Re: [time-nuts] Dual GPSDO - any advantage?

[ewkehren via time-nuts]

We use Excell nice to make plots and when needed add calculations File is to 
large for time nuts contact me direct and I will send you an exampleBert Kehren


Sent from my Galaxy Tab® A
 Original message From: CORNACCHIA via time-nuts 
<time-nuts@febo.com> Date: 4/10/18  2:35 PM  (GMT-05:00) To: ewkehren via 
time-nuts <time-nuts@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any 
advantage? 
 Bert may I ask how you created the charts (what software are you using).Thank 
You
    On Tuesday, April 10, 2018, 9:04:58 a.m. EDT, ewkehren via time-nuts 
<time-nuts@febo.com> wrote:  
 
 Looking at the pictures it is the same unit I bought. It is not dual oven bit 
trimble works with LH right now shows tracking 10 satelites.Attached  is data 
that made  me buy a second one for Jürg for $ 129  and one more for me for 
$9.50.What you see is highly filtered data to see long time changes to better 
understand if analog filtering os possible. Planning on using Wenzel 600 sec. 
Filter maybe up to 2000 seconds. Board is ready for order.Top plot is my data 
against my Cs 5061B bottom is original Tbolt against his FTS  Cs. We use 53132 
counters.I think  the new one lends it self better for filtering looking at 
both  with my Tracor, Trimble uses a  much shorter time constant and no short 
1E-10 changes you see on our standard units.Will keep you posted         Bert 
Kehren

Sent from my Galaxy Tab® A
 Original message From: Tim Shoppa <tsho...@gmail.com> Date: 
4/10/18  6:46 AM  (GMT-05:00) To: Discussion of precise time and frequency 
measurement <time-nuts@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any 
advantage? 
Most of the Chinese cheapo units have been frequency, not phase locked.

It would be great if you could put the GPSDO outputs into a 2 Channel scope and 
eyeball them for a while to see if they appear in phase (say plus-minus 20ns) 
over a few hours.

Tim N3QE

> On Apr 10, 2018, at 1:43 AM, donald collie <donaldbcol...@gmail.com> wrote:
> 
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your commentsDonald
> Brett Collie ZL4GX
> 
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
> ___
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Re: [time-nuts] Dual GPSDO - any advantage?

[ewkehren via time-nuts]

Jürg will have to explain he is in Switzerland  will be tomorrowBert


Sent from my Galaxy Tab® A
 Original message From: CORNACCHIA via time-nuts 
<time-nuts@febo.com> Date: 4/10/18  2:35 PM  (GMT-05:00) To: ewkehren via 
time-nuts <time-nuts@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any 
advantage? 
 Bert may I ask how you created the charts (what software are you using).Thank 
You
    On Tuesday, April 10, 2018, 9:04:58 a.m. EDT, ewkehren via time-nuts 
<time-nuts@febo.com> wrote:  
 
 Looking at the pictures it is the same unit I bought. It is not dual oven bit 
trimble works with LH right now shows tracking 10 satelites.Attached  is data 
that made  me buy a second one for Jürg for $ 129  and one more for me for 
$9.50.What you see is highly filtered data to see long time changes to better 
understand if analog filtering os possible. Planning on using Wenzel 600 sec. 
Filter maybe up to 2000 seconds. Board is ready for order.Top plot is my data 
against my Cs 5061B bottom is original Tbolt against his FTS  Cs. We use 53132 
counters.I think  the new one lends it self better for filtering looking at 
both  with my Tracor, Trimble uses a  much shorter time constant and no short 
1E-10 changes you see on our standard units.Will keep you posted         Bert 
Kehren

Sent from my Galaxy Tab® A
 Original message From: Tim Shoppa <tsho...@gmail.com> Date: 
4/10/18  6:46 AM  (GMT-05:00) To: Discussion of precise time and frequency 
measurement <time-nuts@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any 
advantage? 
Most of the Chinese cheapo units have been frequency, not phase locked.

It would be great if you could put the GPSDO outputs into a 2 Channel scope and 
eyeball them for a while to see if they appear in phase (say plus-minus 20ns) 
over a few hours.

Tim N3QE

> On Apr 10, 2018, at 1:43 AM, donald collie <donaldbcol...@gmail.com> wrote:
> 
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your commentsDonald
> Brett Collie ZL4GX
> 
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
> ___
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Re: [time-nuts] Dual GPSDO - any advantage?

[ewkehren via time-nuts]

Most likely but PayPal will have to get involved since there are more than one 
of usBert Kehren


Sent from my Galaxy Tab® A
 Original message From: Clint Jay  Date: 
4/10/18  10:32 AM  (GMT-05:00) To: Discussion of precise time and frequency 
measurement  Subject: Re: [time-nuts] Dual GPSDO - any 
advantage? 
Ahh, I've found the listing, has anyone received one?

I hate to say this but I'm highly sceptical that they will ever turn up,
looks and smells very much like the standard eBay scam to me.





On 10 April 2018 at 14:52, Bob kb8tq  wrote:

> Hi
>
> Simple answer is that the “simple” approaches don’t do much to improve
> things.
> Errors are indeed un-correlated, even off of the same antenna. You *could*
> average the result off of the two. That might improve things by sqrt(2). My
> experience is that the bumps and lumps (when they do occur) are not the
> sort
> of thing that averages out nicely…..
>
> Bob
>
> > On Apr 10, 2018, at 1:43 AM, donald collie 
> wrote:
> >
> > I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> > error!] They are stated as being new, and use a Trimball dual oven OCXO.
> I
> > plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s]
> It`s
> > been said that a man with two watches is never happy - unless, of course,
> > they agree with each other ;-). Being identical the outputs should be
> > coherent, unless one becomes faulty [one advantage of having two - any
> > discrepancy and you know something must be wrong]], but is there some
> > crafty way I can squeeze a little more "accuracy" out of two than if I
> only
> > used one?
> > TIA for your commentsDonald
> > Brett Collie ZL4GX
> >
> > PS : I have no connection to the eBay seller. The US$9-50 seems to
> include
> > a basic puck antenna, long downlead, and 4 interseries adaptors
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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>



-- 
Clint. M0UAW IO83

*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
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Re: [time-nuts] Dual GPSDO - any advantage?

