Protecting your instrument



RF Explorer is a very sensitive device. It can detect signals as low as -120dBm, which is 10E-12mW or 9nA over a 50ohm load.

This extreme sensitivity comes at the price of fragility; your device needs care handling and protection in order to run for many years without problems.

Most RF technicians know the RF instruments have to be protected in order to survive the high Electro Magnetic (EM) fields that may be in the environment. Expensive instruments like $50,000 full sized Spectrum Analyzers and Signal Analyzers comes with a long list of handling procedures the operator must observe in order to limit any chance of damage. Unfortunatelly, the fact that RF Explorer is a cheaper device doesn't mean it can work without protection.

The first and most obvious precaution is to make sure the input RF power is not beyond the acceptable levels of the instrument.

RF Explorer 3G Combo and WSUB3G models are well protected up to +30dBm (1Watt) input power, which is plenty to play safe in pretty much any environment.

However, other RF Explorer models have a maximum safe input power of +5dBm, which is 3mW in the RF SMA port. As an reference, that is the power captured by the RF antenna from a cell phone a distance of 10cm, or from a Microwave oven at about 1 meter distance. Not all the ovens or cell phones work the same, so take this as an indication only.


What may not be obvious to all users is this is a limit in any RF frequency band, even if the RF Explorer is powered off.


As an example, the RF Explorer WSUB1G -with a frequency range of 240-960MHz- will not detect a microwave oven (2.4GHz) on the screen but can be very well damaged by it. Similarly, a strong 2m HAM or FM high power transmit station won’t be detected by this model, but still induces enough RF power to kill the RF circuitry with ease. And that doesn’t depend on RF Explorer being on or off because the antenna will receive that powerful signal and will inject it into the spectrum analyzer, with serious risk of damage.



In addition to RF power, you should reduce the likelihood of static discharge over the antenna. In particular, the naked metallic antennas such as the Nagoya telescopic antenna we include in the wideband models. The whip helical plastic antennas included in the narrow band models do not expose the internal contact to the outside world and thus are safer from ESD perspective because don't offer a direct current path to the internal sensitive CMOS component pin, but all metallic antennas needs you to observe good ESD practices, most importantly in very dry winter air: Make sure you have a good hand contact with the metal case of the RF Explorer before touching the antenna and, whenever possible, do not touch the antenna with your hands.


For this very same reason, you should never make contact with the antenna to any external energy source. Just imagine what power can be injected inside if you make the antenna contact to AC current or a powerful AC source of any kind!


If the RF Explorer RF circuitry is damaged, you will need to send it back for repair, taking time and cost so we strongly suggest using one or several standard procedures used for decades by RF technicians to protect your instrument:

  • The ideal device to protect your RF Explorer against strong RF fields is a RF Power Limiter. There are several options in the market, but we designed a compact, multi-purpose RF Explorer Power Limiter device with a very attractive price and the addition of advanced features such as an embedded 6dB attenuator and a 16V DC block. It will protect your RF Explorer for any power up to 1W (+30dBm) - For more details on this power limiter see this article.

Other options available in the market are for instance this power limiter from Mini Circuits: ZFLM-252-1WL+, available for less than $100, but does not include extra attenuator or DC block functionality, and is significantly larger in size.

An valuable update comes from user Bob Johansen points out this interesting Mini-Circuits application note on power limiters, very useful!

  • If you do not own a power limiter, ideally if you store the RF Explorer in your lab for no use, either enclose it within a metal case to protect it from external RF fields or, if not possible or available, unplug the antenna out of the SMA connector. This will significantly decrease the chances of high RF power get into the RF circuitry. If you know there may be strong RF fields nearby, it is even safer to plug a 50ohm SMA dummy load to the RF connector so the RF circuitry doesn’t receive any external RF field. You can find 50 ohm dummy loads in SeeedStudio for only $8.

  • When operating your instrument in unknown area where strong RF fields may be nearby, never plug the antenna into the SMA connector directly, always use a 30dB SMA attenuator to reduce the potential power received. This will increase the max power you can receive, but will reduce sensitivity as well. Remember this is required even if the instrument is not powered on yet. You can find SMA attenuators in SeeedStudio for convenient 60dB, 30dB and 10dB attenuation values.

