Not surprising at all.
It's called an Orrery (After the Earl of Orrery, I believe) and it's not all
that hard to do, especially if you approximate with circular orbits and don't
try to do ALL the moons or deal with the rotation of the planet itself.
Getting within a fraction of a percent is prob
On 11/3/14, 1:50 PM, Tom Van Baak wrote:
I have a question about that. If I understand correctly, recent IAU
resolutions have decoupled the definition of the SI second from the
terrestrial geoid, which is too fuzzy to be used for a definition. Instead
the geoid potential is held fixed by (or de
On 11/6/14, 5:08 PM, Scott McGrath wrote:
The only problem with these standards is the tube availability since they have
that neat little rom which allows the standard to recognize the tube.
So using available non-5071 tubes is a challenge unless someone solved the
rom issue
But the first
On 11/8/14, 6:58 PM, Pete Lancashire wrote:
Is this who you got it from
http://www.css-timemachines.com/
if so, why not contact them ?
http://www.css-design.com/downloads/TM1000A_Manual.pdf
page 9 of the pdf.
___
time-nuts mailing list -- time-n
On 11/14/14, 4:28 AM, Bob Camp wrote:
Hi
The question kind of is: Is it really supposed to be 60kHz and slightly
off frequency? Or is it deliberately at that frequency because it's a
multiple/submultimple of something useful?
It could easily be a switcher in somebody’s video gear. Keeping
I'm sure someone here has fooled with the Si570.
I just got a few of them (CMOS output), and am about to deadbug one of
them to fool with it (unless there's some convenient protoboard out
there available.. I didn't look too long and hard, but some casual
googling didn't find one).
Looking at A
On 11/18/14, 8:04 AM, paul swed wrote:
I just picked up the si5351a and the thing that jumps out at mee is the 228
registers to program.
Granted it lets you create just about any frequency and there is a good
program that tells you what to set the registers to. But 228 registers is a
lot.
The tra
On 11/18/14, 10:24 AM, Götz Romahn wrote:
Jim,
thre is some info at:
http://www.box73.de/product_info.php?products_id=1869
it's all in German. If you can read that, goto "Zusaztinformationen"
(additional informations) where you will find a comprehensive articel
(pdf-document) also in German langu
On 11/18/14, 11:19 AM, Orin Eman wrote:
I have one of these: http://sdr-kits.net/PA0KLT_Description.html
built with the CML output Si570 that goes to 1417 MHz (!)
There is a schematic in the assembly manual that's linked to from that
page. They use 100n and 1n capacitors in parallel on Vdd and
On 11/19/14, 3:59 PM, Dave Daniel wrote:
I remember the "Fast and Damn Fast Buffer Amp" data sheet. LH0036? I may
not be remembering the correct part number. I used to have a copy of
that data sheet, as well as another that was labeled "DC to Daylight" on
the data sheet.
DaveD
On 11/19/2014 2:
On 11/19/14, 9:17 PM, Magnus Danielson wrote:
Hi Rick,
They did not mention the complexity of the laser system they needed,
especially considering that the optical bench of a fountain isn't all
that small, and also because they want to de-tune lasers. While they
seems to have an idea, they didn'
19, 2014, at 9:00 PM, Jim Lux wrote:
Interesting parts.. They aren't kidding when they say you need good
power supply bypassing and decoupling.(a comment that is in the 84
book but not the 75 version) I'm trying to remember what I was
using them for: driving a YIG tuning coil in a p
I'm writing a short simulation program to generate samples from a analog
system with some op amps, etc., and I'm wondering if anyone has some
practical experience on picking parameters for the generator.
I'm generating minutes worth of data sampled at 1 kHz, and my opamps
have their flicker/wh
On 11/23/14, 7:21 AM, Magnus Danielson wrote:
Jim,
Find myself providing guidance in both the 2010 and 2013 threads, and
they are still valid starting-points.
For music synthesizer applications, flicker noise have been done, such
as on this schematic:
https://rubidium.dyndns.org/~magnus/synths/
On 11/23/14, 11:15 AM, Alex Pummer wrote:
by us in central California, we get 1kW/h square meter average around
the year, the south even more, el Cajon will have today +29C° in the
afternoon as of 23 of November 2014
I suspect more like the insolation peaks at 1kW/square meter or a bit
more,
On 11/23/14, 5:46 PM, Brooke Clarke wrote:
Hi Jim:
It turns out that ground water that's being pumped is very similar to
pumping oil. It's a limited resource.
