Re: [time-nuts] Good GPSDO on eBay?

[Charles Steinmetz]

Mark wrote:


Charles,

You are confusing these units with those made by that ham in China (can't remember his 
callsign, begins with a "B").   The guts of these boxes is a telco GPDDO board 
made by either Trimble or Symmetricom (you can tell because of the 6.0V power 
requirement).And that reference to a Thunderbolt in his Ebay listing seems to refer 
to him comparing the output of these  to his Thunderbolt,  not that the oscillator in 
them came out of a Thunderbolt.


Thanks, Mark, I stand corrected.  That also means it will have a PLL, 
not an FLL.


How good is the OCXO? Can you adjust the loop tuning parameters for best 
stability with the individual OCXO?  If not, does the loop cross over 
from the OCXO to the GPS at an appropriate tau, or does it exhibit the 
notorious "crossed over too early" hump in the xDEV plots?  Does it 
store its surveyed location or does it need to do a new survey every 
time it is powered up?


Finally, is there a good reason to pay $160 for one the seller has put 
in a box, or can you buy the board for much less and do that yourself?


Best regards,

Charles


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Re: [time-nuts] Good GPSDO on eBay?

[Charles Steinmetz]

Michael wrote:


I think what the seller saying is that the counter was externally
referenced to the Thunderbolt for the frequency measurements
that they state.


Yes, on re-reading the listing, I believe you are right.  Thanks!

Charles


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Re: [time-nuts] Does doubling a frequency alter the original ADEV of the frequency?

[Charles Steinmetz]

David wrote:


Thanks for the reminder about this... it will neatly solve a problem I
have at hand. Can you advise which core you used for the transformer?


If you mean the quadrature hybrid, I use an FT37-61 toroid core.  One of 
the smaller Mix 61 balun cores should also work, but with the toroid you 
can trim the inductance by spreading or compacting the windings on the 
core.


If you mean the transformers for the push-push FET doubler, I usually 
use commercial parts (MCL or Coilcraft).


Best regards,

Charles


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Re: [time-nuts] Good GPSDO on eBay?

[Chris Albertson]

On Sat, Jul 9, 2016 at 5:51 PM, Richard W. Solomon 
wrote:

> What a deal, if it arrives DOA, return shipment is on
> your nickel. I would look elsewhere.


That is not true.  If it were DOA and the seller would not take it back
post paid you could file a "not as described" on the seller and eBay would
refund the price.  eBay and Paypal offer pretty good buyer protection.

Someone here said the seller uses multiple IDs.  It is more likely that one
person is making these and offering to multiple people who  then sell them
on eBay.   This is the way it works in China, a popular design gets made
and then is sold by many people.   It is all a cottage industry over there.
   Pick any kind of electronic PCB level part, say a stepper motor driver
and you see the same exact part from 20 different sellers not one seller
with 20 IDs.(Well that is the general case, this specific one might be
different, who knows.)

But so what even if the GPSDO is good only to 1xE10 that is still a very
useful device to own.  Yes some are literally 1,000 times better

You could always build your own.  It is not hard nor is it expensive if you
have a reasonable goal and don't go for state of the art.
-- 

Chris Albertson
Redondo Beach, California
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[time-nuts] Good GPSDO on eBay?

[Mark Sims]

All the affordable GPSDOs out there are surplus telecom devices...  
Thunderbolts,  Z38xx's,  NTP, etc.   They were built to rigorous telco 
standards and can be excellent performers.  Just because they are surplus, does 
not make them junk.   

The latest round of surplus GPSDOs to hit the market are these "UCCM" units.   
They started out at around $50 and after people figured out what they were and 
how to use them the price jumped to $100+ (Thunderbolts and Z3801A's did the 
same thing,  now a surplus one can set you back  $300-$400.  I suspect that 
these will follow the same path) You can find the UCCM devices as bare boards 
or built up into boxes.   As far as real money,  a surplus $100 unit or new 
$500+ unit?  What's in your wallet?  The UCCM based devices should not be 
confused with or compared to some home-brew GPSDO cobbled together in a similar 
looking box. 

--
> Recycled components sold for real money.
Too many "versions" to figure out "what you got".
If all you want is a frequency standard to turn it on and "forget it" 
spend a few extra bucks and get one with all new components from a 
domestic company. 
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Re: [time-nuts] Good GPSDO on eBay?

[bownes]

To paraphrase a few other folks, taking on the task of building your own, even 
using the VE2ZAZ board as a basis is a very educational experience. It will 
teach you an enormous amount. There are lessons in control systems, phase and 
frequency locked loops, oven controllers, phase and frequency measurement, and 
doubtless lots of things I've overlooked. 

Well worth the effort. 

