Yes, I want to screw a 4-inch display to my V2, I can¡¯t see anything on the small display!
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On Sat, May 23, 2020 at 12:39 PM, <aleks07111971@...> wrote:
Hi, will you screw the 4 inch V2 display?
It will be available later and a structure must be made that can support a 4" LCD.
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Hi, will you screw the 4 inch V2 display?
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Thank you all so much for your help so far!
I've taken the cable down to analyze it. I removed all adaptors and intermediate cables as Allison suggested. Using the lambda/8 method suggested by Jose, I get an impedance of 54.1 ohms. I have also found the open circuit impedance at lambda/4 and lambda/2, which should average out to the characteristic, and gives me 53.2 ohms, so it looks like the cable impedance is somewhere around 53.6 ohms. I'm not sure if this is within usual tolerance, but it seems questionable for such expensive cable.
My antenna is definitely not matched. (I got the vna to design a matching network). As the blog post shared by John points out, properly matched coax should not cause the ripples that I see. It should cause a frequency-dependent phase shift in the impedance, but not affect the magnitude/SWR. So it seems the ripples are likely caused by the mismatch between the cable and vna, and greatly increased in magnitude by the mismatch between the cable and antenna.
So it looks like these SWR ripples can be explained without any problem with the calibration or vna. However, if anyone has suggestions for verifying the output impedance of my nanovna, I'd still like to do it!
Thanks again!
Ed
KC1DKY
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Re: NanoVNA firmvare, compiled by DiSlord
#firmware
DiSlord, This absolutely fantastic!? How much free flash is left over now for other enhancements? As for the card detect switch, can you use one of the spare pins on the uP as a sense input from the card slot switch? That way, you can verify quickly if a card is present.? Please add the code to your GitHub repo (if not there already) as I would like to see how you implemented this.? Thanks! Larry On Fri, 22 May 2020 at 6:12 PM, DiSlord<dislordlive@...> wrote: Preliminary alfa update for NanoVNA H4 v0.9.0 As you know H4 have SD Card support (see images), but MicroSD slot not installed on board I install it (get from old card reader), and implement read/write functional. SC card Read/Write use: SPI bus (shared vs LCD display), not decrease SPI bus speed, on test card not big amount errors on this speed
For read operation use CRC16 check, for not lost data
For write operation use multiple repeat on write errors
Supported cards: SD v1, SD v2, MMC (check only SD v2)
SD card slot pin CD not connected (it used for define inserted card in slot), so on every write need check it (it slowdown speed). SD card use SPI bus for read/write operations (not fast speed, but easy to add), Stm32f303 processor not have hardware support SDIO :( For filesystem support use last FatFS R0.14, options: Support Fat16/Fat32 filesystem
Support long filenames
Support RTC use (real time clock)
Support read/write file For take screenshot need click on Bandwidth text on bottom (see screenshot) For get and write 1 screenshot need ~2-3 seconds (filesize ~300kB), output format 16bpp *.bmp If screenshot success on middle screen show SCREENSHOT
VNA_20200522_86284.bmp or in some cases (i can`t find how check CRC on write operations) SCREENSHOT
? Fail write All screenshots put in root directory, filename format: VNA_year mounth day_number.bmp For support time in Fat filesystem and filename, implemented RTC clock in VNA For set clock need use command 'time' usage: time [y|m|d|h|min|sec] value Warning! command time not check correct value input RTC clock not reset while battery in All logs go to console, so possible see some errors (connect to PC, run Putty or another console programm and made some screenshots) Warning!!!! For not lost data, not use card vs important data, use formatted on Fat32 filesystem cards. PS support SD card take 2 days, but now i know how it work :) (read a lot of manuals and datasheet)
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Re: NanoVNA firmvare, compiled by DiSlord
#firmware
Here additional foto.
At the place where the card slot is located, a hole was cut. Now the card can be removed and put without any problems.
