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Isola microwave laminate...

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server

Guest
On Thu, 22 Oct 2020 14:13:00 -0700, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:

I only needed 3 square inches, but they sampled me a full panel. Good,
I\'ll have some around for fast protos.

https://www.dropbox.com/sh/fva424mq477k857/AACy1-4WS7yddHNOKpeg3w4Fa?dl=0

This is much better than FR4, and the board houses say it handles like
FR4.
The TDRs show a big capacitive bump (downward blip) at each of the SMA
connectors, which I\'m guessing is the capacitance from the center pin
to the ground legs on top, and maybe the connector itself. These are
$1.85 connectors. The fix is to cut away some of the ground plane on
the bottom side.

https://www.dropbox.com/sh/az755ssl8bsx8qo/AABk-OWfpipJuw2Iz-3F1kKca?dl=0

It\'s a little more complex on a 4-layer board. We used the ATLC field
solver to work that one out.





--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
B

Bill Sloman

Guest
On Tuesday, October 27, 2020 at 1:03:50 PM UTC+11, jla...@highlandsniptechnology.com wrote:
On Mon, 26 Oct 2020 16:32:35 -0700 (PDT), Flyguy
soar2...@yahoo.com> wrote:

On Saturday, October 24, 2020 at 8:49:23 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 24 Oct 2020 11:37:41 +0200, Piotr Wyderski
pete...@neverland.mil> wrote:

John Larkin wrote:

I was just talking to Miguel about this: nobody wants to do analog
design any more, and the guys in the big companies who used to do it
have mostly retired. More biz for us, I guess.

Somebody still designs the multi-GHz scopes and remaining gear. One example:

https://www.keysight.com/en/pdx-2948607-pn-UXR0404A/infiniium-uxr-series-oscilloscope-40-ghz-4-channels?nid=-31885.1251400&cc=PL&lc=eng

Best regards, Piotr

I wonder if the 110 GHz version costs a million dollars.

Sure, some outfits are doing heavy-duty electronic design, but I think
there are fewer analog/circuit designers than there were. One of my
EEs is a recent grad and he says that his classmates avoided analog
electronics. They all want to type code, as in c or python or verilog.

Just my impression. I don\'t have serious statistics, just some
personal anecdotes.

No, you are right. I mentored a group of seniors in EE and they could not solder. I asked how do you get thru an EE program w/o learning how to solder. They responded that all of their circuits were simulated. If only you could sell simulated products...

I did a walkthrough of the Cornell EE school. I counted about 35
computer screens and one oscilloscope screen.

Laptops are cheaper than lab benches, especially when the students
have to pay for their own laptops.

What they are not acquiring is instincts.
Bizarre claim. In any event what they should be acquiring is in-depth understanding - which let\'s them explicitly test their ideas in more ways than just slapping a circuit together.

--
Bill Sloman, Sydney
 
F

Flyguy

Guest
On Monday, October 26, 2020 at 6:39:40 PM UTC-7, Bill Sloman wrote:
On Tuesday, October 27, 2020 at 10:28:06 AM UTC+11, Flyguy wrote:
On Friday, October 23, 2020 at 2:49:05 AM UTC-7, Bill Sloman wrote:
On Friday, October 23, 2020 at 3:31:15 PM UTC+11, Flyguy wrote:
On Thursday, October 22, 2020 at 6:53:24 PM UTC-7, Bill Sloman wrote:
On Friday, October 23, 2020 at 9:59:31 AM UTC+11, John Larkin wrote:
On Thu, 22 Oct 2020 18:45:21 -0400, Phil Hobbs
pcdhSpamM...@electrooptical.net> wrote:

On 2020-10-22 18:09, John Larkin wrote:
On Thu, 22 Oct 2020 17:51:10 -0400, Phil Hobbs
pcdhSpamM...@electrooptical.net> wrote:

On 2020-10-22 17:13, John Larkin wrote:

snip

Crossover, using RF/microwave specified parts in time domain, is
special fun. Let\'s not tell anyone that it\'s possible.

I did some of that around 1984, in Cambridge, UK. Word has finally reached California?