    High Frequency Precision 30dB Attenuator High Frequency Precision 10dB Attenuator High Frequency Precision 60dB Attenuator

  • If the RF power comes from an out-of-band source, but you still want the maximum in-band sensitivity, a SMA attenuator may not be the best option because it reduces sensitivity in all bands. For instance, if you are using the WSUB1G model to monitor a weak 433MHz signal and know there is a strong 1.2GHz source nearby, the attenuator may not be the best option because it will attenuate the 1.2GHz signal but also the 433MHz signal. So in this case a good RF band pass filter may be the best option. There are many different options for filters, not all of them cheap, so look for available options for your band before taking this path. The Mini-Circuits website may be a good place to start.


Let us know if you have any question, we take client satisfaction seriously and want to make sure you enjoy your device for years without issues.

If your unit needs repair because the RF circuitry went unresponsive, let us know, we will find the best and most efficient way to offer a cost sensitive repair service.


RF Explorer file formats

The RF Explorer Windows PC Client currently support the following file formats:

  • RFE data file : These files have .rfe extension and store precision Spectrum Analyzer data in a proprietary format. You can save and load these files with the Windows PC client. These files are relatively compact files that can be easily zipped and sent over email to anybody you want your data to be shared with. Given the fact that RF Explorer Windows PC Client is a free download, you can actually use these shared files with everybody even if they don't own a RF Explorer device. The File -> Save On Close menu option will save all your activity in a .rfe everytime you close the application.
  • CSV data file : These files have .csv extension and contains essentially the same data than RFE data files but in a text comma delimited format. Most applications such as Excel will reuse this file as-is, but you can also manipulate it with Perl, Phyton or any other language of your choice to aggregate, filter, recalculate, display anyway you need.
  • Starting with Windows Client version 1.09.04 (released Oct/2012) there are two CSV file options that can be used to export data:
    • Export Single Signal CSV: This is a file with a pair of [frequency (MHZ), amplitude (dBm)] per line, with a single representation of what was on screen at the time the file was exported. This is the format most Frequency Coordination third party applications will accept natively. As this represents exactly what is on screen, you should choose the mode (realtime, average, etc) you want to be used. The export tool will refuse to export the file if more than one calculator mode is selected.
    • Export Cumulative CSV: This is a complex, rich CSV file where all the captured data is exported, including all previous captured signals since the frequency or span was set in the analyzer. The file is the same format available in earlier Windows Client versions, and stores multiple lines, with all the amplitude values recorded (realtime) for every sweep point. To calculate which frequency is associated with every amplitude value, you use start frequency and step frequency as shown in the CSV header file.
      • Starting at version 1.11 (released July 2013) the cumulative CSV file includes timestamp of each sweep captured data, this allow to merge this data with GPS or other time-related events.
    • You can also select the delimiter from a set of available standard values in the configuration tab. By default it will be comma (,) but you can also use tabulator, blank, etc. Select the delimiter you want before exporting the file.

  • PNG bitmap file : These are compatible PNG files you can display and open in pretty much any modern tool. They can be saved from two different places:
    • Menu File -> Save Remote Image As... is available in the Remote Screen tab only and is the option you should use to store an exact screenshot of the RF Explorer device screen.
    • Right click on the Spectrum Analyzer main window tab to get access to Save Image As... option to store an exact screenshot of the Spectrum Analyzer data screen.
  • RFS screen file : These files have .rfs extension and store RF Explorer screenshot data in a proprietary format. It is great to store all the remote screens captured in a single file. You can access these file save/load options from the menu File -> Save RFS Screen File As... and File -> Load RFS Screen File... when you have the Remote Screen tab active.

If you are a developer and you need access to the format of any of the proprietary data files, please take a look at the open source code. Different versions of the tool may change the internal format anytime.

Troubleshooting CSV file format imports in a 3rd party application

RF Explorer for Windows is 100% compatible with selected regional settings in your computer, and will use these settings to export CSV file. This include decimal symbol, thousands separator, etc.

Unfortunately, some 3rd party applications assume specific CSV file format using predefined hardcoded field separator and decimal separator that are not defined by or compatible with the regional settings. For instance, some applications will expect the dot (.) as the only valid decimal separator and will not be able to load it if it is a comma (,) as in many countries regional settings.

