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#83 : On the Doubtfulness

Hello,

Allow us, please, to announce that, as it seems, we may just found the deep
source of doubtfulness and in the following way : we thought that we had to
think historically, that is with terms of the time all this measurement adventure
begun, that is with the available accuracy of the calculations -rather than
computations- of that time.

Therefore, also allow us, please, to announce that having already in hand the
last, fully proved, "new" formulation of this "one-port" method of computation
of S-parameters of (reciprocal) two-ports, we focus our next research steps in
this very direction : on the comparison of these "one-port" computation results
with the "classic" one of "two-port" measurement ones.

Sincerely,

gin&pez@arg

:83#

Hugen,
Is there going to be a selectable USB/serial port PC I/O mode for this version with the new uP?
ThanksLarry



On Fri, 13 Dec 2019 at 3:18 AM, hugen@...<hugen@...> wrote: I've made a new PCB for testing, it's working well now, but At the moment ADC1 can't read VBAT data correctly, and I can't get into DFU mode through the menu yet, I haven't found the cause of the problem yet, maybe to fix it after Christmas. Most of the circuits are the same as the current NanoVNA-H, so I don't think this is the next generation of NanoVNA, it's just the NanoVNA that replaced the MCU and has a larger screen, but that's probably the version that many people in this group need. If there are suggestions for changes that can be directly replied to this message, I will improve it.

The attachment is a screenshot.

hugen

Yesterday I received the Nooelec "Balun One Nine V2" and did limited testing. It uses a Coilcraft WB9-1 transformer, with a published 3dB bandwidth of .125-125MHz; interpolating the datasheet graph shows about .5-70MHz at the 1dB points.
I put it on the nano and set span 1-30MHz and calibrated OSL with 450 Ohms as the load.
Then attached 900 ohms and got SWR 2.0; attached 4500 ohms and got SWR 10.0.
I have not yet tested it with reactive loads.
Certainly not a lab-grade test accessory, but may be useful for characterizing parallel transmission lines and high-impedance HF antennas.
--KV5R

From: nanovnauser@...

my post code is ln95je,i put that and it says wrong format every time,tried it in caps too,same result,what should i put then?
==========================================

My account shows the address as "EH10 6**" with "**" replaced by the real postcode.

BTW: I bought a nanoVNA-F which is already cased and with a considerably larger screen. It does make a difference particularly reading the numbers!

Cheers,
David
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

Hi Kurt,

I tried your latest How_to_display_delay_shift_for_a_cable_in_NanoVNA_saver.pdf method.

Now I have many problems. I not understand what I do wrong, or what corrections/calibrations will be required.

See the attacment images. I think my nanovna calibrations not ok. Supplied coaxial cable not symmetrically spiraling inwards to centre smith diagram. Your calibration much better. I try this with different cable, also not good. Teflon dielectic cable, i think better than supplied. I currently not have semi rigid cable to better test. I will get it, but requires lots of time.

I use your method, and your calibration contans.

Now I use latest QRP 4.4 firmware, clearconfig executed, and instrument calibrated with your method.

Formerly, I have good calibrations without trick. It works well, I use many times, working good. But I lost it, I can't reproduce it. I not know why not.

Where from your 0.98 ps? I see on your document marker 1 cursor on 245,025Mhz S11 phase -0,1° so i get 1,134 ps, not 0,98ps. Now, next calculations you use 0,98 and 250, not 245,025.

Fringe C capatince not know how to compute what it causes (more than about clockvise phase shift), and i not know how to measure or compensate manually. Maybe my Hugen-H like calibrators not same? I measured load, only with multimeter. I get 49,9 ohm final value, (subtracted the internal 0,4 ohm error). Not a precise instrumnet, and not 4 leg method, but i think load resistance value good.

I see DG8SAQ WVNA arbitrary calibration formulas to oslt. I not understand this, which value where from. C0 - C3 L0 - L3 Resistance Delays and if exist loss. Many high quality oslt has loss values. I think for amateur instrument more interesting the calibrator loss. I see many cheap connector have much higher loss than precision air dielectric oslt.

So, i cannot convert nanovna values to DG8SAQ WVNA and reverse. Another problem, on wvna original male oslt damaged by other user. Only female oslt in good conditions.

I alsa have some problem on Hugen like load. I see many time contact error. I heard from another nanovna user, his load also problematic. Short, and opens always good. I have there another sma load from used mobile phone system. No data, but i think all of them is good. Contact error never exist. I tried to use these loads for calibrations but i see only minor difference to Hugen like load.

I not know the best method to convert C1-C4 to simple C value.

73,
Lajos

hugen,
The larger display size is great and if the > 50 dB dynamic range to 1500 MHz holds up in the final release then I'd say you have a winner. Does the larger flash_size allow you to increase the measurement points to at least 201? Will firmware developed for the NanoVNA-H be compatible with the F303 based product? Any idea what the target price will be?

