New oscilloscope from Fnirsi DPOS350P

[picburner]

Need to 3D print desktop stand for it.

Unless you want a special one, it already has its own.

[Ivont]

The board looks good.  Here it is. I wanted to show something but it won't upload.  Apparently they can't upload more than two photos.

[BillyO]

? 

[Ivont]

If you can tell me what to do to get this miracle back.  Analysis of filters is useless.  He doesn't stop changing and shows what he wants.  I decided they should refund some of my money.  I bought it from their official AliExpress seller.

[mishail71]

I returned mine and crossed myself!!! While this is the attitude of the manufacturer (tech support), all their products are a waste of money for me. And a waste of nerves.

[PA2ER]

I'm curious, has anyone connected the oscilloscope's generator to a frequency counter?
In my case, and that of two friends, we have the following deviations:

@10 kHz +1.919 Hz
@50 kHz +9.603 Hz
@10 MHz +1.919 kHz
@50 MHz +9.603 kHz

This was measured with a Racal-Dana 1998, with external reference.
I've already sent an email to FNIRSI to ask if this is normal, but haven't received a response yet.

[BillyO]

If you can tell me what to do to get this miracle back.  Analysis of filters is useless.  He doesn't stop changing and shows what he wants.  I decided they should refund some of my money.  I bought it from their official AliExpress seller.

Return it.

[BillyO]

I'm curious, has anyone connected the oscilloscope's generator to a frequency counter?
In my case, and that of two friends, we have the following deviations:

@10 kHz +1.919 Hz
@50 kHz +9.603 Hz
@10 MHz +1.919 kHz
@50 MHz +9.603 kHz

This was measured with a Racal-Dana 1998, with external reference.
I've already sent an email to FNIRSI to ask if this is normal, but haven't received a response yet.

Mine's the same:

10kHz = 10.002kHz
50kHz = 50.010kHz
1MHz = 1.0002MHz
5MHz = 5.0010MHz
10MHz = 10.002MHz
50MHz = 50.010MHz

HP 5302A with GPSDO ref.

So that's 0.02 % off.  They don't provide a specification, but 0.02% seems to be fine for this unit.

[Aldo22]

So that's 0.02 % off.  They don't provide a specification, but 0.02% seems to be fine for this unit.

Why fine?
The AWG of the $150 Hantek can do better.
External measurement with the FY3224s.

[Grandchuck]

Mine is about the same.  Opportunity for a tweak

[BillyO]

Why fine?
The AWG of the $150 Hantek can do better.
External measurement with the FY3224s.

My statement is based on my use cases.  If I need a precise frequency, I have much better devices for that.  With the little FNIRSI scope, all I use the generator for is to inject a signal for tracing or to see what is happening to the signal as it goes through a circuit (clipping, gross distortion, attenuation, amplification, loss, etc...).  Extreme frequency accuracy is immaterial in those cases.  I last used it to fix an audio amplifier.

Do you often need better that 0.02% yourself?

[Aldo22]

Do you often need better that 0.02% yourself?

That doesn't matter.
An accurate device is preferable to an inaccurate one, especially if it is cheaper.
Above all, however, it shows that it is possible to deliver something better in this price range.

[BillyO]

That doesn't matter.
An accurate device is preferable to an inaccurate one, especially if it is cheaper.
Above all, however, it shows that it is possible to deliver something better in this price range.

I wholeheartedly disagree.  If accuracy is not a concern, then accuracy is not as concern.  Plain and simple.  The rest is just bench racing and bragging rights.

My main generators and counters are all run off a $140 GPSDO which is accurate to a few parts per trillion (10^-10 or better).  I win.

[Aldo22]

I wholeheartedly disagree.  If accuracy is not a concern, then accuracy is not as concern.  Plain and simple.  The rest is just bench racing and bragging rights.

My main generators and counters are all run off a $140 GPSDO which is accurate to a few parts per trillion (10^-10 or better).  I win.

Non? Si! Oh! 
Do you understand French?

[BillyO]

I wholeheartedly disagree.  If accuracy is not a concern, then accuracy is not as concern.  Plain and simple.  The rest is just bench racing and bragging rights.

My main generators and counters are all run off a $140 GPSDO which is accurate to a few parts per trillion (10^-10 or better).  I win.

Non? Si! Oh! 
Do you understand French?

Une petit peu.

Très drôle ! 

[PA2ER]

Of course, it can't be compared to high-precision equipment, but let's be honest, 2 kHz off at 10 MHz isn't even useful for quick field diagnosis.

[BillyO]

Can you give me an example of where it would be useless?

Besides, if you know it's off by a consistent amount, you can allow for that.  And it does seem to be very consistent across at least our 2 machines and possibly Grandchuck's too.

A simple 0.02% correction and now you have better than 10ppm.

[Sorama]

Une petit peu.

Une un petit peu!

[PA2ER]

Can you give me an example of where it would be useless?

Besides, if you know it's off by a consistent amount, you can allow for that.  And it does seem to be very consistent across at least our 2 machines and possibly Grandchuck's too.

A simple 0.02% correction and now you have better than 10ppm.

The purpose of purchasing this scope was to be able to quickly diagnose SSB HF transceivers. But that's not possible with this deviation. I'd accept a deviation of +/- 100 Hz, but not this. It's a simple software adjustment.

[Atlan]

It's a simple software adjustment.

Programmers don't like this sentence. It may seem like a small change, but it can have far-reaching consequences

[PA2ER]

It's a simple software adjustment.

Programmers don't like this sentence. It may seem like a small change, but it can have far-reaching consequences

It's not that difficult, and with no consequences, to subtract 0.01916% from the frequency, in the routine where you enter the frequency. After warming up, it's stable within 0.5 Hz. So it could be a good stable generator.
I'm looking forward to the firmware where this has been fixed.

[PlainName]

The purpose of purchasing this scope was to be able to quickly diagnose SSB HF transceivers. But that's not possible with this deviation. I'd accept a deviation of +/- 100 Hz, but not this. It's a simple software adjustment.

I think you bought the wrong tool for your requirements. Kind of like buying a bicycle to go shopping.

[BillyO]

It's not that difficult, and with no consequences, to subtract 0.01916% from the frequency...

It's also not difficult to enter it manually either.  Took me about 10 seconds to enter a 0.02% correction that brought the error down to 420Hz.  That should be fine for HF SSB work.  Take another 5 seconds and you'd down to 20Hz.

I'm looking forward to the firmware where this has been fixed.

I wouldn't hold my breath for that.

I'm I'm of wondering where most of the people on this site got their education.  Where I went, the University of Toronto, at least half of the 1st and 2nd years physics labs concerned them selves with the detection of, calculation of, and ways to deal with error.  There is always error, and it's not always easy to detect and deal with.  Simple systematic error like this is easy to detect and deal with.  For most purposes the 0.02% error is fine.  For others, like HF radio, it's easy to take the error out.  It's not like it's all over the map.  It's consistent and repeatable.  0.02084% for me and 0.01916% for you.  Enter the correction and enjoy accurate measurements.

[BillyO]

Une un petit peu!

I make that mistake all the time.

[Ivont]

The generator stops working when the battery is below the middle.  Battery drains fast.  Noisy fan.  Lots of noise when measuring filters, constantly changing readings.  When measuring frequency, play after the decimal point.  Shuts down for no reason.  it does not know when the battery is fully charged and when it is discharged.