[ewkehren via time-nuts]

I have run 2 Tbolts from thee same antenna  in to my Tracor and see the 
corrections are in no way correlated.Bert Kehren


Sent from my Galaxy Tab® A
 Original message From: Florian Teply  Date: 
4/10/18  7:00 AM  (GMT-05:00) To: time-nuts@febo.com Subject: Re: [time-nuts] 
Dual GPSDO - any advantage? 
Am Tue, 10 Apr 2018 17:43:25 +1200
schrieb donald collie :

> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven
> OCXO. I plan to run these in parallel [2 antennas, 2 feedlines, and 2
> GPSDO`s] It`s been said that a man with two watches is never happy -
> unless, of course, they agree with each other ;-). Being identical
> the outputs should be coherent, unless one becomes faulty [one
> advantage of having two - any discrepancy and you know something must
> be wrong]], but is there some crafty way I can squeeze a little more
> "accuracy" out of two than if I only used one?
> TIA for your
> commentsDonald Brett
> Collie ZL4GX

well, my experience in that regard is very limited, not to say
nonexisting, thus take the following with a grain of salt.

Assuming a system with two antenna locations where one device would
be fed both antennas, one could potentially employ some extra
correction based on extra knowledge from these two antennas. Even
though the antenna location usually is known with limited accuracy
(error on the order of 1m), the relative location of two antennas can
be known to a much greater accurracy (order of centimetres or better).
If the system can take that extra information into account, one could
maybe gain some extra accuracy for the solution of time/location.
For example, if the antennas are mounted 1m apart, and everything else
being equal, it is a priori clear, that the calculated position for
both antennas should also be 1m apart. As the signal received by both
antennas should be correlated, while their respective noise
contribution is not, one should gain some SNR. If on top of that time
resolution of the receiver system is very high, one could even take the
phase shift between signals received from both signals into account
similar to the way beam steering is done with phased antenna arrays,
just on receive side, again improving SNR. 
So far for an integrated system, where all signals arew processed in
one place. Now, as I read it you'll rather have two entirely separate
receiver systems. Here, depending on how it is implemented in the
receivers, one could potentially  still gain something extra over a
single unit, but I'd bet this can only be done in postprocessing.
After all, receiver A has no access to the signals as received by
receiver B and vice versa, therefore the spatial relationship can not
be used while deriving the timing solution. Maybe the independent
position solutions could be used to correct the timing solutions after
the fact.

Best regards,
Florian
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Re: [time-nuts] Dual GPSDO - any advantage?

[ewkehren via time-nuts]

Looking at the pictures it is the same unit I bought. It is not dual oven bit 
trimble works with LH right now shows tracking 10 satelites.Attached  is data 
that made  me buy a second one for Jürg for $ 129  and one more for me for 
$9.50.What you see is highly filtered data to see long time changes to better 
understand if analog filtering os possible. Planning on using Wenzel 600 sec. 
Filter maybe up to 2000 seconds. Board is ready for order.Top plot is my data 
against my Cs 5061B bottom is original Tbolt against his FTS  Cs. We use 53132 
counters.I think  the new one lends it self better for filtering looking at 
both  with my Tracor, Trimble uses a  much shorter time constant and no short 
1E-10 changes you see on our standard units.Will keep you posted         Bert 
Kehren

Sent from my Galaxy Tab® A
 Original message From: Tim Shoppa  Date: 
4/10/18  6:46 AM  (GMT-05:00) To: Discussion of precise time and frequency 
measurement  Subject: Re: [time-nuts] Dual GPSDO - any 
advantage? 
Most of the Chinese cheapo units have been frequency, not phase locked.

It would be great if you could put the GPSDO outputs into a 2 Channel scope and 
eyeball them for a while to see if they appear in phase (say plus-minus 20ns) 
over a few hours.

Tim N3QE

> On Apr 10, 2018, at 1:43 AM, donald collie  wrote:
> 
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your commentsDonald
> Brett Collie ZL4GX
> 
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
> ___
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Filter 500 Tb + Tb2.pdf
Description: Adobe PDF document
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Re: [time-nuts] Dual GPSDO - any advantage?

[ewkehren via time-nuts]

I bought one too, is a mistake, I am holding my breath  supposedly shipped I 
previously bought two one for Jürg because it's performance, easier to clean up 
            Bert Kehren


Sent from my Galaxy Tab® A
 Original message From: donald collie  
Date: 4/10/18  1:43 AM  (GMT-05:00) To: Discussion of precise time and 
frequency measurement  Subject: [time-nuts] Dual GPSDO - 
any advantage? 
I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
error!] They are stated as being new, and use a Trimball dual oven OCXO. I
plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
been said that a man with two watches is never happy - unless, of course,
they agree with each other ;-). Being identical the outputs should be
coherent, unless one becomes faulty [one advantage of having two - any
discrepancy and you know something must be wrong]], but is there some
crafty way I can squeeze a little more "accuracy" out of two than if I only
used one?
TIA for your commentsDonald
Brett Collie ZL4GX

PS : I have no connection to the eBay seller. The US$9-50 seems to include
a basic puck antenna, long downlead, and 4 interseries adaptors
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Re: [time-nuts] Recommendations for Mains Power Monitor / Logger

[ewkehren via time-nuts]

My 20 year old Junghans`s had no problemBert Kehren Palm City Florida


Sent from my Galaxy Tab® A
 Original message From: Tom Van Baak  
Date: 3/11/18  8:32 AM  (GMT-05:00) To: Discussion of precise time and 
frequency measurement  Subject: Re: [time-nuts] 
Recommendations for Mains Power Monitor / Logger 
Bob,

Correct, measuring mains frequency to a couple of digits is not hard. What 
makes an interesting challenge is to monitor mains, "kitchen clock", phase 
drift. And to do it with cycle accuracy; no slips. Note that to measure down to 
1 cycle over 1 day is 0.2 ppm. Over a month, 6 ppb, and over a year, 5e-10. So 
the numbers add up and you see why we use atomic standards or GPS or even NTP 
as a long-term reference for this.

Your measurement system needs to have short- and long-term stability ~10x 
better than:
    http://leapsecond.com/pic/mains-adev-mdev-gnuplot-g4.png

Again, that's not asking a lot. But it makes a really fun project. Much of what 
you ever need to know about time & frequency metrology can be done by a student 
with $10 in parts and a 60 Hz outlet.

/tvb

p.s. Yes, it's very early here on the west coast, but I had to check how badly 
my WWVB clocks handled DST a few hours ago.

- Original Message - 
From: "Bob kb8tq" 
To: "Discussion of precise time and frequency measurement" 
Sent: Sunday, March 11, 2018 4:53 AM
Subject: Re: [time-nuts] Recommendations for Mains Power Monitor / Logger


Hi

So, how good is “good enough?”. My first attempt ran a counter with a 1 us 
period resolution. 
(remember, it was tube based …). That turned out to be major overkill in terms 
of line frequency
measurement. 60.123 Hz is doing pretty well in terms of line frequency. Even to 
get that level, you 
will be doing a bit of filtering (or you are  just watching the last two digits 
pop around randomly). 

Your typical time base in a PC is good to a few hundred ppm. That’s giving you 
an error in the 
fourth digit of your measurement. With a bit of luck, your sound card timebase 
may be 5X 
more accurate than your system clock. (or it may be worse …) it depends a bit 
on how fancy
your audio setup is. 

