but the LPRO isn't designed (well, according to the spec) for GND != -VE
So long as you don't introduce it to real ground (i.e. isolate it), it won't
know that the -12V is floating below world ground :-)
Dave
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Morning Stanley,
Good news! As I mentioned before, I am happy to act as a UK Post
Office if youl'd like to send all the UK-bound boards to me. I am
collaborating with Ian Muir in Wales (Time Nut member Gonzo) on this
project, so between us we would like five boards please. If you can
let
On 07/21/2010 10:11 AM, David C. Partridge wrote:
but the LPRO isn't designed (well, according to the spec) for GND != -VE
So long as you don't introduce it to real ground (i.e. isolate it), it won't
know that the -12V is floating below world ground :-)
Doable, but surely chassi ground of
An udpate for everyone,
I am STILL waiting for Stackpole Electronics thin film resistors which I
ordered through Digikey.
I have kicked Stackpole, but current delivery date promised is mid August.
Regards,
David Partridge
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time-nuts mailing
The parts are all coming in and the boards aren't far either, so I'll reiterate
my previous offer of programming the PICs.
If you already have your PIC(s), you can send them to me with a self-addressed
envelope and I'll program them no charge.
or
I have six PICs left from a recent purchase
Hi,
I noticed in several circuits that the 10MHz isolation transformer in
input and output circuits have a 6.8nF or 10nF capacitor to GND. How
necessary is this for suppression of unwanted signals? Is the
transformer itself not sufficient? I would expect common mode issues to
be a bit worse with
Hi
The cap likely improves the VHF stability of the circuit.
Bob
On Jul 21, 2010, at 7:46 AM, Joop wrote:
Hi,
I noticed in several circuits that the 10MHz isolation transformer in
input and output circuits have a 6.8nF or 10nF capacitor to GND. How
necessary is this for suppression of
Peter,
Thank you for offering to help, don't send paypal yet, I will send you the
boards then after we know your postal expense then we can do the paypal thing.
Stanley
- Original Message
From: Peter Vince pvi...@theiet.org
To: Discussion of precise time and frequency
Its to prevent 'earth loops' and avoid issues with DC and low
frequency AC on the coax screen - usually its found only on tx or rx
end- not both- depends on the installation which practice is followed.
Telcos tend to solid ground at the send end and cap ground at the rx
end. And yes- it can
Please pardon the blatent plug, but this is a rare one. I've just listed a
Rockwell PLGR II dual frequency GPS on ebay. Search for item No. 260638851411
Thanks,
Robert G8RPI.
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Ground is chassis ground as far as I remember, and the LPRO was bolted
straight on the chassis.
RobK
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: 21 July 2010 10:52 AM
To: Discussion of precise time and
...and according to the post from Greg Dowd (who was on the design team at
Datum), it had a 24V PSU as an add on for the option.
Rob K
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: 21 July 2010 10:52 AM
To:
In which case if the lpro needs +24, then use a buck-boost 12-24V DC-DC
converter.
Regards,
David Partridge
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf
Of Rob Kimberley
Sent: 21 July 2010 16:08
To: 'Discussion of precise time and
My first email from yesterday I think got rejected or put in queue because I
tried to attach a picture... Hopefully this will make
it through.
I *think* the Rb model had a slightly different top panel (judging from the few
pictures I've seen)... Probably made to either
absorb some of the heat
Am still looking for an Efratom MGPS manual... copy, scan... or anything at all
on it. Would be nice to know how to make use of the RS-232 connection on this
GPS receiver!!!
Thanks!
Mark
Sent from my iPhone
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time-nuts mailing list --
So, do we now have available, an up to date (a moving target with Mouser, I
acknowledge) parts list and stock numbers for correct resistors(trim),
FETs, and ICs?
Lester B Veenstra MØYCM K1YCM
les...@veenstras.com
m0...@veenstras.com
k1...@veenstras.com
US Postal Address:
PSC 45 Box 781
APO
Are you sure? I honestly thought we just bolted it in the 1U chassis. I know
earlier Datum units with the larger FRS Rbs went into 2U chassis.
Rob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Greg Dowd
Sent: 20 July 2010 6:20 PM
To:
Hi guys,
for those of you that have Jackson Labs Technologies, Inc. products we
have placed the latest firmware updates onto our web-site under the support
tab:
_http://www.jackson-labs.com/support.html_
(http://www.jackson-labs.com/support.html)
This has been the first update since
The problem is straight forward, except for sensing the position of the
pendulum so the impulse is applied at the correct phase.
There must be a bunch of published designs, but if I were to try it, I'd
use something optical or capacitive.
