iPhone 4 signal strength in dBm?

[firewood]

Anyone know how to get a read-out of the current cellular signal strength in dBm on an iPhone 4?

 

[MarkTTU]

No, but I'd sure like to!

 

[Cyclone Chris]

For some reason I can click on my bars and it swaps from bars to dbm on my iphone 4. This has happened ever since I had backed up my Jailbroken 3GS while it was showing dbm.

Every restore from backup (non jailbroken) from there on out resulted in the dbm option without punching in any type of code.

It's weird, but I love it. I noticed that the iPhone 4 sometimes shows 2 bars at -113.

 

[AustinSTI]

No, but I'd sure like to!

+1

 

[ejfraser]

Well, this used to work, but now it doesn't seem to be.

But give it a shot either way I guess:

Access the iPhone’s Field Test mode by typing *3001#12345#* in the phone’s keypad and press dial. This will bring up the Field Test menu.

 

[link575]

Use ^ that sequence but on a phone with lower than iOS4 and while in the field test mode
if on 3.x.x hold sleep button until it prompts to shut off then let go and hold the home button until it force quits the field test mode.
if on 2.x.x hold home button until force quit

make a back up on itunes and then restore from that back up on the iphone 4. You will just need to touch the signal to switch between bars and dBm

 

[iTouch]

RF meter/multimeter. Bench test or using the machines that were used in production.