> On Jul 9, 2016, at 23:06, Bob Stewart  wrote:
> 
> But, as a starter GPSDO, probably anything is good.  Frequency accuracy, even 
> if a fraction of a Hz off, is all you're looking for at first.  I bought one 
> of Bert Zauhar's (VE2ZAZ) circuit boards and chips for my first one.  It was 
> a good experience.  And when I was done, I had a GPSDO that was as good as 
> most of what you find on ebay in the bargain basement, but at a much lower 
> cost.  But then you need a case, and something to compare it to, and 
> something even better, and then you're a time-nut.
> 
> But 
> 
> 
> At 04:40 PM 7/9/2016, Richard Mogford wrote:
>> This looks like a good beginner's GPSDO on eBay: 172148560746
>> 
>> "This is GPS Disciplined Clock made with trimble GPSDO Board.Full 
>> tested by Agilent 53132A with US-012 option and Ex-ref from trimble 
>> thunderbolt GPSDO."
>> 
>> 
>>   The seller says it has a sine wave output and is accurate from
>>   10e-11 to 10e-12.
>> 
>> Any thoughts?
>> 
>> Richard
>> 
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Re: [time-nuts] Good GPSDO on eBay?

[Bob Stewart]

And when you build your own, you're still left with the issue of the 
oscillator.  In my experience, only about 2 out of 3 of the 34310-Ts I get from 
China are worth using.  If you buy them one at a time your odds aren't good.  
OTOH, as your first oscillator, especially for HF use, noise and stability 
aren't quite as important as if you're multiplying up to microwaves.

But, as a starter GPSDO, probably anything is good.  Frequency accuracy, even 
if a fraction of a Hz off, is all you're looking for at first.  I bought one of 
Bert Zauhar's (VE2ZAZ) circuit boards and chips for my first one.  It was a 
good experience.  And when I was done, I had a GPSDO that was as good as most 
of what you find on ebay in the bargain basement, but at a much lower cost.  
But then you need a case, and something to compare it to, and something even 
better, and then you're a time-nut.

But one thing to remember Richard, is that the time-nuts idea of accuracy is 
much different from what you may be used to.  For HF ham use,+/- 1Hz accuracy 
is a big deal.  In the time nuts community, phase accuracy to the nanosecond 
level (and even better, if possible!) is what's important.

Bob
 -
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info

  From: Dimitri.p 
 To: Discussion of precise time and frequency measurement ; 
time-nuts@febo.com 
 Sent: Saturday, July 9, 2016 9:14 PM
 Subject: Re: [time-nuts] Good GPSDO on eBay?
   
since you asked ...
Many thoughts, none of them good.
Recycled components sold for real money.
Too many "versions" to figure out "what you got".
If all you want is a frequency standard to turn it on and "forget it" 
spend a few extra bucks and get one with all new components from a 
domestic company.
Or if you want to have some fun put together one of your own.



At 04:40 PM 7/9/2016, Richard Mogford wrote:
>This looks like a good beginner's GPSDO on eBay: 172148560746
>
>"This is GPS Disciplined Clock made with trimble GPSDO Board.Full 
>tested by Agilent 53132A with US-012 option and Ex-ref from trimble 
>thunderbolt GPSDO."
>
>
>      The seller says it has a sine wave output and is accurate from
>      10e-11 to 10e-12.
>
>Any thoughts?
>
>Richard
>
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Re: [time-nuts] Good GPSDO on eBay?

[Charles Steinmetz]

Richard wrote:


This looks like a good beginner's GPSDO on eBay: 172148560746

"This is GPS Disciplined Clock made with trimble GPSDO Board.Full tested
by Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt
GPSDO."

  The seller says it has a sine wave output and is accurate from
  10e-11 to 10e-12.

Any thoughts?


It is very hard to say exactly what you will get, because the seller 
(who uses a dozen or more different ebay IDs) seems to change the design 
every time the wind shifts.  But typically they are FLLs (frequency 
locked loops), not genuine PLLs (phase locked loops), and have a small 
frequency offset because the design does not address some systemic 
issues of FLL design.  It is unlikely to deliver better than 10e-11 
performance with any certainty.


In addition to that, if  "Ex-ref from trimble thunderbolt GPSDO" is 
supposed to make a buyer think it will have the best Trimble OCXO (P/N 
37265), the one that was in the Trimble Thunderbolts of list legend, 
that is almost certainly false.  It may have a Trimble-branded OCXO, but 
even if it does it will be one of the many lesser part numbers.


To me, the attempts to mislead buyers is enough, by itself,  to rule out 
dealing with that seller, under any of his ebay IDs.


Best regards,

Charles


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Re: [time-nuts] Good GPSDO on eBay?

[Dimitri.p]

since you asked ...
Many thoughts, none of them good.
Recycled components sold for real money.
Too many "versions" to figure out "what you got".
If all you want is a frequency standard to turn it on and "forget it" 
spend a few extra bucks and get one with all new components from a 
domestic company.

Or if you want to have some fun put together one of your own.



At 04:40 PM 7/9/2016, Richard Mogford wrote:

This looks like a good beginner's GPSDO on eBay: 172148560746

"This is GPS Disciplined Clock made with trimble GPSDO Board.Full 
tested by Agilent 53132A with US-012 option and Ex-ref from trimble 
thunderbolt GPSDO."



 The seller says it has a sine wave output and is accurate from
 10e-11 to 10e-12.

