6 ms·

100kHz to 6GHz 2 port USB based VNA

112 points by sleepingreset 3y ago

bramblerose 3y ago
A Vector Network Analyzer - https://en.wikipedia.org/wiki/Network_analyzer_(electrical) https://en.wikipedia.org/wiki/Network_analyzer_(electrical)
- sleepingreset 3y ago
  <3
- rkagerer 3y ago
  First paragraph of the Overview section is borked: Network analyzers are used mostly at high frequencies; operating frequencies can range from 1 Hz to 1.5 THz. Special types of network analyzers can also cover lower frequency ranges down to 1 Hz. What's the first figure supposed to be?
  - Junk_Collector 3y ago
    Most likely 10 MHz. The reference links to Keysight.com and that's more or less industry standard for compensated directional couplers which are used in the large high performance VNAs. To go lower than that they usually use a directional bridge.
ycui1986 3y ago
this VNA is super great. for $600 you get up to 8Ghz (not a typo, 8GHz can be archived in harmonic mode) usable range. with two of them you can do 4port measurement. you can also produce time domain reflectometry with it. open source hardware, firmware, fpga and pc side software.
maho 3y ago
This is insane. The project includes the hardware (GHz-capable RF-generation and measurement), firmware (FPGA) and Software (a cpp GUI). Surely that can't be all from one person?
- bayindirh 3y ago
  It's under development close to 4 years. If the person has time (or doing Ph.D. or something on the subject), this is a very viable time frame to do all of this. There are other people's work in it, but it's a one man show mainly. This is a passion project and it shows. Edit: Plus, this is the second iteration of the hardware. First iteration is at https://github.com/jankae/VNA https://github.com/jankae/VNA
- rcxdude 3y ago
  It's not that hard (not that it's easy either!). The individual parts are conceptually relatively simple, the devil is all in the details. For a generalist this is a doable, but likely very time consuming project. I've done something similar (fairly different focus in purpose and specs, but the overall shape and scope is not much off) professionally, mostly on my own.
- giantg2 3y ago
  "Surely that can't be all from one person?" It's possible. Especially if they aren't a piece of shit like me.
  - seventytwo 3y ago
    Are we the same person?
    - giantg2 3y ago
      I guess that's the existential question - is one pos really any different from anotherin a meaningful way; is any person in general?
mikewarot 3y ago
This is cool, it'll be nice to have an alterative to the NanoVNA, and it looks like you've got a bit more dynamic range, as a bonus.
- dfc 3y ago
  It's not really an alternative at 4× the cost of the NanoVNA. It's more like an upgrade.
  - mikewarot 3y ago
    It's not 4x the cost of a real NanoVNA, it's 4x the cost of a clone. I'm talking about open-sourced-ness though.
unwind 3y ago
Very impressive. One minor nit: the page is for some unfathomable reason not zoomable on mobile (Chrome on Android), making the schematics hard to read. Extra annoying when you click it and get the SVG source (which means it would zoom perfectly).
- Jazgot 3y ago
  In chrome mobile you can go to the settings > accessibility > force enable zoom.
  - unwind 3y ago
    Great tip! I realized I was actually viewing the page in the Github app, so ... still no zoom. :/
spacecadet 3y ago
Beautiful stuff!
wkjagt 3y ago
This is very cool. I’ve been looking at VNAs to start making my own antennas for my Meshtastic devices.
teleforce 3y ago
Fun facts, you can build your own VNA from scratch using open source GNU Radio toolkit with any off-the-shelf SDR platform for example using the low-cost ADALM-Pluto or you can go fully gung ho with the more capable RFSoC platform [1],[2],[3],[4]: [1] Lab notebook of experiments in GNURadio: http://www.swigerco.com/gnuradio/ http://www.swigerco.com/gnuradio/ [2] Off-the-Shelf Reconfigurable Software Define Radio Approach for Vector Network Analyzer: https://jati.apu.edu.my/files/2018/12/2018_Issue2_Paper1.pdf https://jati.apu.edu.my/files/2018/12/2018_Issue2_Paper1.pdf [3] ADALM-PLUTO: Software-Defined Radio Active Learning Module (USD230): https://www.analog.com/en/resources/evaluation-hardware-and-software/evaluation-boards-kits/adalm-pluto.html https://www.analog.com/en/resources/evaluation-hardware-and-... [4] RFSoC 4x2 Development Kit Overview (USD2K): https://news.ycombinator.com/item?id=39427825 https://news.ycombinator.com/item?id=39427825
- megous 3y ago
  > or you can go fully gung ho with the more capable RFSoC platform You can't: > The RFSOC 4x2 is currently only available to staff at accredited Universities and Research Institutes.
  - haneefmubarak 3y ago
    If you go to the Real Digital site (vendor that makes the board), they appear to also sell it commercially, albeit at the higher price of ~$4k (compared to their academic pricing of ~$2k).
- stephen_g 3y ago
  Wow, that RFSoC board is incredibly cheap - ours cost $12K or so, and we needed special approval too under defence regulations.
- jdewerd 3y ago
  VNAs are fundamentally narrow-band instruments. This: > The RFsoC 4x2 board has 4x RF ADCs (5 GSPS) and 2x RF DACs (9.85 GSPS) is like chasing after a fly with a sledgehammer. It wildly over-specs something that is almost completely useless for the task at hand (real time bandwidth, mass of hammer) while it wildly under-specs the important parts (frequency range, directivity, agility of hammer).