- Herb

On Thu, Dec 12, 2019 at 10:28 PM, <nanovnauser@...> wrote:

my post code is ln95je,i put that and it says wrong format every time,tried it in caps too,same result,what should i put then?
======================================================================
Sorry, I assumed you were in the states so my extended zip code comment didn't really apply. I see ln95je is in Horncastle, England. If you haven't already done so you might try using LN9 5JE with a space for the postal code.

- Herb

I've made a new PCB for testing, it's working well now, but At the moment ADC1 can't read VBAT data correctly, and I can't get into DFU mode through the menu yet, I haven't found the cause of the problem yet, maybe to fix it after Christmas. Most of the circuits are the same as the current NanoVNA-H, so I don't think this is the next generation of NanoVNA, it's just the NanoVNA that replaced the MCU and has a larger screen, but that's probably the version that many people in this group need. If there are suggestions for changes that can be directly replied to this message, I will improve it.

The attachment is a screenshot.

hugen

my post code is ln95je,i put that and it says wrong format every time,tried it in caps too,same result,what should i put then?

I have purchased it from them without any hassle, and with complete
tracking online.

On Sat, Nov 16, 2019 at 12:59 PM, Oristo wrote>

A green (not blue) ~US$10 reflection bridge
e.g. from eBay
with matched SMA references (want a matched pair to calibrate nanoVNA CH1)

Oristo,
I picked up a bridge from the eBay link above. The build quality is poor and the 2, 100 ohm resistor pairs are each not in parallel. So even though the board is green, it's no better than one of those blue boards with the same issues.

At least it's fixable.
I've attached a couple of photos.

Hi Herb,
I think Erik or QRP (and maybe Rune) will have to answer that more accurately than me, as what I wrote was my interpretation of their explanation in a forum post waaaay back in October some time.?
... Larry

On Wed, Dec 11, 2019 at 12:46 PM, "[email protected] Notification" <[email protected]> wrote:

* /NanoVNA_Console_Commands_Dec 9-19.pdf ( /g/nanovna-users/files/NanoVNA_Console_Commands_Dec 9-19.pdf )

*Uploaded By:* Larry Rothman <nlroth@...>

*Description:*

This is the latest update of the Console Commands for the NanoVNA as of Dec 9th. It replaces the previous version. updated some command descriptions (per QRP's new v0.4.3 F/W) Please let me know of any errors or omissions.
=========================================================================

I have a question regarding the "sweep" command:

sweep - usage: sweep {start(Hz)} [stop] [points]
if no inputs: then prints current setup eg:300000000 500000000 101
otherwise, can force new sweep settings using the following commands:
start
stop
center
span
cw
set – sets sweep points

Can "sweep" "center" "span" be entered on the same console command line?

<sweep center 30000000> and;
<sweep span 1000000> work for me. But not;
<sweep center 30000000 span 1000000>

TKs

- Herb

On Thu, Dec 12, 2019 at 12:55 PM, <nanovnauser@...> wrote:

,,, i enter my post code,it just says its in the wrong format,ive tried every which way with no luck,im tearing my hair out,anyone any idea whats going wrong? …

====================================================================================

I had an order delayed for a couple of weeks on Aliexpress due to using an extended ZIP+4 code (five digits of the ZIP Code + a hyphen and four digits). As long as the extended zip code has been in use in the U.S. you would think it wouldn't cause any problems, but I had to change to a five digit zip code to complete my order.

- Herb

Hi David,
the NanoVNA-F is designed by a Chinese ham, so what you want to avoid is a
clone - not a Chinese one ;-)

The original NanoVNA-F is available at - and only
there, as I understand. They link to the following seller on AliExpress as
the official shop:

--
Rune / 5Q5R

My FCU refuses to honor charges on my card to Aliexpress. I no longer
tempt ordering from them. Three times. Same results. Likely due to
Chinese vender?

Dave - W?LEV

--

*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*

After using the original with the 2.8" screen, I'm looking to order the
4.3" unit. As best I can gather, there are three units available all with
different external presentations. These are:

1) NANOVNA-F along the bottom right with the Gecko to the right of
the screen on the vertical member.
2) NANOVNA-F along the bottom right with no Gecko.
3) NANOVNA-F along the side to the right of the screen - no Gecko..

I don't want a Chinese clone. Which of these three are legitimate and
worth spending my $$ on? I do NOT want to support the cloners!


*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*

ive found a screen the same as hermans 3.2 inch on aliexpress(thanks for the link herman),however it goes ok trying to buy it untill i enter my post code,it just says its in the wrong format,ive tried every which way with no luck,im tearing my hair out,anyone any idea whats going wrong?,cheers .

Hi,
Like others, I am having problems with Python PyQt5 etc. I am trying to get NanoVNA to run with a Raspberry Pi 4 with very little success. Works perfect on the Mac Pro. Do you or others know of a work around for this excellent program to work on this platform? Any advice would be much appreciated.
73
G8ORE

Garry,

Thanks, I may have formulated unclear but what you state is what I meant.
Uncertainties in M act as "error bars" making it uncertain where you are in the graph, Uncertainties in the calibration standards cause left/right shifts/compression/decompression in the positioning of the graph
--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK