On 10/6/13 9:59 PM, Hal Murray wrote:
The recent discussion of solar flares screwing up GPS timing was interesting.
I just watched Todd Humphreys TED talk again. He's focused on location, but
does mention time in terms of stock exchanges.
Todd Humphreys: How to fool a GPS
On 10/7/13 6:03 AM, Tim Shoppa wrote:
Proposing a random fitting with various curves without an underlying
physical (e.g. Eureqa) model seems... odd. That's more voodoo
engineering/science than anything real. It doesn't surprise me that
computer scientists would propose that as an approach to
On 10/7/13 7:46 AM, Collins, Graham wrote:
Indeed, the inexpensive DVB-T dongles are showing up in many places
including as David noted, decoding GPS.
The AMSAT Fun Cube Dongle is a very capable and interesting device.
Interestingly it uses the same Elonics E4000 front end chip that many
of
On 10/7/13 8:01 AM, David J Taylor wrote:
From: Collins, Graham
[]
I wonder if the Fun Cube Dongle will be likewise changed (perhaps it
already has).
Cheers, Graham ve3gtc
=
Yes, Graham, it already has been updated:
On 10/7/13 2:44 PM, Magnus Danielson wrote:
Which reminds me, there is a nifty tool called fityk that I tend to use
just to view graphs, but has a rather nice set of routines to do various
fits to various curves.
gnuplot's not bad, either..
you define a function f(x) and the free parameters,
On 10/7/13 10:44 AM, David J Taylor wrote:
From: Jim Lux
Yes, Graham, it already has been updated:
http://www.funcubedongle.com/?page_id=1073
Adds more filtering and HF coverage, but also has a dead zone between
~240 and 420 MHz.
So much for receiving signals from Transit at 400 MHz
On 10/7/13 8:31 AM, Chris Albertson wrote:
OK so let's say you have a receiver and detect a certain about of power at
the right frequency. How do you determine which of three cases you have
(1) an actual GPS signal from a satellite. (2) a spoofer (who tries hard to
look like #1) or (3) a
On 10/7/13 4:51 PM, David I. Emery wrote:
On Sun, Oct 06, 2013 at 09:59:50PM -0700, Hal Murray wrote:
Suppose I lived near a major highway. Could I build a receiver that would
count jammers driving by? Could I track them (at least somewhat) with a
directional antenna on a rotator?
On 10/7/13 6:49 PM, John C. Westmoreland, P.E. wrote:
Bob,
I think what you have pointed out is interesting - I have even given it
more than a passing thought on how to design what is on the CellBusted site.
I am working on a design of my own on how to detect low-power RF signals
using a
On 10/7/13 9:30 PM, Bill Hawkins wrote:
In general, we expect a jammer to be involved in criminal activity.
What about a wilderness guide whose reputation is built on finding
the best spots to view Nature's wonders. Should he or she be happy
to let people in the guided group save the
On 10/5/13 3:44 AM, Magnus Danielson wrote:
And I want to do it quickly on a slow processor.
... and a simple high-pass filter won't do it for you?
I suppose so..I'll have to fool with that.
A high pass filter would definitely take out the DC and linear terms,
but I'm not so sure about the
On 10/5/13 8:30 AM, Magnus Danielson wrote:
Hi Jim,
On 10/05/2013 04:52 PM, Jim Lux wrote:
On 10/5/13 3:44 AM, Magnus Danielson wrote:
And I want to do it quickly on a slow processor.
... and a simple high-pass filter won't do it for you?
I suppose so..I'll have to fool with that.
A high
On 10/5/13 8:47 AM, Tim Shoppa wrote:
How slow of a processor are you working with? A modern PC using a general
purpose graphing and fitting tool (e.g. gnuplot) will fit tens of thousands
of points in a fraction of a second.
http://people.duke.edu/~hpgavin/gnuplot.html
If you want to do this in
On 10/5/13 9:10 AM, Joseph Gwinn wrote:
Re: time-nuts Digest, Vol 111, Issue 21
On Sat, 05 Oct 2013 11:54:08 -0400, time-nuts-requ...@febo.com wrote:
Message: 6
Date: Sat, 05 Oct 2013 08:53:52 -0700
From: Jim Lux jim...@earthlink.net
To: time-nuts@febo.com
Subject: Re: [time-nuts] exponential
Here's some sample raw data for those interested in what I'm working
with. Thanks a bunch for all the suggestions.
