# Looking for good quality fm transmitter



## tonyvdb (Sep 5, 2007)

Hi everyone, I am looking for good quality fm transmitter for my van. I want to use my Sansa Fuze mp3 player and Ive given up on getting the aux input adapter working thats supposed to work on my factory stereo on my 2005 Chev Uplander.
I currently am using a Philips FM transmitter but find it noisy and wonder if there is a better option?

There is also the option of one that connects directly to the antenna input of the head unit, any thoughts on that and whats good?


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## mechman (Feb 8, 2007)

I'd love to be able to help you Tony but I've never found one. I've tried several units with my iPhone and they all were tolerable at best. I ended up hooking up the aux in on my factory stereo. 

Sorry.


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## tonyvdb (Sep 5, 2007)

Thats what I am finding so far as well but sadly for me I have found that the "Aux in" on my head unit does not seem to work and I have tried two different units.
Thanks


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## AndyInOC (Dec 15, 2010)

Sometimes you have to get into the radios settings menu and turn the aux in on. Not always the case but certainly something to check.


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## xslatex (Sep 29, 2011)

In the meantime I'd check around for anything that may be interfering with the signal transmitted by your receiver. Maybe your phone or some 12V accessories that you could move around to lessen the signal interruption.


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## bawward (Feb 2, 2012)

There shouldn't be any signal interuption happening with the Aux-In, it could possibly be just a simple male/female connection that loosened from removing dash panels, etc. Also, the line could have been pinched from any number of movements/mechanics, etc. 

If it's with your Ipod, consider going into Itunes, right-clicking on a song (or ctrl+a to select all songs) and adjust the volume for all songs to 100% increased. Also, you may have your max-volume safety setting on your ipod set to very low, consider checking that in your ipod's system settings menu. 

You ever fix the problem?


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## tonyvdb (Sep 5, 2007)

Nop, never got it working so Ive just been using the Philips FM transmitter that i have. I just think there must be better transmitters out there that dont cost a fortune.


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## bawward (Feb 2, 2012)

There are those that are actually hard-wired into the back of the head-unit, although these are less-desired compared to an AUX-In or even CDs/direct Ipod connections. I've never done a wired fm-transmitter (they make them) but have had multiple friends do them, didn't seem to be bad at all really, and it saves on batteries and a cable mess on the dash between cig-lighter, ipod, etc.


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## tonyvdb (Sep 5, 2007)

Well, after two years of looking I have tried 3 FM units and one was noisy (lots of hiss) and is the one I am using now, one had to low an output level and the third picks up lots of interference from alternator noise.
There is no clear winner  
Anybody have any success?


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## willis7469 (Jan 31, 2014)

I have tried a belkin, and a Motorola blue tooth. Those two suffer from low output too. The belkin is manually tuneable, but sounds terrible with the phone gain turned up. The Motorola is auto tune only, and basically sux all the way around. 
Otoh, the very best one I've used was 8 bucks on amazon. It even came with a remote! It connected to the 30 pin and sounded great. No gain adjustments. (Not possible either). Then I got an iPhone 5, and needed a lightning adapter. The one I got would only pass analog. I was steamed, and gave it to my buddy. Haven't seen a good one since. (That wasn't 100 bucks anyway)


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## tonyvdb (Sep 5, 2007)

Im using a Sony right now and although the quality is good I think because it passes full range it also transmits alot of hiss. Its bearable but if the track has a low volume and I turn up the volume on my head unit the hiss is annoying.
You just cant seem to win.


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## gazoink (Apr 17, 2013)

Problems with FM transmitters for the car:

Finding an open frequency. Big problem in large cities, and what's open in one location might have a station on it in another. Plan to re-tune often.

Audio performance. Real radio stations use thousands of dollars worth of audio processing to squeeze the maximum modulation onto their transmitters. There's simply no way in the world you can even come close in a $100 or less transmitter, so the signal on the radio will be either very low, or loud and distorted. There's pretty much no middle ground. Radios don't have any modulation headroom at all, so even 2dB over 100% will be distorted. Unless you have a really strong signal on a really vacant frequency, the noise floor will be only about 40-50dB down. Subtract 6dB or so from the theoretical max and you have 34-46dB s/n. 

Separation, using a very expensive broadcast transmitter, can make it to 50dB, but on the cheapies don't expect more than 30dB. 

Basically, all the little FM TX's are hobbled by low cost and a crowded FM band. 

Spend the time or cost to get an expert to get the aux in connection working, you'll be glad you did. It has none of the problems above.


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## tonyvdb (Sep 5, 2007)

I wonder if this would work?


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## gazoink (Apr 17, 2013)

tonyvdb said:


> I wonder if this would work?


Interesting thing about that device, they make a very strong point about them being FCC Part 15 compliant, yet with that output power and antenna used without the attenuator, it doesn't meet Part 15 requirements. To comply, it has to radiate a field strength of less than 250 µV/m at 3 meters. The high power setting of .5 watt and the included antenna would exceed that, unless used with an attenuator, at which time there's no point. You can use any transmitter power or antenna combination you want, but to comply it still has to end up below 250 µV/m at 3 meters.

Part 15 compliance is now done with "self verification", which is probably how they got that thing registered...if the even did, the reg number doesn't come up in an FCC database search.

Assuming nobody cares if it's legal or not, it may have an advantage of higher signal strength, but that's only part of the battle. You still need to find a vacant frequency, ideally with at least the first adjacent channels on either side also vacant or low, or there will still be interference. But the big problem is audio processing: there is none. For unprocessed audio to be received without distortion it's average level must be between 8 and 10dB lower than what's found in FM broadcast stations. You give up 10dB of s/n ratio, and have to turn your volume up to compensate. If you modulate harder, peaks will distort. 

Audio processing for FM is not a simple or inexpensive proposition, and it's why none of these things can ever sound very good, especially compared to a wired aux input which has literally none of the quality issues. 

For the cost of one of those FM transmitters a professional should be able to diagnose and correct the line input problem.


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## tonyvdb (Sep 5, 2007)

Im up in Canada so the FCC rules dont apply to me anyhow. Im sure the CRTC has something but I would be using it on the low setting anyhow and in my home city there is a few dead spots in our FM band that are still clear enough to use.

I priced out getting the "aux input converter" for my head unit and its not cost effective at over $500. The head unit is integrated with a number of other things so I cant just swap it out with an after market unit.


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