Re: danger measuring antenna
One useful solution is to use a shunt resistor or a shunt inductor. Many antenna installations will include a resistor or a choke from the "hot" side of the coax to ground. The impedance of the shunt element is selected to be high enough that it's effectively "invisible" to the frequencies of interest, but low enough that it allows (high-voltage, low-current) static electricity to drain away safely to ground.
If, for example, you want to measure a typical 50-ohm-nominal antenna system which has BNC or "UHF" connectors, buy yourself a "T" adapter for the connector type you use, and buy a spare male plug of that sort as well. Solder a 10k or 100k-ohm resistor into the spare plug, and (at the same time) solder a length of wire and a ground clip to the "shell" side of the connector. When you want to measure an antenna, first clip the ground wire of the T adapter to a good ground, and then connect the antenna wire to one arm of the T. This will ground the coax braid, and allow any static buildup on the inner conductor to drain away through the drain resistor. Then, connect the other arm of the "T" to your measurement device (e.g. nanoVNA). 100k in parallel with the actual feed-point impedance won't make a measurable difference in what you read.
This is one instance in which old-style "carbon composition" resistors are very well suited - they're non-inductive, and they tend to be tolerant of high-voltage spikes. The fact that they're often noisy and "drifty" matters not at all in this application.
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I'm glad to hear that the memory card worked, I also really missed this opportunity, so I implemented it for myself (but use different hardware, in it SD card already installed and 32768 xtal present and RTC work).
Unfortunately, the hardware in v2 does not allow the clock to start, and because of this, the file names (RTC used for create filename) may be repeated (the clock starts to run again when starting from 0)
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Hi DiSlord, I soldered the holder, inserted a 10R resistor into the 3.3V power supply, connected the signals and the SD card works ;) For the first time, .bmp, .s1p, .s2p were written to my card without any problems. I missed the prinscreen function very much when measuring antennas outside the house without a computer, therefore thank you very much for sharing this opportunity. Tomorrow I will adjust the cabinet, add a hole, fasten the wires. Photos: /g/NanoVNAV2/album?id=267148
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Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
Hi DiSlord, I don't know if I continue in this thread or in /g/nanovna-users/message/23642I soldered the holder, inserted a 10R resistor into the 3.3V power supply, connected the signals and the SD card works ;) For the first time, .bmp, .s1p, .s2p were written to my card without any problems. I missed the prinscreen function very much when measuring antennas outside the house without a computer, therefore thank you very much for sharing this opportunity. Tomorrow I will adjust the cabinet, add a hole, fasten the wires. Photos: /g/NanoVNAV2/album?id=267148
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Re: Transform: Time Domain Band Pass
On 8/16/21 12:09 PM, Syd via groups.io wrote: In the manual there is a Transform setup for the bandpass mode and here is the picture of the results attached. I think this setup is strictly for measuring band pass filters, correct me if I'm wrong. From the pix I can see that the time being scanned from the frequency setup is from 0 ns to 43 ns shown on the bottom. From what I am seeing I think ch0 shows the pulse being generated and ch1 is showing the results from the BPF. not exactly, what you're seeing is the pulse that would be *reflected* back from the UUT for CH0, and the pulse that would be transmitted for CH1. The 20.0n/-0.14 and 10.0n/-0.02 scaling for ch0 and ch1 at the top I thought was showing the scaling per division and the level, but now I am not sure what it is telling me. Perhaps the reflection coefficient magnitude? Then again the white marker notation is showing 4ns 0.4m? How do I interpret that? The basic measurement is in time, so some assumed velocity factor is being used to turn that into distance.? The reflected pulse is 4ns, so the 1 way time is 2ns, and that probably works out to 0.4m.? (in free space, 2ns would be ~60cm, so with a VF of 66%, that would be 40cm, I think. Additionally, what is the TDR measurement of a band pass filter giving me information wise that I can't get from scanning the BPF and looking at the logmax output over a span of frequencies? Not much.? It's not a commonly used way to look at filters. At least from the logmax method I can see the characteristics of the filter, and I don't see anything like it with this method since it is in the time domain. Time domain is interesting if you're wondering about group delay and dispersion.? If you have a SAW filter, sometimes you can see "triple transit" effects as a peak at 3x the nominal delay.? It's also interesting if you're concerned about envelope distortion. syd/wt1v
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Re: Transform: Time Domain Band Pass
On Mon, Aug 16, 2021 at 12:09 PM, Syd wrote:
In the manual there is a Transform setup for the bandpass mode and here is the
picture of the results attached. I think this setup is strictly for measuring
band pass filters, correct me if I'm wrong. From the pix I can see that the
time being scanned from the frequency setup is from 0 ns to 43 ns shown on the
bottom. From what I am seeing I think ch0 shows the pulse being generated and
ch1 is showing the results from the BPF. The 20.0n/-0.14 and 10.0n/-0.02
scaling for ch0 and ch1 at the top I thought was showing the scaling per
division and the level, but now I am not sure what it is telling me. Then
again the white marker notation is showing 4ns 0.4m? How do I interpret that?