The overall goal is to take this data, remove the DC bias, linear trend,
and exponential transient baseline; then cleverly excise (or exclude
from processing) areas with obvious
I'm trying to find a good way to do a combination exponential/linear fit
(for baseline removal). It's modeling phase for a moving source plus a
thermal transient, so the underlying physics is the linear term (the
phase varies linearly with time, since the velocity is constant) plus
the
On 10/4/13 1:18 PM, Joseph Gwinn wrote:
On Fri, 04 Oct 2013 14:30:40 -0400, time-nuts-requ...@febo.com wrote:
--
Message: 4
Date: Fri, 04 Oct 2013 10:38:07 -0700
From: Jim Lux jim...@earthlink.net
To: Discussion of precise time and frequency measurement
time
On 10/1/13 11:49 AM, Brian Inglis wrote:
It could well if the electrical utility bills are not paid for a few
months!
On 2013-10-01 12:09, paul swed wrote:
Yes but wwvb is on a AA battery it will run out. :-)
On Tue, Oct 1, 2013 at 1:45 PM, Tom Minnis tom_min...@att.net wrote:
WWV is still
On 10/1/13 4:01 PM, Richard Solomon wrote:
I can see it now:
TSA Inspector: Sir, what is that watch ?
Poor Soul: Oh, that's the new Cesium Watch.
TSA Guy: Holy *^*, shut down the airport, call SWAT,
HI HI
73, Dick, W1KSZ
Interestingly, over the past couple weeks, I've had opportunity
On 9/29/13 3:42 AM, mc235960 wrote:
Le 28 sept. 2013 à 14:26, Magnus Danielson a écrit :
I think the radio elescope(s) needed are much smaller. There are apparently 2 pulsar
clocks installed here in europe, one in St Catherine's church Gdansk and the other in the
European Parliament,
On 9/29/13 1:52 PM, Tom Knox wrote:
Actually Dr Kent Irwin at NIST has developed very small and extremely sensitive
detectors using SQUIDs.
Not exactly a project that can be duplicated at home though. There are a number
of articles about his work on line.
depends on who's home... Don't you
On 9/28/13 4:14 AM, Magnus Danielson wrote:
On 09/26/2013 08:25 PM, Tom Knox wrote:
It seems you would need to think of the Pulsar as the clock behind the GPS sat.
You then have an algorithm to add the other need information at the rec end. To
make things easier add to the constellation one
Don't forget the Doppler and relativistic effects of the earth moving
around the solar system barycenter. But that's not much different
than you do for GPS (e.g. knowing satellite orbits, etc.)
Naturally. You also needs to compensate for their decay-rate as you try
to span longer periods.
On 9/28/13 7:32 AM, Hal Murray wrote:
jim...@earthlink.net said:
Scrolling down, it looks like they're getting a whopping 0.5 dB SNR on
the Crab Nebula pulsar.
How much of the noise comes from local sources vs thermal or galactic?
These are amateurs, so they're probably not using
On 9/28/13 3:55 PM, Bob Stewart wrote:
Just to satisfy my curiosity: what's easiest to detect galactic pulse emitter
(regardless of type), and what's the minimum setup to reliably look at it,
whether it's just during night time, or whatever. Just seeking perspective, I
haven't just won the
On 9/24/13 9:24 PM, Stewart Cobb wrote:
www.nanex.net/aqck2/4436.html
Financial markets in Chicago and New York reacted to news from Washington
-- milliseconds faster than the news could have reached them.
Includes at the end some discussion of news organizations that aren't so
good about
On 9/21/13 11:03 PM, Hal Murray wrote:
albertson.ch...@gmail.com said:
What stops working when things get cold?
On Mars, the solar cells are pointed in the right direction. Why doesn't
it
recover when the sun comes back in the Spring?
They run out of power for running the battery
all the bits of sclk
all the time, or just the LSBs all the time, and the MSBs occasionally.
