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Re: An unusual Oscilloscope phenomenon



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A couple of times I've been up on Twin Peaks and there was a sharply
defined fog layer below. Only a couple of big buildings poke through,
and a few plumes from power plants and such.

Sometimes the sun gets under the fog at sunrise/sunset. Cool.

ftp://jjlarkin.lmi.net/Kit1.JPG


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CPU clock maybe?

John


Re: An unusual Oscilloscope phenomenon


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Nice. Would be even nicer without the attached city :-)

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Possibly. It even happens in standby power so maybe it's the SMPS in there.

--
Regards, Joerg

http://www.analogconsultants.com /

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Re: An unusual Oscilloscope phenomenon



<snip>

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Wow. You're making me drool.

Re: An unusual Oscilloscope phenomenon



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But a lot of the time we look out the kitchen window and see a wall of
fog.

John


Re: An unusual Oscilloscope phenomenon


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Or a shoot-out ...

Well, not in your neighborhood but we had first-time visitors from
Germany a few years ago, our former neighbors. After two week of west
coast sightseeing they stayed in a ritzy S.F. hotel to see the town
before heading out to us. Shooting right in the lobby there, IIRC a
fatal one. They were quite shaken when they got here.

--
Regards, Joerg

http://www.analogconsultants.com /

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Re: An unusual Oscilloscope phenomenon




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Glen Park is a quiet, bucoloc village on the rim of an actual canyon
with an actual stream. Seven restaurants, one sports bar, one dry
cleaner, fresh-baked bread and pastries, one book store, one public
library. We hear the distant, muffled gunshots from Visitacion Valley
and the gentle roar of Interstate 280; we pretend it's a waterfall.

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Well, didn't they buy a ticket to The Wild West? They can get a lot of
mileage out of the story back at home.

I've never been that close to a human shooting. My sister did shoot
her husband, but he deserved it.

John


Re: An unusual Oscilloscope phenomenon


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Luckily we don't hear shootings, except the occasional rifle shots into
the air out of trucks when the drivers had too much booze on Friday
nights. They don't seem to realize that what goes up also comes down.


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They didn't think it would be this wild. But it can. When I did EMC runs
at CKC near Mariposa a saloon fight broke out. A real one, guys flying
across tables, glass crashing, beer everywhere. All the tourists ran as
fast as they could. And the music kept playing.


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Wow!

--
Regards, Joerg

http://www.analogconsultants.com /

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Re: An unusual Oscilloscope phenomenon



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Really. The local cops showed up and said "don't worry lady, we'll
take care of it." And they did.

John


Re: An unusual Oscilloscope phenomenon


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[...]

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Yikes. He must have been a character, and probably not unknown to them.
With some marriages I wonder how they could hold on that long.

--
Regards, Joerg

http://www.analogconsultants.com /

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Re: An unusual Oscilloscope phenomenon


On Jun 26, 4:15A0%pm, John Larkin
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I got this brilliant idea a few decades ago to watch the 4th of July
fireworks from Twin Peaks. Bad idea. The place is full of yahoos
shooting off their own fireworks. Should a fire break out, you are
screwed.

I did watch the Oakland Hill fire from Twin Peaks. I kid you not,
there was a group singing the Grateful Dead's "Fire on the Mountain",
over and over....

Re: An unusual Oscilloscope phenomenon


On Sat, 27 Jun 2009 21:24:03 -0700 (PDT), " snipped-for-privacy@sushi.com"

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Fireworks are usually silly here. Fizz, boom, a dull flash of color in
the fog.

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The fire was awesome. From Diamond Heights, looking across the bay, it
looked like the whole east side was on fire. Above the Clairemont
Hotel was a huge ball of fire with a black center... it looked like
the Gates of Hell.

John


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Oh come on, there's a huge reservoir up there.

I am amazed by the DIY fireworks at Dolores Park.  Much more fun than the
official shows.

Re: An unusual Oscilloscope phenomenon


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We had this here, yesterday (photo is from last year though), top view
from a friend's deck:

http://goldcountryimages.static.adqic.com/uploads/inline/1213875563_8746.jpg

--
Regards, Joerg

http://www.analogconsultants.com /

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Re: An unusual Oscilloscope phenomenon


On Sun, 28 Jun 2009 15:49:19 -0500, snipped-for-privacy@slack.com (David DiGiacomo)
wrote:

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I used to live on 16th street, across from the mission, when the area
was still a real dump, and cheap... a 3 room flat for $315. Now the
whole area has gotten trendy and expensive, and Dolores Park is a
weekend flesh market. Cool.

Been to The Monk's Kettle? That have 20 exotic beers on tap and make a
different pot pie every day.

But Joseph Schmitt will be shut down soon. Boycott Hershey's!

John


Re: An unusual Oscilloscope phenomenon


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The road can't handle much traffic unles things have changed. I
haven't brought a car to SF in a few years. Too much hassle. I do
recall the official fireworks being more like an  "impressionistic"
painting.

One of the better 4th of July displays I saw was in Las Vegas. I was
at the Paradise Hilton. From the parking garage, you could see their
fireworks and displays all around town. The top level was packed with
people, so I guess this is a common way to watch the events. I'm sure
the Stratosphere is packed for the 4th.

Re: An unusual Oscilloscope phenomenon


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the
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It depends on the shield resistance.  Putting a 1-ohm resistor between
the shield and ground on the Rx end is as good as an open circuit for
ground loop purposes, and should get rid of the antenna problem.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
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Re: An unusual Oscilloscope phenomenon



John Larkin wrote:
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   That's the reason you see lots of six inch wide copper bonding straps
in radio studios. They use one and a half inch straps to connect between
the equipment, and the bonding straps.


--
You can't have a sense of humor, if you have no sense!

Re: An unusual Oscilloscope phenomenon


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Same in this here lab :-)

--
Regards, Joerg

http://www.analogconsultants.com /

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Re: An unusual Oscilloscope phenomenon



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I think half of us are talking about low-noise audio frequencies, and
half of us are talking about RF. The way I heard it, you leave one end
unshielded for audio preamps and stuff, but ground both ends for RF;
I think it has to do with wavelength and, well, propagation
characteristics. Of course, the thing that was drummed into me while
they were teaching me this was "GROUND LOOPS!". :-)

Cheers!
Rich


Re: An unusual Oscilloscope phenomenon



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Audio: if one end of a shield is disconnected, the delta-voltage (60
Hz, RF, esd spikes) between chassis is greater. If the signal is
single-ended, that increases noise directly. If differential, it
increases common-mode noise.

Why would you want to do that?

A 60-Hz (and RF, and ESD) "ground loop" can result from different
boxes being plugged into different outlets which have some 60 Hz
difference voltage (or form a relative antenna for RF.) Connecting the
shield on both ends shorts out some or most of this difference voltage
and REDUCES the effect of the "ground loop" on the signal.

Whoever did the drumming was passing on folklore.

John


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