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Discussion Starter · #1 ·
Given a choice between the following scenarios, which one would likely result in the best (least-bad?) video quality:


1. Two TVs connected to a HD-DVR using low-end semi-active baluns (powered at the transmitter end, passive at the receiver end, roughly $150/pair) and ~100 feet of solid shielded cat5. Kind of like this one: http://www.pimfg.com/product_detail.asp?part=nva-904-at


2. Same two TVs, except NOW there's a 75' RapidRun cable connecting the HD-DVR to a component video distribution amp in a panel on the second floor, and from there the signals travel the last 35 feet along the wrong kind of RG6 -- copper-clad steel, 60%/40% quad-shield aluminum braid (a.k.a. Carol/General Cable C5785, "Home Depot's Alleged Best").


Put another way, the coax already exists, as does the cat5. It's the wrong kind of coax, and there are 3 because when I originally pulled it, I had enough left over to throw in cable #3 to each room in the hope it might be useful for component video someday. At the time, I didn't realize it was the wrong coax to use for component video


What I'm trying to discern is whether I'd be better off using the wrong coax for the last 35 feet with an ideal 75-foot run of 5-coax RapidRun feeding the distribution amp, or just writing the RG6 off as worthless, pretending it's not even there, and just going with a balun and cat5 from end to end. On one hand, I have coax that can be described as "sub-optimal" at best. On the other hand, I'm under the impression that component-over-cat5 is kind of like satellite broadband -- better than nothing, but worse than just about any alternative.


If the coax is worthless for component video, is it at least useful for SPDIF?
 

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I have atleast a thousand feet of RG6 runs to every room in my house, some runs over 100 feet. I have ZERO issues and I have great HD and digital audio to all rooms.
 

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Quote:
Originally Posted by miamicanes /forum/post/17044039


is it solid copper w/copper braid, or is it copper-covered steel w/40% & 60% braid? The problem in my case is that it's the second kind, not the first kind.

Due to "skin effect" most of the signal (50KHZ to 150MHZ) will be on the top .01 inch or less of the cable (where the copper is) anyway.
 

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Discussion Starter · #5 ·
Hmmm... another thought. I've been reading older posts, and so far I've found one guy who had terrible results, and at least two who've had results they categorized as good, if not great. I can't help but wonder... was signal amplification a factor?


The older posts talk about termination and distance, but one potentially important detail nobody seems to have brought up is whether they were connecting the CCS-RG6-faux-component cables directly to the component outputs on their equipment, or whether they were feeding them from something like the component video distribution amp sold by Radio Shack. Assuming the signal fed to the amp is itself good, it seems pretty obvious that a component video signal that's been amplified by a few db has a lot better chance of making it through a short run of steel-core RG6 without visible degradation than a signal that's already been split internally by the media device 2 or 3 times, and might be fairly low-level to begin with (call it a hunch, but I suspect the innards of a DirecTV, Dish network, or Comcast HD-DVR aren't exactly videophile-quality). At least, since the problem that seems to be brought up the most with CCS cable is signal attenuation.


So far, I haven't seen anything suggesting that steel-core has other problems unique to it that would be harder to deal with, like reflection, standing waves, phase distortion, etc. If attenuation is the only real problem, and it's not a huge problem at short (~35-foot) lengths, that's GOOD news, because there are plenty of cheap, low-tech ways to give signals a small boost before sending them into the cable :)



Any thoughts?
 

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Quote:
Originally Posted by miamicanes /forum/post/17044924


Hmmm... another thought. I've been reading older posts, and so far I've found one guy who had terrible results, and at least two who've had results they categorized as good, if not great. I can't help but wonder... was signal amplification a factor?


The older posts talk about termination and distance, but one potentially important detail nobody seems to have brought up is whether they were connecting the CCS-RG6-faux-component cables directly to the component outputs on their equipment, or whether they were feeding them from something like the component video distribution amp sold by Radio Shack. Assuming the signal fed to the amp is itself good, it seems pretty obvious that a component video signal that's been amplified by a few db has a lot better chance of making it through a short run of steel-core RG6 without visible degradation than a signal that's already been split internally by the media device 2 or 3 times, and might be fairly low-level to begin with (call it a hunch, but I suspect the innards of a DirecTV, Dish network, or Comcast HD-DVR aren't exactly videophile-quality). At least, since the problem that seems to be brought up the most with CCS cable is signal attenuation.


So far, I haven't seen anything suggesting that steel-core has other problems unique to it that would be harder to deal with, like reflection, standing waves, phase distortion, etc. If attenuation is the only real problem, and it's not a huge problem at short (~35-foot) lengths, that's GOOD news, because there are plenty of cheap, low-tech ways to give signals a small boost before sending them into the cable :)



Any thoughts?

I've used steel core coax for HD level video for years, never had a problem with picture. The DC resistance is like 30ohms for a 1000 feet. Unless you need to run power down the line (to a LNB on a sat dish) you will be fine on your short run.


Good steel core cable specs. http://www.alliedelec.com/Images/Pro...E/214-0447.PDF
 

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Quote:
Originally Posted by mntmst /forum/post/17044314


Due to "skin effect" most of the signal (50KHZ to 150MHZ) will be on the top .01 inch or less of the cable (where the copper is) anyway.

I thought component video doesn't run at a high enough frequency for the signal to be carried near the skin, which is why solid copper is recommended for carrying component video signals?
 

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Quote:
Originally Posted by crosen /forum/post/17045949


I thought component video doesn't run at a high enough frequency for the signal to be carried near the skin, which is why solid copper is recommended for carrying component video signals?

Check the effect calculator. Even at 5Mhz (less than even 480i signal bandwidth) there is a major reduction in effective cross-section. http://www.calculatoredge.com/electr...n%20effect.htm


If I were running a few thousand feet, yes I would go solid because of the added DCR of steel core.
 

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Quote:
Originally Posted by mntmst /forum/post/17046071


Check the effect calculator. Even at 5Mhz (less than even 480i signal bandwidth) there is a major reduction in effective cross-section. http://www.calculatoredge.com/electr...n%20effect.htm


If I were running a few thousand feet, yes I would go solid because of the added DCR of steel core.

Thank you - good info. So, I guess it's safe to say that the thickness of the copper cladding is > 34um (the calculated value at 5Mhz, if I'm reading this right.) How can you know the actual thickness of the cladding for a given cable? I generally do not recall seeing this in the provided specs.
 

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Quote:
Originally Posted by crosen /forum/post/17046128


Thank you - good info. So, I guess it's safe to say that the thickness of the copper cladding is > 34um (the calculated value at 5Mhz, if I'm reading this right.) How can you know the actual thickness of the cladding for a given cable? I generally do not recall seeing this in the provided specs.

I've seen specs for large technical projects that require the cladding requirement to be at least 125 um. ASTM B869 - 07 is the actual spec for the cable.
 

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Quote:
Originally Posted by miamicanes /forum/post/17044039


is it solid copper w/copper braid, or is it copper-covered steel w/40% & 60% braid? The problem in my case is that it's the second kind, not the first kind.

I have not checked in 3 years. I just know its RG6.
 
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