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On 2/5/22 11:44 AM, Ted Chesley wrote:

Hi Jim, Given that there have been numerous reports of this within the
group, I think that is probably the case. Perhaps the developer or one
of our super users can verify. Maybe a future FW update can extend the
range. In any case 16MB works for me
Regards....Ted

sort of implies that it's not so much that the bigger microSD don't have SPI, it's that the way you use it is different.

So a firmware fix is possible, maybe.

-----------------------------------------From: "Jim Lux"
To: [email protected]
Cc:
Sent: Saturday February 5 2022 11:36:40AM
Subject: Re: [nanovna-users] Cannot Save screenshots to microSD card

On 2/5/22 11:33 AM, Ted Chesley wrote:
> I too had the 32MB issue on my lite VNA. 16MB and below worked
great!
> Still plenty of room considering the average save in NanoVNA-app is
in
> the KB range.
>
> -----------------------------------------From: rseverns@...
> To: [email protected]
> Cc:
> Sent: Saturday February 5 2022 10:23:17AM
> Subject: Re: [nanovna-users] Cannot Save screenshots to microSD
card
>
> I just went through this exercise. I tried a 32GB card but it
> wouldn't work. However, a 16GB card works very well. Rudy N6LF
>
>

Maybe it's 32GB and bigger that have the problem?




Links:
------
[1] /g/nanovna-users/files
[2]
/g/nanovna-users/leave/8706519/4866111/1865567994/xyzzy

Hi Jim, Given that there have been numerous reports of this within the
group, I think that is probably the case. Perhaps the developer or one
of our super users can verify. Maybe a future FW update can extend the
range. In any case 16MB works for me
Regards....Ted

-----------------------------------------From: "Jim Lux"
To: [email protected]
Cc:
Sent: Saturday February 5 2022 11:36:40AM
Subject: Re: [nanovna-users] Cannot Save screenshots to microSD card

On 2/5/22 11:33 AM, Ted Chesley wrote:
> I too had the 32MB issue on my lite VNA. 16MB and below worked
great!
> Still plenty of room considering the average save in NanoVNA-app is
in
> the KB range.
>
> -----------------------------------------From: rseverns@...
> To: [email protected]
> Cc:
> Sent: Saturday February 5 2022 10:23:17AM
> Subject: Re: [nanovna-users] Cannot Save screenshots to microSD
card
>
> I just went through this exercise. I tried a 32GB card but it
> wouldn't work. However, a 16GB card works very well. Rudy N6LF
>
>

Maybe it's 32GB and bigger that have the problem?





Links:
------
[1] /g/nanovna-users/files
[2]
/g/nanovna-users/leave/8706519/4866111/1865567994/xyzzy

I just bought a 16GB microSD card and it work great! Thank you all very much for your help!

On 2/5/22 11:33 AM, Ted Chesley wrote:

I too had the 32MB issue on my lite VNA. 16MB and below worked great!
Still plenty of room considering the average save in NanoVNA-app is in
the KB range.

-----------------------------------------From: rseverns@...
To: [email protected]
Cc:
Sent: Saturday February 5 2022 10:23:17AM
Subject: Re: [nanovna-users] Cannot Save screenshots to microSD card

I just went through this exercise. I tried a 32GB card but it
wouldn't work. However, a 16GB card works very well. Rudy N6LF

Maybe it's 32GB and bigger that have the problem?

I too had the 32MB issue on my lite VNA. 16MB and below worked great!
Still plenty of room considering the average save in NanoVNA-app is in
the KB range.

-----------------------------------------From: rseverns@...
To: [email protected]
Cc:
Sent: Saturday February 5 2022 10:23:17AM
Subject: Re: [nanovna-users] Cannot Save screenshots to microSD card

I just went through this exercise. I tried a 32GB card but it
wouldn't work. However, a 16GB card works very well. Rudy N6LF





Links:
------
[1] /g/nanovna-users/files
[2]
/g/nanovna-users/leave/8706519/4866111/1865567994/xyzzy

I just went through this exercise. I tried a 32GB card but it wouldn't work. However, a 16GB card works very well. Rudy N6LF

Hi,
not for NanoVNA H4, but for my NanoVNA V2 Plus4 I have designed and printed this box.
I have mounted two SMA to N adapters to solve the weakness and the short operating life of the SMA connectors.
The battery is removable without the need to unscrew the adapters.
I have not yet published it on Thingiverse, probably I will make some modifications.