Any thoughts?

Richard

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[time-nuts] Good GPSDO on eBay?

[Mark Sims]

Charles,

You are confusing these units with those made by that ham in China (can't 
remember his callsign, begins with a "B").   The guts of these boxes is a telco 
GPDDO board made by either Trimble or Symmetricom (you can tell because of the 
6.0V power requirement).And that reference to a Thunderbolt in his Ebay 
listing seems to refer to him comparing the output of these  to his 
Thunderbolt,  not that the oscillator in them came out of a Thunderbolt.

--
> It is very hard to say exactly what you will get, because the seller 
(who uses a dozen or more different ebay IDs) seems to change the design 
every time the wind shifts.  But typically they are FLLs (frequency 
locked loops), not genuine PLLs (phase locked loops), and have a small 
frequency offset because the design does not address some systemic 
issues of FLL design.  It is unlikely to deliver better than 10e-11 
performance with any certainty.
  
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Re: [time-nuts] Good GPSDO on eBay?

[Michael Wouters]

"Full tested by Agilent 53132A with US-012 option and Ex-ref from
trimble thunderbolt
GPSDO."

I think what the seller saying is that the counter was externally
referenced to the Thunderbolt for the frequency measurements that they
state.

Cheers
Michael

On Sun, Jul 10, 2016 at 10:58 AM, Charles Steinmetz
 wrote:
> Richard wrote:
>
>> This looks like a good beginner's GPSDO on eBay: 172148560746
>>
>> "This is GPS Disciplined Clock made with trimble GPSDO Board.Full tested
>> by Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt
>> GPSDO."
>>
>>   The seller says it has a sine wave output and is accurate from
>>   10e-11 to 10e-12.
>>
>> Any thoughts?
>
>
> It is very hard to say exactly what you will get, because the seller (who
> uses a dozen or more different ebay IDs) seems to change the design every
> time the wind shifts.  But typically they are FLLs (frequency locked loops),
> not genuine PLLs (phase locked loops), and have a small frequency offset
> because the design does not address some systemic issues of FLL design.  It
> is unlikely to deliver better than 10e-11 performance with any certainty.
>
> In addition to that, if  "Ex-ref from trimble thunderbolt GPSDO" is supposed
> to make a buyer think it will have the best Trimble OCXO (P/N 37265), the
> one that was in the Trimble Thunderbolts of list legend, that is almost
> certainly false.  It may have a Trimble-branded OCXO, but even if it does it
> will be one of the many lesser part numbers.
>
> To me, the attempts to mislead buyers is enough, by itself,  to rule out
> dealing with that seller, under any of his ebay IDs.
>
> Best regards,
>
> Charles
>
>
>
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Re: [time-nuts] Does doubling a frequency alter the original ADEV of the frequency?

[davidh]

Charles,

Thanks for the reminder about this... it will neatly solve a problem I 
have at hand. Can you advise which core you used for the transformer?


Thanks,

david


On 10/07/2016 07:57, Charles Steinmetz wrote:

James wrote:


Is there a preferred frequency doubler circuit which would do the
least harm to the ADEV of the oscillator?  The signal can be a square
wave and does not need to be a sine wave.  Thanks.  Jim Robbins


A quadrature-fed DBM produces the lowest jitter and noise.  My
implementation can be found at:




A well-designed push-push frequency doubler is probably second (but note
that many push-push designs you find on the web have various common
design flaws).  My implementation can be found at:




Best regards,

Charles





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Re: [time-nuts] Good GPSDO on eBay?

[Richard W. Solomon]

What a deal, if it arrives DOA, return shipment is on 
your nickel. I would look elsewhere.

73, Dick, W1KSZ

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Richard Mogford
Sent: Saturday, July 09, 2016 4:40 PM
To: time-nuts@febo.com
Subject: [time-nuts] Good GPSDO on eBay?

This looks like a good beginner's GPSDO on eBay: 172148560746

"This is GPS Disciplined Clock made with trimble GPSDO Board.Full tested by 
Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt GPSDO."


  The seller says it has a sine wave output and is accurate from
  10e-11 to 10e-12.

Any thoughts?

Richard

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Re: [time-nuts] GPS disciplined Mars clock

[Bob Camp]

Hi

…. but what time is it on Titan  :)

Bob

> On Jul 9, 2016, at 6:35 PM, Mark Sims  wrote:
> 
> I just added code to Lady Heather to calculate time in Terrestrial Time (TT) 
> and Geocentric Terrestrial Time (TCG).   The difference is basically the time 
> dilation effect of a time referenced to the center of the earth.   Now  I'm 
> adding Barycentric Dynamic Time (TDB) which is TT referenced to the center of 
> the solar system... basically another relativistic correction.
> Does anybody know of an online TT/TCG/TDB clock?  I can't seem to find one to 
> check my math.
> I've also added Mercury/Venus/Pluto time/date... which I've arbitrarily 
> defined as GPS seconds since the J1900 astronomical epoch divided by the 
> orbital period.  I decided not to do times for those squishy gas-bag planets.
> 
> ---
>> Hmm,  gravitational time dilation it might complicate things ...  I
> suppose it depends on whether your Mars clock is on the surface of Mars,
> Earth or somewhere else.
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[time-nuts] Good GPSDO on eBay?

