[time-nuts] Re: GPSDO - GPS1300-10-1000 by RFX Ltd. UK

[Bryan _]

Hi Wilko:

I was not the OP, but I would be interested in the details of your project.

Cheers


-=Bryan=-

From: Wilko Bulte 
Sent: March 2, 2022 10:41 AM
To: Discussion of precise time and frequency measurement 

Subject: [time-nuts] Re: GPSDO - GPS1300-10-1000 by RFX Ltd. UK

hello Bryan,

Runnimg LH on a *Pi is feasible without any problems. I have built such a setup 
myself, it lives in my shack and is based on a Samsung UCCM GPSDO (telco 
surplus obtained in China). The Pi in question is an OrangePi Zero running 
Armbian Linux. It runs an Xdesktop on top of a VNCserver.  Obviously LH shows 
herself on that desktop ;-) This whole shebang allows running the 
GPSDO/OrangePi combo to run headless (i.e. without a display), one can use any 
VNCclient to check on LH via the network. Laptop, tablet, even a smartphone can 
be used to monitor the GPSDO. The OrangePi has both Wlan as well as wired 
Ethernet options.

Hope this makes sense, I did an article for Electron, the monthly of the Dutch 
VERON ham organisation. In Dutch, for obvious reasons. But can make it 
available if there is interest.

Wilko
PA1WBU

> On 2 Mar 2022, at 19:21, Bryan _  wrote:
>
> I have seen a project where ladyheather is run off a PI, suppose you could 
> just configure LH to display what you need.
>
> -=Bryan=-
>
> 
> From: va2...@ebox.net 
> Sent: March 2, 2022 9:34 AM
> To: Discussion of precise time and frequency measurement 
> 
> Subject: [time-nuts] Re: GPSDO - GPS1300-10-1000 by RFX Ltd. UK
>
> Hello to all members.
>
> I want to add to my lab a Pi based display that would show a GNSS SV map
> like the one attached to this message.
>
> Any suggestions ?
>
> Thank you !
>
> Claude VA2 HDD
>
>
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[time-nuts] Re: GPSDO - GPS1300-10-1000 by RFX Ltd. UK

[Bryan _]

I have seen a project where ladyheather is run off a PI, suppose you could just 
configure LH to display what you need.

-=Bryan=-


From: va2...@ebox.net 
Sent: March 2, 2022 9:34 AM
To: Discussion of precise time and frequency measurement 

Subject: [time-nuts] Re: GPSDO - GPS1300-10-1000 by RFX Ltd. UK

Hello to all members.

I want to add to my lab a Pi based display that would show a GNSS SV map
like the one attached to this message.

Any suggestions ?

Thank you !

Claude VA2 HDD


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[time-nuts] Re: Where do people get the time?

[Bryan _]

, and only after asking those on the "party line" to hang up, only those 
over 55 would know what I am talking about.

-=Bryan=-


From: Chris Howard 
Sent: January 6, 2022 6:56 PM
To: time-nuts@lists.febo.com 
Subject: [time-nuts] Re: Where do people get the time?


When I was a kid in the 1960's we got the time by calling a phone number.

"Bankers Trust time ten fifty three; temperature 46"
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[time-nuts] Re: local WWVB ?

[Bryan _]

That is a very impressive project.

-=Bryan=-


From: Robb via time-nuts 
Sent: December 11, 2021 5:48 AM
To: Discussion of precise time and frequency measurement 

Cc: Robb 
Subject: [time-nuts] Re: local WWVB ?

When there was talk a few years ago about this service going away I found this 
alternative: https://www.anishathalye.com/2016/12/26/micro-wwvb/

--
 Sent with Tutanota, the secure & ad-free mailbox.



Dec 10, 2021, 15:54 by lawrence.bra...@gmail.com:

> Hi Folks,
>
>
>
> I always like your discussions! Now I'd like to ask a question.
>
>
>
> Has anyone designed and/or sold a "WWVB repeater" device? I can picture a
> Raspberry Pi which had software to get NTP data or GPS-referenced time, and
> a small 60 kHz transmitter, which would send the proper WWVB timecode data
> to the several "atomic clocks" I have around the house.
>
>
>
> If not, I'll look into coding something for the Pi or maybe a M5Stack
> platform.
>
>
>
> Cheers,
>
>
>
> Larry
>
>
>
>
>
>
>
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[time-nuts] Re: GPS antenna question

[Bryan _]

If you really wanted to be particular about it you could follow Mr. Carlsons 
lab on his antenna project.

https://youtu.be/JjNsLEM6goM

-=Bryan=-


From: Robert DiRosario 
Sent: July 22, 2021 6:05 PM
To: time-nuts@lists.febo.com 
Subject: [time-nuts] GPS antenna question

If I want to use GPS for time and frequency standards, just how solidly
does the antenna need to be mounted?
The easiest and least expensive way to mount a GPS antenna would be up
on two 10' TV mast sections, but that
would move around a bit in the wind.  Maybe two or three inches.  Or do
I need to do better?  All of the "easy" or
"good" spots in my yard already have amateur radio antennas.

A second question, and it may very between different GPS receivers, how
to they get the time?  Do they just take one signal
with a good S/N number and correct for the distance from that satellite,
or do something more complicated with several signals?

Thanks
Robert
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Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

[Bryan _]

Not the previous links as but this/these ones

https://www.ebay.co.uk/itm/Neo-6M-NE0-7M-GPS-Mini-Satellite-Positioning-Module-51-SCM-MCU-For-Arduino/142760332765?hash=item213d2dcddd:g:U6oAAOSwXeJawafs

User on EEVBLOG mentions , true or not I don't know, but they did not have any 
luck.

https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/new/?topicseen#new

Starting at reply/post 890


-=Bryan=-


From: time-nuts  on behalf of Bob kb8tq 

Sent: February 20, 2021 1:53 PM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

Hi

What leads you to believe that these:

https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Are fakes?

Bob

> On Feb 20, 2021, at 3:40 PM, Bryan _  wrote:
>
> Apparently listing are fake Neo's, but perhaps unsoldering the pcb board may 
> be worth the money for a module swap. Although the not sure if the M8T is pin 
> compatible with the 7M modules. Don't see any documentation either, but I am 
> sure there is other similar boards out there on fleabay.
>
> https://www.ebay.co.uk/itm/Neo-6M-NE0-7M-GPS-Mini-Satellite-Positioning-Module-51-SCM-MCU-For-Arduino/142760332765?hash=item213d2dcddd:g:U6oAAOSwXeJawafs
>
>
> -=Bryan=-
>
> 
> From: time-nuts  on behalf of Bob kb8tq 
> 
> Sent: February 4, 2021 7:01 PM
> To: Discussion of precise time and frequency measurement 
> 
> Subject: Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning
>
> Hi
>
> Again, in case anybody else is interested ….
>
> https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
>
> Turns out to be a bit more than what the listing implies. The parts I got
> also came with a cable that goes from the round connector on the assembly
> to an HDMI connector. That explains the HDMI connector pinout information
> in the listing.
>
> The big ugly “plate” turns out to be easily removed from the assembly.
> That leaves you with a nice die cast box that is roughly 3 x 2.5 x 1”. It
> mounts to the plate via 4 small screws.
>
> Since you have a cable that fits the round connector, wiring it up to this or
> that should be pretty easy.
>
> Yes, the price keeps climbing ….
>
> Bob
>
>> On Jan 19, 2021, at 2:43 PM, Bob kb8tq  wrote:
>>
>> Hi
>>
>> I don’t know if anybody else bought any of these or not.
>>
>>> On Jan 9, 2021, at 10:20 PM, Bob kb8tq >> <mailto:kb...@n1k.org>> wrote:
>>>
>>> Hi
>>>
>>> Just for the sake of listing all the variations:
>>>
>>> https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
>>>  
>>> <https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649>
>>>
>>> Is the M8T on what I would *guess* is the original board. Simply from 
>>> looking at the picture I think
>>> you can guess pretty well what’s what on the board.
>>>
>>> Hint: If you buy quite a few …. errr … 10 … there s a pretty good chance 
>>> that something more than
>>> 20% might get knocked off the price …. I bought a pretty large pile of 
>>> stuff so it’s not clear if that
>>> had some impact on what offers got accepted …..
>>>
>>> If that’s not your favorite RF connector on the board, there are SMA’s that 
>>> likely fit in the same footprint.
>>>
>>> Bob
>>
>> If you did, the link now goes to a new auction (at a higher price).
>> That auction shows the board in it’s proper enclosure and provides a bit
>> more ( but not quite all) information on the module. Since they are now
>> free shipping a much heavier gizmo, that might explain some of the
>> price increase.
>>
>> If you look at the box, the connector on that box most certainly is not an
>> HDMI connector. However it *does* tell you what signals are running around.
>> You have the PPS out on RS-422. You also get the serial out of the module
>> on another RS-422 pair.
>>
>> The clock in / clock out stuff … no idea. The EXT-INT pin on the M8T is 
>> driven
>> by the 8051 CPU on the board. It’s a good bet that’s what those clocks are 
>> getting to.
>>
>> The TI switcher chip on the bo

Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

[Bryan _]

Apparently listing are fake Neo's, but perhaps unsoldering the pcb board may be 
worth the money for a module swap. Although the not sure if the M8T is pin 
compatible with the 7M modules. Don't see any documentation either, but I am 
sure there is other similar boards out there on fleabay.

https://www.ebay.co.uk/itm/Neo-6M-NE0-7M-GPS-Mini-Satellite-Positioning-Module-51-SCM-MCU-For-Arduino/142760332765?hash=item213d2dcddd:g:U6oAAOSwXeJawafs


-=Bryan=-


From: time-nuts  on behalf of Bob kb8tq 

Sent: February 4, 2021 7:01 PM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

Hi

Again, in case anybody else is interested ….

https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Turns out to be a bit more than what the listing implies. The parts I got
also came with a cable that goes from the round connector on the assembly
to an HDMI connector. That explains the HDMI connector pinout information
in the listing.

