bownes wrote:
I love those Hammond boxes until I have to pay the bill. The one for my n2pk VNA was about $28.
I find the non-parallel sides really inconvenient on the Hammond boxes.
It means you can't mount the boards to the sides of the box, just to
the bottom or the top.
COMPAC (htt
Tom Van Baak wrote:
Steve,
After you're done chuckling, note that one man's "utterly
insignificant" is another group's passion.
A 6 foot person vs. 98 million miles is 6 / (9.8e7 * 5280),
or 1.16e-11, a unitless number that's well within our range
of expertise and fascination; neither utterly n
li...@lazygranch.com wrote:
Most drug store isopropal contain other chemicals to keep your skin from drying out. You can buy electronics grade isopropal. Cheap enough ($5 for a large bottle) if you have a store that stocks it. Fry's Electronics has it.
Of course grain alcohol will do the job.
Eric Williams wrote:
I knew someone who worked with 100% isopropanol who said there was some
safety issue with using it in that, if it ignited, the flame was virtually
invisible.
same is true of most alcohols. Methanol and Ethanol burn colorless (a
problem for race cars in accidents)
_
On 1/4/11 12:53 PM, Hal Murray wrote:
jim...@earthlink.net said:
Similar in concept to waas or tass, the satellite provides a nav signal and
differential corrections.
One of the goals is to make a nav system that performs well (sub meter) in
urban canyons, which conventional gps does not
I
On 1/4/11 12:53 PM, Hal Murray wrote:
jim...@earthlink.net said:
Similar in concept to waas or tass, the satellite provides a nav signal and
differential corrections.
One of the goals is to make a nav system that performs well (sub meter) in
urban canyons, which conventional gps does not
I
On 1/13/11 4:59 AM, paul swed wrote:
Really interesting thread. About a year ago on this thread the same
discussion occurred.
Several thoughts along these lines and frankly I know little accept for what
I read here and online.
I would agree the CS never runs out. Accept for one minor point. We te
On 1/13/11 3:18 PM, Rick Karlquist wrote:
J. Forster wrote:
I'd imagine building a Cs unit might be a bit easier than an H MASER, but
not by much. Certainly a Rb is easier.
-John
Other than the "glassware", building an Rb is entirely possible
in your garage, at least if you are a certifiable
Also, I already have it in the garage and does not feel overly scared by
it. I also have some Americum in a smoke-detector. There is also uranium
in the ground, causing background radiation.
yes, all true, but this is what causes my wife to worry that she will
come home from work and find a
On 1/13/11 2:24 PM, Magnus Danielson wrote:
On 13/01/11 22:55, Rick Karlquist wrote:
Magnus Danielson wrote:
experimentation and learning. The HP/Symmetricom efforts spans from the
60thies. Many steps of improvement, of which only some is found in
papers and patents. But they have left such tra
On 1/14/11 6:55 AM, Robert Lutwak wrote:
Before this indelible conversation goes too far, note that cesium beam
frequency standards are explicitly included on the U.S. ITAR list under
§121.IV.28 and that, under §120.10.a, this prohibits the dissemination of
"(1) Information, other than software
On 1/14/11 8:12 AM, Jean-Louis Noel wrote:
Hi,
From: "Robert Lutwak"
Before this indelible conversation goes too far, note that cesium beam
frequency standards are explicitly included on the U.S. ITAR list under
§121.IV.28 and that, under §120.10.a, this prohibits the dissemination of
:-)
h
On 1/16/11 12:12 PM, Brooke Clarke wrote:
Hi Pete:
The SiGe receiver IC is not much use by itself since you need to
literally be a rocket scientist in order to process its output data.
The GPS1A, with open source software is interesting, but again you need
to be a rocket scientist to modify the
On 1/16/11 5:19 PM, Magnus Danielson wrote:
On 01/16/2011 09:12 PM, Brooke Clarke wrote:
Hi Pete:
The SiGe receiver IC is not much use by itself since you need to
literally be a rocket scientist in order to process its output data.
The GPS1A, with open source software is interesting, but again
On 1/19/11 2:18 PM, Rex wrote:
On 1/19/2011 11:39 AM, lstosk...@cox.net wrote:
Have an extra $1,500?
http://www.symmetricom.com/products/frequency-references/chip-scale-atomic-clock-csac/SA.45s-CSAC/
N0UU
Did you miss the many earlier messages on this list?
They actually had a PR blurb ab
On 1/20/11 5:59 PM, Chris Albertson wrote:
On Thu, Jan 20, 2011 at 5:25 PM, wrote:
Another time I was driving I-5 near Lemoore Navy airstation and got a different
type of jamming. The whole gps display rotate back and forth. No idea how that
jamming was done.
Not just with GPS but in gener
I guess this sad saga boils down to my question for the
Time-Nutters List: How do you deal with breadboarding
when it comes to parts that are ONLY available in
surface-mount configuration (and are just at the size
limit for hand soldering?
you lay out little adapter boards
On 1/23/11 4:27 PM, Samuel DEMEULEMEESTER wrote:
Hi timenuts,
Here is an update for all of you interested by this project. According to the
emails I got, you are a lot ;-)
What if both inputs are terminated into a load (e.g. 50 ohms) rather
than a short? The input circuit in Fig 18 of t
I'm looking for a reference that gives the power spectrum of the output
of a hard limiter (1 bit thresholder) with band limited noise and a
single sinusoid.
At high SNR, the output of the limiter is basically a square wave at at
the input frequency, but as the SNR decreases, it starts to act l
On 1/23/11 7:34 PM, shali...@gmail.com wrote:
Jim,
You should be able to model it in Spice and do an FFT on the output.
Or in Matlab.. Simulation is easy for this one...
I was looking for a paper that looked at it analytically.. I figure it's
such a straightforward thing that someone back i
On 1/23/11 10:01 PM, Magnus Danielson wrote:
Jim,
On 24/01/11 02:35, jimlux wrote:
I'm looking for a reference that gives the power spectrum of the output
of a hard limiter (1 bit thresholder) with band limited noise and a
single sinusoid.
At high SNR, the output of the limiter is basica
On 1/24/11 11:44 AM, Magnus Danielson wrote:
On 24/01/11 07:39, Bruce Griffiths wrote:
jimlux wrote:
On 1/23/11 10:01 PM, Magnus Danielson wrote:
Jim,
On 24/01/11 02:35, jimlux wrote:
I'm looking for a reference that gives the power spectrum of the
output
of a hard limiter (
On 1/24/11 1:19 PM, Magnus Danielson wrote:
What are you *really* trying to achieve? 1-bit ADC at the end of a noisy
channel?
I have a GPS receiver front end (sampler) that normally one tests by
running GPS signals through it, acquiring and tracking the signals and
deriving SNR estimates,
On 1/24/11 1:41 PM, Bob Camp wrote:
Hi
Most communications systems also have constraints based on signals in
adjacent channels. That pretty much forces a solution of "lots of filter
before lots of gain". Distributing both gain and filtering across multiple
stages gets you into a variety of issue
On 1/25/11 10:47 AM, Magnus Danielson wrote:
Jim,
On 25/01/11 14:53, jimlux wrote:
On 1/24/11 1:19 PM, Magnus Danielson wrote:
What are you *really* trying to achieve? 1-bit ADC at the end of a noisy
channel?
I have a GPS receiver front end (sampler) that normally one tests by
running
On 1/27/11 5:17 AM, Luis Cupido wrote:
Hi,
Is there a DDS spur prediction software around ?
Not generically..
There is a dissertation out there with some matlab code. I'll see if I
can find a link
Most of the time what I do is write a little program in matlab/octave,
run a bunch of sampl
On 1/27/11 5:17 AM, Luis Cupido wrote:
Hi,
Is there a DDS spur prediction software around ?
I mean for an arbitrary DDS design, like I would
implement with logic or fpga etc.
A code where I can enter nr of bits adc bits etc.
(not a thing for a particular analog-devices chip or
other dds chip)
On 1/27/11 5:17 AM, Luis Cupido wrote:
Hi,
Is there a DDS spur prediction software around ?
I mean for an arbitrary DDS design, like I would
implement with logic or fpga etc.
A code where I can enter nr of bits adc bits etc.
here's a good start.. Martin Pechanec's work...
http://geociti.es
On 1/27/11 11:19 AM, ehydra wrote:
I found chapter Appendix 7A "Analysis of interference in a hard limiter"
There is a half page with a couple of formulas. Not much, not
practically oriented. Only idealized hard-limiters.
