Hi Paul,
Glad I didn't say no aircraft clocks use a 60Hz timebase! I wonder if they used
a commercial (non-aircraft) movement? The design seems to break the normal
aircraft design premise that a single failure should not cause the loss of more
than one duplicated system. Unless the clocks have
Robert Atkinson skrev:
Hi Paul,
Glad I didn't say no aircraft clocks use a 60Hz timebase!
I wonder if they used a commercial (non-aircraft) movement?
The design seems to break the normal aircraft design premise that a single
failure should not cause the loss of more than one duplicated
One comment, and one idea on airflow...
I've noticed that none of my high-end frequency standards use
fans at all. That includes every Rb, Cs, and H-maser. This does
not mean they are all cool to the touch, but my guess is it's better
to allow temperature gradients to exist than use fans in an
Tom Van Baak wrote:
One comment, and one idea on airflow...
I've noticed that none of my high-end frequency standards use
fans at all. That includes every Rb, Cs, and H-maser. This does
not mean they are all cool to the touch, but my guess is it's better
to allow temperature gradients to
At 10:13 AM -0700 5/22/09, Tom Van Baak wrote:
One comment, and one idea on airflow...
I'm sure we could discuss for some time what airflow is too much
or too little or where to place the thermal probes or how to take IR
scans or how then interpret them. But it seems to me the bottom
line is
In message 4267588cdd7544d48a9a119584228...@pc52, Tom Van Baak writes:
I'm sure this requires no small effort in thermal engineering on
their part.
The major part of this effort was to reduce the power usage to
maximize battery lifetime.
The plot you get is then simply accuracy (or jitter or
Excellent Paul! Many thanks for taking the time to prepare this data for
me. I've no idea which variation mine is, but I guess I can assume (for
now) that it doesn't require an external timebase because there's only one
connector on the back.
I'll hook up power and see what happens. As soon as
When I swapped my 5370A AC fans for DC fans I was concerned that the inverter
in the fan motors might have some effect on the performance of the
instrument... after all, it is measuring stuff at the part per trillion level.
I was rather surprised to see that, if anything, the internal
In message blu125-w59049fd49ae9ec2fa1474ce...@phx.gbl, Mark Sims writes:
I was rather surprised to see that, if anything, the internal jitter went
down a couple of picoseconds
That could easily be reduced microphonics in the OCXO because the new
fan does not rattle around as much.
--
rich...@karlquist.com said:
First of all, the 5071A has to be able to run on a battery, so you can
do the flying clock experiment.
Did you have any trouble convincing the airlines and/or FAA that it was safe
to take an atomic clock on a plane?
I'd be more worried about the big batteries than
Hi!
Regarding the comments below on the 5370: there are always two
questions with temperature: meeting spec and reliability. Instruments
vary as to which is a bigger issue. Some have temperature
proof measurement techniques that will work virtually until
something burns up, so you can get
The reason for the fans is to prevent premature failures of the
silicon devices due to thermal degradation. The life of a silicon
chip is halved for every 10C temperature increase, more or less.
I was going to make a similar comment, but got sidetracked poking around
google. I didn't find
Hal Murray skrev:
The reason for the fans is to prevent premature failures of the
silicon devices due to thermal degradation. The life of a silicon
chip is halved for every 10C temperature increase, more or less.
I was going to make a similar comment, but got sidetracked poking around
Hal Murray wrote:
The reason for the fans is to prevent premature failures of the
silicon devices due to thermal degradation. The life of a silicon
chip is halved for every 10C temperature increase, more or less.
I was going to make a similar comment, but got sidetracked poking around
The power dissipated in a modern CPU chip (watts per sq cm) far exceeds that of
a cooking hotplate. There are some videos on YouTube showing CPU's literally
exploding when they loose cooling for just a short time. ECL is a rather
chilly iceberg in comparison...
M. Warner Losh wrote:
In message: 20090522185851.4137db...@ip-64-139-1-69.sjc.megapath.net
Hal Murray hmur...@megapathdsl.net writes:
:
: rich...@karlquist.com said:
: Did you have any trouble convincing the airlines and/or FAA that it was
safe
: to take an atomic clock on a
In message 4a170da2.3080...@rubidium.dyndns.org, Magnus Danielson writes:
Hal Murray skrev:
There are being books written about this. One that I have found being a
fairly short but useful one is the ATT Reliability Manual.
It is worth pointing out that a very large fraction of all electronics
In message 971f24636bd13158d9fe412ec6c9c885.squir...@webmail.sonic.net, Rick
Karlquist writes:
The old photos of Len Cutler watching the airline porters carrying
the clock up the stairs to the plane give the impression that
the airline was honored to be asked to participate.
According to a SAS
On 5/22/09 10:39 AM, Rick Karlquist rich...@karlquist.com wrote:
Considering
Other than that, there is really no way a transformer can
fail. Another thing is that if any fan were used, it would raise
the issue of microphonics in the 10811 oscillator, which is a serious
issue in the
Poul-Henning Kamp skrev:
In message 4a170da2.3080...@rubidium.dyndns.org, Magnus Danielson writes:
Hal Murray skrev:
There are being books written about this. One that I have found being a
fairly short but useful one is the ATT Reliability Manual.
It is worth pointing out that a very large
Mark Sims skrev:
The power dissipated in a modern CPU chip (watts per sq cm) far exceeds that of
a cooking hotplate. There are some videos on YouTube showing CPU's literally
exploding when they loose cooling for just a short time. ECL is a rather
chilly iceberg in comparison...
The
Poul-Henning Kamp wrote:
It is worth pointing out that a very large fraction of all electronics
failures are not semiconductors but electrolytic capacitors.
People are often astonished when I tell them, that a long life
electrolytic capacitor is one which will last one year at its rated
Many failed electrolytic caps on PC motherboards and in PC power supplies can
be traced to a case of industrial espionage gone wrong. Somebody sole the
formula for the caps from a Japanese company and sold it to a competitor. That
competitor allegedly cranked out over a billion of the caps
Fellow Time-nuts,
I acquired myself two TAPR TADD-2 PIC frequency dividers as soon as they
hit the list as orderable. Tonight I had the pleasure of completing the
first one.
For a beginner, this kit should be fairly simple. You need to have some
ability to solder and read resistor and
Another question about the TADD-2 PIC divider : they said on main page the
source code for the pic will be released in open source. Does anyone know if
the code is available somewhere ?
-Message d'origine-
De : time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] De la
part de
Hi Said
I would like to take up your offer at $290 US plus postage to Australia. Let
me know how much and how best to transfer the money to you.
Kind regards
Rex Moncur VK7MO
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of
Hi guys,
the unit is gone already unfortunately :( It went really quick. Will try to
get some more specials for time-nuts in the next months.
Thanks for your interest!
bye,
Said
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