The big ugly “plate” turns out to be easily removed from the assembly.
That leaves you with a nice die cast box that is roughly 3 x 2.5 x 1”. It
mounts to the plate via 4 small screws.

Since you have a cable that fits the round connector, wiring it up to this or
that should be pretty easy.

Yes, the price keeps climbing ….

Bob

> On Jan 19, 2021, at 2:43 PM, Bob kb8tq  wrote:
>
> Hi
>
> I don’t know if anybody else bought any of these or not.
>
>> On Jan 9, 2021, at 10:20 PM, Bob kb8tq > <mailto:kb...@n1k.org>> wrote:
>>
>> Hi
>>
>> Just for the sake of listing all the variations:
>>
>> https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
>>  
>> <https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649>
>>
>> Is the M8T on what I would *guess* is the original board. Simply from 
>> looking at the picture I think
>> you can guess pretty well what’s what on the board.
>>
>> Hint: If you buy quite a few …. errr … 10 … there s a pretty good chance 
>> that something more than
>> 20% might get knocked off the price …. I bought a pretty large pile of stuff 
>> so it’s not clear if that
>> had some impact on what offers got accepted …..
>>
>> If that’s not your favorite RF connector on the board, there are SMA’s that 
>> likely fit in the same footprint.
>>
>> Bob
>
> If you did, the link now goes to a new auction (at a higher price).
> That auction shows the board in it’s proper enclosure and provides a bit
> more ( but not quite all) information on the module. Since they are now
> free shipping a much heavier gizmo, that might explain some of the
> price increase.
>
> If you look at the box, the connector on that box most certainly is not an
> HDMI connector. However it *does* tell you what signals are running around.
> You have the PPS out on RS-422. You also get the serial out of the module
> on another RS-422 pair.
>
> The clock in / clock out stuff … no idea. The EXT-INT pin on the M8T is driven
> by the 8051 CPU on the board. It’s a good bet that’s what those clocks are 
> getting to.
>
> The TI switcher chip on the board has it’s input clamped at 20V. It puts out 
> 6.2V. No
> idea what the correct input is. It seemed to be very happy with the 15V I put 
> on it.
> Pin 1 on J1 is power in. Pin 6 on J2 is ground. Ground also shows up on one of
> the mounting holes. The other pins on J2 appear to be 3 RS-422 pairs.
>
> All of the I/O lines are protected with clamp diodes. The antenna has multiple
> layers of protection. The debug pins on the C8051F320 come out to a connector
> that may or may not be populated on this or that board. There is a flash chip 
> on
> the back side and an EEPROM on the front. If somebody was more ambitious
> than I am, reprogramming the MCU to do fancy stuff might be possible.
>
> Fun !!!
>
> Bob

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Re: [time-nuts] WWVB BPSK Atomic Clock Receiver Modules

[Bryan _]

Shipping costs from Canada is horrendous, possibly what you ordered crossed the 
package/weight criteria for the cheaper shipping option

-=Bryan=-


From: time-nuts  on behalf of 
rcb...@atcelectronics.com 
Sent: February 13, 2021 11:58 AM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] WWVB BPSK Atomic Clock Receiver Modules

They reduced the price by 20% but they want $19.40 for shipping. I
decided I didn't need the development kit. I ordered one of the AM WWVB
kits back in early Nov and the shipping charge was only $4.50.


 Original Message 
Subject: [time-nuts] WWVB BPSK Atomic Clock Receiver Modules
From: Bryan _ 
Date: Fri, February 12, 2021 7:07 pm
To: Discussion of precise time and frequency measurement


Universal Solder has a Valentines day sale this weekend for up to 20%
for members. They sell the WWVB BPSK Atomic Clock Receiver Modules and
accessories for those interested.

https://www.universal-solder.ca/

Cheers


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[time-nuts] WWVB BPSK Atomic Clock Receiver Modules

[Bryan _]

Universal Solder has a Valentines day sale this weekend for up to 20% for 
members. They sell the WWVB BPSK Atomic Clock Receiver Modules and accessories 
for those interested.

https://www.universal-solder.ca/

Cheers


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Re: [time-nuts] Leagage, Tiny SA

[Bryan _]

IMSAI Guy on Utube does a lot of good videos on RF and he walked through the SA 
in a few videos and talked about spurs as well.

https://youtu.be/uwXUZSdxNq4   the same issues you are having might be 
discussed at 17:00

-=Bryan=-


From: time-nuts  on behalf of Gordon Batey 

Sent: January 16, 2021 9:15 AM
To: TimeNuts 
Subject: [time-nuts] Leagage, Tiny SA

Greetings,

I have one of those tiny SA also.

I appear to have a spur at 10 Mhz.  Bummer.  If anyone comes up with a
spur elimination solution please let me know.

I found this on the WIKI page; a sort of manual here:

https://www.hamcom.dk/TinySA/Description_of_TinySA_a_real_Spectrum_Analyzer_
for_little_money.pdf

Enjoy,

Gordon WA4FJC
Gpbatey  at  compuserve.com



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Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

[Bryan _]

Thanks for sharing, I purchased one of the scrap modules, not the PCB mounted 
ones. Good catch, but if I understand your post the error is in the schematic 
but not the actual boards themselves. I see no schematic in the listing (maybe 
removed). If the boards are faulty I would have thought there would be a lot of 
negative feedback.

And correct the seller is very good, fast shipping and items are as described.

-=Bryan=-


From: time-nuts  on behalf of Nigel gm8pzr 
via time-nuts 
Sent: January 9, 2021 2:38 PM
To: time-nuts@lists.febo.com 
Cc: gandal...@aol.com 
Subject: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

During the December conversation re LEA-M8T modules on scraps of PCB from Ebay 
I commented that the same seller also had complete circuit boards available, 
and suggested this might be a worthwhile alternative.

I've dealt with this seller before, always been very happy with the results, 
and agreed a price on three such modules which arrived just before Christmas, 
for reference this particular Ebay ID was 333619130232, and finally found time 
to start checking them today.
The modules themselves look very nice, but one of the auction photos is a 
connection diagram that shows Pin 2 of the 8 pin interface connector as "Power 
In 5V DC", and on this PCB that pin connects directly to the pin 6 Vcc input on 
the Ublox module, which has an absolute maximum rating of 3.6V ...whoops!
This is not intended in any way to be a criticism of this seller, who I am more 
than happy to recommend, nor indeed of any other seller, but this is a generic 
diagram that several sellers are using for various Huawei/Ublox modules, some 
of which may have an onboard 3.3V regulator, as presumably did the one this 
diagram originally referenced, but some of which may not.

So that's the warning folks, don't trust that diagram without checking!
Now a question, supposing someone did follow that diagram and applied 5 Volts 
to Vcc on the M8T, what is the risk of damage and would it be immediately 
obvious?
And no, I didn't:-), but when modules are described as tested concern might 
arise as to the test conditions.
Nigel GM8PZR
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Re: [time-nuts] Ublox 8T - breakout board

[Bryan _]

That's excellent, will you by chance be making the printed circuit board design 
public?

-=Bryan=-


From: time-nuts  on behalf of Matthias 
Welwarsky 
Sent: December 12, 2020 12:49 AM
To: time-nuts@lists.febo.com 
Subject: Re: [time-nuts] Ublox 8T - breakout board

On Samstag, 12. Dezember 2020 00:42:11 CET Bryan _ wrote:
> What is the difference between the LEA vs NEO variants other than
> mechanical, electrical specifications. Is one better for using as a GPSDO.

The LEA module has a built-in antenna bias circuit, you get a simple antenna
supervisor with just two external components. Apart from that they're using
the same core chipset.

I've attached the schematic for the LEA-M8 breakout board I'm doing for my own
purposes, the PCB is mostly ready, I'm just touching it up a bit to make it
look more tidy.

I plan to have it assembled using JLCPCBs SMT service, if any of you want to
tug along, I'll provide the BOM and part placement file together with the
gerbers so that it can be easily ordered.

I have some constraints regarding the connectors and some mounting holes and
overall size, but there's some space on the PCB left for small additions
should any of you have sensible suggestions.

About the only task left is to find a suitable LDO in their catalog. JLC have
recently up'd MOQ for many of their parts and they're also charging for
attrition. The LDO I was using before suddently costs $5 in small quantities.
I'll have to find a replacement.

