AVL@MATH.AMS.COM (Al Lazzareschi) (10/12/89)
While we are on the subject would someone like to comment on
the difference between RG58 and RG59 thinwire?
Can you mix them or should you use just one type?
Allan Lazzareschi American Mathematical Society
Technical Specialist P O Box 6248
AVL@MATH.AMS.COM Providence, R.I. 02940
(401)272-9500 x272
-------mep@AQUA.WHOI.EDU (Michael E. Pare) (10/13/89)
>...difference between RG58 and RG59 thinwire?
RG58 is based on a nominal impedence of 50 ohms and can range from 50 to 53
ohms. To use it for thinnet applications you need to ensure the type you
buy is rated at 50 ohms. RG59 is based on a nominal impedence of 75 ohms
and is more often used for CATV (broadband) applications. The two should
never be mixed. bob@JVNCB.CSC.ORG (Bob Albrightson) (10/13/89)
> While we are on the subject would someone like to comment on > the difference between RG58 and RG59 thinwire? > > Can you mix them or should you use just one type? No. RG58 is 50 ohms and RG59 is 75 ohms. You don't want to use RG59 at all in an ethernet installation. ( I assume that you are refering to ethernet ). -bob
mhw@wittsend.lbp.harris.com (Michael H. Warfield (Mike)) (10/14/89)
In article <624204828.0.AVL@MATH.AMS.COM> AVL@MATH.AMS.COM (Al Lazzareschi) writes: >While we are on the subject would someone like to comment on >the difference between RG58 and RG59 thinwire? RG58 is 50 ohms impedance. That is what is generally used for "Thinwire ethernet". RG59 is 75 ohm cable and CANNOT be used for ethernet. I understand some people may have gotten away with it bu their transcievers must be extremely forgiving (most are not). In any case, if it works at all it is WAY out of spec. IEEE spec is 50 ohms +- 1%. >Can you mix them or should you use just one type? Don't mix. Only use RG58. Michael H. Warfield (The Mad Wizard) | gatech.edu!galbp!wittsend!mhw (404) 270-2123 / 270-2098 | mhw@wittsend.LBP.HARRIS.COM An optimist believes we live in the best of all possible worlds. A pessimist is sure of it!
karl@asylum.SF.CA.US (Karl Auerbach) (10/14/89)
In article <624204828.0.AVL@MATH.AMS.COM> AVL@MATH.AMS.COM (Al Lazzareschi) writes: >While we are on the subject would someone like to comment on >the difference between RG58 and RG59 thinwire? I was one of the folks who installed the network at Interop last week. We had lots of thick, thin, and this year, unshielded twisted pair (not to mention non-ethers such as fddi, IBM type 1 [for token ring], etc). Clearly, thin ether is easier to handle than thick, but its run length is more limited. It's a mild pain to attach end-connectors on either type, but you need more of 'em on cheapernet (thin). I've never had noise problems with either, but I've had more shorts with thin than with thick. But compared to thin and thick -- twisted pair is wonderful -- once you get the connectors right. Modular jacks don't fall out like those hideous AUI connectors [even when the slide locks work], a mere mortal can carry the wire, and you don't have to be a Vanderbilt to pay for it. You *do* end up with a star (or star of star, or spine and ribs) shaped network, with sometimes more total cable. But with the right kind of wiring discipline (using all those things that the phone companies invented when they were in the telephone business -- like punch down blocks and wire closets) twisted pair can make life much easier and potentially less expensive. --karl--
BEAME@McMaster.CA (10/16/89)
> RG58 is based on a nominal impedence of 50 ohms and can range from 50 to 53 > ohms. To use it for thinnet applications you need to ensure the type you > buy is rated at 50 ohms. We had someone who shall remain nameless (he dosen't work at here anymore), wire several areas with 53 ohm RG58. Does anyone know what the ramifications of this are ? We are mostly running 3C501 :-( cards in PCs. - Carl Beame@McMaster.CA
pat@hprnd.HP.COM (Pat Thaler) (10/17/89)
> / hprnd:comp.protocols.tcp-ip / BEAME@McMaster.CA / 10:18 am Oct 15, 1989 / > > > RG58 is based on a nominal impedence of 50 ohms and can range from 50 to 53 > > ohms. To use it for thinnet applications you need to ensure the type you > > buy is rated at 50 ohms. > > We had someone who shall remain nameless (he dosen't work at here anymore), > wire several areas with 53 ohm RG58. Does anyone know what the ramifications > of this are ? We are mostly running 3C501 :-( cards in PCs. > > - Carl > Beame@McMaster.CA > ---------- The 802.3 10BASE2 specification for the average coax characteristic impedance is 50 +- 2 ohms and impedance variations of +- 3 ohms sinusoidal centered around that value are allowed. (50 ohms +- 1% is the spec for the terminator.) If your actual impedance is 53 ohms, you are slightly out of spec. If your impedance is 53 ohms nominal with variation a few ohms to either side you are a little further out of spec. If your wire is all 53 ohm, you probably won't see problems (but if you see problems, it may be hard to say whether it is the wire or the other networking products.) If you have a mix of 53 and 50 ohm wire (perhaps 53 ohm wired in the walls and 50 ohm cables from the wall to the station), there will be extra reflections which could cause high bit error rates (CRC and alignment errors). Pat Thaler