[Mark Sims]

They are based upon a telco surplus "UCCM" GPSDO board.   Both Symmetricom and 
Trimble made (mostly) compatible units.  I prefer the Trimble units...  they 
store their settings in EEPROM.  The Symmetricom units don't... and have to do 
a long re-survey every time you power them up.   Plus the firmware in the 
Symmetricom units has a couple of minor glitches (occasionally drops a time 
stamp output message and can send the time stamp message in the middle of other 
message outputs).   That said,  the Symmetricom is rumored to have a slightly 
better oscillator)... but it is driven by a 6V to 12V DC-DC converter that is 
known to be somewhat unreliable.  I have not measured the output ADEVs, etc.


A little shopping on Ebay (search Trimble GPSDO) will turn up some units for 
less money.   I bought one of these and it arrived quickly and safely in good 
condition (BTW, you used to be able to get them for $50):
http://www.ebay.com/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-/121966793020?hash=item1c65c9913c:g:TTgAAOSwVllXHYRU
There are unscrupulous sellers shipping damaged units.

This thread on EEVBLOG covers the units pretty well:
http://www.eevblog.com/forum/projects/a-look-at-my-symmetricom-gpsdo-(ocxo-furuno-receiver)/

I now have Lady Heather working with both models.

  
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Re: [time-nuts] GPS disciplined Mars clock

[Bob Camp]

Hi

Obviously time for a Kickstarter campaign to put a set of observatories on Mars 
….

Bob

> On Jul 9, 2016, at 5:59 PM, jimlux  wrote:
> 
> On 7/9/16 1:40 PM, Joe Fitzgerald wrote:
>> 
>> 
>> On 7/9/2016 3:00 PM, jimlux wrote:
>>> 
>>> TAI my friend, TAI...
>>> 
>> Hmm,  gravitational time dilation it might complicate things ...  I
>> suppose it depends on whether your Mars clock is on the surface of Mars,
>> Earth or somewhere else.
>> 
>> 
>> On 7/9/2016 3:34 PM, Hal Murray wrote:
>>> 
>>> How good is the data on the rotation rate for Mars?  Is it good enough so
>>> that they would need leap seconds?
>>> 
>>> 
>> 
>> Without an ocean or significant atmosphere I bet the rotation rate would
>> be more predictable than Earth - once good measurements were made.  The
>> dearth of observatories on Mars suggests the current error bars on
>> current rate estimates pretty wide.
> 
> 
> I'd guess the rate estimate is quite good.  Wikipedia says
> 88,775.24409 seconds/sol
> 
> We can do very good ranging to MER and MSL.  Phoenix didn't carry a direct to 
> earth transponder.
> 
> We can also do ranging from rovers to MRO, and then from MRO to Earth. I 
> don't know how much ranging we've done at UHF, though.  The radio wasn't 
> really designed for it, so the math gets a bit complex, and I'm not sure you 
> can back out all the higher order terms.  The UHF radio on MRO does have a 
> USO driving it, so it's timing performance should be quite good in "open loop 
> record" mode.
> 
> The uncertainty in the MRO range & range rate is probably less than for the 
> rovers, because the SNR is much better (big multi-meter antenna on MRO helps 
> a lot).
> 
> 
>> 
>> Fun to think about that's for sure.
>> 
>> -Joe
>> 
>> ---
>> This email has been checked for viruses by Avast antivirus software.
>> https://www.avast.com/antivirus
>> 
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Re: [time-nuts] Does doubling a frequency alter the original ADEV of the frequency?

[Charles Steinmetz]

James wrote:


Is there a preferred frequency doubler circuit which would do the least harm to 
the ADEV of the oscillator?  The signal can be a square wave and does not need 
to be a sine wave.  Thanks.  Jim Robbins


A quadrature-fed DBM produces the lowest jitter and noise.  My 
implementation can be found at:




A well-designed push-push frequency doubler is probably second (but note 
that many push-push designs you find on the web have various common 
design flaws).  My implementation can be found at:




Best regards,

Charles


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[time-nuts] Good GPSDO on eBay?

[Richard Mogford]

This looks like a good beginner's GPSDO on eBay: 172148560746

"This is GPS Disciplined Clock made with trimble GPSDO Board.Full tested 
by Agilent 53132A with US-012 option and Ex-ref from trimble thunderbolt 
GPSDO."



 The seller says it has a sine wave output and is accurate from
 10e-11 to 10e-12.

Any thoughts?

Richard

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Re: [time-nuts] Does doubling a frequency alter the original ADEV of the frequency?

[Bob Camp]

Hi

The simple answer is that most doublers that are ok for phase noise will not 
degrade ADEV. 
The issues with ADEV come when your doubler is out in a changing environment 
and your 
oscillator is not ( = it’s an OCXO). The answer to that problem is pretty 
simple if you have an issue …
ovenize the doubler.

