Picture of Belkin Tunecast II FM Transmitter Mod
Belkin is a popular manufacturer of cheap and cheerful computer accessories, having singlehandedly made the USB hub sexy! One of their more popular product hitching the iPod popularity ride, is the Tunecast II FM Transmitter.

It is only earlier this year (2007) that FM transmitters like these became legal in the UK, ignoring the fact that savvy netizens have already brought theirs from eBay.

This modification improves the transmission range and remove the 'feature' of auto-power down when no audio signal is present. It certainly sets you up as resident pirate radio DJ of your block and allows you to jam the loud radio listener on a bus or train!

Please note that this is a rehash of something that was done before 'instructable' came along. No more the delay now for the good stuff!

Product link:

Step 1: How to gut the TuneCast

Picture of How to gut the TuneCast
Those ever efficient Taiwanese manufacturer manage to secure this piece of gadget with just a single screw, if you're handy with a screwdriver, that's the job done!

The first image shows the location of the screw (ignore the switch for the moment, that comes later), the second one shows where to a gentle pry will open it, note the plastic latch.
natong6 months ago

Why we can't use the old blue cable? have to use the new one.

Daerken1 year ago

I know it's a bit late for asking something about your tutorial. Thing is they have released a new version of belkin tunecast transmitter II and it seems that they have removed the BH1415F. I am trying to find which pin is source of the antenna but I have no good results. If someone could help with the photos I have uploaded it would be awesome !




Hello Daerken,

Did you find any solution


As I said I just replace the wire that were used as an atenna by a real one (of about 70 cm) which gave me a signal significantly better. However I did not find the attenuation component. Today you can find very cheap and powerful fm transmitter on Internet from different countries where they have no law on fm transmitter power. Unless you really want to touch to the electronic which is not easy, you will gain time and have a way better fm transmitter by bying a cheap new one.



OK. I tried that by just contacting the antenna by a wire ( from an unused ethernet cable), but I can not hear any difference in signal quality.

HefLuc Daerken1 year ago

Daerken, I'm having the same problem as you. Have you found a solution? Please let me know!



Daerken HefLuc1 year ago
Hi HefLuc,

I soldered an antenna to the output (blue wire on my picture) and it works way better now but only because the default "antenna" is very bad. However I did not find the resistor that reduces the signal...

If someone does, please share it !



Did you find the resistor that reduces the signal in the revision 1.02 of Belkin Tunecast 2?

Mine transmitter looks exactly the same like in the pictures attached by Daerken.

Thank you for help:)

okakar1 year ago


Darkcobra04 years ago
The Corrugator, this is a great Instructible!

I used a different method to boost the output power, which will work not only for the Belkin Tunecast, but for ANY transmitter which uses a BH1415F, or even any other Rohm FM transmitter chip. Instead of trying to figure out what components were involved in the filter/attenuation network, I used a soldering iron and a toothpick to lift and disconnect BH1415F pin #11 (RF output) from the board. Then I soldered a quarter-wave wire antenna directly to the pin, which gives direct access to the maximum possible output power. Make sure the wire is secured so an accidental tug won't rip the pin off the IC; I used a generous application of super glue to attach the wire to the board near the connection. If a transmitter uses a different Rohm FM transmitter chip than the BH1415F, look up the datasheet to find out which pin is RF output.

The real gold in this Instructable is the auto power-off disable. I've been using this transmitter to listen to music from my computer anywhere in the house, and have been looking for a good way to disable the auto power-off. Up until now, I've been doing it by running a separate copy of Winamp that plays a subsonic or ultrasonic burst for two seconds, every 30 seconds in a loop. It worked, but on some radios you could hear a slight distortion when the burst played. This may still be a useful option for people who aren't comfortable soldering, or who have a different transmitter.

I just performed your auto power-off disable mod, and it works great! Though I did make one change. The pad you're getting power from appears to be active only once the transmitter is powered up, which still requires an initial audio input. So instead, I connected the transistor pin through a 1M resistor directly to the positive pin of the DC power jack. If you're looking at the board from the LCD side, with the power connector on the bottom, it's the second pin from the left between the large SMD capacitor and the LCD (verify it with a voltmeter if you're unsure you have the right one). The transmitter now turns on immediately when power is applied, and stays on indefinitely; regardless of audio input.

Finally, one more tip. Loop the power and audio input cables a few times through a ferrite toroid filters out hum and hiss. You can use one toroid, but it's easier to use two, one for each wire. The more loops, the tighter the windings, and the closer to the transmitter, the better it works. A clamp-on style ferrite should work almost as well, though I haven't tried. Obviously, don't loop your antenna through a ferrite, as this will attenuate the signal. If you haven't added your own separate wire antenna, skip the toroid for the audio cable, as it contains the antenna.

With these changes, I'm very happy with the performance of this transmitter; and its range and quality rival any consumer or kit transmitter I've tried for less than $100.

I was wondering, will the mod you did work at 300 feet? I am wanting to build a transmitter that will work at or over 300 feet and transmitt through the whole house.

I've tried this variant on two tunecast II's and the results are wonderful. Thanks both to you and the instructables parent.
Wow, thanks for the generous updates and mods! I am sure somebody will find it useful too.

A bit about the Rohm FM chip... Before these iPods, many FM transmitters came in kit form, and the Rohm chip was the first to be highly integrated and made it easy to build these. And I think you could get single chip (with earphone amps) FM radio tuner too.

It is a great little FM transmitter isn't it. In terms of fidelity, if you get it right, FM transmitter still kind of sound better than Bluetooth speakers. Heh, kind of please there's still a purpose for this old instructable. Cheers!

samander1 year ago
What's the range on this hacked transmitter? I am looking to start my own pirate radio station and I need to do it cheaply.
jamesmount2 years ago
Hello i am jamesmount
According to me if u want to increase the power for transmitting the signal.for this we decrease the frequency... because frequency is inversely proportional to wavelength, i hope if we are working in this principal your problem will be solve as soon as...
for more information visit http://www.broadcastdepot.com/
tvane12252 years ago
if you increase the voltage to the unit using lets say a 9 volt battery, will that increase the effective range of the transmission?
internicht3 years ago
Won't let me post pictures - trying again...
internicht3 years ago
Good and clear instructions - but my layout is a bit different, with what I think to be the inductor vertical instead of horizontal.