I'm interested in SOFT-limiters!
Soft limiters are even more complex to
On 1/27/11 3:20 PM, Hal Murray wrote:
jim...@earthlink.net said:
Most metals have a specific heat around .34, where water is 1.0. ( so .34
BTU to raise a pound od aluminum by 1 deg F)
Where did you get that?
probably misremembering.. Standing in an airport terminal trying to
figure out whe
On 1/28/11 3:59 AM, Luis Cupido wrote:
Jim, Bob, Henry, Brian,
Thanks to all.
Very good.
yeap, I do work on matlab so I think there is plenty now
to keep me busy ;-)
tks.
Luis Cupido
ct1dmk.
p.s.(what's cooking)
I need a relatively narrow tunning range
but absolutely free of close in spurs,
On 2/2/11 6:31 AM, Mark Spencer wrote:
Hopefully timing receivers using elevated gps antennas with band pass filtering
(ie. the 58532A or equivalent..) and a good sky view and strong signal levels
will be more resistant to out of band interference than a typical consumer grade
portable GPS with a
On 2/2/11 7:14 AM, Mike S wrote:
At 09:45 AM 2/2/2011, jimlux wrote...
what was interesting is that the jamming/fail to get fix was at a
closer distance for the consumer receiver than for the FAA approved
receiver for aircraft. Maybe it's better signal processing in the
(presumably
On 2/4/11 1:18 PM, Magnus Danielson wrote:
On 02/02/11 19:47, Hal Murray wrote:
Bottom line - there's a lot to look into, and they are unlikely to
help you
out.
There are a lot of FPGAs used in DSP applications where the clock to the
front end ADC is critical. So I'd expect there would be so
On 2/5/11 3:04 AM, Magnus Danielson wrote:
On 05/02/11 04:33, jimlux wrote:
On 2/4/11 1:18 PM, Magnus Danielson wrote:
On 02/02/11 19:47, Hal Murray wrote:
Bottom line - there's a lot to look into, and they are unlikely to
help you
out.
There are a lot of FPGAs used in DSP applica
On 2/5/11 3:54 AM, Magnus Danielson wrote:
On 05/02/11 12:13, jimlux wrote:
And where in-situ changes in the signal processing are needed (e.g. in a
software defined radio), the reprogrammable FPGA is a good fit. But
there is a tradeoff.. you might want to give the downstream
users/programmers
Here's an interesting problem..
I've got a system at work with an internal clock oscillator that I want
to get some statistics on, but there's no direct visibility for the
oscillator, nor do I have a convenient test point that I can probe.
I can divide it down by an arbitrary number to genera
On 2/5/11 7:30 AM, Poul-Henning Kamp wrote:
In message<4d4d6bf6.8070...@earthlink.net>, jimlux writes:
First, this isn't that different from the analysis used in the NTP
protocol, so you should read that with an open mind.
That is what got me started thinking it was doable at all
On 2/5/11 8:05 AM, Charles P. Steinmetz wrote:
John K1AE wrote:
Once you install their small unobtrusive application
Yeah, right. If there's anything worse than facebook's privacy
practices, it's a service provider that requires you to download a
"small unobtrusive application"
The sm
On 2/5/11 8:11 AM, Magnus Danielson wrote:
On 05/02/11 16:25, jimlux wrote:
Here's an interesting problem..
I've got a system at work with an internal clock oscillator that I want
to get some statistics on, but there's no direct visibility for the
oscillator, nor do I have a
On 2/5/11 10:14 PM, Hal Murray wrote:
I've got a system at work with an internal clock oscillator that I want to
get some statistics on, but there's no direct visibility for the
oscillator, nor do I have a convenient test point that I can probe.
...
Fun problem. Thanks for tossing it out.