There's a web page showing the GRACE satellite maps of California and
that we are running out of ground water.
Back east where that da
On 11/24/14, 2:20 AM, Graham wrote:
Interesting.
I have also been thinking that it might not be too difficult to
implement using Beaglebone Black, Raspberry PI, or even one or another
flavour of Arduino. Lots of possibilities from simple to not so simple.
The challenge is always trying to fi
On 11/24/14, 6:05 AM, Mark Kahrs wrote:
For those who are interested, a relevant dissertation can be found here:
http://dspace.mit.edu/bitstream/handle/1721.1/71453/795174737.pdf
Unfortunately, you can't print it, but you can read it. A rather complete
discussion of the construction of the exp
Started plotting some sampled data from my experimental system, and
interestingly, it seems to have a 1/f^2 slope, rather than a 1/f slope.
I had expected the amplifier noise to dominate, but perhaps one of the
myriad other noise sources is contributing as well (e.g. sample clock
jitter, ADC q
On 11/26/14, 1:37 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
Said mentioned on an earlier thread that if a GPS antenna is used
outside, lightening protection should be used. This immediately
reminded me of something that happened about 10 years ago to me
1) Lightening damaged my ADSL mod
On 11/26/14, 2:00 PM, Martin A Flynn wrote:
The N2MO station has an external GPS antenna on the gable end of the
building. It's connected to the polyphaser arrestor with FSJ4-50
superflex.
The antenna mounting pipe has a #2 ground wire (33.6 mm/2) the
polyphaser has it's own #2 ground wire.
On 11/26/14, 2:14 PM, Chris Albertson wrote:
You CAN (almost) lightening proof your system. The trick is to give
lightening a low impedence path to grind at very opportunity.
Start with the antenna mast and call. Use iron pipe for the mast and feed
the antenna cable down the center of the pipe
On 11/26/14, 2:54 PM, Hal Murray wrote:
albertson.ch...@gmail.com said:
The ground rod needs to be bonded to the rest of the building ground system.
How do I do that effectively if the power goes in the front of the building
and the antenna is on the back?
AWG 6 wire with no breaks or spli
On 11/26/14, 5:23 PM, Chris Albertson wrote:
On Wed, Nov 26, 2014 at 4:03 PM, Jim Lux wrote:
On 11/26/14, 2:14 PM, Chris Albertson wrote:
You CAN (almost) lightening proof your system. The trick is to give
lightening a low impedence path to grind at very opportunity.
Start with the
Time to stock up on those transformers, mixers, amplifiers
"Throughout the month of December, all online orders of any quantity of
any Mini-Circuits catalog model from our web store on minicircuits.com
will receive a 10% *discount!
"
___
time-nuts ma
On 11/27/14, 7:07 AM, Tim Shoppa wrote:
For a hobbyist doing things a few at a time, what advantage is there to
buying RF transformers made by Mini-circuits etc., vs winding them using
commonly available ferrite cores/binocular cores?
Probably depends on the frequency ranges and such. The com
On 11/27/14, 3:10 PM, Gerhard Hoffmann wrote:
Am 27.11.2014 um 23:30 schrieb Bob Camp:
Hi
Finding the RF transformer parts is still a bit of a challenge.
No. These work quite good for me:
CX2074 4:1 CT
CX2147 1:1 CT
<
http://www.digikey.de/product-search/de/rf-if-and-rfid/balun/3539019?
On 11/30/14, 1:49 PM, Hal Murray wrote:
eb4...@cembreros.jazztel.es said:
Do not trust Google Earth data for any precision work. The mentioned six
feet are probably due to the geographical data, not to the precission of
your GPS unit. If you look for image seams you can verify the kind of
er
I'm looking for a real short (3-4 slides or a website, really)
description of why the phase noise of a PLL (microwave) looks the way it
does, explaining (in sort of qualitative terms) how the phase noise
transitions from the VCO (outside the loop bandwidth) to the reference
(inside the loop ban
On 12/4/14, 2:59 PM, Magnus Danielson wrote:
Jim,
On 12/04/2014 08:41 PM, Jim Lux wrote:
I'm looking for a real short (3-4 slides or a website, really)
description of why the phase noise of a PLL (microwave) looks the way it
does, explaining (in sort of qualitative terms) how the phase
On 12/5/14, 4:50 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
On 5 Dec 2014 12:23, "Bob Camp" wrote:
Shipping across the atlantic has become silly expensive over the last
decade. There are a *lot* of organizations that are behind the curve on
figuring out how to do it cheaply.
