Cable Lengths

Posted: Wed Apr 02, 2008 9:45 pm

Does anyone know a website that has information on Cables, Maximum lengths and when and how to boost signals. I misplaced one of my books that has this information. I'm looking for audiovisual style cables like:

RGB
XLR
TRS
VGA
BNC
Cat5
RG6
RS-232
Etc, Etc.

Thanks in Advance.

RO Admin Joined: Mar 20, 2000 Posts: 4262 Location: Canada

calling cucco

Posted: Thu Apr 03, 2008 12:47 pm

I must not be the only one who doesn't know.

Posted: Thu Apr 03, 2008 1:49 pm

Cable manufacturers provide specs for their cables. Check out Belden's web site. Specs for similar type cable made by other manufacturers should by similar.

Posted: Thu Apr 03, 2008 2:17 pm

Here's the problem with answering that question -

For audio/video transmission, it's not as simple as providing a straight "328 feet" answer (which, BTW, is the max recommended for CAT5 though I've seen runs going twice that distance.)

For A/V, you have to bear in mind that ALL cables behave differently and you're mainly looking at the resistance and the capacitance of each cable and the impact that these will have on the signal. Then you have to determine how much of this impact you are willing to accept as your maximum fault tolerance.

With analog signals, which degrade gracefully, you can get quite a bit of distance, but again, is completely dependent on too many variables to list here.

With a digital cable, you may also get great distances, but in general, they do not fail as gracefully. Meaning that if you start to introduce mass amounts of jitter or begin to lose bits due to distance, then your signal may become unusable.

In other words, there is no simple answer.

What I would suggest is to tell us a specific use of a cable and the preferred distance for that cable and we'll let you know if it's possible or even recommended.

BTW - the list you gave:

RGB
XLR
TRS
VGA
BNC
Cat5
RG6
RS-232

Only a few of those are cable types. VGA (arguably), CAT5(e), and RG6 are the only cables you specified. All others are connectors and do not specifically relate to any particular cable.

Also, some connectors, such as XLR/TRS, or BNC/VGA/RS232 are utilized on similar or identical cable types.

For example, a BNC connector may be used on RG6, VGA, and RGB signals.

Also, XLR/TRS are used (typically) with balanced audio lines. With balanced audio, there are a few questions -
1 - Is there 48V being applied? (Generally, I've found that the 48V DC current can not run as much of a distance as the lower voltage signals generated by the mic. This is another function of Graceful Degradation. As 48V degrades, the capsule no longer retains its bias correctly and thus begins to distort or become noisy. Whereas a signal of only 1.8V or so returning from the mic may loose some of that which will affect some of the frequencies, but you will still get a potentially usable signal with maybe some artifacts to the sound.)

As already suggested, checking individual vendors' pages may provide a lot of insight into what you're looking for.

Cheers-

Jeremy

Posted: Thu Apr 03, 2008 9:52 pm

I'm so glad people like you frequent this site. Thanks.

Posted: Fri Apr 04, 2008 4:47 am

used analog video on BNC over great distance
Horse Racing Broadcast
Football Ground Broadcast
Golf Courses are BIG

same goes for balanced audio ... AND even at Mic levels
500 metres ... ?? +
1 Km even

Digital video SDI is not so far 250metre and then things get bad
bad or well abused cable and HD can get bad over only 60metres ... even 30metres

I've sent VGA across a building on a good cable ... 30 metres +
perhaps further

RS232 not so far but 422 big distance

as Cucco said
there isn't a single correct answer here
and we have all used cables beyond spec

abuse cables and you probably won't get specified results

Posted: Fri Apr 04, 2008 6:16 am

At least you don't have to run long power lines...
Wireless Extension!
I only noticed this after April Fool's though, not sure when it first went up. And I dunno how much power it beams.

Use fibre optics for digital, IIRC unless you want to run a cable to somewhere crazy like Jupiter the signal loss is zero.

Posted: Fri Apr 04, 2008 8:20 am

Not necessarily.

Fiber optic has a couple different standards - mainly the connector types and the fiber material.

The different connectors definitely make a difference since the standard TOSLINK is known for having slight gaps between the sending/receiving device and the cable itself.

Additionally, glass fiber cables are far more capable of maintaining their signal over long runs than poly/plastic stranded. Then of course, you have to question how many strands, etc...

The problem is, the best transmission medium for optical would be glass. Not only is this horribly expensive, all it takes is one dumbass to step on your cable and you're out a LOT of money.

AES is still the best means for carrying digital signals as it's resistant to interference (RF/EM) and still quite robust.

I've personally taken AES signals in excess of 500 feet (about 160 meters) without any problems.

J

Posted: Fri Apr 04, 2008 4:21 pm

similar distances for HD video over optics

there are tougher cables for use on studio floors and OBs
cameras are now on optics and the install cables may have camera power seperate but on the studio floor the optics and power are contained in the one sheath

this all requires a specific termination method and equipment
at this stage this is all expensive but getting cheaper and will be normal in years to come
... very, very soon
the connectors on the end will also become general knowledge but for now
ST SC ... FC ... and others with protective flaps and doors
single band
multi band
is probable all a bit of a mistery to most

DON'T look into the ends of these PRO optic cables because the laser IS dangerous to eyes.
... this is not TOSLINK or ADAT stuff

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