I tried a reception test just touching a contact attached to a wire to various components (starting from what I think was the chip-side of the inductor) but could not improve reception.

The only thing that did was the lower right pin of the chip on the rear (marked 1 on first pic below), so I soldered my wire to that. Now I get reception up to about 25m away through several brick walls (having got about 5m out of the box if I was lucky). My wire is about 1.5m long, and I didn't experiment for the optimum length, as it works (and this is to be used inside a house anyway).

As for the auto power-off mod, that went wrong too! I fluffed the solder a bit to the top-right contact point, and it seemed to disappear leaving no metal to contact. Doh! After a bit of experimentation, I found that the same lower right leg of the other component (marked 2 in pic below) when jumpered to the resistor right next to it (marked 1 in pic) put the Tunecast into an always-on state. I settled for that, as again this is to be used in the home, it only uses about 2w, and I am powering it from a transformer anyway so I don't have to mess about with batteries.

Thanks for the guide anyway!
lhj7340173 years ago
Alternate Antenna Method: instead of adding a separate wire for the antenna, install the 3.5mm headphone jack and solder one end of a small piece of wire (you can use the blue wire that used to be the antenna) to the inductor bypass point and the other end to the ground on the headphone jack. The ground wire on the line-out cable used to hook up your mp3 player, will now act as an antenna; the longer the cable the better the signal. This works best when the cable is spread out
Hey this is pretty cool! Does it broadcast as far as the WH FM Transmitter ? I heard it goes up to 150 feet.
pigmeat7 years ago
I have a Belkin copy, by a company called Sansai (see image) and it works great, but I'd like to modify it with guidance from your instructable post. My only problem so far is getting the damn thing open. Unlike the Belkin this thing has no screw and I had a hell of a time trying to pry it open (without success). Has anyone here managed to open one of these? If so, how did you go about it?
uhclem pigmeat3 years ago
To open:
Slip a metal putty knife or screwdriver blade between the darker (or may be metallic) oval trim and the plastic case and pry it off. There are three screws underneath. Remove them and you're in.

It looks to me like they put the FM signal on the ground, so your USB cable and your audio cable are acting like an antenna. Probably best to find the RF output pin and connect directly to that.
uhclem uhclem3 years ago
I just tried out my Sansi-type transmitter and the results are excellent. I attached a pair of clip leads end-to-end to the ground point and got a clear signal from one end of the house to another. I bet you could cover 1000 ft outdoors with a clear line of sight.
Don't need to open.. if you put usb power with a big cable (70+cm) you can do emit in 100 meter!
wilvan pigmeat4 years ago
Hi Pigmeat,

Is been a while since this trheat was open, anyways I have the same gadget and like 'mdphoenix'' mentioned is correct about opening it.

Now I have a question of my own, not sure if the gadget is the same circuitry is yours..
I need to find the tiny inductor and bypass it to attache antenna.

Thanks and Regards
wilvan wilvan4 years ago
Hi Corrugator, any idea about this item and its boost mod?

Thanks and Regards
Corrugator Supercilii (author)  wilvan4 years ago
Sorry wilvan, it is not possible to see what happening on the circuit without a bit of hands-on, really can't help you...
Corrugator Supercilii (author)  wilvan4 years ago
You have to reply to PIGMEAT not me my dear, PIGMEAT wouldn't get your message if you send those bacon to me.
richms pigmeat7 years ago
I don't know if you have got anywhere with this, but the one pictured is a hugetide c-007B - the black cover with the < O and > buttons will come off (held on with tape) and there's 3 screws under it. I am still playing with defeating the auto power off on mine, when I have some luck I will post an instructable here.
pigmeat richms7 years ago
Thanks for this. I have since got another model with a screw and have opened it up. Yet to do any mods as other projects are more urgent.
Out of curiosity, what DO the < o > buttons do on yours? I don't have them, but the spaces for them are under my bezel.
I know this is a year old but: I have a similar unit. Mine is made by iWave though. The gray bezel around the front comes off and the screws are under there. My board was different but I could still locate the attenuating inductor just above the antenna solder joint. Good luck.
michel234 years ago
Just did this mod, on another board.

The first experiment was to extend the antenna. I cut the blue antenna line at 2cm. Soldered a line of 80cm to it. Result: worse than the original tunecast2.

Second experiment: I removed the old antenna (just ripped it off) and soldered a new line to the board on another position, see picture below. Much better result than my first experiment, however, I cannot tell if it's better than the original tunecast2.
Please do not laugh at my soldering technique/result, I'm not very good at this i'm afraid :-)

Third experiment. Note that this step cannot be undone. Using a knife, I cut away that small white thing below my new antenna. It did not seem to make things better or worse. I forgot to make a picture of this, and currently I'm too lazy to reopen the device and take a picture

Tomorrow I'll drive 200+km and will let you know if it made things better or not.

Result: it seems to make no difference at all, compared to the original tunecast. Still a lot of noise during playback. I cannot recommend this at the moment
Initially, it did not seem to make much difference. However, the following made this work fine:
* I drilled a hole to lead the antenna out of the enclosure directly
* Make sure that the sigaret lighter in your car is tightened securely so it cannot move
* make sure that the antenna cable and the power cable are separated well.

