-Original Message-
>From: Magnus Danielson
>Sent: Nov 27, 2017 2:45 PM
>To: time-nuts@febo.com
>Cc: mag...@rubidium.se
>Subject: Re: [time-nuts] Allan variance by sine-wave fitting
>
>Hi,
>
>There is nothing wrong about attempting new approaches, or even
On 12/21/15 3:19 AM, Tim Shoppa wrote:
As an adjunct to the thread about timestamped samples of LORAN
transmissions...
Are there any standard consumer-type audio file formats, that support
absolute time time/datestamps? Would not have to be done continuously, but
something like a time and date
On 12/20/15 12:17 PM, Bill Byrom wrote:
Yes, you can do that. My employer (Tektronix) makes RF Signal Analyzers
which sample at a high rate then use a DDC (Digital DownConverter based
on decimation and digital filtering) to produce a much smaller output
I/Q file at a smaller bandwidth and lower
Here's an interesting problem.
You have a fast sampler that is collecting samples off-the-air (e.g. the
end of LORAN) with a fairly wide bandwidth: say 10 Megasamples per second.
Those samples get post processed in a digital downconverter (not
necessarily in real time) to a narrower band
On 12/14/15 9:12 PM, ed breya wrote:
This may be totally ridiculous, but maybe there's another way to get a
balance wheel signal. The X-band Doppler type microwave motion detectors
can pick up various object signals in free air from quite a distance, so
maybe up close there would be enough
(ADEV of 4E-16 at tau of 1000 seconds is a typical state of the art requirement)
…. and has been since the 1970’s when I first started talking with JPL people
about this :)….
They've gotten a lot smaller and probably draw less power since then.
There's also the testing problem: proving
On 12/8/15 3:31 PM, Bob Camp wrote:
Hi
Let’s see:
EFC uses reference out of the OCXO.
EFC comes on the OCXO at no added cost.
16 bit DAC costs ~$2 to $5
Total cost for EFC setup $2 to $5. Net result is a system with
spurs that are how ever far down you wish them to be. (It’s all
about
On 12/9/15 4:37 AM, Bob Camp wrote:
Hi
On Dec 8, 2015, at 11:20 PM, Jim Lux <jim...@earthlink.net> wrote:
On 12/8/15 3:31 PM, Bob Camp wrote:
Hi
Let’s see:
EFC uses reference out of the OCXO.
EFC comes on the OCXO at no added cost.
16 bit DAC costs ~$2 to $5
Total cost for EFC se
On 12/8/15 8:32 AM, Attila Kinali wrote:
Moin,
I've been digging through some stuff and stumbled (again) over Rick's
paper on high resolution, low noise DDS generation[1] and got confused.
The scheme is very simple and looks like to be quite easy and reliably
to implement. If I understood it
On 12/5/15 12:28 PM, Bert Kehren via time-nuts wrote:
At my new home the GPS antenna location has turned in to a challenge. May
have to splice RG 6U. Has any one done measurements on couplings and the
loss associated with them. Right now I am considering a female, female
coupling. Is there a
On 12/1/15 6:41 PM, Bob Camp wrote:
Hi
So back to the question …. does a 70 (ish) MHz fancy filter really buy you
anything ahead of the main box? If you will be multiply band limited ahead
of the mixer (antenna and saw), the contribution of the 70 MHz filter will
likely be minimal. Note that
On 11/29/15 12:13 PM, Mark Sims wrote:
Another thing to consider is the gravity anomaly caused by that hunk of granite
beneath your clock (or above it in a mine). Hmmm, what is the clock shift at
the top of Mt Everest that is due to the mountain and not the altitude?
On 11/21/15 2:43 AM, Attila Kinali wrote:
On Fri, 20 Nov 2015 15:47:27 -0800 Jim Lux <jim...@earthlink.net>
wrote:
While this is trivial with a GPS receiver, we were thinking about a
very minimalist implementation, with a smart phone as the control
interface.
