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VTX Switching Channels Mid Flight
#1
When I take off with a fully charged battery my quad flies for 10 seconds and then the vtx/goggles (not sure) switches 2 channels. Regardless of distance/speed. After I crash the video comes back. 
I know it is switching channels because if I have someone else look through goggles as I fly line of sight they are able to switch down/up 2 channels and have the video work.

When I take off with my battery at 14~15v it flies fine, and the video looks great.

I have replaced, VTX, Camera, osd, wires, tx antenna
Camera running on 5v, osd on 5v and vtx on 12v
I am suspecting the 12v regulator on the pdb. People in the reviews of the pdb say it is bad but I don’t know if that is causing the vtx to switch channels.

Setup:
Ts5823
Matek PDB: http://www.banggood.com/Matek-Systems-PD...mds=search
Cloverleaf antenna
Teleporter V4
HS1177
MinimOsd

UPDATED INFORMATION:
Takes exactly 20 seconds for video to go out at 16.4v
As soon as battery hits 15.5v there are no dropouts.

Datasheet for 12v regulator:
http://www.st.com/content/ccc/resource/t...000447.pdf
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#2
I've never heard of this before, but I highly doubt it has anything to do with the PDB. If you've replaced everything and it's the same, it must be in your setup. If it does it with both VTXs, I'd rule that out and concentrate on the goggles. Possible a faulty channel search button? The only other thing that comes to mind is how you have your VTX fastened. If it's with a ziptie and it's across the channel switching button, maybe the movement of the quad is causing the ziptie to compress the button?
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#3
(25-Nov-2016, 05:30 AM)RENOV8R Wrote: I've never heard of this before, but I highly doubt it has anything to do with the PDB. If you've replaced everything and it's the same, it must be in your setup.  If it does it with both VTXs, I'd rule that out and concentrate on the goggles. Possible a faulty channel search button?  The only other thing that comes to mind is how you have your VTX fastened.  If it's with a ziptie and it's across the channel switching button, maybe the movement of the quad is causing the ziptie to compress the button?

There is nothing hitting the dip switches, however I don't remember if this happened with my old vtx, I don't think so. But the one I have on it now was brand new.
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#4
Simple ruleout, do you jave acces to other gogles especialy other vrx? This way we can narrow it down to quad
All the best
Grzesiek (Grisha/ Greg)

Curently flyable: Nox 5, Minimalist 112
Bench / in progres: fixing Nox 3,  Scrap
thinking about building: 450


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#5
Does it also happen in a gentle hover? I.e. when it doesn't draw a lot of battery power.
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#6
(25-Nov-2016, 10:14 AM)fftunes Wrote: Does it also happen in a gentle hover? I.e. when it doesn't draw a lot of battery power.

Yes it happens regardless if I am in a gentle hover or an all out burnout
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#7
UPDATED INFORMATION:
Takes exactly 20 seconds for video to go out at 16.4v
As soon as battery hits 15.5v there are no dropouts.

Datasheet for 12v regulator:
http://www.st.com/content/ccc/resource/t...000447.pdf
Reply
#8
No clue about that PDB, but on my quads i feed my vtx directly from battery balancer plug (just using 3 cells of the 4s packs).
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#9
(25-Nov-2016, 06:07 PM)fftunes Wrote: No clue about that PDB, but on my quads i feed my vtx directly from battery balancer plug (just using 3 cells of the 4s packs).

How did u make that?
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#10
(25-Nov-2016, 06:14 PM)tdogb Wrote: How did u make that?

A balancer extension cable soldered to vtx, but cut off 2nd, 3rd and 5th wire, so there's only ground wire and the one coming from 3rd cell.
[-] The following 1 user Likes fftunes's post:
  • sloscotty
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#11
(25-Nov-2016, 06:36 PM)fftunes Wrote: A balancer extension cable soldered to vtx, but cut off 2nd, 3rd and 5th wire, so there's only ground wire and the one coming from 3rd cell.

What a great tip fftunes!
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#12
(25-Nov-2016, 06:50 PM)sloscotty Wrote: What a great tip fftunes!

Thx Smile i also find it convenient to not have to power it all simultaneously - i can check video before powering motors or fly LOS without video.
Just make sure your vtx is protected from voltage spikes.
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#13
I actually have a feeling it is a temperature issue with the voltage reg. A higher difference in voltage e.g. 16.4v and the 12v output means the chip will get hotter.
However it started acting weird again when it was really hot outside, but when I came inside and let it cool off it worked fine again.
I could try puting on a heatsink, but do u guys have any other ideas?
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