FM transmitter

Several things are at play in using the FM Xmtr function. Probably the most important is the location of the FM antenna for your car. Signal strength decreases rapidly with distance, and if there are barriers - such as a metal roof between the source and the receiving antenna, there are even higher losses.

I have an 885T, and I won't even bother with the FM as my car radio antenna is mounted on the back center of the roof and my GPS sits on the dash at the front. I'll probably spring for a cassette adapter (I don't have an aux or line in input either) to get the unit to play through the car stereo.

I live in Miami and it is useless. However, I recently drove from Houston TX to Canada (a few times actually) and the FM transmitter worked great as soon as I cleared the radio stations in the Dallas/Ft. Worth area. The more empty the channels, the better your reception will be.

If you live in a major city with a lot of radio stations, forget about it.

And as A_User stated, it is also affected by your vehicle antenna location related to your GPS location.

As Greg2561 said, if you are in a large city, the FM Transmitter is pretty much useless.

However, I know local Best Buys up here in Canada can install some sort of switch which will turn off receiving external FM signals and only accept transmisstions from your Nuvi (or Satellite Radio, etc).

I have not tried such a gadget and I am not sure about the details on how it works, but if you wanted to listen to your mp3's, an audio book, or another fm transmitter device like satellite radio in a large city, you may wish to enquire about it.

I found the Traffic service to be unreliable due to inaccuracy. In DC, it is far better to listen to WTOP (FM 103.5) every 8 minutes on the 8's each hour.

The traffic reports are every 10 minutes or else they wouldn't fall "on the 8's".

If you do a search on this site, you'll find a lengthly conversation about FM transmitters in these devices, and several potential fixes for the weak transmitters.

Cheers......... Joel

Garmin should stop advertising the FM transmitter as a benefit to there units. In fact they should do away with it altogether and spend the money to give us a feature that works and is useful.

While I agree with you, the reality is that the marketing departments of these companies do not care how well a feature works. They don't even want to know (picture the 3 monkeys - hear no, speak no, see no). They just want to develop a long list of features for their glossy brochures.

I've found the best solution is to install an Aux In feature in your car. That way, you can play your mp3 files thru your car stereo system with great quality sound & routing directions will automatically interupt your music, as it was intended to do.

I've even set that up on my Goldwing thru the cassette player it it works fine too, although not as well as the Aux In in the car.

Fred

The FM transmitter as everyone points out is a waste. The internal voice is loud enough for direction and since the traffic info in most cities seems to be useless, the FM could be removed and we wouldn't miss it.

OK, I understand that there are work arounds. For a myriad of reasons, I'd really like this function to work... AS ADVERTISED. I paid a measurable premium for an fm transmitter and it has been unusable anywhere. Based on the responses I've seen here, it looks like the answer to the question of whether or not Garmin has done anything to rectify the problem is (drumroll) NO

The FM transmitter in Europe is much stronger than in the USA on the same models. Why I don`t know, but has to do with FCC control.

Garmin CAN'T do anything to rectify the problem, i.e. increase transmitter power, because the FCC limits the maximum transmit power of these devices.

I've read this in numerous places on the web about this topic and it simply isn't true. The output that the FCC cares about is a dB measurement 3 ft from the antenna. The actual power output of the unit, whether it is .05 watts or 15 watts, is immaterial. They only care about what goes out over the air. Garmin has CHOSEN to limit the output so that I don't get in trouble with the FCC for exceeding the transmission limit without a license. I don't have the skills to measure it, but I'd bet that the GPS output can be significantly increased without coming close to the FCC dB limit. There is a selectable power output setting within the unit, I should be able to choose the one that works best for me within FCC limits. If theres a problem it's on me, not Garmin.

My guess is that your car's FM antenna is in the rear of the car, and the cable from the antenna to your receiver is well shielded. Because of this the Garmin's signal, which weakens by 1 over the square of the distance from the GPS, is too weak for your car's FM receiver to pick up. In other words, it may not be Garmin's fault.

Since there's little reason for Garmin to make its output power be less than the FCC limit, they are cannot add a switch to increase power. Try attaching a short wire at the back of your car receiver's antenna input to act as a antenna/pickup closer to the Garmin. Since the signal is stronger there, it might work.

Not so. The FM transmitter function in the unit is licensed by rule and type accepted according to their EIRP which is measured as field strength. If Garmin allowed the radiated power to exceed the levels accepted by the FCC, Garmin can and will be fined for all units sold that allowed the power limits to be exceeded. Yes, it's probably true during manufacture the level is set lower than the maximum allowed through testing, but that's to protect them in case there is a failure.

Maybe I'm lucky, but the FM trans works great in both my cars. The antenna must be in the front driver's side in both of them. I have a 780 (760). When driving long trips occasionally I'll have to re-tune things to empty station.

I love the feature, lets me play tunes and listen to the GPS.

The FM signal is loud and clear from my 750. I have it mounted just above the radio in a Toyota Sienna.

The only time this feature works is when you are intercity and there are few FM stations transmitting. I have an aux in on one of my cars and it is far better and much more reliable. Even if you find an FM station that works while intercity you often have to start fiddling with the settings as you travel. A dangerous maneuver at best.

I have one of those on my Sirius radio - I think they call it an FM Direct Connect unit. It plugs into the back of the receiver unit, and connects to a small box. You pull the car radio antenna out of the back of the radio (in dash) and plug it into the box. The box has another antenna lead that goes into your car radio. When it senses an output from the Sirius unit, it turns off the connection from your car antenna, sending the Sirius signal through. When the Sirius radio is off, it switches back to the car antenna input, allowing you to receive over-the-air signals.

I'm not sure how well it would work with a Nuvi - I don't know if the plug port would even be the same on a Nuvi and a Sirius/XM receiver (it's different than an Aux Input plug). And if it did connect, I don't know if there is always an output signal from the GPS - if so, you wouldn't receive terrestrial radio signals, that antenna would be effectively disconnected. In that case, you would probably need to have a set of mp3s loaded up to listen to. I guess it's possible that if the GPS only sends a signal when it has something to say, it would cut out the radio during those times, and let you hear the radio the rest of the time.

It was fairly easy to install - only took me about 10 minutes, but I'm handy working on the car.

do a web search for an "FM Modulator" that will give you and "AUX plug" AND will switch to the GPS (shutting down the antenna) when turned on. They're usually power directly by ignition power, however that is really your option.
They were big when CD changers for cars first came out and dealers wanted to put and AUX input on OEM Radio.
They should run you < $25 US for a really good one.

I have a garmin 670 and the transmitter is not very strong and some times loses the station. I did test mine to see how far from the car you can have reception , and it is not that far.
As for some one suggested I think I am going to buy a separate fm transmitter for better enjoyment of the gps directions and the music I have on a 8gb card. I hope that helps.

Here is an interesting thread going on here ... a user has wrapped a wire around his GPS and significantly improved his FM signal.

http://www.poi-factory.com/node/8703