FM Transmitter w/ Optional Charging USB Port
    Product # 10403
    FM Transmitter w/ Optional Charging USB Port
    Product # 10403
    In Stock This item should ship today (1/17/2017) if ordered within 39 minutes

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    FM Transmitter w/ Optional Charging USB Port

    So you love listening to your own music, but don't have an auxiliary port or tape deck in your car? What you need is this FM Transmitter with optional charging from Monoprice!

    This FM transmitter can transmit the selected FM frequency to your car's radio in order to play music from your smartphone or MP3 player. Simply select an open radio frequency on the FM transmitter, and tune your radio to the same frequency. Any music played through the transmitter will play through your car's sound system.

    The transmitter can be tuned to any FM frequency between 88.1 ~ 107.9 MHz at 0.1 MHz intervals. It has a frequency response of 20Hz ~ 16KHz and an effective range of about 5 meters.

    The FM transmitter's 3.5mm plug can be used to connect to most smartphones and MP3 players' headphone jack. It uses your car's cigarette lighter/auxiliary power socket for power, so you don't have to worry about the battery dying during your favorite song.

    The transmitter also includes a USB port that can be used to charge your devices at any time.


    • Wireless audio transmission over the entire FM frequency range
    • Works with almost any smartphone or mp3 player
    • Folding 3.5mm TRRS plug
    • Built-in microphone lets it function as a hands-free communications device
    • Rechargeable lithium battery
    • Includes car charging cable adapter with an additional USB charging port
    Model 10403
    Transmitter Frequency 88.1 ~ 107.9 MHz
    Frequency Tuning Interval 0.1 MHz
    Stability 10 ppm (+14 ~ +131°F)
    Clutter & Harmonic Distortion < -60dB
    Effective Range about 15 feet
    Frequency Response 20 Hz ~ 16 KHz
    Stereo Separation 40dB
    Audio Distortion < 0.1% (F=75KHz, f=1Khz)
    Signal/Noise Ratio > 45dB (1KHz 100%)
    Dimensions 2.3" x 1.2" x 0.5"
    Weight 0.6 oz.
    3.7 / 5.0
    40 Reviews
    5 Stars
    4 Stars
    3 Stars
    2 Stars
    1 Star
    Useful to dangerous in a matter of seconds.
    This thing works nicely when it works, but seemingly out of nowhere the audio quality to degrade, or it will cut out completely. It will also, for no apparent reason, activate Siri on the iPhone I'm connecting it to - sometimes I can do an entire drive with neither problem occurring, other drives, it's just a barrage of problems until I turn it off. People use these in their cars primarily, and I'm one of those people - I've for the most part given up on using the device, since when I do, it's downright dangerous. I've nearly caused accidents a number of times because suddenly the transmitter's signal cuts out and I'm being blasted with static, and I'm frantically reaching to turn it off or readjust, or I have to grapple with my phone to get the audio playing again. I understand that it's my responsibility to refrain from activities that distract me while driving, so with that in mind the transmitter is useless. And if you are considering buying this for a teenager, DON'T, I can't imagine how dangerous it would be in the hands of a less experienced driver.

    PROS: Wasn't hard to use, and I keep mine plugged into the included power adapter so I don't need to rely on the battery. Found a dead zone not used by local stations, and voila, I've got audio over FM.

    CONS: Very intermittent quality/functionality. Not worth the distraction while driving. Works solidly when you're stationary and have spent some time finding clear FM space, but after you start moving... it'll start acting up and you can either continually pull over to keep fiddling with it, or give up and turn it off.
    June 22, 2015
    This is one slick little product. Had it for couple of months and use it a LOT. My truck CD player quit on me and this is greatly prolonging me dropping serious money to replace stereo system. Even use it at home to stream my favorite college radio stations to my stereo system. It's antenna is in the attic and no problem with reception if I'm in den or outside using second zone on patio.

    PROS: 1) When plugged in top of my iphone, it looks like an extension because it is same width and thickness so in effect, making phone 1 3/16" taller.

    2) It holds charge pretty good.

    3) A standard usb cable charges it.

    4) And you can use it while charging too.

    CONS: NONE at all for this product! I hesitate to type it but here goes. The only thing to watch out for, and this would be true with transmitter by anybody, when traveling, you may have to change the radio frequency every 50 miles or so due to radio signal interference.
    October 18, 2013
    Great price and performs well
    I bought this for my son's car, and he says it works great. The antenna on his car is in the rear, so occasionally there is some interference due to the distance between it and the transmitter. But overall this unit performs as well as the ones in the local stores that cost at least 3-4 times as much. Very happy with this purchase, and would recommend.