Adding NTP to your PC will correct for any long term errors. In a rational 
environment it should 
get you into the “few ppm” range short term and zero error long term. 

A GPS gizmo will get you into the parts per billion (or better) range. It might 
be 100’s of ppb, but it’s
still *way* better than your CPU clock. The usual auction sites have lots of 
candidates in the sub $50
range.There are also places that are happy to sell you shields with GPS devices 
on them.

A fancier yet solution is a GPSDO. We are well into overkill at this point. The 
advantage to using
one is that it may be the time / frequency standard for your entire lab setup. 
You are up in the 
$100 to $500 range for most of them. They will get you into 10’s or 100’s of 
parts per trillion. 

There are indeed *lots* of different time sources you could use. The number of 
alternatives is 
*much* larger than what’s on the list above.

Bob

> On Mar 10, 2018, at 11:46 PM, Tom Van Baak  wrote:
> 
>> I've done some Googling and have found any number of designs.
> 
> Pat,
> 
> 1) Safety. I usually use a low voltage step-down transformer. This gives 
> isolation and safety. Anything from 3 VAC to 24 VAC is fine.
> 
> 2) Trigger. There are dozens of schematics on the web for capturing the 
> zero-crossing of a low-voltage sine wave. You can easily go overboard on 
> this. Or just keep it simple and feed the signal through a resistor directly 
> into a microprocessor input. The internal clamping diodes do their thing. A 
> Schmitt trigger input is helpful but not necessary depending on how your 
> software makes the measurement.
> 
> 3) Timebase. Given the long-term accuracy of mains (seconds a day, seconds a 
> year) you don't need an atomic timebase. If you collect data for a couple of 
> days any old XO will be fine. If you plan to collect data for months you may 
> want a OCXO. Most of us just use cheap GPS receivers.
> 
> 4) Measurement. There are many ways to measure the signal. You can measure 
> frequency directly, as with a frequency counter. You get nice data but it may 
> not be perfect long-term due to dead time or gating effects in the counter.
> 
> So what most of us do is measure phase (time error) instead. One way is to 
> make time interval measurements from a given mains cycle to a GPS 1PPS tick 
> or vice versa, from each GPS/1PPS tick to the very next mains cycle. Either 
> way you get about sample per second. If you're in search of perfection it 
> gets a bit tricky when the two signals are in a coincidence zone.
> 
> The other approach is not to use a frequency or time interval counter at all. 
> Instead you timestamp each cycle, or every 60th cycle. Unix-like systems have 
> this capability. See 

Re: [time-nuts] LT1016 as a pulse shaper...

[ewkehren via time-nuts]

BruceWisjh I had known about it a week ago and we could have added a board to 
the A9 order. Next order is probably three weeks away ifIi can help contact me 
off list     Bert Kehren
Sent from my Galaxy Tab® A
 Original message From: Bruce Griffiths 
 Date: 3/4/18  8:32 PM  (GMT-05:00) To: Hal Murray 
, Discussion of precise time and frequency measurement 
 Subject: Re: [time-nuts] LT1016 as a pulse shaper... 
Since I have a Timepod all that I'd need would be a board that had SMA inputs 
and outputs with provision for an LC L network to  step up the input if 
necessary plus an RLC network on the output something like in the attachment.

If one doesnt have a Timepod or equivalent a low noise phase detector will 
suffice for the noisier sources. An adjustable phase shift network is required 
to achieve quadrature between the LO (driven directly from the splitter) and 
the RF input (driven by the DUT output).

The required phase shift adjustment range could perhaps be reduced by using a 
quadrature hybrid to split the test source instead of a standard splitter. The 
output of the phase detector is low pass filtered and amplified and fed to a 
high resolution ADC such as a sound card.

Bruce

> 
> On 05 March 2018 at 13:59 Hal Murray  wrote:
> 
> Bruce Griffiths  said:
> 
> > > 
> > If I had a suitable PCB board for it I would do the measurement 
> >properly.
> > 
> > > 
> What would a suitable board look like and/or what sort of gear do you 
>need to
> measure PN?
> 
> --
> These are my opinions. I hate spam.
> 
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Re: [time-nuts] LT1016 as a pulse shaper...

[ewkehren via time-nuts]

We only use three circuits Wenzel sn65ELT35 and LTC6957. For critical 
applications it is the LTC we refer to it in our designs the Bruce circuit the 
only problem is solderability, my eyes. Bought 25, to poor to buy junk and not 
smart  enough to select something less in critical applications.        Bert 
Kehren


Sent from my Galaxy Tab® A
 Original message From: Bruce Griffiths 
 Date: 3/3/18  4:56 PM  (GMT-05:00) To: "David C. 
Partridge" , Discussion of precise time and 
frequency measurement , Ulf Kylenfall  
Subject: Re: [time-nuts] LT1016 as a pulse shaper... 
Hystersis (exhibited by 74xx14 devices) results in AM to PM conversion which 
increases as the amount of hysteresis increases.


Bruce

> 
> On 04 March 2018 at 10:34 Bruce Griffiths  
>wrote:
> 
> Ideally one should use a Collins style optimised cascade of increasing 
>bandwidth and gain limiting stages. The LTC6957 with its selectable input 
>stage bandwidth has a performance that is comparable with the Holzworth sine 
>to CMOS "amplifier" which is better than any comparator by itself. If the 
>amplitude of the input signal is large enough (i.e. input slew rate seen by 
>the gate is large enough) the performance of a single CMOS gate can be very 
>good. However the performance of current CMOS gates degrades in this 
>application with input frequencies of 100MHz and above.
> 
> Measuring the PN performance of CMOS gates used as sine to CMOS 
>converters is on the todo list.
> 
> Bruce
> 
> > > 
> > On 04 March 2018 at 06:38 "David C. Partridge" 
> > wrote:
> > 
> > You might consider using MC74VHC1GT14 or MC74VHC1G14 (Schmitt 
> >trigger inverting buffers) depending on the exact voltage levels.
> > 
> > They are fast (74AC logic fast) single gate devices in SC70 
> >(SOT-353) or SOT23-5 case and can drive 25mA output if needed.
> > 
> > I've seen documents saying that using fast logic gates can result 
> >in lower jitter/phase noise. Bruce - do you know ?
> > 
> > David
> > 
> > -Original Message-
> > From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of 
> >Ulf Kylenfall via time-nuts
> > Sent: 03 March 2018 17:08
> > To: Discussion of Precise Time and Frequency Measurement
> > Subject: [time-nuts] LT1016 as a pulse shaper...
> > 
> > Gentlemen,
> > I have so far been using LT1016 as a pulse shaper and also whenever 
> >I needed toconvert a sine wave into TTL Logic levels. Some hysteresis and 
> >all the decouplingand layout precautions as recommended by LT.
> > Are there any similar or better alternatives out there that could 
> >be usedthat would provide lower jitter and that are less expenceive?
> > Ulf Kylenfall
> > SM6GXV
> > 
> > ___
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> >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> > 
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Re: [time-nuts] Microsemi up for sale?

