Although the network, 3G, and 4G icons that reside in the HTC EVO's status bar provide a general indication of signal strength, they can often be the cause of frustration when you're not seeing the kind of performance you might expect from a "full bar" signal. There are many factors affecting speed/performance/etc. when you supposedly have a full signal, but one way to manage your expectations is to know the actual signal strength in terms of an RSSI measurement.
There are several apps out there that let you view WiFi signal strength (e.g., WiFi Analyzer), but did you know that you can view RSSI measurements of the EVO's network/cell, 3G, and 4G radios right out of the box? All the information (plus some other details) can be found in a hidden setting called Field Trial.
To access it, just dial ##debug# on your phone. You'll see the screen shown above (that's the 7" dual-screened Toshiba Libretto W100 behind the EVO in the photo) almost as soon as you lift your finger from the final #.
Tap on "1X Engineering" to view 1xRTT info, "EVDO Engineering" for 3G info, and "WiMAX Engineering" for 4G info.
What you're looking for in the list that will appear is "RX Power," which is the RSSI. You'll see a number between around -100 dbm and -50 dbm. The closer to -50 dbm you are, the stronger your signal is. I believe -50 dbm is considered to be a full signal. The best I have seen on my EVO is -65 dbm, though even at -72 dbm my status bar icon still shows full strength.
There’s an app called RealSignal that’ll show you two of your RSSI values as taskbar icons. Useful for tracking data signal since that is technically independent from your voice radio strength.
Thanks to you and Jenn for the heads up!
RSSI is really a value of signal QUALITY, the highest (numerically lowest) Ive ever seen on a 4G signal has been -34db, but anything below -62db means you might as well be next to the tower.
Average range is -68 to -76, with anything in the -80′s and -90′s meaning high interference in the area. But its not really an indicator of signal strength.
The composite CINR value is what is looked at, which is a composite of Upload and Download components of carrier signal strength. If you could check the diagnostics of your 4G radio, you would look at your CINR score. Anything below a 9 is bad. Avg “good” range on that value is 12-35, which you should easily connect and surf with that.
For a quick and dirty look as to how your signal is doing is to look at the CINR score for strength, and the RSSI value indicates the quality of conditions around you.
Thanks a lot!
Here are some SPRINT phone codes that I found from a google search.
USE AT YOUR OWN RISK. Some do not work on my Evo.
Code Number Program Run on the Sprint 6700
##DIAG# 3424 “DMRouter.exe”
##DEBUG# 33284 “FieldTrial.exe”
#HELP# 4357 “EPST.exe #4357″
##PRL# 775 “EPST.exe ##775″
##DATA# 3282 “EPST.exe ##3282″
##PREV# 7738 “EPST.exe ##7738″
##AKEY# 2539 “EPST.exe ##2539″
##VOCODER# 8626337 “EPST.exe ##8626337″
##RTN# 786 “EPST.exe ##786″
##pst# 778 “EPST.exe ##778″