    PROS: Low price
    Good performance
    Compact size
    Charging port for phone

    CONS: Some occasional interference
    February 26, 2014
    Good transmitter
    I really like this transmitter, but if you're an owner of an iPhone 5 or 5s this is going to annoy you a little. The positioning of the audio jack and this device are not really meant to be together. It ends up looking like a dongle and it's upside down. So if you're ok with that - this is the device for you.

    PROS: Small, easy to use, good quality

    CONS: not for all smartphone models
    March 5, 2014
    Great Product
    Easiest to use of any product of this type I have purchased (I've tried 5 different brands mostly to my dissatisfaction). Very effective. It seems stronger than the others and so much less expensive.

    PROS: Easiest to use

    Very effective. Seems stronger than the others.

    Much less expensive.
    November 19, 2014
    this thing sucks. it really needs the phone to be in some sort of mount to work. it easily falls off my gs3. not a good setup. if it had a cord like the sport head phones it may work better. definitely set it up before you start driving.

    PROS: works sometimes

    CONS: falls off easily
    April 11, 2014
    Response from Monoprice

    Thank you for your review. And I am truly sorry to hear of your experience you have had with this product. For now, if you prefer, I can assist you in setting you up for a replacement on the item if you haven't done so already. We do have a lifetime warranty on cables as well as a 1 year warranty for everything else. It will be of no additional cost to obtain a replacement, so please let me know if you want to continue. I would just require your order# to set it up. Thank you!

    John Lingo
    Tech Support
    November 18, 2016
    Monoprice Administrator M
    Works Exactly as Described
    This great little device transforms a basic FM car (or indoor) stereo into your own personal jukebox using just about any portable music player with 3.5 mm output. The addition of a USB port on the charger permits the music player (or smartphone) to be charged while playing. I've had it for about 2 weeks now and it has not failed me.

    PROS: Strong signal to FM stereo

    Additional USB charging port

    Access to full range of FM channels

    CONS: None so far...
    December 3, 2013
    Nice, compact FM transmitter
    This little FM transmitter is great. The plug flips out and it just sits on top of the 3.5mm headphone port on whichever device you're using. I can see this being a problem if you have a thick case around your device, but seriously, buy an extension cord or adapter if that's an issue. I'm that is the problem with most people saying that it doesn't stay in, because I have no problem with mine when it's flush with the port.

    The audio quality is definitely acceptable for an FM transmitter. The signal strength is fine especially considering I live in a large city with lots of radio stations and my car is missing its FM antenna.

    Every other FM transmitter I've owned has had one issue or another. Either the signal isn't strong enough, the battery life is bad, turns off when the volume of the music gets too low, etc. But this one doesn't seem to have any of those problems, and it's cheaper than most of the other ones I've had. Definitely a good purchase.

    PROS: Very compact

    Good battery life

    Standard MicroUSB charging port

    Strong enough signal

    Good audio quality

    Does not turn off randomly when volume gets low like others I've owned

    CONS: So small that I lost it once, but I found it again! Yay!
    May 23, 2015
    There has got to be a better way...
    I tried to use this device in my car while driving in a location. (LA area) I was never able to find an FM channel quiet enough to make use of this device. There was always interference. I found the device would shut itself off in seconds if the audio stream disappeared. Auto shutoff in minutes would have been better.

    PROS: Small and light enough to use the 3.5mm jack as a mount.
    Reasonable battery life.

    CONS: FM signal relatively weak.
    Shuts itself off within seconds if the audio stream ends.
    February 26, 2014
    FM Transmitter w/ Optional Charging USB Port (10403)
    Never got to try functionality because the phone case is a show stopper.

    CONS: 3.5mm jack does not fit in my phone because of the phone case.

    January 5, 2015
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    how do i insert the charger usb port to my cigarette lighter socket when the side spring contacts does not retrack? Could not be inserted
    A shopper on Dec 20, 2016
    BEST ANSWER: if the spring contacts aren't retracting, then something is wrong with the unit- contact monoprice for replacement. The springs on mine are stiff but with a little push it slides in to the cigarette lighter socket just fine. Also check your cigarette socket to make sure nothing is broken off or stuck inside
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