Re: [time-nuts] Trimble Thunderbolt error

[Bob Camp]

Hi


…. also….

If it is a rollover bug, does it come back when the unit is power cycled or is 
there some magic in a
eprom that locks it to the correct era? (all of mine seem to be past  FW 3.00)

Bob

> On Feb 15, 2016, at 11:57 AM, Nigel Vander Houwen 
>  wrote:
> 
> Luc,
> 
> Do you have a reference for this?
> 
> Nigel
> 
>> On Feb 15, 2016, at 01:22, Luc Gaudin  wrote:
>> 
>> Hello, 
>> 
>> The issue was known on the Thunderbold for the older firmware version up to 
>> firmware v3.00.
>> The product will not report the correct extended GPS week number after the 
>> Feb,13th 2016.
>> After the rollover to week #860, the thunderbolt will not make position for 
>> 2 hours, because the Ephemeris data on the GPS receiver being consider 
>> incorrect.
>> The module will work fine after this 2 hours.
>> 
>> Regards,
>> 
>> Luc
>> 
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Re: [time-nuts] Trimble Thunderbolt error

[Nigel Vander Houwen]

Luc,

Do you have a reference for this?

Nigel

> On Feb 15, 2016, at 01:22, Luc Gaudin  wrote:
> 
> Hello, 
> 
> The issue was known on the Thunderbold for the older firmware version up to 
> firmware v3.00.
> The product will not report the correct extended GPS week number after the 
> Feb,13th 2016.
> After the rollover to week #860, the thunderbolt will not make position for 2 
> hours, because the Ephemeris data on the GPS receiver being consider 
> incorrect.
> The module will work fine after this 2 hours.
> 
> Regards,
> 
> Luc
> 
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[time-nuts] Trimble Resolution-T 52664-35

[Skip Withrow]

Hello Time-Nuts,

I just had a learning experience with the Trimble Resolution-T, so I
thought I would document it here and perhaps save time-nuts some time in
the future.  RDR Electronics has sold a number of telecom surplus
Resolution-T units (p/n- 52664-35) and we recently had a customer that said
he could not talk to the unit.  I fired one up and, sure enough, found the
exact same problem - no TSIP communications.  After a little
experimentation I found that I could communicate with the unit using
Trimble GPS Studio and that the unit was in TEP mode (a Trimble emulation
of the Motorola commands).  Unit is also 9600,N,8,1 (instead of Res-T
9600,O,8,1 default).

Apparently, the standard Trimble product is 52664-05.  The -35 units
identify as 'Timing Receiver' and have firmware 1.16.  There is a time-nut
archive that says you can change the mode to TSIP with GPS Studio, which I
successfully did, however I could never make it stick.  It seems that the
Save Changes issues some kind of reset that always puts it back in TEP mode
(before the TSIP mode is written to NVRAM).

So, to solve this problem I downloaded the Trimble 1.17 firmware (upgrade
from 1.14).  It does successfully load into the -35 units (despite the many
warnings in the documentation).  It identifies as a Resolution-T now and
defaults to TSIP at 9600,O,8,1.

The units that we are listing on ebay will have the 1.17 firmware loaded
into them (and will be tested).  If you purchase units from other vendors
with the 52664-35 part number be aware that they will most likely be in TEP
mode (unless they specifically address this issue).

Hope this information helps any prospective Trimble Resolution-T users.
They are nice receivers designed for timing applications - 3.3V,
12-channel, 1pps, with sawtooth correction output.

Regards,
Skip Withrow

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Re: [time-nuts] LIGO detects gravitational waves

[Attila Kinali]

On Mon, 15 Feb 2016 08:23:19 +0100
Magnus Danielson  wrote:

> I was thinking the same thing, the circulated energy isn't all that 
> great and each arm is feed with 10 W (it's a 20 W laser split in two).

The arms are fed with only 10W, but the circulating power is
actually 100kW. The arms are Fabry-Pérot cavities, i.e. resonators.

Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] Trimble Thunderbolt error

[Achim Vollhardt]

Dear all,

I can confirm total loss of GPS constellation here on Feb 14th,

going from 7 to 4 sats on 00:14:45 UTC
going to nil on 00:16:40 UTC

intermittent single sat tracking in between

back to 7 sats shortly after 02:00:00 UTC


I typically receive here between 5-8 sats with my Thunderbolt with fulll
horizon view of antenna.

So this seems to be a global issue.

Achim, DH2VA
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Re: [time-nuts] Trimble Thunderbolt error

[Achim Vollhardt]

I should add that I saw a similar disturbance of the force on my
Shera-type GPSDO. Cannot remember what GPS rx is installed but likely
some Jupiter-T model.

