Author Topic: Difference in SWR readings between nanoVNA and SWR meter  (Read 1528 times)

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Offline vinlove

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #50 on: December 03, 2019, 07:48:50 am »
OK, mate it is not a big deal for me. It is just a 30£ nanoVNA, how accurate it is, I was just testing out.

But RadioListener, you are the one who spray this forum with bullshit, not me.
Read your own posts, and think. You are not interested in giving out anything helpful for the OP. You are only into putting down others points like a piece of dirt.  You keep on going about the problems that doesn't exist.

I would take the screen shots, if I trusted what you were saying, but I no longer take you as a serious forum member. Sorry.
I don't want to go and do what you suggest to do, and get slagged off by you for the rest of this century, because that is what you get pleasure from.

You go and do what you want, and what you think is right. I am going to stop wasting time reading any more of your post from this moment.
« Last Edit: December 03, 2019, 07:53:57 am by vinlove »
 

Offline vk6zgo

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #51 on: December 03, 2019, 08:09:08 am »
vinlove, this is not a specialist ham radio site.
I would suggest taking your original query to QRZ.com, where there are many people with experience of the type of antenna you are using.
 

Offline vinlove

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #52 on: December 03, 2019, 08:17:20 am »
That is now what I am realising VK6ZGO.

I think that Radiolistenr guy is a just short wave listener who has not even touched real transceiver and transmitting antenna in all of his life.  He is just jealous and bitter at the real licensed Hams, because he failed to pass his HAM Radio Exam, it sounds like.  He says that his radios and antennas are registered to somewhere. I have never heard of that kind of rubbish in my life.
 

Offline radiolistener

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #53 on: December 03, 2019, 08:32:47 am »
It is just a 30£ nanoVNA, how accurate it is, I was just testing out.

NanoVNA is much more accurate than any of your SWR meters, if you have any.
And you don't testing, you're trolling and insulting here. Nothing else.

But RadioListener, you are the one who spray this forum with bullshit, not me.

the bullshit here is just your posts. And all what you're doing here is just trolling.

People that needs help and answer won't write bullshit like that:

I don't have time to make screen shots of nanoVNA for this thread.

I don't need look at Smith Charts and make Screen Shots....

I would take the screen shots, if I trusted what you were saying, but I no longer take you as a serious forum member.

A lot of people asked you to provide measurements. But you still continue to ignore that and now you're started to insulting.

He says that his radios and antennas are registered to somewhere. I have never heard of that kind of rubbish in my life.

Where you from?

In my country the law requires government registration of transmitters and using unregistered transmitters is illegal even if you have license.

For example, this how it looks in the license:
883656-0
« Last Edit: December 03, 2019, 10:08:57 am by radiolistener »
 

Offline nali

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #54 on: December 03, 2019, 10:02:12 am »
OK, mate it is not a big deal for me. It is just a 30£ nanoVNA, how accurate it is, I was just testing out.

But RadioListener, you are the one who spray this forum with bullshit, not me.
Read your own posts, and think. You are not interested in giving out anything helpful for the OP. You are only into putting down others points like a piece of dirt.  You keep on going about the problems that doesn't exist.

vinlove If you'd take a break from spitting your dummy out you might notice that it was OwO who actually brought up the subject of earthing & counterpoise. And from reading the content of his and your posts I'd say his knowledge on the subject is a good couple or orders of magnitude higher than your own.

You're being given advice but not listening as it's not what you want to hear, a trait shared by at least one other in this thread.

(and yes, I do hold an AR licence, have done for 25 years)

 
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Offline m3vuv

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #55 on: December 03, 2019, 10:50:59 am »
i think radiolisteners radios are maybe registered with chicken bands r us!
 

Offline Yansi

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #56 on: December 03, 2019, 02:53:17 pm »
It's almost surprising how ignorant some people can be.
 

