Deepace KC901V 6.8GHz Handheld Network Analyzer Review, Teardown & Experiments

[Hugoneus]

In this episode Shahriar reviews the Deepace KC901V 6.8GHz handheld network analyzer. This battery-powered instrument is an RF multi-instrument integrating VNA, spectrum analyzer, field strength meter, and a low-frequency signal generator. It can also perform signal port vector measurement and 2-ports simple vector network analyzing (S11, S21). The review is organized as follows:

01:24 – Instrument overview & block diagram.
05:36 – Full teardown along with RF and digital board analysis.
14:30 – Power on, calibration and S11 measurement of an antenna.
23:46 – Calibration for S21 and measurement of a tunable filter plus phase shifter.
32:23 – Distance to fault measurement of an SMA cable chain.
36:24 – Spectrum analyzer measurements and limitations.
43:16 – Signal generator measurements and issues.
48:20 – Other features and concluding remarks.
50:07 – Giveaway!

You can watch it here: [51 Minutes]
youtu.be/LN9PKKdFibo

More videos at The Signal Path:
www.TheSignalPath.com

[Hugoneus]

CORRECTION: At 10:07 those components appear to be filters and not oscillators.

[technogeeky]

Pretty cool little device. And it's pretty cool they let you keep the parts unit they shipped to you, to give away. And it's pretty cool that you're giving it away!

Now I think I understand that my aforementioned Agilent E7495A must be doing S21 and S11 measurements on the RF out/in port. So the E7495A has at least a spectrum analyzer, CW, complex modulation on top of the CW, a VNA capable of doing one port S21 and S11 measurements, and also capable of doing two port S21 measurements also. And it of course also has DTF. I suppose the main disadvantage is that the lower limit on the CW output and therefore all of these measurements is 350 MHz, which is quite a limitation.

Anyway, the prospect of 1 in ~ 300 chance of getting the VNA enticed me to finally spend some money and become a patreon supporter. Have you decided when the cutoff/drawing will be held?

Thanks,
-tg

[Hugoneus]

Pretty cool little device. And it's pretty cool they let you keep the parts unit they shipped to you, to give away. And it's pretty cool that you're giving it away!

Now I think I understand that my aforementioned Agilent E7495A must be doing S21 and S11 measurements on the RF out/in port. So the E7495A has at least a spectrum analyzer, CW, complex modulation on top of the CW, a VNA capable of doing one port S21 and S11 measurements, and also capable of doing two port S21 measurements also. And it of course also has DTF. I suppose the main disadvantage is that the lower limit on the CW output and therefore all of these measurements is 350 MHz, which is quite a limitation.

Anyway, the prospect of 1 in ~ 300 chance of getting the VNA enticed me to finally spend some money and become a patreon supporter. Have you decided when the cutoff/drawing will be held?

Thanks,
-tg

I'll do a random draw later today.

Cheers,

[owiecc]

Can you link to the paper you mentioned at 17:30?

[hendorog]

Great work, just did the patreon thing as well.

[nowlan]

I was asking a local teacher/ham about spectrum analysers last month, and he recommended one of these instead.
I didnt see much about it on eevblog. A couple of really old posts that didnt go far.

[Hugoneus]

I was asking a local teacher/ham about spectrum analysers last month, and he recommended one of these instead.
I didnt see much about it on eevblog. A couple of really old posts that didnt go far.

Please keep in mind that this would not make a great spectrum analyzer as I have shown it's limitations during the review. The spectrum analysis is a secondary function of this unit.

[technogeeky]

I was asking a local teacher/ham about spectrum analysers last month, and he recommended one of these instead.
I didnt see much about it on eevblog. A couple of really old posts that didnt go far.

Please keep in mind that this would not make a great spectrum analyzer as I have shown it's limitations during the review. The spectrum analysis is a secondary function of this unit.

Especially for a beginner. Hooking up an excellent CW source like that and seeing absolutely nothing on the screen would be nearly baffling to a beginner. And that's the best case, where you know exactly where the signal would be. Imagine trying to find an unknown signal that way...

