I'm curious about your input on this issue where I lose FPV signal for a short time after doing quick manoeuvres.

I've been flying FPV with my 210 build happily and without these hickups for at least 15 packs until I decided I'd like to add an OSD (never used one before). I installed the Micro MinimOSD and went flying, but now I can lose my vTX signal for about 1 nerve-racking second if I do a fast manoeuvre like a fast roll. It's not about throttle level. If I ramp up to full throttle on like 1 second and down again as smoothly it's just fine. So I'm thinking it has to do with spikes.

Do you think this a vTX thing or the MinimOSD? I have a 1000uF electrolytic cap on the main power train (LiPo/ESC). vTX is getting power from PDB through a voltage converter (not filtered). MinimOSD is getting power from FC (which has 2200uF electrolytic cap on it). There's a shared ground.

Oh, this just popped into my head: I *did* upgrade to Betaflight 2.9.0. as well and started using superexpo. So in fairness, previously I wasn't rolling as quickly as now. This may be relevant too.

Thanks for your input!

(hopefully somebody smarter than me will chime in too but here's my 0.05 cents)

I was going to suggest a dodgy wire since you've added the OSD, worth checking anyway to make sure you haven't got a loose joint somewhere. Is it typical white lines type noise or is it blacking out completely (a DVR of the flight would be useful too)?

The only other thing that stood out for me was powering the OSD from the FC. I've had issues trying to power the Micro MinimOSD off the FC (LUX) before and haven't bothered since.

Thanks for the half cent Sigloss (good username ) 

About powering the OSD, I should've been clearer. I'm powering the FC through a 2A 5V BEC and I've spliced its 5V out to power the OSD and the FC. So I don't think I need to be too worried about underpowering the OSD, or how would you otherwise suggest I do it? Separate BEC for the OSD?

I don't have a DVR yet so I'll describe. The signal loss I'm talking about it complete static. My FPV goggles briefly flash a 'signal lost' message as I see static, and then it pops back. Beside that I actually do believe that I see more horizontal noise on the FPV signal than before, but that only reinforces my intentions to employ an LC filter for my video signal. I'm inclined to think that these are two separate things though, what do you think?

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Just to add to this: I used Oscar's excellent Micro MinimOSD post as a guideline for my wiring. However, I chose not to connect the vTX GND and the camera GND to the MinimOSD because all my components are already sharing common ground. I only use the VideoIn and VideoOut ports on the left side of the minimOSD. Don't expect this to matter but who knows.

Hmm that sounds ok to me but there are a number of areas that could be causing problems, so it's hard to troubleshoot.

I've also not found a need for LC filters, I run the VTX direct from the PDB and typically power the camera from the VTX or direct from the PDB (depending on input V of camera). I'd also read somewhere about ensuring the ground cable for the VTX and/or camera is as close to the battery ground as possible, i.e. direct to the PDB, which apparently reduces the chance of ground noise. I can't be solid on that last point but it's one of those things I've always done on recent builds and haven't had problems with interference for a while.

In terms of troubleshooting, I'd run a temporary direct video wire from the camera to the VTX (which VTX are you running btw?) and do a test flight. Obviously that would isolate your concerns about Betaflight upgrade and/of course anything else that may have happened during recent changes (and maybe isolate the two problems you suggest).

Yeah you're totally right about isolating the problem by taking the OSD out of the picture (hehe) first. Will report on the findings.

I never ever use the 5 volts from my FC, I always use a stand alone 5 volt 3A bec for the OSD, and never ever had an issue. The FC 5 volts does not always have enough juice for both it and the OSD.

(02-Aug-2016, 10:53 AM)bombarie Wrote: Yeah you're totally right about isolating the problem by taking the OSD out of the picture (hehe) first. Will report on the findings.

I'd suggest leaving the rest of the Micro MinimOSD plugged in (i.e. power, tx/rx, etc), so you're just bypassing the video signal which should isolate if the OSD is dropping the signal before the VTX.

