Re: Unit Won't turn on after charging
My board says v4.2.1. Unfortunately I don't have an oscilloscope right now to check the xtals.
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Re: New H4 User and PC Software Question
Bob, move your mouse into the areas with the graphs and hit the right mouse button to bring up the control menu.?
Also search the forum messages for more info on Nanovna-App.?
On Sat., 19 Feb. 2022 at 11:47 a.m., montanaaardvark<boblombardi@...> wrote: I've subscribed to this group for a long time but never posted.? I only bought my first NanoVNA last weekend.? I bought an H4 for the larger screen.? Everything seems to be working fine.? I had an issue updating the firmware to DisLord's latest version from December, but that was Windows 10 being itself.? I got that fixed and updated the firmware.? I have a one-port antenna analyzer that I can compare its measurements to and everything seems close enough to be confident with it.?
My question concerns PC software with it.? I downloaded NanoVNA App after reading the Wiki, but since it doesn't have any documentation, can't find out ways to do things I'd like to do.? I don't think it's possible with this, so any pointers are appreciated.? Including if any other piece of software does these things better.
Simplest one first, I'd like to save the plots to S-parameter files.? Is that possible?
Is it possible to change the displays from Log Mag to magnitude and angle or R and jX?
On NanoVNA app, I see how to push the VNA settings onto the app, but I don't see how to push the app's settings onto the VNA.? Is that possible?
Thanks,
Bob
___________
Bob - W4ATM -? 35 miles south of the Kennedy Space Center
Retired RF Engineer now playing with all the hobbies I never had the time for.
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Re: Proper way to measure length of _Window_Line_?
Great post Bob, patient, thoughtful, and to the POINT. i.e. people do your homework before jumping into the 'fray'. There are lots of 'us' guys out there willing to help, but it is your responsibility to do your 'own' homework FIRST. That advice being, READ the original question and then go from there.
Mike C.
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Show quoted text
On 2/19/2022 7:40 AM, Bob Ecclestone VK2ZRE wrote: As happens so often in these threads, we need to go back to the original post and read the question.
Kevin was puzzled as to why his S11 results did not show a distinct "short" when he tested his 300 Ohm ladderline connected directly to his NanoVNA unbalanced 50 Ohm S11 port.
He posted the sweep results in that original post..
Some folks offered possible reasons, others possible work arounds. But no one explained to him why he got the results he did. No one ANSWERED his original question.
I am not going to dispute any of the subsequent comments made regarding direct connections, common mode chokes or anything else posted here.
I offered one possible solution using a broadband impedance matching transformer because it is quite possible that Kevin is actually building an antenna being fed with 300 Ohm ladderline and that by building the transformer, he could verify his stub and then go on to test the completed antenna. As the system is now impedance matched back to 50 Ohms, his S11 results on the complete antenna system would now better reflect (pun intended) the actual system performance.
If folk are not comfortable winding their own transformers, there are bare transformers and packaged units readily available on the web.
If you are comfortable winding your own, it is almost as easy to wind a 300/50 matching transformer as it is a CM choke.
The difference is, you now have a piece of test kit specific to the task at hand.
The task in this case centres around 300 Ohm ladderline.
I do not know why Kevin got the results he did originally, but I am confident that if he uses a matching transformer, the results he gets next time should be closer to what he expects.
And as a final comment, the ladderline stub should be tested and trimmed well clear of any thing as even moisture on a non conducting pole will be enough to add distributed capacitance across the line and affect the apparent Velocity Factor. Metal, including other cables, in close proximity is a definite no no.
Which brings me to offer a possible REASON for Kevin's results.
He states he had 5.175m of "JSC 1320" cable. A quick check of the specs for 1320 ladderline gives a VF of 0.82
Therefore the ELECTRICAL wavelength of the line is 4(5.175/0.82) = 25.24m. This gives a frequency of 300/25.24 = 11.89MHz
Since Kevin only started his sweep at 12MHz, he did not sweep the actual stub frequency of 11.89MHz.
If the ladderline was lying on the ground or close to any metal, the "apparent" VF would be even lower and the electrical length and thus quarterwave frequency would be even lower again.
Looking at the Smith Chart, we can see it is approaching a zero Z but does not quite make it. Why? Because he should have started the sweep at a lower frequency.
That's my theory anyway.
So it pays to go back and read the entire original post.
73...Bob VK2ZRE
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New H4 User and PC Software Question
I've subscribed to this group for a long time but never posted. I only bought my first NanoVNA last weekend. I bought an H4 for the larger screen. Everything seems to be working fine. I had an issue updating the firmware to DisLord's latest version from December, but that was Windows 10 being itself. I got that fixed and updated the firmware. I have a one-port antenna analyzer that I can compare its measurements to and everything seems close enough to be confident with it.
My question concerns PC software with it. I downloaded NanoVNA App after reading the Wiki, but since it doesn't have any documentation, can't find out ways to do things I'd like to do. I don't think it's possible with this, so any pointers are appreciated. Including if any other piece of software does these things better.
Simplest one first, I'd like to save the plots to S-parameter files. Is that possible?
Is it possible to change the displays from Log Mag to magnitude and angle or R and jX?
