Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- Nanovna-Users
- Messages
Search
Re: Accuracy of calculated values - Nano VNA and Saver
Hi Martin,
I too read Owen's post. I'm not particularly fond of his way of implying that I would be "resistant to correction"; and calling what I do "very hammy". If it is one's intention to post like that, I would consider it normal courtesy to inform the author of the software in question. "Return loss" when shown as a negative value should probably be termed "reflection coefficient". But using the term "return loss" and a negative value has become the norm within at least the hobbyist community. I consider the NanoVNA a hobby device. I might make a "stickler mode" for those who can't look past it ;-) I don't see that he refers to anything I have calculated as being *wrong* - just that he doesn't like the particular things that I have chosen to calculate (equivalent L/C for parallel X, instead of using conductance/admittance). I have put in the readings that have been requested by users. If there are any miscalculations in my software, I do what I can to correct them. I have not recently been made aware of any problems, and at no point by Owen. I hope that any of you would immediately contact me, should you find errors in NanoVNA-Saver! :-) -- Rune / 5Q5R On Fri, 4 Oct 2019 at 14:38, Martin via Groups.Io <martin_ehrenfried= [email protected]> wrote: Hi All, |
Re: Cal-Kit Standards' Definitions
Dr. David Kirkby from Kirkby Microwave Ltd
On Sun, 29 Sep 2019 at 17:40, Jeff Anderson <jca1955@...> wrote:
On Sun, Sep 29, 2019 at 03:43 AM, Dr. David Kirkby from Kirkby MicrowaveAlthough more difficult to implement in the firmware, and a PITA for users, it would not be surprising if even better performance could be obtained by * Setting C0 to 0 * Reading C1 from the datasheet of the cal kit * Adjusting the offset delay from the data in the cal kit, to some longer delay, which would depend on C0. That way only two parameters are entered into the cal kit definitions (a delay and C0). The problem would be every user would need to compute a value for the delay, which would be different for the value in the cal kit. But as an academic exercise - you have convinced me that for the professional calibration kits, used up to 1500 MHz, an offset delay and C0 are fine. Best regards,Dave, G8WRB Dr David Kirkby Ph.D C.Eng MIET Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, Essex, CM3 6DT, United Kingdom. Registered in England and Wales as company number 08914892 Tel 01621-680100 / +44 1621-680100 |
New mode R / L / C display
Hi All,
I've been using my Nano quite extensively in the workshop, and I find it very handy for quickly checking the value of surface mount components, particularly capacitors and inductors. It would be really nice if it was possible to just display the RLC values (and Q ?) in big text (no graph required) for a defined frequency (or frequencies) so it could be used in place of a separate RLC meter, many of which can only measure values at low frequencies <1MHz. What do others think - would this be useful ? Regards, Martin - G8JNJ |
Accuracy of calculated values - Nano VNA and Saver
Hi All,
Owen Duffy has recently posted a note about the Nano VNA on his blog. He makes a few points about the accuracy of calculated values with both the Nano VNA and Saver in particular. If we first deal with the issue of Return Loss, which is probably the most problematic par, and has certainly caught me out on several occasions. Just about every instrument I can remember using, has RL shown as a negative curve, even if the units themselves are positive. This is handy if for example you are tuning a filter, as you can see the insertion gain on the uppermost trace and the RL loss on the lower one without them overlapping. It also matches the convention of SWR plots and when measuring the RL of cables it matches the convention of more attenuation being negative. However Owen makes the point that negative loss is actually gain (double negative) and vice versa, and the existing conventions do indeed lead to confusion and mistakes being made. Maybe return loss should really be called return gain, and then everyone would be happy (well maybe - but this is not a serious suggestion). However if we put this to one side, there is still the issue of how the values are being calculated, and if they are in fact correct. If not then I think this should be investigated in more detail and fixed, as there would seem to be an opportunity to do this before it propagates further. Regards, Martin - G8JNJ |
Re: How many hardware versions?
