Help How to disable 3G. Weak signal when showing 3G...

[Despotes]

When my Captivate shows the 3G symbol my bars drop from none to maybe 1 bar and signal strength will drop down to -117 to 0 dBm. When the 3G symbol disappears my signal strength bars go up to 4. This is in my home.
WHY does this happen and how can I disable 3G so I can use my phone as a phone and get somewhat decent call quality?

Update

I found this:

Dial *#*#197328640#*#*
Select [1] DEBUG SCREEN
Select [8] PHONE CONTROL
Select [4] UE STATE CONTROL

If you want 2G, select:
[3] CHANGE RAT TO GSM

If you want 3G, select:
[2] CHANGE RAT TO WCDMA

It works 'til you reboot.

 

[CrimsonPride]

if youre on 2.2 you can hold the power button and select 'data network mode' and it will disable it

 

[Despotes]

if youre on 2.2 you can hold the power button and select 'data network mode' and it will disable it

Will it only disable 3G not Edge (2G)?

 

[CrimsonPride]

Will it only disable 3G not Edge (2G)?

no it disables the entire data network

 

[Despotes]

no it disables the entire data network

Don't want that. I still need data just not 3G.

 

[LMaxwell]

The default setting is actually Dual, which isn't an option when using the code. To set the phone back to default, turn Flight Mode on and off or restart the phone.