nanoVNA (Vector Network Analyzer)

unofficial user guide
thanks to cho45

user guides at groups.io

VNA Basics
  Keysight
  Agilent

beginners guide video

thanks to Joe Smith

nanoVNAsharp Windows software video

thanks to IMSAI Guy

2-port measurements video

thanks to Volker Block

"official" manual


Physical attributes

Measurement range:
70dB (50kHz-300MHz), 50dB (300M-600MHz), 40dB (600M-900MHz)
Port SWR < 1.1
Frequency error < 0.5ppm
Battery 602035 3.7V 350mAh 20x35x6mm
multi-directional switch K1-1502SA
USB connectors Type C except for Micro-USB B on white gekkos.
schematic diagram
hardware versions

LEDs

One LED (between USB and power switch) blinks @ 1/2Hz while charging,
then illuminates constantly;
- remaining on for 40 seconds after disconnecting USB or powering off,
perhaps discharging capacitors?

Another LED, between power switch and multi-directional switch,
illuminates while nanoLED is powered;
- this may be vestigal from nanoVNA prototypes lackng LCD displays.

multi-directional switch

Pressing this launches menu or selects menu item;
nudging left or right migrates among menu items or moves selected marker.

nanoVNA Calibration Considerations

PDF @ groups.io thanks to Larry Goga

Calibration for 4 track nanoVNA

click for calibration steps

thanks to Alan Victor

Some notes:

A second 50 ohm termination and female-female SMA adapter are wanted for ISOLN and THRU calibration.

Supplied and used are TWO matched cables, LOADS and one SMA adapter.
Each NUMBERED step below represents your PRESS (SOFT KEY TOUCH).

Turn on the VNA and note register 0 is ON.
CONNECT MATCHED CABLES to CH0 and CH1.

  1. DISPLAY
  2. TRACE 0
  3. SINGLE
  4. TRACE 1
    Now S11 and S22 both display ONLY as LOGMAG.
  5. STIMULUS
  6. START 100KHz
  7. STOP 500MHz
  8. BACK
  9. CAL
  10. RESET
  11. CALIBRATE
    Note! No softkeys (right side of touch screen) are highlighted.
    Place an OPEN on end of CH0 cable and this will be followed by a SHORT.
  12. OPEN
  13. SHORT
    Connect 50 ohm LOADs to ends of CH0 and CH1 cables.
  14. LOAD
  15. ISOLN
    Connect cables, replacing LOADs with female-female SMA coupler.
  16. THRU
  17. DONE
    Finally save to a desired register.

That's it. Check that the open, short and 50 ohm display properly.
Note, the cables are CONNECTED to CH0 and CH1a,
and calibration reference plane is at those cables ends.
However, phase is subject to error and needs addressing in another message.

Also, with SMA coupler connecting cables to CH0 and CH1,
S21 should measure nearly 0dB.


Touchscreen Calibration

click for calibration procedure via USB from PC

thanks to Larry Rothman:

For best behavior, nanoVNA devices need touchscreen calibraton,
which requires USB connection to your PC/MAC/Terminal.

  1. install STM USB drivers, if required.
  2. connect the nanoVNA and determine which serial port has been assigned (e.g. COM5)
  3. use a serial terminal emulator such as TeraTerm to access the nanoVNA console.
  4. you may need to hit the ENTER key once or twice
    to bring up its command shell prompt.
  5. at the command prompt, enter: touchcal
  6. the nanoVNA should now display a calibration point at the upper-left corner of the display.
  7. touch that corner - a new calibration point will appear at the lower right corner of the display.
  8. touch that corner - the screen is now calibrated - BUT NOT SAVED

Now, save this touchscreen calibration:

You can verify touch calibration using the menu boxes.

NOTE: saveconfig command probably also saves calibration data

TOUCH CAL
TOUCH TEST

calibration and configuration backup

Software and Firmware

firmware mitigation for nanoVNA 300MHz, 600MHz spikes

Some nanoVNAs fail when overclocked to 300MHz by standard firmware;
nanoVNA_800aa*.dfu firmware for reflashing problematic devices.

firmware versions & installation

Software alternatives

Here are Console Commands   command instability workaround

Technical

VCO (Voltage Controlled Oscillator) harmonics

thanks to Warren Allgyer:
harminics
Unusually, nanoVNA stimulus waveform is square, rather than sinusoidal.
Above 300MHz, nanoVNA boosts Si5351 output and uses its 3rd harmonic.

