Re: [time-nuts] HP10811 Oscillator Thermal Fuse

[Van Horn, David]

The original article was from Kodiak consulting.  Good thing I saved a copy. 
Thanks for the link to this one. 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Donald E. Pauly
Sent: Thursday, May 11, 2017 6:57 PM
To: time-nuts; Donald E. Pauly
Subject: [time-nuts] HP10811 Oscillator Thermal Fuse

https://www.febo.com/pipermail/time-nuts/2017-May/date.html

While I find traces of your article quoted, it seems to have vanished.
It lead me to this interesting article of 16 pages on electronic fires by a 
fire investigator.  There is a lot here for designers when it comes to 
preventing fires from your products.  I would never have dreamed of some of the 
ways that fires can start.

http://dri.org/docs/default-source/dri-online/course-materials/2016/fire-science/08-dangerous-things-come-in-small-packages.pdf


πθ°μΩω±√·Γλ
WB0KVV

-- Forwarded message --
From: Van Horn, David 
Date: Thu, May 11, 2017 at 4:31 PM
Subject: Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse
To: Discussion of precise time and frequency measurement 


There's an excellent article out there on the web called "Low Voltage, the 
incompetent ignition source"  I highly recommend a read.
I dealt with a case like this a couple years ago.  Failed fet in an H bridge 
caused a fault which the brick SMPS picked up as a short, and went into 
"hiccup" mode on.
The energy delivered in "hiccup" mode was about 1W average, and that was 
enough, after several hours, to cause ignition and sustained flame on the PCB.

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Re: [time-nuts] Surplus Lucent RFTG-m-II units in rack shelf

[Gregory Beat]

As noted by Bob Camp, this Lucent pair has a rubidium standard and OCXO.
Since I posted (15 hours ago), he has sold 18 units.

So, would love to hear reports (good, bad, time ugly) next week.

Greg

> I noticed this surplus Lucent KS-24019 L108 / L109 item on eBay, 
> auction # 132186030112, by a01mhowa , based in South Carolina.
> 



Sent from iPad Air
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Re: [time-nuts] time.gov

[Jerry Hancock]

Since the application takes into account the network speed, maybe there is a 
cacheing issue initially that is then corrected when you refresh the page?  
It’s no longer doing it now but was for several hours earlier today.  

Strange.
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[time-nuts] TruePosition GPSDO performance

[Mark Sims]

Ok,  I dusted the TruePosition OCXO with some freeze spray.   Not pretty 
picture attached...  it took around 6 minutes to stabilize.  I used just enough 
spray to lightly frost the can.  It would probably help to shield the board 
from drafts,  but probably not wrap it in a polar parka.

It did put the unit into holdover.   Other holdovers I've seen had a very 
stable temperature sensor reading.  No air conditioning on and a stable room 
temperature.___
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Re: [time-nuts] time.gov

[David G. McGaw]

Just tried it, came up 4 sec. slow.  Refreshed the page and it was correct.

David N1HAC


On 5/11/17 7:52 PM, Jerry Hancock wrote:

I checked it on two different computers and again just now, all were counting 
5+ seconds slow.  I then downloaded their flash app which as an option I never 
had to do and that was correct.  Both of the apps claim to be adjusted for 
network delay.

This was around 14:00Pacific.  I just checked again and both apps are now 
correct.  I’ll have to dig into the issue.



On May 11, 2017, at 3:09 PM, Donald E. Pauly  wrote:

https://www.febo.com/pipermail/time-nuts/2017-May/date.html

About 10 years ago, I checked my WWVB time code receiver that I built
against time.gov and it was within 0.1 seconds.  That was as close as
the eyeball can tell.  You report a huge error and if confirmed, you
should complain.  I would double check against WWV since WWVB is now
worthless for time comparison.  That webpage is supposed to be
compensated for network delay within 0.1 second.

Just now at 15:00:00 MST I checked my phone with time.gov on wireless
versus a full size computer also on wireless.  I momentarily saw the
phone 65 seconds ahead of the computer.  After hitting refresh and
going off wireless and directly to my carrier, the phone matched the
computer.  I had a witness but cannot get the problem to reappear.  I
don't know exactly why the problem went away.  Some servers may cache
web pages so refresh may be necessary.

