开云体育

I have also seen this. Bad calibration kit.
In my case the 50 ohm load did not connect well to the nut ring, which caused bad calibration.
Order a new one in good quality.

Best
Soren

You can measure a filter without a tracking generator and do want you desire... of course WHY. In any case, sure.

Set your generator to the same level as your vna. Stop the vna sweep so you can do this. Then run the generator direct to the SA. That is your zero reference and then insert filter under test. The measure is now IL and same as magS21.

On Fri, Jan 10, 2020 at 08:54 AM, ejfelix4976 wrote:

Just curious, is there a way to calibrate the output amplitude so that when measuring say a filter I can get it to read the same as a calibrated spectrum analyzer??
===============================================

Ed,
When measuring a filter with a spectrum analyzer the usual procedure is to do so in concert with a tracking generator. The S21 (thru measurement) on the NanoVNA accomplishes the same thing within the limits of its dynamic range.

- Herb

On Fri, Jan 10, 2020 at 08:42 AM, Ken Liao, AA6KL wrote:

" Kudos to Takahashi san for his innovative NanoVNA design and willing to share, to Hugen for his meticulous effort to drive down the cost and improve performance, and to everyone for your supports and suggestions. "

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

Ken,
Thanks for the comprehensive rundown of the additional features. Also, don't forget to take a bow yourself for spearheading the larger screen size effort. As a fellow enthusiast, I will be following your involvement in this and whatever other projects you plan in the future.

- Herb

Hi everyone,
Just curious, is there a way to calibrate the output amplitude so that when measuring say a filter I can get it to read the same as a calibrated spectrum analyzer??
Thanks,
Ed

I am glad that Hugen finally decides to release the NanoVNA H4 product, based on F303 and 4" LCD. He kept improving the design that I didn't know when he would be satisfied. Besides these two main features, there are some other improvements.

- RF front-end circuit on noise and sensitivity improvement.
- Power management circuit.
- Larger battery capacity.
- UART and two other GPIO pins are brought out to allow for Bluetooth, BLE, or any other connections.
- Jog switch sensitivity.
- Enter DFU by pressing down the jog switch at power-on. The LCD screen will be black at DFU mode. We have to do so since the software jump to DFU mode doesn't work for F303.

Initially, I was thinking of using NanoVNA to learn ChibiOS, but I disliked the flash size of STM32F072. So I contacted Hugen to discuss the possibility of replacing F072 with larger MCU, and invited him to join this forum. Here, Hugen received lots of feedback from the community. So he decided to make the F303 based NanoVNA with larger LCD. We contacted the NanoVNA's original author Takahashi san (edy555), who is an enthusiast in promoting RF engineering. He gave Hugen some advices. Currently he is planning a new project. Maybe it's another VNA covering higher frequency and better sensitivity, or maybe another useful tool. We will know soon.

For this project, I worked on the software porting to F303, used ChibiOS's ADC API for touchscreen, and ported the LCD display controller to ST7796S to support 320x480 4" LCD. Hugen carefully verified my codes and fixed some GUI issue and used larger fonts. He also incorporated some improvements and suggestions from GitHub users, including edy555, cho45, qrp73, Pmax65, etc.

The NanoVNA-H4 and NanoVNA-F took different approaches to provide larger screen. NanoVNA-F is an excellent product with larger, bright and high resolution LCD, larger battery, metal case, and is FreeRTOS based; while Hugen and I think that keep price low and continue to use software based on original NanoVNA code could better promote community involvement.

There are still places to be improved, such as the touchscreen responsiveness. Hugen and I will post firmwareupdate if we have any fix.

Kudos to Takahashi san for his innovative NanoVNA design and willing to share, to Hugen for his meticulous effort to drive down the cost and improve performance, and to everyone for your supports and suggestions.

73
Ken Liao, AA6KL

On Fri, Jan 10, 2020 at 08:37 AM, Dick wrote:

Is this model the one with the Big screen or the Little screen ?
=======================================

Dick,
Current model has 2.8" screen. This model has 4" LCD. See previous messages for other differences (larger battery, etc.).

- Herb

Is this model the one with the Big screen or the Little screen ?

Thanks, Dick, W1KSZ
________________________________
From: [email protected] <[email protected]> on behalf of hwalker <herbwalker2476@...>
Sent: Friday, January 10, 2020 9:27 AM
To: [email protected] <[email protected]>
Subject: Re: [nanovna-users] We started selling nanoVNA-H4 using STM32F303CCT6 and 4-inch LCD

When I try that using Firefox, I get a blank white window after hitting "Send inquiry now" and, yes, I checked the agree with Alibaba box
==============================================

Glen,
On the right hand side of the page there should be an area that allows you to start a chat with Maggie King for Paypal purchases. You generally have to check back for a reply in a few hours after sending your request because of the time zone differences.

- Herb

On Tue, Jan 7, 2020 at 02:26 AM, Gabriel Tenma White wrote:

Because of popular demand we replaced the jog switch with buttons
=====================================================

Gabriel,
Have you noticed any detuning effects from hand capacitance by having the buttons in such close proximity to the connectors? The selection of buttons over the jog switch should make the unit more durable, especially for heavy handed users.

Happy to see that you have added the python branch to your GitHub repository.

- Herb

When I try that using Firefox, I get a blank white window after hitting "Send inquiry now" and, yes, I checked the agree with Alibaba box
==============================================

Glen,
On the right hand side of the page there should be an area that allows you to start a chat with Maggie King for Paypal purchases. You generally have to check back for a reply in a few hours after sending your request because of the time zone differences.

- Herb

Where can I get better manual or instructions?

Whats the total cost in gbp for sending 1 unit to the uk,ie vna inc shipping?

When I try that using Firefox, I get a blank white window after hitting "Send inquiry now"

and, yes, I checked the agree with Alibaba box

73

Glen K4KV

On Fri, Jan 10, 2020 at 10:52 PM, @ColinDexter wrote:

It seems that the more often I calibrate, the worse it gets. It also no longer
indicates a short circuit :-(
I have attached the picture ope, short and load

Although this is not the version I made, I am happy to remind you that you can view the correct data by simply switching the blue curve to CH0. The picture shows that the clone manufacturer uses very old firmware, and it is strongly recommended that you update the firmware to the latest version.

hugen

Colin,
These are with calibration active, can you go in the calibration menu and switch of the calibration so we can see the raw measurements?
This will help understand where the problem is

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK

It seems that the more often I calibrate, the worse it gets. It also no longer indicates a short circuit :-(
I have attached the picture ope, short and load

W6LG just posted a video measuring coax loss using nanovna and -saver:

His measurements were pretty close to the coax loss calc on my site :-)
--kv5r

On Fri, Jan 10, 2020 at 09:32 PM, hwalker wrote:

Notable changes:

RF output @ 0dbm (±2dbm) is higher than previous version


- Herb

NanoVNA-H rev3.4 has been similarly modified, please check


hugen