On NanoVNA app, I see how to push the VNA settings onto the app, but I don't see how to push the app's settings onto the VNA. Is that possible?
Thanks,
Bob
___________
Bob - W4ATM -? 35 miles south of the Kennedy Space Center
Retired RF Engineer now playing with all the hobbies I never had the time for.
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Re: Proper way to measure length of _Window_Line_?
As happens so often in these threads, we need to go back to the original post and read the question.
Kevin was puzzled as to why his S11 results did not show a distinct "short" when he tested his 300 Ohm ladderline connected directly to his NanoVNA unbalanced 50 Ohm S11 port.
He posted the sweep results in that original post..
Some folks offered possible reasons, others possible work arounds. But no one explained to him why he got the results he did. No one ANSWERED his original question.
I am not going to dispute any of the subsequent comments made regarding direct connections, common mode chokes or anything else posted here.
I offered one possible solution using a broadband impedance matching transformer because it is quite possible that Kevin is actually building an antenna being fed with 300 Ohm ladderline and that by building the transformer, he could verify his stub and then go on to test the completed antenna. As the system is now impedance matched back to 50 Ohms, his S11 results on the complete antenna system would now better reflect (pun intended) the actual system performance.
If folk are not comfortable winding their own transformers, there are bare transformers and packaged units readily available on the web.
If you are comfortable winding your own, it is almost as easy to wind a 300/50 matching transformer as it is a CM choke.
The difference is, you now have a piece of test kit specific to the task at hand.
The task in this case centres around 300 Ohm ladderline.
I do not know why Kevin got the results he did originally, but I am confident that if he uses a matching transformer, the results he gets next time should be closer to what he expects.
And as a final comment, the ladderline stub should be tested and trimmed well clear of any thing as even moisture on a non conducting pole will be enough to add distributed capacitance across the line and affect the apparent Velocity Factor. Metal, including other cables, in close proximity is a definite no no.
Which brings me to offer a possible REASON for Kevin's results.
He states he had 5.175m of "JSC 1320" cable. A quick check of the specs for 1320 ladderline gives a VF of 0.82
Therefore the ELECTRICAL wavelength of the line is 4(5.175/0.82) = 25.24m. This gives a frequency of 300/25.24 = 11.89MHz
Since Kevin only started his sweep at 12MHz, he did not sweep the actual stub frequency of 11.89MHz.
If the ladderline was lying on the ground or close to any metal, the "apparent" VF would be even lower and the electrical length and thus quarterwave frequency would be even lower again.
Looking at the Smith Chart, we can see it is approaching a zero Z but does not quite make it. Why? Because he should have started the sweep at a lower frequency.
That's my theory anyway.
So it pays to go back and read the entire original post.
73...Bob VK2ZRE
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Re: NanoSaver on ubuntu- mint
Hello, I install LibreVNA and work, I use the USB port for different device and work, the only problem is NanoVNA-Saver is installed but not find the the serial/usb device. *Sent:* Saturday, February 19, 2022 at 4:36 AM *From:* "Dragan Milivojevic" <d.milivojevic@...> *To:* [email protected]*Subject:* Re: [nanovna-users] NanoSaver on ubuntu- mint
On Sat, 19 Feb 2022 at 01:22, Francesco <realfran@...> wrote: Hello, I set up one laptop with Mint Linux "cinnamon" I install NanoVNA
Saver I don't find the "device port" get a problem with the LiteVNA and the
NanoVNA V2 plus4.
Please some help, I'm computer illiterate and this is the first time I use
Linux (I'm lost) I install a lot of Python libraries and I get confused
with the " CONSOLE "
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Re: NanoSaver on ubuntu- mint
toggle quoted message
Show quoted text
On Sat, 19 Feb 2022 at 01:22, Francesco <realfran@...> wrote: Hello, I set up one laptop with Mint Linux "cinnamon" I install NanoVNA
Saver I don't find the "device port" get a problem with the LiteVNA and the
NanoVNA V2 plus4.
Please some help, I'm computer illiterate and this is the first time I use
Linux (I'm lost) I install a lot of Python libraries and I get confused
with the " CONSOLE "
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NanoSaver on ubuntu- mint
Hello, I set up one laptop with Mint Linux "cinnamon" I install NanoVNA Saver I don't find the "device port" get a problem with the LiteVNA and the NanoVNA V2 plus4.
Please some help, I'm computer illiterate and this is the first time I use Linux (I'm lost) I install a lot of Python libraries and I get confused with the " CONSOLE "
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Yes I should check R and may give me a clue.
I have a junk unit that screen broke, I was using with computer and did a update and now won¡¯t come on.
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Re: Unit Won't turn on after charging
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Re: Unit Won't turn on after charging
I believe that your problem is a bad battery that won't take a charge,
therefore, it wont start either!
V. Kaufman
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On Thu, Feb 17, 2022, 15:26 Larry Rothman <nlroth@...> wrote: Check the rocket switch with an ohmmeter to verify all 3 switches are
normally open.
On Thu., 17 Feb. 2022 at 4:32 p.m., Brady Nelson<tbradynelson@...>
wrote: I did have some trouble with the button when it was working, but I
keep messing with the button to see if I can get it to start, no luck.