DI is a fairly old design, so the telemetry format probably isn't very
complex (e.g. it's not like they have dynamically allocated data fields,
etc.)
Jim Lux pretty well demolished the idea that time
On 9/22/13 4:48 PM, Mark Sims wrote:
And my favorites: Nickel-Hyrdogen cells and their silvery cousins. You have
to work REALLY hard to kill them.
Yes, forgot the NiMH too.. although they self discharge
---
for rechargeable?
NiCd (in the past)
Lithium Ion (now)
On 9/21/13 2:30 AM, Rob Kimberley wrote:
David,
The satellite has probably got a Rb as its clock (hopefully more than one).
Very, very few deep space probes carry a Rb ( I can't think of any off
hand). Regular old quartz, usually some sort of tcxo. If they are
doing radio science, then it
On 9/20/13 5:12 PM, Bob Camp wrote:
Hi
Low bid wrist watch used as time base?
-
I'd bet there is some form of master time tick in their RTOS that
keeps everything pumping. Loose the time tick (or the time tick
count) and it all goes away…
yes and no.
Most
from JPL
http://www.jpl.nasa.gov/news/news.php?release=2013-275
Mission controllers postulate that there was an anomaly generated by
the spacecraft's software which left the vehicle's computers in a
condition where they are continuously rebooting themselves. If this is
the case, the computers
On 9/21/13 5:41 AM, Bob Camp wrote:
Hi
I'd be a bit surprised if they were running anything as power hungry as an Rb
all the time when a quartz based device would be smaller / lower power / lower
volume. Of course they may have had mission requirements that drive them to a
hydrogen maser ...
On 9/21/13 5:52 AM, Bob Camp wrote:
Hi
So it's a pretty good AT cut crystal without any compensation of heating. Not
quite a cheap wrist watch, but not a BVA in a dewar flask either.
Yep. The AuxOsc is what is used if you don't want to have the downlink
locked to the uplink.
On 9/21/13 6:03 AM, Magnus Danielson wrote:
On 09/21/2013 02:52 PM, Bob Camp wrote:
Hi
So it's a pretty good AT cut crystal without any compensation of heating. Not
quite a cheap wrist watch, but not a BVA in a dewar flask either.
The environmental perturbations should go quite slow most of
On 9/21/13 6:40 PM, Hal Murray wrote:
jim...@earthlink.net said:
If it gets cold enough (without power from solar cells, it won't generate
enough internal heat to keep warm), it will die. That's probably what
happened to Spirit on Mars. It got cold enough during the Martian winter,
and
On 9/15/13 10:24 PM, David J Taylor wrote:
From: Bob Camp
Hi
All of the ones I've opened up or seen dis-assembled have had the
ceramic plate antennas in them. That very much surprised me early on,
since I *assumed* they had something fancy inside based on their shape.
No argument about the
On 9/16/13 6:03 AM, David J Taylor wrote:
I am thinking about exact time measurement - getting your PPS edge
exactly on the nanosecond. People can add in the length of the cable as
an offset, so they must also need to enter any delay through any
filters, mustn't they?
Agreed that for
On 9/16/13 6:43 PM, John C. Westmoreland, P.E. wrote:
Hello Everyone,
While we're on the subject - not to get too far off on a tangent - I have
been doing 'web-research' on this - but can someone recommend a great site
or reference for the specifications of the GPS signaling sent down by a GPS
On 9/16/13 9:13 AM, David J Taylor wrote:
From: Jim Lux
Of course they would factor all this in. That's why the UNAVCO site has
all the phase center locations and delay behavior for the various antennas.