πθ°μΩω±√·Γλ
WB0KVV

-- Forwarded message --
From: Jerry Hancock 
Date: Thu, May 11, 2017 at 2:36 PM
Subject: [time-nuts] time.gov
To: Discussion of precise time and frequency measurement 


I went to time.gov today as I was sitting away from my lab when a new
watch arrived.  Finally got the 25yr watch from the company that laid
me off a week later…

Anyway, I set the seconds rollover to 00 when time.gov reset and then
walked down to my lab and noticed the watch is now 6 seconds slow.  So
I checked again with another computer, same problem, www.time.gov is 6
seconds slow.  Never say this happen, usually it is right on the money
give or take about .2 seconds.

Jerry
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[time-nuts] A good GPS-Receiver with 1PPS output...

[Mark Sims]

https://www.tindie.com/products/nsayer/skytraq-venus838lpx-t-timing-gps-module-breakout/

-

>  Can't find this on Tindie???
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Re: [time-nuts] TruePosition GPS Receiver firmware

[Tom Miller]

Has anyone figured out what the two small push buttons do?


- Original Message - 
From: "Ben Hall" 

To: 
Sent: Monday, May 08, 2017 7:30 PM
Subject: Re: [time-nuts] TruePosition GPS Receiver firmware



On 5/8/2017 4:45 PM, Mark Sims wrote:
Anyway, Heather is now doing a pretty good job of working with it. Oh, 
and the seller jacked up the price by $10.


Received one bare board and one LMU today.  The bare board is up and 
running as I type, happily doing a survey.  About 200 ma draw at 14.5 VDC. 
She was reporting a position somewhere in New Jersey when I first powered 
it up.


I'll bet the seller saw a sudden increase in demand and decided to raise 
the price.  Yes - the whole LMU is now cheaper by a few bucks including 
shipping, at least to my house here.


I don't have it on Lady Heather yet but plan to do that soon.  Is the 
version hosted here  have the 
TruePosition code in it?


thanks much,
ben







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Re: [time-nuts] A good GPS-Receiver with 1PPS output...

[Nick Sayer via time-nuts]

https://www.tindie.com/products/nsayer/skytraq-venus838lpx-t-timing-gps-module-breakout/
 


> On May 11, 2017, at 5:36 PM, djl  wrote:
> 
> Can't find this on Tindie???
> 
> On 2017-05-10 09:03, Mark Sims wrote:
>> The GPS with the lowest PPS jitter/sawtooth is the Venus timing
>> receiver... around 6 ns.   Nick Sayer sells one on Tindie for $50.  It
>> is mounted on a board that has the same pinouts as the Adafruit
>> Ultimate GPS.  Also Navspark sells one for more $.
>> Lady Heather talks to the Venus receivers.
>> ___
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> 
> -- 
> Dr. Don Latham
> PO Box 404, Frenchtown, MT, 59834
> VOX: 406-626-4304
> 
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[time-nuts] HP10811 Oscillator Thermal Fuse

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-May/date.html

While I find traces of your article quoted, it seems to have vanished.
It lead me to this interesting article of 16 pages on electronic fires
by a fire investigator.  There is a lot here for designers when it
comes to preventing fires from your products.  I would never have
dreamed of some of the ways that fires can start.

http://dri.org/docs/default-source/dri-online/course-materials/2016/fire-science/08-dangerous-things-come-in-small-packages.pdf


πθ°μΩω±√·Γλ
WB0KVV

-- Forwarded message --
From: Van Horn, David 
Date: Thu, May 11, 2017 at 4:31 PM
Subject: Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse
To: Discussion of precise time and frequency measurement 


There's an excellent article out there on the web called "Low Voltage,
the incompetent ignition source"  I highly recommend a read.
I dealt with a case like this a couple years ago.  Failed fet in an H
bridge caused a fault which the brick SMPS picked up as a short, and
went into "hiccup" mode on.
The energy delivered in "hiccup" mode was about 1W average, and that
was enough, after several hours, to cause ignition and sustained flame
on the PCB.

