On Thu, Nov 28, 2019 at 06:14 PM, Dejan Corovic wrote:
This guy is really going deep into NanoVNA-H, finding some problems
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Yes Owen is a knowledgeable personality but you have to remember that some of the measurements on his site are not something the NanoVNA was marketed for. The fact that he has even found the NanoVNA useable in his applications is testament to its $50 cost versus usability value. Nothing else available in that cost range comes close.
Owen only purchased the NanoVNA-H so his comments are specific to his unit. However the design faults he describes are common to all NanoVNAs and and do not only apply to the NanoVNA-H, for example his following comment:
"I identified a significant defect in my nanovna-H PCB v3.3 (says the label, but yes, it could be a fake, but a very convincing copy) that was traceable to a design failure, inadequate power supply decoupling on the three mixer chips. This was not a fake related issue, the schematic for nanovna-H PCB v3.3 shows inadequate decoupling."
The inadequate decoupling is a fairly well known issue, , but the NanoVNA meets its specifications without the decoupling and adding it will only make it perform better. Hugen, the NanoVNA-H board designer, has indicated he plans to address this and other issues in a future PCB version.
So while Owen's insights about the NanoVNA-H are in general true, they are also generally true about all NanoVNA's.
- Herb