===
Didn't know about:
http://www.ngs.noaa.gov/ANTCAL/
For what
On 9/16/13 6:51 PM, Bob Stewart wrote:
With all the talk about choke rings, and having spent all my pennies elsewhere, I looked
around to see if there were any do-it-yourself versions. I found this one:
http://www.mauve.gr/var/DIY_Choke_Ring_GPS_Antenna.htm;. Is it worth the
effort, other
On 9/15/13 2:27 AM, Anthony Stirk wrote:
Hi John,
I've found as long as the module has lock the level of timing isn't going
to change so you can use anything really (heck we even us ceramic chip
antennas on some boards). For outside use any active automotive patch
should be fine but keep the
On 9/15/13 1:36 PM, Hal Murray wrote:
j...@westmorelandengineering.com said:
Well, I need something that I can put outside, in the weather, with my
verticals, and other antennas. I am a Ham radio enthusiast, and I want
something I can properly mount and can be an all-weather device and can
On 9/15/13 4:33 PM, Bob Camp wrote:
Hi
All of the ones I've opened up or seen dis-assembled have had the
ceramic plate antennas in them. That very much surprised me early on,
since I *assumed* they had something fancy inside based on their
shape.
I don't know that the thermal expansion
On 9/14/13 6:20 AM, Tim Shoppa wrote:
The math I am familiar with, seems to have mostly developed around
master-slave arrangements associated with radar pulses and (as you point
out) TV. In the MIT Rad Lab series there are some single-purpose treatments
but a good summary is Millman Taub, Pulse
On 9/14/13 11:22 AM, Joe Leikhim wrote:
Microwave injection locking of Magnetrons with beam steering phased
array. Lots of math!
On 9/14/13 5:19 PM, Joe Leikhim wrote:
Funny when I go to the links and read about the subject, time seems to
slowww down
By the way, googling microwave weed burner to find this article turned
up another application of microwave heating for a very different kind of
weed.
Oh wow..
On 9/10/13 7:23 AM, J. L. Trantham wrote:
There also appears to be a ton of 'genuine' Agilent 82357B's from China some
selling for under $155 with free shipping (to US and UK).
Quite the 'dump' of technology. I wonder if there is a USB 3.0 version
coming out soon?
more likely that most
On 9/10/13 8:36 AM, Gerhard Hoffmann wrote:
Am 10.09.2013 16:23, schrieb J. L. Trantham:
Quite the 'dump' of technology. I wonder if there is a USB 3.0 version
coming out soon?
What should that be good for? Using a 350MB/s port to transfer 1MB/s
over the GPIB?
But it looks ever so much
On 9/9/13 5:59 AM, J. Forster wrote:
FYI:
http://thunderstorm.vaisala.com/explorer.html
-John
the underlying National Lightning Detection Network distributes the data
with a timing precision of 1 microsecond RMS. I assume their sensors
are GPS synchronized. The location is done by a
On 9/9/13 8:08 AM, Paul wrote:
Although the inexpensive yet high sensitivity units are nice I'm not
sure why someone would choose a positioning MTK (e.g. Adafruit) over a
timing Ublox (or even an old Motorola style timing receiver).
Sometimes, continuing availability is a bigger design
On 9/9/13 8:36 AM, Bob Smither wrote:
On 09/09/2013 07:59 AM, J. Forster wrote:
FYI:
http://thunderstorm.vaisala.com/explorer.html
Here is another one:
http://www.strikestarus.com/
That uses an ad-hoc network of Boltek detectors, which work ok. I had
one in 1999-2000 at work..
On 9/9/13 1:20 PM, Mark Sims wrote:
A cute little lightning detector based upon the AS3935 lightning detector chip:
http://www.embeddedadventures.com/as3935_lightning_sensor_module_mod-1016.html
___
time-nuts
On 9/9/13 2:21 PM, Mark C. Stephens wrote:
Is 200 amperes @ 2v not lethal?
Not particularly.. any more than putting your fingers across a 1.5 or 3V
battery is lethal.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
On 9/9/13 2:38 PM, Mark C. Stephens wrote:
I have seen a 12v car battery and a wire frame bed to torture victims on
television twice now.
Are you telling me that's bunk?! (pardon the pun)
As someone who used to make their living doing just such physical
effects for film and TV..
It's a
On 9/9/13 3:52 PM, Mark Sims wrote:
The AS3935 has an INT output pin that signals a detection. You could monitor
that. The AS3935 is based upon an internal DSP processing the receiver output.
No telling how long between when the strike occurs and when INT is activated.
