So I recently finished building a 3" Micro Reverb (they aren't kidding when they say its tight...). I ended up having to reconsider the components of the build as the connectors/components on the Caddx Baby Turtle's board and the 20x20 VTx made it impossible to fit in the 20mm available stack height, even with the HGLRC Zeus35 FC/ESC AIO board.

So while waiting for new parts to arrive I put in a Foxeer Toothless micro with the Holybro Atlatl micro HV. No HD footage but at least it will fly! Everything worked as expected all the way up to the max output power of 800mW. Crystal clear, crisp video link. I had the VTx running on vBat and the cam on the 5V rail with both on the same ground pad, 35V 220uF cap on 3S/4S LiPo in.

Once my TBS Unify Pro32 Nano arrived I swapped out the Atlatl VTx and replaced the Foxeer with the Baby Turltle. I also replaced the fullsize TBS Triumph MMCX with a u.FL to SMA pigtail and a Lumenier Micro AXII on a TPU mount. The video noise (white lines) is so bad I can barely fly it.

The noise only shows up when armed and motors spinning. The part I don't get is the issue is only present when then Unify's output power is at 400mW or Max. At 25mW/100mW everything looks fine... So just to be clear, these are the changes to the setup that have introduced this problem:

• Atlatl VTx board was replaced by the Caddx Baby Turtle's board, mounted above the FC.
  
• Unify Nano is mounted on top of the Turle board with double sided foam tape. The u.FL connector is facing down, away from the top plate and can't come into contact with any carbon or the board below.
  
• The cam is now running off vBat as the VTx can only take up to 13V and I'll be running 4S, so 5V for that. Both are still grounded on the same pad.
  
• Different antenna assembly.
  
• The only way I could fit the antenna pigtail was by running it between the two LiPo leads. Not ideal I know but I don't believe this is the root cause.
  

Here's a small gallery of the current layout.


So far I've tried, without success:

• Running the cam off the filtered VTx passthrough, so 5V.
  
• Reoriented, changed placement of the VTx on top of camera board.
  
• Applied heat-shrink the the part of the SMA mount that is close to the carbon fibre. Also put silicone glue on the surrounding recess in the frame to help isolate, just in case. 
  
• Made sure there were no components coming into contact with each other or the frame that shouldn't be.
  

Really not sure what to look at now. It seems odd that 400mW+ is a problem especially now that the end of the VTx antenna is much further out. The Atlatl had the antenna head wedged between the rear standoffs and ran perfectly at 800mW...

Full parts list:

• ImpulseRC Micro Reverb 3"
  
• HGLRC Zeus35 F4 FC & BLHeli_S 4in1 35A ESC
  
• Apex Racing 1303.6-5000KV running 3S & 4S
  
• TBS Unify Pro32 Nano v1.1 VTx
  
• TBS u.FL to SMA pigtail with Lumenier Micro AXII
  
• TBS Crossfire Nano Receiver
  

Thanks in advance, it's pretty much always you guys who save me when I'm standing around scratching my head like this!

Hey, I am not sure that it would help, but check your crossfire antenna. Hold the antenna with hands, if it is possible and ccheck if the lines dissapear. I've had some lines, and they are gone when I've changed my receiver antenna..I don't know if it is the real problem, but I have tried a lots of things..and only this helped

(02-Nov-2020, 11:09 PM)ethr Wrote: Hey, I am not sure that it would help, but check your crossfire antenna. Hold the antenna with hands, if it is possible and ccheck if the lines dissapear. I've had some lines, and they are gone when I've changed my receiver antenna..I don't know if it is the real problem, but I have tried a lots of things..and only this helped

Thanks for the suggestion! I actually also have this issue since the beginning, only way to correct it is, as you said, holding the antenna tips in my hand or turn off telemetry on the XF receiver.

That interference is annoying but bearable. The noise I'm getting now is way more intrusive and obstructive. I can only barely make out the image when it starts getting real bad whereas the crossfire telemetry issue is very consistent.

This looks very similar to an issue I had a while back where my SMA was touching the frame but I can't figure out what's causing it!

I had to run my unify pro32 nano off a bec powered by vbat set for 9v to clear up the noise on it. It wasn’t as bad as yours was. I used the matek 5-9v bec. It’s pretty small.

(05-Nov-2020, 12:54 AM)Rick h Wrote: I had to run my unify pro32 nano off a bec powered by vbat set for 9v to clear up the noise on it. It wasn’t as bad as yours was. I used the matek 5-9v bec. It’s pretty small.

Thanks for the advice, I'll try this next.

(05-Nov-2020, 12:54 AM)Rick h Wrote: I had to run my unify pro32 nano off a bec powered by vbat set for 9v to clear up the noise on it. It wasn’t as bad as yours was. I used the matek 5-9v bec. It’s pretty small.

So I essentially rebuilt the whole thing:

- switched to a 470uF at the XT30
- added a Matek BEC drawing from a VBat on the FC and set to 9V
- BEC feeds the Unify and the Unify's filtered passthrough goes to the Caddx Baby Turtle
- before, the VTx was heatshrinked and on top of the camera board with foam tape. Now it's installed using the 20x20 board provided with the Unify, under the camera board (above the AIO FC/ESC)
- video signal wires much much shorter than before and routed away from the stack
- camera harness routed over the top of the camera board
- changed to a shorter, more flexible antenna pigtail and resoldered the lipo leads to route them away from the antenna

All this made literally no difference... 100mW life's good. 400mW+ all hell breaks loose.

This video at 20:00 minutes I’m shows a good method for cleaning up video noise that may be beneficial.