[rx8pilot]

At $2k, its a pretty cool device. Leaves room to get a proper spectrum analyzer and you would necessarily need one with a tracking generator.



Sent from my horrible mobile....

[TheSteve]

I was asking a local teacher/ham about spectrum analysers last month, and he recommended one of these instead.
I didnt see much about it on eevblog. A couple of really old posts that didnt go far.

Please keep in mind that this would not make a great spectrum analyzer as I have shown it's limitations during the review. The spectrum analysis is a secondary function of this unit.

Could they not include a mode that alternates between upper and lower LO's and then uses software to remove obvious high level images?
The small RBW is a bigger problem unless they want to add a massive amount of sample points which will probably really slow it down.

[technogeeky]

I was asking a local teacher/ham about spectrum analysers last month, and he recommended one of these instead.
I didnt see much about it on eevblog. A couple of really old posts that didnt go far.

Please keep in mind that this would not make a great spectrum analyzer as I have shown it's limitations during the review. The spectrum analysis is a secondary function of this unit.

Could they not include a mode that alternates between upper and lower LO's and then uses software to remove obvious high level images?
The small RBW is a bigger problem unless they want to add a massive amount of sample points which will probably really slow it down.

Plus, the resolution of the screen is an actual limitation here, isn't it?

[Hugoneus]

Could they not include a mode that alternates between upper and lower LO's and then uses software to remove obvious high level images?
The small RBW is a bigger problem unless they want to add a massive amount of sample points which will probably really slow it down.

Indeed this is possible and is regularly done with external mixers on various spectrum analyzers.

But as you said the second IF filter really limits this instrument on wide spans.

[Hugoneus]

It is definitely good that it has the SA function. Just can be a trap for beginners.

[Mechatrommer]

i bought this item few weeks ago, i tried to get sma calibration kit from MrKirkby specific to this product, he adviced to avoid this product because some flaws, such as we cant input calibration kit coefficients (stray capacitance or polynomial whatever it is) into the unit. i reported in their bbs forum, no reply from the engineers i guess they are sleeping, i emailed them they dont answer (they only answer when you want to buy this thing), now i cant access their website while others have no problem https://www.eevblog.com/forum/chat/need-human-verification-if-www-deepace-net-is-accesible/msg1329016/#msg1329016. bad service, not a recommended product i guess they successfully lured TheSignalPath to give a good review on this stuff and he havent look this thing into more details.

[chris_leyson]

Thanks Shahriar nice review, a great little instrument for dual band antenna design, like it.

[Hugoneus]

i guess they successfully lured TheSignalPath to give a good review on this stuff and he havent look this thing into more details.

Where do I start...

1) You can see the calibration screen and the parameters which can be entered clearly in my video:

youtu.be/LN9PKKdFibo?t=16m23s

2) The manual of the unit clearly states what can be entered:

S11 abides by SOL calibration, in which the three capital letters respectively
represent 3 types of calibrators: short, open and load.
KC951011/KC951012 is the SOL calibrator that we (Kexinshe) produced. Users can
also use other proper calibrators, but keep in mind that the terminal effect of the
chosen calibrators must be small enough since there is no compensation for KC901V
(non-commercial version). KC951011’s nominal electric length is 5.26mm and
KC951012’s one is 0. If a user chooses other standard, he/she needs to input the
value of the actual electric length in the FUNC interface.

I didn't give the unit a "good" review or "bad" review. I showed exactly what it can do and what its limitations are considering its price.

This is the second time (that I am aware of) in the past few weeks which you have smeared my work due to your own ignorance and self-entitlement.

[rx8pilot]

I think when he saw 'SOL' it was interpreted as 'Shit Out of Luck'   

[technogeeky]

Hugoneus:

In this video you mention that there is an interesting paper where the development of the various n-term (6-term, 12-term, etc) models for calibration of VNAs were developed -- that its a good paper and worth reading.

Can you give us a reference or a title so I can try to find it?

[Mechatrommer]

i guess they successfully lured TheSignalPath to give a good review on this stuff and he havent look this thing into more details.