On 9/9/13 4:08 PM, Jim Lux wrote:
On 9/9/13 3:52 PM, Mark Sims wrote:
The AS3935 has an INT output pin that signals a detection. You could
In an interesting coincidence, Charles Wenzel (yes, that Wenzel) has a
design for a lightning detector:
http://www.techlib.com/electronics
On 9/6/13 8:36 PM, John C. Westmoreland, P.E. wrote:
Fellow Time Nuts:
Is this a site to be trusted?:
http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx
Regards,
John W.
AGI are the folks who make and sell STK (Satellite Took Kit, I believe)
which has a dominant position in the
On 9/6/13 4:00 AM, Bob Camp wrote:
Hi
A truck jammer isn't what you would use to take out a large area,
you would need 100,000 of that sort of jammer. Since the truckers
that use them get fired, there's a limited number of them in use….
Considering they cost $30, and they're not that easy to
On 9/2/13 7:21 PM, John Seamons wrote:
Somewhat off-topic but it might help someone out: I've had a tough time finding, and
using, files on the net containing raw GPS signal samples to be used with the various
software-only (or software-mostly) GPS receivers out there. I finally got a file of
On 9/4/13 7:35 AM, Didier Juges wrote:
Jim,
You should be able to piggyback a second serial port in parallel with the one
used by NTP (just the Rx line and ground) and use any NMEA decoder.
It does not even have to be the same computer.
I have a quick NMEA decoder for Windows I wrote some
On 9/3/13 7:07 AM, Poul-Henning Kamp wrote:
It is very rare to see courts deal with time precisions less
than minutes, but it seems to have happened in this case:
Interesting (and of course, this case has been in the news recently)..
In this case, all the messages were presumably handled by
On 9/2/13 7:50 PM, Bill Hawkins wrote:
Why do we hardly ever talk about synthesizers - those boxes that
turn 10 MHz into other frequencies?
We do.. there's a fair amount of talk about boxes like the PTS
synthesizers. And there's been talk about 866x series synths, and
perhaps the 3325,
On 9/3/13 10:20 AM, Said Jackson wrote:
Hi guys,
Thanks for the heads up, all should be well now. The auto-renew did not work
because we moved and they had an old CC address. Domains that expire stay
locked for 36+ days to the old owner, so no risk there..
This brings up a good point, we
On 9/3/13 11:21 AM, Poul-Henning Kamp wrote:
In message 5225f8af.60...@earthlink.net, Jim Lux writes:
In this case, all the messages were presumably handled by the same
carrier, so the issue of skew in timestamps is negligible;
Anything but.
The text-messages are likely stamped by the SS7
On 9/3/13 2:47 PM, Tom Van Baak wrote:
Nowhere does the opinion mention if the timestamps were taken on
the same clock or if the two clocks were synchronized.
PHK,
Correct. This is an age-old problem, whether its minutes or
nanoseconds. Time-stamps are inherently relative to a local
I'm looking for an easy way to get current lat lon, when you've got a
GPS-18 hooked up for NTP. That is, the GPS receiver is there doing it's
NTP thing, so presumably it knows where it is.
If NTP is decoding the GPRMC message, it has the lat/lon in it, so how
can I get that info out (in a
On 9/3/13 5:35 PM, Jim Lux wrote:
I'm looking for an easy way to get current lat lon, when you've got a
GPS-18 hooked up for NTP. That is, the GPS receiver is there doing it's
NTP thing, so presumably it knows where it is.
If NTP is decoding the GPRMC message, it has the lat/lon in it, so how
On 9/3/13 6:47 PM, brent evers wrote:
Wouldn't turning off ntp drive it nuts?
At the risk of throwing out the bone head answer and assuming this isn't
going on your next space craft, you could just split the GPS serial (my
quick google showed the 18 to be the serial unit vs usb) signal and run
On 9/3/13 7:14 PM, Pete Lancashire wrote:
Ah the 8660's
Image 22 8660A's in two racks, was an fun tax payer, paid project :-)
We where never told what the master clock was.
Have S/N suffix 0009 in the garage.
For you time nuts, a side hobby should be frequency nuts. How to
produce the
On 8/28/13 9:00 AM, Steven Kluck wrote:
It might appear that the
Torr-Kolen Experiment, which had similar results to de Witte, had similar
temperature compensation and control problems. I think it
would be interesting to run for a year with an east-west coax run, and a
separate north-south
On 8/20/13 8:20 AM, Brian Inglis wrote:
On 2013-08-20 02:45, Björn wrote:
b...@lysator.liu.se said:
The PTTI 1PPS is defined in
http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf
It is 20us long and common in some applications. However the voltage
levels
are a bit high...
