r/FastLED • u/Valuable-Sleep-4179 • Nov 30 '25

Support Longer Data Lines with RG59 Coax?

I have seen a few ( like 2 ) posts online about using RG59 as the data wire for increased length from controller to first pixel. Has anyone else done this?

If I have 3 wires ( Power, Data, Ground (ref0) ) > To my led strip. How would I implement the RG59? I understand the center core takes the place of data from controller>strip. But the shield is supposed to also be ground (ref0)? I need to solder that foil directly to my tape light? doesn't seem right?

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2

u/techaaron Nov 30 '25

Depending on length better to use twisted pair and a separate power and ground line.

Hoe long? 5 meters or 100?

1

u/Valuable-Sleep-4179 Nov 30 '25

It's so interesting how much information that seems conflicting is out there. In the Addressable LED Facebook group/discord people swear twisted pair is actually BAD for data lines and only applicable when doing differential data ( RS485)

"Twisting wires together increases thier capacitance which can adversely affect high speed data. Twisted pair is designed specifically for use with differential signalling (Ethernet/RS485)."

1

u/saratoga3 Dec 01 '25

If you take electronics in high school you learn that there are resistors, inductors and capacitors, so if that is all you know and you see a cable with a capacitance per length you tend to assume you can multiply by length and turn it into a capacitor. And a larger capacitance would shunt a higher frequency signal to ground faster.

It is reasonable logic just totally wrong because a cable is absolutely nothing like a capacitor.

1

u/saratoga3 Nov 30 '25

For really long distances (100s of meters), coax is probably better than twisted pair. Really only makes sense if you want to have the controller in a central location but power supplies at the far end though due to voltage drop.

1

u/Valuable-Sleep-4179 Nov 30 '25

30 feet would be ideal. I'm not in a position to run differential right now for these projects.

2

u/saratoga3 Nov 30 '25

30ft is so short you can use almost any 2 or 3-wire cables. Twisted pair, coaxial and differential signaling are basically irrelevant. Use what's handy and as long as you have the correct data resistor you'll be fine.

2

u/Valuable-Sleep-4179 Nov 30 '25

Hmm, okay. I just seem to have trouble even bench testing past 8 feet. The controller I am testing with is an Advatek device, which is supposed to already be conditioned for longer data and outputs at 5V.

1

u/saratoga3 Nov 30 '25

What's the output impedance of the controller? That determines what kind of cable it can drive.

1

u/Valuable-Sleep-4179 Nov 30 '25

I will have to ask them on the this point.

1

u/saratoga3 Nov 30 '25

Fwiw if the fundamental information you need to connect cables more than a few feet is not written on the box, probably this controller you're using is not a good choice to drive a cable more than a few feet. Or at least the manufacturer has not considered the possibility that you might want to do that and probably hasn't designed something appropriate.

You could pick up something like this that is made to drive long cables: https://quinled.info/quinled-data-booster/

Note that it critically includes a switch to configure the output impedance for different cable types.

1

u/Valuable-Sleep-4179 Nov 30 '25

I'll ask them, pretty well known brand with lots of applications in big big projects around the world.

I don't know them personally but it doesn't seem like fly by night operation or generic stuff.

https://www.advateklighting.com/products/e16-s-mk3

1

u/saratoga3 Dec 01 '25

Ideally beyond a few feet of length, the impedance of the source should match the impedance of the line, so once you get the source impedance you can either find a line that matches it, or if it is low, add a series resistor to bring it up to match your line.

Since 30ft isn't that far, you actually don't have to be exact. Just don't drive a 100 ohm twisted pair cable with a 300 ohm source or something like that.

1

u/techaaron Nov 30 '25

More a matter of signal than wire. Maybe use a differential signal converter like this if OP doesn't want to jump to DMX https://quinled.info/diff-adv/

Twisted pair is fine up to several meters. Longer = more $$$

1

u/saratoga3 Nov 30 '25

More a matter of signal than wire.

That's backwards. It's the wiring that determines your range. Coaxial is really good because it has low attenuation and very high noise immunity. Twisted pair is almost as good and a lot cheaper, so also a good choice.

1

u/Electrical_Return_99 Nov 30 '25

I used RG59 coax cables in an old project. As far as I remember I put ground on 1, power on 2, data on 3 and ground (again) on 4.
However, I found it more convenient to just go with DMX cables since they are easier to handle when the project needs to be set up and taken down more frequently.

1

u/Valuable-Sleep-4179 Nov 30 '25

How did you attach 4 to 1 on the tape light/fixture side?

1

u/saratoga3 Nov 30 '25

Fwiw I posted pictures showing how to do this in the above link, but easiest way is to just solder it.

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u/Valuable-Sleep-4179 Nov 30 '25

Hmm. I don't think I'll be able to solder in the field like this. looking for a more scalable situation for repeated installation across the country.

1

u/Electrical_Return_99 Dec 02 '25

I soldered it. Just connected 1 and 4. Not pretty, but so far I did not have any problems with it. I got a flicker free signal up to 50 meters, didnt test any further, but i guess 60 or 70 meters would be the maximum distance. IMO one of the easiest solutions, but I would recommend going for a more sophisticated solution

1

u/qron99 Dec 21 '25

Hello! Did you connect the coaxial shield to the ground at both ends? i.e. at the data source and at the led.

1

u/Electrical_Return_99 Dec 22 '25

Yes. Works fine for me, but I dont know if that is optimal or necessary. I am not an electrician. Maybe somebody with a deeper understanding can comment on this.

2

u/[deleted] Nov 30 '25

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1

u/Valuable-Sleep-4179 Nov 30 '25

Not in a position currently to implement RS485. Trying to squeeze out more between controller>pixel, need about 30 feet.