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NanoVNA: Low-cost handheld 4GHz vector network analyzer

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Re: NanoVNA: Low-cost handheld 4GHz vector network analyzer

#41

Post by genewitch »

newhouseb wrote: post #23
charcircuit wrote: post #16

So does it do 4 billion measurements per second, or 8 to accurately measure a 4GHz signal?

You don't need to sample at the Nyquist rate (i.e. 2x the intended measured frequency) to detect the presence of a particular signal but instead can just measure the overall power within a narrow frequency band of interest. Practically speaking this is done by mixing the sweep frequency down to at or around DC and then either directly measuring the power or sampling at a much lower rate and computing the power digita…

I don't think this is true, otherwise I could see the power on wifi bands with my 2.4ghz rtl-sdr device, instead of only up to 1200mhz.

Re: NanoVNA: Low-cost handheld 4GHz vector network analyzer

#42

Post by jmrm »

I find incredible a product like this is in the market, where the minimal price to pay for a similar professional device is around $4000, maybe a couple thousands for lower end models.

Of course the accuracy of this device might be a lot less than those professional devices, but when you are a ham amateur hobbyist who want to know if some transceiver, antenna, cables, or other devices are working good, you get a lot of "device" for such a low price.

Re: NanoVNA: Low-cost handheld 4GHz vector network analyzer

#43

Post by madengr »

bjt2n3904 wrote: post #3

Having this device in college when I was doing E&M would have been an absolute game changer. The closest thing that existed was an MFJ antenna tuner for Ham Radio that only measured S11 at one frequency, and cost around $500. The next step up was to buy used equipment, which was four figures or more. Having something that goes to 1 GHz, does both S11 and S21, and only costs $50? Unreal. Having used a modern VNA, the…

Ha ha, I had to use a slotted line.

Re: NanoVNA: Low-cost handheld 4GHz vector network analyzer

#45

Post by MertsA »

dhdc wrote: post #35
hughrr wrote: post #2

Make sure you read the "beware of clones" section carefully. There are some real shysters out there. Even the official UK reseller of the "lesser" sub 1GHz NanoVNA has been caught shipping cloned crap that doesn't even pass self test or work properly on multiple occasions. On to more optimistic things: these are really good. My neighbour is fairly deaf and has her television obnoxiously loud watching snooker until go…

Be careful, this isn't something you should talk about/admit in public at all. Feds really don't like it when people mess around licensed bands.

That's on a shared antenna so no significant broadcast going on, just interfering on the local coax. Never heard of antennas being shared between homes before like that but if it is what he says then it'd be too low power to matter outside of what's directly connected.

Re: NanoVNA: Low-cost handheld 4GHz vector network analyzer

#46

Post by GrumpyYoungMan »

PhantomGremlin wrote: post #4
hughrr wrote: post #2

Make sure you read the "beware of clones" section carefully. There are some real shysters out there. Even the official UK reseller of the "lesser" sub 1GHz NanoVNA has been caught shipping cloned crap that doesn't even pass self test or work properly on multiple occasions. On to more optimistic things: these are really good. My neighbour is fairly deaf and has her television obnoxiously loud watching snooker until go…

There's probably a market for a sub $1 "smart chip" that can be added to a design. Something that can be factory programmed with a unique serial number. To keep from being cloned, verification operation wouldn't be as simple as reading out the number. Instead, the chip would respond with some sort of hash. Similar to how Apple secures their SOCs. The security wouldn't need to be perfect. Even something simple would b…

There are inexpensive RFID tags with anti-counterfeiting features meant for retail goods, since that's become an increasing problem. They're primarily intended for retailer use since ordinary people don't have a RFID reader but since RFID readers are getting cheaper all the time, there is talk about consumers being able to authenticate their goods as well sometime in the future.

Re: NanoVNA: Low-cost handheld 4GHz vector network analyzer

#48

Post by R0b0t1 »

MertsA wrote: post #45
dhdc wrote: post #35

Earlier quoted context omitted.

Be careful, this isn't something you should talk about/admit in public at all. Feds really don't like it when people mess around licensed bands.

That's on a shared antenna so no significant broadcast going on, just interfering on the local coax. Never heard of antennas being shared between homes before like that but if it is what he says then it'd be too low power to matter outside of what's directly connected.

Interfering with her reception of broadcast TV is what is illegal. It doesn't need to impact more than one person. Cable is a different matter, you could try for civil damages but I see that as unlikely to get anywhere.

That said, being too loud is interfering with someone's life, so personally seems fair.

Re: NanoVNA: Low-cost handheld 4GHz vector network analyzer

#49

Post by R0b0t1 »

PhantomGremlin wrote: post #4
hughrr wrote: post #2

Make sure you read the "beware of clones" section carefully. There are some real shysters out there. Even the official UK reseller of the "lesser" sub 1GHz NanoVNA has been caught shipping cloned crap that doesn't even pass self test or work properly on multiple occasions. On to more optimistic things: these are really good. My neighbour is fairly deaf and has her television obnoxiously loud watching snooker until go…

There's probably a market for a sub $1 "smart chip" that can be added to a design. Something that can be factory programmed with a unique serial number. To keep from being cloned, verification operation wouldn't be as simple as reading out the number. Instead, the chip would respond with some sort of hash. Similar to how Apple secures their SOCs. The security wouldn't need to be perfect. Even something simple would b…

They have this, people just don't use them. A lot of MCUs have the functionality built in now.

Re: NanoVNA: Low-cost handheld 4GHz vector network analyzer

#50

Post by R0b0t1 »

buescher wrote: post #7
PhantomGremlin wrote: post #4

Earlier quoted context omitted.

There's probably a market for a sub $1 "smart chip" that can be added to a design. Something that can be factory programmed with a unique serial number. To keep from being cloned, verification operation wouldn't be as simple as reading out the number. Instead, the chip would respond with some sort of hash. Similar to how Apple secures their SOCs. The security wouldn't need to be perfect. Even something simple would b…

They make ‘em for secure key storage. The kind of drm scheme you’re describing, though, is not going to be too challenging for someone to subvert who’s already willing to use any of a number of methods to have firmware read off a protected chip.

It's not DRM but serial or secret registry. It allows you to voluntarily check the product you've received against a known list of vendor produced products to allow you to detect a counterfeit.

With the customer as a willing participant such things are hard to subvert.

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