[ewkehren via time-nuts]

The manager many not know but the market does and there have been announcements 
and the stock is up and for the day the fifth most active of all US markets. At 
2 pm #2    Bert Kehren


Sent from my Galaxy Tab® A
 Original message From: "Richard (Rick) Karlquist" 
 Date: 3/3/18  9:30 AM  (GMT-05:00) To: Discussion of 
precise time and frequency measurement , Anders Wallin 
 Subject: Re: [time-nuts] Microsemi up for sale? 
I asked the CBT manager at Microsemi about this
rumor and he disavowed any knowledge of this.
He told me they were making 8 a week (not clear
if this is just 5071A's, or includes replacement
CBT's).  I don't remember the production ever
being anywhere near this level.  The reason
for the relatively brisk sales is that the risk
of GPS spoofing means that various military and
3 letter agencies need to own dedicated 5071's.
With a large installed base of 5071's, there will
be a guaranteed market for replacement tubes.
The US government considers the 5071A to be of
great strategic importance and would be certain
to "encourage" its continued production in case
of any business reorganization.

When we designed the 5071A twenty five years ago,
it seemed that there were two safe bets:

1.  Working Cs standards (outside the lab) would
obsoleted by what HP called "smart clocks" running
off of GPS.

2.  Magnetic state selection, as used in the 5071A,
would be replaced by optical pumping.  Len Cutler
was heartbroken that HP/Agilent management wouldn't
fund this effort.

It turns out that, even now in 2018, optical pumping
is not ready for prime time in a working standard
because the lasers drift over time.  The 5071A's
claim to fame is that you turn it on and it just
works ... until it runs out of cesium.  That is
another reason the 5071A isn't going away any time soon.

Rick Karlquist N6RK
Member: 5071A design team

On 3/3/2018 1:22 AM, Anders Wallin wrote:
> Just a change to the last part of the name then ;)
> https://www.ft.com/content/10192a2a-1d99-11e8-956a-43db76e69936
> "semi" -> "chip"
> 
> 
> On Sat, Jan 27, 2018 at 1:27 AM, Clint Jay  wrote:
> 
>> Perhaps of interest to the list
>>
>> https://www.theregister.co.uk/2018/01/25/microsemi/
>>
>> --
>> Clint.
>>
>> *No trees were harmed in the sending of this mail. However, a large number
>> of electrons were greatly inconvenienced.*
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[time-nuts] M12 furono

[ewkehren via time-nuts]

What is latest on a group buy, have I missed something I am ready to buy        
Bert Kehren



Sent from my Galaxy Tab® A
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Re: [time-nuts] FRK

[ewkehren via time-nuts]

PaulI have never seen a FRK or M 100 that did not have a screw iin lamp but 
Attila`s unit looks like nothing I have seen before,  I am not a Corby but over 
time 20 units have passed through my hands      
Bert


Sent from my Galaxy Tab® A
 Original message From: paul swed  Date: 
2/27/18  1:45 PM  (GMT-05:00) To: Discussion of precise time and frequency 
measurement  Subject: Re: [time-nuts] FRK 
Bert what I assume is the FRK lamp. it has a few wires and then 2 pins out
of the side.
Unless those are for mounting the lamp.
Regards
Paul
WB8TSL

On Tue, Feb 27, 2018 at 11:21 AM, Attila Kinali  wrote:

> On Tue, 27 Feb 2018 09:01:31 -0500
> Bob kb8tq  wrote:
>
> > Judging from the date codes on some of the parts, I’d guess that
> > your FRL-L is from 1982. I’m only looking at a few parts that came
> > through well enough in the picture to read (and that have what look
> > like rational date codes …).
>
> Sorry, I didn't take much care when taking the pictures.
> I can do better ones later.
>
> But yes, the board has definitely an 80s vibe. The whole construction
> is different then what I am used to from 80s electronics, though.
> But I guess that's because it was designed and manufactured for
> hi-rel applications.
>
> 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] FRK

[ewkehren via time-nuts]

Which one are you talking aboutBert Kehren


Sent from my Galaxy Tab® A
 Original message From: paul swed  Date: 
2/27/18  9:26 AM  (GMT-05:00) To: Discussion of precise time and frequency 
measurement  Subject: Re: [time-nuts] FRK 
Thanks for the pictures.
Curious on the rb lamp.
There seem to be 2 pins from the side. Is that a lamp start igniter?
Regards
Paul
WB8TSL

On Tue, Feb 27, 2018 at 9:01 AM, Bob kb8tq  wrote:

> Hi
>
> Judging from the date codes on some of the parts, I’d guess that
> your FRL-L is from 1982. I’m only looking at a few parts that came
> through well enough in the picture to read (and that have what look
> like rational date codes …).
>
> Bob
>
> > On Feb 27, 2018, at 5:30 AM, Attila Kinali  wrote:
> >
> > On Mon, 26 Feb 2018 20:04:56 -0800
> > "Tom Van Baak"  wrote:
> >
> >> Bert's M100 Rb teardown photos are now here:
> >>
> >> http://leapsecond.com/bert/m100.htm
> >
> > For those, who would like to see the rest of M100/FRK,
> > I just took pictures of my FRK-L that was sitting on my
> > desk for way too long:
> >
> > http://time.kinali.ch/Efratom_FRK-L/
> >
> > Yes, there are only the pictures of the four PCBs from outside.
> > I didn't want to take the FRK further appart, as that would
> > require a soldering iron, and I really should be doing something
> > else.
> >
> >   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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> mailman/listinfo/time-nuts
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>
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Re: [time-nuts] FRK

[ewkehren via time-nuts]

Thank you Attila, I have seen many FRK`and M 100 but not one like yours. Some 
boards are very different and it is very difficult  to get proper 
documentation.Bert Kehren

Sent from my Galaxy Tab® A
 Original message From: Attila Kinali  Date: 
2/27/18  5:30 AM  (GMT-05:00) To: Discussion of precise time and frequency 
measurement  Subject: Re: [time-nuts] FRK 
On Mon, 26 Feb 2018 20:04:56 -0800
"Tom Van Baak"  wrote:

> Bert's M100 Rb teardown photos are now here:
> 
> http://leapsecond.com/bert/m100.htm

For those, who would like to see the rest of M100/FRK,
I just took pictures of my FRK-L that was sitting on my
desk for way too long:

http://time.kinali.ch/Efratom_FRK-L/

Yes, there are only the pictures of the four PCBs from outside.
I didn't want to take the FRK further appart, as that would
require a soldering iron, and I really should be doing something
else.