BR,
Matthias

>
> -=Bryan=-
>
> 
> From: time-nuts  on behalf of Arnold Tibus
>  Sent: December 11, 2020 2:08 PM
> To: time-nuts@lists.febo.com 
> Subject: Re: [time-nuts] Ublox 8T
>
> Many thanks to all the timenuts for these interesting informations
> concerning *M8T* and for all other good ideas.
>
> My bad, I did not look careful enough to realize that in the ebay
> offer mentioned is not a *NEO* M8T but a *LEA* and I did order 2 units
> ... Fortunately that is not expensive. (Thank you Matthias, I did not
> know the difference before!).
>
> No I do not want to build my own module, I do have another problem.
> When I bought years ago a professional replacement board from a well
> known US-company equipped with the LEA-M8T I got it delivered with the
> 1st firmware which is not yet capable to work correct with GALILEO
> Satellites which I want to receive as well.
>
> The next bad point is, here in Germany I cannot get the new firmware to
> update the module (I had asked the representative for M8T). Sending it
> back and forth to the US-Company (insured an then on top the customs
> problem) is far out to be interesting ... so I falled into the trap with
> this offer. I thought to exchange just the receiver on the boards ...
> Perhaps somewhen I will find the correct new firmware to load onto the
> old original *NEO-M8T* ...
>
> In meantime I will continue working with my good old Thunderbolt.
>
> Many thanks to everybody
>   and good and healthy Xmas Time
> and good luck for all your projects!
>
> Arnold, DK2WT
>
> Am 10.12.2020 um 10:04 schrieb Matthias Welwarsky:
> > Dear all,
> >
> > If you go shopping for existing breakout boards:
> >
> > The ebay listing is for the *LEA-M8T*. It is mechanically and electrically
> > different from the *NEO-M8T*.
> >
> > BR,
> > Matthias
> >
> > On Montag, 7. Dezember 2020 14:25:35 CET ew via time-nuts wrote:
> >> With not much happening on Ublox 9T I went back looking at 8T in support
> >> for Jim Harnan's next generation GPSDO.. Shopping on ebay I ran across
> >> this super deal. No financial interest but we have bought from him
> >> repeatedly no problem. There is a reason he has 100%.. We have offered $
> >> 15 for three each all accepted.
> >>Bert Kehren
> >>
> >>
> >> https://www.ebay.com/itm/ON-SALE-1-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-M
> >> od
> >> ule/333753811808?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l26
> >> 49
> >>
> >> ___
> >> time-nuts mailing list -- time-nuts@lists.febo.com
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> >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and
> >> follow
> >> the instructions there.
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Re: [time-nuts] Ublox 8T

[Bryan _]

Thanks Bob, for what the seller is asking might be worth picking one up to play 
with.

-=Bryan=-


From: time-nuts  on behalf of Bob kb8tq 

Sent: December 11, 2020 5:08 PM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Ublox 8T

Hi

The LEA footprint is what uBlox sold as “T” variants in previous generations.
The NEO footprint is sorta kinda the “consumer” footprint. My guess is that
they decided to begin the process of moving everything over to a single
footprint. The LEA is there to drop into older designs. The NEO is what
you probably should use on new designs.

Spec wise (other than the footprint related stuff) there is no reason to prefer
the LEA over the NEO.

Bob

> On Dec 11, 2020, at 6:42 PM, Bryan _  wrote:
>
> What is the difference between the LEA vs NEO variants other than mechanical, 
> electrical specifications. Is one better for using as a GPSDO.
>
> -=Bryan=-
>
> 
> From: time-nuts  on behalf of Arnold Tibus 
> 
> Sent: December 11, 2020 2:08 PM
> To: time-nuts@lists.febo.com 
> Subject: Re: [time-nuts] Ublox 8T
>
> Many thanks to all the timenuts for these interesting informations
> concerning *M8T* and for all other good ideas.
>
> My bad, I did not look careful enough to realize that in the ebay
> offer mentioned is not a *NEO* M8T but a *LEA* and I did order 2 units
> ... Fortunately that is not expensive. (Thank you Matthias, I did not
> know the difference before!).
>
> No I do not want to build my own module, I do have another problem.
> When I bought years ago a professional replacement board from a well
> known US-company equipped with the LEA-M8T I got it delivered with the
> 1st firmware which is not yet capable to work correct with GALILEO
> Satellites which I want to receive as well.
>
> The next bad point is, here in Germany I cannot get the new firmware to
> update the module (I had asked the representative for M8T). Sending it
> back and forth to the US-Company (insured an then on top the customs
> problem) is far out to be interesting ... so I falled into the trap with
> this offer. I thought to exchange just the receiver on the boards ...
> Perhaps somewhen I will find the correct new firmware to load onto the
> old original *NEO-M8T* ...
>
> In meantime I will continue working with my good old Thunderbolt.
>
> Many thanks to everybody
>  and good and healthy Xmas Time
> and good luck for all your projects!
>
> Arnold, DK2WT
>
>
>
>
>
> Am 10.12.2020 um 10:04 schrieb Matthias Welwarsky:
>> Dear all,
>>
>> If you go shopping for existing breakout boards:
>>
>> The ebay listing is for the *LEA-M8T*. It is mechanically and electrically
>> different from the *NEO-M8T*.
>>
>> BR,
>> Matthias
>>
>> On Montag, 7. Dezember 2020 14:25:35 CET ew via time-nuts wrote:
>>> With not much happening on Ublox 9T I went back looking at 8T in support for
>>> Jim Harnan's next generation GPSDO.. Shopping on ebay I ran across this
>>> super deal. No financial interest but we have bought from him repeatedly no
>>> problem. There is a reason he has 100%.. We have offered $ 15 for three
>>> each all accepted. Bert Kehren
>>>
>>>
>>> https://www.ebay.com/itm/ON-SALE-1-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Mod
>>> ule/333753811808?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
>>>
>>> ___
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>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow
>>> the instructions there.
>>
>>
>>
>>
>>
>> ___
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>>
>
>
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Re: [time-nuts] Ublox 8T

[Bryan _]

What is the difference between the LEA vs NEO variants other than mechanical, 
electrical specifications. Is one better for using as a GPSDO.

-=Bryan=-


From: time-nuts  on behalf of Arnold Tibus 

Sent: December 11, 2020 2:08 PM
To: time-nuts@lists.febo.com 
Subject: Re: [time-nuts] Ublox 8T

Many thanks to all the timenuts for these interesting informations
concerning *M8T* and for all other good ideas.

My bad, I did not look careful enough to realize that in the ebay
offer mentioned is not a *NEO* M8T but a *LEA* and I did order 2 units
... Fortunately that is not expensive. (Thank you Matthias, I did not
know the difference before!).

No I do not want to build my own module, I do have another problem.
When I bought years ago a professional replacement board from a well
known US-company equipped with the LEA-M8T I got it delivered with the
1st firmware which is not yet capable to work correct with GALILEO
Satellites which I want to receive as well.

The next bad point is, here in Germany I cannot get the new firmware to
update the module (I had asked the representative for M8T). Sending it
back and forth to the US-Company (insured an then on top the customs
problem) is far out to be interesting ... so I falled into the trap with
this offer. I thought to exchange just the receiver on the boards ...
Perhaps somewhen I will find the correct new firmware to load onto the
old original *NEO-M8T* ...

In meantime I will continue working with my good old Thunderbolt.

Many thanks to everybody
  and good and healthy Xmas Time
and good luck for all your projects!

Arnold, DK2WT





Am 10.12.2020 um 10:04 schrieb Matthias Welwarsky:
> Dear all,
>
> If you go shopping for existing breakout boards:
>
> The ebay listing is for the *LEA-M8T*. It is mechanically and electrically
> different from the *NEO-M8T*.
>
> BR,
> Matthias
>
> On Montag, 7. Dezember 2020 14:25:35 CET ew via time-nuts wrote:
>> With not much happening on Ublox 9T I went back looking at 8T in support for
>> Jim Harnan's next generation GPSDO.. Shopping on ebay I ran across this
>> super deal. No financial interest but we have bought from him repeatedly no
>> problem. There is a reason he has 100%.. We have offered $ 15 for three
>> each all accepted. Bert Kehren
>>
>>
>> https://www.ebay.com/itm/ON-SALE-1-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Mod
>> ule/333753811808?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
>>
>> ___
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>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow
>> the instructions there.
>
>
>
>
>
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Re: [time-nuts] Surplus Navicom GPSDO

[Bryan _]

Wonder what he means by performs better?

This GPSDO is well built and performs better than other GPSDO we are selling, 
highly recommended.
Tested by Agilent 53220A with  Ex-ref from Trimble Thunderbolt GPSDO.


-=Bryan=-


From: time-nuts  on behalf of Gregory Beat 
via time-nuts 
Sent: November 14, 2020 1:52 PM
To: time-nuts@lists.febo.com 
Cc: Gregory Beat 
Subject: [time-nuts] Surplus Navicom GPSDO

Surplus Navicom RCGD-M units have recently appeared on eBay,
https://www.ebay.com/itm/312306372323
from reseller “EYT_GPS” (Shenzhen, China).  Lady Heather (used by reseller) 
identifies Navicom GPS receiver as Motorola (looks like Oncore footprint).
A bit of a mystery to the reseller, outputs/inputs to the FGPA on boards.
Tight, stacked assembly.
==
He has another unit, (cheaper) that uses the Furuno GT-8031F  GPS receiver 
module and an unknown OCXO.
https://www.ebay.com/itm/312306276819
==
He also has an assortment of Isotemp 10 MHz, still in their shipping trays.
Have fun experimenting!

greg, w9gb

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Re: [time-nuts] Changes in commercial GPS clocks over the decades

[Bryan _]

Great tutorial read on fiber in your website.

-=Bryan=-


From: time-nuts  on behalf of The Fiber Guru 

Sent: October 31, 2020 9:29 AM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Changes in commercial GPS clocks over the decades

Yes, prior to use of GPS to discipline the Local oscillator, telecom timing was 
a “trickle down” topology where a cesium source in Kansas City was distributed 
across the continent.

The cesium was the gold standard and as the timing signals cascaded to distant 
geographical regions, it was obviously less pure, so if cesium was at Stratum 1 
(stability), the next element in line that mediated time of downstream was at 
Stratum 2.  As it arrived at your local telco central office, it was at Stratum 
4 (ok, but useless in today sadly networks).

Enter GPS and instantly every local central office could achieve Stratum 1 
traceability, and if GPS was lost the best Rubidium's could holdover at Stratum 
2e (slightly better that Stratum 2).  If the clock had OCXO, holdover was 
Stratum 3 or 3e depending on the quality of the oscillator.

Stratum levels are reported to most network elements by embedding the Stratum 
value message in the Facility Data Link of an ESF T1 signal.  The network 
element would read the Stratum level from the incoming timing signal to 
determine if it should lock to the signal, or fall back to its internal clock, 
usually an ocxo at Stratum 3.

If the master GPS clock suffered loss of GPS and the backup oscillator 
deteriorated to a low stability, the clock would generate a message to the 
connected elements that said “Don’t Use Me” (DUS).  This method is called, 
“Sync Status Messaging/SSM”, and also carry’s over to the latest packet timing 
designs so that subtending elements always know the pedigree of a timing/sync 
signals.

It is notable that, while SSM provides a label as to the purported pedigree 
(stableness) of the timing signal, it is no guarantee the signal is actually as 
stable as reported, but generally it is truth.

This has been my world for several decades so please let me know if this 
information is not useful to this boardso we don’t fill your inbox with 
unwanted ramblings of an old telephone guy.  :)

The Fiber Guru
(www.fiber.guru<http://www.fiber.guru>)

> On Oct 31, 2020, at 10:42 AM, Magnus Danielson  wrote:
>
> Hi,
>
>> On 2020-10-30 21:37, The Fiber Guru wrote:
>> During my telco career I was responsible for Network Synchronization and
>> witnessed several generations of clock designs.  Post-telco I now
>> manufacture and sell Network synchronization systems.  Here are a few
>> observations from legacy and modern topologies:
>>
>>
>>
>> 1. BITS clocks used to consume an entire 8 ft rack in a large central office
> For those not in the Telco world. BITS is the US/ANSI term for the
> international ETSI/ITU-T term SASE. In telco system you have a central
> clock in the heart of the telephone station, so you route any
> synchronization signal incoming to the station through the SASE/BITS
> interface over to the SASE/BITS which then selected amongst available
> sourced and configuration locked up it's OCXO or rubdium to that and
> then distributed that out back. A modern SASE/BITS is a 6 U box.
> Applicable standards are ITU-T G.781 for routing, ITU-T G.812 for clock
> qualities and ANSI T1.101 for the specifics of the US system.
>> 2. Legacy clocks easily cost $35k to $50k
>>
>> 3. The most critical part of clock installation is the antenna..this has
>> never changed.  If you get this wrong the clock will flop around like a fish
>> out of water
> In traditional SASE/BITS installations, they never had a GPS antenna to
> start with, the system was designed to have analog cesiums as clock
> source, and frequency errors of 1E-11 was tolerated for the Primary
> Reference Clock (PRC). The PRC is specified in ITU-T G.811. Now the
> companies is competing in inventing harder and harder specs on PRCs
> based on what they modern cesium technology can deliver, but with
> marginal benefit to operators, which tend to follow the ITU-T a little
> too much because that used to be a safe route and a recepy for working
> solutions.
>>
>> 4. Most critical part of antenna installation is to have unobstructed view
>> of the sky, but not be the highest electrical element (for lightning
>> protectioncome of protection).  Of equal importance is selecting the
>> proper size antenna cable for the required distance (RG58 up to 100 ft,
>> RG213 up to 300 ft, LMR400 up to 600 ft)


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Re: [time-nuts] Assistance needed to understand some V_OCXO stability concepts.

[Bryan _]

That is a incredible project, well done !!. EEVblog forum is one of the better 
electronic forum boards out there. If you wanted to share your project, I am 
sure you will garner a lot of advice. I believe a number of members here are 
also contributors on EEVBLOG.

-=Bryan=-


From: time-nuts  on behalf of Jim Harman 

Sent: October 1, 2020 12:54 PM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Assistance needed to understand some V_OCXO stability 
concepts.

Hi Joe,

It looks like you have made a good start. If you have not already, I
suggest you review the design, code and particularly the write-up posted
here
https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/?all
on eevblog by Lars Walenius. His hardware design is a good deal simpler
than yours but is conceptually quite similar.

One significant difference is that his software incorporates a P-I
(Proportional - Integral) controller and it appears that you are only using
the P term.

Unfortunately Lars has passed away, but I have developed several GPSDOs
based on his concept and may be able to help if you have questions. My
latest design uses a TDC7200 time to digital converter chip to measure the
time between the PPS pulse and the oscillator.

To answer your specific questions,
At 10 Mhz,.a change of .3 Hz is 3e-5 / 10e6 = 3e-12 or 3 ppt. At 5 MHz
it would be twice that

A change in the DAC voltage over several hours may or may not translate
directly to a frequency change. It depends partly on how stable your
oscillator is with temperature and other factors and how much it is
drifting due to aging. The aging in turn depends on the quality of the
oscillator, how long it has been running and how long it was powered down
before that. You can get an indication of what to expect by studying OCXO
spec sheets.

The control loop is adjusting the DAC voltage to keep the oscillator at a
constant frequency based on the PPS pulses from the GPS. You can get an
indication of what is going on by looking at the DAC voltage, but you can't
tell for sure, which leads to Bob's comments that the only way to tell for
sure is to compare your GPSDO's frequency to a better reference.

HTH


--

--Jim Harman
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Re: [time-nuts] Frequency division by 81

[Bryan _]

I don't believe a picdiv can be used for frequencies above 20MHz. I believe 
even that is pushing the max frequency input capability of the pic


-=Bryan=-


From: time-nuts  on behalf of Bob kb8tq 

Sent: June 18, 2020 10:05 AM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Frequency division by 81

Hi

A lot depends on the output frequency of your OCXO. If it puts out 900 MHz,
that’s a bit different than if it puts out 9 MHz. For “normal” OCXO’s in the sub
30 MHz region, CMOS logic will do the division just fine. If a PICDIV is a 
candidate,
I’m guessing the OCXO is in this range.

You will be in the vicinity of 100 KHz with the output dividing from a 5 or 10 
MHz
OCXO. That means the noise floor of the logic is the main issue. The modern LVC
(and similar) logic families seem to have pretty good noise floors.

All this is just a guess without much to base it on …..

Bob

> On Jun 18, 2020, at 7:58 AM, Gilles Clement  wrote:
>
> Hi
> I need to divide the output of an OCXO by a factor D=81 for testing purposes. 
> So with minimum added phase noise.
> PICDIV-like approches would not work (D needs to be divisible by 8 or at 
> least be even)
> I went through the archives and it seems that an Injection Locked Frequency 
> Divider with resynchronization flip-flop could be a simple and acceptable 
> solution.
> As described in the following Wenzel paper: Unusual Frequency 
> Dividerswww.wenzel.com › uploads › dividers 
> <https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwik49qGpIvqAhURahQKHTBVClAQFjABegQIARAB&url=http%3A%2F%2Fwww.wenzel.com%2Fwp-content%2Fuploads%2Fdividers.pdf&usg=AOvVaw2m-9lURROiSbG9XykiDNDU>
> Does this make sense?
> Gilles.
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Re: [time-nuts] Spectracom 8131 Repair information

[Bryan _]

perhaps upload to the Ko4BB site for all to access. I can do so if you would 
like

http://www.ko4bb.com/getsimple/index.php?id=manuals


-=Bryan=-


From: time-nuts  on behalf of Byron Hayes Jr 

Sent: May 7, 2020 3:25 PM
To: Claude Houde ; Precise time and frequency measurement 

Subject: Re: [time-nuts] Spectracom 8131 Repair information

Claude,

I also have two Spectracom 8131s, one working and one not working, so I 
contacted the new parent company, Orolia, in March, 2019, and a very nice 
support person was able to find me the manual for the 8131, which is attached.  
I am sending this to the group, in case someone else needs this manual.

Byron, WA6ATN

At 12:39 PM 5/7/2020, Claude Houde wrote:
>Good day.
>
>I'm repairing a Spectracom 8131 and I believe that the OCXO is dead.
>
>In the Spectracom website they have the 8130 manual, and there is too much 
>difference between these two instruments to be useful.
>
>I searched in all the usual places to get the service manual for the 8131 and 
>either a catalogue or a data sheet for the OCXO, which is an Ovenaire OSC 
>42-15.
>
>If you have any information I would be very happy !
>
>Best regards,
>
>Claude VA2 HDD
>
>
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Re: [time-nuts] Vaperware Parts and pulse stretching circuits

[Bryan _]

They make quite a few models which one are you recommending?

-=Bryan=-


From: time-nuts  on behalf of Bill Notfaded 

Sent: April 25, 2020 5:38 PM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Vaperware Parts and pulse stretching circuits

I totally agree with the Metcal soldering station!!!  I'll never go back to
anything else.  I don't even use a scope.  I bought some magnifying glasses
with 5 sets of different power lenses you wear like glasses.  It has built
in led light and adjustable strap that hold it on your head off Amazon.
Works great.  I can do all small surface mount stuff with them.  Plus I
have my normal vision and hand eye coordination going that way.  Soldering
under a scope or on a video monitor is a lesson all in itself!

Bill

On Sat, Apr 25, 2020, 6:15 AM Gerhard Hoffmann 
wrote:

>
> Am 25.04.20 um 13:41 schrieb John Ackermann:
> > I do have a microscope (cheap Chinese unit, maybe $400 with articulated
> arm and the works) and it does make things much easier.  But as long as you
> can see the work, you can do the job.
> >
> > It's not that hard to do small pitch parts.  I usually do the best I can
> soldering individual pins, knowing their will be bridges, then clean up
> with solder wick and *lots* of no-clean flux.  You can never have too much
> flux.  I've found a 1.6 mm chisel tip is a good all around size for SMD
> work, though I have a 0.8 mm chisel available for when things get tight.
> >
> > The hardest part is getting the first couple of pins tacked down so the
> part is square on the pads.  After that it's fast.
> >
> > John
>
> I have about the same here, plus a cheap Chinese Ayoue852 hot air
> station. Exchanging the Weller for a Metcal was the biggest improvement
> after the LED ringlight for the microscope.
>
> In my quest to scrutinize the 1/f region, I have built some chopper
> amplifiers and the newest one will have GaN transistors that are nekkid
> chips with jut 4 tin bumps below. No case, just the passivated chip, 1 *
> 1 mm, EPC2038. Low channel resistance, even lower capacitance -> low
> charge injection. Resistors are 0603.
>
> Fearing I could not handle them, I made a minimum version of the switch
> itself as a test structure in an unoccupied corner of a different
> project. But soldering did take just 3 minutes, it was surprisingly
> easy. Just keep the air flow low enough, or you will have trouble to
> find the chips again. The thick-liquid flux helps to fix the chips in
> place.
>
> Legible part numbers on the board are hopeless at this scale. The board
> was made by PCBway, there were some discussions about having solder mask
> ON part of the pads, and some discussions with our German customs that
> you cannot buy 10 boards for $10 or so.
>
> The chips are the gray squares between the 2 vias on the left and the 4
> huge coupling capacitors.
>
> Cheers, Gerhard
>
>
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Re: [time-nuts] Yukon to make Daylight Saving Time permanent after final time change Sunday

[Bryan _]

Think the idea is to have the entire west coast from Alaska, BC and all the way 
down to California on one time zone. What I am not sure is how they incorporate 
this time change into electronic devices that auto adjust. If software driven 
no big deal I suppose.

-=Bryan=-


From: time-nuts  on behalf of Richard Solomon 

Sent: March 5, 2020 3:46 PM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Yukon to make Daylight Saving Time permanent after 
final time change Sunday

Or, you could be in Arizona. Most of the state,
but not all, does not do DST.

73, Dick, W1KSZ



On Thu, Mar 5, 2020, 4:32 PM Bryan _  wrote:

> In Canada apparently DST can be amended at the provincial level. Ongoing
> right now in BC is to follow what the Yukon is doing and get away from DST,
> but with trade to our neighbours to the south it's preferable everyone be
> the same. As I understand Washington and Oregon and I think California are
> following suit but require congress approval. If approved by Congress then
> BC will follow through.
>
> -=Bryan=-
>
> 
> From: time-nuts  on behalf of Bob kb8tq
> 
> Sent: March 5, 2020 3:17 PM
> To: Discussion of precise time and frequency measurement <
> time-nuts@lists.febo.com>
> Subject: Re: [time-nuts] Yukon to make Daylight Saving Time permanent
> after final time change Sunday
>
> Hi
>
> I suspect that DST is a decision you can make at the provincial /
> territorial level and that
> time zones are a federal level sort of thing ……
>
> Bob
>
> > On Mar 5, 2020, at 4:13 PM, Adrian Godwin  wrote:
> >
> > Would it be too pedantic to say they're ending DST but changing
> > their timezone ?
> >
> >
> > On Thu, Mar 5, 2020 at 9:03 PM Peter Vince 
> wrote:
> >
> >> I've just seen a news item on the Ganadian Global News website
> announcing
> >> that the Yukon will remain on Daylight Saving Time indefinitely after
> the
> >> forthcoming change to DST.  See:
> >>
> >>
> >>
> https://globalnews.ca/news/6633447/yukon-permanent-daylight-saving-time/
> >>
> >> Peter
> >> ___
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Re: [time-nuts] Yukon to make Daylight Saving Time permanent after final time change Sunday

[Bryan _]

In Canada apparently DST can be amended at the provincial level. Ongoing right 
now in BC is to follow what the Yukon is doing and get away from DST, but with 
trade to our neighbours to the south it's preferable everyone be the same. As I 
understand Washington and Oregon and I think California are following suit but 
require congress approval. If approved by Congress then BC will follow through.

-=Bryan=-


From: time-nuts  on behalf of Bob kb8tq 

Sent: March 5, 2020 3:17 PM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Yukon to make Daylight Saving Time permanent after 
final time change Sunday

Hi

I suspect that DST is a decision you can make at the provincial / territorial 
level and that
time zones are a federal level sort of thing ……

Bob

> On Mar 5, 2020, at 4:13 PM, Adrian Godwin  wrote:
>
> Would it be too pedantic to say they're ending DST but changing
> their timezone ?
>
>
> On Thu, Mar 5, 2020 at 9:03 PM Peter Vince  wrote:
>
>> I've just seen a news item on the Ganadian Global News website announcing
>> that the Yukon will remain on Daylight Saving Time indefinitely after the
>> forthcoming change to DST.  See:
>>
>>
>> https://globalnews.ca/news/6633447/yukon-permanent-daylight-saving-time/
>>
>> Peter
>> ___
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>> To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>>
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Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Bryan _]

On the point of using a MDA-3V at the hobbyist bench level, any issues that one 
needs to be concerned about. A few modification projects online, but none 
really comment on any issues or performance.

-=Bryan=-


From: time-nuts  on behalf of Bob kb8tq 

Sent: January 21, 2020 7:57 AM
To: Taka Kamiya ; Discussion of precise time and frequency 
measurement 
Subject: Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver 
options?

Hi

Cross talk between the reference in and the measured signal on the 53131 series 
can be an
issue . The counter drops resolution in the vicinity of 10 MHz as a result. 
There is also an  issue
with  the sampling process rather than direct feedthrough.

If you are measuring things like phase noise, having a lot of 10 MHz running 
around the lab will put a
spur in the phase noise plot. It may be close enough in that you don’t notice 
it every time. The same
sort of spur will play nasties with things like ADEV measurements. Getting a 
10V RMS signal down
120 db is tough …

Finally if you happen to be playing with radios, WWV is at 10 MHz. It does not 
take a lot of reference
signal to get back into the typical receiving antenna.

==

If you are daisy chaining counters, there are several ways to do it:

1) Drive the “ext ref in” and daisy chain off of “ext ref out”. This way the 
signal is buffered at each device.
It may add a bit of noise, but you can go a long way doing this.

2) Put a coax Tee connector at each instrument. If the device is high Z in, 
this can do ok. If it is a 50 ohm
termination all the time … not so much. Even with the high Z input it’s better 
for short runs than long ones.

3) Mix the two approaches. If you have a variety of gear, use the ones with ref 
in / ref out as buffers. String
the other gear in-between those boxes.

Bob

> On Jan 21, 2020, at 10:27 AM, Taka Kamiya via time-nuts 
>  wrote:
>
> I've tried daisy chaining 4 HP5335A.  By the time signal got to the 4th box, 
> it was too weak to reliably drive the 1 pps.  I had a terminator at the last 
> tee with short length of RG58s between boxes.  I guess some box puts 
> relatively heavy load on the signal?
>
> I'd like to know why 10V is a bad idea.  (besides too close to the upper 
> limit)  Cross talk between what/where?
>
> To OP:I have video amplifiers Extron MDA-3V successfully used for this.  1 
> port in, 3 ports out ones by Extron are very inexpensive at 10 dollars+/-.  I 
> never did formal testing but reading on all counters matched exactly.  They 
> are 75 ohms but it didn't matter in my use case.  You can change/adjust 
> internal resisters if you are concerned.
>
> ---
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
>On Tuesday, January 21, 2020, 7:45:22 AM EST, Bob kb8tq  
> wrote:
>
> Hi
>
> What are you driving?
>
> Most “normal” gear is pretty happy with a fairly wide range of input levels. 
> Obviously things
> like termination and long lengths of coax can get into the act. For 4 
> outputs, a passive splitter
> with 6 db of loss should do just fine. You have only taken the output voltage 
> down by 2:1 ….
>
> Just for reference:
>
> https://www.avionteq.com/Document/53131A-specification-sheet.pdf 
> <https://www.avionteq.com/Document/53131A-specification-sheet.pdf>
>
> Calls out a 200 mv to 10V RMS input level as acceptable For a variety of 
> reasons, 10V RMS
> is a really bad idea (cross talk ….). Lower is better in this case.
>
> Bob
>
>> On Jan 21, 2020, at 4:19 AM, skipp isaham via time-nuts 
>>  wrote:
>>
>> Hello once again to the Group,
>>
>> May I ask what the current relatively simple options are for
>> expanding a Thunderbolt or equivalent... output for distribution
>> to multiple devices?
>>
>> Although I expect only two or three isolated / buffered outputs
>> will be required in my example. I'm worried about signal level
>> if a passive system (Mini Circuits divider or equivalent type)
>> is used.
>>
>> Would appreciate a few quick opinions on what is practical and
>> seems to work well.
>>
>> thank you in advance
>>
>> regards,
>>
>> skipp
>>
>> skipp025 at yahoo dot com
>>
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Re: [time-nuts] thunerbolt, 2 problems

[Bryan _]

May be worth going over the board carefully with a loupe or microscope. FPGA 
could be fine but a input and some discrete components may be telling the FPGA 
to not turn on the pps, or dragging one of the inputs or outputs down to 
ground. Too bad there wasn't at least a block diagram available, or is there?

