Well, here I am. As I promised, this is the translation of the article in frandroid forum. Take care of what you do...or what you TRY to do. I'm not responsible of any damage that could happen to your phone...including a total blast of the phone, or its morphing into an alien.
ANyway, I'm translating only the instruction and the most important comments. And I'm also linking the imgs since I cannot copy&paste them in [img] format or the page will get enormous.
cloudy weather, fixed in 2s, no signal loss, satellite SNR stable, accuracy around 18mt and 8mt, calculated at countryside, forest and around the city near to the buildings (accuracy around 8mt and 11mt for 95% of the time)
1: first tests
this is the general principle
take away the back cover
take away the antenna (take care of the wifi antenna whichi is near)
take away the connectors
solder a Ø0.5 et 5mm long cable
tinplate the antenna
solder the antenna.
[in other words: replace the original antenna with a new one you gonna create DIY, and sold it]
Be careful: this method is not for everyone, and it is risky to follow it (realised with a 1W solder iron point)
2: no-dismount version. (version Dany)
I realised Orefie's antenna (the previous one...) with an alluminium lid cut with very thin scissors
I isolated the antenna connection as in this image, the yellow part will have to make contact with Orefie's antenna: just leave the only necessary part in contact and isolate the rest with insulating tape.
[imaegs' instruction translation]
1mm cut to isolate antenna's contact
part in contact with Orefie's antenna
green parts must be isolated with insulating tape
Then isolate the antenna, leave only the connection
Only the contact must remain, in order to connect the new antenna
Then I isolated the original antenna with blue insulating tape and fixed Orefie's antenna with 2 little pieces of red insulating tape.
Excellent results, no modification on the back cover nor in other parts.
Behind the windshield SNR signal was more than 40 in some satellites, most was more than 30.
Accuracy when still between 8mt and 9 mt, when moving between 12mt and 18mt, TomTom CoPilot and Primo work flawless and the route is perfect.
The signal decreases slightly when moving, but it is still accurate.
This is a screen of the final result
Antenna fixed with insulating tape
Connection between B92 / orefie's antenna
The antenna will replace the original one so it is necessary to isolate the part in contact with the connectors, a little cut is enough, it maybe not work with 2 antennas
For those who have not scratched the whole antenna:
just scratch the only part in contact, and don't forget to unsolder the original antenna as below
scratch here for new B92 antennas
Then unsould the original antenna with 2 tiny cuts and remove the copper
Isolate the antenna with insulating tape, and leave just the part in contact.