Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

[Bob Camp]

Hi



> On Jun 9, 2016, at 3:31 PM, Nick Sayer via time-nuts  
> wrote:
> 
> 
>> On Jun 9, 2016, at 10:11 AM, Bob Camp  wrote:
>> 
>> 
>> One very real possibility is: The reason we *have* all these parts is that 
>> they
>> have a bug in them, and were scrapped out  because of it.
>> 
> 
> From what I’ve read elsewhere (and I can’t find a citation right now), they 
> (at least the FE-5680As) were used in cell phone bases that were 
> decommissioned after network upgrades.

That’s always been the leading theory. It matches up with the reason you 
see a lot of other ex-cell gear out of China. It may or may not be correct
in this case. We never ever seem to get a fully authoritative answer to those
sort of questions.

Bob

> 
>> Bob
>> 
>> 
>>> On Jun 9, 2016, at 8:03 AM, Clint Jay  wrote:
>>> 
>>> It would seem so bit I don't remember seeing a 'reset'  chip in the 5680.
>>> I'm wondering if there's scope to add one onto the rail that runs the PSD
>>> and 80C320 to keep it in reset.
>>> On 9 Jun 2016 13:00, "Bob Camp"  wrote:
>>> 
 Hi
 
 Based on the number of different ways there seem to be to corrupt the
 operating software
 in the FE Rb’s …. they seem to have a unique problem. There are a *lot* of
 devices
 using the same basic parts that don’t turn into a brick when this or that
 happens.
 
 Bob
 
> On Jun 9, 2016, at 4:31 AM, Hal Murray  wrote:
> 
> 
>> The ATTinys have brownout detectors in them that’s supposed to keep them
>> from going bonkers during undervolt periods.
> 
> Startup and/or brownout has long been a nasty problem area for digital
> designers.
> 
> In the old old days, there was typically a R/C delay on the reset pin to
 a
> CPU.  That screwed up when the power supply ramped up slowly enough.
 Most
> old timers have that merit badge.
> 
> Modern CPU chips often have specs like power must be OK for 200 ms before
> releasing Reset.  Anything like that will have at least one corresponding
> power monitor chip with several supply voltage inputs and the appropriate
> delay.
> 
> The brownout side gets ugly when you look at the tolerances.  The
 tolerance
> on the power monitor subtracts from the power supply tolerances.
> 
> There is another worm in the can.  How long does it take for your
 oscillator
> to get going?
> 
> 
> 
> --
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] FE-405B reprogramming

[Skip Withrow]

Hello time-nuts,

I'm a little late on this discussion, but I too was very intrigued by the
possibility of a 10MHz FE-405B.  I have tried it and it is possible
(maybe), there is still one big hurdle to get over.

1. There is a 15MHz crystal filter at the output of the 405.  This was
easily and cheaply replaced with a 10MHz unit.

2. There is a 15MHz (third overtone) crystal in the VCXO. This drives the
DDS and the output.  With some playing (new crystal and two component
deletions) this was changed to 10MHz.  BTW, this is not the 'good' crystal
that is ovenized and gives the FE-405 it's really good numbers.

3. The DDS is normally 15MHz in, 5MHz (+/-) out that is locked to the
'good' crystal.  So, it is reprogrammed to be 10MHz in, 5MHz (+/-) out.

It works, kinda.  The 15:5 ratio is enough to satisfy the Nyquist criteria
and a normal 405 is happy.  The 10:5 ratio creates some very interesting
outputs from the DDS, There is a very large low frequency component that
drives the PLL wacky.

I suppose there are several ways to get around this problem, but I was
looking for a way to change the unit with just minimal component changes.
Doesn't look like that can happen

I'm convinced now that the right way to do it is use a divider
(regenerative or otherwise) to get there from here.

