Buy a Vector Network Analyzer for low frequency - Page 1
Forum section: electronics / testgear

author: LazySpot
author_rank: Newbie
timestamp: October 31, 2022, 10:13:57 am
content: HiI want buy a Vector Network Analyzer, but for lower frequcy-measurement bandwidth from several dozen kHz, up to a single MHz is enough-measurement with a signal from about -45dBm-shifted measuring range - the phenomena have - in relation to the background - dynamics of the order of a few to a dozen dB-high measurement resolution of 100, 30, preferably even 10Hz-external measurement control, (step selection of frequency subbands), preferably from PC tables-preferably with an included external measuring bridgeVNA with this parameters are expensive because have a high frequency bandwidth, but I don't need it.

author: precaud
author_rank: Frequent Contributor
timestamp: October 31, 2022, 12:13:20 pm
content: Low-frequency VNA's often go by the name FRA, or Frequency Response Analyser.

author: nctnico
author_rank: Super Contributor
timestamp: October 31, 2022, 12:54:07 pm
content: The Anritsu MS4630B comes to mind. This has been discontinued so you have to buy it used. You'll need to use an external bridge but then again, at low frequencies you are likely better off using different measurement methods.I don't know of any more modern pieces of test equipment that offer similar features (no, oscilloscope FRA is not a substitute for a proper network analyser). Maybe the Analog Discovery 2 could come close to a real VNA but I have not hands on experience with that.

author: Kean
author_rank: Unknown
timestamp: October 31, 2022, 01:08:42 pm
content: Omicron Lab Bode100 - but you might not want to look at the price...https://www.omicron-lab.com/products/vector-network-analysis/bode-100/There is more discussion elsewhere here about alternatives, such ashttps://www.eevblog.com/forum/metrology/please-suggest-alternative-for-bode100/

author: egonotto
author_rank: Super Contributor
timestamp: November 01, 2022, 04:17:07 pm
content: Quote from: LazySpot on October 31, 2022, 10:13:57 amHello,then the AD2 is not suitable, unless you can use a attenuator and preamplifiers.Best Regardsegonotto

author: JohnPi
author_rank: Regular Contributor
timestamp: November 03, 2022, 04:59:10 am
content: https://github.com/jp3141/Vector-Network-Analyzermight be useful

author: Someone
author_rank: Super Contributor
timestamp: November 03, 2022, 05:51:10 am
content: Quote from: JohnPi on November 03, 2022, 04:59:10 amYes, unless speed of measurement is critical automating a scope + signal generator is usually a good choice.

author: Pitrsek
author_rank: Regular Contributor
timestamp: November 03, 2022, 10:30:34 am
content: If it's for business, Bode 100 is IMHO well worth it. If you do not need separate generator output, checkhttps://www.sdr-kits.net/introducing-DG8SAQ-VNWA3

author: RoGeorge
author_rank: Super Contributor
timestamp: November 03, 2022, 11:08:19 am
content: Quote from: JohnPi on November 03, 2022, 04:59:10 amWow, searched a few times before to find a similar VNA tool for DS1054Z and generator but couldn't find any, so I was planning to wrote my own. Thanks to your VNA on github it would be much easier now to modify that for LXI with Rigol DS1054Z scope and DG4102 AWG.Thanks a lot!

author: Evan.Cornell
author_rank: Regular Contributor
timestamp: January 19, 2023, 06:35:00 pm
content: Quote from: JohnPi on November 03, 2022, 04:59:10 amThat is very interesting. Does anyone happen to know what it would take to adapt this to work with a Tektronix MDO3014, which has built-in function generator?

author: alm
author_rank: Super Contributor
timestamp: January 19, 2023, 06:58:19 pm
content: Quote from: Evan.Cornell on January 19, 2023, 06:35:00 pmIt would take comparing the programming manuals for the two instruments and making some minor changes to the commands that are being sent. The script is just sending raw SCPI commands (or other commands for the SDG), so you will have to change the commands to what the MDO is expecting. The scope will probably be fairly similar, but the signal generator will probably be quite different.What I'd do is change it to usepython-ivi, which allows you to more easily switch between instruments. But that would definitely be a bigger project involving changes in both this script and in python-ivi.

author: jasonRF
author_rank: Regular Contributor
timestamp: January 21, 2023, 03:57:24 pm
content: Quote from: egonotto on November 01, 2022, 04:17:07 pmThe AD2 is not the only scope/generator that would have that problem. Since the OP only needs to go to 1MHz, a relatively simple op-amp based preamp would work fine. An example using a couple of TLE2072 is in the homemade instrument threadhttps://www.eevblog.com/forum/testgear/show-the-homemade-equipment-you-are-using-now/msg4500562/#msg4500562Signal generator attenuators would be even easier to build, I would think. Or just use the bnc attenuators you can buy from the usual places.jason

author: 2N3055
author_rank: Super Contributor
timestamp: January 21, 2023, 04:36:15 pm
content: Quote from: jasonRF on January 21, 2023, 03:57:24 pmThere are many scopes that have 500uV/div sensitivity up to 10V/div...They would have no problems with 3mV P-P in Bode plot...As opposed to AD2 having 2 ranges 0.5V/vid and 5V/div

author: joeqsmith
author_rank: Super Contributor
timestamp: January 21, 2023, 05:21:01 pm
content: The fact it's a VNA you require, post some details about which S parameters, power range, sweep types, features... You mention costs but don't provide a range.Not much to go on. Then again, do your homework and maybe post which ones you have looked at and where they fell short.