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coaxial cabl vs RCA cable

10K views 89 replies 15 participants last post by  CruelInventions 
#1 ·
Hi Team,


want to buy VSX-323-K model, but my concern is that can I provide input audio from another room(away from 30feet) by coaxial cable (or only RCA audio cable required). 2nd, for output can I use coaxial cable (30 feet) for bathroom (without amplifier) without any qauality comromize.

Thanks in Advance.
 
#2 ·
Technically there's no such thing as 'RCA cable'. The plugs are RCA. Interconnect cables using RCA plugs are often called RCA cables, but that's a misnomer, they're correctly referred to coaxial cables with RCA terminations. Line level signals can be run to 100 feet with no ill effect.
 
#3 ·
Actually, as in factually; not all cables that are terminated with RCA connections are coaxial, but are more prominently a variant of common multi-conductor cables, such 18/2, 20/2, 22/2 with a common drain, with or without shielding.

However, in the context of video cable, RG 59, & RG 6 are most prevalent in residential applications.

In digital audio transmissions RG 6 is standard.

In analog audio multi conductors are standard.

The voltage drop is based in the signal type, gauge and wire type...

At 100 feet, losses will be experienced in all of the aforementioned variables.

At 30 feet digital audio over RG6 won't be problematic, however, analog audio will suffer, from an audiophile perspective, but not a distributed audio perspective.

Analog video at 30 feet, over RG 6 or 59 won't suffer massive losses.
 
#7 ·
my concern is that can I provide input audio from another room(away from 30feet) by coaxial cable (or only RCA audio cable required).
We are assuming that you mean digital (probably SPDIF) when you say "input audio by coaxial cable" and that you mean line level analog audio when you say "RCA audio cable required". Either of these are possible - without too much technical discussion, cable capacitance and shielding are going to be your biggest issues and can be overcome with a quality cable (depending on how much high frequency fidelity you expect).

Read this web page for pretty good layman explaination: http://www.bluejeanscable.com/store/audio/index.htm

2nd, for output can I use coaxial cable (30 feet) for bathroom (without amplifier) without any qauality comromize.
An output "without amplifier" sounds like you are trying to drive a speaker from the amplifier of your AVR - is that correct? In that case, of course you would want to use a thicker gauge of speaker wire like 14awg - that would work fine. If you are outputting a line level analog signal for the bathroom that will use a separate amplifier (or amplified speakers), use the same type of cable as above.
 
#29 ·
Near as i can tell the only relevant remaining spec for rg6 is 18 gauge conductor. Given that the belden pdf did not on quick review mention rg6 and states the conductor is 24 gauge if somebody calls it mini rg6 it is very loose marketingspeak. All 75 ohm cable is not rg6. Similarities between some non rg6 cable and and something meeting the rg6 spec does not make it rg6. Aiui, over 90percent of my dna is identical to that of a rat. I am not a rat and rats are not human despite significsnt similarities in our dna. See?
 
#31 ·
Perhaps it would behoove us all, if you read every word of the spec document and then went on to visit other such vendors specifications of the same cable type. They can all pass AES or SPDIF...

Its about bandwidth, which is the product of more then the gauge of a cables primary conductor. The a cables egression and permitted ingressions (current requirements aside); the smaller the primary conductor or conductors can be.

Solid core Cat5E can pass it all! As can stranded Cat5 E, or higher! As an easily verifiable fact, mogmai, monster, canare, belden, west penn, delco, whirlwind and others that I cannot recall at this moment all make multi-stranded, multi-conductor, twisted pair, AES/EBU digital audio cables. Which can be terminated to any TS or TRS connector in the world!

Have a look: http://www.mogamicable.com/category/bulk/dig_interface/aes_ebu/ be sure to scroll down the page and read everything, and the debate should com to an end.

Please stop talking about rats and DNA and read the spec, or look up others. Or remain in the dark, but please stop injecting false truths into this thread, as it may actually mislead some members and onlookers, from outside the body of membership.

