Concerning my query about what's good enough to count as a contact...
We've done Moonbounce with 3mW (Hobart - Dwingeloo) in JT65 - but a
26m and a 25m dish is stretching 'amateur' a bit again.
Googling for JT65 finds a nice paper:
Message-
Date: Wed, 10 Mar 2010 14:32:33 -0700
From: David Forbes dfor...@dakotacom.net
Subject: Re: [time-nuts] nubie querie
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 4b980ff1.7040...@dakotacom.net
Content-Type: text/plain; charset=ISO
Hal Murray wrote:
Concerning my query about what's good enough to count as a contact...
We've done Moonbounce with 3mW (Hobart - Dwingeloo) in JT65 - but a
26m and a 25m dish is stretching 'amateur' a bit again.
Googling for JT65 finds a nice paper:
mag...@rubidium.dyndns.org said:
Their modulation scheme is 1 of 65 tones. 6 bits per baud.
The extra tone is the synchronizing signal.
6 bits per symbol. 1 baud is 1 symbol per second.
Happy to see someone using baud, just unhappy about seeing it being
used incorrectly.
Thanks for
Hal Murray wrote:
mag...@rubidium.dyndns.org said:
Their modulation scheme is 1 of 65 tones. 6 bits per baud.
The extra tone is the synchronizing signal.
6 bits per symbol. 1 baud is 1 symbol per second.
Happy to see someone using baud, just unhappy about seeing it being
used
the
less! The sticker on the back door of the Landie these days also
confims it. This vehicle may contain nuts
-Original Message-
Date: Wed, 10 Mar 2010 14:32:33 -0700
From: David Forbes dfor...@dakotacom.net
Subject: Re: [time-nuts] nubie querie
To: Discussion of precise time
At 20.33 11/03/2010, you wrote:
I think the Dutch have done EVE; seems something passed by on Moon-Net in
the past year...
Don
AMSAT DL, one year ago, using 6kW CW (injection locked magnetron) on
13 cm and a big parabolic reflector. See
http://www.arrl.org/news/stories/2009/03/31/10738/?nc=1
Hi Jim,
jimlux wrote:
This, and similar impressive accomplishments, has prompted some
lunchtime discussion at work (JPL).. One of us (N5BF) has been
contemplating what it would take to do an amateur EarthVenusEarth (after
some of his experiments doing EME with 5 watts)..
Has recently been
This, and similar impressive accomplishments, has prompted some
lunchtime discussion at work (JPL).. One of us (N5BF) has been
contemplating what it would take to do an amateur EarthVenusEarth
(after some of his experiments doing EME with 5 watts)..
Perhaps a better question is: What is the
Hal Murray wrote:
This, and similar impressive accomplishments, has prompted some
lunchtime discussion at work (JPL).. One of us (N5BF) has been
contemplating what it would take to do an amateur EarthVenusEarth
(after some of his experiments doing EME with 5 watts)..
Perhaps a better question
On 3/10/10, David Forbes dfor...@dakotacom.net wrote:
With regard to the restoration and use of a derelict radio telescope for
amateur radio, that's a fine example of amateurs putting themselves to a big
task and succeeding. I work on radio telescopes, so I know how big a task
that is.
This thread mentioned puilsars and the best clocks. Here are some comments
from those really in the know:
==
Latest Al+ clock comparision at NIST is at better than 10^-17 level see.
http://arxiv.org/abs/0911.4527
==
rich...@karlquist.com said:
I vaguely remember reading that
Hal Murray wrote:
This, and similar impressive accomplishments, has prompted some
lunchtime discussion at work (JPL).. One of us (N5BF) has been
contemplating what it would take to do an amateur EarthVenusEarth
(after some of his experiments doing EME with 5 watts)..
Perhaps a better question
If you like starting from scratch, get a copy of Procedures in
Experimental Physics by John Strong.
-John
===
Hal Murray wrote:
This, and similar impressive accomplishments, has prompted some
lunchtime discussion at work (JPL).. One of us (N5BF) has been
contemplating what it would
J. Forster wrote:
If you like starting from scratch, get a copy of Procedures in
Experimental Physics by John Strong.
-John
And, relevant to the thermal time constant discussion.. That book has a
great section on thermal diffusion and conductivity, along with a chart
of material
jimlux wrote:
J. Forster wrote:
If you like starting from scratch, get a copy of Procedures in
Experimental Physics by John Strong.
