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FM Transmitters Wireless TV sound


Wireless audio from your source device, broadcast to any FM radio receiver

Low-power FM Radio Transmitters allow you to take an audio signal from just about any audio source (CD player, tape recorder, iPod, computer, TV, VCR) and transmit the signal wirelessly to a nearby FM radio. Portable FM Transmitters offer added versatility by allowing you to go wireless just about anywhere. Plug in a portable device like an MP3 Player, iPod, PSP, Laptop, CD player or a tape player and a FM transmitter instantly makes the audio from your device available through any nearby FM radio. Plug in a headphone for silent use so you do not disturb others.

The portable models are small enough to take along in your backpack or your car, but powerful enough to cover a radius of up to 250 feet. You can be on the air almost instantly. All you have to do is insert a AA or 9V battery, (some come with AC adapters) plug in your audio source and choose a broadcast frequency. Any FM radio stations in your area will override your signal if you choose their same frequency, so you must choose an unused FM frequency in your area. There should be plenty to choose from so your broadcast will work. The FM radio spectrum is 88MHz to 108MHz on your FM dial.

FM transmitter specifications:

  • Dimensions: from very small hand-held models to table-top models
  • Freq. Range: 88-108 MHz although some models offer only a few FM frequencies   
  • Approx. Broadcast Range:  10-30 ft $$, 50-70 ft $$$, or 150-250 ft $$$$
  • Audio Input: 1/8 Stereo Mini-plug (adapter cables optional)
  • Power Supply:  AA(2) or 9V Battery (AC adapter available)
  • Stereo/Mono: stereo models are better
  • Antenna Type:  Built in or external telescoping
  • LED Freq. Display: better to have display
  • Costs: $12 to over $100. $70 should buy a very good model with all the features.

Wireless TV sound

Connect a small, inexpensive transmitter to your TV and transmit the sound across the room to a FM receiver with "earbud" earphones. Hard of hearing people have a problem with understanding speech, and are aided by use of earphones or headphones. The goal is to leave the TV speaker on in order to get the full range of sound and then use the earphones to make the speech easily understandable. 

Most TVs sold today have an output jack for sound. Sometimes it is marked "AUDIO OUT" and sometimes it is marked "LINE OUT". These jacks are used to connect to the FM transmitter in order to get the source sound out to wirelessly broadcast the sound across the room. 

The FM transmitter

There are several manufacturers that sell small mobile FM transmitters. These transmitters are designed to plug into music players and computers so the sound can be received by FM receivers in your home or car. Some FM transmitters cost very little but will broadcast only on 4 different frequencies, so you may have problems with interference from commercial FM broadcasts. Get one with a full range of selectable FM frequencies so you can choose one without local interference. 

FM transmitter from the CCRANE Company http://www.ccrane.com/ :
ccrane.com/fmtransmitters
C. Crane Company, Inc.
1001 Main Street
Fortuna, CA 95540
(800) 522-8863

The FM Transmitter uses FM radio waves to send sound from any device you choose (as long as it has a headphone jack or audio out jacks) to any nearby FM radio or stereo system. The only wire you have to connect is from the FM Transmitter to your source device. Since the transmitter works with any device that has a headphone jack, you can use it with CD players, satellite radios, and any other audio device with a headphone jack. Most people use it to send music from their computers or MP3 players to a nearby radio. Some people use the FM Transmitter as a  solution to the problem of people turning the TVs volume up too high. You plug the FM Transmitter into the TV, and send the audio to a small radio. Those people who are hard of hearing can plug in a headphone and turn the volume up but not disturb those around them. Use AC adapter or 2 AA batteries. Choose any FM frequency between 88.3 MHz and 107.7 MHz. Portable, fits in the palm of your hand. 

Weight: 5.8 oz. 
Size: 3" W x 3.5" H x 1" D
Cost from CCRANE Co.: $69.95 (Feb. 2007)


BELKIN FM Transmitter
 
This model of FM transmitter is less expensive but may not provide the range of coverage you need. Your radio may need to be within 10 ft or less. This is fine for some applications but not others.

Most FM transmitters have an input cable 3.5mm (1/8 in.) stereo plug (male). The output of the TV may be a 3.5mm headphone Jack (female) and/or left and right stereo RCA phono jacks. You  connect the transmitter to the TV. You might need a preamplifier to match the output signal level from the TV with the input requirements of the transmitter. Usually the output jack for headphones is a 3.5mm jack and the transmitter will plug right into it. 
    

Typically the output level coming from the headphone jack is enough to drive the transmitter without a preamplifier. A possible drawback might be that the TVs internal speaker may mute when you plug in the transmitter's plug. If you choose to use the TV audio output jacks marked as "line out" (usually two RCA phono jacks, one red and the other white or black), there may not be enough level to drive the transmitter and you will need a preamplifier. It depends on your model of TV. Small preamplifiers are available online and from Radio Shack and are inexpensive. 

The Receiver 

Any FM receiver that has a headphone/earphone output jack will do. A small portable AM/FM radio, a boom-box or a stereo receiver. Tune the radio to the frequency you have selected by connecting everything up, turning on the TV, and tuning the radio until you can hear the sound. Adjust the FM radio volume for your desired hearing comfort. 


  • You can adjust the volume level of your earphones with the radio. 
  • The ability of the transmitter to deliver a clear signal depends partly on the receiver sensitivity. Very small receivers will not have very sensitive built-in antennas and will not pick-up as well as a larger receiver.






Accessories




This cable connects to the two RCA audio OUT jacks on TV sets, VCR, DVD, tape decks and other line level audio outputs. The red and white connectors are called RCA connectors and the other end has a 1/8 in. stereo female jack. This female jack is where the FM transmitter would plug in, connecting your source device to the FM transmitter's audio input.

See Audio Video Connections



Audio cable connects to TV output jacks usually in the back of the TV.
RCA connectors on one end and 1/8 in. stereo mini jack on the other end.
This connects the TV sound to the input of the FM transmitter so it can be broadcast out.


Cable used to extend the distance from TV to FM transmitter. Can also be used as a headphone extension to extend the distance from the radio to the preferred listening position.
1/8 in. mini plug at one end and 1/8 in. mini jack at the other end.
Available at Radio Shack in 16 ft and 20 ft cable lengths.
Radio Shack part number is 42-2562.




Connect the headphones to the radio. This will silence the speakers. You may already have these headphones but if not, you can purchase them at any electronics store or online for as little as $8 or if you prefer, you can use earbuds.

Stereo headphones. Make sure they have a 1/8 in. stereo mini plug connection at the end of the cord. Older stereo headphones can be used also if you buy a 1/4 in. to 1/8 in. adapter.


Headphone connection.



Earbuds with 1/8 in. mini plug. These are lighter weight than headphones.



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