My CD player is kaput. I’d like to replace it with a DVD/CD player that hooks up to my stereo and my TV. The TV will be located about 20 feet (7 meters) away.
Question:
Is there a practical limit to the length of the cable that links the DVD player to the TV?
I’m no electrician, and can’t approach your question from a technical perspective, but back when we used coax for network cabling, we certainly had some segments that long.
Well, the coaxial cable running from my satellite dish to one of the receivers is over 50 feet long and I get no interference.
You should be okay.
This page suggests a maximum for composite and S-video cables of around 50 feet. You’ll want to get good quality cable (but don’t fall for that gold-plated connector crap), however, don’t go overboard with those overpriced Monster cables.
In addition to the advice of Q.E.D., should you wish to use coaxial cable, opt for RG/6, not RG/59.
Wow - the homes in your town are really clustered within 30 feet of your local cable office?
Thing to remember about coaxial is that it’s a shielded cable. The outer metal is (ideally) grounded, blocking any transient interference. The wire at the centre of the cable is carrying the signal. It’s a much better cable to carry a long-distance signal than composite or S-Video, though the trade-off is more expense and weight.
My army unit has routinely thrown up 40-foot radio masts, using a coaxial cable to carry the signal from the truck, admittedly with BNC connectors (a quarter-turn locks them in place, as opposed to the screw-on RG cables). One time, we had to string several BNC cables together for an overall length of well over 100 feet and didn’t have a problem, though I’ll admit the audio-only VHF radio imposes somewhat lesser demands than a DVD player.
FYI There is a coaxial cable between Sydney and Melbourne (900km) which was first used to run simultaneous live TV shows at the same time (with split screen!) - I don’t know if it’s still being used now that we have satellites.
You two have both made the mistake of ignoring the presence of intermediate repeaters. If your TV is hung overhead from the light poles, you can see them - aluminum boxes the size of a big lunchbox - every block or so. With the underground coax, the repeaters are much further apart, but they’re still there.
Actually, Desmo, I was simply wryly pointing out that cable can carry broad bandwidth (100 or more channels) hundreds of feet. Yes, there are repeater amps, as you note, but… (“Wow, your town has repeater amps every 30 ft? That’d be 3-6 across the front of every yard. Even the telephone poles aren’t nearly that close.”)
The longest continuous RG-6 cable span in my house (running inside a wall from the basement to the attic and then along the length of the house to my AV room) is ca 100 feet, with no perceptible degradation. Admittedly, it’s quad shielded, but I crimped it myself, which given my fumble fingers should count for a few dB loss.
The first attenuation chart I grabbed (not from my best stuff) shows an attenuation of 4.66 db/100m (303ft) at 55MHz, up to 20.4 dB/100m at 1000MHz. Admittedly, attenuation isn’t the only figure of merit, but it’s probably a useful indicator for anyone who’d ask this question. Lengths of 10 m (30 ft) are no problem. More damage is done to the signal at the cable/connector, connector/connector, and internal connector/PCB interfaces than in 20m of well shielded cable
Is that answer more to your liking?
Yep.