-John
And, relevant to the thermal time constant discussion.. That book has a
great section on thermal diffusion and conductivity, along with a chart
of
Paul Boven wrote:
Hi Tom, everyone,
Tom Van Baak wrote:
See: http://www.leapsecond.com/museum/pulsar for some
pulsar ADEV stability plots and links to many research papers
with all the details.
Your page starts with the question if it was possible for an amateur to
receive pulsar signals?.
] On
Behalf Of Tom Van Baak
Sent: Friday, March 05, 2010 1:44 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] nubie querie
In the last slide you show a sand timer. Do you have accuracy data for
it?
Hi Brooke,
The past 3 hours the one hour timer measures 56
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] nubie querie
In the last slide you show a sand timer. Do you have accuracy data for
it?
Hi Brooke,
The past 3 hours the one hour timer measures 56:24,
56:19, and 56:30. That's at 67 F room temp. Somewhere
I
Don Collie jnr wrote:
I`m not sure that questions like these is welcome on this list, but here goes anyway :
1/ What are the the 10 sources of the most constant [invariant] frequencies
known to man, in order of decreacing constancy? Four immediately come to mind.
I vaguely remember reading
Hi
Then there's the phase noise of the pulsar oscillator
-
For a simple crystal oscillator the two word answer might be Leeson's model.
That of course is a cop out since it clearly defines multiple things that
contribute to phase noise.
Bob
On
[mailto:time-nuts-boun...@febo.com] On
Behalf Of Tom Van Baak
Sent: Friday, March 05, 2010 1:44 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] nubie querie
In the last slide you show a sand timer. Do you have accuracy data for
it?
Hi Brooke
The variability will depend on friction between particles and the last
particle's physical slide down the glass!
At 05-03-10, you wrote:
Hi
Even defining when the sand timer is done is not a real simple thing.
Waiting for that very last particle to drop may not be the best approach.
Bob
On
Hi
So can you / do you actually *see* the last grain in the hourglass in question?
If we are looking at something that is not observed in normal operation we
have re-defined the function of the device.
Bob
On Mar 5, 2010, at 10:50 AM, Raj wrote:
The variability will depend on friction
Google USB Hourglass or visit http://home.comcast.net/~hourglass/ and you
will see that it has already been done. His application was as a random
number generator. Should be available as a kit soon...
Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bob Camp
Sent: Friday, March 05, 2010 11:02 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] nubie querie
Hi
So can you / do you actually *see* the last grain
At 10:25 AM -0800 3/4/10, Brooke Clarke wrote:
Hi Tom:
In the last slide you show a sand timer. Do you have accuracy data for it?
Wouldn't that depend on the consistency with which the human flips
the hour glass? They don't flip themselves, you know.
--
--David Forbes, Tucson, AZ
Baak
Subject: Re: [time-nuts] nubie querie
At 10:25 AM -0800 3/4/10, Brooke Clarke wrote:
Hi Tom:
In the last slide you show a sand timer. Do you have accuracy data for it?
Wouldn't that depend on the consistency with which the human flips the hour
glass? They don't flip themselves, you know
Like it very well
On Fri, Mar 5, 2010 at 11:12 AM, Mark Sims hol...@hotmail.com wrote:
Google USB Hourglass or visit http://home.comcast.net/~hourglass/ and
you will see that it has already been done. His application was as a
random number generator. Should be available as a kit soon...
AM 3/5/2010, time-nuts-requ...@febo.com wrote
From: Stan, W1LE stanw...@verizon.net
Subject: Re: [time-nuts] nubie querie
If the time duration of the sand timer is defined as when the first
grain of sand lands
on the bottom, until the last grain of sand lands on the pile of sand on
the bottom
rich...@karlquist.com said:
I vaguely remember reading that pulsars have some fantastic stability
like 1E-20. I don't remember how they established this.
Do you remember how long ago you read that? It might have been some
handwaving back before they had good data.
For a while, the
I vaguely remember reading that pulsars have some fantastic
stability like 1E-20. I don't remember how they established
this.
Rick,
See: http://www.leapsecond.com/museum/pulsar for some
pulsar ADEV stability plots and links to many research papers
with all the details.
/tvb
Even defining when the sand timer is done is not a real
simple thing. Waiting for that very last particle to drop may
not be the best approach.
Bob
Correct. Marking time with an hour glass is not that different
from marking time with a 1PPS. Each signal has a rise time;
one picks the
OK then if you ground up cesium azide and put it in the hour glass wouldn't
you have a cesium clock at much lower cost (And accuracy) then an HP??
Might last quite a while also.