-=Bryan=-


From: time-nuts  on behalf of Bob kb8tq 

Sent: January 17, 2020 4:45 AM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] thunerbolt, 2 problems

Hi

There are no schematics for the TBolt. This is pretty typical of modern
devices from a number of outfits. From doing a bit of basic circuit
tracing, most of the “stuff” heads into or comes out of the FPGA or MCU.
Once you get past the basic interface chip you probably are looking at an
output pin on one or the other. In this case the FPGA is a pretty good bet.

Since there are no firmware images around for the FPGA or MCU, replacing
one is not practical. The firmware issue is  on top of dealing with getting a
crazy package off (and then back on) the board.

My *guess* is that Trimble “repaired” these parts by throwing the broken
one away and sending out a new one. That also has been a very common
thing for several decades now.

Bob

> On Jan 17, 2020, at 12:32 AM, Brian Lloyd  wrote:
>
> On Thu, Jan 16, 2020 at 9:20 PM Bill Beam  wrote:
>
>> Brian,
>> LH can do this.  Issue the command "p" to bring up the PPS control menu.
>>
>
> Thank you. LH does so much but finding the right command is a challenge.
>
> I did finally find a copy of tboltmon.exe. That and LH both report that
> 1pps is turned on. Nothing coming out. The Tbolt is locked and 10MHz is
> within range when compared with my other GPSDOs and my Rb. So it appears
> that the 1pps has failed. It appears that the 74AC04 is being used as a
> buffer to drive the output. I am seeing no pulse on the inputs or outputs
> of that chip so the 1pps is lost somewhere else.
>
> Does anyone have a schematic that I can use to trace back the 1pps?
>
>
>> On Thu, 16 Jan 2020 20:44:43 -0600, Brian Lloyd wrote:
>>
>>> After quite some time I dragged out my Tbolt and fired it up. Comes up
>>> OK. Lady Heather is happy. 10MHz is spot on (after an hour or so).
>>> Problem is, 1pps is missing. 1pps is enabled (or appears to be).
>>> Suggestions?
>>
>>> I am running Trimble Visual Timing Studio 2.03.12. It seems to know
>>> about the Thunderbolt-E but not the original thunderbolt. Not sure it
>>> will do the right thing. Does anyone have an older copy of the program
>>> for configuring the T-bolt?
>>
>>> Thanks in advance.
>>
>>> --
>>
>>
>>> n++ <https://www.lloyd.aero>
>>
>>> Brian Lloyd
>>> 706 Flightline
>>> Spring Branch, TX 78070
>>> br...@lloyd.aero <mailto://br...@lloyd.aero>
>>> +1.210.802.8359
>>
>>
>>> ___
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>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>
>>
>> Bill Beam
>> NL7F
>>
>>
>>
>>
>> ___
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>> and follow the instructions there.
>>
>
>
> --
>
>
>
> Brian Lloyd
> 706 Flightline
> Spring Branch, TX 78070
> br...@lloyd.aero
> +1.210.802-8FLY (1.210.802-8359)
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Re: [time-nuts] Using commercial video amplifier for 10MHz clock distribution.

[Bryan _]

There is a schematic here on the Extron uploaded by a TN member. The schematic 
for the Extron looks looks dead simple that one could really just make a simple 
3 channel with the included mods in the writeup, only problem is I don't see a 
source for a CLC409 any longer, and I don't have the experience or knowledge to 
use a substitute ADA800x ??

<http://www.ko4bb.com/getsimple/index.php?id=download&file=02_GPS_Timing/Extron_ADA_6_modifications_for_use_as_10MHz_distribution_amp_STEINMETZ.pdf>

-=Bryan=-


From: time-nuts  on behalf of ed breya 

Sent: October 18, 2019 1:39 PM
To: time-nuts@lists.febo.com 
Subject: Re: [time-nuts] Using commercial video amplifier for 10MHz clock 
distribution.

I have a Hitachi VD-1000 video distribution unit that's been sitting
unused for years, waiting until I finally get around to making it into a
reference unit. I just dug it out and looked inside. It is full of RCA
jack cables for jumping the signals around in different ways. I
apparently had changed things around already, to make one section into a
15-output distributor. I have forgotten all about it long ago, so now
it's just a dizzying array of cabling. I must have made notes somewhere,
that I'll have to find for when I eventually (probably fairly soon) do
the proper conversion.

It uses CLC404 amplifiers, which appear to be older and a little noisier
than the CLC409, but should be OK for this. Unfortunately, it uses a
small switching supply, which I dislike for things like this, so
ultimately will make a linear one for it.

This thing has 40 BNC connectors on the back, which would allow for lots
of I/O and branching combinations. This is likely way more than I'll
ever need, so the "new" plan is to incorporate some improvements,
considering what I recently learned during my work on the frequency
multiplier project. I'll be reducing the total fanout, and changing some
of the outputs to have fully-floating transformer coupling, to reduce
ground loop effects in high sensitivity applications, and also
independent volume controls for some. I may do the same on the source
inputs too. I don't know how many of each thing yet, but definitely
some. In any of the BNC spots, I can easily put an isolating type BNC,
or a volume control pot. The front panel is mostly blank, so there's
lots of room for even more stuff there. I just have to be careful to not
get carried away and make it too wonderful and complicated and never
finished.

I also have an Efratom something-something distribution rack with five
"MBF" modules that have four outputs each. They should pretty good too,
but unfortunately it's all for 5 MHz only - there's low- or band-pass
filtering built into each channel, so needs reverse engineering and mods
for 10 MHz. I vaguely recall looking for info on this about a year ago,
and stumbled upon an old time nuts thread. Someone (maybe Chuck Harris?)
had reported successful mods for 10 MHz on these, but there were no
links to any info about it. So Chuck, if you see this, and it was you,
or anyone else, I'd sure appreciate this info. If it was just my
imagination, then never mind.

Ed

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Re: [time-nuts] FA-2 Counter Questions

[Bryan _]

I think most of them are going here. Top of the page opens applet to upload.

http://www.ko4bb.com/getsimple/index.php?id=manuals


-=Bryan=-


From: time-nuts  on behalf of Richard Solomon 

Sent: October 1, 2019 10:06 AM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] FA-2 Counter Questions

Be happy to upload it if someone
can tell me where I should go to
do it.

73, Dick, W1KSZ

On Tue, Oct 1, 2019 at 3:35 AM Mark Sims  wrote:

> Can you post a copy of the manual?  Nobody that I've talked to has seen
> any manual or documentation.We've assumed that the "P" means the PLL is
> locked and the '*' indicates the unit has an input signal.
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Re: [time-nuts] GPS Antennas

[Bryan _]

Or a mfg. defect and thus why on the surplus market.

-=Bryan=-


From: time-nuts  on behalf of Denny Page via 
time-nuts 
Sent: August 29, 2019 7:39 PM
To: Discussion of precise time and frequency measurement 

Cc: Denny Page 
Subject: Re: [time-nuts] GPS Antennas

I think several people have run into that issue, including myself. It seems 
designed for a slightly tapered rod. Easy to fix with the right tool.

Denny

> On Aug 29, 2019, at 16:41, Ben Hall  wrote:
>
> Only issue with mine was that the thread wasn't fully cut, so I modified an 
> old taper tap to be a bottoming tap with the bench grinder and finished 
> tapping the hole to the bottom.


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Re: [time-nuts] Overseas buying?

[Bryan _]

I am in Canada and have sold items Stateside, scopes, etc. I prefer whenever 
possible to use regular parcel post. Once you get into using couriers, 
DHL/FedEx/UPS the seller really has to know their paperwork. When using mail, 
whether priority or regular mail the customs form is easy. Just make sure the 
sellers itemizes clearly on the customs form what the item is. I always clearly 
describe it and put hobby use/used. Customs is more forgiving when it comes to 
personal importation vs a business.

Being in the US you are allowed $800.00 importation before duty (although I 
have heard that states may grab some sales tax from you).


-=Bryan=-


From: time-nuts  on behalf of AC0XU (Jim) 

Sent: July 4, 2019 9:31 AM
To: time-nuts@lists.febo.com
Subject: [time-nuts] Overseas buying?

Anyone have suggestions about how to buy equipment from out of the country 
without getting US Customs delays?  I have the impression that precision timing 
devices are on some kind of US list of sensitive technologies, but Customs 
seems to also be concerned about importing such items.