73
Francesco, IN3XZP

On 2/5/22 7:00 AM, alan.eub via groups.io wrote:

I recently got a AURSINC NanoVNA-H with a micro SD card slot and every time I try to save a screen shot it says "FAIL TO WRITE". I am using a SanDisk 64GB microSD card and I can't seem to figure out the problem.

Apparently, the big SD cards don't support the SPI mode interface, which is what the NanoVNA uses.? Stick with 32GB or smaller. (and, given the existence of counterfeit SD cards, it's always good to check it on some other computer).

All of my antennas have a static discharge at the feed point. I would recommend them.

AD5X has a couple of excellent articles on the subject:

<>

<>

Mike N2MS

Here's my solution, I still have to glue the foam down. These are small flight cases3 for ?24.00 on eBay.

However, I wish I had seen your solution first as it is a better and more versatile idea. If I'd seen yours I would have copied it!

Best Wishes - Michael (GW7BBY/GB2MOP)

Of course depending on weather conditions and type of antenna, an antenna can quickly rebuild a static charge after you remove the ground.

73

-Jim
NU0C

On Sat, 5 Feb 2022 08:58:04 +0000
"Michael" <michael@...> wrote:

Yes, grounding the antenna to discharge static before making
measurements is essential, but a protection network will provide
insurance against accidents and errors that can easily occur to the most
methodical of us. NanoVNA/TinySA will be used for work on other devices,
not just antennas. For instance: TinySA for aligning valve radios.

Michael (GW7BBY/Gb2MOP).

On 04/02/2022 20:20, Roy J. Tellason, Sr. wrote:

On Friday 04 February 2022 07:43:31 am Michael wrote:

Search on "How not to damage your NanoVNA when measuring SWR" in
Youtube. Good video basically TVS + Back to Back diodes, series resistor
and good description of functions. Also applies to TinySA.

Michael (GW7BBY/GB2MOP)

Good video, that. I wonder, though, how necessary that protection network is if you make it a point to ground the cable to the antenna to discharge static buildup, and you don't plan to leave the Nano connected?

I just recently read on this group that the max size of SD card is 32 GB so that may be your issue.

73,
Cliff, AE5ZA

I recently got a AURSINC NanoVNA-H with a micro SD card slot and every time I try to save a screen shot it says "FAIL TO WRITE". I am using a SanDisk 64GB microSD card and I can't seem to figure out the problem.

The youtube video is a good one. but I'm really looking for something that has less effect on high frequencies too and can be installed permanently on the nanovna board. I think that TVS diode mentioned by Reinier (ESD101B102ELE6327XTMA1) is the way to go for me. I would prefer if it clamped at 1.5V etc, but 5V perhaps is OK. Mind that I broke my previous Nano with 12V DC only!

The Nano v2 has a 10uF capacitor at ch0. This theoretically blocks DC (not really). I read somewhere it doesn't block DC caused damage because that capacitor is pretty high capacitance (has to be for low frequency response).

I built a simple external limiter similar to one in the video for the time being. This contains two schottky diodes (they will limit to ~0.3V), a 90V gas discharge tube, two 3db attenuators and a 100nF capacitor . I used all Smd parts, shielding, tiny dimensions etc and still it is linear to maybe 20MHz. With careful calibration it can be used for higher frequencies, but it has huge impact on the signal received so it is not ideal.

The mini circuits part is very similar to what I use with my "big boy" SA, but inclusive of shipping and taxes to Europe it becomes pretty expensive for what it is (two pin diodes back to back).

Yep. "Not recommended for new designs" generally means future production and availability is questionable, not that there is any problem with the part's specs or performance.

Hi , if you do the calibration without the assistance , you must do a sweep before "click" on the device .
Maurizio IZ1MDJ

Yes, grounding the antenna to discharge static before making measurements is essential, but a protection network will provide insurance against accidents and errors that can easily occur to the most methodical of us. NanoVNA/TinySA will be used for work on other devices, not just antennas. For instance: TinySA for aligning valve radios.