The section
Design so that when that module is no longer available, you've got pins and
software switches to use something else. Lots of one off projects depend on
something surplus or cheap, and rapidly become non-duplicate-able when the
parts supply ends.
On Aug 5, 2013, at 1:18, M. Simon
Yes.. You put a gain antenna on the space craft, so for the same tx power, you
get the same flux density on the ground. The gps height was chosen for a
variety of reasons. It is out of the debris band, for one. There's also a
tradeoffs on launch costs, etc. GPS world magazine had a great
On 7/26/13 4:41 AM, briana wrote:
Ever since WINxp arrived on the scene hams who send code via computer
to radios via parallel, serial or usb ports (with serial port converters
following) have seen the latency issue in spades. We're talking about
effective baud rates less that 50. 3-4
On 7/26/13 8:46 AM, Brian Alsop wrote:
Hi Jim,
You mean to imply no commercial programs ever use quick fixes?
heavens no.. Plenty of quick fixes..
It's difference between seat-of-the-pants field engineering and a
theoretical pursuit. There are no humanitarian costs associated with
failure
On 7/26/13 12:50 PM, Didier Juges wrote:
There is a difference between managing the latency (as in ensuring that sound
and video are synchronized, but latency itself is acceptable) and minimizing
the latency as in a Morse code keyer where the operator has to manually control
the generation of
On 7/26/13 8:45 PM, J. Forster wrote:
I gather from the article, the GPS position was spoofed and the autopilot,
in bringing it back to where it was supposed to be, actually took it off
course.
There are places where a few hundred feet makes a big difference, viz. the
Costa Concordia.
IMO,
On 7/23/13 11:03 PM, Chris Albertson wrote:
You can prototype a system with off the shelf parts get a few
computers, old notebook computers, Raspburry pI' or repurposed
routers, what ever you have. Connect a Trimble Thunderbolt GPS to
each one. Each one runs NTP. Connect them all to a
On 7/23/13 4:51 AM, Scott McGrath wrote:
Thanks Jim
Was not aware that 10 Ghz signals could penetrate so deeply. I work for a
enterprise wifi company on the RF side and one of our key challenges is signal
attenuation/distortion by building materials
Any pointers to papers on this?
there's
On 7/22/13 6:30 AM, Tom Van Baak wrote:
For what it's worth, the application is a radar that detects
buried victims in disaster rubble, so the data we are collecting is
basically heartbeats and breathing. the when was the data taken
is a where were we when the data was collected need. The sync
Starting a new thread...
Brian wrote:
Have you considered WWVB? Works fine within structures.
Even though the carrier today is phase modulated one can probably glean
1 ms accuracy from it or the data transmitted.
-- disasters occur world wide, any time day or night, so depending on
WWVB
On 7/23/13 9:15 AM, Chris Albertson wrote:
I don't think those requirements are hard. You can build a system
that works in three cases
1) GPS is available full time
2) GPS is available intermittently.
3) there is not GPS system, world war III has destroyed it.
or you're in an urban canyon
or
On 7/21/13 6:42 PM, Chris Albertson wrote:
I think the way to keep the sensors in sync is to use the same method
they use to keep cell towers in sync. Basically each tower has a GPS
receiver and also a good local oscillator. The GPS disciplines the
oscillator and the timing is taken from that
On 7/22/13 5:48 AM, Scott McGrath wrote:
You might want to look at what these guys have done for 40 years or so.
Www.geophysical.com
ground penetrating radar doesn't work very well in the typical disaster
rubble enviroment which has uneven surfaces and a lot of random
scattering in the
On 7/22/13 10:39 AM, Scott McGrath wrote:
Moles are a bit small it would probably work better for woodchucks. who are in
the process of undermining all lawns in neighborhood now.
