The NanoVNA V2 (aka S-A-A-2) is a vector network analyzer (VNA) with 50 kHz to 3 GHz frequency range. Recently is has become readily available for around $60 + shipping from the Tindie store. We like this product a lot and are planning to get some for our store soon as well. (Update: A limited quantity of NanoVNA V2's are now available in our store)
A Vector Network Analyzer (VNA) is an extremely useful tool for radio hobbyists as it allows you to measure and tune antennas and filters, as well as measure cable loss among other applications. Until recently low cost VNA's cost hundreds of dollars. Then came along the original NanoVNA which brought expensive VNA capabilities to the masses with its low $40 pricing. But the original design is limited to a maximum frequency of only 900 MHz. The new V2 design pushes this maximum frequency up to 3 GHz officially, and unofficially up to 4.4 GHz with reduced performance. It also improves on overall dynamic range and maintains the affordable sub $100 price. We note that the NanoVNA V2 is unrelated to the original NanoVNA apart from being the inspiration, and sharing the same firmware base.
Over on YouTube Robert J. Meade has been uploading a series of videos demonstrating and teaching viewers how to use the NanoVNA V2 to measure various devices. For example in his videos he shows how to use the NanoVNA V2 to measure one of our RTL-SDR Blog Broadcast FM filters, how to measure a log spiral & clover antenna, use measurements to rebuild a variable attenuator, measure an active device (SAWbird+ NOAA), and how to measure a DIY microstrip L-band LNA. If you're just getting started with the NanoVNA V2, then these are some great videos to start with.