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Loss of video

Joined
Aug 1, 2016
Messages
1,033
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Location
Auburn, WA, USA
Flew my trusty TH today at an abandoned housing development. Nothing but clearings, dirt roads and grass.

Two batteries, no problems. Video was received on the ST16 out to about 1500 feet, then dropped. Still had good visual flight control and video returned on the way back.

Third battery; video dropped out at only a few hundred feet (500-600) out. No trees in the way. No infrastructure to be seen. Even got the loss of WiFi message. Tried rotating, no help. Tried to stop the recording, no effect. Checked receiver antennas; pointed correctly. Gained elevation (~150 ft), got intermittent video signal. Since I had fine visual control, I flew blind for a while hoping that the camera was still recording (it was). When I got very close to the take-off point, video signal came back to the ST16.

What could cause this unusual loss of video signal at such close range? Recordings from microSD card looked great.
 
I'd ask about buried rebar, but you did not mention any drifting or compass errors... :confused:
 
I've been reviewing the telemetry and video files from the camera and controller. I see that the trouble really got worse when I dropped down to about 80 ft above take-off elevation and flew between some trees about 340 feet away. I had excellent VLOS so I thought the video signal should also make it back to me. The video from the controller stopped there and didn't restart until the TH is well back out in the clearing. The telemetry log shows no error message other than occasional compass errors that are unrelated to the video problem.
Are the trees somehow absorbing the WiFi signal? Would a patch antenna help in this situation?
 
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Are the trees somehow absorbing the WiFi signal? Would a patch antenna help in this situation?
Video can drop out for any number of reasons but the main cause is if there is a structure or similar between you and the aircraft...but then you would also probably lose control link too. But structures (and trees) not in the path of the signal can also cause video to drop out because of reflections so, yes, the trees nearby can cause this. And yes, a patch antenna can help.
 
Trees and leaves that typically have a significant water content and are quite good at attenuating radio signals in the high frequencies used.
 
Huh..:(. Thanks, FV and Ron for the feedback. I'll keep that in mind while flying around trees. Unfortunately, we have a LOT of trees here in Western Washington State. I normally fly high over the trees but I've been trying to get closer for dramatic effect in my videos.
This bird has always been pretty sensitive to interference in video transmission; frequent breakups, drop out when rotating camera and glitchy video at the ST16. Maybe that's just normal for the TH system. I'll get a patch antenna and see how that works.
 
I've been reviewing the telemetry and video files from the camera and controller. I see that the trouble really got worse when I dropped down to about 80 ft above take-off elevation and flew between some trees about 340 feet away. I had excellent VLOS so I thought the video signal should also make it back to me. The video from the controller stopped there and didn't restart until the TH is well back out in the clearing. The telemetry log shows no error message other than occasional compass errors that are unrelated to the video problem.
Are the trees somehow absorbing the WiFi signal? Would a patch antenna help in this situation?

This is your initial post
"Flew my trusty TH today at an abandoned housing development. Nothing but clearings, dirt roads and grass.
So there were trees, you didn't mention anything about trees.
 
Rubik, I flew my TH for the entire time I owned it with the Patch antenna... never used the mushroom at all.
 
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This is your initial post
"Flew my trusty TH today at an abandoned housing development. Nothing but clearings, dirt roads and grass.
So there were trees, you didn't mention anything about trees.
OK, you got me there :oops:. The trees were surrounding the clearings, dirt roads and grass. It's when I ventured into the trees that the video transmission problem became critical. Even before that, the video transmission was breaking up occasionally at 1000-1500 feet in the clearings. The TH was in clear VLOS at all times, nothing directly between me and the bird.
 
OK, you got me there :oops:. The trees were surrounding the clearings, dirt roads and grass. It's when I ventured into the trees that the video transmission problem became critical. Even before that, the video transmission was breaking up occasionally at 1000-1500 feet in the clearings. The TH was in clear VLOS at all times, nothing directly between me and the bird.
I often fly in areas that have loads of trees but I seldom get video issues caused by them. I tend not to fly out very far, though, if there are lots of trees around...reserving my longer distance flights to areas with less, or no, trees.

The furthest I've ever flown my H was 500m (the legal maximum allowed in the U.K.) and that was just the one time. But that was an area that had few if any trees and I was standing on high ground. Video was steady with no signs of cracking up at any point. Video of that flight below (please forgive the blow out whites).
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Edit. After viewing the above video again I decided to do a re-edit taking more care of colour grading. You can see it here if interested. A Re-Worked Video Edit
 
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I hate to admit it now, but shortly after I got the TH back in 2016, and after I had determined that it was reliable, I tested the published range specs. The TH flew out over 1 mile at just under 400 ft elevation over level, uninhabited ground before loosing video. I was pleased to see how well RTH worked. I'm not sure what has changed since then (other than firmware updates?). I have no desire to fly that far away, now that I understand the regulations better. But my video range is now less than my VLOS range.
 
Update: I flew this morning with the same camera setup as before but at my favorite local site where I have unobstructed LOS over uninhabited ground for much farther than I am willing to fly. The range at which the video started breaking up was much farther than I reported above. Also, my elevation for this test was just under 400 ft. This means that the short video range I experienced previously was solely due to the proximity of trees near the drone and low elevation. Lesson learned.
 
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Maybe check the st16's antenna.
Since it worked well, then started getting bad, you could have a bad antenna.
If so, the ST16's 5.8gHz Tx could be hurt next.
 
Thanks for all the suggestions. I think we can put this one to bed. Stay out of the trees!
BTW, I have a patch antenna on order.
 
Thanks for all the suggestions. I think we can put this one to bed. Stay out of the trees!
BTW, I have a patch antenna on order.
Don't forget that the patch antenna is highly directional so you need to keep it pointed at the aircraft (it's what helps it give better range and cut through interference), but I'm sure you know that.
 
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Update #2: I went back to the location where I lost video prematurely. This time, with 2 improvements to the TH: a patch antenna on the ST16 and a modification to the camera antenna. The modification consisted of pulling the camera butterfly antenna out of the housing and fixing it to the bottom of the housing pointing straight down when the camera is horizontal. This should improve the distribution of the video signal from that antenna, no matter the horizontal orientation of the camera.
Well, the same problem occurred :(. Any time I flew toward the treed ravine and meadow just beyond the south end of the cleared area, the video at the ST16 would drop out and take a long time to reestablish. The problem persisted even well above the trees. Looking at the GPS data in the log, I see that there was also a lot of unexplained deviations in that as well. I never lost control (that I could tell) and landed safely. The only conclusion that I can think of is that there is something in the ravine south of the cleared area that interferes with WiFi and, possibly, GPS. There is a small ranch in the meadow there. Hmmm....
 

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