lmcda...@lmceng.com said:
> To make this very long story into a short one, I learned that the HP/
> Symmetricom 58532A GPS Reference (timing) antennas use a simple patch
> antenna instead of a quadrafilar antenna and that old solder flux residue
> will attenuate the even amplified GPS signal
Correct, Dan- nothing received-still interested though, if something pops up.
Unit is still here and a friend has a sidereal version but no data.
DaveB, NZ
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Dan Veeneman
Sent: Saturday, May 12, 2018 11:38
WSJ had review of The Perfectionists by Simon Winchester May 5-6( Books).
Sounds right up this group's alley. As the reviewer states, it: corrals a
large cast of eccentric individuals." Many of which it might have been fun to
spend time with. I've read a few of his other 29 books and most
Hi:
Here's some great ideas from Clifford Stoll:
https://www.ted.com/talks/clifford_stoll_on_everything?language=en
The transcript is available in 27 languages.
PS He has an on line business selling Klein Bottles (some with calibration
certificates:)
http://www.kleinbottle.com/
I got a
Thanks, Dave, for reporting your failed GPS antenna; at least, I am not
alone in having this failure.
It will be interesting to understand what you find when you open your
failed 58532A. Removing the radome is very easy, just 4 screws and some
wiggling or gentle prying. If yours does not have
Using a pendulum to measure gravity requires precision timekeeping.
Wikipedia has a nice discussion of this at
https://en.wikipedia.org/wiki/Pendulum#Gravity_measurement
There are number of very clever techniques developed long ago, such as
Henry Kater's design for a reversible, dual pivot
At telecom wavelengths GDD can be quite low.
Laser source spectral widths can also be low.
At visible wavelengths an fiber length imbalance of 1m with a 1nm bandwidth
light source makes interferometry impossible/difficult without GDD compensation
even if delays are matched.
The moodulation
How about a demonstration of how GPS works, substituting sound waves for
radio ?
Maybe three sound sources with harmonically-related frequencies, then
measure their phase difference on an oscilloscope.
Cheat a bit : you don't need to do cdma acquisition. Have one reference at
a low frequency,
Indeed; however, with single mode fiber the limit is not too bad. At
Arecibo we routinely ran bandwidths in
excess of 1 GHz through fibers of about 1500 ft length with no problems.
For the science fair project a
bandwidth of a few MHz should suffice for lengths of, say, 500 ft. It's
just that I
Would it be too simple a project to have a GPS demonstration:
* GPS time, leap seconds (need for)
* UTC time
* Local Time Zone time (rise, set, noon)
* Solar Time (rise, set, noon)
* Solid Earth Tides
* and a custom sun dial, marked for solar time and local time (a lamp
can simulate
Even with single mode fiber its finite group delay dispersion will likely
restrict the usable light source bandwidth.
Bruce
> On 13 May 2018 at 03:38 Dana Whitlow wrote:
>
>
> It may be that a nicely-written request to Corning could yield the loan of
> a big spool of
Like this so called star target?:
https://www.edmundoptics.com/test-targets/resolution-test-targets/1-black-1-white-glass-star-target-5deg-wedge-pair-angle/
Bruce
> On 13 May 2018 at 02:45 Bob kb8tq wrote:
>
>
> Hi
>
>
>
> > On May 12, 2018, at 7:01 AM, jimlux
On 05/12/2018 09:41 PM, Bob kb8tq wrote:
> Hi
>
>
>> On May 12, 2018, at 1:20 PM, Oleg Skydan wrote:
>>
>> Hi!
>>
>> From: "Bob kb8tq"
>>> There is still the problem that the first post on the graph is different
>>> depending
>>> on the technique.
>>
>>
Hi,
On 05/12/2018 08:38 PM, Oleg Skydan wrote:
> Hi!