Additionally, what is the TDR measurement of a band pass filter giving me
information wise that I can't get from scanning the BPF and looking at the
logmax output over a span of frequencies? At least from the logmax method I
can see the characteristics of the filter, and I don't see anything like it
with this method since it is in the time domain.
syd/wt1v
This feature is not restricted to measuring bandpass filters. The TDR mode uses an IFFT algorithm on VNA frequency data to get a time domain display. This is useful when finding distance to a fault or the length of a transmission line When measuring a device under test (DUT) it gives the impulse response which is the time domain equivalent of the frequency response. Selecting "bandpass" mode is useful when measuring transmission lines with DC blocking or filtered transmission lines. It is the mode to use when setting a stimulus frequency well above DC. You can read more about this in this app note by Agilent. The bandpass mode is described on page 13. Roger
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Re: Transform: Time Domain Band Pass
Filters ring when you pulse them.
toggle quoted message
Show quoted text
On Monday, August 16, 2021, 02:10:02 PM CDT, Syd via groups.io <nhuq1@...> wrote:
In the manual there is a Transform setup for the bandpass mode and here is the picture of the results attached.? I think this setup is strictly for measuring band pass filters, correct me if I'm wrong.? From the pix I can see that the time being scanned from the frequency setup is from 0 ns to 43 ns shown on the bottom. From what I am seeing I think ch0 shows the pulse being generated and ch1 is showing the results from the BPF. The 20.0n/-0.14 and 10.0n/-0.02 scaling for ch0 and ch1 at the top I thought was showing the scaling per division and the level, but now I am not sure what it is telling me.? Then again the white marker notation is showing 4ns 0.4m?? How do I interpret that? Additionally, what is the TDR measurement of a band pass filter giving me information wise that I can't get from scanning the BPF and looking at the logmax output over a span of frequencies?? At least from the logmax method I can see the characteristics of the filter, and I don't see anything like it with this method since it is in the time domain.
syd/wt1v
|
Transform: Time Domain Band Pass
In the manual there is a Transform setup for the bandpass mode and here is the picture of the results attached. I think this setup is strictly for measuring band pass filters, correct me if I'm wrong. From the pix I can see that the time being scanned from the frequency setup is from 0 ns to 43 ns shown on the bottom. From what I am seeing I think ch0 shows the pulse being generated and ch1 is showing the results from the BPF. The 20.0n/-0.14 and 10.0n/-0.02 scaling for ch0 and ch1 at the top I thought was showing the scaling per division and the level, but now I am not sure what it is telling me. Then again the white marker notation is showing 4ns 0.4m? How do I interpret that? Additionally, what is the TDR measurement of a band pass filter giving me information wise that I can't get from scanning the BPF and looking at the logmax output over a span of frequencies? At least from the logmax method I can see the characteristics of the filter, and I don't see anything like it with this method since it is in the time domain.
syd/wt1v
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Re: help with driver issue for a newbie
Hello Ray!
Please try here:
Driver and software :
without driver works Your nanoVNA V2 not!
Also, first driver, second software and fw update
Here is user manual
Best regards
Vladimir, dl7pga
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Re: help with driver issue for a newbie
Have you looked over in either of the nanovna-V2 forums? I just found this thread there: /g/NanoVNA-V2/topic/win_10_issue/77411380?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,80,77411380
On Monday, August 16, 2021, 12:40:41 p.m. EDT, Ray <boxman@...> wrote:
Hi All,
I am having a frustrating driver issue. It is all the more frustrating because at some point I succeeded in controlling my nanoVNA from various software packages from my laptop, and was all set to study the various options, choose the one most suitable for me, and get to work! But currently, the computer and the nanoVNA do not appear to talk with each other.