I recently purchased an Oscilloquartz OCXO from a seller in France and FEDEX 
delayed delivering the item, requesting documentation about the item and about 
the purchaser (me) over and over again. I found FEDEX's communications to be 
atrocious - 7 different FEDEX people wanted me to email them information, and 
they kept asking me to email documents to paperw...@fedex.com, which bounced 
everything I sent it. For a few days, it looked like FEDEX was going to return 
the package, because they kept complaining that I wasn't responding to their 
requests for more information. Emails to them bounced. My phone calls to them 
went unanswered. Eventually FEDEX did release the package but it took over a 
week.

This was a frustrating experience and I am wondering what I should advise 
sellers in the future about how to document items so as to get through US 
Customs more smoothly. Any suggestions?

Thanks!
Jim


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Re: [time-nuts] Lady heather on a Raspberry pi

[Bryan _]

Texaspyro on eevblog has done it . He is the author of LH, sorry but forgot 
what user name he uses on Time Nuts.

http://www.eevblog.com/forum/projects/a-look-at-my-symmetricom-gpsdo-(ocxo-furuno-receiver)/

Page 35 for a picture of his project

-=Bryan=-


From: time-nuts  on behalf of Richard Solomon 

Sent: November 9, 2018 6:12 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady heather on a Raspberry pi

I have a couple of older Raspberry PI's (Model B+ and PI 3 Model B
that I would like to hook up to a Trimble T-Bolt. I also have a 7"
display (1024X600) that I could use.

What I don't have  is any info on hooking all this up and programming
the PI to run Lady Heather.

Is there any place on the Web that would provide me info on getting
all this together and programming it ?

Thanks for any leads,

Dick, W1KSZ

Sent from Outlook<http://aka.ms/weboutlook>

From: time-nuts  on behalf of Mark Sims 

Sent: Thursday, November 8, 2018 11:13 PM
To: time-nuts@lists.febo.com
Subject: [time-nuts] Lady heather on a Raspberry pi

Lady Heather uses the DTR and RTS modem control signals to control the fan.  If 
you are using a USB-Serial converter the code should work as-is.  Heather does 
not have any code specific to a particular type of hardware (such as the PI).

If you are using the PI GPIO serial port, you would need to modify the program 
to manipulate some GPIO pins.   This is probably best done in the functions 
SetDtrLine() and SetRtsLIne() in the heather.cpp file... there are Windows and 
Linux versions of these routines.

The functions apply_heat() and apply_cool() and hold_temp() in heathmsc.cpp 
could also be modified.  There is also some code to use a parallel port to 
control the fan, but that is rather Windows/DOS specific.  It could be modified 
for Linux.
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Re: [time-nuts] Oscilloscope-based measurements of frequency stability

[Bryan _]

The number of satellites. Yes, from LH

-=Bryan=-


From: time-nuts  on behalf of Dana Whitlow 

Sent: October 2, 2018 12:28 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Oscilloscope-based measurements of frequency stability

Hello Bert,

What is the cyan-colored trace seen in these screen shots?  And is
"1 ppt" the same as 1E-12 (just to be sure)?

Are these from LH?

Thanks,

Dana




On Tue, Oct 2, 2018 at 1:46 PM ew via time-nuts 
wrote:

> We see the glitches all the time, they exist and with proper equipment are
> very visible. These are telecom timing devices and the way they correct the
> 1 pps is by changing the frequency. Even LH shows it and it is very visible
> when you eliminate the other traces.What we call the Tbolt 2, the nicely
> packaged Trimle that also was part of the fraud listing does the correction
> once an hour. It is exact an hour function of when you powered it up.In my
> case night time spikes where mostly negative Air conditioner. Recovery is a
> function of the accumulated error. Standing next to it in front of my 19
> year old M300 it did effect the recovery  since my legs where within a
> foot. One picture shows the analog trace to.Original Tbolt does it
> constantly. We have spend a couple of years on this, hoping to optimize a
> clean up loop.so far no good results.Bert Kehren
> In a message dated 10/2/2018 1:04:50 PM Eastern Standard Time,
> tsho...@gmail.com writes:
>
> Dana, the short term few-ns jitter of the two phases, I think in a digital
> instrument is most likely data acquisition glitches.
>
> Even on a good old analog scope, jitter in the trigger circuit or jitter in
> amplitudes (with resulting changes in harmonic content and thus the shape
> of the curves) can cause the apparent zoomed in zero crossing to shift very
> similarly.
>
> In days of old the telco standards for frequency stability also included
> requirements for amplitude stability noise, directly related to making
> repeatable measurements using scopes. I'm gonna see if I can find some of
> those. I remember some crazy looking telco standard that required measuring
> amplitude noise on time scales measured in weeks.
>
> Tim N3QE
>
> On Mon, Oct 1, 2018 at 8:47 AM Dana Whitlow  wrote:
>
> > I cheered when I saw Dave B's "silly question", for
> > then I realized that I'm not the only one who likes
> > to measure things with an o'scope.
> >
> > I had purchased a GPSDO a few weeks before and
> > had  been observing its behavior relative to a free-
> > running Rb by watching 10 MHz sinewaves drift with
> > respect to each other as an aid in setting the Rb's
> > frequency.  However, I was seeing enough fairly
> > rapid random drift to limit the usefulness of this kind
> > of observation.  It dawned on me that I was sometimes
> > seeing drifts of several ns over the course of just
> > several seconds, thus implying that sometimes the
> > relative frequency error between the two sources was
> > reaching as high as roughly 1E-9.  I wanted to be able
> > to capture and plot a somewhat extended run of data
> > so I could try to understand this behavior better.
> >
> > Being TIC-less, I decided to see what I could do with
> > my o'scope, which is a Chinese-made 2-channel DSO
> > with synchronous sampling by the two channels and
> > with a respectable trace memory depth (28 MSA per
> > channel).
> >
> > I began this effort  in earnest a couple of days before I
> > saw Dave's question, and have only now brought it to
> > a sufficient state of completion to feel justified in reporting
> > some results.
> >
> > I am presently able to record about 45 minute's worth of
> > data as limited by the 'scope's trace memory, but my XP
> > computer's RAM space limits me to processing only about
> > 35 minutes of that in a seamless run.  Over that time
> > span I've seen a peak relative frequency discrepancy of
> > about 1.4E-9, with a handful reaching or exceeding 1E-9.
> > I've also measured average frequency differences between
> > the source's a a few parts in 10E11.
> >
> > Most of the effort went into developing a C program to do
> > the processing and then correctly scaling and displaying
> > the results in a form which I considered useful to me.  This
> > processing of course had to deal with an off-frequency and
> > drifting 'scope timebase, which is *horrible* compared to the
> > quantities under measurement (as expected from the outset).
> >
> > Present indications are that at t

Re: [time-nuts] Oscilloscope-based measurements of frequency stability

[Bryan _]

Interested as well

-=Bryan=-


From: time-nuts  on behalf of Chris Burford 

Sent: October 1, 2018 6:20 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Oscilloscope-based measurements of frequency stability

This sounds interesting enough and I would appreciate any notes or insight on 
doing this. I have a PRS10 and several GPSDOs that I would like to evaluate for 
performance on my scope.

Many thanks.


 Dana Whitlow  wrote:
> I cheered when I saw Dave B's "silly question", for
> then I realized that I'm not the only one who likes
> to measure things with an o'scope.
>
> I had purchased a GPSDO a few weeks before and
> had  been observing its behavior relative to a free-
> running Rb by watching 10 MHz sinewaves drift with
> respect to each other as an aid in setting the Rb's
> frequency.  However, I was seeing enough fairly
> rapid random drift to limit the usefulness of this kind
> of observation.   It dawned on me that I was sometimes
> seeing drifts of several ns over the course of just
> several seconds, thus implying that sometimes the
> relative frequency error between the two sources was
> reaching as high as roughly 1E-9.  I wanted to be able
> to capture and plot a somewhat extended run of data
> so I could try to understand this behavior better.
>
> Being TIC-less, I decided to see what I could do with
> my o'scope, which is a Chinese-made 2-channel DSO
> with synchronous sampling by the two channels and
> with a respectable trace memory depth (28 MSA per
> channel).
>
> I began this effort  in earnest a couple of days before I
> saw Dave's question, and have only now brought it to
> a sufficient state of completion to feel justified in reporting
> some results.
>
> I am presently able to record about 45 minute's worth of
> data as limited by the 'scope's trace memory, but my XP
> computer's RAM space limits me to processing only about
> 35 minutes of that in a seamless run.   Over that time
> span I've seen a peak relative frequency discrepancy of
> about 1.4E-9, with a handful reaching or exceeding 1E-9.
> I've also measured average frequency differences between
> the source's a a few parts in 10E11.
>
> Most of the effort went into developing a C program to do
> the processing and then correctly scaling and displaying
> the results in a form which I considered useful to me.  This
> processing of course had to deal with an off-frequency and
> drifting 'scope timebase, which is *horrible* compared to the
> quantities under measurement (as expected from the outset).
>
> Present indications are that at this level of GPSDO mis-
> behavior, the results I'm viewing are about 20 dB higher
> than the basic floor, which I am still characterizing.  I
> believe that the floor is limited primarily by uncorrelated
> sampling jitter between the two 'scope channels.
>
> If there is an expression of interest in this technique, I'll
> publish a detailed description of the technique and some
> plots showing results, probably in the form of an attachment
> in pdf format.
>
> Dana
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Re: [time-nuts] Programmable clock for BFO use....noise

[Bryan _]

I would be interested in hearing more of the more suitable classes of logic 
chips. I have a 20Mhz rubidium that I wanted to divide down to 10Mhz

-=Bryan=-


From: time-nuts  on behalf of Dana Whitlow 

Sent: September 14, 2018 12:55 PM
To: lstosk...@cox.net; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Programmable clock for BFO usenoise

Frequency dividers can be pretty low noise, if you choose the right class
of logic.  I remember that
at one time in the distant past, LSTTL was considered king.  Unfortunately
I've been out of touch
with frequency dividers long enough to be ignorant of what works well today.

i'd suggest trying something with either HC-series or AC-series CMOS,
chances are fair that you'd
be happy.  Write me off list and I'll tell you which well-known distributor
still has an excellent
selection of HC and AC parts in stock.

