chrisc%gold.gvg.tek.com@RELAY.CS.NET (Chris Christensen) (01/31/91)
In article <9225@uwm.edu> PH408014@brownvm.brown.edu (Tim Johnson) writes: >On this question of shielded cables, twisted pairs, coax, etc.... > >Someone has suggested shielded twisted pair. I think there was also mention ofthree conductor coax, but it was dismissed for cost reasons. > >Will one of you electrical engineers tell me why this is a dumb idea: get some of that standard tinned copper braid, slip it over your coax interconnects, ground it. > >This would seem to give you a shielded coax at nominal cost. > >What do y'all think? > > -Tim It sounds like a lot of work but there is no technical reason not to due it. Except it would be better if you had seperate signal and shielding grounds, ie the earth ground and the signal separate. The grounds should come together at one common point in the system and depending on the grounding structure of the system lower levels of hum may be had by only connecting the shielding ground on one end. While this isn't a detailed molecule level discussion it should be a start. I saw a posting where someone was asking if a particular sound was hum or hiss.... It has been my experience that hiss sounds like hisssssssssss, and hum sounds like humumumumumumumum and buzz (which is a derivative of hum) sounds like buuzuzuzuzuz or buuuuuzuuuzuuuzuuu or uzuzuzuzuzuzuzu or zzzzzzzzzzz and hum usually contains hisssss. Chris Christensen
kim@uunet.UU.NET (Kim Letkeman) (02/01/91)
In article <9225@uwm.edu> PH408014@brownvm.brown.edu (Tim Johnson) writes: | Will one of you electrical engineers tell me | why this is a dumb idea: get some of that | standard tinned copper braid, slip it over | your coax interconnects, ground it. I'm not an EE, but I built a set of interconnects as suggested by IAR perhaps 8 years ago. Basically, connect 300ohm antennae wire to a pair of RCA jacks. The result was ok, in that they sounded better than the el-cheapo manufacturer's. The article also suggested shielding them. I picked up that tinned copper braid and shielded the cables, grounding at one end to the RCA jack. The difference was startling. I suppose that it should work as well with unshielded coax. Kim -- Kim Letkeman kim@Software.Mitel.COM uunet!mitel!spock!kim