On 2/5/11 10:20 PM, Tijd Dingen wrote:
You don't feed the ADC from the FPGA if you can avoid it.
especially if your ADC clock is a different frequency from the processor
clock that's being used for most of the other logic on the FPGA. I'd
give a ballpark estimate of 20-30 dB isolation between
On 2/6/11 12:37 AM, cook michael wrote:
I had a quick look at the IEEE-1355 HIC bus on which spacewire is based
and it seems that although the clock is not on the wire, it can be
reconstructed as an XOR of the strobe and data. So a passthrough
connector sampling those lines (differential) with RS
On 2/8/11 6:32 AM, Mark Kahrs wrote:
The Goertzel algorithm is only useful when you want a few frequences
(i.e., it evaluates specific frequencies on the unit circle). For
general all purpose slicing and dicing, the FFT is what you want. See
the ancient book by Rabiner for the details.
The C
On 2/9/11 3:17 AM, Tijd Dingen wrote:
(if you want some ancient FORTRAN IV code for this, I've probably got a listing
in a box out in the garage from the 70s)
Does this box also happen to contain verilog code for it?
I don't think Verilog was even a gleam in the inventors' eyes back in
t
On 2/9/11 2:08 PM, Tijd Dingen wrote:
The autocorrelation processing is O(N^2) while the DFT can be done in
O(N log N) when using FFT. As usual these can be implemented in reversed
order such that first the FFT is done to the phase jitter and auto-correlation
can be found using O(N) post-proce
On 2/9/11 5:41 PM, Chris Albertson wrote:
On Wed, Feb 9, 2011 at 8:23 PM, Charles P. Steinmetz
wrote:
From a news release issued by the FCC today:
"The FCC Enforcement Bureau today announced new efforts to clamp down on the
marketing, sale, and use of illegal cellphone and GPS jamming device
On 2/13/11 8:15 PM, gary wrote:
Two authors come to mind regarding crystal oscillators: Eric Vittoz and
Marvin Ferking. Eric Vittoz is the more modern of the two. His writings
tend towards long term stability of crystal oscillators. Basically, most
designs put too much energy into the crystal, wh
On 2/14/11 7:47 PM, Shawn Tayler wrote:
Very interesting Bob Thanks.
It brings to mind an annoying issue I run into from time to time.
VCXO 12.8 Mhz used as a reference in communications gear. Most of the gear is
roughly 10 years old and of similar make, both mobile and portable styles.
The
On 2/15/11 10:21 PM, Heathkid wrote:
BLING?
For time-nut bling... I suggest updating the cesium wrist watch on tvb's
site. Come on folks.. who will be the first to sell a *real* atomic
wristwatch (not one of those feeble things that receives a signal from
WWVB).
Doesn't have to be Cs or
On 2/15/11 11:10 PM, cook michael wrote:
Le 16/02/2011 07:21, Heathkid a écrit :
BLING?
Really? Seriously? A "watch" is considered "bling" now? Can you build
a mechanical watch in your workshop that is as accurate as those
manufactured 100 years ago? That's technology! Otherwise, a precision
On 2/16/11 1:13 PM, Joe Leikhim wrote:
For clarification;
I am investigating an experiment using GPS to create a FHSS or DSSS
project similar to those of AMRAD and described in the ARRL Spread
Spectrum Sourcebook. In those experiments, a specific shift register
sequence was used (see below), the
On 2/16/11 1:13 PM, Joe Leikhim wrote:
For clarification;
I am investigating an experiment using GPS to create a FHSS or DSSS
project similar to those of AMRAD and described in the ARRL Spread
Spectrum Sourcebook. In those experiments, a specific shift register
sequence was used (see below), the
On 2/16/11 4:58 PM, Joe Leikhim wrote:
Thanks Hal;
Transceivers A and B (C etc) would extract clock and 1 PPS from their
own GPS. The idea is to use 1 PPS (or derivative) to reset periodically.
Yes the propagation delay A-B would limit the hopping/spreading rate
unless some mechanism to correct
On 2/16/11 5:04 PM, Joe Leikhim wrote:
Thanks Bob;
Does this mean that the 10 MHz clock needs to be somehow divided to an
integer evenly divisible by 127 seconds?
Also 8192 seems to be unfeasible as it would take 2.2 hours to
initialize sync.
No.. your 1pps/sync loads the register with all
On 2/17/11 3:42 AM, shali...@gmail.com wrote:
Or you try all the possible solutions all at once in parallel in a big FPGA and
you have instant synch (at least in the time it takes to recognize you have it)
May be impractical for very long, complex sequences...
If the sequence is long, then w
On 2/17/11 7:22 AM, Joe Leikhim wrote:
I am trying to stay within the FCC Part 97 rules. The spreading or
hopping will be of a narrowband (25 KHz BW) FM signal. I haven't decided
on either the FHSS or DSSS approach. I had thought of a FH approach that
exploited time of day to address a frequency
On 2/17/11 9:30 AM, Bob Camp wrote:
Hi
System design is always about compromise.
If you hop slowly, you "stomp" on each channel pretty hard. You are likely
to get noticed when you do. The idea is to stomp so rarely and for so short
a time that you aren't noticed.
If you hop fast, you need to a
On 2/17/11 2:46 PM, Hal Murray wrote:
li...@rtty.us said:
The key item here is that the system is going to work via amateur radio here
in the US. The FCC only lets you use three very specific PN sequences. The
three are called out explicitly in the rules. The requirement that they not
be reset
On 2/20/11 8:55 PM, John Seamons wrote:
I've been looking at this a bit recently.
Pictures here: http://jks.com
I *am* impressed...
And what a coincidence that phk's name can be adequately done on a 7
segment display (or did he have particularly clever parents?... I can
only do one of my chi
On 2/21/11 10:12 PM, Michael Lombardi wrote:
I'm trying to determine the first product that could automatically
decode and display a digital time code. Digital time codes were
added to WWV in 1960 and WWVB in 1965. This was before they were
added to any satellite signals, or before they were
On 2/22/11 9:47 AM, michaelalomba...@comcast.net wrote:
Thanks very much for the replies so far. I should have been more clear. I am
looking for the first radio controlled clock
that received a digital time code from a radio transmitter. Not a telegraphic
time code (those date back to around
On 2/22/11 12:12 PM, Magnus Danielson wrote:
Hi Jim!
On 02/22/2011 02:34 PM, jimlux wrote:
On 2/21/11 10:12 PM, Michael Lombardi wrote:
I'm trying to determine the first product that could automatically
decode and display a digital time code. Digital time codes were
added to WWV in 196
On 2/23/11 4:48 AM, Bob Camp wrote:
Hi
Hop rates below 1,000 per second are far more common in simple systems than
anything faster than that. At VHF, you are looking at a everybody being within
one hop of each other. That makes the idea of a GPS based code start fairly
reasonable.
Bob
yes
On 2/23/11 5:09 AM, Javier Herrero wrote:
El 23/02/2011 05:53, jimlux escribió:
CCSDS time codes reference NASA 36 bit.. maybe a reference it's in the
back of the CCSDS standard.
First CCSDS.301 issue seems to be January 1987, and references (on the
4th issue, Nov 2010) listed at last
On 2/24/11 5:23 PM, Bob Bownes wrote:
What is the conversion factor for Richter to dBm? :)
Bob
As a guy with degrees in geology and EE. I really should know this...:)
Especially since both are log scales..
The problem is that Richter is log magnitude displacement on a
particular kind of se
On 2/25/11 3:05 AM, ewkeh...@aol.com wrote:
As part of the D/M project the counter uses a 100 MHz VCO with an AD 4001
PLL. To simplify further I would like to consider a very simple VCXO, easily
available components, no tuning, any ideas out there. For once phase noise
is of no concern.
Bert K
On 2/25/11 7:13 AM, scmcgr...@gmail.com wrote:
Speaking as a ham, if this is tried you will have hams complaining and DF'ing
the offending signal.
Speaking as a ham, and as someone who used to build (and attempt to
detect and jam) systems like this for a living..
The odds that a OO would se
On 2/25/11 7:55 AM, Poul-Henning Kamp wrote:
In message, "Wil
liam H. Fite" writes:
Me: You're saying that the Richter is a poor predictor of surface
disruption?
For damage assement you really need a vector-version of richter,
vertical does a lot more damage than horizontal on average.
Y
On 2/25/11 1:28 PM, paul swed wrote:
seems the first document doesn't work.
Any other way to get it?
Just tried it, and it worked for me...
you could probably find it by googling the title or the document number
(NASA SP-80)
it's probably also in NTRS (NASA Technical Report Server) alth
On 2/26/11 4:58 AM, scmcgr...@gmail.com wrote:
Hi Chuck
I'd see you on my waterfall display. A flexradio is a wonderful thing. The
Icom 7x00'es would also see the energy and display it.
Maybe, maybe not.
Depends on what other activity there is in the band and what the noise
properties are
On 2/26/11 5:23 AM, ehydra wrote:
If one looks in the spectrum in a very fine granular structure the data
transferred by SS will be seen on every single spread-code bit!! All
needed is a high-enough S/N and a lot of computing power. On the analog
side the receiver must be very strong signal capa
You know, elements we love, Rb, Cs...
http://www.youtube.com/watch?v=eCk0lYB_8c0
Totally safe for work.. (my daughters turned me on to this video, they
saw it in their 8th grade science class)
___
time-nuts mailing list -- time-nuts@febo.com
To unsu
On 3/2/11 8:21 PM, Mike S wrote:
At 08:43 AM 3/2/2011, jimlux wrote...
You know, elements we love, Rb, Cs...
http://www.youtube.com/watch?v=eCk0lYB_8c0
Totally safe for work.. (my daughters turned me on to this video, they
saw it in their 8th grade science class)
When do we get to hear
On 3/3/11 9:34 AM, Bob Camp wrote:
Hi
There's obviously major fuel behind this thing. I'm willing to pass up GPS
underground. It's GPS out in the open that is my main concern. IF they are
going to use this for "last mile" connect to homes it will indeed be
everywhere and anywhere. IF that's the
On 3/7/11 9:37 PM, Tom Van Baak wrote:
I think it's simple, at least in the nice/common cases. If the antenna
geometry has a point that everything swivels around, consider that to
the the location of the antenna. I think that covers the typical
alt-az mount:
http://en.wikipedia.org/wiki/Altazimut
On 3/7/11 10:27 PM, Chris Albertson wrote:
On Mon, Mar 7, 2011 at 7:34 PM, Bob Camp wrote:
Hi
Since you are after timing off of the sat's, having antennas that move, either physically
or electrically seems like a problem. Any shift in the effective antenna location as you
tracked the satelli
On 3/8/11 4:24 AM, Pieter ten Pierick wrote:
Hi,
GPS phased arrays aren't new, nor is it necessary to physically steer
the antennae within the aray:
http://www.navsys.com/papers/0005004.pdf
But would such a system help with the LNA overload due to a local
transmitter?
I would expect that us
On 3/8/11 9:57 AM, Kevin Watson wrote:
Hi Jim,
As part of my research into keeping time on rockets and spacecraft, I
joined
this list to see what I could learn from the masters. Of course I'm a
knuckle-head for not assuming that you'd be one of the resident masters
. Anyway, as my accuracy needs
On 3/8/11 11:41 AM, Chris Albertson wrote:
On Tue, Mar 8, 2011 at 9:57 AM, Kevin Watson wrote:
Hi Jim,
As part of my research into keeping time on rockets and spacecraft, I joined
this list to see what I could learn from the masters. Of course I'm a
knuckle-head for not assuming that you'd be
On 3/8/11 1:45 PM, Magnus Danielson wrote:
Kevin,
On 03/08/2011 06:57 PM, Kevin Watson wrote:
Hi Jim,
Do you, or anyone else, have a recomendation for the GPSDO? Jackson Labs'
(http://jackson-labs.com/) DROR seems like it might work, but I wonder if
there might be better alternatives.
Firs
On 3/8/11 9:08 PM, Kevin Watson wrote:
Hi All. Thanks for responding. There are quite a few GPS receivers that
will work outside of the usual commercial-grade GPS limitations, but I'm
not too sure I need such a receiver. As my application is to just
accuratly time-tag messages for a data recorder
On 3/8/11 11:05 PM, Magnus Danielson wrote:
On 03/09/2011 06:08 AM, Kevin Watson wrote:
Hi All. Thanks for responding. There are quite a few GPS receivers that
will work outside of the usual commercial-grade GPS limitations, but I'm
not too sure I need such a receiver. As my application is to ju
Lots of people use GPS for timing because it's cheaper or more
convenient in a budgetary sens than alternate approaches. Here at JPL,
it's easier, in general, for me to put a GPS timing receiver and GPSDO
in a lab than it is to try and run cables from the "house sources".
The latter require
On 3/9/11 10:58 AM, Kevin Watson wrote:
Hi Magnus,
As I said in an earlier message, this is an experiment that I want to
run and would rather not touch mission and safety-critical GNC
components, like our navigation GPS receivers. Mass is not an issue.
-Kevin
So this makes it pretty simple..
On 3/9/11 11:40 AM, Jim Kusznir wrote:
Thanks for the info!
I was adjusting the levels with alsamixer, which I suspect is a
digital mixer. I hadn't thought of the potential issues there.
I was using the onboard sound, but I also have a "higher quality"
Soundblaster sound card. Do some of thes
On 3/9/11 5:43 PM, Sanjeev Gupta wrote:
On Wed, Mar 9, 2011 at 22:09, jimlux wrote:
OTOH, if you're building a rocket that's big enough to need something like
this, you can likely get the needed export licenses, or at least, comply
with the export control laws.
Wait, he _is_ exp
It is more a matter about that the involved technology could be ITAR
classified or with other export restrictions. Ask Hughes and Boeing
about the fine for export control violations in Intelsat 708 :)
http://en.wikipedia.org/wiki/Intelsat_708
I think most people who work with rockets with guid
On 3/15/11 1:49 AM, Chris H wrote:
Hello,
Firstly may I just say, my thoughts are with members of this list who
are in Japan.
Just a bit of an odd question...
I hear in the Media that the earth quake sped the rotation of the earth
up..
Can anyone confirm this?
Yes, the media reported it. Yes,
On 3/15/11 6:20 AM, jimlux wrote:
On 3/15/11 1:49 AM, Chris H wrote:
I hear in the Media that the earth quake sped the rotation of the earth
up..
Can anyone confirm this?
No.. the magnitude of the change is parts in 1E11 or thereabouts.
Regular old tidal drag slowing is bigger, and that&#
On 3/15/11 9:36 PM, Hal Murray wrote:
If I were doing this in my backyard on a budget I'd mount a small
telescope nearly straight up so that a bright star would pass through
the field on several nights. I'd measure the light of the star
through a slit and time the peak of the light each night.
On 3/15/11 11:08 PM, Bruce Griffiths wrote:
jimlux wrote:
On 3/15/11 9:36 PM, Hal Murray wrote:
If I were doing this in my backyard on a budget I'd mount a small
telescope nearly straight up so that a bright star would pass through
the field on several nights. I'd measure the li
On 3/16/11 11:31 AM, Chris Albertson wrote:
On Wed, Mar 16, 2011 at 1:14 AM, Hal Murray wrote:
Your pointing accuracy is Y/X, or something close to that.
That describes perfectly when radio can beat optics. The angular
resolution of the system is the aperture size over the wavelength.
So y
On 3/16/11 6:55 PM, Bob Camp wrote:
Hi
Every place I have lived here in the US wants you to put a simple ground block on the antenna lead.
It's not much of an arrestor compared to the "real thing". Since the auction sites will
sell you the right part for less than $20 (at least they used to) t
On 3/17/11 12:30 PM, Chris Albertson wrote:
On Wed, Mar 16, 2011 at 11:00 PM, jimlux wrote:
Synchronizing the several receivers that are spread aroud is not
really even required. Many years ago astronomers would mail magnetic
tapes and the data would be combined days after the observations
A 10-12m diameter dish is probably close to the minimum feasible aperture.
A 4m dish can be made to work in conjunction with a mauch larger dish
(eg 30m).
The original speculation was for measuring the small change in earth
rotation rate, for which some sort of interferometric measurement o
That's an interesting idea, but I think all the orbit data for GPS satellites
is Earth relative rather than star relative. I wonder if the group that
drives the GPS satellites even knows their location relative to the stars.
I'll bet not.
I'll bet they do. Lots of earth orbiting satellites u
On 3/18/11 9:20 PM, li...@lazygranch.com wrote:
http://www.astronomycast.com
Episode 211 was a good primer on celestial navigation. It covers time piece
construction.
Building your own backyard continental drift hardware would be high on the
coolness scale.
good gps measurements processed
On 3/19/11 10:41 PM, Bruce Griffiths wrote:
Bruce Griffiths wrote:
jimlux wrote:
A 10-12m diameter dish is probably close to the minimum feasible
aperture.
A 4m dish can be made to work in conjunction with a mauch larger dish
(eg 30m).
The original speculation was for measuring the small
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