DBM signal strength instead of bars

I read about this somewhere and thought it was useful.
I am not a big fan of the (number of bars) method of reporting signal strength.
They are so generalized as to be not vary useful.
So I went hunting and found a note about getting signal strength in DBM instead.
There is a field test app hidden on the phone and it will change your signal report to DBM.
I went looking for this info mainly because I was testing a cell repeater kit for improving coverage inside a building.
Making the change to DBM over bars helped.
Anything better than minus 75 seems to be great.
I can make calls at minus 95 but much lower than that and it is hit or miss.
So here is how to set it.
From your phone dial
*3001#12345#*
That is
(star, digits 3 0 0 1 pound sign digits 1 2 3 4 5 pound star).
Then hit the call button and you are in field test mode.Now touching the signal strength with a double tap will switch back and forth between DBM and bars.
If you want to make this change part of your normal operations then do this.
Press and hold screen lock until you get the slide to turn off message.
Don't do that.
Instead hold the home button until you have your home screen back.
Now your signal strength is in DBM.
Single finger double tap the signal strength to switch back and forth between DBM and bars.
If you just want to check it out then you exit the mode with the home button instead of using the screen lock method.
Note that some web sites say this mode was not available on all versions of IOS.

Tags: 

Disclaimer

The guide on this page has generously been submitted by a member of the AppleVis community. As AppleVis is a community-powered website, we make no guarantee, either express or implied, of the accuracy or completeness of the information contained in this guide.

13 Comments

RE DBM

So everyone knows, this does work in IOS 5.1.1 on iPhone 4S.

What is DBM

I read this post and tried it, simpley because it sounded interesting. However, I have to wonder, What exactly is DBM? I think I see how the signal strength information is better than x out of y bars, but any feedback would be good. Thanks much.

Wi-fi?

Can you get dbm for wi-fi? I tried and could not figure out how. Also, what else can you do with this hidden app? Are there any other hidden apps?

Hi, I don't know of a command

Hi,
I don't know of a command you can put in to get dbm for wifi.
However if people are prepared to jailbreak there iPhone, you can install sbsettings, from cydia, in there is an option you can enable to get dbm for wifi, so I assume there has to be a legitimate command that can be entered to get dbm for wifi.
I actually don't use any of sbsettings features apart from this one, and I have found you can remove sbsettings after enabling the dbm for wifi and it continues to work after removing the package.
Also it even works on a non jailbroken iPhone if you restore from a backup created from a jailbroken iPhone you can still get wifi dbm.

AT&T reading more honest then sprint?

I tried this and the humor I enjoyed was Sprint was about -105 and showed 5 bars where AT&T was -100 and showed 3. Lower equals more bars? Um, I don't think so.

I only use dbm measurement

I only use dbm measurement instead of bars.
The higher the number the poorer the quality of your signal, so for example a signal of -60 is better than a signal of -90. Bars actually tell you nothing useful at all.

Workaround

Hi. I googled around a bit and your right there's no way to do it. Jail breaking scares me so I'll just shut up and deal.
It is possible to see this info in settings under wifi. A workaround if not a fantastic solution.
ps sorry for bad spelling and typos!!

Interesting. I had heard of

Interesting. I had heard of this since about 2 years ago. My question is this. If you no longer wnat it a perminant part of the home screen how do you disable it? is there a code you have to dial? I wanbt to play with this but what if I want to turn it off now that it would be perminant? Reboot the phone I'm guessing.

Thanks all.

Reset to signal bars

If you used the above method to make the change permanent, it can be undone by repeating the process and just pressing the home button when you open the field test mode.

Intersting. I'll have to play

Intersting. I'll have to play wiht this. I never thought I would use integers again, but ah well, it works. lol!

Re: lower bars better

Re: lower bars better signal.

Hi John, actually it isn't so cut and dry to say lower bars is lower quality when you cross technological lines such as a different carrier technology (CDMA, GSM, LTE, etc). Almost invariably the newer the technology is the better it is at processing a signal at a level closer to the noise floor. A term used in the mobility realm is SNR or Signal-to-noise ratio. The lower the tolerable SNR for a given technology the higher the 'quality' rating a given dBm value will be assessed at. Therefore, LTE at around -100 dBm is considered middle of the road (this is an *amazing* feat of engineering I might add) whereas Sprint on an advanced CDMA technology considers that to be an excellent value, also amazing.

I recommend, so that you can see this in action (and just how poor older tech is), is to turn off the '3G' or 'LTE' functionality in settings and see the numbers that come up.

Basically, the quality of data communications we receive at -100 dBm in the current age is just jaw dropping when you understand the history.

Regards.

Source: past education/experience/employment

this is very cool

hiya, i've known about this for some time. don't use it much myself, but have done in the past. i am on LTE, and at -100 to -110, i have a downlink speed of anywhere up to 44 mbps. so that's doing pretty good. ahaha