If you have a spare cap (470 should be enough), solder it as close as possible to OSD. I had a lot of problems powering OSD and they came back after I changed ESCs to EMAX lightning_s (from a noisy bad batch so I'm not suprised). After seeing one of the latest Oscar posts about Low ESR caps, I soldered 1000uf one to the power leads on the PDB and the issue went away again. So... low ESR caps are magic

Also I have been seeing users powering micro minimOSD from FC pins mention it can get pretty noisy.

Finally was able to test again. As @Sigloss suggested I wired the video signal directly to vTX while keeping the minimOSD connected to the system as it was before. I experienced no video signal loss now. The faster manouevres (betaflight superexpo) don't seem to be the cause of the dropout. I'm powering the camera directly from PDB which doesn't have noise filtering (just a 7812 voltage regulator), I think I'll add in an LC filter and see what happens.

@Biggles: I'm using a 2A BEC for powering the FC and MinimOSD so shouldn't be a problem.

@Konrad: I already have a 1000uF cap on the main power leads. It's not necessarily a Low ESR cap. How important do you expect that to be? Did you have trouble with a non-low ESR cap before switching to low ESR?

There really can only be two problems then, at least in my mind. Either the MinimOSD has a dodgy video wire or there's a power issue issue on the MinimOSD (also assume the OSD is wrapped and secured, so it's not jumping around or shorting). I personally don't like sharing a BEC between FC and OSD, so would recommend a separate step down for it but again check you're wiring too.

Did you post a pic in the end?

(05-Aug-2016, 02:18 PM)bombarie Wrote: @Konrad: I already have a 1000uF cap on the main power leads. It's not necessarily a Low ESR cap. How important do you expect that to be? Did you have trouble with a non-low ESR cap before switching to low ESR?

Low ESR cap is a lot better than normal one - Oscar posted a video recently of some guy testing different filtering solutions and low ESC 1000uf cap alone was as good as a dedicated LC filter. 

I'm suggesting soldering a smaller cap directly on micro minimOSD 5v line, on pads or pins whatever connection method you are using. If that's a minimosd issue, that should fix it. Those small boards are VERY vulnerable to noise.

I've ordered some low ESR caps, looking forward to testing them! I'll also try adding a small cap to the OSD's Vcc/Gnd pads. Are we talking highfrequency attentuation, say a little ceramic 0.1uf? Or do ceramic caps not offer the same frequency response as an aluminium electrolytic cap?

(08-Aug-2016, 11:06 AM)bombarie Wrote: I've ordered some low ESR caps, looking forward to testing them! I'll also try adding a small cap to the OSD's Vcc/Gnd pads. Are we talking highfrequency attentuation, say a little ceramic 0.1uf? Or do ceramic caps not offer the same frequency response as an aluminium electrolytic cap?

Not sure if so small ceramic cap will be enough to filter the noise enough. Minimosd may reset on a smallest dip in voltage like 0.1V.

If you're into experimenting with smaller size caps, check tantalum capacitors - basically, they are smaller electrolytic type low ESR, most often SMD type, but non-SMD are also available. 470uf 10V SMD one is smaller than 1cm in length and should be enough.

SMD would be perfect between for the VCC and GND pads of the MinimOSD, which I'm not using atm anyway. I'm not amazing at soldering that stuff but as long as it's not the smallest package sizes I should be good. Thanks for the tip, I'll let you know how it went.

(08-Aug-2016, 11:54 AM)bombarie Wrote: SMD would be perfect between for the VCC and GND pads of the MinimOSD, which I'm not using atm anyway. I'm not amazing at soldering that stuff but as long as it's not the smallest package sizes I should be good. Thanks for the tip, I'll let you know how it went.

Not sure if it's that small, maybe also get a 220uf one. But anyway, you can always solder one to a piece of wire
Hope that some of the above helps!