Bob

> On Jul 9, 2016, at 3:48 PM, James Robbins  wrote:
> 
> Would doubling the frequency of a 5 MHz oscillator to 10 MHz affect (or 
> degrade) the natural ADEV of the 5 MHz oscillator?  If so, how does it affect 
> the original ADEV?  Is there a preferred frequency doubler circuit which 
> would do the least harm to the ADEV of the oscillator?  The signal can be a 
> square wave and does not need to be a sine wave.  Thanks.  Jim Robbins
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[time-nuts] GPS disciplined Mars clock

[Mark Sims]

I just added code to Lady Heather to calculate time in Terrestrial Time (TT) 
and Geocentric Terrestrial Time (TCG).   The difference is basically the time 
dilation effect of a time referenced to the center of the earth.   Now  I'm 
adding Barycentric Dynamic Time (TDB) which is TT referenced to the center of 
the solar system... basically another relativistic correction.
Does anybody know of an online TT/TCG/TDB clock?  I can't seem to find one to 
check my math.
I've also added Mercury/Venus/Pluto time/date... which I've arbitrarily defined 
as GPS seconds since the J1900 astronomical epoch divided by the orbital 
period.  I decided not to do times for those squishy gas-bag planets.

---
> Hmm,  gravitational time dilation it might complicate things ...  I
suppose it depends on whether your Mars clock is on the surface of Mars,
Earth or somewhere else.  
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Re: [time-nuts] GPS disciplined Mars clock

[jimlux]

On 7/9/16 1:40 PM, Joe Fitzgerald wrote:



On 7/9/2016 3:00 PM, jimlux wrote:


TAI my friend, TAI...


Hmm,  gravitational time dilation it might complicate things ...  I
suppose it depends on whether your Mars clock is on the surface of Mars,
Earth or somewhere else.


On 7/9/2016 3:34 PM, Hal Murray wrote:


How good is the data on the rotation rate for Mars?  Is it good enough so
that they would need leap seconds?




Without an ocean or significant atmosphere I bet the rotation rate would
be more predictable than Earth - once good measurements were made.  The
dearth of observatories on Mars suggests the current error bars on
current rate estimates pretty wide.



I'd guess the rate estimate is quite good.  Wikipedia says
88,775.24409 seconds/sol

We can do very good ranging to MER and MSL.  Phoenix didn't carry a 
direct to earth transponder.


We can also do ranging from rovers to MRO, and then from MRO to Earth. 
I don't know how much ranging we've done at UHF, though.  The radio 
wasn't really designed for it, so the math gets a bit complex, and I'm 
not sure you can back out all the higher order terms.  The UHF radio on 
MRO does have a USO driving it, so it's timing performance should be 
quite good in "open loop record" mode.


The uncertainty in the MRO range & range rate is probably less than for 
the rovers, because the SNR is much better (big multi-meter antenna on 
MRO helps a lot).





Fun to think about that's for sure.

-Joe

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Re: [time-nuts] GPS disciplined Mars clock

[jimlux]

On 7/9/16 12:34 PM, Hal Murray wrote:


jfitzger...@alum.wpi.edu said:

What organization is in charge of inserting leap seconds into the Martian
time scale?


How good is the data on the rotation rate for Mars?  Is it good enough so
that they would need leap seconds?


Very good. We can do two way Doppler from the Mars Rovers with an 
accuracy in the mm/s range, and from that get a very good rotation rate.





How about leap years/days?  (assuming they have a calandar)



That would depend on whether the Martian year is an exact multiple of 
the Martian sol (which I suspect it is not), and then, whether you want 
your calendar to align with some astronomical event (e.g. a solstice).



https://en.wikipedia.org/wiki/Timekeeping_on_Mars

1 mars sidereal year = 668.5991 sols



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Re: [time-nuts] GPS disciplined Mars clock

[Joe Fitzgerald]

On 7/9/2016 3:00 PM, jimlux wrote:
>
> TAI my friend, TAI...
>
Hmm,  gravitational time dilation it might complicate things ...  I
suppose it depends on whether your Mars clock is on the surface of Mars,
Earth or somewhere else.


On 7/9/2016 3:34 PM, Hal Murray wrote:
>
> How good is the data on the rotation rate for Mars?  Is it good enough so 
> that they would need leap seconds?
>
>

Without an ocean or significant atmosphere I bet the rotation rate would
be more predictable than Earth - once good measurements were made.  The
dearth of observatories on Mars suggests the current error bars on
current rate estimates pretty wide.

Fun to think about that's for sure.

-Joe

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Re: [time-nuts] GPS disciplined Mars clock

[Hal Murray]

jfitzger...@alum.wpi.edu said:
> What organization is in charge of inserting leap seconds into the Martian
> time scale? 

How good is the data on the rotation rate for Mars?  Is it good enough so 
that they would need leap seconds?

How about leap years/days?  (assuming they have a calandar)

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[time-nuts] jovian and saturnian day length

[jimlux]

http://www.space.com/4314-length-saturn-day-revised.html

They measure some presumed solid(ish) center.

