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Old May 26, 2015, 12:41 PM
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RunCam HD camera has internal copper paint shield. Which does not protect from UHF noise completely, as I measured, UHF noise still gets a lot outside of the case. That it is why I had to make aluminum foil outside of the case also, which helped a lot with it.

I removed my external aluminum shield and opened RunCam HD.
I measured with ohm meter and found that the internal copper paint shield is grounded to the same ground if USB cable is connected.

Could that cause that internal copper paint shield could work as UHF antenna and could cause that the noise gets to the other electronics (like E-OSD) via ground?

Would not be better if internal copper paint shield would work more like farraday cage, not grounded with no ground connected?

Quote:
Originally Posted by changosurf View Post
always use ferrite chokes on all of your long wire runs.
keep EVERYTHING away from the UHF RX, all electronics: UBEC's, flight controller, FPV transmitter, HD camera, OSD, everything!!!

If you're going to run something like a RunCam/Mobius/GoPro, keep it as far away from the RX as possible. Shield them with lots of copper or aluminum tape.

Make sure there are NO ground loops in your setup, through your FC, OSD, UBEC, whatever... You ideally need a 'star' ground configuration that ties back to your battery's negative terminal.

Consider using shielded cable such as CAT-6 network cable for all of your wiring runs. Ground the shield only at one end, the end closest to the battery. Twist all of your wiring into twisted pairs.

Check your existing wiring harness and make sure that you don't have any runs whose length(s) are even multiples of the 433 wavelength. If so, try to eliminate the length resonance, add a choke, twist the cables, or all of the above. Get rid of any wires/connections that you don't need.

What video frequency are you using? Make sure your FPV transmitter & the channel you're using isn't putting out noise on the UHF band.

Get a better set of antennas.
Check the power output from your TX.
Get an RX unit that has the on-board filter.

go read this entire thread:
http://fpvlab.com/forums/showthread....433mHz-Control
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Old May 26, 2015, 04:30 PM
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Interesting UHF noise measurement of standalone RunCam HD with and without USB cable

Some interesting UHF noise measurement of standalone RunCam HD camera.

I created new aluminum foil shield for RunCam HD again and switched it on. USB cable is not connected. No UHF noise was measured. Nice.
Name: new shielded cased RunCam HD USB cable disconnected.jpg
Views: 12
Size: 155.7 KB
Description: Standalone switched on RunCam HD with added aluminum foil shield UHF noise measurement. No UHF noise measured.

Then I connected USB cable to RunCam HD which is switched on, USB cable is not further connected to anything. Just only to RunCam HD. Now there is UHF noise around RunCam HD.
Name: new shielded cased RunCam HD USB cable connected noise.jpg
Views: 13
Size: 157.4 KB
Description: Standalone switched on RunCam HD with added aluminum foil shield with connected USB cable which is not connected to anything UHF noise measurement. No UHF noise goes outside with help of USB cable.

Any tip how to eliminate noise in this case?
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Last edited by pavn; May 26, 2015 at 04:57 PM.
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Old May 27, 2015, 12:28 AM
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Hi pavn,
just dropped by to say you are a great help in solving my own range problems with UHF.
Keep up the good work documenting all of this

Try shielding USB cable with the foil and measure again.
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Old May 27, 2015, 04:00 AM
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Tuned RunCam HD with USB cable farther