Bob
I
On 12/6/14, 6:18 AM, Attila Kinali wrote:
On Sat, 06 Dec 2014 14:47:54 +0100
Magnus Danielson wrote:
Also, GPS L2C and L5 signals is already there.
AFAIK there is no satellite with L5 capabilities in space yet.
Also L2C is still marked as unhealthy.
Attila Kinali
On 12/8/14, 6:15 AM, Brian Inglis wrote:
On 2014-12-07 16:28, Tim Shoppa wrote:
Would any time-nuts know of radiolocation-type testing going on, on east
coast of US, maybe around Maine? There is a very strong wideband
signal on
1900-1920kHz, with a 120Hz substructure and a 4Hz rep-rate, likely
m
On 12/10/14, 6:31 AM, Alan Melia wrote:
Hi Dave, as a long time reader (since 1955) and subscriber I remember
the Amateur scientist pages ending in the 1980s. I think the contributer
retired. At around that time I think the many adherents formed the
Society of Amateur Scientists. Though I have no
On 12/10/14, 9:45 PM, Mike Cook wrote:
Le 11 déc. 2014 à 05:47, Brian Lloyd a écrit :
On Wed, Dec 10, 2014 at 10:15 PM, Chris Albertson
wrote:
Those sub 1 u-second numbers are very good. They argue for using
the BBB as an NTP server but I wonder if it really is the best.
I think the numb
On 12/11/14, 6:14 AM, Brian Lloyd wrote:
On Thursday, December 11, 2014, Jim Lux wrote:
Ah, but will the exact same single board computer be available for
replacement in 5 years?
Most likely not. These days I can't imagine a manufacturer making the same
SBC or mobo board for more t
On 12/11/14, 7:04 AM, Paul wrote:
On Thu, Dec 11, 2014 at 9:45 AM, Chris Albertson
wrote:
Your logic would disqualify EVERY computer made today. What will still be
in production in 10 years?
The ones you make yourself. Or if you're a nation-state the ones you have
made to your specificat
On 12/11/14, 7:35 AM, Paul wrote:
On Thu, Dec 11, 2014 at 9:59 AM, Jim Lux wrote:
Linux isn't a whole lot better. If you have a system you cobbled together
in 2004
In the PPS via GPIO this is an issue and you don't have to go back 10
years. There's been a major change b
On 12/11/14, 8:11 AM, Brian Lloyd wrote:
Discussing the lifetime of NTP server hardware is all well and good but
given the thrust of this list, i.e. individual time-nuttery, I don't see it
as being too germane. Few of us have the same problems that Jim Lux has at
JPL.
Actually, I thi
On 12/11/14, 9:54 AM, Brian Lloyd wrote:
On Thu, Dec 11, 2014 at 10:46 AM, Jim Lux wrote:
Actually, I think my point was that the problems I face at JPL are
essentially identical to the problems we face at home. I'm not in the time
and frequency group (and I don't know that the
On 12/12/14, 5:09 AM, Bob Camp wrote:
———
Are we really that far apart - not really. We each are talking about
two sides of the same coin. The real world is a messy place. Analysis
often takes a back seat to the “fun of doing something”. That’s not
to say it should though …
And sometimes, the
On 9/28/14, 7:55 AM, Richard Karlquist wrote:
I find it odd that an instrument that probably cost $50,000 when new did
not have a TCXO as standard, and perhaps an oven as an option.
But I think HP did this sort of thing a lot. Something that would have
cost
very little to add, became an expen
On 12/14/14, 10:41 AM, paul swed wrote:
Well with zero effort the spec sheet. Bob indeed there are common mode
chokes in them. Jeeze a lot in 1 package along with center taps.