Where do I start...
1) You can see the calibration screen and the parameters which can be entered clearly in my video:
youtu.be/LN9PKKdFibo?t=16m23s

i know that (i bought this unit remember?), but its just the mechanical offset length that is user adjustable. fringing effect offset to open standard, which is frequency dependent cannot be set.

2) The manual of the unit clearly states what can be entered:

S11 abides by SOL calibration, in which the three capital letters respectively
represent 3 types of calibrators: short, open and load.
KC951011/KC951012 is the SOL calibrator that we (Kexinshe) produced. Users can
also use other proper calibrators, but keep in mind that the terminal effect of the
chosen calibrators must be small enough since there is no compensation for KC901V
(non-commercial version). KC951011’s nominal electric length is 5.26mm and
KC951012’s one is 0. If a user chooses other standard, he/she needs to input the
value of the actual electric length in the FUNC interface.

meaning that... KC901V cannot be used with any calibration kit, even the most expensive one, if its not following the "terminal effect of the chosen calibrators must be small enough" criteria, let alone diy cal kit version. and how small is "small"? is anyone's and the KC901V's FW guesses.

I didn't give the unit a "good" review or "bad" review. I showed exactly what it can do and what its limitations are considering its price.

and many more comments as such before that... the only negative side you mentioned iirc is the limitation of SA functionality... but i tell you what, i still agree (and respect) in every aspects of what you said in the video, except you missed the most important limitation of the VNA (its main advertised purpose), ie it cannot user adjustable terminal (fringing capacitance) effect. this make the measurement output of the device is questionable. other expert highlighted that many advises in the manual are nonsensical, and you just highlighted one of it... how small is small the terminal effect? this is non-technical person writing the manual.

This is the second time (that I am aware of) in the past few weeks which you have smeared my work due to your own ignorance and self-entitlement.

except this, you seems to take things more seriously into personal affair. i try to shoot the other people but you seems to take the hit, too bad... the earlier one is one ignorance blaming tektronix due to their ads popping out infront of your video. blaming tektronix is blaming the wrong guy out of ignorance, i just tried to advice him, if "he has to blame" somebody, the video publisher should be more appropriate person to shoot at, but i dont mean you TheSignalPath is rightfully to be blamed, its just he liked to blame anybody. i cannot make counter reply to the post since the thread is locked (due to gender attack etc).

and now the 2nd time is this, i try to shoot deepace, but you take the hit, why? deepace paid you? i got pissed off by their incompetent at support service. even if how good their products are, if they dont bother to reply to their unsatisfied customers, would you still recommend them? who has to be blamed? the person who lure? or the person who got lured (victim)? i dont blame the victim ok. but instead of educating, warn people and look more into this matter seriously, you keep continue mourning how innocent you are and how perfect your reviews are that anybody cannot say negative about it, you only like to hear positive reply, then i guess you have some motive behind all of this, and my respect to you will go down logarithmitically. i'm sorry for the misunderstanding...

Regards...

[technogeeky]

There's a lot to attack in your post, but I'll just pick one specific thing and start there.

i guess they successfully lured TheSignalPath to give a good review on this stuff and he havent look this thing into more details.

and now the 2nd time is this, i try to shoot deepace, but you take the hit, why? deepace paid you?

Bullshit.

"I guess they successfully lured TheSignalPath" is clearly an attack on Shahriar's character, his credibility, and his openly stated values.

i got pissed off by their incompetent at support service. even if how good their products are, if they dont bother to reply to their unsatified customers, would you still recommend them? who has to be blamed? the person who lure? or the person who got lured (victim)? i dont blame the victim ok. but instead of educating, warn people and look more into this matter seriously

Two things:

• he made no attempt to review Deepace as a company
• he can't (to the best of my knowledge) see the future
• he doesn't have a fucking time machine

Criticizing his omission of a statement about poor product support from Deepace because you had a bad experience several months after he published his video requires the reasoning of a madman.