Offline G7OVK

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #57 on: December 03, 2019, 08:36:11 pm »
Vinlove, I have read every comment in this thread by radiolistener, and everything he says is completely accurate. Your knowledge of the subject is clearly lacking, and you don't seem to be willing to accept what you're being told.

You could start by providing the screenshots/information requested so that we can investigate further. If you're not willing to, don't expect to have your question properly resolved.
 
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Offline vk6zgo

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #58 on: December 04, 2019, 04:29:20 am »
Vinlove, I have read every comment in this thread by radiolistener, and everything he says is completely accurate. Your knowledge of the subject is clearly lacking, and you don't seem to be willing to accept what you're being told.
You could start by providing the screenshots/information requested so that we can investigate further. If you're not willing to, don't expect to have your question properly resolved.

Much of what radiolistener says, is indeed correct, but he, like vinlove, has become so absorbed in his narrative that he tends to "draw the long bow".
For example, in dismissing the suggestion of interference from a  nearby high powered RF source, he says:-

For VNA there is no needs band pass filter, because it already measure SWR for specific frequency with very narrow bandwidth. NanoVNA uses PLL synthesizer for frequency sweep and SA602 mixers to shift frequency down and digitize it with 48 kHz ADC, further processing is performed in digital domain.

From my reading of that, he is asserting that having high selectivity following the mixer will guarantee narrow bandwidth at the device input.
This is, of course, not the case.
Historically Superherodyne receivers have had at least one tuned circuit before the mixer, or at the very least a bandpass filter.

With an untuned mixer &, effectively, a low IF, image interference is probable, as is intermodulation between the wanted frequency & even widely disparate frequency sources if they are strong enough.

SWR bridges are normally so insensitive that they are used with high enough power levels to make direct reading of external carriers highly unlikely.

Before the "chest beating" starts, I will state that I have been an Amateur Radio Operator since 1977.
In my working career, I spent 30 plus years working with TV & Radio Broadcasting, the latter both FM & AM (MF & HF), as well as Communications transmitters & associated equipment, so maybe my opinion might just, possibly, be worth considering.

My advice to the OP to take it to QRZ.com is based upon the fact that hams are a minority on this site, & QRZ has some people who are very experienced in the use of the type of antenna he has, & can give him advice which isn't associated with the ongoing "aggro" in this thread.
Whether he choses to take it, is up to vinlove
 

Offline m3vuv

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #59 on: December 04, 2019, 05:08:04 am »
maybe this may help,found it on iogroups,sorted my issue out after pulling my hair out for almost 2 days! :Problem solved !

I'm running the new Nanovna-Q software from Nov. 26.
Before calibration I did the RESET, sure. The calibration resistors are OK, I have two, one that came with the NanoVna and one from MiniCircuits.

The RESET procedure was the problem:
 I did not realize that I also need to  SAVE to Cx right after Reset. Otherwise the data isn't really cleared and remains in the memory.
If I remember correctly in previous firmware versions the RESET automatically cleared the memory loction without having to save actively.

Whatsoever, now it works fine again.  Thanks for your inputs !
 

Offline radiolistener

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #60 on: December 04, 2019, 05:17:28 am »
I did not realize that I also need to  SAVE to Cx right after Reset. Otherwise the data isn't really cleared and remains in the memory.

This is incorrect information. There is no need to save calibration right after CAL RESET. Save is not required at all for calibration. You can save calibration at any time if it needs, but you can use calibration with no save until power off.

Save is needed just to be able to recall calibration later, for example after power off.

Also, when you're doing clearconfig command there is needs power off before any save operation, otherwise save operation will restore old bad configuration and it will needs to repeat clearconfig again.
« Last Edit: December 04, 2019, 05:50:39 am by radiolistener »
 

Online OwO

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #61 on: December 04, 2019, 05:38:14 am »
Historically Superherodyne receivers have had at least one tuned circuit before the mixer, or at the very least a bandpass filter.