Regards
Paul
WB8TSL
I've seen a lot of MiniCircuits BNC 10.7 MHz BPFs used in equipment
racks over the years as a so
On 12/15/14, 5:35 PM, Bob Camp wrote:
Hi
On Dec 15, 2014, at 8:29 PM, Paul wrote:
On Mon, Dec 15, 2014 at 6:39 PM, Angus wrote:
But is it the closest to the 'true' position that you really want, or
the best estimate of where the particular GPS you are testing thinks
it is?
I don't under
On 12/15/14, 5:46 PM, Dave M wrote:
With all the discussion about surveys & position accuracy, I have a question
about my choke ring antenna. There is an arrow marked "N" on the underside
of the rings. How accurately does the alignment need to be to "N"orth?
True north or magnetic north (my thi
On 12/15/14, 6:46 PM, Paul wrote:
On Mon, Dec 15, 2014 at 9:01 PM, Jim Lux wrote:
if you've got observables and they're in RINEX format, you can do offline
processing through JPL's GIPSY thing..
According to the upload form APPS still requires dual frequency. The
underlyi
On 12/15/14, 8:10 PM, Tom Van Baak wrote:
But to prove us wrong, put the antenna on a 17 hour turn-table, collect data
for 6 months, and then see if you see any 17h peaks in the FFT!
Clever idea, but..
Most rotary joints have more phase and amplitude variability than the
antenna.
So you'
On 12/16/14, 5:59 AM, Tom Van Baak wrote:
Clever idea, but..
Most rotary joints have more phase and amplitude variability than
the antenna.
So you're stuck with rotating back and forth with a cable that's
flexing and now you get to measure the phase variability of the
coax.
I was thinking of
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad different. Should be possible to pull off if
people want to do dual frequency witho
On 12/16/14, 4:06 PM, Bob Camp wrote:
Hi
On Dec 16, 2014, at 7:01 PM, Jim Lux wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just
On 12/16/14, 4:29 PM, Magnus Danielson wrote:
Jim, Bob,
On 12/17/2014 01:06 AM, Bob Camp wrote:
Hi
On Dec 16, 2014, at 7:01 PM, Jim Lux wrote:
On 12/16/14, 3:36 PM, Magnus Danielson wrote:
Paul,
That is indeed the question. Considering that the signal is better
supported, I hope the
On 12/17/14, 4:36 AM, Bob Camp wrote:
HI
On Dec 17, 2014, at 1:07 AM, Chuck Harris wrote:
I would venture that the extent of the magic was to note the physical
center of the array, and call that the phase center.
As long as you always orient the antenna in the same direction, any
errors that
On 12/17/14, 5:20 AM, Dan Kemppainen wrote:
Not sure if this is quite the right platform, but for someone wanting to
experiment it may be worth a look...
https://www.kickstarter.com/projects/swiftnav/piksi-the-rtk-gps-receiver
http://www.swiftnav.com/piksi.html
from that page:
3-bit, 16.368 M
On 12/17/14, 6:46 AM, Chuck Forsberg WA7KGX wrote:
Seems to me CFLs and other loads switching on and off would affect the
60 Hz waveform
enough to make microsecond measurements meaningless.
folks measure the frequency to tenths of a Hz (albeit not a single cycle)..
0.1 Hz out of 60 Hz is 27 m
On 1/9/15 7:42 AM, steph.rey wrote:
Hi Bob,
Many thanks for your prompt and detailled answer.
My question on applications wasn't on good ADEV where I perfetcly
understand the need, but actually what could be the applications of
measuring BAD ADEV (>10e-7). That was my point asking what king of
On 1/9/15 4:57 PM, Henry Hallam wrote:
Such slewing solutions are OK for Google. They wouldn't work well for
one of the systems I work with, which uses system time to calculate
the position of a LEO satellite for purpose of pointing a 7.6 meter
X-band dish. Half a second of error corresponds to
On 1/10/15 3:08 PM, Hal Murray wrote:
hol...@hotmail.com said:
Basically the solenoid nudged the pendulum
There was an article in Scientific American many years ago. They used a
magnet mounted on the end of a stick attached to the pendulum arm. The arc
of the magnet swung through a hole in
On 1/10/15 1:25 PM, Hal Murray wrote:
jim...@earthlink.net said:
Which is why we use TAI in the space business and don't fool with this
"Greenwich Mean Time" or "Coordinated Universal Time" which is
discontinuous and potentially non-monotonic.
