Ah. The falling water goes up illusion.
https://www.youtube.com/watch?v=GBtHeR-hY9Y
-Original Message-
From: time-nuts On Behalf Of ed breya
Sent: Monday, May 14, 2018 2:01 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Anybody have suggestions for time related science fair
projects?
There's a great article out there on the web. It takes a bit of digging, but
the title is "Low voltage, the incompetent ignition source".
They discuss fires on PCBs caused by trace contaminants and dendrite growth. A
PCB with sustained flame is shown, powered by a lithium coin cell.
-Origi
What I remember was a brown or black disc with holes around the perimeter.
I remember a lot of holes.
This was around 1991 or so.
-Original Message-
From: time-nuts On Behalf Of Bruce Griffiths
Sent: Saturday, May 12, 2018 4:39 PM
To: Discussion of precise time and frequency measurement
Measuring the speed of light (Fizeau or Michelson method? Other ways)
I saw a great demo of this at the Exploratorium in SF. They had a long spool
of fiber optic, a disc with holes, and a light source. When static, if the
light shines through the hole in the disc into the fiber, then you can
I've seen wifi location reporting me almost 2000 miles east of where I am.
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"Some of you are to young to remember when Javanese products were considered
junk same storyBert Kehren"
I've lived through Japan, Taiwan, and now China. Who's next? 😊
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want cheap crap, they'll build cheap
crap. You want top quality, they'll build top quality.
On Thursday, February 22, 2018, Van Horn, David <
david.vanh...@backcountryaccess.com> wrote:
> According to the data sheet, it looks pretty well in spec, and the
> part has the
According to the data sheet, it looks pretty well in spec, and the part has
thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
ESD hit maybe?
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In a previous job, I used plastics to "lens" antennas at 2.4 GHz, shaping the
patterns for more desirable results.
XFDTD is a great software package for this application but it is expensive.
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Memory... :)
I've induced the "memory effect" in NIMH cells and Nicad, and lead acid.
Simply charge to the same point, then discharge to the same depth of discharge
about 10x.
In the next cycle, discharge completely and you'll see the bump in pack voltage
where you had discharged to previously
In a former job I designed battery charging systems for NIMH cells.
Some cells will TOLERATE long term trickle, some spec ZERO trickle current.
Get a data sheet and read it.
Violating that spec, or low quality cells can get you a battery pack that will
arbitrarily, and without even being conn
Nicads are still made.
NIMH is not necessarily a drop in. While it will work fine in the short term,
crude chargers that implement constant trickle like C/10 can be (emphasis)
tolerated (/emphasis) by some NIMH cells, and totally out of spec for others.
Modern chargers and NIMH is a good pairi
In the US, I have seen line voltage as low as 70VAC and as high as 145VAC.
That's what I design to.
The power companies say different, but my meters don't lie.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Jeremy Nichols
Sent: Tuesday, December 19, 2
Hmm.. Just a while ago, I watched the heather display on ours go to 12:59:59
and stop...
Still giving me 10 MHz though which is all I really need.
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I have a design rule that I've used for decades: "If it fits, it works, or it
does no harm."
-Original Message-
Why so many connecter types? So you don't cross stuff up.
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One thing I love about them is that you can create odd geometries.
All my ham gear, and generally anything I own that's 12V has APPs in the OC
Races standard.
All lead acid sources are also same.
I could see using a different geometry for lithium batteries and the stuff that
goes with them, and
Wouldn't the low density of helium reduce some mechanical friction?
I realize the motions are small but they are motions.
The "Cousteau effect"? :)
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You can feed in an external AREF, but look at the data sheet for the particular
AVR chip.
One thing which is commonly ignored in Arduino-Land is the I/O pin leakage
current and the maximum source impedance specs.
You are well advised to buffer the voltage you are reading, or make sure the
sourc
For popping off the lid, a few threaded holes in the lid would be nice. Insert
screws and let them push against the body and push the lid off.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of ed breya
Sent: Thursday, May 25, 2017 3:08 PM
To: time-nuts
-- Forwarded message --
From: Van Horn, David
Date: Thu, May 11, 2017 at 4:31 PM
Subject: Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse
To: Discussion of precise time and frequency measurement
There's an excellent article out there on the web called "Low Voltage, the
i
There's an excellent article out there on the web called "Low Voltage, the
incompetent ignition source" I highly recommend a read.
I dealt with a case like this a couple years ago. Failed fet in an H bridge
caused a fault which the brick SMPS picked up as a short, and went into
"hiccup" mode
Milling internally and externally to the perimeter of the board is a price
adder, but is routinely done and not expensive.
I've done round PCBs with large, oddly shaped "round" holes in the middle,
impossible to drill.
I've done PCBs where the outer corners had to be milled to a specific radius
In my design I need 10ppM, and then I divide by 8. Software can't correct for
anything.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Bownes
Sent: Tuesday, March 14, 2017 10:50 AM
To: Discussion of precise time and frequency measurement
Subject:
Probably true for many things. My current design has six crystals, and
exactly none of them could be replaced by an oscillator module.
Power and space considerations mostly.
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ht
the damaged equipment?
On Tue, Jan 3, 2017 at 9:33 PM Van Horn, David <
david.vanh...@backcountryaccess.com> wrote:
> I once had some odd equipment failures which we found out were caused
> by the line voltage being at 142V.
>
> This was in the mid 80's in Costa Mesa CA.
I once had some odd equipment failures which we found out were caused by the
line voltage being at 142V.
This was in the mid 80's in Costa Mesa CA. The tech they sent out told me they
had us on the wrong transformer tap.