Dana


On Fri, Sep 14, 2018 at 11:14 AM,  wrote:

> Off topic for this list, but you guys are experts in oscillator noise!
>
> Playing with some mechanical filters.  Need USB and LSB crystals for the
> BFO.  No one seems to make crystals anymore, especially in the 253 KHz
> range!
>
> Looking at the DigiKey Cardinal programmable oscillators.  Cheap and
> available: CPPC1LZ A5B6
>
> Anyone have an idea how noisy these would be after a division by 4 to get
> them in range?
>
> Thanks,
>
> N0UU
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Re: [time-nuts] PLL/GPSDO/etc learning resources for mere mortals

[Bryan _]

Hello:

Is there any other recommendations for a GPS receiver module, I note you 
recommend the Neo7M, but wondering if there are others that can be considered. 
Is there some better suited to supplying a frequency reference. There is also 
the 8M/T model(s) and the Venus, but not sure as to what 
advantages/disadvantages they have. I was going to start with a old Jupiter-T 
TU60-D120 module that I have as it has a 1pps output.


6.1.1 Pin J1-6: 1PPS output This signal is a positive going pulse with the 
leading edge being the point of measurement for synchronisation with the GPS 
satellite transmissions. The pulse width is approximately 26 ms.

Regards

-=Bryan=-


From: time-nuts  on behalf of Lars Walenius 

Sent: September 7, 2018 12:25 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] PLL/GPSDO/etc learning resources for mere mortals

I heard Jim mentioned my GPSDO. I would not go to the time nuts archive as that 
describes a far from ready software design. The hardware is almost identical. 
Last year I published a new design on EEVBlog:

https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/?all

This is a, as I think, a much more robust design and much more tested. By just 
setting the”gain” it will make a stable 1Hz digital PLL. As the DAC can be set 
and you have a counter with 1ns resolution you don’t need any extra instruments 
to do this. The nice thing is that the controller is very flexible and can 
handle all kinds of 10MHz oscillators as XO, TCXO, OXCO and rubidium. The 
useful control range of the oscillators is 0.001-6ppm. As only a 1PPS with 
3.3-5V amplitude is needed a wide variation of GPS modules can be used. The 
time constant can be set from 4 to 32000 seconds and stored in EEPROM.

In the 21 pages of instruction I describe the design and also give performance 
data as both a GPSDO and a time interval counter. As Jim says my GPSDO gives 
useful information how you can do your own GPSDO. On the first pages I have 
some discussion of the GPS modules like NEO7M that can be used and also about 
different oscillators. Note I think the oscillators are the first you should 
think of as they set the most important specs for the GPSDO. See also the user 
manual for Stanford FS740 that contains a lot of information about a modern 
GPSDO. Here the link to Stanford FS740 seems to be broken in my instruction. 
Today this worked: https://www.thinksrs.com/downloads/pdfs/manuals/FS740m.pdf  
See for example pages 25-35 for a good description of the GPSDO part. In the 
end of the manual you also find complete schematics!

On pages 8-9 in my instruction you find a very short description of my software 
and it is a standard PI-loop with a low pass filter before just as in the 
FS740. Paul-Henning has a very simple introduction to the PI-loop that I like 
http://phk.freebsd.dk/time/20141018.html  . I would also recommend learning 
from the GPSDO simulator by Tom Van Baak 
http://www.leapsecond.com/pages/gpsdo-sim/   it also uses a PI-loop + low pass 
filter and his code tells you a lot.

>From Tom’s GPSDO simulator you can also learn how the time resolution and the 
>DAC resolution work with real time data. Magnus Danielsson in March 2014 
>published the result of some his simulations with different time and DAC 
>resolutions on time nuts. My takeaway was that a time resolution below 5-10ns 
>was ok and DAC resolutions in the ballpark of the oscillator ADEV was fine, 
>but have a look on his data.

On page 15 in my instruction you find a list of basic links that I have found 
useful. Some links seems broken so for example for Stanford’s you have to find 
again on their homepage.

On pages 16-17 you find help commands and description of serial information. By 
the way Mark Sims excellent LH can read this and use the time, DAC and 
temperature data that are spit out every second 
http://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/?all
  . This together with the GPS module of choice serial output data should make 
this very useful. I am sorry I haven’t used this as I am very weak of chemo and 
haven’t done anything to my GPSDO for a long time.

Page 18 shows setup to read for example DAC data into Timelab.

On page 19 you find some ADEV results of two of my prototype GPSDO’s. One with 
a TCXO DOT050V and one with a OCXO 131(that by purpose uses a bad DAC 
resolution of 1.2E-11 but still gets ADEV’s in the 5E-12 range.

Last two pages show data with the controller used as a time interval counter. 
By measuring the TIC with a PICDIV PD26 it is possible to enter a few 
linearization parameters in EEPROM and get ADEV’s in the 8E-10 range at 1sec.

Even if I don’t recommend reading specific about my GPSDO on time nuts I really 
recommend to search and read the time nuts archive. It is a lot of useful 
information and a special thank to Bob kb8tq who contri

Re: [time-nuts] Bicentennial GOES satellite clock

[Bryan _]

There have been a few television documentaries over the years on the Carrington 
event of 1859.


https://www.history.com/news/a-perfect-solar-superstorm-the-1859-carrington-event




-=Bryan=-



From: time-nuts  on behalf of David I. Emery 

Sent: August 12, 2018 6:36 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Bicentennial GOES satellite clock

On Sun, Aug 12, 2018 at 07:48:52PM -0400, Bob kb8tq wrote:
> Hi
>
> Well???. there???s also the solar flare that vaporizes the planet earth :)
>
> A flare big enough to take out all the sat systems would disrupt a lot more 
> than just navigation.
> It also probably is big enough to take out HF radio gear as well. It takes a 
> *lot* of energy to
> permanently take out a sat system. Hour or two disruptions ??? sure ??? total 
> destruction, that???s
> getting into crazy levels.

Not so clear, big events can cause satellites to fail due to
large charges and voltages on induced on surfaces of the bird that cause
arcs - and also bombardment by energetic particles that can cause logic
states in chips to get tweaked (SEDs) and crash the control electronics
and CPUS and/or confuse vital sensors..  causing the bird to enter modes
that may not be safe for it or recoverable - more than a few satellites
have died of these kinds of things.

Whether ENOUGH GPS/Galileo/Glonnass/Baideu birds would fail to
eliminate them as a functioning constellation is probably somewhat
unlikely... however.

But It is much more likely that orbits would be less accurately
known for a while due to atmospheric heating and increased drag and
maybe also due to disturbances in satellite orientation and power and
thermal status during the event that could both change drag and perhaps
even induce slight impulses if gas jets or similar means were required
to recover the bird and make it stable again.   And the power and
thermal perturbations in emergency mode shutdown configurations might
well impact the on board clock performance and accuracy (even maybe just
from the extra radiation as the magnetopause moved inside the satellite
orbits in an extreme event).

So in addition to the disturbed propagation through the
ionosphere causing degraded performance there well could be significant
errors in ephemerides (basic bird position) that would do so too for a
while.

And recovering a whole constellation of confused, sick and
dangerously misconfigured satellites during a massive world wide event
might be less easy than one might first imagine as the resources
required on the ground would probably be damaged and disabled by other
effects (massive nation wide power grid collapses and the like) and
would certainly be stretched thin by all the urgent problems to get
under control before individual  satellites started to become nearly or
completely unrecoverable.

And there are certainly positive feedback vicious spiral effects
here - such as lack of time and position accuracy caused secondary
problems such as  sync failures in fiber rings and the like that might
take out parts of the Internet and cell systems) and make it much harder
to recover the satellites due to lack of effective communications on the
ground.

I'd expect that decently designed HF and LF radio time and
positioning systems would be VERY much more resistant to lethal damage
by flare EMPs... hard to see how massive earth magnetic events could
kill LF or HF receivers that were even modestly hardened against EMP
simply because otherwise local lightning would be frying them regularly.

And the HF and LF transmitters involved should be pretty self
protecting too... maybe their power supply would be the weak point as
the grid collapsed but this is a problem that can be cheaply handled
with well known and proved diesel generator technology.



--
  Dave Emery N1PRE/AE, d...@dieconsulting.com  DIE Consulting, Weston, Mass 
02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in
celebration of what could have been, but wasn't and is not to be now either."


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