umsakazo

NanoVNA RF Learning board - RF demo kit SMA training (All MIT License, design files will be released by the end of 2027)

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Here’s an introductory VIDEO DEMO on how to use the UMSAKAZO board:

https://youtu.be/kYVsM9EE5ec

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You can now buy it at https://www.rootkit.es

Available in July 2026

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Story behind the project

The famous green "RF Demo Kit for NANOVNA" board with UFL connectors was a pain to use with students in my hardware hacking bootcamps. On top of that, you can't make many connections and disconnections without breaking something. That's why I decided to design this demonstration board with SMA connectors.

It's more robust, easier to use and solder, and allows experimenting with different components and configurations to learn about RF and NanoVNA usage.

I also incorporated the concept from the famous "NanoVNA Testboard Kit," but with a larger prototyping area to fit more components.

I built everything pretty much from scratch in my own way. I hope you like the idea.

Additionally, the board comes fully assembled with high-quality 0805 SMD components (C0G, thin film... without exceeding the target price).

Being larger with more components, including more expensive components and through-hole parts, and more soldering required, the board is naturally more expensive.

If you look for a cheap SMA alternative, check this project by IMSAI Guy, but you need transplant components from the original UFL board: https://www.youtube.com/watch?v=2W0pjMk56rA

Btw, the IMSAI Guy's board is better from the point of view of RF performance, but umsakazo is designed for learning and experimentation, not for precision measurements, so I prioritized ease of use and component accessibility over high-frequency performance.

Why umsakazo name?

umsakazo means radio in Zulu (South Africa)

Getting Started with NanoVNA and umsakazo

Learn how to use NanoVNA and some electronics from scratch with umsakazo, the NanoVNA RF Learning board (RF demo kit SMA training). This tutorial will guide you through the basics of using a NanoVNA, understanding S-parameters, and performing simple measurements with the umsakazo board.

This documentation is written for the AURSINC NanoVNA-F V2 50KHz-3GHz

Assume you have the latest firmware installed and everything configured by default, as it comes from the factory.

Reset using Tera Term or any serial terminal:

ch> clearconfig 1234
Config and all cal data cleared.
ch> saveconfig
Config saved.
ch> reset
Performing reset

Now disconnect NanoVNA from the computer and power off, then power it on again to start with a clean slate. Repeat power-off and power-on two times to ensure all settings are reset.

Your first demo: SMITH S11 - RC Series

First, press on the right side of the screen to enter the NanoVNA main menu.

Select "Stimulus" to configure the frequency range.

Select "Start/Stop" to set the frequency range for your measurements (1 MHz - 250 MHz for the RC Series demo).

After clicking OK, press the right side of the screen to access the menu again, then select "Stop" to set the stop frequency range:

Press on the right side of the screen to enter the NanoVNA menu.

Select "Back" to return to the main menu.

Select "CAL" to enter the calibration menu.

Select "Reset CAL" to clear any previous calibration data (it is important to start with a clean slate for accurate measurements).

Select "Calibrate" to start the calibration process.

Connect PORT1 to the "Open" calibration standard on the umsakazo board, then select "Open" on the NanoVNA screen to perform the open calibration step.

Next, connect PORT1 to the "Short" calibration standard on the umsakazo board, then select "Short" on the NanoVNA screen to perform the short calibration step.

Next, connect PORT1 to the "Load" calibration standard on the umsakazo board, then select "Load" on the NanoVNA screen to perform the load calibration step.

Next, connect PORT1 (left) and PORT2 (right) to the "Thru" calibration standard on the umsakazo board, then select "Thru" on the NanoVNA screen to perform the thru calibration step.

Select "Done" to complete the calibration process.

Select SAVE 0 to save your calibration.

Select "S11 SMITH" from the top-left corner of the screen to display the S11 parameter on the Smith chart. The S11 green rectangle should be selected.

Connect the RC Series demo component on the umsakazo board to PORT1, and you should see the S11 response on the Smith chart.

In an RC series circuit, the impedance changes with frequency. At low frequencies, the capacitor acts as an open circuit (right). As frequency increases, the capacitor's reactance decreases, allowing current to flow more easily, and the impedance moves toward the 50-ohm center point. Since the 50-ohm resistor remains constant (aprox) while the capacitor's reactance decreases with frequency, the impedance traces a semicircle from the open-circuit point toward the ~50-ohm point.

Note: not all time is exactly 50 ohms, as the components and PCB design introduce variations, but you should see the general behavior of the RC series circuit on the Smith chart.

Now, you can use the cursor 1 to analyze the response. Press on the 1 cursor to select it, then use stick to move it around the Smith chart and observe how the S11 parameter changes with frequency.

REMEMBER: Every time you change the frequency range, you must recalibrate your NanoVNA to obtain accurate results. Calibration compensates for losses and characteristics of your measurement system, ensuring that your results are as precise as possible within the limitations of the PCB design and components used.

Your second demo: SWR S11 - 33 ohm

Recalibrate your NanoVNA for the new frequency range: 1 MHz - 100 MHz, and perform the same calibration steps as before: Reset CAL, (Open, Short, Load, Thru) to ensure accurate measurements for the 33 ohm demo.

Select DISPLAY from the main menu to enter the display settings.

Connect PORT1 to the 33 ohm demo component on the umsakazo board, and you should see the S11 response on the screen.

Select TRACE from the display menu to configure the trace settings.

Select TRACE3 to configure the settings for the third trace.

Select FORMAT to change the display format for the trace.

Select SWR to display the Standing Wave Ratio (SWR) for the S11 parameter.

Select S11 (REFL) to display the S11 parameter for the SWR trace.

Now you should see the SWR response for the 33 ohm demo on the screen. The 1.5:1 SWR line indicates the point where the impedance is 33 ohms, which is a mismatch from the 50-ohm reference impedance. Is 1.5:1 because 33 ohms is 1.5 times less than 50 ohms (50/33 ≈ 1.5). The SWR will be higher at frequencies where the impedance mismatch is greater, and it will approach 1:1 at frequencies where the impedance is closer to 50 ohms.

Your third demo: S21 LOGMAG - Band Stop

Recalibrate your NanoVNA for the new frequency range: 1 MHz - 9 MHz, and perform the same calibration steps as before: Reset CAL, (Open, Short, Load, Thru) to ensure accurate measurements for the Band Stop demo.

Connect PORT1 to the input (left) and PORT2 to the output (right) of the Band Stop demo component on the umsakazo board, and you should see the S21 response on the screen.

Now you can view the S21 LOGMAG response for the Band Stop demo. The S21 parameter represents the transmission coefficient, and in a band stop filter, you should see a drop in the S21 magnitude at the frequencies where the filter is designed to attenuate signals. The LOGMAG format displays the magnitude of S21 in decibels (dB), making it easier to visualize the attenuation effect of the band stop filter.

Select S21 LOGMAG UP RIGHT SCREEN RECTANGLE.

Move cursor 1 to analyze the S21 response. You should see the frequency and magnitude values for the point where the cursor is located, allowing you to identify the center frequency of the band stop filter and the amount of attenuation it provides at that frequency.

Select DISPLAY from the main menu to enter the display settings again.

Select SCALE to adjust the scale settings for the S21 LOGMAG trace.

Select 2.

Now you should see the S21 LOGMAG response for the Band Stop demo with a scale of 2 dB per division, allowing you to better visualize the atten