These three all caused interference. Having found this out, it makes the Tunecast useable.
Capfl2k54 years ago
this worked wonders for my little el cheapo 6 dollar transmitter i picked up at a truck stop on a road trip. it wouldnt so much as cause static on an empty station unless it was tucked in the corner of the windsheild by the antenna. But my question is will this shorten battery life any?
Kurk2314 years ago
Good Instructable, good pictures and very good details too. The method I used for boosting the signal was as simple as bridging the Inductor (the slightly iridesent black box thingy to the far left of the LCD display) with a wire soldered to either lead, effectively bypassing it without removing it from the PCB. Worked great for me, I've tested it up to 20 feet without adding a new antennae to the FM tuner. I wouldn't be surprised if it's signal strength stays strong even farther than that. Obstructions kill the signal though, if testing with a home stereo's radio, you will find that clear line of sight is key outside of about 2.5-3 meters from the receiver so walls are an issue.
ferralll6 years ago
I did this on my wife's Tunecast, and now it works great. (or atleast part of it) Before, if you were around a city, you would need a lot of luck to find a good station. Now, I can beat out most of the non major (local) stations! Thatsk. What I did (if any one wants to know) I used a good soldering iron, and some VERY thin gold wire (did at work under a microscope) and just made a shunt around the Inductor that you ripped out (ripped up). It works great, and turned it from almost useless, to very effective. I am now trying to do it to my brother in-laws Belkin TuneFM. (this one is much more difficult to open, and the components are much smaller and closer space. If I get the chance, I will post pictures.
wjie20 ferralll5 years ago
Hi, was wondering if you have succeeded on the TuneFM? Because I'm also trying to mod mine. Would appreciate if you would guide me in to this.
ferralll wjie205 years ago
I have tried to do it with the TuneFM.
But it did not work.

I am going to try again once I get some time. I will post something here if I get it to work.  (there are inductors in different places, so I do not know that I did the right one)
wjie20 ferralll4 years ago
I see, any luck?

Actually, I found that soldering the antenna lead to the grey box-like object directly to the left of the old antenna lead gives better results.
Sorry if this might be a stupid question, but couldn't one soldier the blue wire to the new connection point and see results?
Joby16645 years ago
My Tunecast was different to the one in the example when I opened it. I couldn't find the inductor so I soldered the antenna to one of the legs of the transmitter chip which seemed to be producing the signal. Will this produce the same result or have I made a mistake?

I can't see the equivalent components to bypass the auto shut down either.

The tune cast is a piece of junk anyway. I bought this transmitter in the end, http://www.ccrane.com/radios/fm-transmitters/fm-transmitter.aspx. It's outstanding, plus it's incredibly easy to moify, see here:
They even shipped it to me in the UK with no problems. I would really recommend it 100%.
ewfw5 years ago
Good old instructables never die.  I have been searching the net for a transmitter.  The reviews on the tunecast are pretty weak, but so is the competition.  What would you say the effective range of this is after the modification?  I want to use this to broadcast a metronome wirelessly to my band. 
lordjohnnym5 years ago
the british electronic chain store.
finally someone who mentions stuff you can buy in the UK.
most instructables are american or written for americans.
i bought one of thes transmitters from Tesco, for 7 quid last week, and  it seems that the best quality is at the bottom on the fm band, and the best signal is at the top.
ive been also looking for some way of extending the arial, to give it extra range. i was going to increaser the output wattage, but i remembered that it might blow the diodes.
anyway, what i find funny, how mine is technika, and your is belkin, and they both look near enough the same, and have near enought the same layout.

good instrictable otherwise, keep it up. ;)
I performed the antenna mod on my friend's tunecast. We are able to broadcast about 45 feet each direction in the cnc machine shop we work in. We now operate a shop radio station off my ipod during the work day.
Does anyone know anything about this iWave FM Transmitter? I bought it at ross and it had a Car usb adaptor thing that came with it. Here are some pics. I will post pics of the inside later. It has a clock, thermometer ( I can see a Fahrenheit thing on the lcd but it displays Celsius. The product didn't have an instruction manual in it so if anyone knows how to change it to Fahrenheit please tell me). It even has a led flashlight :D.
gprix15 years ago
What did you use for the plastic piece on top of the tripod? How is it holding the transmitter?
mixadj gprix15 years ago
 I was wondering the same thing...... 
Corrugator Supercilii (author)  mixadj5 years ago
That mr dear, is mighty polymorph plastic, see my other instructable for more info on this.
Replacing the cable seems like a lot of unnecessary work; just use a 3.5mm stereo headphone extension cord.
Agreed. The antenna mod is great, but it's not much more money and a lot less work to just use a headphone extension cord for this part.
wquoyle thx01385 years ago
Trouble is the audio cable/plug is awful quality, I've had to solder on a new plug three times so far on my Tunecast due to the cable wearing and shorting out. Dumping the cable and installing a socket is the best mod you can do.
elantrix6 years ago
Can you also add a way to solder a DC plug into it. Other then that, it's a pretty nice mod.
(I apologize for the repeated posts, but I'm not getting any feedback.) I was able to complete the mod and it did dramatically improve the output of my Tunecast (great), but for some reason, I'm only getting the Left channel (no sound from my Right speaker) even thought the "stereo" light is lit on my receiver noting it detects a stereo signal. And yes, the speaker plays fine when switched to regular radio. I'm also getting enough "hiss" to be annoying (no matter what station I choose). Anyone have any ideas?
I am seriously confused here. You are connecting BOTH the blue antenna wire AND a separate external antenna to the transistor (?) in the middle of the photo (does it matter what end you solder the wire to? Both ends? And how is the inductor "bypassed"? Do you cut one of the leads or run a wire around it? (or both?) Please help.
Okay, I think I have it now. After blowing up the photos, it appears you soldered a bridge between where the inductor was connected to the left 'L6' contact (the two L6 contacts do not appear to have been bridged), where you also connected the external antenna (the internal antenna does not appear to have been reattached).

If I'm mistaken, someone please let me know. Thx.
This belkin fm transmitter haves 2 chips. One, Amtel Eprom and one Toshiba with programm and up down 88 - 108. See the youtube video how to convert this transmitter! http://www.youtube.com/watch?v=LsZw_youJAo
dj Kostas http://myitalodisco.blogspot.com
really good plans, simple and effective. took me about 10 minutes to do this and the audio quality is perfect over 5 meters, have yet to take the radio further away to asses the range but i am very impressed. transmitter broadcast is strangely directional from the telescopic rod and needs to be angled straight up, gonna be looking for a better shape for omni-directional transmission but its awesome just as you described.
10 minutes? Yeesh!