With an untuned mixer &, effectively, a low IF, image interference is probable, as is intermodulation between the wanted frequency & even widely disparate frequency sources if they are strong enough.

SWR bridges are normally so insensitive that they are used with high enough power levels to make direct reading of external carriers highly unlikely.
This is all true, but in a VNA it's very easy to tell between external interferers and the true S11 response - the signal generator and the LO are phase coherent (when mixed down to DC with DSP you get a constant, unchanging vector) whereas any external interferers will have a random phase at any given time (unless they are somehow phase-locked to the same crystal as the LO). Hence the request for a smith chart which will very clearly tell you if you have an interferer problem or not. An interferer will show up as a "noisy" or "jagged" smith chart while physical devices will tend to have a "smooth" response provided you have enough resolution. This is also why I always say a cheap shitty VNA is better than a decent SNA because in a SNA (other than a few "special" models that are just a VNA with phase hidden from the user) you can not tell between an interferer and the device response and so are always "flying blind".
« Last Edit: December 04, 2019, 05:41:49 am by OwO »
Discord: スメグマ#2236
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Offline m3vuv

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #62 on: December 04, 2019, 06:29:42 am »
I did not realize that I also need to  SAVE to Cx right after Reset. Otherwise the data isn't really cleared and remains in the memory.
Thats total b.s!!you need to reset the call then save that slot before trying to write new cal data into it,otherwise it gets corupted!,dont take my word for it,try it!!

This is incorrect information. There is no need to save calibration right after CAL RESET. Save is not required at all for calibration. You can save calibration at any time if it needs, but you can use calibration with no save until power off.

Save is needed just to be able to recall calibration later, for example after power off.

Also, when you're doing clearconfig command there is needs power off before any save operation, otherwise save operation will restore old bad configuration and it will needs to repeat clearconfig again.
 

Offline radiolistener

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #63 on: December 04, 2019, 06:38:59 am »
From my reading of that, he is asserting that having high selectivity following the mixer will guarantee narrow bandwidth at the device input.
This is, of course, not the case.
Historically Superherodyne receivers have had at least one tuned circuit before the mixer, or at the very least a bandpass filter.

With an untuned mixer &, effectively, a low IF, image interference is probable, as is intermodulation between the wanted frequency & even widely disparate frequency sources if they are strong enough.

There is no bandpass filter on the mixers input in the NanoVNA, but as OwO mentioned above, REF and LO sources are phase coherent. And external sources are not coherent with REF and LO, so it doesn't affect measurement much. Of course if it's power level is not enough to overload mixers input.

For example here is a small test.

I connected 145 MHz antenna to NanoVNA and take measurement:
884216-0

After that I placed handheld radio near to antenna connected to NanoVNA and start transmission with about 5W power at 0.5 meter distance on 145.3 MHz and take second measurement on NanoVNA:
884220-1

As you understand, there is very strong interference from 5W transmitter near the measured antenna. But do you see any significant difference in VNA measurement? :)
 

Offline radiolistener

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #64 on: December 04, 2019, 06:42:48 am »
Thats total b.s!!you need to reset the call then save that slot before trying to write new cal data into it,otherwise it gets corupted!,dont take my word for it,try it!!

it gets more fun, especially when you wrote that you're using my firmware version.

I wrote you how to properly use it and now you wrote that this is bullshit...  :-DD :popcorn:
« Last Edit: December 04, 2019, 06:46:28 am by radiolistener »
 
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Offline m3vuv

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Re: Difference in SWR readings between nanoVNA and SWR meter
« Reply #65 on: December 04, 2019, 06:55:00 am »
NOTE: This message has been deleted by the forum moderator Simon for being against the forum rules and/or at the discretion of the moderator as being in the best interests of the forum community and the nature of the thread.
If you believe this to be in error, please contact the moderator involved.
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« Last Edit: December 04, 2019, 07:57:26 am by Simon »
 


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