Low-Cost, Handheld, RF Spectrum Analyzers
Touchstone Mobile for Android devices is the first (and only) mobile application for RF Explorer handheld spectrum analyzers. Like Touchstone and Touchstone-Pro, the Touchstone Mobile app turns data collected from RF Explorer spectrum analyzers into highly graphical charts and displays, enabling users to more readily visualize the RF environment, monitor RF signals, troubleshoot RF issues, and detect sources of RF interference.
Touchstone Mobile is available from Google's Play Store. For evaluation purposes the app is free to download and install and can be run in "Demo" mode without an RF Explorer device. A software license key costs $49 USD and enables the app to use an RF Explorer device to collect spectrum trace data in real-time.
In order for an Android device to use Touchstone Mobile to communicate with an RF Explorer device we have identified 4 requirements:
 The Android device must be running version 4.1 (Jelly Bean) of the OS, or higher.
 The output power on the Android device's USB port should be 5V.
 USB Host Mode must be enabled on your Android device.
 A USB OTG (On-The-Go) cable is used to connect the Android device to the mini-USB port on RF Explorer.
For more information: USB Host Mode (Android) and the OTG USB Extension.
Documentation for Touchstone Mobile can be found here.
Touchstone Mobile continuously scans and samples the signal strength (dBm) of frequencies in the range the user has specified. In the 'Spectrum Trace' view the signal strength data (in dBm) is displayed as a function of frequency.
The 'Waterfall History' view is also known as a "heatmap" graph. It provides a color-based visualization of the RF level and activity over time. As signal levels for specific frequencies or frequency ranges increase and decrease, the waterfall map varies its colors. This feature provides a quick glance back into the sweep history to identify aberrations or fluctuation in frequency levels.
The 'Density Map' shows accumulated RF energy as a function of frequency. The power of the signal strength in dBm is shown across the frequency span. A signal strength with a relatively low occurrence is 'blueish' in color, whereas increasingly brighter colors are used for signal strengths that occur more frequently. Signal strengths that occur most often are 'redish' in color. Over time, this spectral view will approximate the steady-state RF energy signature or pattern of a given environment.
'Monitored Frequencies' mode allows you to monitor specific frequencies. For example, in the setting of a live performance where it is important to monitor the channels that have been assigned to wireless audio devices, this feature can be used to ensure those channels are not being impacted by other sources of RF transmissions. Alternatively, if there are wireless devices that transmit at specific frequencies and you wish to monitor their transmissions, then this mode can be used to verify they are currently operating.
RF Explorer spectrum analyzer is a very unique device. Together with Touchstone Mobile software you now have an RF diagnostic tool unmatched in price and performance. Armed with the ability to monitor RF signals, detect RF interference and view all RF activity that occurs in your environment, solving wireless problems just got a whole lot easier.
Though a majority of the latest Android devices are distributed with USB Host Mode enabled by default -- there are still many that are not. As long as your device is running version 4.1 (Jelly Bean) or later of the Android operating system, then USB Host Mode can be enabled by copying a configuration file to a system folder. If USB Host Mode is not currently enabled on your Android device, then please follow these instructions: Instructions to enable USB Host Mode
We have developed a simple tool to aid in determining whether a particular Android device is suitable for use with RF Explorer. The app is free and available from the Google Play Store.
We strongly encourage all customers to check-out this tool before purchasing the Touchstone Mobile software.
OTG Test For RF Explorer