For optical, I'd put a annular ring of IR
On 07/22/2010 02:13 AM, Morris Odell wrote:
Hi all,
I have been asked to help with the construction of a Foucault pendulum. This
is a long pendulum which oscillates in a slow stately fashion in a fixed
plane which appears to move as the earth rotates. In reality the surrounding
environment is
At 08:13 PM 7/21/2010, Morris Odell wrote...
Has anyone here had any experience with such a system of have any
suggestions regarding the sustaining system? This is an interesting
and
challenging project.
Scientific American, back in June 1958, covered many details of
Foucault pendulums,
Hi
If you use the mechanical system (raise and lower the pivot point): Can you use
the strain on the pivot to get the location information?
Bob
On Jul 21, 2010, at 8:53 PM, Mike S wrote:
At 08:13 PM 7/21/2010, Morris Odell wrote...
Has anyone here had any experience with such a system of
... Foucault pendulum ...
Has anyone here had any experience with such a system of have any
suggestions regarding the sustaining system? This is an interesting and
challenging project.
Several years ago, I found a web site for a commercial place that made them
for museums. (I forget why
On 7/21/2010 7:13 PM, Morris Odell wrote:
Hi all,
I have been asked to help with the construction of a Foucault pendulum. This
is a long pendulum which oscillates in a slow stately fashion in a fixed
plane which appears to move as the earth rotates. In reality the surrounding
environment is
Griffith Park in LA operates a Foucault pendulum that's been going for at
least 70 years (don't ask how I know). They might have a writeup
somewhere. I think te pivot was a simple clamp holding the piano wire.
You'd think it would fail from stress, but the pendulum is very long, so
the angle of
Hal Murray wrote:
Several years ago, I found a web site for a commercial place that made them
for museums. (I forget why I was looking for that sort of stuff.) You might
find interesting stuff/ideas via google but I didn't find a similar site with
a bit of searching.
The Museum of
The Museum of Science and Industry in Chicago had one when
I lived there in the 1960's.
You lived at the Museum of Science and Industry? :)
Sorry, couldn't resist. But, you actually can live there for a month:
http://www.msichicago.org/matm/
Randy.
There is at least one in DC, at the Smithsonian iirc.
RPI, where I went to college, had one in the 3 story stairwell in the
library. Don't know if it is still there.
I remember one someplace in London too.
Someone mentioned temperature compensation. What would you need to
compensate for? Temp
Well, Morris, this does sound interesting.
You've had some pretty conventional replies, so let's up the ante a bit.
If you need to know where something macroscopic is in space, attach a GPS
receiver to it. Then program some PIC device (lots of advice about that on
this list) to compute optimum
Silly me, I just realized you need to compensate for the change in
length with temperature.
This sounds like a great project!
On Wed, Jul 21, 2010 at 10:26 PM, Bob Bownes bow...@gmail.com wrote:
There is at least one in DC, at the Smithsonian iirc.
RPI, where I went to college, had one in
bow...@gmail.com said:
Silly me, I just realized you need to compensate for the change in length
with temperature.
It depends...
If your setup to replace the energy is PLLed to the pendulum position it
doesn't need to know the period. (at least not very accurately)
--
These are my
I remember one someplace in London too.
Science Museum in South Kensington, I'd expect, but I've not been there
20+ years.
-John
Someone mentioned temperature compensation. What would you need to
compensate for? Temp change in the wire wouldn't effect the rotation
as far as I can tell.
[snip]
The bob on a Foucault pendulum is usually quite massive, so there's no
reason
why it can't be inexpensive lead-acid batteries that are recharged by
solar cells.
IMO, there is no reason to put anything active on the bob.
I'm sure you'd save money over mechanisms to move the pivot or
These turned out to be made by Fairchild.
If you expressed a desire to purchase one or more of these chips, I'll
be contacting you soon with total cost. If you have a preference for
packaging, please send me a note. Some evidently prefer the small flat
rate box, although I'd planned to ship
I'm considering buying a rubidium standard, not that I really need one,
just because I'm a Time Nut. I have some questions on what to look for
and what to watch out for. I'll probably get one from either fluke.l or
flyingbest on ePay.
I know that they wear out. Is there any model I should
J. Forster wrote:
The problem is straight forward, except for sensing the position of the
pendulum so the impulse is applied at the correct phase.
There must be a bunch of published designs, but if I were to try it, I'd
use something optical or capacitive.
For optical, I'd put a annular ring
Joop,
The cap is isolate any DC from the transformer, The manual for TADD-1 has
this iformation at the TAPR site has this manual
http://www.tapr.org/~n8ur/TADD-1_Manual.pdf.
On Wed, Jul 21st, 2010 at 9:46 PM, Joop l...@xs4all.nl wrote:
Hi,
I noticed in several circuits that the 10MHz
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