Low cost coax connectors

ChairmanOfTheBored hath wroth:

Hmmm.... This one is waxed and meets MIL-T-43435B, Type 1, Finish B, Size 3, whatever that means.

I didn't know lacing cord was still in use. Amazing.

How it's done:

Hmmm...

$110 for non-members. I just bought some toys on eBay so that will have to wait. Section 4.4.2 appears to be on lacing bundles.

Looks like NASA also uses lacing cord. It's mixed in among all the ty-wrap photos:

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

It depends on the type of wax. I think Bee's wax in particular is that which is no longer acceptable.

The running stitch isn't used so much anymore as the single.

Just re-established my cert a couple weeks ago. Our company trains assembler, techs, and engineers, all in the same classes.

It would seem to me that they, in particular, would keep it in use. It is probably lighter than plastic ties, and the flammability is lower.

It's also a bunch easier on the hands (having gotten my fair share of nicks from tie wrap ends that weren't flush cut). Lacing also seems to be "gentler" on the insulation.

Yes, I mentioned the laceration factor earlier.

Automated tie wrap tensioners as well as hand pulls typically are more compressive on outer sheaths, and downright bad for coaxial dielectric spacings, whereas lacing cord doesn't ever really get pulled so tightly as to deform said materials.

I'd have guessed the opposite, given the surface area and tensions involved.

One of the possible causes of the loss of the Apollo 204 crew was lacing cut-through of teflon-insulated wire bundles.

John

And, unlike cable ties, it doesn't break and send the brittle pieces falling into some other gear where they could really cause trouble.

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Regards, Joerg

http://www.analogconsultants.com/

Cable ties get pulled pretty tightly by the automatic tensioner devices in use, as well as when tension is applied by hand. Lacing is supposed to be double wrapped, and the knot always loosens a little as it is being tied off. Time also causes "knot creepage", which, like your gym shoes, causes the lace to loosen a slight bit.

Apollo 204? No. That was Apollo 1, mission AS-204. Many do refer to it as Apollo 204, however... even at NASA (see below).

The mission was on Pad 34-A. The booster was Saturn 1-B. The mission was AS-204. The command module craft name was Spacecraft 012.

The Apollo 1 craft that burned on the launch pad was due to combusting nylon in the gear netting, among other things. There was actually an overpressure breech in the craft which vented opposite the side of the craft the fire started on, all within a few seconds. There were several combustible elements in the craft.

The conclusions have already been made. There is no "possible cause" about it. The systems in that craft had been serviced a number of times. A cable bundle was likely scraped on a passageway. More likely than a cable wrap digging through tough Teflon jackets.

The root cause for the ignition was said to be a pair of pliers that a technician left in the walls of the command module. Between the inner and outer skin. That was one thing I heard. The other was chaffing of a wire bundle during one of several equipment servicings, which led to an arc on the day of the show.

Jeff Liebermann snipped-for-privacy@cruzio.com posted to sci.electronics.design:

Not too sure about that, that is semi-skilled labor intensive.

Prowl around

if you want inexpensive connectors. I use their RCA connectors at 75 MHz. and they work just fine. Can't measure the difference between them and BNC, at least not down as low as 0.1 dB.

Jim

-- "If you think you can, or think you can't, you're right." --Henry Ford

The lacing has a tiny contact area, hence high local pressure, and as you note is applied by hand, with arbitrary tension. A tie-wrap is broad and flat and the tension can be defined by the settings on the wrap tool.

Even better is Panduit.

I wear velcro shoes. I never understood why people would want to keep their shoes on using labor-intensive, unreliable closures.

If NASA can call it Apollo 204, it's good enough for me.

John

What a horrible web site!

John

JosephKK hath wroth:

Agreed. It was difficult to automate. However, it replaced an equally labor intensive crimping operation using a very noisy Amp-o-lectric connector cruncher using various connectors like these:

The tinned coax was adequate, but the quality varied radically depending on who was doing the tinning. After about 1.5 years of trying to control an inherently tricky process, along with increasing production requirements, we went back to the crimped connectors. We never even tried to build a proper robot or outsource the coax cable production. The final blow was when a quality consultant identified such manual labor intensive processes as unacceptable. The PCB's and test fixtures were designed to handle both connector types, so the reversion was fairly painless.

Somewhat later, I proposed various fixtures, fixes, tweaks, and improvements, that I thought might have saved the idea, but nobody was interested.

Today, I suspect that I could automate the process. It really depends on how quickly I could heat and tin the braid without generating a large heat affected zone. With solid Teflon dielectric, that's possible. With polyethylene, it's much more difficult. With foam, forget it.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Something like this?

John

Rich Grise hath wroth:

Nope. I haven't tried it and probably don't need to. I listed why it doesn't work. Two big problems.

1. Stripping and exposing the dielectric BEFORE tinning is going to cause it to melt when dumped into the solder pot. That much I tried and determined it to be a loser.
2. Solder dipping tends to produce a blob of solder at the end of the braid. That has to be trimmed off or it won't slide into a matching receptacle. Therefore, I tin the braid first, and then use the rotary stripper to remove the excess.

I hate to tell you this, but the rotary knife wire stripper has been around since long before Al Gore invented the internet. They come in all sizes ranging from hand held to big production machines. For example:

50 patents found for "rotary wire stripper".

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

I have the "Ideal",

mid-page, gold-colored in the illustration, mine is black.

Sliding detent for RG-58, RG-59, RG-6 cutting depths, but Allen-head adjustable to personal taste.

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave

Agreed. Horrible website...good products...great pricing. Two out of three ain't bad.

Jim

-- "If you think you can, or think you can't, you're right." --Henry Ford

Sure, but if you know them tell them they need a new guy for web design ;-)

Thanks for the info.

--
Regards, Joerg

http://www.analogconsultants.com/

This is worse

Martin