I am right and everyone else that has posted in opposition to me, is wrong!:kiss:
 
#35 ·
Belden showed up on the 3rd page for me?

http://www.belden.com/docs/upload/np198.pdf
No where on that page does it mention RG6

RG6 is a general term, which defines a minimum class of analog and digital performances.
No, it isn't. It's a specific type of 75 Ohm coax cable.

I think you're too arrogant to admit that you really don't have much of a clue.
 
#42 ·
The switch to RG6x was made in part, if not largely, due to the larger center conductor. It does a better job of providing power to dish-mounted LNA/LNBs. RG79x ruled before that. Specs are virtually identical. Different flavors of each use different dielectrics. Never heard of "mini" RG6. Not sure what the RG6 debate has to do with the original question, but that's life in Internet Fora-ville.
 
#44 ·
I'd have to check my references for detailed specs. Most satellite systems spec'd RG6 partly for the extra DC current-carrying capacity for the dish-mounted amplifier. Power is/was routed from the box inside the house to the amplifier on the external dish. There are a few other construction differences. You are free to believe what you want, or ask another RF engineer. Cable delivery systems are not my specialty; I was given that information a long time ago by a buddy who designed them.
 
#46 · (Edited)
The geometries and dielectrics were changed to accommodate carrier frequencies up 2.4 GHz, over the 1GHz stable utilization of RG59 variants.

DC was and remains a secondary consideration. 13/18 VDC respectively with 300 to 500mA draw. All consumer grade LNB's are fused at 1 amp DC... so current is truly a non-factor...

Like I said, in post #32 , it's time to stop guessing, making things up and speaking in just general terms about very specific statements, questions and technologies, in general.

Moving forward, I will correct everyone with acute detail until everyone gets on board or steps-off!

Don, I know that you know your stuff, and that this is merely a clumsy series of posting from you. And I will add that you qualified your position as to warn that you may be incorrect... My point is if you don't know, for sure, don't chime in; especially when a thread is at the edge of boiling over!
 
#45 ·
For those of whom that are having difficulty understanding the central theme of my activities and postings within this thread, they were made abundantly clear in POST #32 .

I encourage all to read it, or re-read it, before commenting further. If after doing so, you still fail to understand, then that's where you will stand, as the rest of us move on.

Glimmie, this goes double for you! And I have no idea who you have confused me with, when you stated:
"BTW, what ever happened to that big amplifier shootout you were going to do over a month ago and show us all how it's done right? How's that coming?"

If I have made such a promise and have failed to deliver, I apologize, as I have clearly forgotten about it, but... I don't recall making such a promise!

Perhaps you can provide us all with a link?
 
#47 · (Edited)
I stand corrected. RG59, not RG79, is what I had in mind (I was recently looking at RG79 for another application as it has half the capacitance of RG59/RG6 and it was not for a matched environment). RG6 does indeed have much less loss at higher frequencies. The cables I use in my work target much higher frequency so it's been a while, foggy memory. Having been put in my place by Garidy I shall bow out.

p.s. A quick look at current Belden products shows 23 AWG center for RG79, 18 AWG for RG6, so my buddy was probably correct.
 
#48 ·
I stand corrected. RG59, not RG79, is what I had in mind (I was recently looking at RG79 for another application as it has half the capacitance of RG59/RG6 and it was not for a matched environment). RG6 does indeed have much less loss at higher frequencies. The cables I use in my work target much higher frequency so it's been a while, foggy memory. Having been put in my place by Garidy I shall bow out.

p.s. A quick look at current Belden products shows 23 AWG center for RG79, 18 AWG for RG6, so my buddy was probably correct.
Don please accept my apology. I was feeling somewhat incensed by Glimmie, and it seems those feelings infected my last few postings (I am only human). I am aware of your back ground and who you are, and I, by no means have the same level of understandings, with regards RF, as a whole that you do.

Please accept my untoward push back.:eek:
 
#49 · (Edited)
RE: The DC DBS cable issue:

The DC issue with DBS antennas was over the use of copper clad steel RG6 and distances of over 100 feet. Copper clad steel RG6 is very popular in the CATV industry as it is physically stronger when used as lead in from the pole to a building. As there was nothing of interest below approx 40mhz on cable systems, skin effect was used to it's advantage in this application. However the copper clad steel starts to provide significant resistance to the DC power up to the dish LNB on even routine runs.

