1 ohm transmission line

Nice. Thanks.

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John Larkin                  Highland Technology Inc 
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John Larkin
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  • That is the best approach; make it double-sided for use as a transmission line - one side ground, the other signal. According to my ITT Reference Data for Radio Engineers 4th ed, pg
597, the chart shows a one inch wide strip over ground plane gives about 10 ohms standard FR4. So, with 0.006 mil Kapton(TM) dielectric the thickness being one-tenth should yield 1/10 the Z, and the higher dielectric constant should give (guessing) another factor of two. I could not find any reference to use of two parallel flat lines as a transmission line, but the Z should not be much higher than the classical microstrip; that is where use of Kapton(TM) as you suggested will "compensate" over G6 (FR4) dielectric. You should see rise times in the picoseconds region.

feet

Reply to
Robert Baer

for

the

feet

  • This construction looks superior, the "newer" one looks crappy and will give a rather large impedance discontinuity at their bad connectors.
  • No waste; keep the unused part for a different-length line. For Z testing, make a 2nSec long line like i mentioned; the physical length may surprise you.
Reply to
Robert Baer

Incwww.highlandtechnology.com jlarkin at highlandtechnology dot com

There is shielded ribbon cable off the shelf that one could use for the many-cables-in-parallel construction case. Sloppier risetime WRT the flex construction case.

Reply to
Robert Baer

Page 591.

Reply to
John S

This all reminds me of laminated power busses used to distribute DC on a circuit card - alternating layers of copper and thin dielectric, with odd layers carrying one side and even layers the other side. Wonder what the characteristic impedance is?

Here is one vendor of many:

Joe Gwinn

Reply to
Joe Gwinn

[...]

energy

True, it's awkward. But you have to make the pulse comes out of there with gusto and then any other way would require large widths, on account of the skin effect.

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Regards, Joerg 

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Reply to
Joerg

energy

This whole flex thing is interesting. I have another application where I want to pipe a fast (like, 5 GHz) differential analog signal a foot or two over a small flex. I won't get serious about that for another month or two, but it would be interesting to characterize the 1 ohm line, and the signal application, as regards HF losses. I'll post if I find anything interesting.

The PDF link Glen posted is great, but dosn't talk about high frequency things.

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John Larkin                  Highland Technology Inc 
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John Larkin

How about conventional line driving transmission line transformer to load...

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bloggs.fredbloggs.fred

feet

How about using Amphenol 151-2831-050 (or -040) shielded flat cable; (100 foot spools)?

Reply to
Robert Baer

when a powerline fell into the street here, and the fuses never blew it melted parts of the street (concrete and asphalt) into pretty green glass like in that photo.

Reply to
Cydrome Leader

At the old house we had one of those events. One of those trailer type dump trucks arrives at a neighbor's to dump 20 Ton of crushed granite. Starts backing up while raising the dump-trailer. Before I can scream from across the street it snags the 7200V overhead feeder line in the alley. Hot end whips all around like a bull-whip, igniting fences and making "purty" bits of blue-green glass from the grit in the alley ;-)

Surprised me. It never did blow a breaker. APS had to come out and poke it open manually with a pole. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
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Jim Thompson

I think they call those clinkers! ;)

Jamie

Reply to
Jamie

The wire was doing some sort of dance from damage it left. Part of it hit a puddle, which just blew water and rocks all over the place. I'm not sure what caused it fall in the first place. I wonder what the physics are of why those cables whip around like they do.

Reply to
Cydrome Leader

JxB :-) When I was doing MHD technician work at MIT Building 20, when we'd fire the shocktube, dumping ~30,000 Amps, every wire in the building responded ;-) ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Jim Thompson

Have you ever been to the Francis Bitter magnet lab at MIT? I read some book about research done there and how they were able to shake the entire building by shorting out generators into Bitter solenoids. Clamping down the cables was supposed to be a big deal as well.

I made a magneformer to do quarter crushing. Only the solenoids exploded and vaporized, and none of the wiring jumped around past that.

Reply to
Cydrome Leader

I

That was just barely beginning when I graduated. Initially they were running in the middle of the night relying on the fact that old-town Cambridge had DC power. In the middle of the night they'd short it out >:-}

Then they got their own AC motors spinning up big DC generators, de-clutch and dump into a shorted turn.

Sorta of what we were doing MHD style.

{:-} ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
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Jim Thompson

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