I'm having a little difficulty seeing *exactly* where the new antenna wire is being attached or how the inductor was bypassed. Can anyone clarify? Thx.
robot+more6 years ago
i don't want to mess with the signal so can i put a power antina from a car on the antena of the radio
Biotele6 years ago
What is the farthest you can transmit with this mod?
Can you also make the signal better, by making the blue wire longer?
emherrma6 years ago
Great mod!. I see a 29dB improvement
thatsmyfox6 years ago
I have a diferent version again! The unit really does need this hack though because the range is pants.(UK) Wish I had smaller fingers - I would do this one....
JakeFrost6 years ago
Just finished my upgrade of the Tunecast original, and I am amazed. Where I live there is a station on all four of the presets, now I can use it on any of them. I get about five to ten feet around the transmitter. This is my first upgrade using instructables, but not my last. Thanks
marcward866 years ago
your efforts are appreciated! i had a tunecast original, and it used to suck, but now it's awesome!!!
testoffer6 years ago
Nice instructable. Your one limitation now would be battery life. You can solve this by getting one of those cheap AC converters that outputs 3 volts DC. Cut the plug off at the end of the output line, strip the end of the wires, and hook up the + and - to the appropriate terminals of the battery connectors of the transmitter.
actualy modding that part would be pointless, i have one of these and even notice on the first picture on the bottom that little hole, its for an AC adapter. But good idea tho.
remork7 years ago
Hey, I have the same Belkin as the first commentator on this page (called Lappy). I have included a picture of it. But as my German is superrusty, I don't really understand where to solder the antenna. Is the black element with R18 on it the inductor? On what side of it should I solder de antenna? thanks :-)
h4d3z remork6 years ago
Having the same problem The board has a R18 thing How do i mod it ??
acer50506 years ago
I did a similar mod to the same unit... I live in a small trailer and its range is about half the length.. its not good for a pirate radio station lol but it'll get music to ur radio...
acer50506 years ago
I had the black tunecast 2 and the stereo wouldn't pick it up at all/very little. I had to put it on the antenna and still got tons of static.. I soldered a 1ft wire onto the black thing described in your instructable and now I can use it clear acrossed the house! thanks man :)
turbomod7 years ago
have a completely cheap and nasty virgin megastores version worth £8. have bypassed the attenuation with some 50 ohm coax got about 15feet of it stripped about 2 foot back and pulled the screen down over the insulation. hung this in my attic and was capable of receiving my signal quite clearly up to 1km away whilst stationary, this is down hill from the antenna, up hill there were too many houses blocking the signal, if i could get it higher i think I'm on to a winner, when it finally went out of signal there was another station their so i was very shocked
sevy turbomod6 years ago
Is the tunecast's power still the same,even when transmitting for a kilometre with a decent antenna? as turbomod. Would I be legally able to do this in the uk?
ReCreate sevy6 years ago
of course you can do it in the uk
sevy ReCreate6 years ago
Im not sure you can do it in the uk.From what Ive read,bypassing the attenuator would take its transmit power over the legal limit. Am I wrong??
ReCreate sevy6 years ago
i dint think so
sevy ReCreate6 years ago
The legal power limit in the uk is 50nanowatts. Can anyone tell me for sure whether bypassing the attenuator will increase its power past 50nw??:)
ReCreate sevy6 years ago
probably such a tiny thing is not capable of broadcasting more than that you could however modify a signal booster or a rf booster to to increase the nanowatts who knows?
sevy ReCreate6 years ago
Eggs act lee,who knows.
I have http://www.amazon.co.uk/LUPO-Portable-Transmitter-Modulator-Channels/dp/B000S0XBE4/ref=sr_1_3?ie=UTF8&s=electronics&qid=1233354512&sr=8-3
I can attach an external aerial anywhere on the circuitboard and I get about 300metres distance.Im looking to get around 1 kilometer (so my friend can tune to my internet station,he doesnt have internet).
My objective is to copy what turbomod did but to keep within 50nw,if possible;)
I dont want to increase the nanowatts but get the most out of 50
krunal8007 years ago
hey awesome instructable........i opened up my psp fm transmitter and connected an rc remote antenna as the aerial and the range has increased to about 5 times the original range.......once again awesome instructable dude!!!! here r some pics:
hey where did you get that transmiter? btw i have a psp except its the silver one
i cant remember exactly but i think it was from argos in uk
jb23rdmc8 years ago
Hi what do i do with the blue wire? do i need to connect it any where plz answer my question!@!@!@!@
My thoughts are that the blue wire is removed and the black wire is now being used as the wire to the antenna. This is just my speculation.
Strikah Strikah7 years ago
Sorry for double post, but if you look closely at the inductor and compare it to step 3, it has been taken out on one side
Soz but I'm still confused. Could you plz explain in a lil more detail what exactly you do with the black and blue wires? Thx I'm trying to figure it out but I'm not sure and I wanna be before I do this.
It's not like I have done this, but when I look at the pic. The blue wire has been removed and is thus no more used. The black wire, is now connected to an external antenna and is therefore connected back to the FM transmitter. If I look even closer, you see that the Inductor has been removed on one side. On that side you'll have to solder the Antenna. BUT then again, I haven't tested it yet. So if you want to do it, it's at your own risk!
Ok thank you. I started to study all the pics closely and I came to that conclusion. I hope urs works lol if you did it. I'm gunna try it on my Belkin Tunebase (the one that plugs into the base instead of the earphone jack). I have a basic understanding of circuits, I made a circuit for a flashing LED for a school project lol. I'll get some help from the 'techno' guy at school. He once made these awesome speakers and bought 'em to a carnival.
Cheers Buddy, OK well I bought two of the Belkin Tuncast II, and performed the Above on one of them. Now What I found is that on mine above the inductor (which is black and more cube shaped) is a small resistor were the black antenna is soldered in the above pic. So for testing i just used a small 10cm piece of braided wire and by hand put it on the (LCD Bottom Down Side) leg...and it improved the signal to quite a bit. Now After trying this is decided to get the solder iron out and after try to attach the new Ant to the spot basically the same as above but on the left leg of the resistor. In the end i basic shorted the resistor. So imagine the above picture were the new (black) ANT goes is actual covering up the Resistor...Now the Inductor is still in the same place and has not be moved at all and the main (blue ant) is still intact and attached. Now this works better than the other unit.(Non Mode) But still can't get than 3 meters away without signal Degradation. Should I remove the old ANT? (Was going to anyway). when you say remove the inductor do you mean just lift one leg off the board a slight. And in your above picture did you have a small Resistor under the Solder of the Black Wire(ANT)? If not what exactly are you soldering on two is there a Silk on the board at all list say R16??. the above steps that i took seem to work to my Satisfaction as i just wanted it to be in the backseat of the car or Glovebox...But on the other belkin that i have not even opened yet. I wish to perform the same mod but hopefully would be better Transmitting Distance...hence this time i will run the wire out of the device to see how much improvement it will make...Any help would be great....Basically just need to know whether i was suppose to solder the new ANT over the resistor above the inductor(Can't bee seen well enough in PIC above...but were the Black wire is attached I have a small resistor(I think it's a resistor)..Will take Pic's when have CAM Handy...
twocvbloke6 years ago
Any idea as to how to remove the auto shut-off on the TC3? It really drives me up the wall as some parts of my music go too quiet for it to handle and it craps out on me!!! I'm good with a soldering iron, but "reading" circuit boards isn't one of my things... :S
claskowski6 years ago
THANKS!!!! I have the new revision and applied this mod. All components are SMD on the TuneCast II (latest version). When looking at the circuit board, the inductor is in the same location as the first version and is marked "1R2A". I got a piece of stranded 30 AWG wire and some small shrink wrap. Removed the blue wire first and slid the shrink wrap on. Next, I attached one end of the 30 AWG wire to the inside solder pad of the inductor (pad farthest from the edge of the PCB) - attached the other end to the blue wire, shrank the wrap and reassembled. I tried it - and WOW!!!! This works so much better than before. I carried it a step further. Since the antenna goes through the connecting pigtail, I utilized this and a headphone extension cable. Attached one end to the pigtail and the other end to my Zune. Hid the wiring behind the dash, attached the transmitter near the radio (works better that way) with velcro, ran the lighter-adapter the same way. Nice little cruising rig. Thanks - never would have imagined that the inductor would do so much to cut the power.
kanamin6 years ago
I have the original tunecast (four stations, no LCD), and I was going to ask where do I solder the new antenna for the old one, but I followed the tracer from the existing antenna and it leads directly to an inductor :D the inductor on the old one and the new one are both labeled L3 by the way
4n8only6 years ago
Thxs for posting this but what do you mean "black wire", i am new to this. Is there a specific wire or will any do? i'm assuming u mean electrical wire?
Corrugator Supercilii (author)  4n8only6 years ago
It is the specific wire as identified with the colour black
defiant16 years ago
So I tried this, and while I didn't notice any real difference in range, nor do I really believe you will be doing much FM jamming with it, The sound quality is night and day. I was disappointed with the amount of static it had out of the box. Though I only paid $27 for it at Walmart. This upgrade more than cleared up the static and is arguably cleaner than local FM stations now. VERY cool ible. Just what I was looking for. I'll be recommending Belkins over the $80 units to my friends now just for the upgrade value. THANK YOU!! P.S. I didn't have a long enough wire that was small enough to solder. Am I loosing a lot of efficiency with a 45 CM wire? Should I, or can I simply add an extension? Thanks.
Small Dog Electronics is blowing out the Tunecast II for $9.99.
I just bought one so I could try this mod!
cereal16 years ago
Okay, I just went ahead and did this mod, but took the antenna wire and wrapped it up between the circuit board and the battery holder. I can hear the transmission at the other side of the house, but it's always full of static wether the Belkin is right next to the radio or across the room.
berky93 cereal16 years ago
maybe interference caused by the electronics in the device?
cereal16 years ago
So do I really need 27 inches of wire dangling from this for it to work? Or can it be wrapped up? I always use it plugged into the Car Adapter, so if I could just wrap up the wire I'll put it where the batteries usually go.
Amazing!!! I didn't remove the tunecast powerdown. Still Works Fine. I can broadcast my station all the way down my block, and then some!!! Sound is crystal clear. Although I did notice that installing the phone jack is really needed. If you want a longer audio cable save your self some time and money and buy your self a Head Phone Jack extender. Thanks for the tutorial. P.s Could you add a more powerful antenna such as a dish, larger antenna etc.. Also maybe you could even boost range by adding multiple antennas? Anny feedback would be much appreciated. Thanks Again
Cascadia7 years ago
Having a rather clunky soldering iron, I was not able to remove either end of the inductor (labeled L5 on my PCB). However, I was able to simply solder a new antenna wire to the inner side of the inductor, and after snipping the blue wire off, the thing works great.
jak067 years ago
Does any one now how to transmit a video signal?
its probably to late and you may have seen this instructable already LinK

