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svpcom / wfb-ng

WFB-NG - the next generation of long-range packet radio link based on raw WiFi radio
https://docs.px4.io/main/en/tutorials/video_streaming_wifi_broadcast.html
GNU General Public License v3.0
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`RTL8812BU` Launch Report #381

Open MuratovAS opened 2 weeks ago

MuratovAS commented 2 weeks ago

Initial conditions:

Result: After a series of trials and errors I managed to achieve operability on the RTL8812BU chip. The system works in two ranges, 2.4Ghz and 5Ghz.

I checked the functionality with the rtw88_8822bu driver built into the kernel. With default settings the system refused to work, data is not sent or received. After I changed the line to frame_type = 'rts', the connection worked, but the transfer speed was unacceptably low, about 50Kb/s.

I was able to achieve stable operation using a custom kernel module from RinCat. Using this code, the connection speed through the tunnel was about 8Mb/s. On standard wfb-ng settings.

Based on the data I received, the chip can be used. As soon as I have more data, I will let you know here.

svpcom commented 2 weeks ago

@MuratovAS Thanks!

P.S. I've seen your portfolio - could you advice dc-dc for powering such wifi cards? Most of powerful 8812au and 8812eu cards consume > 3A in pulse when transmitting and generic dc-dc converters from aliexpress requires additional low-esr capacitors to survive these pulses. Are any better (an cheap) solution to power such cards from 3S-6S batteries?

MuratovAS commented 2 weeks ago

I would advise:

I would build a converter on RT6365, simple, reliable, cheap, powerful. If you need a ready-made solution URB2405LD-20WR3 or URB2405LD-30WR3

svpcom commented 2 weeks ago

@MuratovAS Thanks! I had very bad experience with this dc-dc: image

It dies with smoke when connected to 24V and connection is unreliable: https://t.me/wfb_ng/4457/11336

svpcom commented 2 weeks ago

@MuratovAS Do you have any idea why glitching of input voltage can lead to dc-dc burnout? It is IC design flaw or bad schematics? All three dc-dc in my test dies identically: fail case near +Vin pin was burn out

voanhcuoc commented 2 weeks ago

Thanks to this report, I've conducted an experiment:

I don't have a DSI monitor for Pi, so I connected an Android phone with the Pi by a USB cable. Then, I used adb reverse to tunnel RTSP connection over USB in order to show the stream in Android VLC.

The test is conducted on the outdoor ground with no obstacle.

Result: The video is fairly good at close range. It start to pixelate at 15m and then lose connection at 25m.
Pretty bad result, I guess due to limit of small onboard antennas, AC53 Nano is a smallest-possible USB wifi, anyway.

MuratovAS commented 1 week ago

@MuratovAS Do you have any idea why glitching of input voltage can lead to dc-dc burnout? It is IC design flaw or bad schematics? All three dc-dc in my test dies identically:

I am seeing the power mosfet burn out. IC: tps5430 Possible causes:

Solution:

P.S. I have never used this power supply at a current greater than 2A. The recommended current is 1.5A

svpcom commented 1 week ago

@MuratovAS The main problem is that most of wfb-ng users are hobby users and unable to make custom PCB design themself. Most of ready to buy dc-dc from aliexpress has awful design and overstated parameters. It would be great if someone who specializes in this topic would make such an opensource design, which could be easily repeated by yourself or ordered on pcbway