>
> From: "Magnus Danielson"
>> ADEV assumes brick-wall filtering up to the Nyquist frequency as result
>> of the sample-rate. When you filter the data as you do a Linear
>> Regression / Least Square estimation,
Hi
As mentioned a number of times, quadrafilar antennas were only popular for a
very short
while back in the 1980’s. Once people started using GPS for “stuff” they
rapidly lost out in
the antenna race. They were made popular by an early NIST paper. Later on NIST
effectively
said “oops !!” in
I recently had an unexpected failure of a white-conical-dome
HP/Symmetricom 58532A GPS antenna that had been in-place about 5 feet
above the roof of my two-story home in Southern California for about ten
years. I have two similar GPS antennas located about ten feet apart on
this roof, one fed
Hi
> On May 12, 2018, at 1:20 PM, Oleg Skydan wrote:
>
> Hi!
>
> From: "Bob kb8tq"
>> There is still the problem that the first post on the graph is different
>> depending
>> on the technique.
>
> The leftmost tau values are skipped and they "stay"
Hi
There are places that sell them. Most are looking for a couple thousand dollars
for
one. If that is inside your budget you might get in touch with them. Far
cheaper to
get an eBay scrap OCXO and use its parts.
An OCXO depends on the combination of two things to make it stable:
1) The
Hi Oleg,
On 05/12/2018 07:20 PM, Oleg Skydan wrote:
> Hi!
>
> From: "Bob kb8tq"
>> There is still the problem that the first post on the graph is
>> different depending
>> on the technique.
>
> The leftmost tau values are skipped and they "stay" inside the counter.
> If I setup
Hi!
From: "Magnus Danielson"
ADEV assumes brick-wall filtering up to the Nyquist frequency as result
of the sample-rate. When you filter the data as you do a Linear
Regression / Least Square estimation, the actual bandwidth will be much
less, so the ADEV measures
Julien
Yes you could stabilize the temperature at some level.
But your really adding complexity that will tend to interact.
You have the natural TCXO behavior and then the oven behavior. Hard to say
how it all will behave.
But I suspect your suggesting warming the TCXO to something in its best
Hi!
From: "Bob kb8tq"
There is still the problem that the first post on the graph is different
depending
on the technique.
The leftmost tau values are skipped and they "stay" inside the counter. If I
setup counter to generate lets say 1s stamps (ADEV starts at 1s) it will
Does anyone know if there's anyone who sells essentially just the oven &
casing for an OCXO on its own?
I have a project for which I'm currently using a VCTCXO, but I'm
wondering if enclosing a plain VCXO, plus the control DAC & voltage
reference in a single small oven would end up more stable,
It may be that a nicely-written request to Corning could yield the loan of
a big spool of fiber
for the duration of a science fair project.
Another alternative, perhaps easier to implement, might be an
electrically-driven light modulator
at the detector end. For the source, an LED or diode
How about a Stroboscope? -
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115
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Hi
> On May 12, 2018, at 7:01 AM, jimlux wrote:
>
> On 5/11/18 9:08 PM, Jeff Woolsey wrote:
>> David.vanhorn wrote:
>>> Measuring the speed of light (Fizeau or Michelson method? Other ways)
>>>
>>>
>>> I saw a great demo of this at the Exploratorium in SF. They had a
Hi
Ok, the gizmo on the front it an Altera CPLD. Not a lot of gates, so not a lot
going
on there. Whatever the real functions are, they are in the chip with no
labeling.
Even with the full information (let’s say):
Takes in a 16 stream OC-blah blah and provides the following alarms on the
Today using Lady Heather I have observed the TruePostion GPSDO dropping into
holdover as the number of tracked sats dropped from four to three.
There does seem to be some hysteresis in the system though, the number of
tracked sats eventually dropped to two and then the unit came out of holdover
On 5/11/18 9:08 PM, Jeff Woolsey wrote:
David.vanhorn wrote:
Measuring the speed of light (Fizeau or Michelson method? Other ways)
I saw a great demo of this at the Exploratorium in SF. They had a long spool
of fiber optic, a disc with holes, and a light source. When static, if the
light
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