Lowest I've seen was 70V in Hawaii, with everyone coming home about 5PM an
Possible, but it should not need that, and the original design didn't include
it.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray
Sent: Wednesday, December 7, 2016 10:35 PM
To: Discussion of precise time and frequency measurement
Cc: hmur...
I did check the circuit through the whole range that it should operate in,
based on component data sheets. No issues.
I also carefully varied the voltage right around where the regulator output is,
to see if there was some very narrow band of sensitivity.
Nothing.
-Original Message-
From
Yes, I hit one of those. I forget the frequency other than around 1 MHz, but it
was pretty warm when it shouldn't have been, and it was several volts amplitude.
This thing I'm chasing is much more subtle.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of
way.
> 2) The oscillation / noise is at a very low level and it’s below your
> test gear’s noise floor
> 3) Testing stops the oscillation
>
> Bob
>
> > On Dec 6, 2016, at 4:24 PM, Van Horn, David backcountryaccess.com> wrote:
> >
> > Lots of discussi
The probes don't seem to affect anything.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Andy
Sent: Wednesday, December 7, 2016 7:56 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Totally unrelated, but..
>
> I loo
se floor
3) Testing stops the oscillation
Bob
> On Dec 6, 2016, at 4:24 PM, Van Horn, David
> wrote:
>
> Lots of discussion on here about low noise regulation so someone may know
> what to look for.
>
> I have a receiver which is getting a lot of interference from so
Lots of discussion on here about low noise regulation so someone may know what
to look for.
I have a receiver which is getting a lot of interference from somewhere.
Antenna disconnected, interference still high.
After much poking around, we found that replacing a voltage regulator with a
slightl
Yes.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glen Hoag
Sent: Monday, December 5, 2016 12:14 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] UCCM GPSDO
94V-0 is a UL flame retardancy test, if I recall correctl
I have, for many years, wished the FCC would get serious on enforcement.
I've dealt with CEOs who said basically "ok, so it's illegal, who's going to
catch us?"
I have on occasion had to physically stop shipments from being made.
If we had enforcement with TEETH then it would be easy to make th
Enforcement.. It would be nice.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Alex Pummer
Sent: Thursday, November 10, 2016 10:39 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Nutty time-nuttery with WWVB
And h
There is a wax which melts at 70F. Phase change stores and releases a lot of
heat.
Somewhat optimistic IMHO
https://www.wired.com/2015/05/table-sucks-heat-lower-ac-bills/
http://www.stacoolvest.com/news/
Technical:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4809117/
_
To be fair here, phone chargers have almost no requirement to be quiet other
than conducted and radiated emissions limits.
It's charging a battery.
As a designer of some fairly quiet SMPS systems, this feels like "look how bad
a family car this tractor is".
_
Perhaps the aliens are replying to our signals, mostly saying "SHUT UP!!!"
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning
Kamp
Sent: Wednesday, July 13, 2016 2:18 AM
To: Discussion of precise time and frequency measurement; Bob Camp
Subjec
Have you tried a 110V shaded pole motor fan? Only 60Hz magnetic noise, no
brushless commutation or brushes.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims
Sent: Wednesday, July 13, 2016 9:50 AM
To: time-nuts@febo.com
Subject: [time-nuts] HP5
>That all assumes you have turned interrupts off for some reason. Common
>reasons could be that you are in another interrupt service routine or that
>you are executing interrupt related code.
>
>Bob
What I saw in their interrupt routine was a "full boat" implementation, pretty
typical for C
O M G..
So I followed the link and saw how they do it.Wow. They write interrupts
like the DMV processes applications. I can only imagine what this looks like on
the PIC, where every instruction takes 4x as many cycles.
All of that pushing and popping is PRECISELY what you need to avoid.
P
p...@heypete.com said:
> I'm a little concerned about the speed at which the pulses need to be
> counted. The 32kHz pulses come in every ~30.5 microseconds, and handling an
> interrupt on an ATmega328 running at 16MHz takes about 5.125 microseconds[1]
Huh?
Instruction cycle time is 62.5nS for a
Amusing story:
Back in high school, Ewa Beach Hawaii, I used to notice that the second hand
on the clocks would sometimes slow significantly. This turned out to be caused
by the man who would later become my father in law.
He ran the steel mill, melting old cars into rebar, which was electri
Using the thunderbolt here.
I only asked because a co-worker spotted the altitude and thought it was
"wrong" for boulder.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims
Sent: Thursday, June 9, 2016 10:56 AM
To: time-nuts@febo.com
Subject: [t
with +/- 10'.
Ok..
Michael Perrett
On Wed, Jun 8, 2016 at 1:33 PM, Van Horn, David <
david.vanh...@backcountryaccess.com> wrote:
>
> I have just installed a Thunderbolt here to get our time and frequency
> equipment all on the same page.
> As I was looking at the display on
n 8, 2016 at 1:33 PM, Van Horn, David <
david.vanh...@backcountryaccess.com> wrote:
>
> I have just installed a Thunderbolt here to get our time and frequency
> equipment all on the same page.
> As I was looking at the display on Lady Heather, I was noticing that
> the GPS
Some of that is probably the difference between the geoid (what your surveyed
maps report height relative to) and the WGS84 ellipsoid (what your GPS reports
heights relative to). At Boulder that difference is only about 15 meters,
though.
Generally with VDOP < 2 and a reasonably modern receiv
I have just installed a Thunderbolt here to get our time and frequency
equipment all on the same page.
As I was looking at the display on Lady Heather, I was noticing that the GPS
altitude seems rather wrong.
We are in Boulder CO, which is nominally 5430' and the antenna is about 20' off
the gr
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