Regards,
Skip Withrow


Virus-free

<#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
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Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

[Nick Sayer via time-nuts]

> On Jun 9, 2016, at 10:11 AM, Bob Camp  wrote:
> 
> 
> One very real possibility is: The reason we *have* all these parts is that 
> they
> have a bug in them, and were scrapped out  because of it.
> 

>From what I’ve read elsewhere (and I can’t find a citation right now), they 
>(at least the FE-5680As) were used in cell phone bases that were 
>decommissioned after network upgrades.

> Bob
> 
> 
>> On Jun 9, 2016, at 8:03 AM, Clint Jay  wrote:
>> 
>> It would seem so bit I don't remember seeing a 'reset'  chip in the 5680.
>> I'm wondering if there's scope to add one onto the rail that runs the PSD
>> and 80C320 to keep it in reset.
>> On 9 Jun 2016 13:00, "Bob Camp"  wrote:
>> 
>>> Hi
>>> 
>>> Based on the number of different ways there seem to be to corrupt the
>>> operating software
>>> in the FE Rb’s …. they seem to have a unique problem. There are a *lot* of
>>> devices
>>> using the same basic parts that don’t turn into a brick when this or that
>>> happens.
>>> 
>>> Bob
>>> 
 On Jun 9, 2016, at 4:31 AM, Hal Murray  wrote:
 
 
> The ATTinys have brownout detectors in them that’s supposed to keep them
> from going bonkers during undervolt periods.
 
 Startup and/or brownout has long been a nasty problem area for digital
 designers.
 
 In the old old days, there was typically a R/C delay on the reset pin to
>>> a
 CPU.  That screwed up when the power supply ramped up slowly enough.
>>> Most
 old timers have that merit badge.
 
 Modern CPU chips often have specs like power must be OK for 200 ms before
 releasing Reset.  Anything like that will have at least one corresponding
 power monitor chip with several supply voltage inputs and the appropriate
 delay.
 
 The brownout side gets ugly when you look at the tolerances.  The
>>> tolerance
 on the power monitor subtracts from the power supply tolerances.
 
 There is another worm in the can.  How long does it take for your
>>> oscillator
 to get going?
 
 
 
 --
 These are my opinions.  I hate spam.
 
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
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>>> 
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Re: [time-nuts] GPS altitude somewhat wrong?

[Gary E. Miller]

Yo Hal!

On Thu, 09 Jun 2016 02:12:53 -0700
Hal Murray  wrote:

> g...@rellim.com said:
> > While you are waiting check out the attached scatter plot.  Now
> > THAT is a good $25 GPS!  Beats the heck outta any Garmin.  CEP(95)
> > of 1.5 meters over 1,000 seconds.  
> 
> What type of GPS was that?

Skytraq  NS-HP.  With the S2525F8-RTK chip in it.

http://navspark.mybigcommerce.com/ns-hp-rtk-capable-gnss-receiver/

I see they have a new firmware update, they have been tweaking it
as it is a new-ish chip.  Time for me to re-flash.

RGDS
GARY
---
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com  Tel:+1 541 382 8588


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Re: [time-nuts] GPS altitude somewhat wrong?

[Gary E. Miller]

Yo Mark!

On Thu, 9 Jun 2016 16:56:12 +
Mark Sims  wrote:

> You have to be careful with a lot of modern GPS receivers.   Many
> implement some sort of "position pinning".   If they do not detect
> significant movement,  they either stop updating the coordinates  or
> heavily filter it...  you do not see the actual computed location.
> On some receivers you have to move well over 10 meters before the
> position un-pins. --
> > CEP(95) of 1.5 meters over 1,000 seconds.


Yes, but this model Skytraq is designed for survey work.  So that mode
is selectable.

RGDS
GARY
---
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com  Tel:+1 541 382 8588


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Re: [time-nuts] GPS altitude somewhat wrong?

[Van Horn, David]

-Original Message-
From: time-nuts 
[mailto:time-nuts-bounces+david.vanhorn=backcountryaccess@febo.com] On 
Behalf Of Michael Perrett
Sent: Wednesday, June 8, 2016 4:33 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS altitude somewhat wrong?

