What is the RF Explorer?

The RF Explorer is a portable, handheld RF spectrum analyzer that allows users to easily measure and visualize radio frequency (RF) signals in the environment. It covers a wide frequency range from 50 kHz up to 6 GHz (depending on the model) and provides a real-time view of the RF spectrum on its LCD display. Some key features of the RF Explorer include:

• Portable, battery-powered design for field use
• Real-time RF spectrum display with peak hold and max hold functions
• Frequency range from 50 kHz to 6 GHz (varies by model)
• Amplitude range from -115 dBm to 0 dBm
• Adjustable resolution bandwidth (RBW) from 1 kHz to 600 kHz
• Built-in signal generator for tracking generator measurements
• USB connection for control and data logging from a PC

The RF Explorer was designed as a low-cost alternative to expensive benchtop spectrum analyzers, making RF analysis accessible to students, hobbyists, engineers, and technicians. It packs many core spectrum analyzer capabilities into a compact, easy-to-use package at a fraction of the cost of traditional instruments.

How the RF Explorer Works

At its core, the RF Explorer is a superheterodyne receiver that downconverts RF signals to an intermediate frequency (IF) where they can be digitized and processed. Here is a simplified block diagram of the RF Explorer architecture:

[INSERT BLOCK DIAGRAM IMAGE]

The key components are:

1. RF Input – The RF signal to be analyzed enters the device through the SMA connector.

2. RF Attenuator – Provides switchable attenuation (0 to 35 dB in 5 dB steps) to handle high-level input signals and prevent overload.

3. Low-Pass Filter – Suppresses undesired high frequency signals and prevents aliasing in the mixer stage.

4. Mixer – Multiplies the filtered RF input with the local oscillator (LO) signal to downconvert it to the IF frequency. The LO frequency is set by the microcontroller to tune the analyzer.

5. IF Filter – A narrowband filter centered at the 64 MHz IF frequency. Its bandwidth determines the resolution bandwidth (RBW) of the spectrum analyzer.

6. IF Amplifier – Amplifies the filtered IF signal to a level suitable for digitization.

7. Detector – An RMS (root mean square) detector converts the IF signal to a DC voltage proportional to its power.

8. Analog-to-Digital Converter (ADC) – Digitizes the detected signal for processing by the microcontroller. The RF Explorer uses a 12-bit ADC.

9. Microcontroller – The “brains” of the RF Explorer. It controls the LO frequency, processes the digitized signal data, and generates the spectrum display. The firmware can be upgraded via the USB port.

10. LCD Display – Shows the real-time spectrum and measurement results on a backlit graphical LCD.

11. Keypad – Allows the user to control the RF Explorer settings and functions.

12. Signal Generator – A built-in tracking generator produces a CW signal at the center frequency for scalar network analysis and antenna/cable testing.

13. USB Interface – Enables remote control of the RF Explorer and data transfer to a PC. Open-source software is available for spectrum monitoring and logging.

14. Battery – The RF Explorer runs on a rechargeable lithium-ion battery for portable operation. It can also be powered via the USB port.

By rapidly sweeping the LO frequency, the RF Explorer tunes across its frequency range, measuring the power at each frequency point to build up the displayed spectrum. The RBW filter determines the frequency resolution, while the attenuator and IF amplifier set the amplitude range. Traces can be saved and recalled, and markers can measure frequency and amplitude values. With its wide frequency range, real-time display, and built-in signal source, the RF Explorer is a versatile tool for many RF applications.

Applications of the RF Explorer

The portability, affordability, and ease of use of the RF Explorer make it valuable for a wide range of RF tasks, such as:

Interference Hunting

RF interference can disrupt wireless communications, impacting Wi-Fi networks, cellular phones, Bluetooth devices, and more. The RF Explorer can quickly identify and locate interference sources by providing a real-time view of the RF environment. Its portability allows pinpointing interference “hot spots” and tracing signals to their origin. Directional antennas can further aid in localizing interferers.

Wireless Network Deployment

When setting up Wi-Fi networks, the RF Explorer can help optimize access point placement and channel assignments. By scanning the 2.4 GHz and 5 GHz bands, users can check for competing networks, measure signal strengths, and identify clear channels. This is especially useful in congested environments like offices, apartments, and public spaces with many Wi-Fi networks.

IoT Device Testing

The Internet of Things (IoT) relies heavily on wireless connectivity, with devices using protocols like Zigbee, Z-Wave, LoRa, and others in various frequency bands. The RF Explorer can verify the operation of IoT transmitters, check for spurious emissions, and ensure devices are not causing or receiving interference. Its wide frequency range covers most IoT bands.

Amateur Radio

RF Explorer is a popular tool among amateur radio enthusiasts. It can measure transmit signal characteristics, identify overload issues, and test filters and antennas. The built-in signal generator is handy for adjusting antenna tuners and measuring feed line losses. Hams can also use the RF Explorer to find clear frequencies on crowded bands.