As for RG59, DBS antennas use L-Band as the first IF frequency. That's approx 1200 to 1400 mhz. This is pushing it for standard RG59. Newer digital video RG59 types such as Belden 1505 would be OK but they cost more than generic RG6. And as the CATV industry already uses so much RG6, it's just easier and cheaper for the DBS guys to go along.
 
#50 ·
The DC issue with DBS antennas was over the use of copper clad steel RG6 and distances of over 100 feet. Copper clad steel RG6 is very popular in the CATV industry as it is physically stronger when used as lead in from the pole to a building. As there was nothing of interest below approx 40mhz on cable systems, skin effect was used to it's advantage in this application. However the copper clad steel starts to provide significant resistance to the DC power up to the dish LNB on even routine runs.

As for RG59, DBS antennas use L-Band as the first IF frequency. That's approx 1200 to 1400 mhz. This is pushing it for standard RG59. Newer digital video RG59 types such as Belden 1505 would be OK but they cost more than generic RG6. And as the CATV industry already uses so much RG6, it's just easier and cheaper for the DBS guys to go along.
True story!:)
 
#52 · (Edited)
There's no such thing as "mini RG-6". Any company which uses such a term is using marketing speak.


The central conductor and dielectric thickness dimensions are very specific and you can't shrink them without altering the 75 ohm impedance, yet still use the standard PE insulator every RG6 does, although the shielding outer thickness can differ; the shielding can be beefed up to "quad shielding", for instance. Any shrinking of the conductor or dielectric size, shrinking to make it "mini" also makes it no longer RG-6.


Here's the regular, not quad sheilded RG-6/U variety:

Quad shielded, RG-6/UQ has four shields, of course, so the overall outer jacket if thicker but the wire's internal structure under the shielding is the same.
 
#56 ·
The central conductor and dielectric thickness dimensions are very specific and you can't shrink them without altering the 75 ohm impedance...
That is not correct. The characteristic impedance of a cable depends not only on the dielectric thickness but its dielectric constant. The latter is a property of the material used for the insulation between the center conductor and the shield. Change that and you change the impedance. This is why you can get wildly different sized capacitors for the exact same capacitor value because their construction material differs. Here is the formula:



"k" is the parameter I described.
 
#55 · (Edited)
Indeed I should; as we all should, which was and remains my primary point in the exercise...

Others are clearly coming alongside, yet you prefer to missed the point and sling mud instead, and it seems that Bill likes your behavior, so this suggest to me that we will see similar comments from Bill as well.;)

A Quote from Bill: " Technically there's no such thing as 'RCA cable'. The plugs are RCA. Interconnect cables using RCA plugs are often called RCA cables, but that's a misnomer, they're correctly referred to coaxial cables with RCA terminations. Line level signals can be run to 100 feet with no ill effect. "

I guess that we should all prepare for more Cheese!
 
#54 ·
Re. RG79: It is a rather odd-ball cable, 125 ohm impedance, but only ~10 pF C' instead of the typical ~21 pF C' for RG59/RG6/etc. IIRC! I was using it for the lower capacitance and had it in mind so mistakenly typed that instead of RG59. RG79 targets applications other than video (CCTV/CATV) and standard (50-ohm) RF.

There are small 75-ohm cables but they are not RG6. AFAIK. As I , and others, have said it is not something I have thought a lot about lately.

We laid out several $k for a couple of Gore or Microcoax cables (forget which); wonder how they'd sound in my stereo? :) Of course they are nowhere near as expensive as some of the audiophile cables around. Heck, even our reference $1200 (each) mmW connectors (no cable, just the connectors) pale in comparison to the cost of some speaker cables. Chances are the speaker cables don't sound as good at 50+ GHz, however.
 
#57 ·
amirm is correct about impedence.

As an example, I used a lot of different types of 50 ohm cable in my two way radio work. The bottom line was"The bigger the cable, the less the loss".

His comment on capacitor's size also should of also mentioned voltage rating.
 
