Author Topic: Handheld Scope with FFT ?  (Read 2808 times)

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Offline Randy222Topic starter

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Handheld Scope with FFT ?
« on: December 01, 2023, 03:32:12 pm »
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.
 

Online Aldo22

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Re: Handheld Scope with FFT ?
« Reply #1 on: December 01, 2023, 08:13:57 pm »
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.
« Last Edit: December 02, 2023, 11:02:24 am by Aldo22 »
 
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Online Mechatrommer

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Re: Handheld Scope with FFT ?
« Reply #2 on: December 02, 2023, 04:57:57 pm »
Budget $200(US) max.
you 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.....

but I need decent FFT. I need to ID harmonics on 120vac and 240vac mains in residential and commercial space.
FFT 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 :palm:
« Last Edit: December 02, 2023, 05:04:42 pm by Mechatrommer »
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline ebastler

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Re: Handheld Scope with FFT ?
« Reply #3 on: December 02, 2023, 05:07:16 pm »
I need to ID harmonics on 120vac and 240vac mains in residential and commercial space.
Budget $200(US) max.

Would 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.
 

Online Martin72

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Re: Handheld Scope with FFT ?
« Reply #4 on: December 02, 2023, 05:58:23 pm »
FFT 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.

It 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, 14
There is nothing wrong on the screen.





« Last Edit: December 02, 2023, 06:01:43 pm by Martin72 »
 

Offline Kosmic

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Re: Handheld Scope with FFT ?
« Reply #5 on: December 02, 2023, 06:16:31 pm »

As far as I know, Owon and Hantek handhelds don't do FFT...

Owon HDS series does FFT.

https://www.owon.com.hk/products_owon_hds-n_series_2-ch_digital_oscilloscope



Used one can be relatively cheap (100$) on ebay.
 
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Online Mechatrommer

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Re: Handheld Scope with FFT ?
« Reply #6 on: December 02, 2023, 06:20:06 pm »
FFT 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.
It 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, 14
There is nothing wrong on the screen.
yes 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 is 60Hz much worse than freq i mistakenly explained and... DHO800 will be going to be a thick assed portable dso if he buy it ;D)
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline Bobson

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Re: Handheld Scope with FFT ?
« Reply #7 on: December 02, 2023, 06:38:25 pm »
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.
« Last Edit: December 02, 2023, 06:40:46 pm by Bobson »
 

Online Aldo22

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Re: Handheld Scope with FFT ?
« Reply #8 on: December 02, 2023, 06:47:03 pm »
Owon HDS series does FFT.

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.
When 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.
 

Offline Kosmic

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Re: Handheld Scope with FFT ?
« Reply #9 on: December 02, 2023, 07:38:28 pm »
Owon HDS series does FFT.

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.
When 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.

Like I said, 1ch, 20Mhz used can be found below 100$, new one below 200$.
 

Offline csuhi17

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Re: Handheld Scope with FFT ?
« Reply #10 on: December 02, 2023, 08:06:12 pm »
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
Fnirsi oscilloscope = waste&regret
 
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Online Aldo22

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Re: Handheld Scope with FFT ?
« Reply #11 on: December 02, 2023, 08:14:02 pm »
new one below 200$.

Where?
The price here is typically 389 €, on Aliexpress even more.

The Topic starter also writes "50MHz should be plenty".
 

Offline Kosmic

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Re: Handheld Scope with FFT ?
« Reply #12 on: December 02, 2023, 08:30:18 pm »
new one below 200$.

Where?
The price here is typically 389 €, on Aliexpress even more.

The Topic starter also writes "50MHz should be plenty".

just check ebay.

https://www.ebay.com/itm/263150051085 219$ (shipping included) new, open to offer.

I seen new one below 200$. But of course, they go away quickly.
« Last Edit: December 02, 2023, 08:33:22 pm by Kosmic »
 

Offline Kosmic

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Re: Handheld Scope with FFT ?
« Reply #13 on: December 02, 2023, 08:31:24 pm »
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

I have one here and I can assure you it has FFT  :)

Also the oscilloscope input is rated 400V CAT II.

Yes it's the HDS-N series, sorry.
« Last Edit: December 02, 2023, 08:39:40 pm by Kosmic »
 
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Online Aldo22

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Re: Handheld Scope with FFT ?
« Reply #14 on: December 02, 2023, 08:44:08 pm »
just check ebay.

https://www.ebay.com/itm/263150051085 219$ (shipping included) new, open to offer.

I seen new one below 200$. But of course, they go away quickly.

OK, true.
I don't know the device, but isn't it getting a bit outdated? (Oct 2009 )
 

Offline Kosmic

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Re: Handheld Scope with FFT ?
« Reply #15 on: December 02, 2023, 08:54:07 pm »
just check ebay.

https://www.ebay.com/itm/263150051085 219$ (shipping included) new, open to offer.

I seen new one below 200$. But of course, they go away quickly.

OK, true.
I don't know the device, but isn't it getting a bit outdated? (Oct 2009 )

Yes it's kind of old. Probably why the price is going down.
 
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Offline rvalente

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Re: Handheld Scope with FFT ?
« Reply #16 on: December 05, 2023, 10:47:52 am »
Used micsig
 

Offline Randy222Topic starter

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Re: Handheld Scope with FFT ?
« Reply #17 on: December 14, 2023, 03:02:47 pm »


Like I said, 1ch, 20Mhz used can be found below 100$, new one below 200$.
I 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.
 


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