I have no idea of which nanoVNA v. 2 variant I have, but please see the attached photo. Under version, it states that the hardware was designed by OwoComm. I purchase it from Ali Express for $62.? I am trying to connect with a relatively recent Lenovo laptop running Windows 10 pro. It just did an update to version 20H2 (today) but I had the same problem before and after the update. I have the following symptoms:
1.? ? ? When I plug in the USB cable, the nanoVNA screen remains active.
2.? ? ? When I plug in or disconnect the USB cable, I get a characteristic dong from the laptop, but I do not observe any difference in the device manager display.
3.? ? ? What appears in the device manager display under ports is "STMicroelectronics Virtual COM port (COM4)" together with the yellow triangular warning icon, whether the nanoVNA is connected regularly, or in DFU mode, or disconnected (see attached screen shot).
4.? ? ? If I right click on this and look at properties, I get
a.? ? ? (general), "The device cannot start (Code 10). The specified request is not a valid operation for the target device
b.? ? ? (driver): driver version 1.4.0.0, driver date 2-Aug-13
c.? ? ? (Events): information: Device ROOT\PORTS\0000 requires further installation
I followed the procedure in Absolute Beginner's Guide to NanoVNA by Martin Svaco, 9A2JK, and in particular tried all of the methods suggested in the TROUBLESHOOTING THE DRIVER INSTALLATION section. Before today's update, I also used CCleaner to clean-up the registry. But all to no avail. I tried updating, uninstalling, reinstalling, the driver etc., but nothing alleviated the above described symptoms.
I would value any and all advice!
73,
Ray 4X1RB
From the home of
Prof. Emeritus Raymond (Reuven) Boxman
School of Electrical Engineering
Tel Aviv University
Cell:? ? ? +972 544 634 217
CEO Clear Wave Ltd.? ? ? ? ? ? ? ? <>
Scientific Writing Courses:? ? ? ? <>
|
help with driver issue for a newbie
Hi All,
I am having a frustrating driver issue. It is all the more frustrating because at some point I succeeded in controlling my nanoVNA from various software packages from my laptop, and was all set to study the various options, choose the one most suitable for me, and get to work! But currently, the computer and the nanoVNA do not appear to talk with each other.
I have no idea of which nanoVNA v. 2 variant I have, but please see the attached photo. Under version, it states that the hardware was designed by OwoComm. I purchase it from Ali Express for $62. I am trying to connect with a relatively recent Lenovo laptop running Windows 10 pro. It just did an update to version 20H2 (today) but I had the same problem before and after the update. I have the following symptoms:
1. When I plug in the USB cable, the nanoVNA screen remains active.
2. When I plug in or disconnect the USB cable, I get a characteristic dong from the laptop, but I do not observe any difference in the device manager display.
3. What appears in the device manager display under ports is "STMicroelectronics Virtual COM port (COM4)" together with the yellow triangular warning icon, whether the nanoVNA is connected regularly, or in DFU mode, or disconnected (see attached screen shot).
4. If I right click on this and look at properties, I get
a. (general), "The device cannot start (Code 10). The specified request is not a valid operation for the target device
b. (driver): driver version 1.4.0.0, driver date 2-Aug-13
c. (Events): information: Device ROOT\PORTS\0000 requires further installation
I followed the procedure in Absolute Beginner's Guide to NanoVNA by Martin Svaco, 9A2JK, and in particular tried all of the methods suggested in the TROUBLESHOOTING THE DRIVER INSTALLATION section. Before today's update, I also used CCleaner to clean-up the registry. But all to no avail. I tried updating, uninstalling, reinstalling, the driver etc., but nothing alleviated the above described symptoms.
I would value any and all advice!
73,
Ray 4X1RB
From the home of
Prof. Emeritus Raymond (Reuven) Boxman
School of Electrical Engineering
Tel Aviv University
Cell: +972 544 634 217
CEO Clear Wave Ltd. <>
Scientific Writing Courses: <>
|
Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
Obviously you haven't since the emails keep coming. On Mon, 16 Aug 2021 at 13:15, Knud Jorgen Olsen-Jensen via groups.io <vk2kjj@...> wrote: Stop sending the e-mail to me. I have even left the Group because I could
not stop the mails
CW4EVER
On 16 Aug 2021, at 19:31, Anton <om1aeg@...> wrote:
?Thank you for your reply DiSlord. I looked at both PCBs, 10R resistor for 3.3V I put in position R2 on "LCD" PCB, MOSI signals, MISO, SCLK are
available on H1 connector on "LCD" PCB. The problem will be to get the PB9
(CS) signal out of U303:46, directly from U303 pin, no trace on PCB.
|
See the bottom of each email for the link
toggle quoted message
Show quoted text
On Aug 15, 2021, at 20:10, Knud Jorgen Olsen-Jensen via groups.io <vk2kjj@...> wrote:
?Don¡¯t send me your emails
CW4EVER
On 16 Aug 2021, at 09:15, Charles KC6UFM <kc6ufm@...> wrote:
?Hi, Luciano...
