FM Transmitter Hack?

Calling all electronic geeks. Is there anyway to hack an FM transmitter for an iPod or other mp3 device to boost the signal strength? I've got a Maxell FM Transmitter that I keep in my car for my iPod, but reception is pretty crappy. Here in the LA area there are so many stations that there are not many frequencies to choose from that work.

When I play classical music, which is notorious for being mixed really low, much less than your average rock album, a tiny bit of static will be enough that my car's stereo drops the signal and broadcasts static.

Is there any way to hack that thing to boost the broadcast signal to make it stronger and clearer?

The easiest way to boost the signal on a transmitter is to replace the antenna with something tuned to the wavelength (or a multiple). Here's a calculator to find that for a given frequency:

Frequency Wavelength Calculator

You could buy one of these kits. You may need an inverter as well.

Paul

LayMeister said:

You could buy one of these kits. You may need an inverter as well.

Paul

Click to expand...

I'm thinking something cheap and relatively simple. Not worth it for the $25 spent on the Maxell piece of junk!

ChshreCat said:

The easiest way to boost the signal on a transmitter is to replace the antenna with something tuned to the wavelength (or a multiple). Here's a calculator to find that for a given frequency:

Frequency Wavelength Calculator

Click to expand...

So how would I go about doing this? Off the shelf parts at radio shack?

You can get a very cheap stereo for like $50 that has an auxiliary input. If you dig listening to your ipod in the car, I would go for it. I spent like $250 on an ipod compatible unit that allows me to browse artists, playlists, etc. It rules, one of the best $250 I ever spent.

I'd be interested in this too. In the end, I'm going to get a new stereo. I'd like to see if there is a quick fix in the mean time. I have taken to listening to beer podcasts in the car because I can't get great quality in my music. I don't care if Jamil or Graham's voices are slightly fuzzy.

There is a certain fm transmitter...the C Crane that has a "hidden" pot (potentiometer) inside that lets you boost the signal.

Digital FM Transmitter

The info for the hack is posted openly on Amazon...

Amazon.com: C. Crane FMT Digital FM Transmitter with AC Adapter: Electronics

1) Open up the box,
by removing 3 screws (one screw is in battery compartment and the other 2 are under those circular rubber feet which are adhesive and once removed can be refitted afterwards)

2) Locate the variable resistor marked VR2 on the circuit board. (For those non-technical this is like a volume control that is operated by inserting a tiny screwdriver and turning fully clockwise). Turn VR2 to the fully clockwise position.

Viola! The power output will increase by about five fold

That's the one that comes to mind!

I have no first hand experience with the unit...but am probably going to pick one up.

I have one of these C Crane Transmitters, and yes you can turn the internal variable resistor to increase power. Note that it is not legal to do so, or C Crane would just ship it that way (they can not due to FCC power regulations). Unless you do something to cause interference (like jamming your neighbor's favorite station), then you are unlikely to cause problems (except maybe while mobile in your car... you can override some stations in the car next to you).

Once you turn the resistor up, you get PLENTY of range and power. In fact you can "jam" local stations from within a few feet (which is not wise to do). Use one of the many websites that ask for your zip code and suggest an UNUSED frequency.

With this adjustment, I can stream audio from my laptop to EVERY radio in the house. It's really nice, since the audio is perfectly in sync (which would not be the case if I tried to rig up actual streaming audio over the LAN)

I HATE those damn things! Hardwire it into your damn car.

I'm tired of listening to Freaking Howard Stern and sh** music while I'm driving and trying to follow a story on NPR. Dammit, people! Tune those f***ing things to a dead channel and get it off the M*****F****** detault station!!!

Um... yeah, finding an unused frequency was exactly what I said.

You seem convinced that personal transmitters are the cause, but know that MOST FM transmitters are deliberately underpowered due to FCC regulations, and are barely capable of reaching 3 feet to the owner's car radio.

If your tuner can be knocked off that easily, you're either at the limits of the station or your tuner is junk (and I do not need to know what the radio costs... I've seen expensive radios fail at tuning, and ones half the cost excel at it).

FWIW, my "local" NPR is right on the edge of what my 17 year old (and once expensive) Alpine will tune.. if clouds roll in, it rickrolls to country or hiphop. Driving the same route, my wife's Nissan Versa tunes it just fine no matter the weather.

holy Zombie thread, Batman!





if the car is too old for an AUX input, and not too old for one of these- they plug into the back of the CD player
and you can then use the two RCAs to create an Aux In -

hardwired, baby!

You can get an adapter, like the one above, that uses a WIRED connection to transmit via FM to you radio. It disconnects your antenna when it's powered up, so you won't get interference from local stations. I think Walmart sells them online. SCION or some such company makes them. I think they go for about $25.