19 Jan
2011
19 Jan
'11
5:35 a.m.
On Wednesday, January 19, 2011 12:12:05 am Robin Gareus did opine:
Thought someone might like that.
Silver solder, or just silver bearing solder? The latter seems to top out
at about 3% siver in an otherwise eutectic allow, but is a noticeably
stronger solder mechanically that doesn't oxidize near as fast. I don't
use anything else myself but it does raise the iron temps needed by
50-100F, which leads to needing to clean the tips more often.
Real silver solder needs a propane or better torch or a tig for heat and
you use a borax based flux that melts and forms an airtight puddle of
liquid glass over the joint so the oxygen is sealed away from the hot
metal, facilitating a nice clean joint when you feed the silver wire in to
make a 'sweat' joint, like the plumbers do for copper piping. But the
borax should be chipped away and removed once it has cooled as its a bit
lossy at those frequencies. Properly done, you get the 'sweat' started,
and pull it along by moving the heat (it crawls to the heat) until you have
the joint level full of silver but no extra beads sticking out. Don't
apply any more silver than what it takes to just seal the joint. Dry fit
accuracies of less than a 5 thou gap work very well, wider gaps are
correspondingly harder to control. You really need a milling machine to do
wave-guide parts correctly.
Thanks robin
--
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)
You have a deep interest in all that is artistic.
On 01/19/2011 03:39 AM, gene heskett wrote:
Ahh, so, here that is called "conduit" and can be metallic or more likely
in recent years, plastic, glued up just like water pipe and smoother to
pull wires through than the metallic stuff. Both need plenty of "snot" on
the wires for a temp lubricant if going very far, and about 3 bends is
still the limit for one pull run.
On Tuesday, January 18, 2011 09:16:00 pm Robin
Gareus did opine:
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.
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 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.
Keyword there is proper, there is a lot of trash for sale at Radio Shack &
friends.
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.
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. 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.
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.
Yikes. If that ever collapses, it will emp into smoke, and and all
electrical stuff for many meters around it. That, it can be said is NOT a
friendly environment. Even your $15 Casio wrist watch is in danger if you
move too fast in that.
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 :)