Bluetooth range booster (and wifi).

Recently i got me a pair of bluetooth headphones, my purpose was to use them with my cell phone. It came as a surprise that the sound was choppy (not sure if it's the right word but the sound stutters). with the phone on my pocket and the earphones on my head (yes i like to do it that way, i tried with the phone on my nose and the earphones on my feet and, somehow,  it didn't fell right). I checked the earphones with my ipad and the range was correct, around 10m (that is 33 feet).

I suppose my cell phone is the one to be blamed, it is a chinese made Zopo ZP980 (codenamed Potato by my wife). So what are my choices?

On the first place i decided to open up my phone and take a look.

This is where the antenna should be.

##################WARNING-DISCLAIMER: ###########################

What you are about to read will most likely render your phone useless, it's probably ilegal and bamby's mother's killers¹ are supposed to have performed this procedure. Proceed at your own risk, i decline any responsability for the damages.

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After opening the phone I saw where the antenna for the bluetooth (and wifi) was supposed to be. there was a sticker (see picture) where the antenna was suppossed to be. The antenna was absolutely useless (if you ask me that is not an antenna, only the connection). Then i remembered that the wifi signal was between poor and worse.

if your phone doesn't have an antenna what should you do, you should build yourself one.

what is the wavelength of bluetooth?? Well, bluetooth's frequency is 2,3 GHz. That is aprox. 13 cm, so a quarter wavelength would be 3 cm (1,2 inches). I took a cable of 2,5 cm (1 inch) length (i suppossed that the track and connector will make up for the 5 mm (0,2 inches) missing. The cable was sticked on the connector (see pic), no soldering or glue was used.

That red wire is acting as a supplementary antenna!!!

The result on my case YMMV² was that both bluetooth's and wifi's signal was boosted tenthfold.

Bluetooth is useful at 9 m distance (10 yards) and wifi's usable on my whole home (before the fix the signal died everywhere except the living, where the router is).

My results are absolutely not scientific, i only tried on my cell. I should check bluettoth's performance varying the length of the cable used as antenna and determine the optimum's length. I will not do that because something that I have previously probed is that tinkering too much with your electronics equipment wil end up breaking it. I try to reduce my tinkering to a minimum.

The antenna length would only be useful for this model because the cooper length on the circuit's board should be taken into account.

the moral of the story is that if your bluetooth's signal is very bad it could be blamed on the antenna: defective or nonexistent. In that case it might be fixed (might, might might) at home through a diy procedure. The one described above is extremely simple but needs some basic skills that can break your phone.

Remember that you probably can live without a bluetooth (or wifi) connection but you probably won't be able to go through without a working phone.

Good luck and please comment if you think the info was useful to you, specially if you can reproduce the results (on this same model or other).

¹ Sorry, in Spain Bambi's mother''s killers represent everything that is evil.

²YMMV - Your mileage may vary