Alienheart7 years ago
I got one of those Cygnett GrooveRide FM Transmitters. There is no screws or < O > buttons. Does anyone know how i can pry this thing open without damaging it? Is the internal the same as the Belkin Tunecast? the case has the same shape.
jgeekw7 years ago
what about one of those non-lcd screen transmitters. I bought one online that has a manual tuning knob. i don't have a pic right know, but just thought I'd ask. Would the process be generally the same?
Lappy7 years ago
German:Hi leute,befinden sich deutsche user hier im block?Irgendwie ist meine platine anders aufgebaut als die hier vorgestellte. English:Hi guys,sorry for my english. My tunecast panel is a different than your panel. Can you give me record where the new antenna soldered?
tantales Lappy7 years ago
German: Trenne das braune Antennenkabel von der Platine und löte die neue Antenne (das 70cm Kabel) an das Ende des als Inductor bezeichneten Bauteils, welches vom alten Anschluss wegzeigt. Bei dir wäre das am kleinen schwarzen Kasten das "untere" Ende. Find the connection to inductor that is not connected to the old antenna and attach the new wire over there. Don't forget to disconnect the old antenna! Should work for any similar design.
mazenka7 years ago
Quick question, can I choose what channel/frequency I want to broadcast on? Does it let you choose four? Or does it come preset.
Worked like a charm! The power leads came loose and had to resolder those on as well.
einnybug7 years ago
You ROCK! I got the Tunecast because of this Instructable. I had an FM Transmitter but i really didn't like it because it was big and bulky. Well I kind of screwed it up but it works a lot better than it did. I soldered the black wire (ground) instead of the blue wire (antenna). (i had an idiot moment i guess) Anyway, I got about 3 feet before I changed it now i walked halfway down my driveway before it started getting staticy. Some of the songs sound better than others but i think it depends on the recording and less with the FM Transmitter.
waldoctg7 years ago
Hello, I have added a antenna to the Tunecast I, but the range isn't that great. I can tell that it has improved, but it just isn't what it seems. I've seen people saying something about 70 cm (27.6 in.), what does this mean? Is it how long the antenna needs to be? Also what kind of wire should I used for the antenna, any ideas? Here's some pics too! Hit me back Thanks
real nice mod there! i just tried it and it works perfectly. even tho i accidentally broke off the inductor since i didn't have to right tools and i was feeling too lazy to go look for em...lol....but it still works very well without the inductor..but i'll stick it on later when i get the time to...thanks to The Corrugator!!
waldy7 years ago
Thank you, great mod. Cost 99p for switch + stuff I had lying round. Works wonderfully well now, no rapid battery drain & great signal regards Waldy
uberchoob7 years ago
Ok, so I added some cat5 wire for the new antenna. took two lengths of 16" which together are close as I care to get to the 31.xx inches for optimum performance on 88.1, it was heck to get it to fit, but I managed to squeeze it in without cutting out space for it. the first time I got it to fit, I forgot to disconnect the original antenna, so I had to take it apart, desolder it, and put it all together again. Final product: there is definite difference, not as much as I was hoping for, but still. I'll add more power later, but for now, I'm faced with a problem: I can't get the thing to transmit on anything but 88.7! I took apart and reassembled the thing three times to make sure I got the selector switch matched up right, and moved the switch to 88.1 before reassembling, but it still will only transmit on 88.7 I'm stumped. Any ideas?
JAYBLES8 years ago
ok so i just tried this knowing full well that the mod was for the Tunecast II and i was usin the first tunecast I. lol, everything was completely different and couldn't find the right place to add the antenna to so i just slid in a new wire where the original was and soldered a telescoping antenna to the other end. it was workin really well despite the fact that it was running on batteries. 2 songs later i hear a loud pop. the batteries poped! hahaha! no idea what happened but it was funny. the unit still works 2. thank you for the mod!
So do you still have the antenna on it and do your batteries pop ever? I have the original tunecast and i need a different antenna
i probably need the same but haven't used it since the incident. I probable wont mess with it again for sometime as i'm currently working on a few other projects and don't have time for this one, i would, however, like to hear of your discoveries if you choose to continue tinkering with the orig. tunecast. for later reference of course.
So is that the final word, with the Tunecast 1. Has anybody here successfully modified this unit? Would the addition of a transformer hardwired to the chip board solve this battery issue? I'm dieing to modify this gadget its been in a junk drawer for to long. I guess my question is, is Tunecast 1 worthy of any type of customizations, or should I seek out a Tunecast 2 worth gutting.
I have an old Tunecast, and today I was unimpressed with it's performance, so I found this thread and thought I'd give it a try.
I found the inductor that The Corrugator mentions in step 4. It's in a *very* different place. But I wired up a new antenna, cut to 70 cm (approx) which is 70 / 2.54, or 27.5 inches approx.
Initial tests show the output power is *significantly* increased. I have not had the unit heat up, or had the batteries pop.
Here's some pics. The blue wire is still attached in the photo, but it ain't now! ;)
Enjoy, peeps. Great post, Corrugator!

