12-14-2016 11:44 AM
Some of you are aware of the Field Test Mode on your iPhone. Entering that mode will display the signal strength in dB instead of those vague "bars". Problem was that it would revert back to the bars if you did anything else.
So for all you people who would prefer an actual signal strength displayed all the time, follow this procedure:
1. Dial *3001#12345#* just like before. The Field Test Mode should open and you should see dB's displayed instead of bars.
Now here's the hack!
2. Hold the Power button down until the "slide to power down" prompt comes up.
3. Hold the Home button down and while doing so, start mashing the volume up and down buttons quickly.
4. If you do the mashing correctly, your phone should return to the field test mode and the signal strength is now in dB's.
5. It will continue to display in dB's unless you touch the very top left-hand corner of the display. You should be able to toggle between bars and the dB reading.
12-14-2016 3:56 PM
@Avedis53 - interesting. I thought that technique was already available, or somthing similar. I think I did that quite some time ago. Anyway, using "hack" may be discomforting to some because you're not really hacking your phone so you can't damage it in anyway. Just enabling a "hidden" feature
12-14-2016 7:00 PM
The "hack" has probably been around for some time but I didn't see it until today. I've played with the Field Test Mode for a long time but it always bugged me that the dB's wouldn't remain on. Now I display dB's all the time. Much more useful information than those stupid bars.
Oh, and down in my basement where only WiFi-C can complete a call, I get -123 dB.
dB Signal - A basic guide
•-50 to -60 (very strong, near a cell tower)
•-60 to -70 (extremely good, rare)
•-80 to -85 (normal downtown)
•-90 to -95 (getting on the weak side)
•-95 to -98 (weak, dropping calls)
•-98 to -100 (bad, hard to stay connected)
•-100+ (basically no usable signal)
To return to the default bars permanently, follow these steps:
Step 1: Dial *3001#12345#* on your iPhone then press Call.
Step 2: Press on your Home Button once.
12-14-2016 8:21 PM
@Avedis53 - nice. I should probably add that to the Guide. I like the Signal guide. If I remember correctly when monitoring LTE signal strength the dB readings can lose some accuracy because of the way the signal is calculated. I may have to dust off my notes and see what I can find. Just checked my phone and I'm getting about -84dB, which is not bad for right now. What I really want to find out is what the other areas listed under the Field Test mean.
12-15-2016 3:52 PM
Most of the other information available while in Field Test Mode requires a degree in telecommunications to understand.
12-15-2016 4:44 PM
12-15-2016 4:49 PM
Sort of like having a SME to help with our Mcell questions that was promised....oh.....15 or so months ago.
12-15-2016 5:25 PM
Yep I think I'd need to get with an Apple engineer though to know for sure how to interpret the readings. There is a cool little app for the Android folks that actually gives more useful info for those who are so inclined.
06-15-2017 8:22 AM
@kurgan0789 - but you can still get the -dB reading if you want to see what your signal strength actually is. It is intended as a test mode, not a permanent function.
06-15-2017 8:52 AM
I find that comment interesting as I am running iOS 10.3.2 on my iPhone 6 and I have the Field Test Mode activated to indicate dB's continuously. I've even rebooted my phone a few times and it still displays the dB readings. I can still tap the dB reading to switch the display back and forth between dB and signal bars.
Perhaps you aren't inputting the "hack" properly? Which model of phone are you trying to do this on?
06-15-2017 9:30 AM
06-15-2017 12:26 PM
Thanks for the responses. I don't get it either. I have an iPhone 7 Plus, but why should that matter? I'm doing this:
I did try the volume button up/down trick, but it wouldn't take. I tried to find a how-to closest to recent times as possible. I tried calling AT&T tech support (advanced Network support), but I got hung up on twice and just gave up.
06-15-2017 12:36 PM
@kurgan0789 - yep. That works on my SE. Could be something to do with the newer iPhone 7 hardware. Calling AT&T support will get you nowhere. They won't have a clue.