Make sure both of the screws are tight on the bottom (be careful not to strip it) or try to switch it. If this doesn't work we can diagnose the problem further.

I recall four metal "fingers" on the speaker enclosure that is supposed to be related to signal reception. The fingers are supposed to be under the lip, not ontop of the board. I also know of that antenna connector close to the battery connector. Those are the only things I can think of that is antenna related.

all of screws is up, and four metal fingers on the speaker enclosure is fine,

where is antenna connector?

Pretty easy to solve this,

There is a welder metal area on the top of the speakers enclosure, just separate it from the four metal fingers under it, this welder metal area is in circuit touch with one or more from these metal fingers which affecting the reception signal,

by smoothly separating them you'll retrieve your full signal back.

hope this helps

i Hasave the same problem and i tried everything that is listed in here and still no service

Update

@walter: thanks man, is there any specific ones that i have to clean

@daniel: yes, double check that it is connected

The oils on your fingers have the potential to cause wireless interference issues. As stated throughout our iPhone 4 guides: "Before reassembly, be sure to clean all metal-to-metal contact points with a de-greaser such as windex. The oils on your fingers have the potential to cause wireless interference issues." Hope this helps.

@walter: thanks man, is there any specific ones that i have to clean

@daniel: yes, double check that it is connected

i just finished cleaning every connection on it, its still ask no service :(

Unfortunatelly i have the same problem :s

It just happened when i opened my iphone to try to fix my voice sending problem during a voicecall.

I've figured out the reason of my voice sending problem (it's about the sockets) but now i have the reception problem :(((

Are there any other connections of gsm antenna with other parts?

And the antenna connector near the battery socket..Does it effect Wi-Fi and Gsm both or just one of them?

i had some problem, no gsm signal and very weak wifi, got strerng only when very close than router.

I think in buy one antenna parts but worry if problem is in logicalboard, whats do now?

Thanks

People. Check that you did not accidently break your antenna inductor on the logicboard.

seems to happen to many of us:

this is what i am talking about (pic on page) http://www.ifixit.com/Answers/View/50969...

I has problem only with Wifi, the signal is very weak, powefull only when side of router and when lift room the signal lost. I buy one wifi antenna new and change, but not happens, whats can i do now? thanks

Yes. All. updated to 4.3.3 and all tips alreadyu buy one antenna replace and changed and notthing im fell very very bad with this iphone now, im on Brazil and here has no official apple assistence, and this iphone is ATT so very sad. But i has some hope can found one way to fix that, afterall i payed about 900usd for that, not fair dont work wifi...

thanks in advance

I has fix my gsm signal using this instruction

http://www.ifixit.com/Answers/View/50969...

I use spesial glue for contacts, it can pass voltage. Usually such glue you can find in car shop and look for a glue which repair back window lines to warm it. Hope you understand me.

Thank you! It is my 1 post here=)

Bridging the 2 solder points with a conductive trace pen worked for me. A precision solder bridge should also work.

replace it with a new blue iphone coil that will fix the problem

you can buy a new blue coil here for the repair

update video tutorial on how to change the blue coil on youtube.

If you have a repeater installer in town, they'll usually come do a full signal analysis and then just FIX IT. These guys cover people around San Antonio n stuff, but they answer questions pretty well. --> http://www.getmesignal.com/

http://www.ifixit.com/Answers/View/37807... is a post last night that i made. it will help you resolve the problem. its an easy fix