originaly posted by throwaway, check his post above for pics
here's mine
The Transmitter has been working great for me but I finally noticed a flaw. When I transmit to a portable stereo I notice that the volume is really weak. I can't get any big sounds when broadcasting. Did I fry something or is this part of a bigger problem?
amzzzziohi7 years ago
Cool Mod. Thx! What's the range like of the signal?
Great Article, may even gut one one day, one might consider making a 1/4 wave groundplane if you have it permanently installed in your home. Use coax to the mounting point, solder it to a pl259 chassie part, solder the exact lenght mentioned to the center and then bolt on 4 pieces to the 4 chassie nut/bolt points. (the 4 radials are same lenght as the vertical "active " element) if you like you can take solder a loop at the top og the vertical , that is, from a large piece of wire ( I like 12 wire), strip the end bend it to an Ankh like loop and solder it to itself. Electrically the thing is a straight piece of wire. Cut it measuring from the new tip, to the point needed to put into pl259 connector. this unit can be hung in a rafter or from a string across a room /hung from a tree branch. I made these for 2 meter Ham radio and put them in my attic. (sized correctly for two meters). I was on second floor and could key up repeaters for 15-20 miles, on 1 watt.
throwaway7 years ago
I have an old Tunecast, and today I was unimpressed with it's performance, so I found this thread and thought I'd give it a try.
I found the inductor that The Corrugator mentions in step 4. It's in a *very* different place. But I wired up a new antenna, cut to 70 cm (approx) which is 70 / 2.54, or 27.5 inches approx.
Initial tests show the output power is *significantly* increased. I have not had the unit heat up, or had the batteries pop.
Here's some pics. The blue wire is still attached in the photo, but it ain't now! ;)
Enjoy, peeps. Great post, Corrugator!
Hiduke737 years ago
OK, I have the Belkin Tunecast II but mine is the black one. I took it apart and it's a bit different than what is pictured. Can anyone help me with where to attach the antenna wire with the pic i've attached? I've circled where I think I should, just not sure. Any help is greatly appreciated! Thanks, T
TylerDurden8 years ago
Kudos to The Corrugator and contributors. This is an excellent mod.

I have been using my old SoundFeeder-200 for years, but it has analog tuning and drifts quite a bit based on battery-sag.

I was very skeptical, considering most of Belkin's stuff is pretty poor. This unit is not great off the shelf, but after the mod it is.