I more or less (in my head) wrote off the "extra" resistance needed to make
the NanoVNA see a flat match as being to a combination of lead
resistance/reactance and operator error.
I think it's safe to assume that the transformer is actually a 49:1 ratio.
Thanks!
On Sun, Aug 15, 2021 at 3:48 PM Luciano Luciano <luciano.wdc@...>
wrote:
Hi Charles,
I get "suspicious" when I see small differences like this i.e. 50 ohm as
in this case. Assuming the black box is lossless, you should measure either
2450 or 2500 ohm if you load the other port (with coax connector, right?)
with 50 ohm... if you measure 2450 then it is a 49:1 transformer as you
correctly guessed in the first place! Of course easier to say (and write)
in theory than to actually do in practice.
Regards,
Luciano
On Sun, Aug 15, 2021, 6:15 PM Charles KC6UFM <kc6ufm@...> wrote:
Hello, All...
I recently had a need to measure an unknown matching transformer. As it
was
in a sealed enclosure with noth but the wire terminal and coax connector
exposed, and I didn't want to damage the enclosure, I pulled out my trusty
NanoVNA.
All I knew about the "black box" was that it was used with a
10-12-15-17-20m EFHW wire antenna. That made me assume it would be
somewhere in the range of a 49:1 ratio.
I pulled out my decade resistance box and dialed in 2450 ohms (50 ohms x
49) and put that between the output wire terminal and ground. I then
connected the NanoVNA to the coax input.
I then played with the decade box until I got a flat response from the
NanoVNA and the needed resistance to get there was 2501 ohms. Technically,
that makes the matching network about 50:1 ratio.
All of this told me what I wanted to know, but I'm wondering if there would
be an easier, more direct way of getting there with the NanoVNA.
I'm good with the idea that I may have just stumbled onto the right answer
in my madness.
Take Care & 73
--
de KC6UFM
Charles
--
de KC6UFM
Charles
|
Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
Stop sending the e-mail to me. I have even left the Group because I could not stop the mails You need go /g/nanovna-users/editsub and select No Email for disable receive group messages
|
Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
Stop sending the e-mail to me. I have even left the Group because I could not stop the mails
CW4EVER
toggle quoted message
Show quoted text
On 16 Aug 2021, at 19:31, Anton <om1aeg@...> wrote:
?Thank you for your reply DiSlord. I looked at both PCBs, 10R resistor for 3.3V I put in position R2 on "LCD" PCB, MOSI signals, MISO, SCLK are available on H1 connector on "LCD" PCB. The problem will be to get the PB9 (CS) signal out of U303:46, directly from U303 pin, no trace on PCB.
|
Re: Download NanaoVNA Labview
From the NI MAX web site: "NI MAX is only supported on Windows and MacOS, not Linux, and cannot be downloaded by itself. It is included with all NI drivers (NI-VISA, NI-DAQmx etc.) and NI System Configuration."
73, Don N2VGU
|
Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
Thank you for your reply DiSlord. I looked at both PCBs, 10R resistor for 3.3V I put in position R2 on "LCD" PCB, MOSI signals, MISO, SCLK are available on H1 connector on "LCD" PCB. The problem will be to get the PB9 (CS) signal out of U303:46, directly from U303 pin, no trace on PCB.
|
Don¡¯t send me your emails
CW4EVER
toggle quoted message
Show quoted text
On 16 Aug 2021, at 10:10, Knud Jorgen Olsen-Jensen via groups.io <vk2kjj@...> wrote:
?Don¡¯t send me your emails
CW4EVER
On 16 Aug 2021, at 09:15, Charles KC6UFM <kc6ufm@...> wrote:
?Hi, Luciano...
I more or less (in my head) wrote off the "extra" resistance needed to make
the NanoVNA see a flat match as being to a combination of lead
resistance/reactance and operator error.
I think it's safe to assume that the transformer is actually a 49:1 ratio.
Thanks!