If you experience problems importing CSV file formats into a 3rd party tool, contact the 3rd party vendor to understand the CSV file formats that are acceptable.

To resolve CSV format problem, try one of these workarounds:

  • If the 3rd party software is compatible with TAB delimited CSV, change the setting in RF Explorer for Windows in the Configuration tab, “CSV field separator” option to TAB.
  • In the Microsoft Windows Control Panel, change your regional settings “decimal symbol” to (.) dot. This is regardless the specific country or area you have your default configuration. Some country settings (such us U.S.) define this by default, but some other countries (such as France) define it as a comma. You can keep your default country settings but make sure to change the decimal symbol to something compatible with your 3rd party software tool.


User manual: RF Explorer for Windows PC Client

RF Explorer can be optionally connected to a Windows PC USB port for additional functionality using the RF Explorer for Windows PC Client tool.

You can download the software for free and try-before-buy any RF Explorer device. You can even download the full open source code and modify it for your needs!

Latest details on recent versions may not be detailed here yet, so it is always a good idea to check the RF Explorer Windows Client Release Notes to get the most out of your application.

Note: In addition to Windows, there is a GUI client iRF-Explorer available for Mac OSX, developed and offered for free by independent developer Dirk-Willem van Gulik visit AppStore for additional info on connecting RF Explorer with a Mac. We do not offer direct support for the Mac iRF-Explorer tool, please post your questions on the group for any question.

Note: You should use a high quality USB cable to limit the EMC interference that otherwise a PC would add to your measurements. A high quality cable comes with ferrite beads, it is shielded and more robust than a low price cable but makes a difference when you use it for an instrument like RF Explorer. Good quality connectors used in these cables also extend the life of your device if you connect it frequently.

Silabs CP210x drivers must be installed in your Windows computer for RF Explorer for Windows to connect to the device. Standard Microsoft Windows 7 and newer include this by default. For any issues related to USB drivers, please check this article online: USB drivers


Download the software from the download page. All you need is there:

Microsoft .NET 4.0 Framework libraries will be automatically installed if not already available in your system.

If you don't have the USB drivers for Silicon Labs download and install them from the same page. RF Explorer uses an embedded CP2102 USB device internally to connect with the PC. If you run into connectivity problems with USB, please check the USB Troubleshooting article.

Download and upgrade the firmware of your RF Explorer device to the latest version available, it may be required for certain functions of the PC Client to work.

There are some brief instructions and documentation in the Readme.txt as well as examples and test files in the package and program file folder after the installation.


Spectrum Analyzer main screen

The main screen includes all the functionality to make Spectrum Analyzer measurements in your PC.

Click on the image to get a high resolution view

The software will connect with RF Explorer device automatically if it is available. Otherwise, connect your RF Explorer and click on the [*] button to refresh the available USB COM ports.

You should use the high speed 500,000bps mode. If you are using a USB 1.1 old PC or have any problem, try the low speed 2400bps but that will take much longer to refresh your PC and the Spectrum Analyzer refresh rate will downscale significantly. Note you need to change the RF Explorer to 2400bps as well in the CONFIG MENU for the low speed mode to work. Both RF Explorer and the PC must use the same connection speed.

When the connection is in place it automatically starts in RUN mode, download live data and displaying it on screen. You can stop live data anytime by clicking on HOLD button.

The Sample value will grow to show how many complete data sweeps have been captured. In RUN mode it always updates to the latest captured data set, whereas in HOLD mode you can manually go back and forth to review captured data.

Iterations value defines how many data samples will be used for the calculator in Average, Max Peak and Minimum. Realtime data is unaffected by the number of iterations. You can select which of the 4 calculator mode data representation will be displayed on screen:

  • Realtime: Raw data as captured with no post-processing
  • Average: Arithmetic media of all the last iterations sampled
  • Max Peak: Maximum value of all the last iterations sampled
  • Max Hold: Maximum value of all captured samples regardless Iterations value - this is only available from the View menu
  • Minimum: Minimum value of all the last iterations sampled

The data screen is a high speed data representation of Spectrum Analyzer Frequency vs Amplitude, same as with RF Explorer screen. However, you can do a number of advanced actions you cannot do on the smaller device screen. By right clicking on the data screen you open a context menu which offers you ways to Zoom In, Zoom Out, Print data or even export the image as a PNG bitmap file. You can also use Copy in order to have a clipboard copy of the image to be pasted in other Windows applications.

