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On Feb 22, 2024, at 4:01?PM, Roger Jollis <rjollis@...> wrote:

?Hi all.

I have looked for past postings for my question, but don't find a >recent< answer. So here's my situation. I have destroyed my second NanoVNA, an H4 model that I bought last July to replace my last one. This time, instead of dropping it on a concrete floor, I connected the device to my DX Commander antenna project to begin to tune it. Not realizing that the front end is susceptible to ESD damage, I didn't use an attenuator or other external protection. Apparently there was a large enough static charge in the antenna system to blow the front end of the VNA. So the S11 input is completely unresponsive and the device shows a consistent random noise readout (video attached).

While I'm tempted to buy a Rig Expert, I would miss this robust community that stands behind the NanoVNA. And I have just last week ordered a NanoVNA book from RSGB that isn't here yet. So I am once again in the market for a new H4. Since there are so many clones out there, I don't want to get burned with buying a marginal clone device. Given a choice, I would prefer to purchase on Amazon where I have a gift card credit and where I can get the device fairly quickly. But most important is to have a reliable unit. Does anybody have some recent experience with which flavor of NanoVNA to buy?

Thanks in advance.

73 de K8YX

Short vid shows the SWR function with a 50 Ohm load connected to S11. Trace: 0, Format: S11 (Refl), Stimulus: 3.0-4.5Mhz. Makes no difference when it is connected to a load. Just noise.





<NanoVNA H4 Noise.mp4>

Hi all.

I have looked for past postings for my question, but don't find a >recent< answer. So here's my situation. I have destroyed my second NanoVNA, an H4 model that I bought last July to replace my last one. This time, instead of dropping it on a concrete floor, I connected the device to my DX Commander antenna project to begin to tune it. Not realizing that the front end is susceptible to ESD damage, I didn't use an attenuator or other external protection. Apparently there was a large enough static charge in the antenna system to blow the front end of the VNA. So the S11 input is completely unresponsive and the device shows a consistent random noise readout (video attached).

While I'm tempted to buy a Rig Expert, I would miss this robust community that stands behind the NanoVNA. And I have just last week ordered a NanoVNA book from RSGB that isn't here yet. So I am once again in the market for a new H4. Since there are so many clones out there, I don't want to get burned with buying a marginal clone device. Given a choice, I would prefer to purchase on Amazon where I have a gift card credit and where I can get the device fairly quickly. But most important is to have a reliable unit. Does anybody have some recent experience with which flavor of NanoVNA to buy?

Thanks in advance.

73 de K8YX

Short vid shows the SWR function with a 50 Ohm load connected to S11. Trace: 0, Format: S11 (Refl), Stimulus: 3.0-4.5Mhz. Makes no difference when it is connected to a load. Just noise.

R&L. USA storefront, run by hams, fast shipping, and they know what you
are talking about when you contact them.



73

-Jim
NU0C

On Thu, 22 Feb 2024 13:01:32 -0800
"Roger Jollis" <rjollis@...> wrote:

Given a choice, I would prefer to purchase on Amazon where I have a gift

card credit and where I can get the device fairly quickly.