#59 · (Edited)
There's no such thing as "mini RG6". Proving there are other cables with 75 ohm impedance which are thinner gauge, such as RG59, proves nothing. The differences, such as RG6's lower signal loss per foot, which can be key in long runs, are outlined here:
http://sewelldirect.com/articles/rg59-or-rg6.aspx
 
#60 ·
There's no such thing as "mini RG6". Proving there are other cables with 75 ohm impedance which are thinner, such as RG59, proves nothing. The differences, such as signal loss which can be key in long runs, are outlined here:
http://sewelldirect.com/articles/rg59-or-rg6.aspx
Wow that was a fast reply...

Fair enough, lets agree to disagree then!:)

Just one strange occurrence however, millions of feet are shipped daily of RG6 U75 Mini Coax. I don't know how to explain the existence of all of the suppliers that are claiming to sell it... Another great AVS mystery I guess?:confused:
 
#65 ·
I know that you guys are having a grand old time, but the OP hasn't seen a single one of your posts after reading my reply six days ago.

 
#68 ·
Bill F is correct. The OP simply wanted to know if he could run a signal 30 feet.
 
#72 ·
Reductio ad absurdum:

Here's an example of scaling coax dimensions. Both are 50 ohm coaxes (I know we're talking 75 ohm in the thread).

The first is 5" in diameter, signal loss is .021dB/100' @ 10MHz, DC resistance of the inner is .1 ohms/1Kft.
The second is .017" in diameter, signal loss is 5.5dB/100' @ 10MHz, DC resistance of the inner is 27 ohms/1Kft.

Both have the same characteristic impedance, both are designed to carry signals well into the RF range, both would perform well for the OP's audio application, neither is the right choice for cost and ease of installation reasons.

http://www.eriinc.com/Catalog/Transmission-Line/Components-and-Accessories/HJ9HP-50.aspx

http://wire-cable-tubing.wireandcab...wg-micro-miniature-coaxial-cables/w-4269-3254
 
#74 ·
Remember this?

1. He's not mentioning a digital connection, he said "audio" (speakers in his other posts)
2. He's talking about coax cable "without amplifier" (possibly line level audio? Might it already be installed?)
3. He's never replied to this thread or any other, in fact, has only 3 posts total
4. He's asked roughly the same question in three separate threads, never responded to any of them

Did he get his question answered? Did he get overwhelmed? Scared off? Embarassed?

This particular thread demonstrates the "butterfly effect" pretty well. Not so much helpful as a massive demonstration of how smart we all think we are, and how we think of each other as dumb. I know that's what AVS is all about, just seems pointless in the "long shot".
 
#79 ·
Remember this?

1. He's not mentioning a digital connection, he said "audio" (speakers in his other posts)
2. He's talking about coax cable "without amplifier" (possibly line level audio? Might it already be installed?)
3. He's never replied to this thread or any other, in fact, has only 3 posts total
4. He's asked roughly the same question in three separate threads, never responded to any of them

Did he get his question answered? Did he get overwhelmed? Scared off? Embarassed?

This particular thread demonstrates the "butterfly effect" pretty well. Not so much helpful as a massive demonstration of how smart we all think we are, and how we think of each other as dumb. I know that's what AVS is all about, just seems pointless in the "long shot".
Shame on all of us! Shame on me - double... I completely agree!
 
#82 ·
As Garidy said, it's time to move on. The OP simply wanted to run a signal 30 feet. The context of his original question suggested he first needed to be shown what coaxial and RCA cable was, in which Bill F explained. More attention should of been paid to finding out exactly what he was trying to do. The OP is long gone. His reasons for no longer responding can be many.
 
#83 ·
Right, but the thread has evolved into a much deeper discussion as many do. This is an exchange of information. Just because the OP had his question answered is not an excuse to have incomplete and misinformation posted for the benefit of those who wish to learn more.

I do understand however how some posters would like to see this post die. But unless it's deleted by the moderator it stands for the history of AVS at least. And since there has been little if any poor behavior in this thread, it will probably be left to stand. So we might as well get it right for the benefit of the future.
 
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