Thread: Shielded video cable?

Remove your tin foil hat and use it to wrap the cable.

I am not a pro.


Does that occur if you temp mount the camera elsewhere on the bike?

I haven't followed your solution build but if you have sensors and other things feeding that, have you tried relocating them or unplugging selectively?

That seems like something in the ignition is actually spiking a component with some interference and the cable is just a victim, OR something sn't grounded or fully isolated.

Shielded cable is good for rejecting noise but it's also good for carrying it back to the source, and if the source doesen't have a drain integrated for the shield really weird things can occur. Typically this isn't as evident in video as it is in data which is why I am still thinking an ignition device is on plane with the cam or something and basically injecting it with signal.


p.p.s. I am not a professional as stated above.

Originally I had a cam on the front with the cable running to the truck to be recorded. When I got the new recorder that was still the case. I got noise but it was the cam going out and not bad. When I got my switch in I ran the front cam to the switch and the back from there to the front and into the switch with a RCA cable I had laying around going from the switch to the recorder.

If you notice the interference starts in the first video when the bike starts with RPM affecting the level of noise. So I am thinking the cable running from the switch back needs to be shielded. I also plan on seeing if the cable coming in is going by the ECU in a strange way (the previous system came by on the opposite side)

Originally Posted by SheepOfBlue

Originally I had a cam on the front with the cable running to the truck to be recorded.

Sorry but I keep getting stuck here, I can't even find a word to stick in there that makes sense.

...also, if the rca cable you used is one you had laying around and isn't one that is actually a video cable, it might have something to do with things as I thought the cables were a slightly different impedance than audio signals.

Er... I know this sounds silly, but have you considered vibration? Them big V twins are pretty vibey....

Originally Posted by NinerPilot

I think he meant trunk instead of truck... At least that makes sense.
Chris

Yes...you sir win the price. I kept thinking cable track or something...ok strike my comment.

Im guessing bad cable routing

Where do you get you power from? If you're getting it directly form the bike battery you probably need one of these. MobileVideo4Less.com: Basic Power Line Noise Filter

Originally Posted by SomeStrangeGuy

I am not a pro.

That should be your signature

Originally Posted by SomeStrangeGuy

Sorry but I keep getting stuck here, I can't even find a word to stick in there that makes sense.

trunk sheepism

Another thought that occurred while talking to a coworker. The previous cable routing (cam direct to recorder) was taped to the frame and the current one I tucked it under the tank so the frame is no longer between it (I did it for appearance and figuring nothing would get caught on it)

I think I am going by Radio Shack on the way home to get a cable that is shielded and might more the routing....

If it's tucked under the tank you might be picking up some noise from the coil packs.

Originally Posted by ND4SPD

If it's tucked under the tank you might be picking up some noise from the coil packs.

That is what I figure. The main question is shielded cable or move it outside the rail.... or both. I like underneath as it is very clean looking.

Originally Posted by SheepOfBlue

That is what I figure. The main question is shielded cable or move it outside the rail.... or both. I like underneath as it is very clean looking.

Old RCA cables are already shielded . . . They just aren't the correct capacitance and length/impedance coupled. Try using a proper 75 ohm video cable.

Originally Posted by abtech

Old RCA cables are already shielded . . . They just aren't the correct capacitance and length/impedance coupled. Try using a proper 75 ohm video cable.

I assume you are meaning coax? The connectors on both ends are RCA....

Originally Posted by SheepOfBlue

I assume you are meaning coax? The connectors on both ends are RCA....

RCA jack terminated cables are used for several applications as they carry the effective shield all the way through the connection by design. The differences all have to do with the cable used.

Any single insulated conductor cable covered with insulation and then a shield is coaxial cable, but the series and parallel capacitance of the cable and it's expected length/termination impedance will vary widely based on the cable construction and materials. I would check the manufacturer's recommendations and follow their guidelines. I would also consider using Canare or Mogami cable as these offer higher than standard velocity factors, better and more complete shielding as well as higher flexibility than conventional coaxial cables.

Thanks for the feedback. I thought on your comments and figured it wasn't cable maybe but the powerline picking it up. So I did two short runs. The first was with the cam plugged in, the second running off a battery pack. There is little to no noise in the battery pack version (this is similar to something I saw on the Chasecam support area) I do get a bit of frame drop but I think that may be the cam. I could also add a filter on that maybe....

So I am headed out to get a filter like JetBDude posted to put in the line

Hopefully not a water filter?

Filters seem to not exist much anymore. Ideally I build a 8-15.5v to 12v converter that gets rid of ripple but there is no time. I installed a ferrite bead and that helped but tonight I add a wrap and some tin foil on the other end

So here is with a ferrite bead on the recorder power line (no loop as I did not have space) and about 80% of the length wrapped in tin foil. The rear cam runs from the unit but the front runs off the headlight harness. It is wrapped in tinfoil and has a ferrite bead with one wrap. I think it is good enough

Originally Posted by SheepOfBlue

So here is with a ferrite bead on the recorder power line (no loop as I did not have space) and about 80% of the length wrapped in tin foil. The rear cam runs from the unit but the front runs off the headlight harness. It is wrapped in tinfoil and has a ferrite bead with one wrap. I think it is good enough

What will you use for a hat now?

They still sell tin foil down there? We only get aluminum foil up here these days.

How does a non-ferrous paper-thin material provide any shielding?

Originally Posted by abtech

They still sell tin foil down there? We only get aluminum foil up here these days.

How does a non-ferrous paper-thin material provide any shielding?

Interesting points but the result is the result Aluminum does conduct and all I am trying to do is block RF (though you are correct it should not have any effect on the emag portion) The real solution is to make a DC/DC converter that filter ripple and is current limited for safety with the nice cam compatible plugs but time is....

Originally Posted by SheepOfBlue

Interesting points but the result is the result Aluminum does conduct and all I am trying to do is block RF (though you are correct it should not have any effect on the emag portion) The real solution is to make a DC/DC converter that filter ripple and is current limited for safety with the nice cam compatible plugs but time is....

I seriously doubt that the aluminum foil has any effect at radio frequencies. The foil used in shielded cable is a ferrous alloy specifically targeted to work above 200 KHz. You really would have better results using Mogami foil+braid 75 ohm coax. Your ferrite beads could then be used for a necklace . . .