One thing you may encounter after the mod, is rapid battery depletion and low voltage from the increased load. The 12V port on my unit is nonfunctional, so I'm feeding the battery terminals with 5V from a cellphone charger. Seems to work best with a couple of NiMh batteries installed to keep the voltage at about 3.3v.

I'm using the 26.6" antenna. The results are impressive. I'm delivering a very strong signal throughout a huge 3 story, 100yr old house. I haven't done a range test outdoors yet.

I have been transmitting for years, trying many different devices and it has never been this good. It great to stream music from the net and hear it all through the house and garage. (http://floyd.wcbn.org/wcbn-mid.m3u)

Have a Nice Day,
emopants928 years ago
ok so can anyone help me do this to the tunecast 1 cuz im so lost
just look @ the back of the board, and follow the conection from "ANT" ... it will bring you to the attenuator... its located slightly below the green LED... (it may actually be c29 but im not sure of that).
Hi. I had a slightly different version of the TuneCast. Here are the Photos. Works fine.
Hi Peterjung108, I have the same unit as you and have been a little unsure where to connect the antenna. Unfortunately, I can't tell from your pictures exactly where the red wire is connected (I assume this is the new antenna connection wire) and also, is the blue wire just simply disconected? If you have a few minutes to spare I would by greatful if you could describe exactly where the red wire is connected. Kind regards Juan
laptopman8 years ago
I found this after buying the Belkin unit and finding that it would not even broadcast across my house (about 40ft).

I did not try to replace the audio cord or bypass the auto-off feature... just boost the power and include an antenna that is larger. It worked great. I can now broadcast 200-300ft (60-100m, depending on various factors). This is more than adequate to cover my house (I had my wife drive around to see what the range was) but is probably not going to put you on the air like Christian Slayter in Pump up the Volume.

Anyone with any physics or engineering class that covers electricity and magnetism learns about wavelength... so a 100MHz radio wave has a wavelength of 3m. So, a 1/4 wave antenna should then be 0.75m. Unless you have an SWR meter or something, it is not like it matters all that much as long as you are close. So, I am not sure what the issue with this was in previous posts. I noticed a significant range improvement even with a 15 inch (38cm) antenna.

P.S. 70 cm approx. equal to 27.6 inches not 2 and 3/4 inch. In a vacuum, the 1/4 wavelength would be about 85cm at 88.1MHz and 69.5cm at 107.9MHz. However, there is about a 5 percent correction factor due to the physical properties of the antenna. Since the electric signal is slower in a physical antenna, then it should be shorter by 5 percent.
now for some improvement. Make the wire 3 times as long, as in 3/4 wave length. from the ground have a one quarter wave counterpoise. should improve signal a lot. keep the hot element odd quarter wave lengths. 1,3,5,7 quarters long. the counterpoise ground wire is still ok @ 1/4 wave. the US used to limit ant to 10 feet for such broadcast devices. good luck.
Thanks for your empirical result! I live in a urban build-up area, the improvement in reception means I can recieve the FM signal 4 floors down, line of sight reception would be better of course, as you had mention. Great that you have spotted the mistake, which is always good! Cheers!
TossManual8 years ago
I have the original(I?) Tunecast, without the LCD, and the board is laid out a bit differently. Can anyone give me a clue as to what to look for to do the bypass? I can't see the label numbers on the the board for where I should re-connect the antenna. I can post a photo, if it will help. Thanks!
don't bother with the original tunecast...... it might blow up i read jaybles post and his did. i looked at mine for about an hour and said screw it. i then lost it so now i need a new one. i'm getting this one
I have a tunecsat III on order that I will immeaditly modding out in these areas. I will take lots of photos and hopefully we will build a good working transmitter.
After the modifactions. What distances are we talking about. 10'-20' 50' 100'. or has anyone checked?
10' or more line of sight. I didn't close doors or anything. I mostly use it in my car.
ekolesar8 years ago
I added a longer audio instead of a jack and I didn't do the power mod since I only use it in my car with the car adapter. The antenna mod was the biggest help.
Wildscot8 years ago
Firstly excuse my total ignorance here. But hey, what better way to learn than pulling things apart!
I'm keen to have a go at this but it's not a genuine Belkin that I have, it's a Chao Yu version, see here. I'd assumed that as they were identical outside they'd be the same inside, they're similar but not the same.
I've no access to a soldering iron and unfortunately I can't get at the 'business' side of the board due to the battery contacts being soldered through the board. I'm wondering if I can simply snip the blue wire and attach a new aerial to the 'ANT' hole. I know it's hard to say for sure but any educated guess would be appreciated. I'm aiming for roughly 60cm to transmit on 87.5 right?
Corrugator Supercilii (author)  Wildscot8 years ago
Hi, it does look similar but I can't be sure so better safe than sorry.
Hi, Thanks for the advice - but I decided to go for it anyway!
It's extremely rough and ready and because of that I'm having real difficulties getting the buttons to work once I force the case closed.
But It works! The transmission is as clear as ever and judging by my extremely unscientific testing it seems to give a good signal for roughly twice the distance that it did before.
It should be clear to anyone reading the instructable what I've done but for anyone else that wants to try it's as simple as cutting the blue wire from the headphone jack, attaching a new wire to the wee hole marked 'ANT' and connecting that to a new antenna - in this case ripped off of an old tape/radio deck.
Thanks Corrugator, all I need now is someone with a hot glue gun and a soldering iron to tidy it up a bit. Any takers in Edinburgh, there's a couple of pints in it for you.
Thanks for sharing your solution! I also have the Chao Yu from eBay - nice piece of kit, especially with the USB charger (as it takes 5v). I tried this mod (reception is great at home or in the office, but awful in my car) but wondered if you could help me out. Soldering a wire to the ANT hole gives a strong FM signal (tested by playing silence) but connecting a music source results in a very thin sound with, for example, vocals almost missing entirely. Touching the blue ground/antenna wire from the original lead to my new antenna (a 1m 3.5m jack to jack lead with the ends cut off) clears this up nicely, but I don't seem to get any better range when I do this. I also still get the high frequency ringing noise when bass kicks in, despite fiddling with the input level from the MP3 player and EQ settings (as this unit tends to over-emphasise bass). Am I missing any extra steps, do you think? After all my work I seem to be no better off!
Hi, Sorry but I'm no help to you, my technical knowledge is nil. I had 2 of these around and just decided to take a gamble. I hope you haven't knackered your transmitter. Perhaps I didn't make it very clear that it was an optimistic but probably misguided effort that seemed to work out. For me at least... Hopefully someone here with some know how might be able to step in?
Here we go:

