How to Use a NanoVNA: The Ultimate Beginner's Guide
Welcome to the NanoVNA! Vector Network Analyzers (VNAs) used to cost tens of thousands of dollars and required a PhD to operate. Today, the NanoVNA puts that power in the palm of your hand. This guide will walk you through the user interface, basic concepts, and how to make your very first measurement.
Table of Contents
1. Understanding the Ports (CH0 & CH1)
Your NanoVNA has two SMA connectors. Understanding what they do is the first step to successful measurement:
- Port 1 (CH0 / TX): This is the Reflection port. It sends out a signal and listens to what bounces back. You use this to measure antennas, SWR, impedance, and S11 parameters.
- Port 2 (CH1 / RX): This is the Transmission port. It only listens. You use this in combination with CH0 to measure how a signal passes through a device, like a filter, amplifier, or coaxial cable (S21 parameters).
Tip: How to identify the ports
With the RF connectors facing you and the screen facing up, the left port is Port 1 (CH0) and the right port is Port 2 (CH1).
2. Navigating the User Interface
The NanoVNA can be controlled using the touchscreen or the buttons at the bottom of the device.
- Opening the Menu: Tap anywhere on the screen, or press the middle button once.
- Navigating: Tap the menu items on the screen, or press the left/right buttons to scroll and middle button to select.
- Going Back: Tap anywhere outside the menu box, or select BACK at the bottom of the menu tree.
Tip: Use PC Software!
While the standalone screen is great for field work, using the device with a PC is much easier for beginners. Check out our NanoVNA Software page to download NanoVNA-QT or NanoVNA-Saver.
3. The Golden Workflow
To get accurate results, you must follow this exact sequence every time you use the device. Memorize this 4-step process:
- Stimulus: Set your Start and Stop frequencies.
- Calibrate: Perform a SOLT calibration for the frequency range you just set. (Read the full Calibration Guide here).
- Display: Turn on the traces you want and set their formats (e.g., SWR, LogMag, Smith Chart).
- Measure: Connect your device under test (DUT) and read the results using markers.
4. Setting Traces & Formats
By default, the NanoVNA screen is cluttered with overlapping colored lines (traces). Let's learn how to control them.
Turning Traces On and Off
Navigate to . Tap TRACE 0, TRACE 1, etc., to toggle them on or off. The active trace is highlighted. It is highly recommended for beginners to turn off all traces except TRACE 0 (the yellow line).
Changing the Format
Once a trace is active, you need to tell the NanoVNA how to display the data. Navigate to and choose one of the following:
- LOGMAG: Displays signal strength in decibels (dB). Great for viewing filter passbands or return loss.
- SWR: Standing Wave Ratio. The most common format for tuning antennas. Displays as a simple ratio (e.g., 1.5:1).
- SMITH: The Smith Chart. Used by advanced users to view complex impedance (Resistance and Reactance) to design matching networks.
5. Example: Measuring Antenna SWR Step-by-Step
Let's put it all together to check a 2-meter (144 MHz) ham radio antenna.
- Set Frequency: Go to and type
140M. Go to and type150M. - Calibrate: Go to . Connect the Open, Short, and Load standards to CH0 as prompted. (See full calibration instructions).
- Clean the Screen: Go to and turn off all traces except TRACE 0.
- Set Format: Select TRACE 0, then go to and select SWR.
- Connect Antenna: Screw your antenna onto the CH0 (Port 1) connector.
- Read the Data: You will see a V-shaped dip on the screen. Go to . Use the jog wheel to move the marker to the lowest point of the dip. The frequency and SWR ratio (e.g.,
146.520MHz 1.15) will be displayed at the top of the screen!
Need Help?
If your measurements seem completely wrong, or the line is flat, you likely forgot to calibrate, or you changed the frequency range after calibrating. Always recalibrate if you change the Start/Stop frequencies!