNC
  • Antenna Impedance: 75ω
  • Current: 150 mA
  • Tuning Range: 87.5 - 108 MHz
  • Dimensions: 6.75"w x 4.25"d x 1.6"h

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