RF Explorer: A Low-Cost, Portable, RF Spectrum Analyzer

Introduction to RF Explorer

The RF Explorer is a handheld, portable spectrum analyzer that covers a wide range of radio frequencies from 15 MHz up to 2.7 GHz. It is a versatile tool for analyzing and troubleshooting RF systems, detecting interference, measuring signal strength, and more.

Unlike traditional benchtop spectrum analyzers which can cost tens of thousands of dollars, the RF Explorer is very affordable, with models starting at under $200. This makes it accessible to engineers, technicians, hobbyists, and students working on a budget.

Some key features of the RF Explorer include:

  • Frequency range from 15 MHz to 2.7 GHz (depending on model)
  • Narrow resolution bandwidth (RBW) down to 1 kHz
  • Wide dynamic range over 70 dB
  • High accuracy with 1 dB amplitude resolution
  • Fast sweep speed up to 500 MSPS
  • Rechargeable Li-Ion battery for portable use
  • PC connectivity via USB for data analysis and remote control

RF Explorer Models and Specifications

The RF Explorer is available in several different models covering various frequency ranges:

Model Frequency Range
RF Explorer 6G 15 – 2700 MHz
RF Explorer 6G Combo 15 – 2700 MHz & 4850 – 6100 MHz
RF Explorer 3G 15 – 2700 MHz
RF Explorer ISM Combo 240 – 960 MHz & 2350 – 2550 MHz
RF Explorer WSUB1G 240 – 960 MHz

All models offer similar specifications and features, with the main difference being the frequency range coverage. Here are the key specifications common to most RF Explorer models:

Specification Value
Frequency range 15 – 2700 MHz (6G model)
Amplitude range -120 to +5 dBm
Amplitude resolution 1 dB
RBW 1.6 kHz min
Sweep speed up to 500 MSPS
Accuracy < 1 dB
Input 50 ohm SMA
PC connectivity USB
Battery 3.7V 1000mAh Li-Ion
Dimensions 112 x 70 x 25 mm
Weight 185 g

Applications of RF Explorer

Wireless Networking

One of the most common applications of the RF Explorer is analyzing and troubleshooting wireless networks operating in the 2.4 GHz and 5 GHz bands used by Wi-Fi, Bluetooth, Zigbee and other standards. The RF Explorer can help identify sources of interference, detect rogue access points, measure signal strength and channel usage, etc.

For example, when setting up a new Wi-Fi router, the RF Explorer can be used to perform a site survey and find the optimal channel with the least amount of interference from neighboring networks. It can display a spectral view of the entire 2.4 GHz band, showing the signal strength and bandwidth of each Wi-Fi channel.

IoT and Embedded Systems

The RF Explorer is also a valuable tool for developing and debugging wireless IoT devices and embedded systems. Many IoT applications use sub-1 GHz frequencies like 433 MHz, 868 MHz, or 915 MHz for long-range, low-power communication. The WSUB1G model covers this entire frequency range.

When designing a new IoT device, the RF Explorer can be used to measure the output power and occupied bandwidth of the wireless transmitter, to ensure regulatory compliance. It can also check for any spurs or harmonics that may be causing interference to other devices.

During deployment, the RF Explorer can help troubleshoot issues like poor signal strength or packet loss by measuring the RSSI (received signal strength indicator) and noise floor at various points in the network.

RF Circuit Design

For engineers working on RF circuit design, the RF Explorer provides a quick way to measure and plot the frequency response of filters, amplifiers, antennas and other components. By connecting the device under test to the RF Explorer’s input, and using a tracking generator or signal source on the output, the RF Explorer can display the insertion loss or gain over a wide frequency range.

This can help with tasks like tuning filters, matching impedances, characterizing antennas, and more. The RF Explorer’s portability allows these measurements to be made in the lab or in the field, without needing access to a large benchtop analyzer.

EMC Pre-Compliance Testing

While a full EMC compliance test requires expensive equipment and a certified lab, the RF Explorer can be used for pre-compliance testing and debugging of electromagnetic interference (EMI) issues. By connecting a near-field probe or antenna to the RF Explorer, it can detect and measure the strength of electromagnetic fields emitted by a device under test.

This can help identify potential sources of EMI, such as switching power supplies, high-speed digital circuits, or poor cable shielding, early in the design process. The RF Explorer’s fast sweep speed and real-time display make it easy to correlate EMI with specific operations of the device, such as transmitting data or switching loads.