thanks to hugen@outlook.com:
The Si5351 internal VCO (Voltage Controlled Oscillator) maximum
operating frequency decreases with increasing temperature.
Fully enclosed cases, raising component temperatures, may be problematic.
Si5351 specified maximum is 900MHz for a divide-by-4-frequency of 225MHz.
For 300MHz output, VCOs are overclocked to 1200MHz, which some cannot.
If significant spike artifacts are noted (> 0dB) at 300MHz or 900MHz,
then 800MHz firmware is recommended.

nanoVNA principles of operation

Somewhat as described in Michael Knitter DG5MK's YouTube video:
Hamradio 2018 FA-VA5 presentation-UK

Instead of nanoVNA's SA612 mixer (also used by EU1KY analyzer),
the FA-VA5 uses 74LVC4066 analog switches
Analog switch ICs have better linearity, dynamic range and GHz bandwidths,
but switching times > 1ns limit local oscillators to 200MHz or so..

DSP

thanks to Erik Kaashoek

SA612 ICs mix reference, Ch1 and Ch0 bridge unbalance signals
to 5kHz intermediate frequency (IF) for Analog-to-Digital-Conversion (ADC).
To measure 3 independent signals,
stereo ADC internally switches one input between reflection and transmission.

DSP then quadrature mixes 5KHz IF to DC (eliminating mirror signal),
and output is averaged, which is a very effective low pass filter,
eliminating the sum at 10kHz.   No need for other filters.

Lacking access to the famous July, 2015 QEX magazine article by DG5MK..

Other technical









































Linked from DISPLAY

In addition to selecting values to be displayed,
CHANNEL submenu selects whether signals are from CH0 (TX) or CH1 (RX).









































linked from TRACE

Up to 4 simultaneous color-coded data can be plotted.
Some firmware instead supports only 2.
OFF disables this trace; SINGLE disables all other traces...?









































linked from SCALE/DIV

defaults to 10dB/dev for some DISPLAY FORMATs; I prefer 15dB/div

linked from NUM KEYS

thanks to Mike Brown

Numerical input seems a bit flaky,
although it works better for e.g. CW frequency than position.
Touchscreen typically wants calibration.
Antenna analyser firmware has a larger font;
touchscreen [mis]calibration is more critical for other firmware..

Numeric entry displays no decimal point, but one may be implied. eg:

Rocker switch input

Touchscreen input









































linked from REFERENCE POSITION

thanks to Mike Brown:
for e.g. LOGMAG
Entering 1-8 (0001 to 0008)
places the REFERENCE line 1 to 8 grid spaces from the BOTTOM.
With default setting 7 000, changing it to 8 000 moves the trace reference
(shown by a small marker at left of screen) up one grid space, to screen TOP.

for e.g SWR 1:1
trace is below screen bottom.
Changing reference position to 180 raises trace to screen bottom









































linked from ELECTRICAL DELAY

Calibration data can be modified by electrical delay in picoseconds.
Hugen customized short and accurate calibrations kits.









































linked from MARKER

While displayed markers can in theory be manipulated by hand or stylus,
touch calibration inaccuracy typically frustrates that.
Better to use the multi-directional switch..
.. or try the touchscreen calibration procedure.

SELECT MARKER
Select (by push) any of MARKER 1 - 4.
Selecting that same marker again toggles it off.
Sliding the multi-directional switch moves a selected marker.
A selected marker can change START, STOP or CENTER of sweeps.
SPAN changes sweeps when 2 markers are active.









































link from PAUSE SWEEP

This button freezes data collection.
thanks to Gary O'Neil:

The nanoVNA must remain powered on to successfully capture data via USB.

  1. With the data you wish to 'save' and port to your workstation,
    navigate to STIMULUS > PAUSE SWEEP.
    Data at the top of the screen will freeze, confirming sweep is paused.

  2. Take care to not inadvertently alter the current state...
    either by the toggle switch or touchscreen.
    Remove the NanoVNA from the DUT,
    observe that the desired data remains on the display,
    transport it to your workstation, hotplug the device into a USB port,
    then tap on the display a couple of times.
    This appears to initiate handshaking
    and establishes a connection with the workstation.

  3. Launch the nanoVNAsharp app and connect.
    App display should match that on the nanoVNA.
  4. Use nanoVNAsharp facilities to save the data.

To be clear, data is not otherwise saved within the NanoVNA.
Once PAUSE is cancelled or the nanoVNA is power cycled,
data is flushed and replaced.