So, some elect
A couple of us were kicking around the idea of a low cost JT65-like HF
modem implementation, which requires that the station be synchronized to
1 second.
While this is trivial with a GPS receiver, we were thinking about a very
minimalist implementation, with a smart phone as the control
On 11/11/15 3:26 PM, Rob Sherwood. wrote:
The EE department at the University of Colorado has an enlightened professor.
http://ecee.colorado.edu/faculty/popovic.html
Zoya required her students to not only get a ham license, but to build a Norcal
40A.
On 10/31/15 7:32 PM, Bob Camp wrote:
Hi
So … how good is the “calibrate and go” (not the tone on second channel)
approach likely to be?
If it’s a bare crystal or normal XO (not a TCXO) that is supplying the clock,
the crystal will follow some
fairly well known curves. Which one of the curves
On 10/31/15 3:50 AM, Chris Wilson wrote:
31/10/2015 10:46
I have a Racal counter locked to 1 MHz on its rear panel external
input socket from my Trimble Thunderbolt GPS. I derive the 1 Mhz
from a David Partridge divider board. If I also feed the counter
with the 10 Mhz
On 10/28/15 7:48 PM, Jim Lux wrote:
On 10/28/15 7:23 AM, Peter Reilley wrote:
I have been pondering pendulum clocks. I was wondering what the ADEV
of a
pendulum would show. I assume that you could see the errors in the
gear train.
You should see the period of each gear. You should see
On 10/28/15 4:29 PM, Adrian wrote:
That's chapter 6 of his book.
http://rubiola.org/indexx-oscillator-noise.html
Just scroll down for the phase noise plots.
The left hand column of plots contains the essentials.
Adrian
what would be nice is some similar simple analysis for lower performing
On 10/28/15 7:23 AM, Peter Reilley wrote:
I have been pondering pendulum clocks. I was wondering what the ADEV of a
pendulum would show. I assume that you could see the errors in the
gear train.
You should see the period of each gear. You should see the spring wind
down
and being rewound.
On 10/26/15 7:06 PM, Brooke Clarke wrote:
Hi:
I understand 10.230 MHz since when multiplied it gives 1176.45,1227.60,
1381.05 & 1575.42 MHz, all GPS carrier frequencies.
http://www.prc68.com/I/DAGR.shtml#GPSs
But I've got a number of GPS receivers that have Rakon unit oscillators
with a
On 10/25/15 9:37 AM, jim s wrote:
Somewhat time related. The Navy realizes that GPS might not always
work. I don't imagine that aircraft in the US Air Force will be able to
do this very reliably, and the article doesn't mention that service. I'm
guessing that a lot of strategic Air Force
On 10/19/15 7:10 AM, Stéphane Rey wrote:
Hello,
I'm looking for a 10 MHz output GPSDO with external antenna which would
be rackable. Symmetricon doesn't seem to propose some neither Keysight.
MicroSemi now has the product line.. They've got tons of rack mounted
GPS disciplined stuff.
We have
On 10/17/15 6:17 AM, Alex Pummer wrote:
actually, that is a ketch 22, if the loop bandwidth is to low, you will
have low noise , but it may will not lock at all, an other way to try to
filter out the noise, also you may make the loop filter digital, but
leave the the PLL analog, that could have
On 10/16/15 7:45 AM, Martyn Smith wrote:
Hello,
I want to design a digital phase lock loop.
I intend to lock a 10 MHz ultra low noise oscillator that we make to an
external frequency standard.
I need a digital PLL as I’m trying to get a loop bandwidth < 0.1 Hz.
are you locking the
On 10/7/15 1:16 AM, Tom Van Baak wrote:
Stu,
Thanks for the heads up. If you can leak anything from the upcoming paper
please let us know.
Since you're an Iridium expert, would you be able to answer the question? The
OP (John Todd) was asking about reception deep indoors, where GPS signals
On 10/6/15 5:46 AM, Can Altineller wrote:
Hello Jim,
Yes i need a VCXO or even a VCTCXO. However when I search them on ebay,
unfortunately, since they included every term for XO, I am lost in the
noise.