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] Replacement A9 boards for the HP 5065A

[ewkehren via time-nuts]

We have decided to go with the 1012 do we need to do any thing with pin 5Bert 
kehren


Sent from my Galaxy Tab® A
 Original message From: Attila Kinali  Date: 
2/26/18  9:53 AM  (GMT-05:00) To: Discussion of precise time and frequency 
measurement  Subject: Re: [time-nuts] Replacement A9 boards 
for the HP 5065A 
On Sat, 24 Feb 2018 23:44:16 -0500
Charles Steinmetz  wrote:

> Given the relatively low resistances at the op-amp inputs (10k ohms), 
> the ultra-low input "bias" (leakage) current of the 6240 is simply 
> unnecessary.  Any offset due to the input currents (within the general 
> range of any of these op-amps) is insignificant compared to the op-amp's 
> offset voltage.  Thus, offset voltage, offset voltage tempco, and offset 
> voltage long-tem drift are the critical parameters (as Poul-Henning 
> pointed out).  And here, the 1012 is clearly the best of the three.  In 
> addition to having the lowest input offset spec, the 1012 has guaranteed 
> maximum specifications for these important parameters.  The 6240 (for 
> good reason) is *not even rated* for long-term stability (drift). 
> (Long-term offset stability is a particular weakness of CMOS op-amps.)

Oh.. right, I didn't think about long term behaviour. Thanks for the correction!

BTW: How about using an LTC2057 then? Its input bias current  and
GBW spec is similar to the LT1012, but its offset voltage and drift
are far superior. Or would its charge injection noise be too large
for this application?

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] FRK

[ewkehren via time-nuts]

Thank you I am presently only on my tablet I will be on my laptop in the 
morning do not think that there is much interest hardware or solder iron 1%Bert


Sent from my Galaxy Tab® A
 Original message From: Arnold Tibus <arnold.ti...@gmx.de> 
Date: 2/25/18  11:04 AM  (GMT-05:00) To: time-nuts@febo.com Subject: Re: 
[time-nuts] FRK 
Bert, you may upload it to this directory, which timenuts can then 
access and download as well, using this directory also:
https://my.hidrive.com/share/5fohndsi4k
The up- and downloads are much faster and there is no Mbit limit.
I will keep it open for a while. Give me a note if this ok for you.
Try it.
Of course, from time to time I will clean up a bit.

Regards,

Arnold, DK2WT

Am 25.02.2018 um 15:05 schrieb ewkehren via time-nuts:
> We have pictures of the guts of a M100 the file is 1.8 M off list or 
> permission to postBert Kehren
> 
> 
> Sent from my Galaxy Tab® A
> ___
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Re: [time-nuts] Replacement Backup Battery for 5065A?

[ewkehren via time-nuts]

Discooect I have seen them leak all over the placeBert Kehren 


Sent from my Galaxy Tab® A
 Original message From: Stan  Date: 
2/25/18  2:41 PM  (GMT-05:00) To: time-nuts@febo.com Subject: [time-nuts] 
Replacement Backup Battery for 5065A? 
With all this recent 5065A talk I decided to pull mine out of storage and fire 
it up. After a little time to let everything warm up and settle in, I'm happy 
to report that it's working just fine!

My 5065A has the battery backup option, and the battery is the original one 
(1420-0066, Energy Sales p/n ES710, 25.2V 1.4 Ah). Not surprisingly, the 
battery is quite dead. Does anyone any insight about installing a more modern 
battery (SLA or NiMH, perhaps) that will fit in the battery compartment in the 
5065A?

I've looked at a few small 12V/2.2Ah SLA batteries that are physically small 
enough that I should be able to fit a couple in the enclosure and connect them 
in series to get 24 volts out, but I want to wait until either I have assurance 
from someone with more experience than I that this will actually work, or a 
better idea about a more suitable replacement.

Thanks,
Stan

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[time-nuts] FRK

[ewkehren via time-nuts]

We have pictures of the guts of a M100 the file is 1.8 M off list or permission 
to postBert Kehren 


Sent from my Galaxy Tab® A
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Re: [time-nuts] Replacement A9 boards for the HP 5065A

[ewkehren via time-nuts]

Corby is still asleep, on the old board it was 0.5 uF and 100K now 5 uF and 
10K. Who knows what HP knew in the 60`s but it works and I dought that it is 
critical. No where is there any fine  tuning like two resistors in seriesBert 
Kehren 

Sent from my Galaxy Tab® A
 Original message From: Bill Hawkins  
Date: 2/24/18  10:26 PM  (GMT-05:00) To: 'Discussion of precise time and 
frequency measurement'  Subject: Re: [time-nuts] 
Replacement A9 boards for the HP 5065A 
Corby

A time constant is calculated from R and C.

If 50 milliseconds is the correct number, R for 5 mfd is 10,000 ohms.

You could use an aluminum electrolytic for the capacitor.

Can you tell us where the 50 ms number came from?

Regards,
Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of
cdel...@juno.com
Sent: Saturday, February 24, 2018 5:45 PM
To: time-nuts@febo.com
Subject: [time-nuts] Replacement A9 boards for the HP 5065A

Hi,

I'm working to make some replacement A9 boards for the HP 5065A to the
new style schematic.

Will share the Gerber file when done.

The integrator capacitor is a 1986 vintage TRW 5.0ufd 50V 10%
.42"DX1.0"L axial.

Of course it has an HP part number and no manufactures #.

Any guess as to what type it is?

Polycarbonate, polypropylene, ???

Just wanting to find a good modern replacement for its use. (Integrator
with a 50ms time constant.)

Thanks,

Corby

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Re: [time-nuts] "Super Rubidium" filter mod for PRS-10?

[ewkehren via time-nuts]

I still stand by FRK, next to HP largest cell, Corby did it with a M 100 much 
more difficult. I started on a FRK but because of a macular hole in my left eye 
had to stop.First  test  should be to change time constant and monitor 
performance.Remember the outstanding performance  of the HP is do to the fact 
that the optical unit takes over somewhere around 0.1 seconds.FRK is well 
documented and easy to work on.We have pictures have to compress to attach to 
time nuts or contact me off list.Again if some one wants to take over please 
contact me directBert Kehren 


Sent from my Galaxy Tab® A
 Original message From: Poul-Henning Kamp  
Date: 2/25/18  5:22 AM  (GMT-05:00) To: Discussion of precise time and 
frequency measurement , Stewart Cobb 
 Subject: Re: [time-nuts] "Super Rubidium" filter mod 
for PRS-10? 

