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Picture of The Tunecast Auto Universal
I got tired of always having fuzzy reception from my car FM adapter, which is the Belkin Tunecast Auto Universal. There's a few tutorials around, but none for this particular model.

There are a couple of really easy things you can do to boost the transmission power. It seems to make a pretty significant difference to the reception.

The thing is a little tricky to tear down, so I'll post some photos of that process.

Here we go...

*** Disclaimer: Boosting the output power may cause your transmitter to exceed FCC regulations on unlicensed FM transmitters. Neither Instructables nor myself assume any responsibility for your actions; this instructable is provided for learning purposes. You should accurately test the output power of your transmitter to make sure it is within regulation or you may incur a fine or other penalty.

Step 1: Remove the buttons

Picture of Remove the buttons
The buttons are pretty easy to take off. You can just pry off the "U" shaped preset buttons, which click back into place easily.

The up/down tune buttons are secured to the face with adhesive. You just have to pry up the buttons and deal with the fact that you might have to reapply adhesive. These need to be removed since there's a screw underneath.

It works !!!
Thanks for your great help...
rwebber814 years ago

I received a Tunecast Auto with the 30 pin connector for Apple Products. Is there any way these can be fitted with a 1/8" male connector like the Tunecast IIs?

Yes and you can even charge your phone if you wish! Cut the cord at the 30 pin connector.

The Red(+) and Yellow(-) wire wraped in blue foil is for charging.

The "big" white wire contain the left, right and ground for audio signal (Green, Yellow and Bare).

You need to connect the small brown wire to the charge port ground (yellow wire)

The small Blue and the White wires are not used as these were for data transmission with the tunecast app on the Iphone/Ipod

Hope that help!

P.S.: I included some pictures of my WIP setup.


For the Audio, Left is Yellow, Right is Green, and ground is bare.

jimtran935 years ago
Just did the inductor-bypass hack, took me 5 minutes, and what a difference it made!

Looking to do some kind of antenna amplification using an op-amp (the LM 741CN to be exact) I have handy thanks to my introduction to electronic circuits course. Any know if it would be as simple as wiring up the antenna connection to the non-inverting input (along with setting up the V+, V-, and feedback resistors, etc)?
twocvbloke7 years ago
Looks like it's a more basic version of the Tunecast 3 like what I have (somewhere, I gave up with that thing, kept cutting out during quiet parts of my music!!), as seen in my only Instructable... :)

I wasn't as scientific with my mod though, I just slapped a long dangly wire onto the antenna points and soldered the opposite ends together, works great and has a god range... :)
solis365 (author)  twocvbloke7 years ago
yeah, it really wasn't a huge improvement, but it was noticeable. The thing is still very dependent on whether you have a lot of radio stations in your area too.

I put a long dangly wire on it but eventually it broke off and I had to solder a new one on... kind of a pain.

lucky me, now I have bluetooth enabled radio so I don't have to fart around with this thing any more ;)
justlaxn5298 years ago
hi! does it matter what type of wire I use to bypass the inductor? thanks
solis365 (author)  justlaxn5298 years ago
not really, it just has to be small enough that it will solder to the pads. I just used a very small clippping of 22AWG solid-core wire (the kind used for breadboarding)

the other thing to make sure of is, if you are using stranded wire, that none of the strands are loose and shorting anything on the board out.