Any recomendations for buying VCXO's that are surplus, and not ebay?
do you want a
On 10/6/15 12:46 PM, Can Altineller wrote:
Hello,
I was hoping for a cheap VCXO. I think those ovenized ones are more
expensive.
Where would I get a brand new VCXO, that has < 1ppm, and specs that are
true. (as in the declared spec would match the actual performance, these
days when we buy
On 9/24/15 11:02 AM, Hal Murray wrote:
xne...@luna.dyndns.dk said:
External Oscillator (the system clock clock) , or External Timer clock
(limited to system clock/4)
That sounds like they are running the external signal through a synchronizer
and then doing all the logic on the system
Got the Rb hooked up.
1E-8, 1E-9 kind of AVAR (after linear trend removal) for 10 minute run.
next, we'll try running it clocked at 96 MHz
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and a better test setup.
You want to understand the systematics when it looks like that.
Cheers,
Magnus
On 09/23/2015 09:09 PM, Jim Lux wrote:
a bit more than 5 minutes of data.
Now to go get a real 1pps source that's decent.
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On 9/24/15 7:13 AM, cfo wrote:
On Thu, 24 Sep 2015 05:30:35 -0700, Jim Lux wrote:
What would be interesting is if there's a pin on the Arduino/Teensy that
you could feed a high quality oscillator to, and then do counting with
that. The K20 microcontroller has a mindbendingly large number
I've got a teensy3.1 hooked up to a 33120 function generator (not
exactly a super stable device) and generating period data for a 1 Hz
square wave.
The period is in "ticks" of the 48 MHz clock, so my thinking is that if
I hook up a good 1pps, what I'm really measuring is the frequency of the
a bit more than 5 minutes of data.
Now to go get a real 1pps source that's decent.
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On 9/21/15 12:13 PM, Robert LaJeunesse wrote:
The Teensy 3.1 (http://www.pjrc.com/store/teensy31.html ~$20) has a Flex Timer
Module that appears to allow a single counter to be captured into independent
registers from independent inputs. Not sure, but PJRC tends to run the clock
fast (96MHz)
On 9/21/15 12:13 PM, Robert LaJeunesse wrote:
The Teensy 3.1 (http://www.pjrc.com/store/teensy31.html ~$20) has a Flex Timer
Module that appears to allow a single counter to be captured into independent
registers from independent inputs. Not sure, but PJRC tends to run the clock
fast (96MHz)
On 9/21/15 12:13 PM, Robert LaJeunesse wrote:
The Teensy 3.1 (http://www.pjrc.com/store/teensy31.html ~$20) has a Flex Timer
Module that appears to allow a single counter to be captured into independent
registers from independent inputs. Not sure, but PJRC tends to run the clock
fast (96MHz)
On 8/29/15 7:19 PM, Alex Pummer wrote:
Hi Bob,
go to your local city library get membership[ here in California it is
free] , and ask them to get from the university library, it will take
some time than they cal you the your stuff is there, you could have it
for four weeks if you need you
On 8/27/15 4:46 PM, Bob Camp wrote:
Hi
On Aug 27, 2015, at 3:58 AM, Hal Murray hmur...@megapathdsl.net wrote:
kb...@n1k.org said:
Is there anything fundamental about SC that forces the turn over
temperature
to be high?
Simple answer yes. More complicated answer : that depends.