If the magnetic field axis and the rotation axis are displaced, you can 
measure when the magnetic field goes by.  Or by radio sources.


Jupiter day length at the poles is slightly longer than day length at 
equator, but it's about 1% 9 hr 56 min vs 9 hr 50 min.


I figure the Jupiter day length (which has been given as about 10 hours 
for a very long time, certainly before we sent spacecraft nearby) is 
probably from visual observation of the Great Red Spot.  You can easily 
see it move in a not very big telescope over the course of a night.

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[time-nuts] Does doubling a frequency alter the original ADEV of the frequency?

[James Robbins]

Would doubling the frequency of a 5 MHz oscillator to 10 MHz affect (or 
degrade) the natural ADEV of the 5 MHz oscillator?  If so, how does it affect 
the original ADEV?  Is there a preferred frequency doubler circuit which would 
do the least harm to the ADEV of the oscillator?  The signal can be a square 
wave and does not need to be a sine wave.  Thanks.  Jim Robbins
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Re: [time-nuts] GPS disciplined Mars clock

[Martin Burnicki]

Joe Fitzgerald schrieb:
> 
> What organization is in charge of inserting leap seconds into the
> Martian time scale?

IMRS - International Mars Rotation Service ;-)


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Re: [time-nuts] GPS disciplined Mars clock

[jimlux]

On 7/9/16 9:23 AM, Mark Sims wrote:

Do you have any equations for calculating Jovian (or Pluto) time and date from 
UTC / GPS / TAI time?   Lady Heather does not want to slight any of our other 
potential planetary overlords (but could whip their bloated gaseous asses in a 
fight)



I'm sure JPL Horizons or a similar site has Spice Kernels which 
encapsulate such information.


Jupiter has a 10 hour day, which should make things exciting

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Re: [time-nuts] GPS disciplined Mars clock

[jimlux]

On 7/9/16 10:24 AM, Joe Fitzgerald wrote:


What organization is in charge of inserting leap seconds into the
Martian time scale?

Inasmuch as there's no business concerns about noon being local solar 
noon, probably nobody..


TAI my friend, TAI...



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Re: [time-nuts] GPS disciplined Mars clock

[Richard W. Solomon]

United Federation of Planets.

Dick, W1KSZ

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Joe Fitzgerald
Sent: Saturday, July 09, 2016 10:24 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPS disciplined Mars clock


What organization is in charge of inserting leap seconds into the Martian time 
scale?

-Joe Fitzgerald KM1P

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Re: [time-nuts] GPS disciplined Mars clock

[Joe Fitzgerald]

What organization is in charge of inserting leap seconds into the
Martian time scale?

-Joe Fitzgerald KM1P

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Re: [time-nuts] GPS disciplined Mars clock

[Bob Camp]

Hi

You haven’t even scratched the surface yet …. What time is it on each 
of the moons? :)

Bob

> On Jul 9, 2016, at 12:36 PM, Mike Cook  wrote:
> 
> Calculating the local planetary time is fine for solid objects with an 
> accepted (or proposed) prime meridian , but I don’t think this is possible 
> with gaseous objects where there is no fixed feature. 
> 
>> Le 9 juil. 2016 à 18:23, Mark Sims  a écrit :
>> 
>> Do you have any equations for calculating Jovian (or Pluto) time and date 
>> from UTC / GPS / TAI time?   Lady Heather does not want to slight any of our 
>> other potential planetary overlords (but could whip their bloated gaseous 
>> asses in a fight)
>> 
>>
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> 
> "The power of accurate observation is commonly called cynicism by those who 
> have not got it. »
> George Bernard Shaw
> 
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Re: [time-nuts] GPS disciplined Mars clock

[Nick Sayer via time-nuts]

I’ve often wondered how much sense it makes to speak of the rotational period 
of a gaseous planet. The different layers of the atmosphere potentially can 
have different rotational periods, and we can’t observe the actually rocky (or 
diamond, if you believe Arthur C. Clark) body at the center.

I looked into writing firmware for the Crazy Clock for the other planets 
besides Mars. Mercury and Venus have extraordinarily long day lengths, so the 
math doesn’t work out, and the remaining planets are gaseous.

> On Jul 9, 2016, at 9:23 AM, Mark Sims  wrote:
> 
> Do you have any equations for calculating Jovian (or Pluto) time and date 
> from UTC / GPS / TAI time?   Lady Heather does not want to slight any of our 
> other potential planetary overlords (but could whip their bloated gaseous 
> asses in a fight)
> 
> 
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Re: [time-nuts] GPS disciplined Mars clock

[Mike Cook]

> Le 9 juil. 2016 à 17:33, Scott McGrath  a écrit :
> 
> The Venusian's are feeling left out ….

I guess it is possible as there is an agreed prime meridian even though we 
cannot see the central peak in the crater Ariadne in the visible spectrum.