, you keep continue mourning how innocent you are and how perfect your reviews are that anybody cannot say negative about it, you only like to hear positive reply, then i guess you have some motive behind all of this, and my respect to you will go down logarithmitically.

Regards...

You didn't say something negative about his video, you said something negative about him. That's very different. I am not aware of any other electronics blogger who is as self-conscious about the quality and particularities of his videos, and it's completely unnecessary. It's assholes like you who go around incorrectly contributing to this self-doubt with attacks on his person which are partly to blame.

Furthermore, the idea that he's in the pocket of "big Deepace" is totally absurd, and that's a further insult to his intelligence. If you think a man who has access to multi-million dollar test equipment at work, and has a home lab with perhaps a quarter million dollars worth of quality test equipment from world-class vendors... if you think that same man is going to be corrupted by the mere offering of free thousand dollar piece of quasi-professional test equipment from some upstart company...

It's a wonder that you haven't made all of us insane on EEVblog forums with your level of critical thinking applied over those 8000 posts of yours.

[Mechatrommer]

• he made no attempt to review Deepace as a company

so any viewer who satisfy with the review will... buy an Agilent VNA?

• he can't (to the best of my knowledge) see the future

where in my statement expecting him to be?

• he doesn't have a fucking time machine

i dont reply to this childish statement.

Criticizing his omission of a statement about poor product support from Deepace because you had a bad experience several months after he published his video requires the reasoning of a madman.

related to his video, i dont expect him to know or give any comment on the company's support, but specifically on the VNA's limitation of terminal effect coefficient, he can correct that in this thread or in comment in youtube, just like he corrected his comment on filters vs oscillators mistake. continue claiming the perfection of his review is an act of self entitlement...

You didn't say something negative about his video, you said something negative about him.

where?

Furthermore, the idea that he's in the pocket of "big Deepace"

i wonder if you pass language subject in school or not, can you differ a statement with a question mark? yes the question is a provocation, but the answer to that will show the quality of the person...his choice...

It's assholes like you who go around...

keep up the good attitude, you think i'm buying it? nobody is God, i wont back somebody for the wrong cause just because he gave some good reviews and impression of expertise.

what i'm trying to say is he missed something a fact in his video, which a newbie like me figured out later. he may choose any intelligent way to defend (or admit it) the way he like. now he defended with a statement from Deepace's manual. if he expects anybody to understand what a "terminal effect" is by omitting it in the review, then fair enough... here again in this review thread, i say to all newbies out there like me, if you are thinking to buy KC901V just because you think its worth the price, then you should go and learn what is fringing capacitance effect means. if by neglecting the effect, the result is ok for you, then go buy this cheap thing, undoubtedly its the cheapest on the market for whats its claim for, but if the effect is of the concern, then be warned. i like to quote the other expert's saying in our conversation...

The problem I see with many places is they connect a VNA to something, and believe what it says. They don't actually know if it is correct or not...

[technogeeky]

keep up the good attitude, you think i'm buying it? nobody is God, i wont back somebody for the wrong cause just because he gave some good reviews and impression of expertise.

  

And what world-class microwave laboratory are you in charge of at your day job?

This is your third or fourth personal attack on Shahriar. And you just gloss over all of them.

There's no need for any of us to talk to you any longer.

[Mechatrommer]

And what world-class microwave laboratory are you in charge of at your day job?
This is your third or fourth personal attack on Shahriar

too much assumption on you i dont know where you are getting the imaginations. i dont blame you for thinking anybody you like as everything, its typical for a newcomers, i also once almost got sucked by this hypnosis

There's no need for any of us to talk to you any longer.

good lord, lets this thread as clean and as informative as it can be, not by anybody who are too emotional now lets get back to technicalities...

[all_repair]

You paid the school fee for us.  I was monitoring them on their Chinese forum.  But very uncomfortable with the way they coming out their products and their developments at the expense of their supporters.  They also raised their price rapdily.  A group of young techie trying to get rich very fast in a rapidly growing country.  My impression of them is they think they are very good, and so trying to get the rewards they think they should get.  This K... thing is a path they are trying out, and shall discard at the first instant.