开云体育

As this ("deal on ebay") has been a recurring theme for some time (these sorts of offers happen on other items, nanovna is one of the subject items for this sort of spam/scam), I would like to suggest the following:

The majority of these non-delivery "deals" arise from misuse of an existing ebay account. If you purchase from one of these listings, you can (and very much should) seek a refund from ebay after the delivery time passes with no delivery.

Almost all of these listings share common characteristics - abnormal buy-it-now pricing (<USD 25), few seller feedbacks (<100, sometimes very few with private or hidden details), no other related items listed (i.e., other items that don't seem to be rf electronics), and no evidence of feedback for sale/delivery of the nanovna. Be sure you're looking at a listing for the nanovna proper (there are numerous multi-item listings that show a price range and might initially look faulty but are not necessarily so.)

Any ebay user can click "report item" link (navigation for US version users is this, other languages may vary --- right side, part way down the screen to the right of "shipping and payments", you may need to scroll down to find it, as it's a simple text link and not very easy to see). Click on "report item" (then you may need to re-supply your ebay password), then choose report category = "listing practices", then choose from reason for report = "fraudulent listing activities", then choose from detailed description = "you suspect that a listing is fraudulent". Finally, click submit report. ebay usually will remove these listings sooner than might otherwise be the case. Doing this properly may help reduce the preponderance of these dead-end listings.

Thank you for your interest in and support of nanovna-users,

Dave

A firmware upgrade for the NanoVNA was just announced by edy555:

"Just released ,NanoVNA firmware 0.5.1 , add marker function 'group delay to electrical delay"

Hard to translate the Japanese description, but I believe it allows the electrical delay values to be changed by dragging the marker - in addition to using the onscreen keyboard.

- Herb

Of course. Port extension not ideal. Simplest method only compensated the electrical lenght. More advenced method use simple frequency depend loss model. Best the complex model.



With nanovna + zplots possibly caracterize unkown coax parameters.

Hi David,

Maybe because members of the group have disclosed the information to the group - if you are interested, you have to log in. This is the case elsewhere.
The -F group is another group, if you have a problem with them, ask for another group.

Regards, Gyula HA3HZ

Hi Sam,

Take care with port extension. At low freq you can get away with it without much error. However, as you go to higher freq, it can really mess things up.

Better off knowing what the fixture parasitic looks like and use proper de embedding arithmetic to "move the measure" plane.

Alan

Has anyone considered using TNC connectors? Not as heavy as N Types and, according to Amphenol, good from DC to 10 Gig.

Paul

On Wed, Nov 20, 2019 at 10:11 AM, Larry Rothman wrote:

Please DO NOT USE any LiIon battery that is beginning to swell !!!? Recycle it.Once a LiIon battery is starting to swell, its internal chemistry is unstable.

Larry,
While I appreciate your abundance of caution, I have observed that these flat batteries "just begin" to swell almost immediately (i.e., a fraction of a mm and they will spin on the desk) after only a few cycles, and they continue to slowly expand throughout their useful lives (2-3 years), until they will no longer fit in the phone and the back cover cannot be snapped in place -- and none of them have ever gone exothermic. At that point I discard them in my 55-gallon burn barrel with the trash, and burn them up, without noticeable incident.
I think it's likely that the rare ones that do go exothermic have faulty protection circuits, or careless re-purposing; hence my question about the 2 additional terminals.
Thanks for the Instructables article; it's good to know the contacts can be soldered without ruining the battery.
73, --kv5r

I agree with David. I bought a Nano VNA which is very good for the money but my eyes are not good enough for it to be of any use as a portable instrument so I immediately ordered a NanoVNA-F purely for the larger screen. The NanoVNA is now primarily used with the PC.

