Signal: REAL Signal Strength, Cell Info & More
One of the first things I installed after I jailbroke my iPhone 4 was @planetbeing's Signal
app. It not only provides easy access to cell tower data and RF metrics that have been unavailable in iOS 4 due to the loss of FieldTest.app, but it gives you a way to say 'thank you' to a member of the Dev-Team. As @MuscleNerd tweeted
when the app went live on Cydia, it's almost a community service to support @planetbeing in this way since "*everyone* benefits if he stays interested in baseband stuff." But it's not philanthropy to get this app, especially if you're interested in RF or if you have an unlocked iPhone and are trying to figure out which carrier gives you the best signal.
Signal presents the location and receive signal strength from all nearby towers in a very intuitive Google Maps overlay. Your current 3G base station is shown as a red dot, with the actual real-time received signal strength shown in dBm inside the dot. Other UMTS/GSM cells are displayed as blue dots. Adjacent cells offering only EDGE service are shown in gray. If the app can't determine the signal strength, it will just show the letter E inside those dots. You may just see your primary cell when you first launch the app, but @planetbeing says to let it run for a few hours and it will cache the locations of all the bases it can find, which will display as yellow dots on your map.
For true wireless geeks, there is an info page that shows details on all the cells that the app has been able to identify. The info page shows not only raw signal strength, but also RSCP, which is the power level once the signal has been descrambled. There's a ton of other data, such as the uplink and downlink channels, scrambling code and Ec/N0 (energy per codeword over the noise floor, basically signal-to-noise ratio). And just for fun, there's also a little "Death Grip game" you can play to see if you can kill your signal by holding your phone the wrong way.
Since they don't accept donations
, spending $5 on this well-made app is a way of saying thanks to the Dev-Team and helping support one of the most talented iPhone hackers we've got.