Michael (GW7BBY/Gb2MOP).

Just a thought, you might want to try the OneofEleven PC program as an alternative to VNASaver.
Using that same program, you can also directly install firmware upgrades to the device.

On 2/4/22 4:26 PM, Ted Chesley wrote:

Hi Jim/Dave, I too have used these mini-circuits limiters, mostly the
ones in a higher range 20/30MHz to 3000 and 6000MHz on commercial SA's
observing multiple 6MHz wide QAM carrier systems with 10 to >100
carriers. Haven't observed any excessive third order IM (IP3). Of
course you have to be aware of the total power produced by the sum of
the carrier powers. Referencing the data sheet (attached) for this
particular limiter, the VSWR is pretty good with highs of 1.44 at
0.2MHz and 1.4 at 3K with mostly less than 1.1 between those
extremities.
The packaging is great, hardly larger that a normal SMA attenuator,
and at $49/ea ordered direct from mini-circuits, it won't break the
bank. Might be a good solution for those who would prefer not to do
surgery on their NanoVNA/TinySA circuit boards.

-

Excellent.. I actually have another use for them at work. Good to know.

Hi Jim/Dave, I too have used these mini-circuits limiters, mostly the
ones in a higher range 20/30MHz to 3000 and 6000MHz on commercial SA's
observing multiple 6MHz wide QAM carrier systems with 10 to >100
carriers. Haven't observed any excessive third order IM (IP3). Of
course you have to be aware of the total power produced by the sum of
the carrier powers. Referencing the data sheet (attached) for this
particular limiter, the VSWR is pretty good with highs of 1.44 at
0.2MHz and 1.4 at 3K with mostly less than 1.1 between those
extremities.
The packaging is great, hardly larger that a normal SMA attenuator,
and at $49/ea ordered direct from mini-circuits, it won't break the
bank. Might be a good solution for those who would prefer not to do
surgery on their NanoVNA/TinySA circuit boards.

-----------------------------------------From: "Jim Lux"
To: [email protected]
Cc:
Sent: Friday February 4 2022 3:50:39PM
Subject: Re: [nanovna-users] Is there a known ch0 input protection
mod? #problem #nanovna

On 2/4/22 2:00 PM, W0LEV wrote:
> Device from MiniCircuits: VLM-33W-2W-S+
>
> URL:
/> >
> Rated from 0.200 through 3000 MHz in a 50-ohm system. It's marketed
as a
> spectrum analyzer protector.
>
> Dave - W?LEV

That looks like the ticket. One thing to check - if you put two
signals
in (with the sum of signals being < limiting threshold) is there any
IMD.

For NanoVNA, which is single frequency at a time, this would be ok,
but
for a spectrum analyzer or receiver protector, maybe not.

I suspect that this has one of the TVS parts we're talking about
inside,
but just in case it's just a diode or something, you want to check.
(It
is sold for protecting SAs, so it's probably not going to introduce
IMD,
but...)

> On Fri, Feb 4, 2022 at 8:19 PM Roy J. Tellason, Sr.
> wrote:
>
>> On Friday 04 February 2022 07:43:31 am Michael wrote:
>>> Search on "How not to damage your NanoVNA when measuring SWR" in
>>> Youtube. Good video basically TVS + Back to Back diodes, series
resistor
>>> and good description of functions. Also applies to TinySA.
>>>
>>> Michael (GW7BBY/GB2MOP)
>> Good video, that. I wonder, though, how necessary that protection
>> network is if you make it a point to ground the cable to the
antenna to
>> discharge static buildup, and you don't plan to leave the Nano
connected?
>>
>>
>> --
>> Member of the toughest, meanest, deadliest, most unrelenting --
and
>> ablest -- form of life in this section of space, a critter that
can
>> be killed but can't be tamed. --Robert A. Heinlein, "The Puppet
Masters"
>> -
>> Information is more dangerous than cannon to a society ruled by
lies.
>> --James
>> M Dakin
>>
>>
>>
>>
>>
>>





Links:
------
[1] /g/nanovna-users/files
[2]
/g/nanovna-users/leave/8706519/4866111/1865567994/xyzzy