73

Conrad PA5Y

________________________________
From: [email protected] <[email protected]> on behalf of Dr. David Kirkby, Kirkby Microwave Ltd via Groups.Io <drkirkby@...>
Sent: 22 November 2019 17:30
To: [email protected] <[email protected]>
Subject: Re: [nanovna-users] F303 and 4" LCD for next generation NanoVNA #circuit #flash_size #improvement #enclosure #battery

On Fri, 22 Nov 2019 at 15:32, David J Taylor via Groups.Io <gm8arv=
[email protected]> wrote:

For me, having the extra resolution of the 4.3-inch display would be a
significant benefit, and the extra size would not be unwelcome. More than
101 points per plot would be possible. The increased weight would be more
than offset by increased usage time. We already see some of these
advantages in the NanoVNA-F.

73,
David GM8ARV

I agree with David - weight is not an issue.

I think if Hugen wants to sell these in a reasonable quantity, I think the
screen will need to be at least as big as the NanoVNA-F, as I think many
people will buy the NanoVNA-F for a better screen.


Dave.
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

On Fri, 22 Nov 2019 at 15:32, David J Taylor via Groups.Io <gm8arv=
[email protected]> wrote:

For me, having the extra resolution of the 4.3-inch display would be a
significant benefit, and the extra size would not be unwelcome. More than
101 points per plot would be possible. The increased weight would be more
than offset by increased usage time. We already see some of these
advantages in the NanoVNA-F.

73,
David GM8ARV

I agree with David - weight is not an issue.

I think if Hugen wants to sell these in a reasonable quantity, I think the
screen will need to be at least as big as the NanoVNA-F, as I think many
people will buy the NanoVNA-F for a better screen.


Dave.
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

Thanks for the info

A few thoughts:
EN for the ble module could be useful to shut it down as much as possible to lower the noise, or should we cut off its VCC in this case a p-chan mosfet on the VCC line could do.

If 2 batteries, then a boost converter could be used for charging them from the 5v. Boost converter is a mosfet, diode, coil, can be driven by the stm32 and monitored as well by the stm32 using an adc input.

Regards
Jose

On Fri, 22 Nov 2019 at 15:11, Ken Liao, AA6KL <kuohsing@...> wrote:

Regarding the display size, NanoVNA-F's 4.3" IPS LCD is a nice one. But
it comes at the cost of price, large battery, and extra weight. Also, its
800x480 resolution requires parallel interface to reach sub-second refresh
rate. That's why NanoVNA-F uses 100-pin STM32F103VET6. Another type of
4.3" LCD has 480x270 resolution with parallel interface only. ILI9488 only
supports 24-bit RGB at SPI interface, and ILI9486 is reaching end of
production. So it seems that this ST7796S based 4" LCD is the best choice
in term of price, weight, performance, and availability. Hugen has
installed a FFC connector at the prototype, so it should be easy to replace
the LCD if desired.

What is the resolution of the 4” display you intend using? Is it less than
the the NanoVNA-F? If so, I would not buy one.

The NanoVNA-F comes with a 5600 mA hr battery, which I believe will run the
unit for about 18 hours. It is not that expensive.

Screen size is the biggest problem for me with the NanoVNA, so I am willing
to pay extra for a better screen.

For the SMA or N-type socket, it's better to have IPX/IPEX/UFL sockets on

PCB, and screw the SMA or N-type sockets at the case. This will help
prevent the PCB get damaged from screw/unscrew connectors. Then, the
female N-type center pin height issue mentioned by Dr. David Kirkby can be
solved too.

No, the problem I mentioned can *not* be solved by that. The problem is
that the centre pin of a female N sticks about 5 mm in front of the
reference plane. This is in the standard for an N connector - it is 0.207”,
which is just over 5 mm. So if you leave a female N connector open, it will
not have a zero phase angle.

I just calibrated an 8753ES which has adapters to female N. I then removed
everything from the female N connector. I attach a Smith Chart view as
well as a phase plot. One can see that at 1.5 GHz, the phase is -20.162
degrees. So if you assume that an open female has a phase of 0 degrees,
there will be significant error. Probably around 12 degrees at 900 MHz.

Any male short standard would be nothing like 180 degrees. So the lack of a
properly implemented calibration routine would cause *very significant
errors* with the N connector.

