[HN Gopher] NanoVNA: Low-cost handheld 4GHz vector network analyzer
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NanoVNA: Low-cost handheld 4GHz vector network analyzer
Author : trishmapow2
Score : 99 points
Date : 2022-02-12 12:20 UTC (10 hours ago)
(HTM) web link (nanorfe.com)
(TXT) w3m dump (nanorfe.com)
| [deleted]
| nickcw wrote:
| 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.
| lxe wrote:
| Also see the TinySA https://www.tinysa.org/wiki/ and DSO Nano:
| https://www.seeedstudio.com/DSO-Nano-v3.html to complete your
| mini homebrew electronics and radio lab.
| superkuh wrote:
| 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.
| jmrm wrote:
| 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.
| abc12 wrote:
| riidom wrote:
| In ELI5 terms:
|
| What is a VNA?
|
| What are some exemplary, common things I could do with it?
| topspin wrote:
| 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.
| joenathanone wrote:
| >That's about as simple as it can be explained without
| resorting to baby talk.
|
| Can't say I'm not interested in what that would sound like.
| itgoon wrote:
| who's a good wittle antenna? Dats wight! You are! You a
| good wittle antenna!
| mastax wrote:
| 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.
| riidom wrote:
| Thanks!
| hughrr wrote:
| 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.
| jacquesm wrote:
| Do you realize you just admitted to a crime?
| trhway wrote:
| as a crime it may a be a small one. As a totally lacking
| empathy a*hole who denied a hearing impacted grandma her
| favorite show he is definitely a big one though.
| jacquesm wrote:
| There's that.
| hughrr wrote:
| I try and commit at least one every day :)
| jacquesm wrote:
| Committing them is one thing, admitting to them in open
| fora is another.
| PhantomGremlin wrote:
| 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.
| R0b0t1 wrote:
| They have this, people just don't use them. A lot of MCUs
| have the functionality built in now.
| rsaxvc wrote:
| One challenge - authenticity checks need to be done end-to-
| end(where we that end may be)
|
| If you had such a chip, who would check it for authenticity?
| That check would need to be well secured, so likely not the
| ARM firmware on the nanovna itself.
|
| Possibly not nanoVNA-saver: the unscrupulous supplier might
| just include an unlabeled CDR with patched software.
| GrumpyYoungMan wrote:
| 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.
| myself248 wrote:
| https://octopart.com/atsha204a-sshda-t-
| microchip-77761819?r=...
|
| But the original would have to see it coming and put this in
| the design, AND maintain a registry of all the valid chip
| serials. No hobbyist wants that headache.
| triactual wrote:
| What if I buy one real device and clone the serial number?
| This has been solved more than a decade ago but it requires
| hardware with secure storage to maintain a private key.
| Some centralized service holds the public key and can
| verify the device by asking it to sign something with the
| private key. This is basically every cell phone, quality
| IoT device, etc. The private key is installed in the
| factory, maybe provided by a secure connection back to the
| centralized service. Hardware features lock that key in
| place preventing it from being read out without a ton of
| work (connections are literally burned open with
| overcurrent inside the IC).
|
| Since the key is unique to the device, it can easily be
| disavowed in the central database if a device does become
| compromised. Anything less than this is probably a few
| hours from being completely broken. And this scheme can be
| broken by non-state actors, especially if the private key
| storage is naively or poorly implemented. Many MCUs have
| multiple levels of readout protection and it can be easy to
| misconfigure. A single mistake in memory mapping could
| expose information on external interfaces. And then you're
| trying to do all of this in China, on the cheap. Pack a
| lunch.
| myself248 wrote:
| Did you read the datasheet or are you responding to your
| imagination?
|
| Anyway, there's a litany of similar devices to fill
| whatever requirements you wish. SIM cards, for instance,
| are available in WSON8 MFF2 chips that you can directly
| solder to a board.
| triactual wrote:
| Why are you so rude? I am a hardware engineer and I'm
| explaining how you establish trust with hardware devices.
| This information isn't contained in a single data sheet,
| it spans an entire global supply chain.
|
| A SIM card is just one way to do exactly what I
| described. It's expensive and probable not a good choice
| for small, cheap devices. Not to mention brings along a
| whole host of associated security complexity.