A couple of things come to mind:
1) Is this a single measurement or an average over at least 24 hours?

60+ hours

2) Did you get your elevation via the receiver survey mode (recommended)?

This is what's currently being displayed in LH after a 60 hour survey

3) How close is your "nominal" elevation measurement and what makes you think 
it is truth?

Damifino.  :)

4) The vertical component of the GPS position solution is typically 50% worse 
accuracy and a lot noisier than the horizontal measurement. If you have a good 
horizontal measurement it is unlikely you have a "wrong answer"
on elevation since your receiver is using the same data, just solving the 
equation for a different variable.

5) What is your satellite mask angle? The geometry (hence accuracy) degrades as 
an increasing function with mask angle. Suggest for the survey mode you use as 
low a mask angle as possible (typically 5 to 10 degrees).

Currently set to 5 degrees, which I know is low, but I wanted to see what the 
whole sky map looks like.
I will dial it up as we get things settled in.


Finally, your 214' error is outrageous. For a surveyed position the answer 
should be with +/- 10'.

Ok..



Michael Perrett

On Wed, Jun 8, 2016 at 1:33 PM, Van Horn, David < 
david.vanh...@backcountryaccess.com> wrote:

>
> I have just installed a Thunderbolt here to get our time and frequency 
> equipment all on the same page.
> As I was looking at the display on Lady Heather, I was noticing that 
> the GPS altitude seems rather wrong.
> We are in Boulder CO, which is nominally 5430' and the antenna is 
> about 20' off the ground.
> The display (near overdetermined position) reads 1589.72991 meters or 
> 5216 and change in feet.
> Altitude is a big deal around here. :)
>
> I suppose 214' isn't that outrageous, but it does bring me to a question:
>
> How accurate is the altitude number really?
>
> Thanks.
>
>
> --
> David VanHorn
> Lead Hardware Engineer
>
> Backcountry Access, Inc.
> 2820 Wilderness Pl, Unit H
> Boulder, CO  80301 USA
> phone: 303-417-1345 x110
> email: david.vanh...@backcountryaccess.com david.vanh...@backcountryaccess.com>
>
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Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

[Bob Camp]

Hi

Their design is hardly unique in not having a dedicated supervisory part in it.
There are a *lot* of designs that work very well using basically the same 
parts they use, without using a reset chip. 

Without a lot of digging into exactly what is going on, there isn’t much of a 
way to be sure of a fix. 

One very real possibility is: The reason we *have* all these parts is that they
have a bug in them, and were scrapped out  because of it.

Bob


> On Jun 9, 2016, at 8:03 AM, Clint Jay  wrote:
> 
> It would seem so bit I don't remember seeing a 'reset'  chip in the 5680.
> I'm wondering if there's scope to add one onto the rail that runs the PSD
> and 80C320 to keep it in reset.
> On 9 Jun 2016 13:00, "Bob Camp"  wrote:
> 
>> Hi
>> 
>> Based on the number of different ways there seem to be to corrupt the
>> operating software
>> in the FE Rb’s …. they seem to have a unique problem. There are a *lot* of
>> devices
>> using the same basic parts that don’t turn into a brick when this or that
>> happens.
>> 
>> Bob
>> 
>>> On Jun 9, 2016, at 4:31 AM, Hal Murray  wrote:
>>> 
>>> 
 The ATTinys have brownout detectors in them that’s supposed to keep them
 from going bonkers during undervolt periods.
>>> 
>>> Startup and/or brownout has long been a nasty problem area for digital
>>> designers.
>>> 
>>> In the old old days, there was typically a R/C delay on the reset pin to
>> a
>>> CPU.  That screwed up when the power supply ramped up slowly enough.
>> Most
>>> old timers have that merit badge.
>>> 
>>> Modern CPU chips often have specs like power must be OK for 200 ms before
>>> releasing Reset.  Anything like that will have at least one corresponding
>>> power monitor chip with several supply voltage inputs and the appropriate
>>> delay.
>>> 
>>> The brownout side gets ugly when you look at the tolerances.  The
>> tolerance
>>> on the power monitor subtracts from the power supply tolerances.
>>> 
>>> There is another worm in the can.  How long does it take for your
>> oscillator
>>> to get going?
>>> 
>>> 
>>> 
>>> --
>>> These are my opinions.  I hate spam.
>>> 
>>> 
>>> 
>>> ___
>>> 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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[time-nuts] GPS altitude somewhat wrong?