If "Show Point Values" is enabled, you can move the mouse pointer over the data graph and will display data point values one by one.

By default the screen will display the Peak value but can be disabled on the menu View->Show Peak Values option.

The current Spectrum Analyzer configuration of the RF Explorer device connected can be easily controlled from the Windows PC Client software. You can specify frequency and amplitude configuration and then click on Send for the RF Explorer to reconfigure with your new settings. To undo all the edits and go back to RF Explorer settings anytime (before you click on Send) you can use Reset to restore all last values received from the device.

Data can be saved to RFE data files or exported to CSV for use in 3rd party tools such as Excel, IAS or LabView. There is more info here.

Internal data buffer can be reset anytime to clean it from earlier captures by using Reinitialize Data Buffer option. This is done automatically anytime frequency configuration of the device is changed. The previously captured data will be persisted to RFE data file if the "Continuous log to RFE data file" option is set.

Screenshot image being displayed at anytime can be saved to a file with the "Save Bitmap screenshot image" option. The actual filename and contents will vary as a function of the currently displayed image.


Waterfall screen

This is a powerful, high performance 2D/3D visualization of historical sweeps, displaying the most recent captured sweep in front, with older sweeps in the background. It is a very efficient and practical way to display intermitent or time-changing signals that may not be easy to detect any other way.

The color map used by the Waterfall screen is defined by the Top and Bottom amplitude signals configured on the spectrum analyzer. Signal peaks that are close to the top will show red region whereas signals close to the bottom will display blue, with a color gradient in between. The "heat" of the display color code can be dinamically adjusted by changing the Top and Bottom amplitude settings anytime.

You can choose between 4 different perspectives, including a 2D view that is best suited for accurate signal research.

There are multiple options to display the Waterfall view:

  • Select the Waterfall tab screen in order to display a full screen waterfall.
  • Right click on the waterfall screen anytime to enable a context sensitive menu. Alternatively, these options are available as well at the bottom of the View menu.
  • Alternatively, the waterfall display can be enabled on the spectrum analyzer screen, select the View menu option Include Waterfall in main screen and choose bottom or horizontal layout.
  • Waterfall screenshots can be saved to an image file.

Visualization settings

The tool offers a number of configuration settings to adapt the display to your own preferences.

The Dark Color mode will enable a black background skin, closer to desktop instruments and easier to read in certain environments. In this mode, in order to save ink, the tool will disable it temporarily anytime you print but will restore automatically after print is complete.

Fill signals option will display a filled area in all signal shapes except Realtime signal.

Smooth signals option will use soft splines to join data sweep points in order to present a calculated soft curve. In some cases, the curve calculation may be misleading and you may need to disable the smoothing in order to see raw data points accurately. As the interpolation done to join data points is always a calculated "guess", you have control on which guess mode is more accurate for each measurement.


Configuration named settings

In RF Explorer for Windows there is a simple and effective way to save an unlimited number of frequency/span/amplitude combinations identified by configuration names:

  • The "Default" configuration always exist and is the latest selected set of settings, saved transparently by the application.
  • After a specific configuration is selected, it becomes part of the graph title for easy reference of measurement configuration
  • To store the current configuration with a name, simply type the descriptive name you want on the top-screen combo box, and then click on Save button. The current configuration is persisted with that name.
  • To apply the stored settings associated with a name, select the name from the combo list and then click on Load button. The frequency/span/amplitude settings will be restored and, if a RF Explorer device is connected, these values will be updated on it as well.
  • To replace an older named configuration with the current settings on screen, select the name from the combo list and then click on Save button. The previously associated settings on that name are replaced with the new ones.
  • To delete an old configuration name you no longer use, select the name from the combo list and then click on Del button.
  • All these settings are stored in a RFExplorer_Settings.xml file in the standard application data folder. You can easily copy that XML file to another computer if you want to export your settings.


Device Menu

Starting at v1.11, the Device menu includes options to select the active RF module. Left and Right SMA connectors are available menu options when a 2-port RF Explorer such as 3G Combo or ISM Combo is connected.