The block diagram is missing the measurement of the reference signal?
toggle quoted message
Show quoted text
Op 4-10-2019 om 12:31 schreef hwalker: Pluto, |
Re: info update
In your web space I see many files, I need only DMR-CLEAR_MEMORY_DFU.dfu and an executable program, is it correct?
Should I find the program.exe? ..Again: Reasons you might want to upgrade: 1. TDR capability in firmware. -> Can you measure the length of the coaxial cables? 2. Operation up to 1500 MHz (at reduced performance). -> No thanks (ugly dynamic... I imagine)! 3. DFU mode in firmware. -> So at the moment I can't delete the memory with the DMR-CLEAR_MEMORY_DFU.dfu file? 4. Change from 2 trace to 4 trace firmware (or vice versa). -> Better 2 tracks if it slows down with 4...?! With 2 tracks is the "aa" or "ch"? 5. Change to 800 MHz max operation for better device stability -> Interesting. At the moment I have an abnormal peak at 300Mhz on channel S21, maybe it could solve this problem (maybe it's a self oscillation). Thanks.. |
Re: NanoVNA V2
Hello group,
some remarks: On Sun, Sep 29, 2019 at 10:21 AM, Gabriel Tenma White wrote: take a look at Raspberry Pi 3.5" lcds with 480x320 resolution, or bare with ILI9486/ILI9488 controller (a lot of them can be found on chinese shops) * frequency range will go to at least 3.5GHz; PLL limit is 4.4GHz.please consider the MAX2871 which is cheaper than ADF4350 and offers much more than ADI chips at this price (prices compared at Farnell or Digikey - I know chinese clones are far cheaper...) -the footprint and pinout is the same. vy73 Slawek/SP9BSL |
Re: info update
Rob,
Please understand that "DMR-CLEAR_MEMORY_DFU.dfu" will wipe your device and it will not work until you re-load whatever firmware you are upgrading to. It is used to give you a clean slate prior to installing your new firmware. Some users have not been able to upgrade successfully it they do not load "DMR-CLEAR_MEMORY_DFU.dfu" first. All the tools and instructions you need to perform a firmware upgrade are in the links I previously provided. My best advice is that if you are happy with how the nanoVNA is performing to hold off upgrading the firmware until you see a feature or improvement released that you want. Reasons you might want to upgrade: 1. TDR capability in firmware. 2. Operation up to 1500 MHz (at reduced performance). 3. DFU mode in firmware. 4. Change from 2 trace to 4 trace firmware (or vice versa). 5. Change to 800 MHz max operation for better device stability Herb |
Re: How many hardware versions?
Herb,
toggle quoted message
Show quoted text
there appears to be both a "NanoVNA-H V2" and a (completely unrelated) "NanoVNA 2" project. The latter project hasn't been very responsive to questions about who they are, and just seem to have tagged onto the name because of its popularity. -- Rune / 5Q5R On Fri, 4 Oct 2019 at 12:08, hwalker <herbwalker2476@...> wrote:
Pluto, |
Re: Another ebay deal?
On Thu, Oct 3, 2019 at 05:33 PM, Dr. David Kirkby from Kirkby Microwave Ltd wrote:
Or three... Fit a RCA/0.1" pins/BNC/SO239/SMA (depends what freq range and what is to hand) to either side of a pcb and the DUT (Device Under Test) in between. Even less than $6 probably assuming you have the PCB etc. Before comments made about not using SMA yes I 100% understand you are not going to get ?100K kit/lab grade results with a couple old RCA either side of a random bit of PCB, indications probably at best, but then this is a ?50 device in the first place so got to set expectations perhaps? Think I made up and tested 1st HF BPF when and M3 using two RCA (with an expensive VNA) so I know it works, sort of. 72 Dom M1KTA |
to navigate to use esc to dismiss