How do I check my WiFi network strength with an iPhone?

I have an iPhone. How do I check my WiFi network strength and verify that MySpool devices can use it?

Here is the procedure to setup AirPort Utility and check your network strength:

1. Install
2. Do not launch application yet
3. Go to Settings -> AirPort Utility and enable "Wi-Fi Scanner"
4. Go to your deployment location and launch AirPort Utility
5. In the top right corner tap "Wi-Fi Scan"
6. In the top right corner tap "Scan"
7. Find your 2.4 GHz network in the list of networks and read the RSSI value. Your device will work with a network showing a value greater than -70dBm  

Note:  if you have an android  phone, install "Wifi Signal Meter" app from the Play Store.  When it is installed, connect your phone to your 2.4GHz network, go to your deployment location and launch "Wifi Siignal Meter". You should see signal strength when the app starts.