Of course, the RF Explorer is not a substitute for full compliance testing, but it can help catch issues early and reduce the number of iterations needed to pass EMC certification.

How to Use RF Explorer

Making a Basic Measurement

To make a basic measurement with the RF Explorer, power on the unit and connect an antenna to the SMA input. The LCD display will show a live spectrogram of the RF signals in the selected frequency range, with amplitude on the vertical axis and frequency on the horizontal axis.

Use the arrow buttons to adjust the center frequency and span (zoom in/out). The RF Explorer will automatically set the reference level (maximum amplitude) based on the strongest signal detected. You can also manually adjust the reference level using the Up/Down buttons.

To see more details about a specific signal, move the cursor (vertical line) to the peak of interest using the Left/Right buttons. The frequency and amplitude of the signal at the cursor position will be displayed at the bottom of the screen.

Connecting to a PC

For more advanced analysis and data logging, the RF Explorer can be connected to a PC via USB. This allows you to use the free RF Explorer for Windows software to control the device, view real-time and historical data, export data to CSV files, and more.

To connect to a PC:

  1. Install the RF Explorer for Windows software from the RF Explorer website.
  2. Connect the RF Explorer to the PC using a mini-USB cable.
  3. Launch the RF Explorer for Windows software.
  4. Select the correct COM port and click “Connect”.
  5. The software will display a live spectrogram and allow you to control the RF Explorer remotely.

Saving and Analyzing Data

The RF Explorer for Windows software allows you to log data over time and save it to a CSV file for later analysis. To start logging:

  1. Click the “File” menu and select “Log to File”.
  2. Choose a location and name for the CSV file.
  3. Select the desired logging rate and duration.
  4. Click “Start” to begin logging.

The software will save a row of data to the CSV file at the specified rate, including a timestamp, frequency, and amplitude for each data point. This can be useful for long-term monitoring or capturing intermittent events.

To analyze the logged data, you can import the CSV file into a spreadsheet or use the RF Explorer for Windows software’s built-in graphing and analysis tools. These include the ability to zoom, pan, and measure the difference between two points, as well as calculate statistical parameters like minimum, maximum, and average over a selected range.

FAQ

What is the difference between the RF Explorer and a traditional spectrum analyzer?

The main differences are size, cost, and performance. The RF Explorer is much smaller and cheaper than a benchtop spectrum analyzer, making it more portable and accessible. However, it has lower performance in terms of frequency range, sensitivity, accuracy, and resolution compared to high-end spectrum analyzers.

Can the RF Explorer be used for regulatory compliance testing?

Not for final compliance testing, which requires certified equipment and a lab. However, the RF Explorer can be useful for pre-compliance testing and debugging, to identify potential issues early in the design process and reduce the number of iterations needed to pass compliance.

What is the maximum input power for the RF Explorer?

The maximum safe input power for the RF Explorer is +5 dBm (about 3 mW). Exceeding this level can damage the sensitive receiver circuitry. When measuring strong signals, use an external attenuator to reduce the power to a safe level.

How long does the battery last?

The RF Explorer’s built-in rechargeable Li-Ion battery typically lasts for 6-8 hours of continuous use. The actual battery life will depend on factors like the screen brightness, backlight timeout, and how often data is transferred to a PC.

Can the RF Explorer be used with a Mac or Linux PC?

The official RF Explorer for Windows software only runs on Microsoft Windows. However, there are some third-party open source tools that can communicate with the RF Explorer on other platforms, such as the RFExplorer-for-Python library.

Conclusion

The RF Explorer is a powerful and affordable tool for anyone working with wireless systems, from Wi-Fi and Bluetooth to IoT and embedded devices. Its portable size, wide frequency range, and fast real-time display make it ideal for field work, while its PC connectivity and data logging enable more in-depth analysis back in the lab.

Whether you are an RF engineer, a wireless network installer, an IoT developer, or a electronics hobbyist, the RF Explorer can help you quickly analyze and troubleshoot RF issues, optimize performance, and ensure your wireless devices are operating correctly and coexisting peacefully with other systems.

Of course, the RF Explorer is not a replacement for high-end test equipment like vector network analyzers or EMC receivers. But it provides a very capable and cost-effective solution for many common RF tasks, and is a valuable addition to any wireless engineer’s toolkit.

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