Does the system clock on your PCs run on TAI or d
On 1/11/15 7:30 AM, Martin A Flynn wrote:
I am looking for a GMT/GET mission time clock that has the following
characteristics:
* Reads T minus prior to launch or deployment, T plus after.
* Second display for GMT.
* Simulating it on a PC display would be OK, would prefer an LED/LCD
On 1/12/15 1:00 PM, Tom Van Baak wrote:
Yes, you can get an Arduino R3 on eBay for <$4 with shipping...
The GPIB connector will cost you more!
Didier KO4BB
A sandwich of two PCB is about the same thickness as the center plug of a GPIB
male connector. So layout 2x12 pads to match the pins and
On 1/13/15 2:41 AM, Attila Kinali wrote:
On Mon, 12 Jan 2015 20:09:45 +
Gregory Maxwell wrote:
One exception here is space qualified oscillators. For those you
go to the JPL and ask them to help you.
Actually, you want to go to Applied Physics Labs (APL).. they're the USO
folks.
At JP
On 1/14/15 1:40 PM, Brooke Clarke wrote:
Hi Martyn:
On each frequency there are a couple or more different codes.
The Civilian Acess (C/A) code on the L1 frequency is all public
information and so is the most commonly used.
But there are classified codes that have a much higher bit rate and
all
On 1/16/15 4:58 AM, Li Ang wrote:
Hi
I have a question about the GPS antenna. Since the GPS signal strength on
the ground is about 20db lower than the thermal noise, does the gain of
antenna matter?
Not a whole lot.. Obviously, you don't want something -10dBi, and there
is a direct effect o
On 1/17/15 6:59 PM, Ivan.Cousins wrote:
time-nuts members:
What are some signal generators for ATE test?
Requirements:
100MHz to >=10GHz (higher would be better)
Settling time less than 1mS
Reasonable phase noise
Cost, less than mortgaging a house.:)
1ms settling time is fairly fast.
Ho
On 1/25/15 1:30 PM, WarrenS via time-nuts wrote:
I second Poul-Henning Kamp's comments concerning D-terms,
(mostly) as done in the TBolt and likely other GPSDOs.
Bear in mind that a PID loop is basically a fairly simple control loop
that is easily susceptible to linear analysis.
They're s
On 1/26/15 5:55 AM, Poul-Henning Kamp wrote:
In message <54c5a270.7090...@earthlink.net>, Jim Lux writes:
And there's decades, if not centuries, of experience with P, PI and PID
controllers in a practical sense.
Not quite a century I belive: Only the advent of
On 2/4/15 3:55 PM, Mark Sims wrote:
I have seen several issues with Windows programs not releasing (or perhaps not
being able to releaase) the serial ports after using them. Once one of these
programs accesses the serial port, no other programs can use it until you
re-boot. I'm fighting wi
On 2/6/15 1:21 AM, Javier Serrano wrote:
Dear all,
We would like to start working on holdover performance for White
Rabbit [1]. This is a new domain for us. Our main use case is a WR
switch losing its reference because someone disconnects a fiber. We
can have redundancy, but it will take some ti
I have a colleague who's using the Systron-Donner MMQ IMU/GPS unit, and
he's wondering if there's a way to get "integer seconds" out of it. It
uses a Jupiter Pico GPS, I believe, and one of the messages provides
Seconds of Week GPS time, as well as UTC seconds and UTC day, month, year.
So he
On 2/6/15 12:42 PM, Hal Murray wrote:
mag...@rubidium.dyndns.org said:
The typical noise generator chips uses a PRNG based on DFFs and XOR
gate(s). A typical weakness is that the chain of DFFs is to short, causing
a relatively high rate of cycling, which hearable as a beating. However, for
som
Hypertrm right now over this issue
trying to read from a freq counter for some ADEV measurements. Once
HYPERTRM runs, no other program can access the serial port.
Good point, I tried TimeLab direclty after fresh reboots, but the
interfaces are still invisible.