Come to think of it

Ghiggino, K.P., Phillips, D., and Sloman, A.W. \"Nanosecond pulse stretcher\",Journal of Physics E: Scientific Instruments, 12, 686-687 (1979).

used a BFT95 5GHz broadband transistor in a simple emitter-coupled monostable. I was working in west London at the time, but it was for a group at the University of
Southampton.

John Larkin is trying to shut the stable door forty years after the horse had bolted.

Hey SL0W MAN, you just can\'t RESIST posting ad-hominem bullshit about John

What makes you think he is human?

That is the sort of bullshit that separates you from polite society. You need to crawl out of your hole, turn off your computer and socialize with people.

John Larkin admits that he can\'t do the regular social interactions that distinguish humans from other anthropoid apes. He doesn\'t fit into polite society.

Neither does Flyguy. I rest my case.

--
SL0W MAN, Sydney
LOL! You spend TWENTY HOURS a day in front of your computer!! Furthermore, you admit to falling asleep during meetings with people that BORE YOU!!! Note: that ISN\'T socializing.
 
P

Przemek Klosowski

Guest
On Sat, 24 Oct 2020 13:09:38 -0700, jlarkin wrote:

Sabine does not approve.


She does has a point. Spending a bunch of billions to discover nothing
sounds like it\'s motivated by the spending.
We have to be careful with what we mean by \'discovering nothing\':
Michelson-Morley interferometer failed to discover ether, and resulted in
fantastic progress in science. The FCC @ CERN pitch claims that not
finding certain types of dark matter particles will push the theory
forward.
I am not arguing for or against it---just saying that \'negative result\'
may also be helpful. It is true, though, that projects have to compete
and be seen as \'zero sum\' to a degree, i.e. doing FCC will have the
opportunity cost for other projects.

The problem with these big-science projects, from a business or from a
career standpoint, is that they get built in one big shot, and then they
are done. You can hope that there will be another big project to jump
to, but that\'s risky.
Many of my university friends were on SuperColider, and when that
collapsed, were snapped by the Wall Street in mid-nineties to do
financial modeling, which they were very good at, but the assumptions
were from the old school finance guys, so it blew up in 2008. Maybe it
would have been cheaper to spend the SuperCollider money to keep them
employed there :)
 
J

Jeroen Belleman

Guest
On 2020-11-01 22:36, Przemek Klosowski wrote:
On Sat, 24 Oct 2020 13:09:38 -0700, jlarkin wrote:

Sabine does not approve.


She does has a point. Spending a bunch of billions to discover nothing
sounds like it\'s motivated by the spending.

We have to be careful with what we mean by \'discovering nothing\':
[Snip]


[Finance] blew up in 2008. Maybe it
would have been cheaper to spend the SuperCollider money to keep them
employed there :)
Now there\'s a thought!

Jeroen Belleman
 
S

server

Guest
On Sun, 1 Nov 2020 21:36:43 -0000 (UTC), Przemek Klosowski
<przemek@tux.dot.org> wrote:

On Sat, 24 Oct 2020 13:09:38 -0700, jlarkin wrote:

Sabine does not approve.


She does has a point. Spending a bunch of billions to discover nothing
sounds like it\'s motivated by the spending.

We have to be careful with what we mean by \'discovering nothing\':
Michelson-Morley interferometer failed to discover ether, and resulted in
fantastic progress in science. The FCC @ CERN pitch claims that not
finding certain types of dark matter particles will push the theory
forward.
I am not arguing for or against it---just saying that \'negative result\'
may also be helpful. It is true, though, that projects have to compete
and be seen as \'zero sum\' to a degree, i.e. doing FCC will have the
opportunity cost for other projects.


The problem with these big-science projects, from a business or from a
career standpoint, is that they get built in one big shot, and then they
are done. You can hope that there will be another big project to jump
to, but that\'s risky.

Many of my university friends were on SuperColider, and when that
collapsed, were snapped by the Wall Street in mid-nineties to do
financial modeling, which they were very good at, but the assumptions
were from the old school finance guys, so it blew up in 2008. Maybe it
would have been cheaper to spend the SuperCollider money to keep them
employed there :)
I designed the cryo instrumentation for the SSC helium plant in
Waxahatchie, which was finished. I also did microsteppers for tuning
the cavities, which CEBAF used too.

The big-labs business is mostly gone, along with a bunch of small
companies that made stuff for them.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
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