72 MHz or 216 MHz for Assisted Listening Devices


72 – 75 MHz vs. 216 MHz

Each frequency band has different advantages over the other. Consider the following questions to help determine the right frequency for your particular application:

  1. Do I have a very long range that needs to be covered?
  2. Is distance of transmission a top priority?
  3. Is there a need to use more than (3) three frequencies simultaneously?
  4. Is audio quality a main concern?
  5. If using an external antenna, what is the clearance space with the ceiling?
  6. Is the transmission going to be used primarily outdoors?
  7. What length of cable will be used from the transmitter to the antenna?
  8. Which frequency is less likely to have interference with other signals?

Answering these questions will give you a better idea of which frequency will best suit your application. Here are a few facts and details about the two frequencies:

Transmission Range

The transmission range doubles when using the 216 MHz frequency band. Using a dipole antenna (more efficient) the 72 MHz frequency has a transmission range of 1,500 ft. (457 m). With the same scenario 216 MHz will broadcast up to 3,000 ft. (914 m) line of site. In portable applications, using the LT-700 Portable Display FM Transmitter, the range is the same with both frequencies – 150 ft (45.7 m).

Simultaneous Channels

Because the 72 MHz band is larger, up to (6) six channels can be used simultaneously, while only (3) three channels can be used concurrently with the 216 MHz band.

via Blog – Should I Use 72 MHz or 216 MHz? – Listen Technologies.

Good info I needed today while working on an AV specification.

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About Matthew Peterworth

I currently work as a Technology Specialist at Henderson Engineers in Kansas City – a Mechanical-Electrical-Plumbing (MEP) design firm. Prior to that I was a Project Manager for Information Technology Services (ITS), the central IT department at the University of Texas at Austin. As of July 2008 I am a Registered Communications Distribution Designer (RCDD) through BICSI. And as of June 2011 I am a licensed Professional Engineer (PE) in the great state of Texas. Please follow me on Twitter @mpeterworth. https://twitter.com/mpeterworth

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