glen@aecom.YU.EDU (Glen M. Marianko) (02/24/89)
I have been trying to figure out what is the true-to-spec thin-ethernet cable and get different answers from various cable and data-comm vendors. Some prescribe the use of stock RG58A/U cable, or even RG58C/U, saying things like "we use it all the time with no problems." However, some vendors sell a different and "thinner" in outer-diameter cable than stock RG58A/C. Belden is one (stock# 9907). To the eye, besides the o.d. difference, there is an extra skin-tight ground-shield around the plastic insulator that protects the center stranded conductor. Also, the Belden is not as flexible as the RG, probably because of this shield. Personally, I prefer the RG for its flexability and easier installation of the BNC connector (with the Belden you have to knife-strip away that extra ground from the insulator to reduce the possibility of a short to the pin crimped to the center conductor). Also, the off-the-shelf coax cable strippers don't expect the smaller OD of the Belden thin, and therefore don't strip the layers away as well. Not to mention, the BNCs themselves which require different size crimps because of the o.d. change (on the belden I wind up using BNCs intended for the thinner o.d. of teflon plenum cable). So... what's up here? Does it matter much which you use, especially in long-length situations where you really want to get the maximum length out of the spec. On the surface, the manufacturers seem to quote a higher picofarad-capacitance per foot than the genuine thin stuff, although they all claim to be within the thin-ethernet specs. Anyone know for sure what these specs are and the real life implications? -- Glen Marianko, Albert Einstein College of Medicine glen@aecom.yu.edu