Thanks. It takes a lot of effort and pain to tune it. It probably could be pain to post so frequently to this thread, but I never seen OpenLRS tuned setup step by step tutorial. Only general advices. But it looks like it is more complex. I always had problems with OpenLRS control. First I tried to use Open LRS was with my MaxiSwift flying wing and HobbyKing Orange Open LRS 100mW JR transmitter and receiver. Exchanged antennas. But it was not enough. Luckily I used APM 2.5 autopilot, the way that it always helped me to more or less not crash with it at all. But the range was not good and stability also was not good. I tried also separated electronics as much as possible. It was better, but it was not safe still, I am sure. Using many hop channels did not solve it. Now I try to fly without autopilot (with custom built Blunt Nose Versa flying wing) and that it is why Open LRS control needs to be more robust. It takes a lot of pain. Since I crashed because of loose of control, not far away - just around 1.3 Km max distance two times. Last time this weekend it was just 750 meters. In that case I though that I have tuned setup, it was not tuned enough. Aluminum foil shielded RunCam HD produced no noise. But if USB cable was connected, it created substantial UHF noise on other components - on shielded E-OSD, and Mini step down 5V power supply component. I did not know it, did not measure it that way and it caused loose of control not far away 750 meters in about 200 meters height, also with some little more UHF noise in environment probably from power lines or something. But it looks that it is progressing right way. And I am starting to get very interesting results. Especially considering that I am testing on lowest possible Open LRS transmitter power setting - 0 value. I now can get on this setting to the end of the garden and I am still in control, leaving transmitter at home and with many trees in the garden both with PZ0420M connected as camera or RunCam HD now. RunCam HD now does not cut my remote control link if it is connected.

Yesterday I tried to solve the issue that if USB cable was connected to aluminum foil shielded RunCam HD, it simply produced UHF noise again, although aluminum foil shielded RunCam HD alone without cable connected produced zero UHF noise.

I tried to tape part of metal part of the 10 pin mini USB connector the way that if USB cable is connected to the aluminum foil shielded RunCam HD, that it does not connect USB ground to the aluminum shield. And looks like it helped a little further again.

The UHF noise measured is lower than when USB ground was in connection with aluminum foil on RunCam HD.

Ground tests today proved the better UHF noise results with RunCam HD. I was able to walk to the end of the garden with aluminum foil shielded RunCam HD with USB video cable connected. It simply did not cut my remote control link now.
I tried to position RunCam HD and not shielded Mini step down 5V power supply as near as possible to DTF UHF mini long range receiver and antenna. And it simply did not cut me. It was hard to get the effect to cut remote control that way now.

I did further tests. I left airplane at home, video and everything connected. And walked outside to the garden with RC transmitter and Fatshark video glasses with connected Boscam 2.4 GHz receiver. I was at the end of the garden and my video was weak and unstable, I saw still something if I tried to position CP antenna some way. The way I could read RSSI value and measure and compare RSSI when PZ0420M camera was connected with RunCam HD camera connected. When RunCam HD was connected I was getting around 2.4V at home near the airplane. Outside, at the end of the garden I was getting around 1.35V at max. But the airplane was still in control with RunCam HD, RunCam HD did not cut me this time as was tested in previous test. With PZ0420M camera it was around 2.53V RSSI at home near plane and 1.86V outside at the end of the garden. It looks like that still PZ0420M is more safe to fly especially for longer range and more safe flights. But good progress is that RunCam HD does not cut me this time, although UHF noise produced when it is connected makes RSSI value lower, but it is still in control. Considering 100mW transmitter on lowest possible power - 0 value in settings, one building and many trees on way and at the end of garden still in control with both camera combinations. I am looking forward for some flight test.

If I will be able to tune stable OpenLRS long range remote control, I will hopefully try to create some step by step how to tune OpenLRS for stable and long range tutorial as help for other users and help for open source community. I will try to post it here also with some crash experiences with not tuned setups.
https://www.youtube.com/pavel4n

Previous aluminum foil shielded E-OSD UHF noise generated when RunCam HD was connected via USB cable. See attached image.

Current aluminum foil shielded E-OSD UHF noise generated when RunCam HD is connected via USB cable. See attached image.

Quote:
Originally Posted by Phoboss View Post
Hi pavn,
just dropped by to say you are a great help in solving my own range problems with UHF.
Keep up the good work documenting all of this

Try shielding USB cable with the foil and measure again.
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Last edited by pavn; May 27, 2015 at 04:17 AM.
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Old May 27, 2015, 08:04 AM
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spectrum analyzers are cool!!
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Old May 31, 2015, 01:33 PM
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Can someone please help me, i cant compile anything in Arduino anymore it just compiles endlessly and is like stuck at 25%.
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