[Mark Sims]

You have to be careful with a lot of modern GPS receivers.   Many implement 
some sort of "position pinning".   If they do not detect significant movement,  
they either stop updating the coordinates  or heavily filter it...  you do not 
see the actual computed location.  On some receivers you have to move well over 
10 meters before the position un-pins.
--
> CEP(95) of 1.5 meters over 1,000 seconds. 
>   
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Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A (Hal Murray)

[BIll Ezell]

When I interviewed at a large IC mfgr in Santa Clara many years ago, one 
of the questions was basically that - how do you reliably handle startup 
state in a CPU? Of course the correct answer is, you can't with 100% 
certainty. You can make the likelihood small, but there's always some 
obscure case you never thought of. Even hysteresis, clock-count delays, 
etc. have failure modes. Say you hold the reset for 200 msecs, then 
there's a transient. Now your reset circuitry has to be designed so that 
it can reset itself, and you can't guarantee that. And yes, I've used 
the RC hack before.


They also had another trick question, how do you handle a condition 
where you have contention for a resource and one contender has higher 
priority and you want to guarantee it always gets the resource? You of 
course can't. There will always be some, possibly very small, time 
window where you have already made the allocation decision. I think it 
had something to do with multi-port memory or some such.



On 6/9/2016 12:00 PM, time-nuts-requ...@febo.com wrote:

Re: One sure way to kill your FE-5680A or FE-5650A (Hal Murray)
Startup and/or brownout has long been a nasty problem area for digital
designers.

In the old old days, there was typically a R/C delay on the reset pin to a
CPU.  That screwed up when the power supply ramped up slowly enough.  Most
old timers have that merit badge.

Modern CPU chips often have specs like power must be OK for 200 ms before
releasing Reset.  Anything like that will have at least one corresponding
power monitor chip with several supply voltage inputs and the appropriate
delay.



--
Bill Ezell
--
The day Microsoft makes something that doesn't suck
will be the day they make vacuum cleaners.
Or maybe Windows 10.

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Re: [time-nuts] GPS altitude somewhat wrong?

[Van Horn, David]

I'm satisfied that it's reasonably accurate now. 
It is interesting how much elevation can change without really being obvious to 
a person on the ground. 



-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Michael Perrett
Sent: Wednesday, June 8, 2016 5:28 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS altitude somewhat wrong?

I just checked Google Earth and the elevation of your office is 5260', only 
about 24' off of your GPS estimate if that is your location.
Michael

On Wed, Jun 8, 2016 at 1:33 PM, Van Horn, David < 
david.vanh...@backcountryaccess.com> wrote:

>
> I have just installed a Thunderbolt here to get our time and frequency 
> equipment all on the same page.
> As I was looking at the display on Lady Heather, I was noticing that 
> the GPS altitude seems rather wrong.
> We are in Boulder CO, which is nominally 5430' and the antenna is 
> about 20' off the ground.
> The display (near overdetermined position) reads 1589.72991 meters or 
> 5216 and change in feet.
> Altitude is a big deal around here. :)
>
> I suppose 214' isn't that outrageous, but it does bring me to a question:
>
> How accurate is the altitude number really?
>
> Thanks.
>
>
> --
> David VanHorn
> Lead Hardware Engineer
>
> Backcountry Access, Inc.
> 2820 Wilderness Pl, Unit H
> Boulder, CO  80301 USA
> phone: 303-417-1345 x110
> email: david.vanh...@backcountryaccess.com david.vanh...@backcountryaccess.com>
>
> ___
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[time-nuts] London meet-up

