Diagonal lines in the video - RC Groups
Thread Tools
Sep 08, 2011, 08:41 PM
Registered User

Diagonal lines in the video

I'm getting diagonal lines in the video, even with the RX/Motor not connected.

The video system is powered by a separate 3S battery pack with a LC filter. The setup is

Battery -> Fy-AP117 OSD -> BevRC WDR700 camera -> Fy-Ap117 OSD -> Immersion RC 5.8 TX

All wires are twisted except the wires from the camera to the OSD but that was the same with the old camera

This didn't happen with the DX201 camera, is there a way of getting rid of the noise without replacing the camera?

Sign up now
to remove ads between posts
Sep 08, 2011, 09:32 PM
Registered User
Toysrme's Avatar
ground loop?
Sep 08, 2011, 10:54 PM
Registered User
Hugeone's Avatar
Counting the lines and multiply by 15750, you'll have the beat freq. of the interfering noise.
Look like it's the 400-500khz range. Might be a defective on board step-down of the camera.

Sep 09, 2011, 01:55 AM
Registered User
Toysrme's Avatar
huge is a beast
Sep 09, 2011, 06:17 PM
Registered User
I'm going to suggest you power the VTx at 2S (tap the balance lead for 7.4v).

Any improvement?

Sep 09, 2011, 10:10 PM
Outta Sight
I think Devon is right.
I have seen this coming from the IRC Vtx.
To experiment, try powering the VTx with a separate 2S LiPo, it should clear up.
If the Vtx is connected to the camera with the same power supply this will happen every time.
Goodluck. Let us know how you go.
Sep 09, 2011, 10:29 PM
Registered User
Hugeone's Avatar
I saw it on the foxtech 5.8 Vtx, the onboard 3.3V step-down produced similar lines. Bad filtering design or something, I have two and both does this.

However, the IRC designer brag a lot about his attention to details so I doubt it could be the Vtx. Anyway, those lines are from switching power supply somewhere in your setup.
There's one in your camera and one in the Vtx.

Tip: Touch and hold the Vtx, look for change in the lines, do the same with other thing you may suspect.

Sep 10, 2011, 04:19 AM
Registered User
I have this same 'herringbone lines' issue with onboard switching regs on another Immersion VTx and another well known VTx (not a Chinese product and the supplier is also well respected).

I made a test powering from a variable voltage linear power supply and you can see the differences here (click through to watch it directly on Vimeo in a larger screen)...

5.8GHz VTx problem (0 min 59 sec)

My gut feel is still with filtering as I had a similar problem on a homebrewed 5.8GHz setup...

Homebrewed 5.8GHz FPV rig - First light. (2 min 23 sec)

Improved filtering resolved it...

5.8GHz with improved video (1 min 2 sec)

Last edited by Devonboy; Sep 10, 2011 at 08:02 AM.
Dec 13, 2013, 12:46 PM
Registered User
I know I'm digging this up, but I have the same exact problem with my ImmersionRC 600mW 5.8 GHz Tx. Thanks for posting the video with the varying DC PSU, Nigel. I'll try powering my VTX off 2S. Would there be any issues in throwing my lipos off balance if I tap 7.4V off the balance lead of my 3S packs? I'd prefer to not add the weight of a second battery.
Dec 13, 2013, 02:22 PM
Registered User
I haven't had any issues with tapping the main LiPo pack for lower voltages and low power consumption devices.

Feb 17, 2014, 12:46 AM
Registered User
It is inconvenient to need to tap off the lipo balance lead. Has anyone tried adding more filtration to the TX PCB after the switching regulator (such as a larger inductor)?
Sep 18, 2017, 08:15 AM
Registered User
dogshome's Avatar

Switching beat frequency and video lattice

Guys I finally found this very useful thread after much searching, modifications and poor video. I searched "Video interference", "Bit Crawl", "Composite video noise", "FPV poor video", "FPV video lattice" etc etc and found NOTHING for weeks. Finally spotted this semi-randomly! So definitely worth resurrecting this thread IMHO

The key to my issue is the vtx and camera switching regulators interfering (by being on the same common supply) and solving that by introducing inductance between them.

This is my transmitted video now in the small frame vs before filter in the background. The raw HD on my 1080 laptop shows it better than on Youtube conversion, but you'll get the idea:

VTX to camera filter (1 min 18 sec)

Some technical backup here:


100uH and 1uF ceramic cap LC filter made by carving up and removing the other components from a 1.67 9V switch regulator PCB. With some heatshrink over it, it's still tiny and looks like it wasn't carved up with a Stanley knife, 60W mansized iron and snapped in half over the corner of the bench
Last edited by dogshome; Sep 18, 2017 at 08:30 AM.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Getting horizontal lines in video with a separate battery OrlandoP FPV Talk 7 Aug 14, 2011 10:15 PM
Discussion Lines in video yellowcolorado FPV Talk 20 Dec 31, 2009 03:39 AM
Help! Lines in video when motor running...help please. cadders FPV Talk 17 Dec 14, 2009 10:08 PM
Discussion How to get rid of lines in video EyeFlyPlanes FPV Talk 10 Jul 02, 2009 04:34 AM
Discussion Image problem - diagonal lines DerKorb FPV Talk 6 May 01, 2008 04:41 PM