Is a heatpipe really appropriate for this application? The heatpipe
expects that the heat source wants to burn up and so there's lots of
heat available to vaporize the liquid in the pipe. It's not clear to me
whether that situation exists with these Rb standards. My tests with an
FE-5680A
There is no question that direct fan control in combination with a heat
sink is the best solution and we use it on FRK and M 100 with proper thermal
insulation we get 0.01 C on the back plate and better than 0.1 C on the
front. For us the FE 5680 A is not in that class so we looked for a
Thanks for the info.
73, Dick, W1KSZ
On 8/17/2014 12:19 PM, paul swed wrote:
I did see John scooting along the road. The gates had not opened yet. But
did not see him after the gates did open.
It was a fairly small crowd
Regards
Paul
WB8TSL/1
On Sun, Aug 17, 2014 at 12:57 PM, Richard
My understanding is that the BFO and BTO values are self reported from the SDU
(Terminal in the aircraft) and they represent adjustments made by the SDU. If
so the BFO value would be the AFC adjustment relative to the OCXO onboard. My
contention is that if the investigators are assuming the
Good day all,
On another list to which I subscribe, there has been chatter about the Ublox
neo-7M GPS receiver. It seems that the device's configurable timepulse output
is configurable from 0.25hz to 10 MHz as well as it's duty cycle and can also
be set to be one condition when the GPS is not
Good day all,
On another list to which I subscribe, there has been chatter about the Ublox
neo-7M GPS receiver. It seems that the device's configurable timepulse
output is configurable from 0.25hz to 10 MHz as well as it's duty cycle and
can also be set to be one condition when the GPS is not
Graham,
Those are not GPSDO's by definition.
They are based on NCO technology.
The difference being many orders of magnitude higher phase noise and ADEV noise.
We tried to measure their phase noise and our TSC5125A could not even lock on
to the 10MHz - they were so noisy.
You can make a
Said,
Agreed, hence my reference as a very simple self-contained GPSDO.
Even after a very quick first glance at the documentation it didn't seem like
it would be much of threat to more traditional GPSDO's. It will be interesting
to play around with and see what it can do.
Cheers, Graham
Hi Graham,
its not a GPSDO though, not even a simple one :)
It does not discipline an oscillator. It generates the output by
mathematically calculating how many phases it has to add/drop in a second, then
digitally adds/drops/extends/retards the phase of the output clock to achieve
an
saidj...@aol.com said:
its not a GPSDO though, not even a simple one :)
It does not discipline an oscillator. It generates the output by
mathematically calculating how many phases it has to add/drop in a second,
then digitally adds/drops/extends/retards the phase of the output clock to
Hal,
I guess that depends on your definition of disciplined.
The products that I am familiar with don't consider adjusting phase length
of an asynchronously running oscillator on a cycle-to-cycle basis thousands
of times per second to try to fit 10 million of them (or whatever your
Hal, as long as you maintain long-term phase lock it's a disciplined
oscillator. So, yes, a carrier tracking WWVB receiver with sufficiently stable
flywheel LO is a WWVBDO.
Said, too-short or too-long 100 ns cycles is one thing. Still ok for many
applications. But tell me more about extra or
Knowing a litle bit about semiconductor production it is safe to assume
that all 7M series divvices have the same chip and during production at ublox
some features are disabled or enabled. The result is one mask set one chip
run and one inventory.
I did see a recent announcement where a 7M
Hi Tom,
last time I looked at these I tried figuring out what they were doing. It
is very hard to get measurement data, our TSC did not converge on their
signal, and looking at the output on a scope revealed only a bunch of crazy
random phase jumps. I guess one could use a counter to
Hi
They are constrained by the same basic TCXO issues that give you sawtooth
correction. They do not use EFC to get the TCXO on frequency. With sawtooth
they give you a word that lets you know what’s going on. With the NCO’s they
often are doing very crude synthesis. They don’t put a $48 DDS
As I understand it, Doppler will give you the magnitude of the velocity
vector for an aircraft with respect to the satellite, but it won't give
you the actual direction of the aircraft.
Why does the stability of the oscillators matter if you can't determine
the direction? Is there another
You CAN determine the ground track if you assume the altitude above
sea level is constant and the aircraft's speed is also constant. But
you are correct that Doppler alone would not be enough.
The question I have to people here is: How does error in the dopler
translate to error in the ground
On Tue, Aug 19, 2014 at 12:08:24PM -0400, Joe Leikhim wrote:
My understanding is that the BFO and BTO values are self reported from the
SDU (Terminal in the aircraft) and they represent adjustments made by the
SDU. If so the BFO value would be the AFC adjustment relative to the OCXO
I recall when the LEA-M8F was announced that they mentioned a VCTCXO and
maybe I wrongly assumed that they used it for sawtooth correction they also
mention ability to control in addition an external OCXO. I previously
suggested using saw tooth correction information to tune a TCXO but that
Does anyone have a neo-7M and an HP 5371A or a 5372A Analyzer? Use the
Histogram Time Interval function to measure a block of samples. That
will show the length of the samples with a resolution of 200 ps. That's
what I did a couple of years ago when I analyzed the Navsync CW-12 with
the old
Hi
There are only two things they can be doing (since it’s not a tuned oscillator).
1) It’s a true DDS with a D/A on the output and you need to put a filter on it
before you can do anything at all with it.
2) It’s a pulse drop / add NCO that drops or adds at the 20 to 30 ns level (28
to 50
Hi
If you have to womp up a MCU anyway, there is no reason to put in a delay chip.
It’s easier / faster / more accurate to just do it all in the MCU. You have to
write and maintain custom code either way.
Bob
On Aug 19, 2014, at 7:53 PM, ewkeh...@aol.com wrote:
I recall when the LEA-M8F
I raised this on the Duncan Steel website and was pretty much blown off.
Oh there is a nice stable OCXO aboard etc.
Well DUHH yes there is an OCXO aboard and if it is good to -20 to +75C,
or just -20 to +60C and there is a huge fire raging around it for an
hour, and then perhaps later the
Did measure NAA near Boston 8000uv using a dipole for 80 meters.
Looking at various vlf receivers it looks like a LPF or maybe a BPF filter
to a ne602 mixer followed by a tl081opamp LPF makes a direct conversion
receiver. Then hit the tracor d-msk-r.
Regards
Paul
WB8TSL
On Mon, Aug 18, 2014 at
I have a dozen ublox max-7's on hand and should have suitable PCB's
for the analysis in a couple of days. Unfortunately I don't have the
analyser, the test kit is currently limited to a HP5834A recently
calibrated to Rb and a 100MHz DSO so probably not what your looking
for.
Let me know if I
Bert wrote:
I guess time nuts like to talk about it but not fix it.
Will you PLEASE quit beating this tired old drum? All of us know
this is your opinion, although many of us have other explanations for
the phenomena you think it explains. We do not need you to repeat it
every time you
The total Doppler in this case is on the order of 100 Hz. The tiny
frequency shifts of an out of spec OCXO is just to small to measure.
The data says at UTC 18:30 the shift was in the mid range and was
about 175Hz. Assume the OCXO drifts 10 parts per million. That
is a lot for an OCXO.
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