"Jim Lux"
One trick with Wi
On 2/8/15 2:11 AM, Attila Kinali wrote:
On Sat, 7 Feb 2015 10:07:44 -0800
Tom McDermott wrote:
While compensating for cable delay is relatively straight forward by
measuring the length and compensating for
the velocity factor, a question is: how much amplifier / filter group delay
is to be exp
The latest rev of the CSAC data sheet (rev H) shows the max
non-operating temperature to be 40C..
and operating from -10 to +35C
that's a substantial difference from the former version of the sheet
which presumably had the temperatures from the summary page:
The Quantum SA.45s Chip Scale Atomic
On 2/18/15 1:49 AM, Attila Kinali wrote:
You could try tinyVNA[1]. I have used it once, it has some quirks
(it's half hobby, half commercial project and that shows) but works
otherwise. I have no idea how accurate it is.
Attila Kinali
[1] http://miniradiosolutions.com
On 2/19/15 1:59 AM, Attila Kinali wrote:
On Thu, 19 Feb 2015 10:51:04 +0100
Attila Kinali wrote:
When i had one on my desk, i opened it up, but apparently i forgot to take
pictures. From what i remember, i think it works either similar to the
VNWA design done by DG8SAQ[1,2] or by N2PK[3]. The
On 2/19/15 9:11 AM, Matt wrote:
Hi,
My university would like to have a <1ms precise source of time to do
some networking experiments (measure one way propagation delays
etc...). So I wandered on the internet to find the best choice with a
budget of ~1000€ (~1100 American dollars).
I've been over
On 2/20/15 6:30 AM, Chris Albertson wrote:
I think the easiest cable to make really long, if one must be long is the
antenna cable. Use 100 meters of the kind of cable they use for cable
TV. It comes double shield and has those compression type F connectors.
The cable can cary both the GPS sig
Alberto posted some pictures of a GPS receiver from Navstar Systems Ltd..
They're still in business, but don't appear to be doing that any more..
However, I did run across this:
"Sarantel is a spin-off of Symmetricom founded in 2000 by Dr. Leisten.
Leisten was spearheading the development of a n
On 2/21/15 9:32 AM, Alberto di Bene wrote:
So I agree that the best use I can make of that Navstar "mushroom" unit
is to pry it open, and try to find the
electrical signals before they are converted to optical... at least now,
thanks to David, I know what the supply
voltage of the beast is..
On 2/23/15 9:35 PM, Brian Inglis wrote:
On 2015-02-22 17:42, Charles Steinmetz wrote:
Brian wrote:
Thought of trying aerogel insulation?
Dust free varieties avoid handling issues.
Be careful not to over-insulate the oven -- it depends on a certain
amount of heat flow to ambient to balance th
On 2/24/15 4:32 PM, Dave M wrote:
Ok, there has been a couple replies suggesting aerogel. I've read a bit
about it, and understand that it's extremely light and effective, but
quite difficult for a hobbyist to make. Also, probably very expensive.
Is there a source for very small quantities of i
In yesterday's Wall Street Journal (or maybe USA Today, I can't remember..)
Nice Nixie displays...
I wonder if it normally displays the same time on all, or if it is a
multi-time zone/elapsed time kind of thing. It looks a lot like clock
display stacks used for displaying Mission Elapsed Time,
On 2/27/15 3:23 AM, Flemming Larsen wrote:
Check the price here:
Patek Philippe Digital Display Clock
| |
| | | | | | | |
| Patek Philippe Digital Display ClockVintage digital display clock by Patek
Philippe of Geneva. Made for Abou Watfa of Damascus, circa 1970. Rare Patek
Phil
Is there a handy "one pager" kind of explanation of noise spectra after
some forms of signal processing..
For instance, if you have a oscillator which has a 1/f characteristic,
and you mix it with itself, what is the spectra of the output of the mixer.
Or if you have a 1/f^3 characteristic (
On 3/1/15 10:23 AM, Joseph Gwinn wrote:
time-nuts Digest, Vol 128, Issue 1, Message: 8
Date: Sat, 28 Feb 2015 17:46:18 -0800
From: Jim Lux
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] simple explanation of noise spectra with mixing,
etc
On 3/25/15 7:27 PM, Robert Watzlavick wrote:
I'm working on a project that I could use some advice on and also might
be of interest to the list. If it's not appropriate for the list, my
apologies.
I want to develop a tracking system for an amateur rocket that can allow
me to track the rocket e
On 3/28/15 10:27 AM, Bob Camp wrote:
Hi
So If the rocket continuously accelerates at 10,000 G’s, you will get a 20 ppm
shift
with typical sensitivity. If you do this for very long, you will also get into
time dilation issues.
