Other recommended projects

Here are some other excellent radio projects that can be a useful addition to NanoVNA.

They are separate projects from NanoVNA and you can go to the relevant websites for details.

tinySA

The tinySA are a small spectrum analyzers and signal generators with some nice capabilities:
tinySA
Screen size 2.8 inch
Spectrum Analyzer with two inputs, high quality MF/HF/VHF input for 0.1MHZ-350MHz, lesser quality UHF input for 240MHz-960MHz or
Signal Generator with two output, sine wave output for 0.1MHz - 350MHz and square wave output for 240MHz-960MHz when not used as Spectrum Analyzer.
Switchable resolution bandpass filters for both ranges between 2.6kHz and 640kHz
Color display showing max 290 scan points providing gapless covering up to the full low or high frequency range.
tinySA Ultra
Screen size 4 inch
Spectrum Analyzer for 0.1-800MHz or, with Ultra mode enabled, level calibrated up to 6GHz. Can observe signals up to 12GHz
Signal Generator with sine wave output between 0.1-800MHz or square wave or dual tone output up to 4.4GHz when not used as Spectrum Analyzer.
Switchable resolution bandpass filters from 200Hz to 850kHz
Built-in 20dB optional LNA
Color display showing max 450 scan points providing gapless covering up to the full frequency range.

Note that tinySA is not open source hardware, if you want to get a tinySA, you need to buy it from a store authorized by the developer.

LibreVNA

LibreVNA is a newly designed USB-based full 2-port vector network analyzer up to 6 GHz. It can provide up to 100dB of effective dynamics within 3GHz and has a measurement speed comparable to professional VNAs. For measurements requiring fast dual-port measurements, or those requiring high dynamic range, LibreVNA is a near replacement for professional VNAs.

LibreVNA is open source hardware, so you can try to make it yourself.
The complete production file is available here.

A simpler way is to buy the finished product already assembled.
You can buy LibreVNA at the following stores
AliExpress Zeenko Store
R&L Electronics in the United States
SHY store on Amazon
Eleshop B.V. in EU countries

LiteVNA

LiteVNA is a portable vector network analyzer (VNA) as small as the NanoVNA and capable of meeting the ultra-wide measurement range of 50 kHz to 6.3 GHz.
To minimize power consumption and size, the LiteVNA uses only one mixer, with multiple internal RF switches for S11 and S21 measurements, and IFFT calculations for TDR and DTF measurements.
Designed with the community's input in mind, the LiteVNA now brings faster scanning speeds and more scan points in addition to a wider measurement range. Combined with an easy-to-use interface consistent with the NanoVNA, the LiteVNA can now be easily used as a field test tool.
LiteVNA includes a MicroSD slot, so you can save field test data or screens to a MicroSD card at any time. With a measurement range of up to 6.3GHz, the LiteVNA is capable of meeting common amateur radio and IoT applications, as well as emerging 5GHz testing, enabling the application of the latest 5.8GHz wifi and 5.8GHz image transmission.

tinyPFA

The tinyPFA is a Phase Frequency Analyzer, it is a portable, battery operated, two input device with a 4 inch display that can measure very precise frequency and phase differences between the signals applied to both inputs. The input frequency can be any frequency between 1 MHz and 100 MHz. Typical use is to measure the differences between two 10 MHz clocks. The tinyPFA can numerically display the phase and frequency difference, show the measurement in a graph versus time, store the measurements on a SD card inserted into a SD card slot, or send the phase measurements over USB to a program such as TimeLab for further display and processing. Phase and Frequency measurement accuracy is better then 1e-12 divided by the measurement time in seconds with decimation set to 1 Be aware the maximum frequency difference that can be display depends on the measurement time (Tau) and is approximately 0.4 / (Tau in s) so for Tau is 1 s it is 0.4 Hz maximum difference.