EMC Pre-Compliance Testing

While not a substitute for a full EMC compliance test, the RF Explorer can provide a low-cost “pre-scan” to check for potential emissions issues before investing in more expensive testing. It can reveal unintentional radiators and harmonics that may exceed regulatory limits. Catching these problems early can save time and money in the product development cycle.

Specifications and Models

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

*DANL measured with 10 kHz RBW

All models have a sweep time of under 1 second, a frequency accuracy of ±1 ppm, and a measurement accuracy of ±3 dB. The “Combo” models include a built-in RF signal generator useful for scalar network analysis and antenna/cable testing.

Using the RF Explorer

The RF Explorer has an intuitive user interface based around its keypad and LCD display:

[INSERT KEYPAD/DISPLAY IMAGE]

Key functions include:

• Frequency/Span – Sets the center frequency and span (zoom level) of the displayed spectrum. You can enter frequencies directly or use the arrow keys to adjust.

• Amplitude – Adjusts the reference level (top of the display) and vertical scale (dB/div). The RF Explorer auto-scales by default but can be set manually for finer control.

• Markers – Places up to 3 movable markers on the spectrum to measure frequency and amplitude at specific points. Relative measurements between markers are also supported.

• Peak Search – Automatically places a marker on the highest amplitude signal within the displayed span.

• Traces – The RF Explorer can show multiple traces (live, average, max hold) and save/recall traces for reference or comparison.

• Limit Lines – Creates an amplitude threshold line that triggers an alarm when exceeded, useful for interference monitoring.

• Setup Menu – Accesses various settings such as RBW, attenuator, units (dBm/dBµV), brightness, USB mode, etc.

In addition to the standalone mode, the RF Explorer can be remotely controlled from a PC via the USB port. Free, open-source software is available for spectrum monitoring, data logging, and remote operation. Popular options include:

• RF Explorer for Windows – A full-featured GUI application for controlling the RF Explorer, displaying spectra, logging data, and more. Developed by the RF Explorer manufacturer.

• RFExplorer-Python-3 – A cross-platform Python library and set of example scripts for interfacing with the RF Explorer. Useful for automating measurements and integrating with other software.

• RFTrack – An Android app that pairs with the RF Explorer for mobile spectrum monitoring and signal mapping. Overlays spectrum data on Google Maps for easy visualization.

With its range of models, features, and software options, the RF Explorer offers a flexible, low-cost solution for portable RF analysis in many applications.

FAQ

What is the difference between the RF Explorer models?

The main differences are the frequency range, amplitude range, and battery life. The higher-end models like the 6G and 4G cover a wider frequency range up to 6 GHz and 4.4 GHz respectively, while the lower-end models focus on specific bands like the ISM (industrial, scientific, and medical) frequencies. The “Combo” models add a built-in signal generator. All models share core features like real-time spectrum display, adjustable RBW, and USB connectivity.

Can the RF Explorer be used for EMI troubleshooting?

Yes, the RF Explorer is a useful tool for identifying and locating sources of electromagnetic interference (EMI). Its real-time spectrum display and portability make it well-suited for tracking down rogue transmitters, faulty equipment, and other interference sources. However, for full EMI compliance testing, a more advanced spectrum analyzer or EMI receiver is required to meet regulatory standards.

How does the RF Explorer compare to a benchtop spectrum analyzer?

The RF Explorer offers good performance for its size and cost but does not replace a high-end benchtop spectrum analyzer. Key limitations compared to benchtop models include:

• Lower dynamic range and sensitivity
• Limited RBW options
• No advanced triggering or analysis functions
• 8-bit display with lower resolution
• Less robust RF input protection

However, for many field applications and quick checks, the RF Explorer provides sufficient performance at a much lower cost and with greater portability than a benchtop model.

What antennas can be used with the RF Explorer?

The RF Explorer has a standard SMA connector and can be used with any antenna that matches its frequency range and connector type. Common options include:

• Whip antennas for general-purpose use
• Directional antennas (Yagi, log-periodic, etc.) for point-to-point measurements and interference hunting
• Near-field probes for locating small radiators and PCB diagnostics

Using an antenna with gain can improve the sensitivity of the RF Explorer and help detect weaker signals. However, for accurate absolute amplitude measurements, the gain of the antenna must be accounted for.

Is the RF Explorer suitable for educational use?

Absolutely! The RF Explorer is an excellent tool for teaching RF concepts and spectrum analysis techniques. Its low cost and ease of use make it accessible to students, while its portability enables classroom demonstrations and field experiments. Many universities and technical schools use the RF Explorer in their wireless, IoT, and communications courses. The open-source software also allows students to develop their own applications and measurement scripts.