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 gone midnight. I asked her politely to turn it down before and was told to fuck off. So as it's on digital terrestrial broadcast TV and we have a shared antenna, I looked up the channel and frequency and set up a fairly narrow band sweep across it and connected the NanoVNA to my TV feed line. She got fed up after about 5 minutes of it cutting out every couple of seconds and turned her TV off.
That's not what I bought it for but that has been my favourite use so far. I originally purchased it to test some 70cm HT antennas.
The clone thing is more controversial than it appears at first. What actually happened was more like this:
1) The original NanoVNA developer publishes the design and quits the field.
2) OwoComm redesigns it for wider coverage, making extensive changes and substantial improvements. She releases the design under the GPL.
3) Some people in China start building clones such as the SAA-2N and making useful improvements of their own. They sell these clones at ridiculously low prices, which are only slightly profitable if at all.
4) OwoComm goes nonlinear and attacks the cloners with everything she has. (Un)fortunately she doesn't have much, because the GPL contains no anti-dumping provisions and the cloners did nothing to violate the extremely liberal license she used.
5) OwoComm does the only thing that makes sense, and returns to the drawing board to create an improved design of her own. Unfortunately the newer designs are closed, due to her previous negative experience with cloners.
It's more complicated than this, in that some of the recent clones have been accused of violating the GPL by failing to release their modified sources. But OwoComm has also not reacted in the most professional manner. The clone vendor hugen, in particular, has added quite a bit of value to the product and (as far as I can tell) has behaved in good faith, but he has been at the top of OwoComm's (s)hit list since the SAA-2N's release.
Kind of a bummer, because these are all some very talented engineers who have, collectively, delivered some amazing hardware to lots of people who would otherwise have been unable to afford anything like it. It's also true that there have been a lot of complete garbage clones released, but the one I mentioned is not one of them. It's a legitimately incredible piece of hardware. Painting all of the clones with the same brush does not capture the reality of the situation.
The advice to "beware of clones" is good advice that applies to the HackRF SDR as well. Despite HackRF being open source, it doesn't mean all clones are good clones.
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 be sufficient to deter an unscrupulous reseller.
I love my NanoVNA. I used it to tune my 6 band fan dipole. That took a lot of tuning! It works fantastically, and I've made contacts from the UK to Australia with it.
I've also used it for measuring the resonance frequency of tuned circuits and even as an RF signal generator.
Every radio amateur should have one! In fact if you are into any sort of radio it is useful. I also used mine to investigate the quality of various WiFi antennas to see if they were resonant in the right places.
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 NanoVNA would feel cramped now... but still: E&M would have been so much easier to understand with one of these, and a few labs.
It’s utterly depressing watching people fish out cash for an MFJ tuner these days. They still sell the things and they still command a stupid price for a thoroughly inferior device.
The two guys I know who still own them only do so because they are Sinophobes and MFJ stuff is (terribly) assembled in the US still.
A coworker was just showing me his the other night. We pitted it against a much more expensive network analyzer to see how it did and it was quite impressive, especially considering the price and size, and was definitely serviceable for amateur and student use. It's a seriously exciting device.
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.
A Network Analyzer is an instrument to analyze the performance of a network of electronic components. Vector means that it analyzes phase as well.
It can tell you the effective Resistance, Inductance and Capacitance of the network at various frequencies. This is useful for tuning radio antennas or filters, or identifying bad cables or connectors.
You can precisely measure the length of a cable from one end (by measuring the time for the signal to reflect).
You can use it as a signal generator to illegally jam your neighbors TV signal, as another commenter here noted.
Not many common uses for it unless you think amateur radio is common.
While mastax's explanation is correct, it's not really "like you're 5."
These low end VNAs have two connectors. A signal comes out of connector 1 and goes to connector 2. What happens to that signal is measured, including the change in amplitude (up or down) and phase shift (left or right.) Also, whatever signal bounces back to connector 1 is measured for amplitude and phase.
With that you can tune antennas, characterize filters, measure attenuators and amplifiers, measure distances on transmission lines, measure resonators, capacitors and inductors and some other stuff.
That's about as simple as it can be explained without resorting to baby talk.
In 2016 a low end, non-pro 100 KHz - 4 GHz VNA cost me $430. I thought that was a game changing deal back then: being able to buy a new working VNA for under $1000. While the NanoVNA's aren't even quite the quality of even my lowend pocketVNA they do give you a qualitative picture of what's going on for $50. That's a real game changer.
It is shown in the specifications table. It looks like the Plus4 Pro has higher sweep rates (600 pts/sec) vs 200-400 on the Plus4, as well as a 10dB lower noise floor for the same amount of averaging. It seems that 6 dB comes from a tighter measurement bandwidth on the Plus4 Pro. Oddly enough, the accuracy is not stated in the spec table for any of the models. If they are the same (are they?), then it looks like you can save $100 if you can live with waiting longer to get a measurement result.
It's a shame there are not very many devices working in audio range (sub 100khz).
You still have to scout eBay for a device from the 80s-90s and they are still expensive as hell.
I was using one of these to prototype a wireless fencing system, it was a real godsend. The refresh rate wasn't good enough but it showed the concept worked good enough that I'm aiming to get a prototype together.
