Does the length (resistivity) of an ethernet cable effect transfer speeds?
 

I'll be moving into a dorm room with an ethernet hookup pretty soon, and I don't know where the ethernet jack will be in relation to where I will put my computer. I could wait until the day I move into my dorm and find out, but I don't want to have to make a special trip to some store after I move into college. :/ I'd like to not worry about it and just buy a 10, 12 or 15 foot cord just to make sure I can reach the jack no matter what before I move, but....

I know that the resistance of a wire is proportional to the metal's resistivity, length and inversly proportional to the cross-sectional area. Since all ethernet cables have the same diameter and are made of the same material (...right?), I'm not worrying about those, only the length.

I'm assuming that resistivity effects transfer speeds since some high-speed users claim they can only attain "xkbps" because they are "y" miles or km away from the ISP's server. (Unless of course, they have a fiber optic connection.) Not to mention that the farther a dial-up person goes out into the country, the crappier their connection gets.

Basically, what I'm asking here is.... Will I get a slower speeds, even slightly slower, with say...a 10 or 12 foot ethernet cable instead of a 6 foot one? Or is the difference too negligable - even to downloading and networking software reporting downstream speeds - to even worry about?

Thanks.

well maximum ethernet cable length utp per the spec is 100 yards ( 300 feet). You should not be able to notice any difference in those cable lengths, but you do want to avoid bunching up a long cable or running it very close to EMF emitting devices.

Each switch in the chain restarts the length maximum. They can tell you how your campus hooks to the internet, but the only distance you need to worry about is the distance from the switch to your jack + the distance of cable to your PC

Length won't bother it. I assume you're talking about a coaxial cable, right? Google'd the topic to refresh my memory. I did remember that length didn't bother it, though. Here's a cleaned up snippette I snagged from a website. I cleaned out some useless stuff and clarified where needed:

Coaxial cable is a cable type used to carry radio signals, video signals, measurement signals and data signals. It exists because we can't run open-wire lines near metallic objects or bury it. In other words, trade signal loss for convenience and flexibility. Coaxial cable consists of an insulated ceter conductor which is covered with a shield. The signal is carried between the cable shield and the center conductor. This gives good shielding against noise from outside cable, keeps the signal well inside the cable and keeps cable characteristics stable.

Coaxial cable are usually grouped with the impedance and cable loss. The length has nothing to do with a coaxial cable impedance. For ordinary coaxial cable used at reasonable frequency, the characteristic impedance depends on the dimensions of the inner and outer conductors.

Category 5 cable is not coaxial, its Unshielded Twisted Pair.

Without getting into the hoo-ha of electromagnetics and transmission lines, you will not notice a difference between a 6 foot cable and a 15 foot cable.

Unless you plan on running ethernet cables from your dorm room on the 7th floor to the lobby, don't worry about it.

And Gechmir, he clearly seems to be talking about ethernet cable, which is totally different from coax. :p
(what he^ said)

Yeah, coaxial cable isn't used for ethernet.

Unless some god-forsaken holes still use thinwire ethernet. Dear lord.

o shit. Twisted Pairs. I remember soldering bundles of them (dunno much else about em) ;__; Not much fun... So many wires...

Actually our company makes heavy use of short haul coaxial cable for our gigabit ethernet backbone as many of the runs are too short to use fiber. Most cable company ethernet networks are largely coaxial as well and I'm willing to bet most people use coaxial cable to connect their cable modem to the wall jack.

I'm on a 30 metre CAT5, and it seems to top out at around 8mbytes/sec (around 65mbit). (though, this is sending through a router to a laptop on another 20 metre CAT5).

Still beats wireless.

Ok, but it's not thinwire, and I assume it's not actually used in a configuration with everyone on the same cable, connected with "T"s.

Its probably because coaxial cable acts as a waveguide at high frequences (microwave), and its cheaper than optic fiber waveguides.