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I have a smaller one that the screen was damaged so maybe I will have spare parts.
I¡¯m I did check the resistors the other day and showed good.
I will see it I can find that schematic so figure out what tbe SA16 part you mentioned, I do have a heat gun so can use the to remove parts
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On 2/17/22 3:41 PM, Jim Lux wrote: On 2/17/22 12:57 PM, Larry Rothman wrote:
? Alan,
The schematics are in the Wiki.
There are only resistors in the input pad. You need to measure them to see which is fried. Hopefully, you didn't fry the SA612 input.
If you have 2 soldering irons with fine tips, you can lift each off the board easily but remember the display is on the other side of the PCB - so not too much heat.
It's not that hard - I flipped the resistors on my Nano-H to see if it helped with the noise (msg thread on that in 2019).
If you have a junk box, you might be able to find replace SMT resistors on scrap boards.
???? On Thursday, February 17, 2022, 03:44:55 p.m. EST, Alan Brown via groups.io <va3aqb@...> wrote:
? ? So S21 has been damaged when I was checking a LNA, i gapped it for 2 seconds and hooked the attenuator on the wrong side.
It is a H4, I was going to order a new one as needed pass through on most things I use it for.
Anyone know how to fix, is there a diode or anything that blows when input is to high?
The resistors are cheap, too. I just heat them, and scrape them off with an xacto knife.? Before surgery, you can check: If you cooked one, the resistance will be wrong.? The SA612 is DC blocked, so you can calculate what DC resistance you should see from the CH1 connector (56 ohms , in parallel with 2*240+50 ohms - probably pretty close to 50 ohms) I just measured about 50.5 ohms dc resistance.
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On 2/17/22 12:57 PM, Larry Rothman wrote: Alan,
The schematics are in the Wiki.
There are only resistors in the input pad. You need to measure them to see which is fried. Hopefully, you didn't fry the SA612 input.
If you have 2 soldering irons with fine tips, you can lift each off the board easily but remember the display is on the other side of the PCB - so not too much heat.
It's not that hard - I flipped the resistors on my Nano-H to see if it helped with the noise (msg thread on that in 2019).
If you have a junk box, you might be able to find replace SMT resistors on scrap boards.
On Thursday, February 17, 2022, 03:44:55 p.m. EST, Alan Brown via groups.io <va3aqb@...> wrote:
So S21 has been damaged when I was checking a LNA, i gapped it for 2 seconds and hooked the attenuator on the wrong side.
It is a H4, I was going to order a new one as needed pass through on most things I use it for.
Anyone know how to fix, is there a diode or anything that blows when input is to high?
The resistors are cheap, too. I just heat them, and scrape them off with an xacto knife.? Before surgery, you can check: If you cooked one, the resistance will be wrong.? The SA612 is DC blocked, so you can calculate what DC resistance you should see from the CH1 connector (56 ohms , in parallel with 2*240+50 ohms - probably pretty close to 50 ohms)
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On 2/17/22 12:44 PM, Alan Brown via groups.io wrote: So S21 has been damaged when I was checking a LNA, i gapped it for 2 seconds and hooked the attenuator on the wrong side.
It is a H4, I was going to order a new one as needed pass through on most things I use it for.
Anyone know how to fix, is there a diode or anything that blows when input is to high? As previously described, (see attached schematic ) there's a resistive pad (E2, R22,R23,R24, R25) then the SA612AD ( E4, U8.) I doubt it would blow up anything else that's connected (that is, the SA612 protects the ADC in U9) I don't have the -H4 schematic handy, but it's similar (the big difference is the screen size).
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Re: Unit Won't turn on after charging
Check the rocket switch with an ohmmeter to verify all 3 switches are normally open.
On Thu., 17 Feb. 2022 at 4:32 p.m., Brady Nelson<tbradynelson@...> wrote: I did have some trouble with the button when it was working, but I keep messing with the button to see if I can get it to start, no luck.
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On Thu, Feb 17, 2022 at 12:44 PM, Alan Brown wrote:
So S21 has been damaged when I was checking a LNA, i gapped it for 2 seconds
and hooked the attenuator on the wrong side.
It is a H4, I was going to order a new one as needed pass through on most
things I use it for.
Anyone know how to fix, is there a diode or anything that blows when input is
to high?
I posted the schematics in the other post you made on this subject.. Roger
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Re: Unit Won't turn on after charging
I did have some trouble with the button when it was working, but I keep messing with the button to see if I can get it to start, no luck.
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I blew my vna after connection to a cheap digital attenuator, current surge blew out front end. Use only passive fixed attenuators now. On Thu, Feb 17, 2022, 3:55 PM Alan Brown via groups.io <va3aqb= [email protected]> wrote: So S21 has been damaged when I was checking a LNA, i gapped it for 2
seconds and hooked the attenuator on the wrong side.
It is a H4, I was going to order a new one as needed pass through on most
things I use it for.
Anyone know how to fix, is there a diode or anything that blows when input
is to high?
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Mike C.
Francesco
Alan Brown
Roger Need