Cheers,
Achim

On 15.02.2016 08:08, Achim Vollhardt wrote:
> Dear all,
> 
> I can confirm total loss of GPS constellation here on Feb 14th,
> 
> going from 7 to 4 sats on 00:14:45 UTC
> going to nil on 00:16:40 UTC
> 
> intermittent single sat tracking in between
> 
> back to 7 sats shortly after 02:00:00 UTC
> 
> 
> I typically receive here between 5-8 sats with my Thunderbolt with fulll
> horizon view of antenna.
> 
> So this seems to be a global issue.
> 
> Achim, DH2VA
> 
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Re: [time-nuts] Trimble Thunderbolt error

[Luc Gaudin]

Hello, 

The issue was known on the Thunderbold for the older firmware version up to 
firmware v3.00.
The product will not report the correct extended GPS week number after the 
Feb,13th 2016.
After the rollover to week #860, the thunderbolt will not make position for 2 
hours, because the Ephemeris data on the GPS receiver being consider incorrect.
The module will work fine after this 2 hours.
 
Regards,

Luc

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Re: [time-nuts] LIGO detects gravitational waves

[Bill Byrom]

See the main paper in Physical Review Letters: *Observation of
Gravitational Waves from a Binary Black Hole Merger*
http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.061102

In figure 3 on page 4 you see a simplified diagram of the interferometer
setup. The text at the end of page 3 describes how the 20 W laser output
is increased to 700 W at the main beam splitter (by the power recycling
partially reflecting mirror) resulting in a 100 kW recirculating in the
two interferometer arm cavities. Strain on space-time at the detector
arms by the transverse gravitational wave tends to produce out of phase
length changes in the interferometer arms (depending on the polarization
and orientation of the wave relative to the detector arms). The high
finesse of the cavities causes the phase change due to a gravitational
wave at the beam splitter to be about 1,000 times greater than what you
would expect for a 8 km round-trip cavity length. The cavity response
time is probably around 26 us, so the phase build-up from repeated
reflections in the cavity can produce an effect within the bandwidth of
the signals being measured (under 1 kHz).

The system is carefully adjusted so that the two interferometer legs
produce a null at the beam splitter. A transverse gravitational wave of
the appropriate orientation and polarization produces a lengthening of
one leg and a shortening of the other, and after phase multiplication by
the cavity finesse the beam splitter is then slightly out of null and
emits a small signal. The next half cycle of the gravitational wave
produces another out of null condition in the opposite phase.

The finesse of the cavities makes the effective round-trip length of
each arm close to 8,000 km (rather than the actual 8 km round-trip
length). The reason for the power recycling is to improve the S/N at the
beam splitter. However, too much resonant power at various locations in
the system produces small movements of the mirrors due to very small
amplitude variations in the laser output. I'm sure that the actual
system is much more complex than the simplified diagram, and the years
of work which has been done improving these detectors has finally
improved the sensitivity so that a BBH (binary black hole) merger was
finally detected. Neutron star close binary orbits might also be
detected by this system.

For nearby objects (small redshifts), the volume of space in which such
a BBH merger could be detected is improved by the third power of the
detector sensitivity. Work is underway to improve the S/N by a factor of
3, which would increase the volume of space in which such objects could
be detected by a factor of 27. The current S/N with a matched filter was
24 for the GW150914 event, so I think they are very excited about
detecting many events per year. The current two-detector GW telescope
has poor angular resolution, since it can only tell that the GW source
was near a cone at a certain angle from the axis of the two detectors.
When three of more detectors with similar characteristics are in service
they can triangulate to give a single direction for the source.
Hopefully they will be able to correlate the results with X-ray,
optical, and/or radio telescopes in the future to identify the actual
source of the gravitational waves.

--
Bill Byrom N5BB
 
 
 
On Sun, Feb 14, 2016, at 02:26 PM, Paul Boven wrote:
> Hi PHK, everyone,
>  
> On 2016-02-14 0:30:22, Poul-Henning Kamp wrote:
>> 
>> In message <1E75A9592178425ABD11390EB725D060@pc52>, "Tom Van Baak" writes:
>>  
>>> Yes, the interferometer is 4 km in length but they bounce the beam back
>>> and forth 400 times so the effective length is more like 1600 km. They
>>> keep the mirrors stationary to "picometers". They use hundreds of clever
>>> tricks to pull this off.
>>  
>> It's actually more amazing than that, each arm is a resonant cavity,
>> so while the actual laser is only about 10W, they have about 20 kW of
>> photons inflight at any one time.
>>  
>> With 20 kiloWatt of light safety-glasses are not __that__ important any more.
>  
> This number keeps getting repeated, but I have some doubts there.
>  
> The 'finesse' of the cavity is about 1000. The view that the photons
> keep bouncing back and forth seems a bit simplistic, wouldn't it be more
> like a standing wave?
>  
> The cavity acts as a resonator, and although the instantaneous power
> would indeed be 20kW, as soon as you load that cavity, its stored energy
> would be dissipated in whoever was unlucky enough to end up in the beam.
> Given a length of 4km, it would take no more than 13 us to empty the
> cavity. And 13us times 20kW gives an energy of only 0.27 J.
>  
> The part that I am still having trouble understanding is why the two
> cavities in the arms of the interferometer help increase the
> sensitivity. Are they modulating the reflectivity of the mirrors on the
> inner testmasses so they can 'dump' both beams at the same time back
> into the half-silvered mirror?
>  
> 

Re: [time-nuts] HP Reliability

[Attila Kinali]

Moin,

Taking this off-list as this is getting far too OT.

