On 01/19/2011 03:39 AM, gene heskett wrote: > On Tuesday, January 18, 2011 09:16:00 pm Robin Gareus did opine: > >> Hi Joern, >> >> If it is an option: use Leerrohre (DE for "empty tubes" ?) to make it >> future-proof, rather than to rely on cable-standards. In a few years you >> may want to replace coax with optical or whatever. > > I think that would translate to wave-guides in English
nope. I mean tubes like pipes in the wall or floor that allow one to easily replace cables that run inside those tubes. It'd still be a major re-wiring task but at least one can change the wires easily compared to in-wall mounted cables. Some trivial mechanical suggestion for a future-proof studio (not an electrical one) at least if future > 10 years and esp. if you don't want to rip the whole studio apart for major renovation. but wave-guides are a good drift. > but check your > sizes, at 3Ghz, they are hundreds of times greater cross sectional area > than a coax would be. Also, a lot less loss if properly terminated. 250 > feet of it has less loss than 3 feet of this mini-coax in common use now, > but you would have at least $20k in that 250 feet too. > > In short, optical seems the best way to go. I helped setup a fiber link > several years ago that was 39 kilometers long, and the end to end optical > loss was 0.5 db. You can't do that with wave-guide or a G-Line, and coax > would have likely been 60-80db of loss and much less bandwidth, we stuffed > 4 television channels though that fiber. > >> The only question I can answer is #4: The problem is reflections caused >> by skin-effect if you do solder them. Back in the days that I spent in >> the physics dept. we used solder-less crimp connectors for everything >> high-freq. > > I can't testify about 3Gb+ solder joints, but I do know that properly done, > they are invisible at .6 Ghz. You may have to putz with it a bit, but it > CAN be done. sure, one question is if it can be done by Joern and another is if shelling out more euros for a proper crimp-on connectors is worth not to worry about possible bad solder joints. > And, I have yet to see a physics prof that actually knew which end of the > iron got hot, let alone could actually make a good joint. Too many have > the attitude that their hands do not fit the tools and make no effort to > teach themselves how to do it. LOL. This was/is experimental physics in cooperation with hardware-informatics. Eventually we designed custom ASICs and did the PCBs and soldering of the prototypes ourself, pretty much everything is non-standard since it must be able to work in a >5 Tesla magnetic field. It is currently running inside the ALICE detector @LHC. > I will allow the comment that when fabricating wave-guide parts and filters > for 7Ghz work, which I have done a few of decades ago, those were usually > silver soldered because the regular tin/lead solders surfaces oxidized with > time much worse, screwing with the skin effect losses. Silver oxide may > look fugly, but is still a pretty fair conductor when frequencies are in > the realm where skin effect reigns supreme. Just as true inside the wave- > guide as it is on the skin of a coax conductor. > interesting. I do remember a drawer with at least 15 different kind of solder. Now I know what that silver stuff in there was in there for :) Cheers! robin _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev