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, 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. 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. 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. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) After twelve years of therapy my psychiatrist said something that brought tears to my eyes. He said, "No hablo ingles." -- Ronnie Shakes _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev