To me it doesn't look like a real jump but rather a result of aggregated
systematics. I think it is related to satellite orbits and how they
provide number of birds or lack of good symmetry, or both.
Both september 28th and 29th have equivalently large jumps as october 9th.
Cheers,
Magnus
On
On Sun, Oct 12, 2014 at 12:28 AM, Chris Albertson
albertson.ch...@gmail.com wrote:
On Sat, Oct 11, 2014 at 1:50 PM, Javier Serrano
javier.serrano.par...@gmail.com wrote:
It's as free-as-in-freedom as we could make it: schematics, layout,
case and code, all using free tools.
That is really
I use that chip in an old project with an 8051 microcontroller. They are
becoming obsolete, I had to switch to the PSD913F if I recall correctly (or
maybe the other way around?)
I have a couple of the programmers too. They work from the printer port, you
are talking about certifiable dinosaurs
Hi All,
I am building a house extension and part of the works involves adding a
new hip roof made of corrugated iron. I was thinking I would pass a
50mm pvc pipe through the roof with a tee and then mount two conical gps
timing antennas on top of it. I am in a low point and don't have
Bruce,
Thanks, I recall the thread from reading the digests. The CERN code is
wonderfully compact but not immediately obvious to a novice to VHDL.
Perhaps one day the light will come on.
Bob
On 10/12/2014 12:27 AM, Bruce Griffiths wrote:
Original thread on DDMTD in 2008:
Hi
With *all* of these “drop to a lower frequency” approaches, the theoretical
resolution is very good compared to the useful resolution. A straight mix to 1
Hz into a 5370 is a great example. The filter / limiter is the thing that sets
the useful resolution rather than the theoretical
Tim
The antennas should not interfere with each other due to rf leakage because
of the way the systems are designed. I will believe you are using 2 rf
feeds.
The more you can clear the trees the better. My very simple solution is a
90' tower.
A bit of humor it does have other uses.
Regards
Paul
First off, why only 50mm and why plastic? The PVC will degrade in the
sunlight over the years. Use galvanized iron pipe. Make the mast as
tall as you can. It can extend sever feet below the roof and attach to
house structure using u-bolts. (Hight limited only by appearance from the
street.)
Interesting 2008 discussion on using a sound-card ADC for a DMTD system!
Did anyone build a DMTD-system and measure the performance using a 24-bit
soundcard?
Does it matter that the ADC in the sound-card is probably clocked by a
crystal clock that is 50ppm off and has bad ADEV?
Anders
On Sun,
Hi Mark - do you recommend one 5370 Extender set or two?
I definitely want one.
Regards, John
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims
Sent: Saturday, October 11, 2014 11:46 PM
To: time-nuts@febo.com; volt-n...@febo.com
Subject:
If you want to add wi-fi to a project, take a look at the ESP8266 wifi
system-on-a chip. It has a wifi transceiver and a 32 bit processor on a single
chip. People have been getting 300 meter range with a PCB antenna. There is
now a GCC compiler for it... lots of work going on here:
Hi
If you are going to get any benefit from multiple antennas, you want to space
them as far apart as possible. You are better off with one antenna and a
splitter than with two close spaced antennas.
The cost of mucking around on the roof is non-trivial. The world is headed to
L1/L2
We certainly allow, maybe even encourage, occasional sales of time frequency
related stuff on the list.
But please send inquiries, orders, and replies directly to the OP, rather than
the entire list.
In this case your emails should go to: Mark Sims hol...@hotmail.com
Thanks,
/tvb
Hi Mark -
I suspect that 90% of the work could be done with a single kit. That will get
one card out of the chassis. But, there are always those annoying problems
where getting two cards out can make life a little easier. With two kits you
could also hack up the extra 44-pin board to make a smaller
anders.e.e.wal...@gmail.com said:
Does it matter that the ADC in the sound-card is probably clocked by a
crystal clock that is 50ppm off and has bad ADEV?
You can calibrate the clock on the ADC.
One way is to feed a known reference frequency in on the other channel.
(That's assuming you
Hi
If you are mixing down to 10 Hz, and are looking for 1x10^-7 on the 10 Hz, that
equates to a stability / accuracy spec of 0.1 ppm on the ADC clock.
A 20 to 100 ppm offset on the clock is not all that unusual. Calibrating out
initial offset to 1 ppm is pretty simple. If you can poke a
HI
A little more information:
If you are doing the ADC thing, you still need to estimate zero crossings. In
all likelihood you would be doing bandpass filtering first (say 8 Hz to 12 Hz)
on your 10 Hz note. Next you would do some sort of estimator to get the zero
cross. A curve fit is one
kb...@n1k.org said:
If you are going to get any benefit from multiple antennas, you want to
space them as far apart as possible. You are better off with one antenna and
a splitter than with two close spaced antennas.
Does anybody have data? How would I measure it?
Where is the knee? I
HI
Many years ago, we got dinged on customer visit when they spotted our GPS
antenna array on the roof. The claim made at the time was that anything under
20’ spacing was counterproductive. I’ve seen numbers like 5, 8, 10,15 and 25
feet mentioned by different people at different times.
The
Robert,
Bob Camp mention Collins low jitter hard limiters but I suspect that's
much more of an issue on the very shallow slopes you see on 5 or 10 Hz
mixer outputs. The LTC6957 is probably overkill on 10 MHz inputs but I
believe they're a tad better than a 74AC gate, but then again maybe not
Hi,
Some attempts have been made. Never got around to write the needed code.
On 10/12/2014 08:37 PM, Hal Murray wrote:
anders.e.e.wal...@gmail.com said:
Does it matter that the ADC in the sound-card is probably clocked by a
crystal clock that is 50ppm off and has bad ADEV?
You can
Increasing the beat frequency to find a balance between 1/f noise and
f/delta-f amplification may be worth doing and have been seen done to
find optimum performance. If you use hard limiters or audio channels
to achieve it is however a little detail.
The benefit of audio channels is that the
Hi
The 1/F noise vs beat note “amplification” tradeoff is what pushes me up to 10
Hz rather than staying down around 1 Hz with most setups. It’s also a rational
offset to achieve at 10 MHz with common OCXO’s. Once you get past about 20 Hz,
your OCXO choices diminish.
Bob
On Oct 12, 2014, at
Bob,
I know, and I know you know. Just let others see how things connect up.
Still have some 10.000110 MHz OCXOs lying around.
Cheers,
Magnus
On 10/13/2014 02:15 AM, Bob Camp wrote:
Hi
The 1/F noise vs beat note “amplification” tradeoff is what pushes me up to 10
Hz rather than staying
Hi
If odd “almost 10 MHz OCXO’s were more common, you could indeed have a bit more
freedom on the offset. DDS is sometimes used. DDS spurs (which can be *very*
close in) can be both hard to predict and hard to spot in the data. An OCXO is
a much better bet unless you have a lot of time on your
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