(you hit 0.1C in < 2 minutes).
10,000G is more like an artil
On 4/6/15 2:14 AM, Attila Kinali wrote:
Moin,
On Fri, 03 Apr 2015 22:51:34 -0500
Robert Watzlavick wrote:
On 04/03/2015 10:12 PM, Robert Watzlavick wrote:
I have an amateur radio license (mostly CW/HF and some VHF/UHF
experience) and I've written some driver software for an IQ
demodulation bo
On 4/6/15 2:21 AM, Attila Kinali wrote:
On Sat, 04 Apr 2015 08:49:01 +0200
Magnus Danielson wrote:
This is on either side of the amateur 23 cm band. That's also the first
band where you have bandwidth enough to fool around with stuff like this
without breaking the bandplan.
This shouldn't be
On 4/7/15 11:33 AM, Magnus Danielson wrote:
Hi,
O
One might look at the available frequencies and see if there is a
telemetry band available which allows wider bandwidth. For the
application, I don't see that very much transmitted power is needed.
If the OP is a licensed amateur radio person,
An interesting look back: it's a copy of a Tracor ad showing someone
carrying a portable Rb clock down the stairs of a PSA plane. Lots of
history in that photo: no jetway, PSA, people wearing coat and tie on an
airplane. Even the street name for GTC, on Bellanca Av, redolent of
long-gone airpl
On 4/18/15 7:02 AM, Bob Camp wrote:
Hi
Many years ago while standing around (between races) with some pretty good
stopwatches, a group of us decided to see
just how well a set of people could time the same pair of start / stop events.
Our conclusion was that as a
group we could get agreement t
On 4/20/15 12:59 AM, Attila Kinali wrote:
Moin,
On Mon, 20 Apr 2015 00:40:06 -0700
"Tom Van Baak" wrote:
Mechanical, yes. Home brew, no. It is an absolutely stunning clock,
both in beauty and performance.
Given the fact that a CNC milling machine can be bought quite cheaply
today, i would s
On 4/20/15 7:25 PM, Charles Steinmetz wrote:
Unfortunately, you are unlikely to do any better than this with the
antenna location you described. Time to buy a house, with no tall trees
nearby. (You may already have heard that time-nuttiness can be
expensive ;-)
Actually, what you wan
On 5/6/15 12:53 AM, John Marsden wrote:
Ok, I only ask becuse there seemed to be a big thing about LHCP quad helix
antennas - even to the point of seein an article showing how to 'unwrap. a RHCP
Q-H, and rewrap it 'inside-out' to change the polarisation to LHCP.
I'm seriously considering makin
On 5/6/15 3:09 PM, Bob Camp wrote:
GPS helix antennas were a really big deal in about 1982. Once people started to
get experience with GPS and a variety of designs, they became less of a big
deal. I do not know of any modern
precision antennas that use a helix.
Most precision antennas I've
On 5/7/15 7:23 AM, Attila Kinali wrote:
On Sun, 03 May 2015 07:29:30 +
"Poul-Henning Kamp" wrote:
When you post-process raw GPS data you get to include antenna phase
center / gain / az/el corrections for free.
Speaking of which...
I wonder if anybody ever made a rotating GPS antenna to
On 5/8/15 11:37 PM, Poul-Henning Kamp wrote:
In message , Bob Camp writes:
The “put the antenna up and rotate it to see what happens” experiment
has indeed been done. The objective was not correcting the antenna’s
issues, but validating that their model of the antenna’s phase
center wa
On 5/9/15 5:15 AM, Poul-Henning Kamp wrote:
I spent some time capturing some data today.
The measurements is from my $20 loop-antenna in the attic, which is
something like 8 meters up and 10 meters besides the lawn-mower loop:
http://phk.freebsd.dk/time/20150509.html
Clearly, you nee
On 5/10/15 11:40 PM, Poul-Henning Kamp wrote:
In message <45C7C6B09BC548C19241E4E0673E9E9F@system072>, "Bill Hawkins" writes:
Did the pictures have to be in SVG format?
Is this only a problem for those who routinely use SVG?
A problem how ?
I *like* SVG since you can zoom without p
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