On Sun, 14 Feb 2016 14:20:52 -0500
"William H. Fite"  wrote:

> They don't wonder; they know very well. But they're stuck. Consider
> oscilloscopes. Why pay for a Keysight or Tectronix or LeCroy or, God
> forbid, a Rohde & Schwarz when, for the vast majority of applications, a
> Rigol will give you everything you need at 1/N the cost?

No, it doesn't. A Rigol might be a usable replacement if you cannot
affort a real instrument, but it far from being something you want
to rely on. Yes, a Tek scope starts from 1000$ up while a Rigol is
half or even a third of that price. But you get all kind of weird
effects when you use a Rigol. Which means you are never exactly sure
whether you see an actual effect of your device or it's just some
weirdness of your measurement equipment. 

The price of Tek/Keysight/R does not come from the parts. By far not.
It comes from the fact that they ensure that you can measure with
confidence. Half of this is done by proper design (not only schematic,
but also layout and mechanics) and by doing extensive production tests that
do check for various problems, that are not easily seen.

When it comes to instruments where analog makes up 90% of the performance
and you cannot hide problems with digital processing, then Rigol
comes to the same price as the others.

Eg the DM3058 5.5 digit DMM costs 620€, that's just actually, 40€
more expensive than an U3402A. And mind you, the specs of the DM3058
are worse than that of the U3402A.

> The hugely expensive, overbuilt gear that we grew up with is yesterday's
> news; that's why we can scarf it up so cheap on the 'bay. Lots of labs and
> manufacturing facilities now consider basic gear like DSOs, SAs, DMMs,
> PSUs, and sig-gens as disposable as cell phones.

Definitly not. Yes, these have become basic gear you just have in an
electronics lab. But they are handled with care and you don't just buy
another if you just haven't have one at hand. Proper gear is investement.

Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] HP Reliability

[Poul-Henning Kamp]

In message , Bob Camp writes:

>there is a pretty long list of companies that had a good thing
>going through the 50’s and 60’s.

That "thing" is called "the cold war" where USA poured 10-20% of the
entire federal budget into high-tech and consequent innovations.


(while claiming to be a "capitalistic market economy" :-)

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Re: [time-nuts] LIGO detects gravitational waves

[Magnus Danielson]

Hi,

I was thinking the same thing, the circulated energy isn't all that 
great and each arm is feed with 10 W (it's a 20 W laser split in two).


The fact that it is a vacuum chamber of sizeable volume would make me 
avoid punching a hole in it for starters.


Considerining that they seemed to have a sample rate of 16384 Hz, they 
where keeping this operating this in relatively continuous mode or very 
high pulse-rate.


Cheers,
Magnus

On 02/14/2016 09:26 PM, Paul Boven wrote:

Hi PHK, everyone,

On 2016-02-14 0:30:22, Poul-Henning Kamp wrote:


In message <1E75A9592178425ABD11390EB725D060@pc52>, "Tom Van Baak"
writes:


Yes, the interferometer is 4 km in length but they bounce the beam back
and forth 400 times so the effective length is more like 1600 km. They
keep the mirrors stationary to "picometers". They use hundreds of clever
tricks to pull this off.


It's actually more amazing than that, each arm is a resonant cavity,
so while the actual laser is only about 10W, they have about 20 kW of
photons inflight at any one time.

With 20 kiloWatt of light safety-glasses are not _that_ important any
more.


This number keeps getting repeated, but I have some doubts there.

The 'finesse' of the cavity is about 1000. The view that the photons
keep bouncing back and forth seems a bit simplistic, wouldn't it be more
like a standing wave?

The cavity acts as a resonator, and although the instantaneous power
would indeed be 20kW, as soon as you load that cavity, its stored energy
would be dissipated in whoever was unlucky enough to end up in the beam.
Given a length of 4km, it would take no more than 13 us to empty the
cavity. And 13us times 20kW gives an energy of only 0.27 J.

The part that I am still having trouble understanding is why the two
cavities in the arms of the interferometer help increase the
sensitivity. Are they modulating the reflectivity of the mirrors on the
inner testmasses so they can 'dump' both beams at the same time back
into the half-silvered mirror?

Cheers, Paul - 73 de PEaNUT.



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[time-nuts] SR620

[Joseph Gray]

OK, who got the SR620 with the "test error 34"? From looking at the
manual, it may simply be user error and the instrument may be just
fine. If you are the buyer, I hope that is true and that you got a
bargain. I took a stab at buying it, but wasn't willing to chance too
much, in case there was something seriously wrong with it.


Joe Gray
W5JG
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