The jog switch is a difficult one. Edy555 uses GPIO interrupt and
software debounce already. I replaced job switch's pull-up resistor from
10K ohm to 1K ohm. It seems to respond better, although not perfect yet.
If the pins are exposed, we could either connect to external buttons or
rotary encoder.

That sounds good.

Regarding the power supply, I would hope to have a way to bypass the
voltage pump circuit and use external 5V power supply when quiet power is
needed.

About the BLE support, besides the VCC, GND, RX, and TX, do we also need
other pins like SELECT, STATE and EN?

Ken

Dave

--

Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

I would like to see the archives, files and Wiki open, so that it may encourage others to join the group after seeing the available material. Why block information which members have freely contributed for the communal benefit?

I'd like to see the same for the nanoVNA-users group too.

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

Thanks Hugen's correction. And special thanks to Oristo8 and Larry for maintaining the wiki pages for us to quickly look for useful information.

Regarding the display size, NanoVNA-F's 4.3" IPS LCD is a nice one. But it comes at the cost of price, large battery, and extra weight. Also, its 800x480 resolution requires parallel interface to reach sub-second refresh rate. That's why NanoVNA-F uses 100-pin STM32F103VET6. Another type of 4.3" LCD has 480x270 resolution with parallel interface only. ILI9488 only supports 24-bit RGB at SPI interface, and ILI9486 is reaching end of production. So it seems that this ST7796S based 4" LCD is the best choice in term of price, weight, performance, and availability. Hugen has installed a FFC connector at the prototype, so it should be easy to replace the LCD if desired.

The LCD back light is driven by a DAC pin and a NPN BJT. So it should easy to add firmware support to control back light later.

For the SMA or N-type socket, it's better to have IPX/IPEX/UFL sockets on PCB, and screw the SMA or N-type sockets at the case. This will help prevent the PCB get damaged from screw/unscrew connectors. Then, the female N-type center pin height issue mentioned by Dr. David Kirkby can be solved too.

The jog switch is a difficult one. Edy555 uses GPIO interrupt and software debounce already. I replaced job switch's pull-up resistor from 10K ohm to 1K ohm. It seems to respond better, although not perfect yet. If the pins are exposed, we could either connect to external buttons or rotary encoder.

Regarding the power supply, I would hope to have a way to bypass the voltage pump circuit and use external 5V power supply when quiet power is needed.

About the BLE support, besides the VCC, GND, RX, and TX, do we also need other pins like SELECT, STATE and EN?

Ken

Ditto. Would have been a 2nd one for hacking in the workshop, didn't look right and might not work but for spares was almost too cheap to ignore. Anyway ebay/paypal buyer protection works so it isn't a bad option to use.

"We've issued a refund of US $20.99 back to the original funding source you used to purchase this item. The refund includes the purchase price plus original shipping. Please allow 48 hours for it to process"

The seller looks like they had > 60% negative comments in last month so set feedback private.

72

Dom
M1KTA

On Fri, Nov 22, 2019 at 12:06 AM, Dr. David Kirkby, Kirkby Microwave Ltd wrote:

- STM32F303CCT6, which has 128KB flash memory, 40KB SRAM, and 8KB CCM,

Correct, STM32F303CCT6 has 256KB FLASH.

hugen

Thanks, that sound like one I should try. I will order one and do a review on my show. Do you mind if I mentioned that you help me find one?

Tom

Interesting and thanks for the info.

Tom

Thanks for the info. This one does not appear to come with a case. There are so many similar ones that have bad reviews. This particular has no reviews. Thanks for your time.

Tom

On Thu, Nov 21, 2019 at 04:56 AM, Dr. David Kirkby, Kirkby Microwave Ltd wrote:

Thnx, dear 9 lined signature sales man.

On Mon, 18 Nov 2019 at 13:58, RFy <gpdxdveil@...> wrote:

450mAh is... Not suitable for NanoVNA
1. Stand-by draw
2. Charge circuit pushes over 1A( over 2C rate )

My battery already swelled( PCB/LCD curved slightly )

There are some high specification batteries for sale on eBay, at quite a
reasonable cost.




Dave.
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom