REVIEW - UNI-Trend UT81B Scopemeter.

[PeterG]

Hi All,
    this is my first review so please forgive anything i miss.

This meter looks great, spells great and has a great price at about $200. Does it work great? Well, look at the following pictures of the screen and you can decide that.

First lets look at its Sine Wave performance.
As you will see from these pictures, it performs very well considering it is only rated as 8Mhz bandwidth.
The Square wave however is nothing short of terrible even for this price.

Al the signals were at 5vpp from a Rigol DG1022.

[Rhythmtech]

Can you take pictures of the probe and how you have it set up?  Looks like it work fairly well for $200, not bad.

[PeterG]

I used the supplied BNC adaptor and a regular BNC-BNC lead from the FG to the meter.

[Mechatrommer]

is it possible to see current/ampere graph? i dont care even if its as small as mA or uA.

[PeterG]

shafri,
    doing a test on the Current graph wont be a problem, however, most of my gear is packed away waiting to move house. I will see what i can come up with over the next few days.

Regards

[allanw]

I think those square waves look normal for something with only 8MHz bandwidth.

[PeterG]

I am no expert in Scopes, and i am definitely not a review expert. It seems i may have been a little harsh on my assessment of this scope.

Regards

[allanw]

The 8MHz bandwidth means that it'll display a 8MHz sine wave at -3dB attenuation. From Fourier series, a square wave at frequency f is made up primarily of a sine wave at f, but also has components at 3f, 5f, etc. The higher frequency terms are what makes the transitions fast. So the 5MHz square wave actually looks pretty decent, considering the rule of thumb that you'll want 5-10 times the bandwidth of the signal you're measuring.

For something that's only $200 and portable it actually looks pretty useful.

[PeterG]

Looking at the meter and what it CAN do, i think it will do what i will ever need from a hand held scope. All i need it for is "Go/No GO" testing on cables etc. To be honest, i was thinking a square wave would be easier for a dso to capture than a sine wave. Well, i guess i did learn something today...

Regards

[Mechatrommer]

shafri,
    doing a test on the Current graph wont be a problem, however, most of my gear is packed away waiting to move house. I will see what i can come up with over the next few days.
Regards

we are at the same fate at the moment, except my stuffs are scattered around i dont have a taste to arrange properly as they will be packed anyway. so i can still access them in "panic" situation. so i'm wondering:

1) current graphing.
2) X-Y timebase, so the graph looks like sweeping from right to left (realtime) like rigol did instead of X-T timebase.

thanx.

[alm]

2) X-Y timebase, so the graph looks like sweeping from right to left (realtime) like rigol did instead of X-T timebase.

I think it only has one channel. Where would you expect the X data to come from? Regular time base is Y-T (or T-Y) by the way.

[Mechatrommer]

i found this

[Mechatrommer]

or the "special" english version
ps: i like the accent

[PeterG]

The standard package does not include a cro probe but does come with a bnc adaptor for such a probe.

Regards

[slburris]

The 8MHz bandwidth means that it'll display a 8MHz sine wave at -3dB attenuation. From Fourier series, a square wave at frequency f is made up primarily of a sine wave at f, but also has components at 3f, 5f, etc. The higher frequency terms are what makes the transitions fast. So the 5MHz square wave actually looks pretty decent, considering the rule of thumb that you'll want 5-10 times the bandwidth of the signal you're measuring.

For something that's only $200 and portable it actually looks pretty useful.

For about 2.5 times the money ($489), you can get the Hantek DS1060 which
is 60Mhz bandwidth, 150Ms/sec, with a 5.7" color screen.  It's a handheld
as well.

The Hantek meters seem to be getting good reviews over at RCgroups:

http://www.rcgroups.com/forums/showthread.php?t=1270901

Of course no review is really complete until Dave reviews it :-)

Cheapest I know of is here, anyone ever ordered from this site?

http://www.thefamousbrandsoutlet.com/test-measurement-instruments/150msa-s-handheld-scopemeter-oscilloscope-dso-1060.html

Scott

[Mechatrommer]

@slburris: i just saw the rcgroups thread, there are report indicating the unit is not performing well even at 10MHz (Hantek DS1060 is a 60MHz BW), so i wonder what will be the DS1200 (200mhZ bw) limit?

[slburris]

@slburris: i just saw the rcgroups thread, there are report indicating the unit is not performing well even at 10MHz (Hantek DS1060 is a 60MHz BW), so i wonder what will be the DS1200 (200mhZ bw) limit?

I went back and looked at the thread.  Are you referring to this comment:

As the frequency increases the generator and the scope decreases in accuracy. Above 10Mhz the mv reading getting a offset of ~0.3V That pretty darn much. The same with the generator, above 10Mhz de amplitude is getting .5V lower than the setting shows.

I think the posters later in the thread seem to like their Hantek units.  I wish there
were more reviews in general of Hantek's equipment.

Scott

[Mechatrommer]

@slburris: i just saw the rcgroups thread, there are report indicating the unit is not performing well even at 10MHz (Hantek DS1060 is a 60MHz BW), so i wonder what will be the DS1200 (200mhZ bw) limit?

I think the posters later in the thread seem to like their Hantek units.  I wish there
were more reviews in general of Hantek's equipment.
Scott

yes! that comment. i think he loved it later due to some other features. but from the accuracy point of view, that still can be questioned. i'm looking forward for a DS1200 review as if it is worthy to make a jump from DS1052E modded to this 200MHz unit.

[Fraser]

For those interested,

I have opened up my UT-81B and taken some pictures.

I attach two here for your interest.

The construction is standard Chinese OK quality but nothing amazing. It does the Job.

PCB material appears pretty good glassfibre type. Some pads are gold or nickel plated.

Obvious IC's are as follows:

ALTERA Cyclone II EP2C5T1448N
NXP LPC2138FBD64
ADG711BR
AD8651

The unit contains several Analogue Devices chips which is good to see.

LCD panel is marked Hai Nan HQTG160160A1 and is secured in place by two plastic cross straps of reasonable quality and construction.

I don't like the quality of the 4mm probe sockets but this is typical UNI-T/Chinese design and does the job OK. No idea about input protection etc. I'm affraid.

That is as far as the disassembly went as I have no wish yo break it. There are no tamper detection seals on my unit.

Regards

Fraser

[armandas]

Oooops,

Sorry for the typos in my message.... written in a hurry

Fraser

That's what the edit function is for. Enjoy

[Fraser]

Thanks 

[Mechatrommer]

great pictures Fraser!

[saturation]

These are the most vital tests, IMHO.  The edges of a square wave are composed of the highest order harmonics of the fundamental, so these represent the 5,7,9, harmonics of 1 MHz with the last 2 most represented. So, it looks like the response is good to 9 MHz, for sine waves at -3dB.

When you switched to 5 MHz, the edges show high frequency limits via a drop in the rise time.  You're now looking at distortion in the 25-45 MHz areas.  The pure sine waves shown in the OP on this thread confirms the single qualitative square wave test at 1 MHz.

A 2 MHz sq wave would be most telling.  It should show a less distorted square wave with a slow rise time; at 5 MHz, this waveform is looking more like a sine wave as the frequency response of the amp is 'filtering' off all the higher frequencies.

Hi All,
    this is my first review so please forgive anything i miss.

This meter looks great, spells great and has a great price at about $200. Does it work great? Well, look at the following pictures of the screen and you can decide that.

First lets look at its Sine Wave performance.
As you will see from these pictures, it performs very well considering it is only rated as 8Mhz bandwidth.
The Square wave however is nothing short of terrible even for this price.

Al the signals were at 5vpp from a Rigol DG1022.

[PascalS]

Just got my UT-81b. Haven't really played with it yet, but I have some new information to add to this older thread.

The package content has gotten sparser since the review.

Mine didn't have the crocodile clips which "were removed for CE compliance", which is all well and good but seriously... this is pro gear - please dear CE - I know not to use them on mains voltages... let me have some convenience with my low voltage projects <shakes head>

And the BNC-probe adapter is no longer included which is more annoying. I have a proper probe (new) for a really old analog one (I think early 70s). Will any old banana plug to BNC adapter work? Is the distance for those test lead connectors standardised across vendors?

[saturation]

Thanks for the update, please add your review and photos as you are able.

Yes, the spacing on a banana to BNC is standardized, but you can measure the UniT to confirm it.

Just got my UT-81b. Haven't really played with it yet, but I have some new information to add to this older thread.

The package content has gotten sparser since the review.

Mine didn't have the crocodile clips which "were removed for CE compliance", which is all well and good but seriously... this is pro gear - please dear CE - I know not to use them on mains voltages... let me have some convenience with my low voltage projects <shakes head>

And the BNC-probe adapter is no longer included which is more annoying. I have a proper probe (new) for a really old analog one (I think early 70s). Will any old banana plug to BNC adapter work? Is the distance for those test lead connectors standardised across vendors?