The
Someone was asking about changing cut angles and the effect. You might
find some useful stuff in Mark Haney's thesis Design Technique for
Analog Temperature Compensation of Crystal Oscillators
http://scholar.lib.vt.edu/theses/available/etd-11262001-111453/unrestricted/etd.pdf
Here's a matlab
On 8/26/15 4:46 PM, Alex Pummer wrote:
But if he needs 100dBc at 10Hz that is Wenzel's stronghold
[https://twitter.com/ultralownoise]
look that: http://www.wenzel.com/wp-content/parts/501-04517.pdf
Yep.. got one of those sitting on my desk (or one that's very similar)..
but it's a 2x2 block
For a project at work, I'm looking for a good close in phase noise
oscillator (better than -100dBc@ 10Hz, -120dBc would be nice) at 100 MHz
in a SMT form factor. But it doesn't need good temperature stability.
There's tons of SMT OCXOs out there with reasonably good performance,
but they draw
On 8/26/15 1:28 PM, steve heidmann via time-nuts wrote:
Rakon has always impressed me .
I'll take a look. The online datasheets don't have phase noise data for
close in frequencies (at least the 3 I looked at).. some give a
integrated jitter but it's for 12kHz and out, and I've noticed
On 8/26/15 2:38 PM, Gerhard Hoffmann wrote:
Am 26.08.2015 um 22:04 schrieb Javier Herrero:
I suppose that one of the alternatives that you've explored are the
ABLNO from Abracon http://www.abracon.com/Precisiontiming/ABLNO.pdf
looks just like this one from Crystek:
On 8/26/15 1:04 PM, Javier Herrero wrote:
Hello, Jim,
I suppose that one of the alternatives that you've explored are the
ABLNO from Abracon http://www.abracon.com/Precisiontiming/ABLNO.pdf
They say that they are 3rd overtone, but it seems more an AT-cut than a
SC, and anyway is around 10dB
On 8/19/15 10:12 PM, Hal Murray wrote:
t...@radio.sent.com said:
I think that Menlo Park is somewhat under 300 NM (nautical miles) from China
Lake (depending on exactly where the test was located), and the expected
interference range was about 252 NM. So you might have been at the edge of
the
On 8/18/15 10:30 PM, Bruce Griffiths wrote:
The ratio of the resonant frequency of the evacuated cavity to that
of the air filled cavity increases by the square root of the relative
permittivity of the ambient air or around 300ppm or so. Bruce
I believe that there are systems that measure
On 8/11/15 5:20 AM, David C. Partridge wrote:
I just installed Windows 10 (yes I know how rash), and now my Thunderbolt is
being detected as a Microsoft Serial Ballpoint Mouse (yes, just like before
inder Windows 7). I had set something up on Windows 7 in the boot.ini to
stop this, but for the
On 8/9/15 4:33 PM, Bob Camp wrote:
Hi
If you never have tried to keep an IC in production, there are some basic things
that may not be very obvious:
snip
There's always Rochester Electronics.. leaders in the trailing edge
(no kidding, that's their slogan)..
They buy old fabs, masks, etc,
On 8/9/15 7:57 PM, John Allen wrote:
Hi Jim -
You wrote:
At some point, multiproject wafers (like MOSIS) might become a hobby
product. So far, it's in the several kilobuck minimum purchase, and,
as well, the tools aren't easy to come by. Or, more properly, good
design tools are expensive,
On 8/7/15 1:40 AM, Hal Murray wrote:
kb...@n1k.org said:
Well, at least *some* of the chips out there do not make it to 96 KHz when
sampling at 192 KHz. It’s been a few years since I dug into them. Back then
a chip that had an internal filter that went to 96K was very much the
exception
On 8/5/15 8:27 PM, Donald wrote:
On 8/5/2015 7:55 PM, Bob Camp wrote:
Hi
Analog Devices has some very nice ADC’s that are directly targeted at
doing this general sort of thing. They do not have any “odd” filtering
approach
that creates issues. Some of the early 192 KHz audio parts did not do
On 8/5/15 8:03 PM, Donald wrote:
On 8/5/2015 6:44 PM, Jim Lux wrote:
I'm not sure it would buy you much.. you'd have something running at
240kHz switching the inputs to the detector?
It's MUCH easier to just digitize the 60kHz with a high resolution
converter. And have a nice BPF in front
On 8/5/15 12:41 PM, Donald wrote:
On 8/4/2015 9:36 PM, Hal Murray wrote:
kb...@n1k.org said:
So far there have not been any home brew design radios show up that will
demodulate and lock to the new data format. There is plenty of info
on the
transmit format. The demodulation approach is not
The whole USO is about $1M, the vast majority of which is labor.
Analysis, testing, paperwork, etc
Jim
Original message
From: Bob Camp kb...@n1k.org
Date: 07/18/2015 02:10 (GMT+00:00)
To: tim...@timeok.it, Discussion of precise time and frequency measurement
On 7/16/15 8:17 AM, John Stuart wrote:
Here is an interesting link to the New Horizons Mission to Pluto radio
system design.
Note last section describes an OCXO with ADEV = 1E-13 at 1s, and aging rate
of 1E-11 per day.
That's no ordinary OCXO. That's a USO made at APL. The crystal is in a
On 7/10/15 6:23 AM, Azelio Boriani wrote:
From http://www.gps.gov/systems/gps/space/
Block IIA: 3 operational
Block IIR and IIR(M): 19 operational
Block IIF: 9 operational
so they should be 31 satellites working.
Plus various and sundry WAAS and similar signals?
On 7/7/15 9:59 PM, Brian Inglis wrote:
On 2015-07-04 07:13, Jim Lux wrote:
I've got a project I'm working on to make a sophisticated sundial with
moving mirrors. I've got a batch of Arduinos that move the mirrors to
the appropriate places, given the current sun angle, etc.
I've got
On 7/7/15 6:28 AM, Attila Kinali wrote:
Moin,
As we need a need a proper TIC here to do our research, we are
going to buy one from ebay form a seller in the US and let a friend
who is in the US at the approriate time and can pick it up to bring
it back in the plane.
Now the big question is,
On 7/6/15 3:19 PM, Tom Harris wrote:
Since you want simple just use a CGI script written in your language of
choice. Very easy technology to learn, Python has support libraries out of
the box if you want. You have a webpge with carious simple controls on it
like buttons etc, you click a special
On 7/4/15 10:25 PM, Brian Inglis wrote:
Thanks for the good and interesting refs.
One of the interesting points was that normal variations are multiples
of those caused by earthquakes, and annual variations are up to 1ms and 1m.
Another was that the jet streams produce large short term
On 7/4/15 7:53 PM, Hal Murray wrote:
jim...@earthlink.net said:
Exactly... I've got an array of mirrors on az/el mounts (two servos
stacked) and the reflection from the mirrors on the wall forms the display.
How many pixels in that display? Or what is the unit of quality measurement?
What
On 7/5/15 8:43 AM, Bob Camp wrote:
Hi
On Jul 5, 2015, at 8:46 AM, Jim Lux jim...@earthlink.net wrote:
On 7/4/15 7:53 PM, Hal Murray wrote:
jim...@earthlink.net said:
Exactly... I've got an array of mirrors on az/el mounts (two servos
stacked) and the reflection from the mirrors on the wall
I've got a project I'm working on to make a sophisticated sundial with
moving mirrors. I've got a batch of Arduinos that move the mirrors to
the appropriate places, given the current sun angle, etc.
I've got a beaglebone that runs some python code to calculate sun angle
based on time
The
On 7/3/15 9:45 PM, Brek Martin wrote:
Hi Guys,
I feel like I missed “The Big Thing” in time keeping land. I should have
watched my Ublox LEA-5T.
What is the difference if it is in the reporting mode for GPS or UTC time?
If they skip a second UTC, surely the GPS time isn’t run incorrectly
On 7/4/15 11:45 AM, Bill Dailey wrote:
Pysolar
Sent from mobile
Pysolar: staring directly at the sun since 2007
excellent.. thanks..
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On 7/4/15 12:18 PM, Brian Inglis wrote:
(the Japan earthquake in 2011 sped the earth up by 1.8
microseconds/day. The Sumatra quake on 26 Dec 2004 had a bigger
effect: 6.8 microseconds)
By my calculations, that should mean the earth rotated 3mm farther/day
at the equator after Sumatra.
Anyone
On 7/4/15 1:42 PM, Simon Marsh wrote:
Pretty much every webserver ever written allows you to run a script in
response to a request. Nowadays there are frameworks that integrate
closely with the language of your choice and do all the heavy lifting
for you.
If fact, the problem is really too
I should finally de-lurk
since I can perhaps offer some useful opinion on this. Comments inline.
On Sat, Jul 04, 2015 at 06:13:06AM -0700, Jim Lux wrote:
I've got a project I'm working on to make a sophisticated sundial
with moving mirrors. I've got a batch of Arduinos that move the
mirrors
On 7/4/15 12:31 PM, Bob Camp wrote:
Hi
As silly as it sounds, having a separate board for the user i/o is probably the
best way to go.
You already have an empire of devices that (somehow) chat with each other. The
barrier of
“it’s all on one device” has been broken even before i/o has been
On 7/4/15 2:01 PM, Tom Van Baak wrote:
(the Japan earthquake in 2011 sped the earth up by 1.8
microseconds/day. The Sumatra quake on 26 Dec 2004 had a bigger
effect: 6.8 microseconds)
Hi Jim,
Just in case you didn't know -- these are theoretical results only.
There's a guy at JPL (Richard
On 6/23/15 4:02 PM, Tim Shoppa wrote:
Yes, for ferrites, many (all?) of the Amidon FT-xxx parts are perfectly
standard Fair-Rite cores available from full-line distributors like Mouser,
Newark, etc.
Iron powder cores are not stocked by any of the standard distributors that
I know of, but
https://support.microsoft.com/en-us/kb/909614
basically: ignore the leap second, so your computer is fast relative
to UTC, and next time you resynchronize time it adjusts
Windows, these days, runs NTP
http://blogs.msdn.com/b/mthree/archive/2015/01/08/leap-seconds-010815.aspx
On 6/22/15 12:02 PM, Attila Kinali wrote:
Hi,
I was looking up some stuff and realized (again) that I don't know
anything about how magnetic electronic components (inductors/solenoids,
transfomers, baluns, ferrite beads...) work. Yes, I can calculate
the inductance, I know how to get from the
On 6/23/15 4:25 AM, Tim Shoppa wrote:
Experimental Methods in RF Design has a half-dozen pages specifically on
the choices of powdered iron and ferrite materials, and lots of working
circuits and designs with measurements. Aka EMRFD.
http://www.arrl.org/shop/Experimental-Methods-in-RF-Design
On 6/21/15 11:28 AM, Don Latham wrote:
Just for fun, went to the site. $149 for basic, but by the time I added all
the toolboxes I thought (!) I needed, I was over $750. sigh.
Don
Hence the popularity of the student license (or Octave)
___
On 6/19/15 9:30 PM, Bob Camp wrote:
Hi
One of the most interesting things about the last paper mentioned:
On Jun 19, 2015, at 8:57 PM, Charles Steinmetz csteinm...@yandex.com wrote:
Rick wrote:
However, a better tutorial would be the one written by
HP's Dieter Scherer which was published in
On 6/20/15 3:03 PM, Dave Daniel wrote:
I wish the MathWorks would resume that practice. Back in the late 90s
they would sell one licenses for MatLab and SimuLink for an affordable
price if one singed an agreement that restricted one to personal
(specifically, non-commercial) use. My copy from
On 6/18/15 1:46 PM, Brooke Clarke wrote:
Hi Mark:
Is there any documentation on the HB100?
first hit on google for HB100 microwave sensor (recognizing that what
comes up as *my* first hit will probably be different than *your* first
hit)...
On 6/18/15 3:46 AM, Bob Camp wrote:
Hi
Be careful when you do find the data.