What the frequency range means in vector network analyzers is that the device is capable of generating a pure tone up to 4 GHz or so, and it's internal transmission lines and parts are spec'd to not be too lossy up there. A VNA generates a pure signal of a known power, puts it out the port 1 and looks how much of that power (at that freq) is reflected back by the device attached to that port (and how much makes it to port 2 (vs frequency) if it's a two port device).
It is not doing any sampling or receiving really. And concepts like instantaneous bandwidth don't matter much.
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 digitally.
hughrr|4 years ago
On to more optimistic things: these are really good. My neighbour is fairly deaf and has her television obnoxiously loud watching snooker until gone midnight. I asked her politely to turn it down before and was told to fuck off. So as it's on digital terrestrial broadcast TV and we have a shared antenna, I looked up the channel and frequency and set up a fairly narrow band sweep across it and connected the NanoVNA to my TV feed line. She got fed up after about 5 minutes of it cutting out every couple of seconds and turned her TV off.
That's not what I bought it for but that has been my favourite use so far. I originally purchased it to test some 70cm HT antennas.
CamperBob2|4 years ago
1) The original NanoVNA developer publishes the design and quits the field.
2) OwoComm redesigns it for wider coverage, making extensive changes and substantial improvements. She releases the design under the GPL.
3) Some people in China start building clones such as the SAA-2N and making useful improvements of their own. They sell these clones at ridiculously low prices, which are only slightly profitable if at all.
4) OwoComm goes nonlinear and attacks the cloners with everything she has. (Un)fortunately she doesn't have much, because the GPL contains no anti-dumping provisions and the cloners did nothing to violate the extremely liberal license she used.
5) OwoComm does the only thing that makes sense, and returns to the drawing board to create an improved design of her own. Unfortunately the newer designs are closed, due to her previous negative experience with cloners.
It's more complicated than this, in that some of the recent clones have been accused of violating the GPL by failing to release their modified sources. But OwoComm has also not reacted in the most professional manner. The clone vendor hugen, in particular, has added quite a bit of value to the product and (as far as I can tell) has behaved in good faith, but he has been at the top of OwoComm's (s)hit list since the SAA-2N's release.
Kind of a bummer, because these are all some very talented engineers who have, collectively, delivered some amazing hardware to lots of people who would otherwise have been unable to afford anything like it. It's also true that there have been a lot of complete garbage clones released, but the one I mentioned is not one of them. It's a legitimately incredible piece of hardware. Painting all of the clones with the same brush does not capture the reality of the situation.
dhdc|4 years ago
MegaDeKay|4 years ago
https://greatscottgadgets.com/2021/12-07-testing-a-hackrf-cl...
jacquesm|4 years ago
PhantomGremlin|4 years ago
The security wouldn't need to be perfect. Even something simple would be sufficient to deter an unscrupulous reseller.
nickcw|4 years ago
I've also used it for measuring the resonance frequency of tuned circuits and even as an RF signal generator.
Every radio amateur should have one! In fact if you are into any sort of radio it is useful. I also used mine to investigate the quality of various WiFi antennas to see if they were resonant in the right places.
bjt2n3904|4 years ago
Having used a modern VNA, the NanoVNA would feel cramped now... but still: E&M would have been so much easier to understand with one of these, and a few labs.
hughrr|4 years ago
The two guys I know who still own them only do so because they are Sinophobes and MFJ stuff is (terribly) assembled in the US still.
madengr|4 years ago
lxe|4 years ago
GravitasFailure|4 years ago
jmrm|4 years ago
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.
riidom|4 years ago
What is a VNA?
What are some exemplary, common things I could do with it?
mastax|4 years ago
It can tell you the effective Resistance, Inductance and Capacitance of the network at various frequencies. This is useful for tuning radio antennas or filters, or identifying bad cables or connectors.
You can precisely measure the length of a cable from one end (by measuring the time for the signal to reflect).
You can use it as a signal generator to illegally jam your neighbors TV signal, as another commenter here noted.
Not many common uses for it unless you think amateur radio is common.
topspin|4 years ago
These low end VNAs have two connectors. A signal comes out of connector 1 and goes to connector 2. What happens to that signal is measured, including the change in amplitude (up or down) and phase shift (left or right.) Also, whatever signal bounces back to connector 1 is measured for amplitude and phase.
With that you can tune antennas, characterize filters, measure attenuators and amplifiers, measure distances on transmission lines, measure resonators, capacitors and inductors and some other stuff.
That's about as simple as it can be explained without resorting to baby talk.
superkuh|4 years ago
andi999|4 years ago
MegaDeKay|4 years ago
intricatedetail|4 years ago
squarefoot|4 years ago
http://kokkinizita.linuxaudio.org/linuxaudio/
Look for Jaaa, near the end of the page.
Also interesting, although semi-unknown:
https://www.sillanumsoft.org/
unknown|4 years ago
[deleted]
mhh__|4 years ago
charcircuit|4 years ago
superkuh|4 years ago
It is not doing any sampling or receiving really. And concepts like instantaneous bandwidth don't matter much.
newhouseb|4 years ago
unknown|4 years ago
[deleted]
bfrog|4 years ago
abc12|4 years ago
[deleted]
myself248|4 years ago
superkuh|4 years ago
lxe|4 years ago