| andi999 wrote:
| 1$ in component price is like 4$ in device sales price. It
| needs more to be in the 5 cents range.
| buescher wrote:
| 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.
| R0b0t1 wrote:
| 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.
| genmud wrote:
| There are a bunch of options out there for doing this. Many
| ICs have built in key storage, but there are a few that are
| separate. There are some pros to using on micro key
| management, but one of the big cons is that many times the
| auth can be bypassed if you can overwrite or glitch the
| firmware.
|
| If I were concerned about counterfeit things, in an
| application like this, you would pre program each one with a
| unique key and everything would be tied to it. Firmware
| upgrades need to be validated, to download, you would need
| the key, run the software, key needs to sign something
| back... etc.
|
| https://www.microchip.com/en-us/product/ATSHA204A
| dhdc wrote:
| 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.
| MertsA wrote:
| 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.
| R0b0t1 wrote:
| 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.
| hughrr wrote:
| We have Ofcom here. I have dealt with them before on behalf
| of someone else.
|
| They didn't even do anything to someone we located and
| identified and collected evidence for who was jamming amateur
| radio repeaters.
| MegaDeKay wrote:
| 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.
|
| https://greatscottgadgets.com/2021/12-07-testing-a-hackrf-cl...
| CamperBob2 wrote:
| 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.
| intricatedetail wrote:
| 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.
| squarefoot wrote:
| Many people use quality audio cards plus software to do this.
|
| http://kokkinizita.linuxaudio.org/linuxaudio/
|
| Look for Jaaa, near the end of the page.
|
| Also interesting, although semi-unknown:
|
| https://www.sillanumsoft.org/
| [deleted]
| buescher wrote:
| Dynamic analyzers are really cool. I'd like one. Too bad they
| go for silly prices.
|
| Yeah, the niche seems to be filled by software and either
| sound cards or equivalent USB acquisition hardware.
| GravitasFailure wrote:
| 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.
| bjt2n3904 wrote:
| 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.
| madengr wrote:
| Ha ha, I had to use a slotted line.
| hughrr wrote:
| 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.
| jes wrote:
| Indeed.
|
| MFJ in the amateur radio community is called "Mighty Fine
| Junk" fairly often. I have purchased some things from MFJ,
| but I notice that I now avoid doing so unless I'm desperate.
| bdavis__ wrote:
| no one confuses gear from MFJ with "high quality". cheap
| stuff, that whets your appetite for the good stuff.
|
| and yes, i have an MFJ tuner and the 20 meter QRP rig they
| sell. it is a ford or a chevy, not a lexus or a mercedes.
| (both items were received with parts loose and had to have
| some re-assembly).
| charcircuit wrote:
| So does it do 4 billion measurements per second, or 8 to
| accurately measure a 4GHz signal?
| [deleted]
| newhouseb wrote:
| 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.
| genewitch wrote:
| 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.
| CamperBob2 wrote:
| If you remove the front-end RF filter from your SDR, you
| can indeed pick up 2.4 GHz with it using harmonics of the
| ADC clock frequency. But the rest of the signal processing
| pipeline may be too narrow to receive much energy from a
| broadband WiFi signal, and what you do receive will
| probably just look like noise in any event.
|
| You could probably observe the leakage from a nearby
| microwave oven without much difficulty, though -- in fact,
| that is likely to be possible even without modifying the RF
| filter.
|
| Basically, Nyquist applies to the modulation bandwidth, not
| the carrier frequency.
| stagger87 wrote:
| Who you're responding to is correct.
| superkuh wrote:
| 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.
| myself248 wrote:
| So what's the deal with the name "NanoVNA" being applied to like
| a dozen unrelated projects now?
| lxe wrote:
| The vector analyzer is the only one I know of...
| superkuh wrote:
| It's become a well known generic name like rtl-sdr or kleenex.
| It basically just means "low end hacky VNA" now. But yeah,
| confusing.
| andi999 wrote:
| Whats the difference between the pro and normal version (apart fr
| 100$}.
| MegaDeKay wrote:
| 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.
| andi999 wrote:
| Thanks, didnt find that on mobile.
| mhh__ wrote:
| 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.
| bfrog wrote:
| I ended up buying a xaxavna which work similarly but seems to
| have better measurements
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