[Alan Ambrose]

Following the thread on EEVblog, I volunteered to organise a London *Nuts 
meet-up. See here:

http://www.eevblog.com/forum/metrology/volt-nut-meetings-and-gatherings/

http://www.meetup.com/London-Nuts-Volt-Time-Metrology/

Regards, Alan

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Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

[Clint Jay]

It would seem so bit I don't remember seeing a 'reset'  chip in the 5680.
I'm wondering if there's scope to add one onto the rail that runs the PSD
and 80C320 to keep it in reset.
On 9 Jun 2016 13:00, "Bob Camp"  wrote:

> Hi
>
> Based on the number of different ways there seem to be to corrupt the
> operating software
> in the FE Rb’s …. they seem to have a unique problem. There are a *lot* of
> devices
> using the same basic parts that don’t turn into a brick when this or that
> happens.
>
> Bob
>
> > On Jun 9, 2016, at 4:31 AM, Hal Murray  wrote:
> >
> >
> >> The ATTinys have brownout detectors in them that’s supposed to keep them
> >> from going bonkers during undervolt periods.
> >
> > Startup and/or brownout has long been a nasty problem area for digital
> > designers.
> >
> > In the old old days, there was typically a R/C delay on the reset pin to
> a
> > CPU.  That screwed up when the power supply ramped up slowly enough.
> Most
> > old timers have that merit badge.
> >
> > Modern CPU chips often have specs like power must be OK for 200 ms before
> > releasing Reset.  Anything like that will have at least one corresponding
> > power monitor chip with several supply voltage inputs and the appropriate
> > delay.
> >
> > The brownout side gets ugly when you look at the tolerances.  The
> tolerance
> > on the power monitor subtracts from the power supply tolerances.
> >
> > There is another worm in the can.  How long does it take for your
> oscillator
> > to get going?
> >
> >
> >
> > --
> > These are my opinions.  I hate spam.
> >
> >
> >
> > ___
> > 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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Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

[Bob Camp]

Hi

Based on the number of different ways there seem to be to corrupt the operating 
software
in the FE Rb’s …. they seem to have a unique problem. There are a *lot* of 
devices
using the same basic parts that don’t turn into a brick when this or that 
happens.

Bob

> On Jun 9, 2016, at 4:31 AM, Hal Murray  wrote:
> 
> 
>> The ATTinys have brownout detectors in them that’s supposed to keep them
>> from going bonkers during undervolt periods. 
> 
> Startup and/or brownout has long been a nasty problem area for digital 
> designers.
> 
> In the old old days, there was typically a R/C delay on the reset pin to a 
> CPU.  That screwed up when the power supply ramped up slowly enough.  Most 
> old timers have that merit badge.
> 
> Modern CPU chips often have specs like power must be OK for 200 ms before 
> releasing Reset.  Anything like that will have at least one corresponding 
> power monitor chip with several supply voltage inputs and the appropriate 
> delay.
> 
> The brownout side gets ugly when you look at the tolerances.  The tolerance 
> on the power monitor subtracts from the power supply tolerances.
> 
> There is another worm in the can.  How long does it take for your oscillator 
> to get going?
> 
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] GPS altitude somewhat wrong?

[Hal Murray]

g...@rellim.com said:
> While you are waiting check out the attached scatter plot.  Now THAT is a
> good $25 GPS!  Beats the heck outta any Garmin.  CEP(95) of 1.5 meters over
> 1,000 seconds.

What type of GPS was that?


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] GPS altitude somewhat wrong?

[Angus]

I've had that query before too, but in that case it turned out to be
that by default some receivers/software report Mean Sea Level and
others Height Above Ellipsoid, or both.

Angus.