Now I just need to work out what it means for me! Looks like I have some more soldering to do.
It's not knackered at all, but I suspect that what I have done has made no improvement. I'm trying to find a link from another person's site that I stumbled across - they seemed to know what they were doing with these things! I'll post it if I get it.
And the auto power disable is also slightly different for this model. The resistor is connected between the two terminals of the transistor. Here shown without switch - always on.
mutant8 years ago
I did this once before. With the tunecast as a matter of fact. I used one of the the antennas from an old set of tv bunny ears. It helped a lot. I made the antenna poke out where the cord used to clip in. I did not however disable the powering down. I hate that. If I just wanna switch songs or something, it cuts off on me and I have to turn it back on. Thanks for the tip. Only problem is I accidentally stepped on mine a while back. Might mod my other transmitter. I'll post pics here to demonstrate this concept with other devices. P.S. If you really want some good transmission range, use an extension cord with the end cut off. You can also attach a colander to the end where the plug used to be. I've done that with a small AM crystal transmitter and It picked up all over my neighborhood. Although it might have violated a few laws. But hey, where's the fun if there is no risk involved right?!
vf_pedro mutant8 years ago
hey i want to boost my signal without having a solder or an ability to use one... can i just clip the wire thats on the antenna and add a bunny ear antenna thats retractable to it... (in short can i just hook the antenna wire to a real antenna and would that help) email me response (badgerboy900@aol.com)
mutant vf_pedro8 years ago
sure, I guess. I just used hot glue on mine. Worked like a charm.
TallAlex8 years ago
USB ports can provide you with 5 volts...maybe a future hack?
palli8 years ago
I bought this product and it works great, BUT the display is not very good. After only 2 weeks of usage few dots on it have stopped to shown. One the first digit befor the dot (.) are some dots missing. But still I can see on what frequency it's adjusted. That's the only negative thing I can say about this product.
trebuchet038 years ago
I am sooo glad you actually calculated the length of antenna wire. I was honestly expecting another kid to just add an arbitrary amount of wire for the hit or more likely miss solution :P

For your information... you can do superpostion by surrounding the character to raise with carats.

Such as: 3e8/108e6
Confused on the antenna length bits.

If the antenna wire has to be a specific length, then wouldn't the retractable antenna be detrimental to the hack?

*edit* I am a backwards American, we use inches still. Once I converted it
70 centimeters = 27.5590551 inches then everything became clearer.
Yeah... NASA made the same mistake with a space probe and send a few million dollars worth of equipment off course into infinity and beyond.

70 cm approx. equal to 2 and 3/4 inch, 1 inch = 25.4mm, 2.54cm
Yeah, but you have to remember that NASA is working with distances that if you get a centimeter off at the start it can end up causing a million mile difference in the end. You were talking about adding a length of wire as an antenna, this might be an idiotic question but where do you solder the new antenna to?
Great Hack! I tried and when I was removing the inductor the connection came off with it. Is the device trashed or is there a fix? There is no metal left at all. I'm screwed right? Give it to me straight. Any help? Thanks
Not really , if you look at the photo on step 4, I believe the inductor is connected with a capacitor, ( labeled C21? ) get hold of a multi-meter, switch to continuity test or resistor test, probe around that PCB connection around the inductor you should be able to get an alternative connection for the antenna. The inductor is after all, a 2 terminal device, so both ends has to go somewhere, lookout for the PCB trace or via hole. And you really need a soldering iron for the task of removing the inductor, do not pry it with a piler. Do be careful.
I did use a soldering iron. I just wasn't careful. Thanks for the help.
To anybody who tries this: When you are taking the board out of the case, particularly the front portion make sure the LCD display does not stick to the case. Mine did and the delicate plastic ribbon that attaches the LCD to the circuit board came off very easily. Too easily. Its not easy to repair. I probably will not be able to fix it. YMMV
Yeah I ended up chucking it.
fer8 years ago
The Corrugator:

Can you please post a more detailed image or (better) a drawing of where exactily to attach the cable antenna? This is because in DSCO1110 image it's difficult to see where to make the soldering.

Corrugator Supercilii (author)  fer8 years ago
Hi, Sorry it couldn't be clearer, but I dread opening it once again. On the image that you mention, the black wire (which will be your new antenna) is soldered onto one end of where the inductor use to sit. See the additional images on step 3 for comparison, cheers!
I opend it up and I saw a coil, which was covered in thick goo material. I scraped off the goo material and opened up the coil so that it looks more like a straight wire, not a coil. I am guessing that should take the inductance off. I put all that back and it does not work. Am I making some mistake here? I scraped it off carefully, I know I did not break anything else.
do you have a picture? and how did you know it was a coil if it was covered in goo?
I'm not much of a radio person, but just to guess, you probably took apart part of the electromagnetic device that is the core of radio. I'm not really sure though, considering IC's make a big difference when it comes to modern circuits. Either way, you probably took apart something that shouldn't have been removed, especially considering that it doesn't work any longer.
mello8 years ago
Thanks dude! I just bought one of these things and this is exactly what I've been looking for.
crapflinger8 years ago
got one of these for my GF at some point...and it sucked so badly...horrible reception even next to the radio...just...junk...removing the attenuation has to help... you weren't very clear on the "inductor" did you just desolder one end? i would imagine you could desolder the entire thing right? now all it needs is a power jack so that you don't have to worry about the batteries
Mine has a car power adapter with it. Did yours not have one?
nope..mine didn't have anything close...it did...i think have a port for it now that i'm thinking about it...
Yes, you can take away the whole inductor, chuck it out the windows or ideally, choose suitable ways of recycling. But take note where you resolder the antenna wire, as indicated on the photo. Cheers!
anyone care to post an instructable for how to do this, at least bypassing the attenuation, to a griffen roadtrip?