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Re: NanoVNA firmvare, compiled by DiSlord
#firmware
Preliminary alfa update for NanoVNA H4 v0.9.0 As you know H4 have SD Card support (see images), but MicroSD slot not installed on board I install it (get from old card reader), and implement read/write functional. SC card Read/Write use: SPI bus (shared vs LCD display), not decrease SPI bus speed, on test card not big amount errors on this speed
For read operation use CRC16 check, for not lost data
For write operation use multiple repeat on write errors
Supported cards: SD v1, SD v2, MMC (check only SD v2)
SD card slot pin CD not connected (it used for define inserted card in slot), so on every write need check it (it slowdown speed). SD card use SPI bus for read/write operations (not fast speed, but easy to add), Stm32f303 processor not have hardware support SDIO :( For filesystem support use last FatFS R0.14, options: Support Fat16/Fat32 filesystem
Support long filenames
Support RTC use (real time clock)
Support read/write file For take screenshot need click on Bandwidth text on bottom (see screenshot) For get and write 1 screenshot need ~2-3 seconds (filesize ~300kB), output format 16bpp *.bmp If screenshot success on middle screen show SCREENSHOT
VNA_20200522_86284.bmp or in some cases (i can`t find how check CRC on write operations) SCREENSHOT
Fail write All screenshots put in root directory, filename format: VNA_year mounth day_number.bmp For support time in Fat filesystem and filename, implemented RTC clock in VNA For set clock need use command 'time' usage: time [y|m|d|h|min|sec] value Warning! command time not check correct value input RTC clock not reset while battery in All logs go to console, so possible see some errors (connect to PC, run Putty or another console programm and made some screenshots) Warning!!!! For not lost data, not use card vs important data, use formatted on Fat32 filesystem cards. PS support SD card take 2 days, but now i know how it work :) (read a lot of manuals and datasheet)
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I did not see it as mocking, but rather a brilliant and feasible
explanation of what might be the cause of the VSWR 'ripple'.
toggle quoted message
Show quoted text
On Sat, 23 May 2020, 04:21 John AE5X, <ae5x@...> wrote: Another opinion is offered here, along with a bit of mocking of you
"online experts" - his words, not mine:
--
John AE5X
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Re: Are any of the NanoVNA sold on Amazon any better or worse than any others? Is there a better U.S. site to order from?
I received the 25 dollar unit from Amazon today.
It is the gen111.taobao.com unit. I looked at that web site and it is a Chinese NanoVNA store.
This one defaults to 50KHz to 900 MHz at power-up.
Hans was correct: the open and short calibrators were screwed onto the unit and the 50
ohm calibrator was screwed onto one of the two included cables with a fem-to-fem adaptor.
It's all good. It has a plastic storage case that everything just fits in.
The lcd screen is a little misaligned, not square with the cutout, but not a problem. It is only off by a minor amount
and doesn't affect readability.
I am thoroughly happy with it.
I have to wear my magnifier glasses to read it.
I will probably get the 4.3 inch screen version in the future.
73 de N8MIB, Mike
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Re: Looking for firmware with battery indicator, 1500 and big font
On Fri, May 22, 2020 at 04:07 PM, Birdman wrote:
KV5,
That sounds fantastic! I had a hard time following what version of firmware
does this, and where is the "Ch-0 Info" screen? I don't recall seeing that
option when I tried the big font software a few weeks ago.
Thanks in advance....!
--
Regards,
Chris
Disregard, just reloaded the big font and found it under "Config". I missed that the last time I tried it. Love this functionality: Select a marker on SWR, and then use the scroll clicker to move around and find the best SWR values, without the use of a microscope!! @Hugen, you really should make this functionality part of your standard firmware!! There are certainly a lot of folks asking/discussing this subject.... And if nothing else, the larger fonts are really helpful. I can barely read the tiny little normal fonts WITH my reading glasses on, at my desk. I can only image somebody trying to use this out in the "field". -- Regards, Chris
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Re: Looking for firmware with battery indicator, 1500 and big font
On Sun, Nov 10, 2019 at 01:33 AM, KV5R wrote: Also, noted that the "Ch-0 Info" screen works even if all traces are off
(reduces clutter) and freq is CW, so it works like a text-based antenna
analyzer and is very easy to read, with those 5mm high digits! And with only
SWR trace on, and a small span, the jog switch will move the frequency in
small steps, and Marker > Search > Minimum will find lowest SWR point in the
swept span.
I'm sure these added features will make the nano more attractive to hams with
primary interest being antenna analyzer. KV5, That sounds fantastic! I had a hard time following what version of firmware does this, and where is the "Ch-0 Info" screen? I don't recall seeing that option when I tried the big font software a few weeks ago. Thanks in advance....! -- Regards, Chris
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Please refer to the user guides in the files sections and the notes in the wiki.
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On Friday, May 22, 2020, 3:46:27 p.m. GMT-4, J72IMS Ishmael Samuel <ishmaelsamuel79@...> wrote:
how do i calibrate the nano vna and how do i use the usb b type cable
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how do i calibrate the nano vna and how do i use the usb b type cable
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Another opinion is offered here, along with a bit of mocking of you "online experts" - his words, not mine:
--
John AE5X
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I don't understand this TXCO error concern. Is the NanoVNA being used as a precision freq counter?
If you are using it for measurements between 2 freqs, what is the % of precision you are expecting from an instrument that costs less than $100.00 USD? Most test equipment is ¡À3%. I believe these are well within that.
?___
Sent from my two way wrist watch
73 de W3AB/GEO?
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On May 22, 2020, 10:27, at 10:27, Rudolf Schaffer <rudolf.schaffer@...> wrote: Hi Mike,
I agree totally ! It would be very useful in my case, waiting to
replace
the TCXO.