The red signal mark on the connector will indicate which of the two ports is enabled at any given time, for instance in the image below the left port is red and therefore the one enabled.

The Show Device RF Connections option will show or hide the model image for the connected RF Explorer device. The software includes models for all possible combinations of modules but the pictured antennas are just a guess, it will not presume a specific antenna or RF source connected as it is impossible for the software to truly know what is connected.

By enabling the Automatic LCD OFF, the connected device will stop displaying images on the LCD screen which has the advantage of some sweep refresh speed increase and certainly a reduction of the power consumption.



RF Explorer can be calibrated to get the best possible frequency accuracy, available for several models since firmware version v1.09. Please check download area to get the latest firmware for your device. This feature is not yet available for 2.4G model, but it is for all others.

Short demo video of the calibration functionality in action.


Remote Screen tab

By clicking on "Remote Screen" tab you get access to a exact copy of the RF Explorer screen. This is a wonderful feature to share info and data capture with colleagues and friends to show what you get exactly on your device.

IMPORTANT: the remote dump capture is not available if Automatic LCD OFF is active - that is, if the device has the LCD disabled, there is no possible screen to capture so this option is disabled.



To start receiving screenshots from the RF Explorer, simply check "Remote Dump active" on. You can stop it anytime.

You can also zoom in and out at different screen sizes, and navigate through all the captured images by updating the Sample counter. Starting with v1.11 there are fine options to include header descriptive text and, beyond certain large size, the LCD grid effect can be enabled or disabled before saving the bitmap.

The images can be saved as individual PNG bitmaps or as a RFS capture file. More info see below on RF Explorer file formats article.

 Additional notes

Some features still under development or not yet completed are available as separated notes. Please check below:

  • Amplitude correction data files: link
  • Limit lines and multiple markers on screen: link

Report tab

This is technical low level data report window. There is no use of it beyond diagnosis or debug, so you normally won't go there for anything useful except you need to troubleshoot a communication or error problem.

All data in this window is automatically saved to a report file, we may ask for it if we need to work with you to resolve a specific USB or COM issue in your PC.

Hacker's corner

RF Explorer is a hacker friendly device. As hackers ourselves, we do like customizing, tinkering and expanding gadgets.

We certainly designed and built RF Explorer with these factors in mind.


  • Windows PC Client source code : Developed in C# and VisualStudio 2015 Community Edition, you can fully extend and customize it for your own needs, under LGPL license. The latest source code is available in Github repository:
    • Library .NET for easy integration of Windows applications, (Linux/Mac can use it together with mono): github link
    • Library Python 3 for plug and play integration (multiplatform): github link
    • Library for Arduino in standard C++/wiring: github link
  • UART - USB protocol specification : Full documentation to interface RF Explorer with any RS232 capable software or Operating System. The limit here is the CP2102 USB driver, currently supported in Windows, Linux, WinCE, Android and MacOS by Silicon Labs. Please refer to Github Wiki.
  • RF Explorer circuit schematic : Discover the internals of RF Explorer, so you get a better idea of how it works, and how to get the greatest value from its implemented hardware and software. RF Explorer is based on a powerful Microchip PIC24FJ64GA004 16 bits MCU, together with a Silicon Labs transceivers. Circuit link here.
  • RF Explorer for Python libraries: Python is a modern, portable multi-platform programming language. We developed a full portable library so you can create your own Python applications to connect with RF Explorer devices. Visit RF Explorer for Python wiki for more details.
  • RF Explorer IoT modules: If you need a fully customizable platform, both software and hardware, you can use RF Explorer IoT modules, supported in many platforms. More details at the IoT site.
  • Raspberry Pi: The Raspberry Pi is a nice Single Board Computer running Linux which can easily control RF Explorer and automate lot of actions. By making use of the the USB RS232 protocol, it has enough power to work realtime with RF Explorer product family. Check RF Explorer for Raspberry Pi wiki to get sample Linux source code you can use as starting point. You can also use Phyton and Mono among other libraries to communicate from Linux to RF Explorer.
  • Other Linux SBC : BeagleBone Black has been also tested to work fine with RF Explorer, if you test any other SBC please let us know so community can benefit from it.

Stay tuned for any new developments...