In message 

Re: [time-nuts] Curious, how many t-nuts have 5065A

[ewkehren via time-nuts]

Old color and a little expensive only one partial pictureBert Kehren


Sent from my Galaxy Tab® A
 Original message From: Bob kb8tq  Date: 2/24/18 
 9:30 AM  (GMT-05:00) To: George Atkinson , 
Discussion of precise time and frequency measurement  
Subject: Re: [time-nuts] Curious, how many t-nuts have 5065A 
Hi

The “pickup only” part of the deal would be a bit of an issue for some of us :)

Bob

> On Feb 24, 2018, at 5:46 AM, George Atkinson via time-nuts 
>  wrote:
> 
> There is one on UK ebay at the moment but its not being given away. From the 
> one partial photograph it looks a bit rough.
> 
> https://www.ebay.co.uk/itm/HP-5065A-Rubidium-Frequency-Standard/183057846558?
> 
> Robert G8RPI.
> 
>> 
>>    On 24 February 2018 at 10:02 John Miles  wrote:
>> 
 
>>>    Hi
>>> 
>>>    Well, if anybody else is “giving away” 5065’s I’d certainly be 
>>>willing to
>>>    “accept”
>>>    one :)
>>> 
>>>    Bob
>>> 
 
>>    Be careful what you wish for. :) The unit Pete is talking about is a 
>>1969-era model, in nice overall shape but with the usual bad capacitors on 
>>the oven controller board. The lamp oven winding should be about 50 ohms 
>>cold, but is closer to a dead short. It will take a LOT of work to restore to 
>>working condition.
>> 
>>    The failed controller ran long enough to smoke a 1.5-ohm 1W resistor, 
>>1N400-something diode, and eventually the 1A line fuse ( 
>>http://www.ke5fx.com/5065A_A11_sm.jpg ). Needless to say the lamp PCB looks 
>>like something out of Fukushima. It'll need to be rebuilt from scratch after 
>>rewinding the heater.
>> 
>>    Seriously -- anyone with a 5065A who hasn't checked/replaced the caps on 
>>A11, don't let this happen to you. They aren't making any more of these 
>>puppies. If the caps on that board are original, don't bother to check them, 
>>just replace them, as Luciano suggests at 
>>http://www.timeok.it/hp5065a-corner-3/. No need for exotic parts, just put in 
>>whatever you have that is somewhere close to the original values.
>> 
>>    Not a bad idea to verify the ESR of the new parts you're installing as 
>>well.
>> 
>>    -- john, KE5FX
>>    Miles Design LLC
>> 
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[ewkehren via time-nuts]

Some  of you are to young to remember when Javanese products were considered 
junk same storyBert Kehren


Sent from my Galaxy Tab® A
 Original message From: "Van Horn, David" 
 Date: 2/22/18  4:44 PM  (GMT-05:00) To: 
Discussion of precise time and frequency measurement  
Subject: Re: [time-nuts] Teardown of Chinese made eBay GPS antenna. 
I wasn't making any comment about Chinese goods, just the component in question.

-Original Message-
From: time-nuts 
[mailto:time-nuts-bounces+david.vanhorn=backcountryaccess@febo.com] On 
Behalf Of William H. Fite
Sent: Thursday, February 22, 2018 2:40 PM
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

I wish people would lighten up on Chinese goods. Perhaps you are not aware that 
China builds for and sells to both the DOD and NASA. Chinese manufacturers 
build to the specs they are given. You want cheap crap, they'll build cheap 
crap. You want top quality, they'll build top quality.


On Thursday, February 22, 2018, Van Horn, David < 
david.vanh...@backcountryaccess.com> wrote:

> According to the data sheet, it looks pretty well in spec, and the 
> part has thermal shutdown.
> http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
>
> ESD hit maybe?
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--
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deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot for 
sinners. His standards are quite low.
--Desmond Tutu
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Re: [time-nuts] Curious, how many t-nuts have 5065A

[ewkehren via time-nuts]

Do not know but it is the holy grail of AV nuts short of a Maser  or 8607Bert 
Kehren


Sent from my Galaxy Tab® A
 Original message From: Pete Lancashire 
 Date: 2/22/18  9:44 AM  (GMT-05:00) To: Discussion of 
precise time and frequency measurement  Subject: 
[time-nuts] Curious, how many t-nuts have 5065A 
no reason other then  curious

-pete
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Re: [time-nuts] eBay GPS antenna.

[ewkehren via time-nuts]

Please keep us informed I bought onBert Kehren


Sent from my Galaxy Tab® A
 Original message From: John Green  Date: 
2/6/18  4:03 PM  (GMT-05:00) To: time-nuts@febo.com Subject: Re: [time-nuts] 
eBay GPS antenna. 
I kind of have to believe the specs. The two survey grade antennas I
already have, a Leica and a Trimble, both have regulators in the preamp
sections. The Leica has an 8 volt one and the Trimble has a 5 volt one. I
intend to hook it up to a variable supply and watch the current as I
increase voltage. If it has a regulator, the current should stabilize at an
input voltage just above what the internal preamp operates at. If not, it
should continue to rise. I am tempted to pry it apart, even if it risks
damage just so I can see for myself what they are using for the preamp
stages.
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Re: [time-nuts] Trimble Thunderbolt Issue

[ewkehren via time-nuts]

Do not toss, first check output of OCXO if good keep if you do not fiend the 
problem. If no output replace. If L H shows that it works bring OCXO output 
directly.Bert Kehren 


Sent from my Galaxy Tab® A
 Original message From: Richard Solomon  
Date: 1/26/18  1:39 PM  (GMT-05:00) To: time-nuts  Subject: 
[time-nuts] Trimble Thunderbolt Issue 
I have a T-Bolt whose 10 MHz output has dropped off to about 6 mV. Using T-Bolt 
Mon,

all the Alarms are Green and it shows Tracking 3 or 4 Satellites (small Hockey 
Puck Antenna).


Without a schematic I am lost as to where to look.


Anyone have any suggestions ? I had to toss an otherwise working T-Bolt.


Thanks for any assistance,


Dick, W1KSZ


Sent from Outlook
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Re: [time-nuts] Suggestion for a timing GPS receiver (Trimble / Ublox /other?)

[ewkehren via time-nuts]

The cheapest is not a 5T there are many 6 and 7 for $ 10. T gives you nothing 
unless you  have saw tooth correctionBerrt Kehren


Sent from my Galaxy Tab® A
 Original message From: Paride Legovini via time-nuts 
 Date: 1/23/18  12:24 PM  (GMT-05:00) To: 
time-nuts@febo.com Subject: Re: [time-nuts] Suggestion for a timing GPS 
receiver (Trimble /
  Ublox /other?) 
On 2018-01-23 08:11, David J Taylor via time-nuts wrote:
> Dear fellow nuts,
> 
> I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm
> looking for a good and possibly affordable timing GPS receiver.
> []
> Am I overlooking something or missing interesting options?
> 
> Cheers,
> 
> Paride IZ3SUS
> 
> 
> Paride,
> 
> As Mark notes, you don't need a timing precision GPS receiver for NTP
> 
> [...]
>
> Stephen mentioned the newer series-8 ublox modules.  These are indeed
> excellent (and can receiver Galileo too)

Thanks David and thanks to you all for the advice you gave me, I
carefully read all your replies and learned quite a few things.