For the moment, i'm obliged to multiply the desired frequency by
1.0000855 to compensate
the too large error of the TCXO.
73 QRO,
Rudi, HB9ARI
Le 22.05.2020 ¨¤ 17:38, vbifyz a ¨¦crit?:
It would be nice to have a menu option to calibrate the frequency. It is easy to adjust the Si5351A output frequency, all libraries for it
include this function.
73, Mike AF7KR
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Hi Mike,
I agree totally ! It would be very useful in my case, waiting to replace the TCXO.
For the moment, i'm obliged to multiply the desired frequency by 1.0000855 to compensate
the too large error of the TCXO.
73 QRO,
Rudi, HB9ARI
toggle quoted message
Show quoted text
Le 22.05.2020 ¨¤ 17:38, vbifyz a ¨¦crit?: It would be nice to have a menu option to calibrate the frequency. It is easy to adjust the Si5351A output frequency, all libraries for it include this function.
73, Mike AF7KR
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RES: [nanovna-users] Trouble buying from China
Joao Carlos de Carli - IU5JCI
I bought mine last may 14h from this seller and DHL expects to deliver in Italy next may 27th. Regards, 73 de Joao, IU5JCI -----Mensagem original----- De: [email protected] [mailto: [email protected]] Em nome de Leif M Enviada em: venerd¨¬ 22 maggio 2020 19:13 Para: [email protected]Assunto: Re: [nanovna-users] Trouble buying from China I got mine today and I bought it around Apr 14. I live in Finland. Mail between Europe and China is currently not working IMO.
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On 20/05/2020 20:00, Bob Solimeno wrote: I've been able to install the NanoVNA-Saver on Ubuntu 20.04 using the attached helper document. I regret to say that I forgot where I found it ... memory loss is the first sign of senility!
The nice thing about this approach is that it can be set up with a script, saved as a desktop icon and run easily. One caveat is that your username must be part of the"dialout" group on your Linux system so that access to the usb port will be allowed to connect the NanoVNA to your computer. As always, your mileage may vary if running other versions of Ubuntu or other distros.
73 Bob KC2JAV
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Re: Trouble buying from China
I got mine today and I bought it around Apr 14. I live in Finland.
Mail between Europe and China is currently not working IMO.
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As previously stated, you're fine. What you are seeing is quite expected.
Take your cal standard of 51 ohms: Assuming your cal standard is truly is
51.0000000 ohms (DMM measurement tolerance), the SWR against
50.000000...... ohms would be 51.0000000 / 50.000000, or 1.020:1. I doubt
any amateur SWR meter would display this as anything other than 1:1.
Again, not a problem.
Take your coax: Try making an identical measurement with the antenna end
of the line terminated with your 50-ohm cal. load or another known good
resistor (connect with no leads and the resistor must be good at 146 MHz -
no series reactance) in place of the antenna. The ripple is likely due to
your antenna not being 50.000..... ohms over the entire bandwidth you are
measuring. Again, this is quite typical and not a problem.
Dave - W?LEV
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On Thu, May 21, 2020 at 3:15 PM Kurt Poulsen <kurt@...> wrote: Hi Ed
It is quite normal what you see. Please note that the number of point are
only 100 so for the span used 50MHz you have a point for each 0.5MHz.
Reduce the span to e.g. 140 to 150 MHz and see for every 100KHz the
impedance / SWR. The load are OK it is not what you concern should be, It
do not think you Ohm meter are accurate enough to determine the very exact
DC resistance and will only create a very little SWR contribution.
I would guess you antenna does not have 50ohm impedance on 145MHz. The
oscillation you see are natural for reflection from the antenna which is
wandering forth and back in the cable.
Kind regards
Kurt
-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af
ed@...
Sendt: 21. maj 2020 07:35
Til: [email protected]
Emne: [nanovna-users] Calibration issue causing ripples in SWR?
#calibration
After calibrating, I connected my nanovna to my VHF antenna via a brand
new 75 foot length of 50ohm DX400MAX coax. The SWR measurement oscillates
up and down every 4MHz or so (see attached). These correspond exactly to
the half-wavelength harmonics of the cable. Looking at the smith chart, it
is clear that the impedance is tracing a circle around about 45 ohms rather
than the constant-SWR circle centered at 50 ohms, resulting in a
frequency-dependent SWR.
Is there is a good way to determine whether this is a problem with my
nanovna, with the calibration standard, or with the cable?
One note: the calibration standard load measures 51 ohms DC resistance,
which seems like a problem to me. Should my standard be exactly 50 ohms dc
resistance?
--
*Dave - W?LEV*
*Just Let Darwin Work*
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Chris K2STP
GEO BADGER