Violating the law: making a cheap FM transmitter useful by adding an antenna

The FCC made some changes and now car mp3 player FM transmitters must not transmit enough to actually be useful.  This makes it difficult to even listen to your tunes or pod-casts in a rental car or company car.  So I set out to modify an el-cheapo (tm) FM transmitter/ Mp3 player that I found at a discount store called "Big Lots". (You can buy them here as well.... Google Shopping LinkIt is a no-name china made device that is really cheezy.  It has a small IR remote that comes with it as well as a 3" long stereo plug to go to your phone.   Following my instructions here is a VIOLATION OF THE FCC TITLE 47 PART 15.... for more info on this.  

So all of this information is for entertainment purposes only.

The funny part is, this china manufacturer actually make this really easy for you.  IF you look closely at the board you will see where the ribbon cable goes to the USB daughter-board, a designation "ANT"  this is most of the time  what stands for Antenna.  They practically handed us where to solder our wire.    Let's look inside....

If you look carefully, you can read the word ANT by the ribbon cable,  but this is offset, It actually means the last wire on that ribbon cable that is not red.  This is confirmed if you look at the other end of the cable.  Problem is, I cant photograph that one.  All we need to do is solder a nice long wire at that point and pass it out of the case.  I used a 36" long piece of thin stranded wire.

Solder it up,  I melted a notch in the edge of the case with my soldering iron for the wire to pass through and snapped it all back together.   The first image at the top of this post is actually the finished hack.  All ready to go.  Now I can run that wire up to the face of the radio and get nice clear FM modulated podcasts while I drive in the company car.

Problem is the mp3 player in this unit kind of sucks in that it loses it's place and starts over when power is lost, and there is not Fast Foreward or Rewind.....  But it will accept a 8 gig usb drive just fine.   I have not tried any SDHC cards.

Nothing like a quick hardware hack in the morning to get your creative process going!


Post a Comment