On Fri, Mar 5, 2010 at 1:53 PM, Tom Van Baak t...@leapsecond.com wrote:
Even defining when the sand timer is done is
Hi
A clock and a hazmat site all rolled into one.
Bob
On Mar 5, 2010, at 2:41 PM, paul swed wrote:
OK then if you ground up cesium azide and put it in the hour glass wouldn't
you have a cesium clock at much lower cost (And accuracy) then an HP??
Might last quite a while also.
On Fri,
Plus the effect of a star quake when the crystalline crust rearranges
itself.
Somewhat analogous to a crystal jump.
Bruce
Bob Camp wrote:
Hi
Then there's the phase noise of the pulsar oscillator
-
For a simple crystal oscillator the two word answer
Even defining when the sand timer is done is not a real
simple thing. Waiting for that very last particle to drop may
not be the best approach.
Bob
You could measure of the weight of the hourglass.
Phil
___
time-nuts mailing list --
Eh, does the weight change if the sand runs from top to bottom? Some
quantum mechanic effect I am missing? Or maybe a change in gravity as
the sand drops from high to low?
phil wrote:
Even defining when the sand timer is done is not a real
simple thing. Waiting for that very last particle to
Yes it does due to the variation of gravitational attraction between the
object and the Earth with height above the ground.
However this classical effect is very small and probably virtually
impossible to measure.
Bruce
Gerard PG5G wrote:
Eh, does the weight change if the sand runs from top
Quoth Bruce Griffiths at 2010-03-06 07:58...
Yes it does due to the variation of gravitational attraction between the
object and the Earth with height above the ground.
However this classical effect is very small and probably virtually
impossible to measure.
So, if the mass is closer to the
Matthew Smith wrote:
Quoth Bruce Griffiths at 2010-03-06 07:58...
Yes it does due to the variation of gravitational attraction between the
object and the Earth with height above the ground.
However this classical effect is very small and probably virtually
impossible to measure.
So,
As one who has measured vague things like hourglass time to great
accuracy,
I would suggest finding a robust definition of end of flow.
This would inevitably involve watching the flow past the end of
flow to determine retrospectively
when the flow had effectively ceased.
To be fair to the
On Sat, 06 Mar 2010 08:03:01 +1030, Matthew Smith wrote:
So, if the mass is closer to the centre of the planet, it weighs more?
Never really considered this before, but fascinating nonetheless.
No!
The gravitational attraction will decrease once penetrating the surface.
At the center of gravity
Not to kick sand in your face, but it seems that in order for your automated
turn-over device to work, as well as to accurately measure the time
intervals, you would need a means to determine when the sand quits flowing.
Correct. It's not unlike a zero crossing detector. The period
of the sand
It's all very well to talk about zero-crossing detection in an hour glass,
but you haven't got an oscillator until you have some uniform means to
flip it. Then you can talk about measuring the period (two flips) over
some useful interval.
Seems like the flip should take a second or so. Too fast
I`m not sure that questions like these is welcome on this list, but here goes
anyway :
1/ What are the the 10 sources of the most constant [invariant] frequencies
known to man, in order of decreacing constancy? Four immediately come to mind.
2/ What is the mechanism in an oscillator, that is
: Thursday, March 04, 2010 8:14 AM
To: time-nuts@febo.com
Subject: [time-nuts] nubie querie
I`m not sure that questions like these is welcome on this list, but here
goes anyway :
1/ What are the the 10 sources of the most constant [invariant] frequencies
known to man, in order of decreacing constancy
: Bob Camp
Sent: Thursday, March 04, 2010 11:05 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] nubie querie
Hi
The best answer to the second one is That depends. There are *lots* of
different oscillators out there. Earth - sun, Helium atom floating in space
I`m not sure that questions like these is welcome on this list, but here goes
anyway :
1/ What are the the 10 sources of the most constant [invariant] frequencies known to man, in order of decreacing
constancy? Four immediately come to mind.
2/ What is the mechanism in an oscillator, that is
Hi Tom:
In the last slide you show a sand timer. Do you have accuracy data for it?
Have Fun,
Brooke Clarke
http://www.PRC68.com
Tom Van Baak wrote:
I`m not sure that questions like these is welcome on this list, but
here goes anyway :
1/ What are the the 10 sources of the most constant
In the last slide you show a sand timer. Do you have accuracy data for it?
Hi Brooke,
The past 3 hours the one hour timer measures 56:24,
56:19, and 56:30. That's at 67 F room temp. Somewhere
I have enough clean data to compute the ADEV; it's more
stable than accurate.
It also has a tempco
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