At this point I think I'll start tinkering with the cheapest module I
can get (and it will probably be a LEA-5T). Once I'll have everything
set up, if I'll be still having fun, I'll consider buying a newer
module, probably from the Ublox M8 family. We will see.

73,
Paride
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Re: [time-nuts] Holdover, RTC for Pi as NTP GPS source

[ewkehren via time-nuts]

Tbolt is a good oneBert Kehren


Sent from my Galaxy Tab® A
 Original message From: David J Taylor via time-nuts 
 Date: 11/1/17  12:07 PM  (GMT-05:00) To: 
time-nuts@febo.com Subject: Re: [time-nuts] Holdover, RTC for Pi as NTP GPS 
source 
From: Mark Sims

I have an analytical balance that reads down to micrograms.   The weigh 
chamber is surrounded by three layers of IR absorbing glass so that radiated 
body heat does not induce convection currents in the air.   I worked on a 
balance that had nanogram resolution (mostly wishful thinking in that spec). 
It operated in a vacuum.  30 bit mass-to-digital converters are rather 
finicky beasties.

It does not take all that good of a temperature sensor to detect changes in 
room temperature due to body heat (or fetching a beer from the fridge in the 
next room).  You are basically a 100 watt space heater... even larger for 
the more corpulent folks.
==

Temperature is indeed the killer.  My best Raspberry Pis for time-keeping 
are RasPi-1 and RasPi-4, both of which are in an unheated cupboard not 
exposed to sunlight, on the north side of the house with indoor patch GPS 
antennas.

  http://www.satsignal.eu/mrtg/performance_ntp.php

Cheers,
David
-- 
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 

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Re: [time-nuts] PRS10 PRBB Shematics

[ewkehren via time-nuts]

The PRS10 was intended as FRS alternative you can use the same plug with no 
changes on both unitsBert Kehren


Sent from my Galaxy Tab® A
 Original message From: Mark Sims  Date: 
10/7/17  1:58 PM  (GMT-05:00) To: time-nuts@febo.com Subject: [time-nuts] PRS10 
PRBB Shematics 
SRS sells the connector.   You might want to make sure you have a tube of 
ass-lube handy when you check the price...  It's around three times the 
distribution price.  SRS really should have used a standard D-sub and a couple 
of SMA connectors.

I considered laying out a PRBB clone, but didn't want to mess with sourcing 
that damn connector.  I wound uo buying the PRBB and the heatsink (and a tube 
'o lube).   Spent more for those than the PRS-10.   The heatsink they ship now 
does not seem to be nearly as good as the older one.  Also be aware that the 
SRS ordering page is not HTTPS and your credit card info is sent in plain 
text...  you might want to order over the phone.
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Re: [time-nuts] True Position GPSDP + Rb X72

[ewkehren via time-nuts]

Starting with a 10 second clean up loop for a FEI 5680/GPSDO to now 600 Seconds 
using Wenzel's j circuit for the Tbolt we have a variety of boards. I am 
presently out of country but when back will gladly attach some board designs, 
material cost is minimal  if there is interest.Bert Kehren


Sent from my Galaxy Tab® A
 Original message From: Hal Murray  
Date: 9/23/17  9:39 PM  (GMT-05:00) To: Discussion of precise time and 
frequency measurement  Cc: hmur...@megapathdsl.net Subject: 
Re: [time-nuts] True Position GPSDP + Rb X72 

kb...@n1k.org said:
> If the main use is feeding test gear (and not direct synthesis) an Rb may do
> pretty well. Most instruments assume a dirty reference signal and clean it
> up internally.  

What's the bandwidth on the typical cleanup PLL?  How well does that match 
the noise from a Rb?


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] OCXO inside the FEI AN/URQ-23

[ewkehren via time-nuts]

Thanks I have 2. Will run some tests. In my opinion ADEV does hide changes in 
Frequency and we see it when we compare ADEV plots with at the same time 
frequency measurements. We see it with your plots on the Tbolt. The URQ shows 
frequency specs 2E-12 most likely ADEVBert


Sent from my Galaxy Tab® A
 Original message From: Tom Van Baak  
Date: 7/25/17  11:37 AM  (GMT-05:00) To: Discussion of precise time and 
frequency measurement  Subject: Re: [time-nuts] OCXO inside 
the FEI AN/URQ-23 
Bert,

In the early days of time-nuts the URQ-10, and especially the URQ-23, were 
highly sought after because of their reported stability. By now they are quite 
rare. Do you have one?

If it's important I can dig one out from the closet and run tests for you.

> "Question if it is frequency or ADEV".

I'm not sure what you mean. There is no such thing as "frequency" vs. "ADEV".

/tvb

- Original Message - 
From: "Bert Kehren via time-nuts" 
To: 
Sent: Tuesday, July 25, 2017 7:48 AM
Subject: [time-nuts] OCXO inside the FEI AN/URQ-23


> Has any one run tests of the OCXO inside the AN/URQ-23. Data in the manual  
> looks promising. Question if it is frequency or ADEV
> Bert Kehren


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Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse

[ewkehren via time-nuts]

Having  had a fan failure on a well insulated Rb we use a temperature sensor 
also used for compensation in to a PIC to shut down the systemBert Kehren

Sent from my Galaxy Tab® A
 Original message From: "David G. McGaw" 
 Date: 5/10/17  11:20 PM  (GMT-05:00) To: 
Discussion of precise time and frequency measurement  
Subject: Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse 
I too have had a fuse open up due to a failed thermistor in a HP10811.

David N1HAC


On 5/10/17 7:43 PM, Dan Rae wrote:
> As I reported the last time this subject came up, or maybe the time 
> before, the only time I had an open thermal fuse was in a 10811 that 
> had an open thermistor.  I was able to replace that and get the OCXO 
> working, but if the fuse had been replaced with a wire link I'm sure 
> the entire oven would have been toast.
>
> There have been two types of fuse fitted, all I those have are the 
> type that can be fitted with the plug in axial panasonic type, less 
> than a dollar from Digikey.  The older ovens had a different type but 
> I imagine it's similarly easy to replace.
>
> All my 10811s have the higher temperature Panasonic fuse fitted and I 
> sleep well at night...
>
> Dan
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Re: [time-nuts] Anyone using UBLOX LEA-M8F for GPSDO?