112 points by sleepingreset 3y ago

A Vector Network Analyzer - https://en.wikipedia.org/wiki/Network_analyzer_(electrical) https://en.wikipedia.org/wiki/Network_analyzer_(electrical)

sleepingreset 3y ago
<3
rkagerer 3y ago
First paragraph of the Overview section is borked: Network analyzers are used mostly at high frequencies; operating frequencies can range from 1 Hz to 1.5 THz. Special types of network analyzers can also cover lower frequency ranges down to 1 Hz. What's the first figure supposed to be?
- Junk_Collector 3y ago
  Most likely 10 MHz. The reference links to Keysight.com and that's more or less industry standard for compensated directional couplers which are used in the large high performance VNAs. To go lower than that they usually use a directional bridge.

ycui1986 3y ago

this VNA is super great. for $600 you get up to 8Ghz (not a typo, 8GHz can be archived in harmonic mode) usable range. with two of them you can do 4port measurement. you can also produce time domain reflectometry with it. open source hardware, firmware, fpga and pc side software.

maho 3y ago

This is insane. The project includes the hardware (GHz-capable RF-generation and measurement), firmware (FPGA) and Software (a cpp GUI). Surely that can't be all from one person?

bayindirh 3y ago
It's under development close to 4 years. If the person has time (or doing Ph.D. or something on the subject), this is a very viable time frame to do all of this. There are other people's work in it, but it's a one man show mainly. This is a passion project and it shows. Edit: Plus, this is the second iteration of the hardware. First iteration is at https://github.com/jankae/VNA https://github.com/jankae/VNA
rcxdude 3y ago
It's not that hard (not that it's easy either!). The individual parts are conceptually relatively simple, the devil is all in the details. For a generalist this is a doable, but likely very time consuming project. I've done something similar (fairly different focus in purpose and specs, but the overall shape and scope is not much off) professionally, mostly on my own.
giantg2 3y ago
"Surely that can't be all from one person?" It's possible. Especially if they aren't a piece of shit like me.
- seventytwo 3y ago
  Are we the same person?
  - giantg2 3y ago
    I guess that's the existential question - is one pos really any different from anotherin a meaningful way; is any person in general?

mikewarot 3y ago

This is cool, it'll be nice to have an alterative to the NanoVNA, and it looks like you've got a bit more dynamic range, as a bonus.

dfc 3y ago
It's not really an alternative at 4× the cost of the NanoVNA. It's more like an upgrade.
- mikewarot 3y ago
  It's not 4x the cost of a real NanoVNA, it's 4x the cost of a clone. I'm talking about open-sourced-ness though.

unwind 3y ago

Very impressive. One minor nit: the page is for some unfathomable reason not zoomable on mobile (Chrome on Android), making the schematics hard to read. Extra annoying when you click it and get the SVG source (which means it would zoom perfectly).

Jazgot 3y ago
In chrome mobile you can go to the settings > accessibility > force enable zoom.
- unwind 3y ago
  Great tip! I realized I was actually viewing the page in the Github app, so ... still no zoom. :/

spacecadet 3y ago

Beautiful stuff!

wkjagt 3y ago

This is very cool. I’ve been looking at VNAs to start making my own antennas for my Meshtastic devices.

teleforce 3y ago

Fun facts, you can build your own VNA from scratch using open source GNU Radio toolkit with any off-the-shelf SDR platform for example using the low-cost ADALM-Pluto or you can go fully gung ho with the more capable RFSoC platform [1],[2],[3],[4]: [1] Lab notebook of experiments in GNURadio: http://www.swigerco.com/gnuradio/ http://www.swigerco.com/gnuradio/ [2] Off-the-Shelf Reconfigurable Software Define Radio Approach for Vector Network Analyzer: https://jati.apu.edu.my/files/2018/12/2018_Issue2_Paper1.pdf https://jati.apu.edu.my/files/2018/12/2018_Issue2_Paper1.pdf [3] ADALM-PLUTO: Software-Defined Radio Active Learning Module (USD230): https://www.analog.com/en/resources/evaluation-hardware-and-software/evaluation-boards-kits/adalm-pluto.html https://www.analog.com/en/resources/evaluation-hardware-and-... [4] RFSoC 4x2 Development Kit Overview (USD2K): https://news.ycombinator.com/item?id=39427825 https://news.ycombinator.com/item?id=39427825

megous 3y ago
> or you can go fully gung ho with the more capable RFSoC platform You can't: > The RFSOC 4x2 is currently only available to staff at accredited Universities and Research Institutes.
- haneefmubarak 3y ago
  If you go to the Real Digital site (vendor that makes the board), they appear to also sell it commercially, albeit at the higher price of ~$4k (compared to their academic pricing of ~$2k).
stephen_g 3y ago
Wow, that RFSoC board is incredibly cheap - ours cost $12K or so, and we needed special approval too under defence regulations.
jdewerd 3y ago
VNAs are fundamentally narrow-band instruments. This: > The RFsoC 4x2 board has 4x RF ADCs (5 GSPS) and 2x RF DACs (9.85 GSPS) is like chasing after a fly with a sledgehammer. It wildly over-specs something that is almost completely useless for the task at hand (real time bandwidth, mass of hammer) while it wildly under-specs the important parts (frequency range, directivity, agility of hammer).