Weirdest thing I've ever experienced in my life

RE: Weirdest thing I've ever experienced in my life

JONATHAN LL — Mon, 09 May 2022 12:39:53 GMT

Hi,

So sorry misunderstanding, I originally though the hex files you shared where the same ones you used.

To keep it short, the reason for the "ghost" packages you are seeing is due to coincidence. When you have a short address the chance of random noise being picked up as a bit.

So to steer clear of the random noise being picked up as a package you have to increase the length, suing base length = 2 is not the best idea.

So the DK it self may be the source of the noise, onboard de-bugger and UART communication seems to be enough to provide enough noise that there is a good chance that something is picked up. Even though there are no other radio signals in the environment.

packet_conf.balen = 2; is the culprit here. Stick to 4, and you should be OK, set balen = 1; and you will see a much quicker increase in ghost packages.

With just the balen = 2 changed from the original radio_test sample there would be something like a chance that every 16 second there is match. With just the noise from the device it self. There are 16 million address combinations and at 1M it is sampling 1 million bit's every second

CRC can help mitigate the issue to some degree.

32-bit address should be minimum.

Regards,
Jonathan

RE: Weirdest thing I've ever experienced in my life

kongstrupp — Mon, 09 May 2022 08:59:40 GMT

Did you download the radio_test sample and mod it exactly like I have described above?

Are you using the nrf52840-DK?

If you receive nothing, try to change the base address to 0x943E and prefix 0x59

RE: Weirdest thing I've ever experienced in my life

JONATHAN LL — Mon, 09 May 2022 06:35:06 GMT

Update: there has been no ghost packages so I think it is safe to assume that the setup you have might be the issue. I would guess either there is something inside the room that advertises packages or it is not properly RF proof.

hope you found a solution to the issue you had.

Regards,
Jonathan

RE: Weirdest thing I've ever experienced in my life

JONATHAN LL — Fri, 06 May 2022 09:18:01 GMT

Hi, Sorry for late reply.

Have not hade any luck replicating the result you have. But I will keep the test going over the weekend and see if there is anything. But I am quite certain that the issue must be related tot he isolation from other RF sources.

Or did you find out what the source of the ghost packets was?

Regards,
Jonathan

RE: Weirdest thing I've ever experienced in my life

kongstrupp — Thu, 21 Apr 2022 10:59:49 GMT

Note, I found this hex file in the radio receiver sample running on IAR EW

RE: Weirdest thing I've ever experienced in my life

kongstrupp — Thu, 21 Apr 2022 10:59:08 GMT

Yes, here is the hex file devzone.nordicsemi.com/.../1411.license.txt devzone.nordicsemi.com/.../receiver_5F00_pca10040.hex devzone.nordicsemi.com/.../receiver_5F00_pca10056.hex

RE: Weirdest thing I've ever experienced in my life

JONATHAN LL — Wed, 20 Apr 2022 14:42:17 GMT

Sorry for the missundersting, was thinking you where trying to upload a picture, my mistake. You are just refencing the pic from the product page.

So you have only a singel USB cable connected to the DK. The DK is in a anechoic chamber/room and there should not be any reason to why you would pick up "ghost" packages.

Can you provide the hex file you flashed on the DK, I want to test with the exact same. Dont have a chamber right away but can test in a RF proof "lunchbox" and see if there is anything showing up. try to replicate your setup. I see you have added the changes in config anc code but want to test with your exat file, just to remove any possible human error in replication.

Regards,
Jonathan

RE: Weirdest thing I've ever experienced in my life

kongstrupp — Wed, 20 Apr 2022 07:46:18 GMT

Well as I said, we do not have picture that would be of any utility. Or am I not understanding you correctly, What do you mean by setup?

What we have is the board, a computer and a wire between it, thats it in terms of "setup" We been using IAR EW with the radio receiver sample, and nrf connect extension for VScode when running the radio_test sample and operating the shell

RE: Weirdest thing I've ever experienced in my life

JONATHAN LL — Tue, 19 Apr 2022 20:52:15 GMT

There does not seem to ba any pictures included, you can click on the insert many and add a picture, or drag and drop in the comment field.

Sorry for the slow response, due to Easter vacation, back to normal staffing now.

Regards,
Jonathan

RE: Weirdest thing I've ever experienced in my life

kongstrupp — Wed, 13 Apr 2022 17:55:58 GMT

1. We are using this board: https://www.nordicsemi.com/Products/Development-hardware/nrf52840-dk which is the nrf52840 DK, we have also tried with this board: www.nordicsemi.com/.../nRF52-DK

2. We are using the antenna that the board provides (internal, no external one).

3. The device is powered via a USB micro cable, (if you look at the picture on the link in 1. we are connecting the board through the upper port).

4. Yes, we used different cables. We actually have two of these boards (two nrf52840), and once we connected one of them to a long micro USB cable It wouldn't turn on again. But yes, we have tried several cables.

5. No, we haven't tried that, we haven't tried soldering to remove the antenna.

6. There is no good picture to show, basically we are in an anechoic room, with our computer and the nrf52840 plugged into it with a micro usb, and that's it.

7. Yes, this behavior appears on other boards aswell the nrf52832 one.

Please let me know if there is any more information that you need.

Best regards

RE: Weirdest thing I've ever experienced in my life

JONATHAN LL — Wed, 13 Apr 2022 15:52:09 GMT

Hi,

If the device is in some sort of anechoic chamber, and you are still picking up packages, wit no other source in the room where the RF signals can come from then that does indeed sound strange.

Are you using custom HW or a DK?

What antenna re you using?

How is the device powered?

If you are running a relay long USB cable, could it be the source of the issue? have you tried a different cable?

If you remove the antenna(remove a dingle series component) does the issue still happen?

Can you share a picture of the setup ?

Does the the software behave the same on other devices?

Due to the Easter holiday there will be a delayed response time, we will be back in full the 19 of April.

This is something we should be able to test, but not until next week.

Regards,
Jonathan