[ewkehren via time-nuts]

Neil we  have used M7 and I have boards contact me off list toBert Kehren 


Sent from my Galaxy Tab® A
 Original message From: Neil Smith G4DBN  Date: 
5/10/17  4:03 PM  (GMT-05:00) To: Discussion of precise time and frequency 
measurement  Subject: [time-nuts] Anyone using UBLOX 
LEA-M8F for GPSDO? 
I’ve just ordered an LEA-M8F board from CSG to save time and trouble making a 
PCB. I am intending to use it to discipline one of my 100MHz OCXOs, using a /5 
divider.  Has anyone on the list used this chip to discipline an external OCXO? 
Any experiences to share and suggestions to get best performance?  I have two 
100MHz OCXOs, one is locked to a G3RUH 10MHz GPSDO, the other to an Rb source.  
I use them to lock local oscillators for SHF transverters. I’ll be using this 
when out in the field with SHF sources up to 241GHz, so I don’t have to move 
the Rb source around.

No particular reason for choosing the LEA-M8F other than it looks interesting 
to play with. Actually, who needs a better reason!
Neil
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Re: [time-nuts] hm H Maser

[ewkehren via time-nuts]

Do we know what the PHM development for Galileo cost?




Sent from Samsung tabletBob Camp  wrote:Hi

> On Jan 10, 2017, at 2:45 AM, Dr. David Kirkby (Kirkby Microwave Ltd) 
>  wrote:
> 
> Once 9 Jan 2017 12:59, "Bob Camp"  wrote:
>> 
>> Hi
>> 
>> Ok here are some rough numbers:
>> 
>>> On Jan 9, 2017, at 4:35 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
> drkir...@kirkbymicrowave.co.uk> wrote:
> 
>>> It would be interesting to see your breakdown of the costs and man hours
>>> for an H2 maser. I suspect that others would find cheaper/faster
> solutions.
>> 
>> $100M for the H2
>> 
>> $25M for the Rb
> 
> With all due respect,  and I apprectiate you have a good knowledge of this
> field, but that's not a breakdown of costs or man hours I wanted to see,
> but a cost which appears to be plucked from the air.

Hardly plucked from the air. The last Rb design that I was involved with was 
roughly 5X that expensive. 

> 
> There's a BIG difference between a volunteer effort where
> 
> * Salaries are not paid
> * Items of test equipment are likely to be borrowed or people provide
> access to them for no charge etc,
> * Academics are likely to provide consultancy for free, in return for being
> on papers published.
> * Software licenses could probably be obtained free,  or enough people get
> trials.

That’s where the 5:1 cost reduction comes from. 

> 
> compared to a commercial company building a maser where
> 
> * Salaries are paid
> * All equipment is purchased new
> * Bench power supplies with 3.5 digit displays are sent out for calibration
> each year.
> *  No outside body will do anything except at a commercial rate.
> * Flights are booked for meetings which could be done over the Internet.
> * High end software licenses are huge.
> 
>> $500M for the fountain.
> 
> But on what basis do you arrive at that figure?

The numbers that the people who have done it come up with when you talk to 
them. 

> 
>> To get sponsorship for anything remotely close to those numbers, you
>> need to have some massively good credentials.
>> 
>> Bob
> 
> Yes agreed at $500M. But someone like Tom, who does have massively good
> credentials, could perhaps get $500,000, and perhaps that wisely spent
> could get a fountain built.  Without knowing how you arrive at $500M, it is
> not possible for anyone to look at ways of shaving that cost.


This is *not* a cheap field to be doing things in ….

Bob

> 
> The Lovell Telescope at Jodrell Bank in the UK was built on a shoestring
> budget. It was at the time the world's  largest steerable radio telephone.
> Half a century later only 2 larger ones have been built.
> 
> Maybe I am too nieve.
> 
> Dave.
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Re: [time-nuts] Tbolt issues

[ewkehren via time-nuts]

Know all that that is why we decided not to do it. Not knowing all the ins and 
outs and limits of the Tbolts that is why I asked the question to begin with
Bert Kehren




Sent from Samsung tabletCharles Steinmetz  wrote:Bert 
wrote:

> On our to do list was temperature control and clean up loop.  In order to do
> an analog clean up we need short interval changes and that is why  I went
> on the list since we have not been able to do it and looking at past  posting
> have not found data that will get us there.

To do any kind of "cleanup" at tau=1S, you need a source that is better 
at that tau than the one you are trying to clean up.  But if you have 
that, why use it to clean up something else?  Just use it as your 
standard.  (One might respond that the point would be to use the Tbolt 
to discipline the better oscillator at longer tau to correct drift, but 
you would need a very long time constant -- thousands of seconds -- 
which you cannot achieve with an analog loop.)  I do not think there is 
any realistic possibility of doing the kind of cleanup you propose in 
the analog domain.

Are you absolutely certain you tried the Tbolt with the damping set to 
10 seconds or more?  Did you let it settle for several weeks before 
deciding it wasn't doing what you need?

Perhaps you can try one last time:

1. Do a hard reset back to factory settings
2. Change TC to 500 seconds and damping to 10-12
3. Set recovery jam synch to "ON" with a threshold of 55-65 nS
4. Set recovery max offset frequency to >=1000 (this is in ppb)
5. Put it in an undisturbed location, inside a box of some kind
6. Let it sit for a month
7. Now, measure it

If this is better, but not quite good enough, try damping settings of 30 
and 100.

Alternatively, for a 10MHz reference you can just forget about and use, 
buy another PRS10 and discipline it with the PPS from the Tbolt.  I'd 
recommend buying a new one from SRS so you know that it has the PPS 
discipline feature and you could get help from SRS to optimize the 
discipline for your needs (the discipline is very adjustable and it is 
easy to get confused).

Best regards,

Charles


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Re: [time-nuts] FE-5680A software calibration units ?

[ewkehren via time-nuts]

Depends on who you got it from




Sent from Samsung tabletNick Sayer via time-nuts  
wrote:When I got it, the setting was zero. That suggests to me that the factory 
tuning was erased, assuming that the factory tunes it the same way - by 
changing the value adjusted by that software.

> On Sep 21, 2015, at 4:34 AM, Bob Camp  wrote:
> 
> Hi
> 
> Assuming it shows locked, that would suggest that (for what ever reason) 
> it’s been re-tuned at some point after it left the factory.
> 
> Bob
> 
>> On Sep 20, 2015, at 9:06 PM, Nick Sayer via time-nuts  
>> wrote:
>> 
>> 
>>> On Sep 19, 2015, at 4:20 PM, Nick Sayer via time-nuts  
>>> wrote:
>>> […]
>>> I’ve tested it against GPS and as it came, it had about a 0.5 ppm error.
>> 
>> Oops. That was supposed to be 0.5 ppb - 500 ppt.
>> 
>> 
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> 

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