Author Topic: Want 300 feet runs from your controller? Use Coax  (Read 2714 times)

Offline AussiePhil

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Want 300 feet runs from your controller? Use Coax
« on: December 08, 2015, 05:38:56 PM »
The following has been tested with the Falcon F16v2 and a modified J1Sys ECG-P2

Pixel type must be a three wire type (no clock wire)

RG59 coax is common and relatively cheap and is a perfectly good long distance medium for pixel data.

I tested this during the year and got 300 feet from quality copper/copper Coax actually that was the length I had so no idea of the maximum distance, then went and bought a cheap roll from ebay forgetting the cheap rubbish uses a copper clad steel centre conductor that has a much higher resistance and therefore less maximum distance though I'm easily getting 100 feet.

Once you going these distances then local power at the pixels would be required anyway so the only requirement is to get data and ground from the controller to the pixels.

The diagram below shows the power being run from the PSU with the controller but in real life you may well have a different supply out in the yard.



I see this as a simple solution to a distance problem rather than use tricky electronic solutions.

Offline Gerry

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Re: Want 300 feet runs from your controller? Use Coax
« Reply #1 on: December 10, 2015, 02:02:12 AM »
Hi Phil,

How can you (or me a layman) tell whether the coax is good quality or not ?

If you had another PSU closer to the lights , would you need to connect the grounds of both of them ?
Gerry

Offline corey872

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Re: Want 300 feet runs from your controller? Use Coax
« Reply #2 on: December 11, 2015, 08:59:42 PM »
I would be curious if you tried without the coax?  Once you get to a 'capable' board... Falcon F16V2's, the uSC, uAmp, Afterburner, etc... they can send data quite a long ways on pretty minimal wire... a strand or two of Cat5, a single wire of the typical "3 core" / RGB wire, etc.  I've usually noted ground line loading is what stops the data reception in those instances, not degradation of the data itself.

In my demo video, I show a uSC running 128 nodes through ~90-100ft of extension cord wire.  The slightly thicker wire gauge helps reduce the ground line loading issues.  But a 'local' power supply helps reduce it even more.  It might be that you could run 300ft to a local power supply just by insuring good grounds and moderately conductive data line of normal wire.
Corey
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Offline AussiePhil

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Re: Want 300 feet runs from your controller? Use Coax
« Reply #3 on: December 15, 2015, 09:48:17 PM »
I have three F16V2 boards, so assume I have "capable" hardware, I understand the output driver stuff etc.

Ground loading? care to explain what you mean in relation to a single wire protocol, ie data with encoded clock.

single wire transmission is easy to model as RF and standard transmission line theory then applies.

Coax is the correct transmission medium for unbalanced signals without the need to implement addition circuitry or resort to baluns for balanced transmission.

As part of all the testing we took a working 70M (210 feet) run from a F16v2 and plugged it into a ECG-P2. This failed to work. Investigations showed that the outputs had been wired with 300R (from memory) resistors that provided a very poor impedance match. Replacing these with 100R to match the F16v2 gave a positive test result.

Cat5/6 has an impedance around 120R and again approximates an impedance match which now doubt goes a long way to explaining the basic success of CAT cabling. The unaddressed/untested issue is sending the data and ground down the balanced twisted pair. This could lead to signal induction into the common ground and potential crosstalk between outputs.
The saving grace will/has been the low level of induction and the relative insensitive input on each pixel.

Whilst Coax definitively has a higher cost in termination time I see it has a hassle free, noise free, long distance transmission path.
 

Offline rcowan

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Re: Want 300 feet runs from your controller? Use Coax
« Reply #4 on: January 20, 2016, 03:51:34 PM »
How do you terminate your connections? I was thinking of terminating with BNC males on both ends of the RG59 and then using something like the attached picture to convert that to two wire that I can connect to the pixels/controller. It would of course be placed in a weatherproof container.
Rick Cowan

Offline pixelpuppy

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Re: Want 300 feet runs from your controller? Use Coax
« Reply #5 on: January 20, 2016, 04:49:53 PM »
Phil  have  you thought about this? It has a pair of 18awg conductors to carry power along with the data over coax.


xLights and Vixen3 for sequencing / FPP for scheduling and playing / Falcon controllers for pixels / DIY controllers for everything else

Offline AussiePhil

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Re: Want 300 feet runs from your controller? Use Coax
« Reply #6 on: January 20, 2016, 04:53:30 PM »
How do you terminate your connections? I was thinking of terminating with BNC males on both ends of the RG59 and then using something like the attached picture to convert that to two wire that I can connect to the pixels/controller. It would of course be placed in a weatherproof container.

I'm a cheapskate and just solder 2 wire pigtails on to the coax and heatshrink the join, will post a couple photo's once my garage is cleaned up so I can work on things again

Offline AussiePhil

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Re: Want 300 feet runs from your controller? Use Coax
« Reply #7 on: January 20, 2016, 05:00:21 PM »
Phil  have  you thought about this? It has a pair of 18awg conductors to carry power along with the data over coax.


I have and for new installs it's a good option if you can get it for a good price, I already have a lot of 18awg or better power cable so apart from neatness it doesn't benefit me.
Now if someone gifts me a roll :)

I'd probably use the power cable to carry 24/28v and dc-dc convert to 5v/12v at the pixel end.

 

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