> 
> Content by Scott
> Typos by Siri
> 
>> On Jul 9, 2016, at 2:58 AM, Mark Sims  wrote:
>> 
>> To appease our new (hopefully) benevolent Martian overlords,  Lady Heather 
>> can now work in Mars time...   and I have it running right now while 
>> connected to a Jupiter timing receiver.
>> 
>> -
>>> Hmm. I have a SC-01.. One could hook it up to a Arduino trivially.
>> And run it on Mars time.. 
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"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] GPS disciplined Mars clock

[Mike Cook]

Calculating the local planetary time is fine for solid objects with an accepted 
(or proposed) prime meridian , but I don’t think this is possible with gaseous 
objects where there is no fixed feature. 

> Le 9 juil. 2016 à 18:23, Mark Sims  a écrit :
> 
> Do you have any equations for calculating Jovian (or Pluto) time and date 
> from UTC / GPS / TAI time?   Lady Heather does not want to slight any of our 
> other potential planetary overlords (but could whip their bloated gaseous 
> asses in a fight)
> 
> 
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"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] GPS disciplined Mars clock

[Scott McGrath]

The Venusian's are feeling left out 

Content by Scott
Typos by Siri

> On Jul 9, 2016, at 2:58 AM, Mark Sims  wrote:
> 
> To appease our new (hopefully) benevolent Martian overlords,  Lady Heather 
> can now work in Mars time...   and I have it running right now while 
> connected to a Jupiter timing receiver.
> 
> -
>> Hmm. I have a SC-01.. One could hook it up to a Arduino trivially.
> And run it on Mars time.. 
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[time-nuts] GPS disciplined Mars clock

[Mark Sims]

Do you have any equations for calculating Jovian (or Pluto) time and date from 
UTC / GPS / TAI time?   Lady Heather does not want to slight any of our other 
potential planetary overlords (but could whip their bloated gaseous asses in a 
fight)

  
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[time-nuts] Info about 74hct4046 and 74hct9046

[Daniel Mendes]

Hi, I opened a case with NXP to find application note "9397 750 00078" 
about these chips. They sent me it together with some spreadsheets and a 
design program. The spreadheets were for Lotus123 and the program for DOS :D


I converted them to xlsx and made a VM running FreeDOS with the design 
program.


Oz, from DFW (Texas, USA), kindly hosted all the files (original and 
modified) in his website:


http://ozindfw.net/TimeNuttery/Mendes_Daniel/

Enjoy.


Daniel

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Re: [time-nuts] GPS disciplined Mars clock

[jimlux]

On 7/8/16 11:58 PM, Mark Sims wrote:

To appease our new (hopefully) benevolent Martian overlords,  Lady Heather can 
now work in Mars time...   and I have it running right now while connected to a 
Jupiter timing receiver.




Now that Juno is getting ready to peer beneath Jupiter's clouds 
(there's a really great poster, probably a one-off, with an image of 
Jupiter and a zipper), maybe we should be worrying about our Jovian 
overlords.


Juno doesn't carry a USO, but it does have coherent turnaround 
transponders for X and Ka band which have pretty good Allan Deviation 
performance:  less than 1E-15 added deviation over 1000 seconds.




-

Hmm. I have a SC-01.. One could hook it up to a Arduino trivially.

And run it on Mars time..   
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Re: [time-nuts] The home time-lab

[Alexander Pummer]

if yo limit the Q you limit the effect also... by the way the Q is 
already limited by the ohmic resistance of your transformer coils.


73
KJ6UHN
Alex

On 7/8/2016 10:08 PM, David wrote:

And I will add a high voltage power resistor to limit the Q.

On Fri, 8 Jul 2016 22:12:53 -0400, you wrote:


Hi

If you try this, be very careful with the voltage at the junction of the L and 
the C.

Bob


On Jul 8, 2016, at 9:52 PM, David  wrote:

I wonder how well a pair of high voltage transformers wired back to
back with a 60 Hz series resonate LC circuit between them would work
for removing power line glitches.  They wouldn't do anything for
voltage regulation unlike a constant voltage transformer though.  Time
to break out a couple of plate transformers and try it I guess.

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-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7640 / Virus Database: 4613/12583 - Release Date: 07/08/16


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Re: [time-nuts] The home time-lab

[Bob Camp]

Hi

Yes indeed they do run a bit warm. You need a mounting location that gets them 
out 
of the way. Having them somewhere you can bump into them …. not good at all. The
newer “toroid” designs are a bit quieter than the older versions. 

