As of 2023 there are many badly performing clones on the market. V2/3GHz NanoVNA uses parts like ADF4350 and AD8342 which are costly and clones have been cutting costs by using salvaged or reject parts.
See official store and look for V2 Plus4/V2 Plus4 Pro versions only to avoid getting a bad clone. We have stopped selling V2.2 versions since October 2020, so all V2 hardware that are not Plus or Plus4 are not made by us and we can not guarantee performance.
Please note the the only official store you indicated, Tindie, is US/EU controlled, and it refuses processing orders going to Russia. These days it is quite difficult to get US/EU equipment in Russia, so it might be a good opportunity for you on the Russian market, but only if you use an adequate store. The simplest option I can think of is having an official store on AliExpress.
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