Handheld Scope with FFT ? - Page 1
Forum section: electronics / testgear

author: Randy222
author_rank: Frequent Contributor
timestamp: December 01, 2023, 03:32:12 pm
content: Just way too many devices out there, and I just don't know what's good and what's bad.Any suggestions on a basic handheld scope, possibly DSO type but observation is key, 50MHz should be plenty, but I need decent FFT. I need to ID harmonics on 120vac and 240vac mains in residential and commercial space.Budget $200(US) max.

author: Aldo22
author_rank: Super Contributor
timestamp: December 01, 2023, 08:13:57 pm
content: Handheld, mains-proof, "decent" FFT and < $200?I don't think that exists.As far as I know, Owon and Hantek handhelds don't do FFT at all and Fnirsi DPOX and Zeeweii show something, but measuring is almost impossible. Definitely not a "decent FFT" in any case.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 02, 2023, 04:57:57 pm
content: Quote from: Randy222 on December 01, 2023, 03:32:12 pmyou either wait for some chinese company design it or... add $200 more into budget and buy DHO800, it can be made portable easily but... here's the deal breaker.....Quote from: Randy222 on December 01, 2023, 03:32:12 pmFFT on cheap (less than $10K) scope may struggle to go below 500-2KHz RBW (err..... delta-f) that means, your 120,240Hz signal will get mixed with other frequencies/harmonics and lumped into one single value, this will be very disappointing once you figured it after owning a DSO and depleted money.you may want to look into actual Spectrum Analyzer (with very low RBW) and a bunch of attenuators. cheap portable chinese SA also available. less damage loss when you screw up front end with mains level voltage, ymmv.no! SA's dont go down to DC, 10kHz lowest the most

author: ebastler
author_rank: Super Contributor
timestamp: December 02, 2023, 05:07:16 pm
content: Quote from: Randy222 on December 01, 2023, 03:32:12 pmWould a (clamp) meter which can measure THD and/or the first few harmonics do the job? Google brings up the "Peakmeter MS2055" as an example in your budget range.I have no personal experience at all with that one (or a competing product) though; maybe someone with first-hand knowledge can comment or suggest alternatives? If that type of meter is an option, changing the thread title might be advisable to attract the right expertise.

author: Martin72
author_rank: Super Contributor
timestamp: December 02, 2023, 05:58:23 pm
content: Quote from: Mechatrommer on December 02, 2023, 04:57:57 pmIt is 120, 240V...Based on a mains frequency of 60Hz, I have just simulated this with the SDG2122X and the DHO804.Once "pure", then artificially implemented harmonics (the SDG can go up to the 16th harmonic), 5, 8, 11, 14There is nothing wrong on the screen.

author: Kosmic
author_rank: Super Contributor
timestamp: December 02, 2023, 06:16:31 pm
content: Quote from: Aldo22 on December 01, 2023, 08:13:57 pmOwon HDS series does FFT.https://www.owon.com.hk/products_owon_hds-n_series_2-ch_digital_oscilloscopeUsed one can be relatively cheap (100$) on ebay.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 02, 2023, 06:20:06 pm
content: Quote from: Martin72 on December 02, 2023, 05:58:23 pmyes i thought about it few minutes ago, with DHO800, we can fine tune sample rate and number of points to get appropriate freq-range and df (RBW? ENBW?) for the job, but then OP need to know formulations, i hate to explain when not asked, its going to be long anyway.. (ps: yeah it is60Hzmuch worse than freq i mistakenly explained and... DHO800 will be going to be a thick assed portable dso if he buy it)

author: Bobson
author_rank: Regular Contributor
timestamp: December 02, 2023, 06:38:25 pm
content: Hantek portable DSO-1000B/8000B series can do FFT, however limited by 8K points (FFT, overall they have 1M points). They are equivalent to DSO 5000B series.

author: Aldo22
author_rank: Super Contributor
timestamp: December 02, 2023, 06:47:03 pm
content: Quote from: Kosmic on December 02, 2023, 06:16:31 pmQuote from: Bobson on December 02, 2023, 06:38:25 pmWhen I wrote "As far as I know, Owon and Hantek handhelds don't do FFT at all", I was referring to devices < $200 as that was a requirement of the topic starter.

author: Kosmic
author_rank: Super Contributor
timestamp: December 02, 2023, 07:38:28 pm
content: Quote from: Aldo22 on December 02, 2023, 06:47:03 pmLike I said, 1ch, 20Mhz used can be found below 100$, new one below 200$.

author: csuhi17
author_rank: Frequent Contributor
timestamp: December 02, 2023, 08:06:12 pm
content: if I see correctly, the one-channel version does not contain an FFT function.and I would also like to add that it is not HDS but HDS-N

author: Aldo22
author_rank: Super Contributor
timestamp: December 02, 2023, 08:14:02 pm
content: Quote from: Kosmic on December 02, 2023, 07:38:28 pmWhere?The price here is typically 389 €, onAliexpresseven more.The Topic starter also writes "50MHz should be plenty".

author: Kosmic
author_rank: Super Contributor
timestamp: December 02, 2023, 08:30:18 pm
content: Quote from: Aldo22 on December 02, 2023, 08:14:02 pmjust check ebay.https://www.ebay.com/itm/263150051085219$ (shipping included) new, open to offer.I seen new one below 200$. But of course, they go away quickly.

author: Kosmic
author_rank: Super Contributor
timestamp: December 02, 2023, 08:31:24 pm
content: Quote from: csuhi17 on December 02, 2023, 08:06:12 pmI have one here and I can assure you it has FFTAlso the oscilloscope input is rated 400V CAT II.Yes it's the HDS-N series, sorry.

author: Aldo22
author_rank: Super Contributor
timestamp: December 02, 2023, 08:44:08 pm
content: Quote from: Kosmic on December 02, 2023, 08:30:18 pmOK, true.I don't know the device, but isn't it getting a bit outdated? (Oct 2009 )

author: Kosmic
author_rank: Super Contributor
timestamp: December 02, 2023, 08:54:07 pm
content: Quote from: Aldo22 on December 02, 2023, 08:44:08 pmYes it's kind of old. Probably why the price is going down.

author: rvalente
author_rank: Frequent Contributor
timestamp: December 05, 2023, 10:47:52 am
content: Used micsig

author: Randy222
author_rank: Frequent Contributor
timestamp: December 14, 2023, 03:02:47 pm
content: Quote from: Kosmic on December 02, 2023, 07:38:28 pmI am wanting handheld because 1) it's battery operated, and 2) I need it for traveling around in the field, need to test for harmonics on mostly 240/120vac 60Hz circuits. The Pentair VFD drives will trip GFCI breakers, but not from overload, it's typically a case of harmonics. To know the actual harmonic frequencies and-or noise being generated helps to define what type of ferrite ring suppression should be used to kill off the noise.