On Wed, 8 Jun 2016 20:33:58 +, you wrote:

>
>I have just installed a Thunderbolt here to get our time and frequency 
>equipment all on the same page.
>As I was looking at the display on Lady Heather, I was noticing that the GPS 
>altitude seems rather wrong.
>We are in Boulder CO, which is nominally 5430' and the antenna is about 20' 
>off the ground.
>The display (near overdetermined position) reads 1589.72991 meters or 5216 and 
>change in feet.
>Altitude is a big deal around here. :)
>
>I suppose 214' isn't that outrageous, but it does bring me to a question:
>
>How accurate is the altitude number really?
>
>Thanks.
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Re: [time-nuts] One sure way to kill your FE-5680A or FE-5650A

[Hal Murray]

> The ATTinys have brownout detectors in them that’s supposed to keep them
> from going bonkers during undervolt periods. 

Startup and/or brownout has long been a nasty problem area for digital 
designers.

In the old old days, there was typically a R/C delay on the reset pin to a 
CPU.  That screwed up when the power supply ramped up slowly enough.  Most 
old timers have that merit badge.

Modern CPU chips often have specs like power must be OK for 200 ms before 
releasing Reset.  Anything like that will have at least one corresponding 
power monitor chip with several supply voltage inputs and the appropriate 
delay.

The brownout side gets ugly when you look at the tolerances.  The tolerance 
on the power monitor subtracts from the power supply tolerances.

There is another worm in the can.  How long does it take for your oscillator 
to get going?



-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] GPS altitude somewhat wrong?

[Gary E. Miller]

Yo Tom!

On Wed, 8 Jun 2016 19:26:21 -0700
"Tom Van Baak"  wrote:

> From one NW GPS farm to another... I'm willing to help you debug
> yours.

Nothing to debug.  I know if I move the antenna I can do better, but
it does what I need, and it is near the server that needs it. ntpd
caculates precision -22 and the jitter is usually less than 0.5 uSec.
More than good enough for my purposes.  It makes a dandy Stratum 1 
chimer.

And 16 meters is not good at all.  That is 52 feet!  Over just two
hours.  I bet that gets 2x or more worse over 24 hours.  If I cared
about location accuracy I would throw away that GPS. Any modern GPS
should do way better than that.

> > A Garmin 18x reports:
> >Altitude Err:+/- 264 ft 
> 
> Something is terribly wrong with your setup. The Garmin 18x is much,
> much better than this. I know because the 18x was one of the GPS
> receivers I brought along on a recent mobile clock experiment.

Yes, with good antenna placement it can be better, but the 18x also
degrades much quicker than newer GPS when the antenna placement is places
badly.

> in Tucson: http://leapsecond.com/great2016a/2016a-garmin-18x-2.gif

what year is yours?  Looking at mine, I see it is actually an 18, not an
18x, so a 12 year old design .  Worse than the 18x.

> With clear sky view, the peak to peak is under +/- 8 m, and the
> (1-sigma) standard deviation is 3 m. Even at the hotel lobby, with
> obstructed sky view, the (1-sigma) standard deviation stayed under 7
> m. Your 18x number, +/- 264ft (+/- 80 m), is 10x to 25x worse than
> this. It doesn't feel right.

My antenna is between two 2 story houses at ground level against a tall
hill.  It is lucky to get much of a signal at all.  I know it would work
better in aother location, but it needs to be there next to my main
servers.

> Off-list, can you send me a day of NMEA from your 18x? Not gpsd
> output; but the raw serial ascii data from the receiver. I'd like to
> get to the bottom of this. We'll all learn something.

I can get you pseudo NMEA, the Garmins work much better in binary mode.
When they work in binary mode. :-)

I'll start to grab that now.  I'll have a 12 hour scatter plot in
the morning.

While you are waiting check out the attached scatter plot.  Now THAT
is a good $25 GPS!  Beats the heck outta any Garmin.  CEP(95) of 1.5
meters over 1,000 seconds.

RGDS
GARY
---
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com  Tel:+1 541 382 8588


pgpZjysP8lH0L.pgp
Description: OpenPGP digital signature
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