On Sun, Aug 15, 2021 at 3:48 PM Luciano Luciano <luciano.wdc@...>
wrote:
Hi Charles,
I get "suspicious" when I see small differences like this i.e. 50 ohm as
in this case. Assuming the black box is lossless, you should measure either
2450 or 2500 ohm if you load the other port (with coax connector, right?)
with 50 ohm... if you measure 2450 then it is a 49:1 transformer as you
correctly guessed in the first place! Of course easier to say (and write)
in theory than to actually do in practice.
Regards,
Luciano
On Sun, Aug 15, 2021, 6:15 PM Charles KC6UFM <kc6ufm@...> wrote:
Hello, All...
I recently had a need to measure an unknown matching transformer. As it
was
in a sealed enclosure with noth but the wire terminal and coax connector
exposed, and I didn't want to damage the enclosure, I pulled out my trusty
NanoVNA.
All I knew about the "black box" was that it was used with a
10-12-15-17-20m EFHW wire antenna. That made me assume it would be
somewhere in the range of a 49:1 ratio.
I pulled out my decade resistance box and dialed in 2450 ohms (50 ohms x
49) and put that between the output wire terminal and ground. I then
connected the NanoVNA to the coax input.
I then played with the decade box until I got a flat response from the
NanoVNA and the needed resistance to get there was 2501 ohms. Technically,
that makes the matching network about 50:1 ratio.
All of this told me what I wanted to know, but I'm wondering if there would
be an easier, more direct way of getting there with the NanoVNA.
I'm good with the idea that I may have just stumbled onto the right answer
in my madness.
Take Care & 73
--
de KC6UFM
Charles
--
de KC6UFM
Charles
|
Don¡¯t send me your emails
CW4EVER
toggle quoted message
Show quoted text
On 16 Aug 2021, at 09:15, Charles KC6UFM <kc6ufm@...> wrote:
?Hi, Luciano...
I more or less (in my head) wrote off the "extra" resistance needed to make
the NanoVNA see a flat match as being to a combination of lead
resistance/reactance and operator error.
I think it's safe to assume that the transformer is actually a 49:1 ratio.
Thanks!
On Sun, Aug 15, 2021 at 3:48 PM Luciano Luciano <luciano.wdc@...>
wrote:
Hi Charles,
I get "suspicious" when I see small differences like this i.e. 50 ohm as
in this case. Assuming the black box is lossless, you should measure either
2450 or 2500 ohm if you load the other port (with coax connector, right?)
with 50 ohm... if you measure 2450 then it is a 49:1 transformer as you
correctly guessed in the first place! Of course easier to say (and write)
in theory than to actually do in practice.
Regards,
Luciano
On Sun, Aug 15, 2021, 6:15 PM Charles KC6UFM <kc6ufm@...> wrote:
Hello, All...
I recently had a need to measure an unknown matching transformer. As it was
in a sealed enclosure with noth but the wire terminal and coax connector
exposed, and I didn't want to damage the enclosure, I pulled out my trusty
NanoVNA.
All I knew about the "black box" was that it was used with a
10-12-15-17-20m EFHW wire antenna. That made me assume it would be
somewhere in the range of a 49:1 ratio.
I pulled out my decade resistance box and dialed in 2450 ohms (50 ohms x
49) and put that between the output wire terminal and ground. I then
connected the NanoVNA to the coax input.
I then played with the decade box until I got a flat response from the
NanoVNA and the needed resistance to get there was 2501 ohms. Technically,
that makes the matching network about 50:1 ratio.
All of this told me what I wanted to know, but I'm wondering if there would
be an easier, more direct way of getting there with the NanoVNA.
I'm good with the idea that I may have just stumbled onto the right answer
in my madness.
Take Care & 73
--
de KC6UFM
Charles
--
de KC6UFM
Charles
|
Re: Measuring S11 at input of RF power amplifier - could I calibrate "through" an attenuator?
On Sun, Aug 15, 2021 at 02:21 PM, Jim Lux wrote:
What's the ripple in the measurement from? A reduced SNR would give a
random error, not a periodic one, but maybe it's a manifestation of a
phase bias that is contributing more or less depending on the reflected
phase?
The attenuators affect more than S11 SNR when used in this fashion They are not exactly 50 ohms input/output impedance. Also the calibration errors will probably be greater as the DUT impedance is further away from 50 ohms. Roger Roger
|
Roger Need
Vladimir Lebedev
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Donald S Brant Jr