In a more serious vein most ground penetrating radar is low frequency and I was
not aware that THz waves could
I don't have a GPS-18 in front of me, and I'm modifying some software
remotely, and I ran across an issue that someone on this list probably
knows off the top of their head.
Does the GPS-18 put out 1pps pulses even if it hasn't got a fix yet?
That is, when you apply power, does it just start
On 7/21/13 7:15 AM, David McGaw wrote:
The GPS-18 does NOT output 1PPS until it acquires lock. Then the 1PPS
stays on even if lock is lost, running from the internal crystal. I
have not checked, but once it reacquires lock I presume it jumps to the
correct second. All outputs including 1PPS
On 7/21/13 6:59 AM, David J Taylor wrote:
My own notes on the GPS-18 LVC are here:
http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm
You may be able to gather something about the electrical characteristics
from that note - the device will happily feed to PC RS-232 ports
connected in parallel
On 7/21/13 9:28 AM, David J Taylor wrote:
From: Jim Lux
[]
Oh, I didn't actually think it would be 10% off.. more like a few ppm,
depending on temperature. I was wondering more what would happen if you
were indoors for a couple days, then went back out, what the box does.
realistically, I don't
On 7/21/13 1:35 PM, Tom Van Baak wrote:
when I'm in a GPS denied environment, it's not just because we're
indoors, it's because we're somewhere that GPS isn't available, so
what I'm really doing is providing a sort of flywheel to keep my
little modules synced with each other. I don't need super
On 7/11/13 12:45 AM, Stefan Heinzmann wrote:
Jim Lux wrote:
On 7/10/13 12:29 PM, Didier Juges wrote:
Jim said:
Now you're confusing me. As far as I am aware, there was the 8663A which
appeared in the early eighties. And much later came the E8663B, and
subsequently the E8663D. I've never
On 7/11/13 3:36 AM, Bob Camp wrote:
Hi
The pseudo random spreading / looks like noise / buried signal thing is the
most common way people piggyback low level signals on a bent pipe.
Assuming that the bent pipe isn't running saturated, which I'm not sure
is a valid assumption. Running TWTAs
On 7/10/13 2:15 PM, Max Robinson wrote:
I think that luminous dial watches still contain a little tritium to
keep them glowing for many hours after the atoms that were excited by
visible photons have all decayed. Without the tritium the glow would
completely go dark after most of the atoms have
On 7/10/13 12:29 PM, Didier Juges wrote:
Jim said:
It's like a HP 8663B (not the modern Agilent E8663).. very low noise,
The Agilent E8663 has similar SSB phase noise spec as the older HP 8662A
(-144dBc/Hz @ 10 kHz with option UNY, versus -143 for the 8662). You seem
to imply they are
On 7/9/13 7:01 AM, Burt I. Weiner wrote:
John,
Unfortunately, there's a lot of money in fear. Being in broadcast
engineering I learned as long time ago to never use the words,
radiation or radiate a signal when referring to a station's signal.
Instead, I refer to it as, Launch or Launched a
On 7/6/13 8:10 AM, jmfranke wrote:
http://www.navipedia.net/index.php/WAAS_Signal_Structure
Doppler Shift: The Doppler shift, as perceived by a stationary user, on
the signal broadcast by WAAS GEOs is less than 40 meters per second
(?210 Hz at L1) in the worst case (at the end of life of the
On 7/6/13 7:50 AM, Joseph Gwinn wrote:
Re: time-nuts Digest, Vol 108, Issue 29
On Fri, 05 Jul 2013 19:55:42 -0400, time-nuts-requ...@febo.com wrote:
OK. Given that the birds WAAS uses were built for communications
purposes, not timing purposes, I'g guess that their frequency reference
is a
On 7/6/13 9:29 AM, Joseph Gwinn wrote:
Code/Carrier Frequency Coherence: The lack of coherence between the
broadcast carrier phase and the code phase shall be limited. The short
term (10sec) fractional frequency difference between the code phase
rate and the carrier frequency shall be less than
On 7/6/13 2:39 PM, Mark C. Stephens wrote:
How Does that Work Robert?
I mean why out of phase?
Then the voltage on the secondary of the buck transformer is subtracted
from the line voltage.
This is a very common thing commercially where you have what's called a
buck/boost transformer to
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