Serial Console

The NanoVNA-H provides a command-line interface (shell) over USB. This allows direct control of all device functions, automation, and scripting.

Connect to the Console

Connect NanoVNA-H via USB
Open terminal software:
- Windows: PuTTY, TeraTerm, or Windows Terminal
- Linux: screen, minicom, or picocom
- macOS: screen or CoolTerm
Connect to the COM port at 115200 baud
Press Enter to see the prompt

Example: Using screen (Linux/macOS)

screen /dev/ttyACM0 115200

To exit screen: Ctrl+A then K, then Y

Example: Using PuTTY (Windows)

Open PuTTY
Select “Serial” connection type
Enter COM port (e.g., COM3)
Set speed to 115200
Click “Open”

Shell Prompt

When connected, you’ll see:

ch>

This is the NanoVNA shell prompt. Type commands and press Enter.

Common Commands

Get Help

help

Lists all available commands.

Device Information

version    # Show firmware version
info       # Show device information
vbat       # Show battery voltage

Frequency Control

sweep 1000000 100000000           # Start 1MHz, stop 100MHz
sweep 1000000 100000000 201       # With 201 points
sweep start 50000                 # Set only start
sweep stop 300000000              # Set only stop
freq 145000000                    # Set CW frequency

Trace Configuration

trace 0 logmag     # Trace 0 to log magnitude
trace 1 swr        # Trace 1 to SWR
trace 2 smith      # Trace 2 to Smith chart
trace 0 scale 10   # Set scale to 10 dB/div
trace 0 refpos 7   # Set reference position

Calibration

cal open           # Capture open standard
cal short          # Capture short standard
cal load           # Capture load standard
cal thru           # Capture thru standard
cal isoln          # Capture isolation
cal done           # Calculate calibration
cal on             # Enable calibration
cal off            # Disable calibration
save 0             # Save to slot 0
recall 1           # Recall from slot 1

Markers

marker 1 on        # Enable marker 1
marker 1 100       # Set to point 100
marker 1 off       # Disable marker 1
marker on          # Enable all
marker off         # Disable all

Data Export

data 0             # Get S11 data (re im pairs)
data 1             # Get S21 data
frequencies        # Get frequency list
capture            # Capture screen (raw data)

Configuration

saveconfig         # Save current settings
clearconfig        # Reset to defaults
smooth 3           # Set smoothing level
bandwidth 1000     # Set IF bandwidth
power 0            # Set power level (0-3)

Command Syntax

Commands follow this general format:

command [argument1] [argument2] [...]

Arguments are space-separated. Numeric values can be:

Integer: 1000000
Decimal: 1.5
Scientific: 1e6, 1.5e-9
With unit suffixes in some cases

Getting Command Data

Many commands output data that can be captured:

Measurement Data

data 0
# Output: pairs of real imaginary values
# 0.123456 0.234567
# 0.345678 0.456789
# ...

Frequency Points

frequencies
# Output: frequency in Hz
# 1000000
# 2000000
# ...

Capture data for S-parameter export

frequencies > freq.txt    # Redirect to file (on PC)
data 0 > s11.txt
data 1 > s21.txt

Scripting

Send multiple commands from a script:

Python Example

import serial
import time

ser = serial.Serial('/dev/ttyACM0', 115200, timeout=1)

def send_command(cmd):
    ser.write(f'{cmd}\r\n'.encode())
    time.sleep(0.1)
    return ser.read(10000).decode()

# Configure sweep
send_command('sweep 1000000 100000000 201')

# Set traces
send_command('trace 0 logmag')
send_command('trace 1 swr')

# Get data
frequencies = send_command('frequencies')
s11_data = send_command('data 0')

ser.close()

Shell Script Example

#!/bin/bash
PORT=/dev/ttyACM0

echo "sweep 1000000 100000000" > $PORT
sleep 0.5
echo "data 0" > $PORT
cat $PORT

Pause and Resume

Control sweep operation:

pause     # Stop sweeping
resume    # Resume sweeping

Use pause before making rapid configuration changes to avoid partial sweeps.

Advanced Commands

tcxo 26000000       # Set TCXO frequency
threshold 290000000 # Set harmonic switch frequency
reset               # Soft reset device
touchcal            # Start touch calibration
transform on        # Enable time domain