When you go very close in on something like a VCO, you get much higher phase
noise
than we normally worry about. Some of the “assumptions” that underly the
measurements
are no longer true. Small angle of modulation
On 6/18/15 10:05 AM, Mark Sims wrote:
If you want to play with a homodyne doppler radar, search Ebay for hb100 microwave
sensor. It is a cute little 10 GHz doppler module that costs around $6. It can
be operated in continuous or pulsed mode. The output does require a couple of op-amps to
On 6/17/15 1:08 PM, Magnus Danielson wrote:
Jim,
John Miles have been a bit active:
http://www.ke5fx.com/brick/brick.htm
Just to give you a start-sample.
those seemed to be all PLL outputs.. I didn't see the bare VCO data.
And, I'm really interested in the 1 Hz to 100 Hz kind of range.
On 6/17/15 1:08 PM, Richard (Rick) Karlquist wrote:
On 6/17/2015 8:22 AM, Jim Lux wrote:
I'm looking for some representative data for inexpensive microwave VCOs
(in the 2.5-6 GHz range, in general). Not in a locked loop situation,
If the phase noise data you have goes to a low enough
On 6/17/15 6:15 PM, John Miles wrote:
Also see http://www.ke5fx.com/gunnpll.html , a quick and dirty but
successful attempt at locking a Gunnplexer in a relatively low (1
kHz) loop bandwidth. The inband noise is likely too high for good
performance in a radar application, but the basic idea is
I'm looking for some representative data for inexpensive microwave VCOs
(in the 2.5-6 GHz range, in general). Not in a locked loop situation,
but just bare: with a DC voltage on the tuning input. I'm particularly
interested in data closer than 100 Hz.
Most of the data sheets (e.g. from
http://www.slate.com/articles/health_and_science/science/2015/06/next_leap_second_june_30_dangers_to_software_military_gps_banking_air_traffic.2.html
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On 6/2/15 4:07 AM, Bob Camp wrote:
Hi
The one thing I would be a bit careful about is the power levels.
Consider an 8 port hub:
5V 3A from each would be 24A total. That’s pretty unusual. Most hubs
give you one or two high current outputs.
There are very few 8 port hubs and lots of 7 port
On 5/18/15 11:06 AM, Brooke Clarke wrote:
Hi Bob:
In the link in the message from Brian it explains that iGPS is for
military users of the Iridium system.
The key feature is to allow a moving vehicle to lock on the GPS signal
while being jammed. They do that and also get a more accurate fix by
On 5/18/15 7:59 PM, Chris Albertson wrote:
Yes GPS can do better than 50M but we are talking about a single fix
from a cell phone in a moving car not a survey receiver. . The
displayed location is better because the phone applies a filter to the
location data. Some thing like a Kalman filter.
On 5/12/15 4:00 PM, Tucek, Joseph wrote:
I'm looking for information on non-GPS time sources.
For background, I need to provide PTP to a cluster where we don't have line of sight to
the sky, and are unlikely to get roof-rights without a fight. There are CDMA solutions
that would work (e.g.
On 5/11/15 12:52 PM, Adrian Godwin wrote:
Is it driven as an inductive loop? That might put it under different
regulations.
On 11 May 2015 17:47, Chuck Harris cfhar...@erols.com wrote:
Yes, but in the case of the lawnmower fence, and the
invisible dog fence, the transmitter drives the fence
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
On 5/8/15 11:37 PM, Poul-Henning Kamp wrote:
In message fc02a5e8-5396-4474-a307-546e10909...@n1k.org, 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
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
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
On 5/7/15 7:23 AM, Attila Kinali wrote:
On Sun, 03 May 2015 07:29:30 +
Poul-Henning Kamp p...@phk.freebsd.dk 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
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
On 4/20/15 12:59 AM, Attila Kinali wrote:
Moin,
On Mon, 20 Apr 2015 00:40:06 -0700
Tom Van Baak t...@leapsecond.com 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
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
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
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