Bob


> On Jul 9, 2016, at 2:41 AM, Rob Sherwood.  wrote:
> 
> The minor down side is these resonant transformers acoustically hum and run 
> hot.  On the plus side they do clean up any kind of noise on the line.  
> Rob, NC0B
> 
> Sent from my iPad
> 
>> On Jul 8, 2016, at 1:52 PM, Brooke Clarke  wrote:
>> 
>> 
>> 
>> Hi Bob:
>> 
>> A resonate transformer may solve your problem.  I added one to my first 
>> computer, See Fig 1.
>> http://www.prc68.com/I/comp.shtml#SWTP
>> http://www.prc68.com/I/Images/SWTP-01b.jpg
>> The oval shaped silver can oil capacitor is connected to a winding on the 
>> transformer and resonates at 60 Hz.  Think of it as a filter centered at 60 
>> Hz and as an energy storage device.
>> This removes line spikes and fills in narrow line drop outs.
>> https://en.wikipedia.org/wiki/Voltage_regulator#Constant-voltage_transformer
>> 
>> Here are models with capacities of: 300, 600, 1200 & 1800 VA:
>> http://www.hammondmfg.com/CVR.htm
>> Just search for "Constant-voltage transformer".
>> 
>> -- 
>> Have Fun,
>> 
>> Brooke Clarke
>> http://www.PRC68.com
>> http://www.end2partygovernment.com/2012Issues.html
>> The lesser of evils is still evil.
>> 
>>  Original Message 
>>> I hope this isn't too far off topic, as this is having a big impact on my 
>>> testing.
>>> 
>>> I decided to run an A/B test on one of my GPSDOs: comparing the phase of 
>>> the two 10MHz output channels.  In the middle of the night, there was a 
>>> long series of 35ns pops in the phase data.  Strangely enough, there was 
>>> nothing in the data collected directly from the unit involved.  The 
>>> preceding two days we had had a number of switching transients where the 
>>> lights blinked but nothing shut down.  So, putting one and one together, I 
>>> suspect that a fair percentage of the strange results I've been getting has 
>>> been power-grid related.
>>> So, what to do?  I've been looking at UPS devices, and I don't even 
>>> understand enough to waste my money on a bad one.  The two big questions 
>>> seem to be "on-line" and "sine wave".  Make that three: can I trust the 
>>> mfgs claims?  Is there something affordable that could run a pair of 5370s 
>>> and maybe another 50W worth of DUTs for up to an hour or two and not be 
>>> prey to power-line transients?  Or would it be more cost effective to 
>>> somehow monitor the power line for spikes or phase jumps and blow off tests 
>>> or cut out the offending data?  From time to time we get a thread on 
>>> power-line nuts.  Should I have been paying more attention?
>>> 
>>> Bob - AE6RV
>>> ---
>>> GFS GPSDO list:
>>> groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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Re: [time-nuts] The home time-lab

[Rob Sherwood .]

The minor down side is these resonant transformers acoustically hum and run 
hot.  On the plus side they do clean up any kind of noise on the line.  
Rob, NC0B

Sent from my iPad

> On Jul 8, 2016, at 1:52 PM, Brooke Clarke  wrote:
> 
> 
> 
> Hi Bob:
> 
> A resonate transformer may solve your problem.  I added one to my first 
> computer, See Fig 1.
> http://www.prc68.com/I/comp.shtml#SWTP
> http://www.prc68.com/I/Images/SWTP-01b.jpg
> The oval shaped silver can oil capacitor is connected to a winding on the 
> transformer and resonates at 60 Hz.  Think of it as a filter centered at 60 
> Hz and as an energy storage device.
> This removes line spikes and fills in narrow line drop outs.
> https://en.wikipedia.org/wiki/Voltage_regulator#Constant-voltage_transformer
> 
> Here are models with capacities of: 300, 600, 1200 & 1800 VA:
> http://www.hammondmfg.com/CVR.htm
> Just search for "Constant-voltage transformer".
> 
> -- 
> Have Fun,
> 
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
> The lesser of evils is still evil.
> 
>  Original Message 
>> I hope this isn't too far off topic, as this is having a big impact on my 
>> testing.
>> 
>> I decided to run an A/B test on one of my GPSDOs: comparing the phase of the 
>> two 10MHz output channels.  In the middle of the night, there was a long 
>> series of 35ns pops in the phase data.  Strangely enough, there was nothing 
>> in the data collected directly from the unit involved.  The preceding two 
>> days we had had a number of switching transients where the lights blinked 
>> but nothing shut down.  So, putting one and one together, I suspect that a 
>> fair percentage of the strange results I've been getting has been power-grid 
>> related.
>> So, what to do?  I've been looking at UPS devices, and I don't even 
>> understand enough to waste my money on a bad one.  The two big questions 
>> seem to be "on-line" and "sine wave".  Make that three: can I trust the mfgs 
>> claims?  Is there something affordable that could run a pair of 5370s and 
>> maybe another 50W worth of DUTs for up to an hour or two and not be prey to 
>> power-line transients?  Or would it be more cost effective to somehow 
>> monitor the power line for spikes or phase jumps and blow off tests or cut 
>> out the offending data?  From time to time we get a thread on power-line 
>> nuts.  Should I have been paying more attention?
>> 
>> Bob - AE6RV
>>  
>> ---
>> GFS GPSDO list:
>> groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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[time-nuts] GPS disciplined Mars clock

[Mark Sims]

To appease our new (hopefully) benevolent Martian overlords,  Lady Heather can 
now work in Mars time...   and I have it running right now while connected to a 
Jupiter timing receiver.

-
> Hmm. I have a SC-01.. One could hook it up to a Arduino trivially.
And run it on Mars time.. 
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