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Re: [time-nuts] A good GPS-Receiver with 1PPS output...

[djl]

Can't find this on Tindie???

On 2017-05-10 09:03, Mark Sims wrote:

The GPS with the lowest PPS jitter/sawtooth is the Venus timing
receiver... around 6 ns.   Nick Sayer sells one on Tindie for $50.  It
is mounted on a board that has the same pinouts as the Adafruit
Ultimate GPS.  Also Navspark sells one for more $.

Lady Heather talks to the Venus receivers.
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--
Dr. Don Latham
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304

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

[Jeremy Nichols]

I had a vaguely similar situation with a pressure switch for the pump in my
home's water supply. The electrical contacts in the pressure switch have to
handle about 10 Amps at 250 Volts (our line voltage is on the high side).
Over the years, the contacts burn and become "ohmic" contacts, gradually
increasing in resistance. Early one morning the contacts finally got so
resistive they couldn't pass enough current to start the pump. Since the
water pressure never came up, the switch never shut off. It got hotter and
hotter and finally burst into flame. I found out about it at 4:00 AM when a
smoke alarm woke me. An extinguisher was sufficient to dowse the flames
although the local fire fighters were called as a precaution, me being
still half asleep. When I replaced the pressure switch, I added a thermal
fuse as protection should that problem ever recur.

Jeremy



On Thu, May 11, 2017 at 4:04 PM Donald E. Pauly 
wrote:

> https://www.febo.com/pipermail/time-nuts/2017-May/date.html
>
> This is the third report of an open thermistor which would have
> resulted in a fire in an HP10811 oven.  There are a dozen other
> problems that could cause such a fire.  See
> http://gonascent.com/papers/hp/hp10811/thermal.jpg .  The leads are
> long enough that they can be soldered quickly without a heat sink if
> the socket is to be replaced for better reliability.  A hemostat can
> also be used to heatsink the leads one at a time.  We have the 108° C
> fuse which is prone to nuisance blows.  HP has superceded it with a
> 125° C version.  Panasonic seems to make a direct replacement.  It is
> stocked by Digikey for under a dollar.  I can find no reports of a
> nuisance blow of the 125° version of the thermal fuse in a HP10811.
> All nuisance blows seem to be in the 108° version.
>
> In the 1970s, many consumer electronic products with 60 cps power
> transformers had a thermal fuse inside them.  I bought a Sony real to
> real stereo tape deck which was not working with that problem.  It was
> a nuisance blow since no problems existed in the tape deck.  I
> installed a fine gauge piece of solder since the fuse was close to
> 180° C.  I used it for over two years with no problems.
>
> Later model switching power supplies have windings of several volts
> per turn.  Shorts in these transformers will blow the fuse or destroy
> the switching transistors.  A 60 cps transformer operates at a small
> fraction of a volt per turn. A few shorted turns in a will not draw an
> excessive primary current but merely causes a hot spot.  The hot spot
> will grow as additional turns short.  Line current will not be greatly
> excessive even as the transformer heats up.  It can catch fire well
> before the fuse blows.
>
> I saw a living room that caught fire because of a 60 cps transformer
> in a stereo receiver.  The line breaker never tripped.  But for the
> grace of G-d, the house would have burnt down.  A thermal fuse in the
> transformer would have prevented several thousand dollars of damage.
> That would have paid for over a thousand thermal fuses.
>
> πθ°μΩω±√·Γλ
> WB0KVV
>
>  Forwarded message --
> From: David G. McGaw 
> Date: Wed, May 10, 2017 at 8:20 PM
> Subject: Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse
> To: Discussion of precise time and frequency measurement <
> time-nuts@febo.com>
>
> I too have had a fuse open up due to a failed thermistor in a HP10811.
>
> David N1HAC
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-- 
Sent from Gmail Mobile
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[time-nuts] Fwd: time.gov

[Donald E. Pauly]

Be sure to post your result. Five years ago I regularly checked my
Casio LED watch which was holding 0.3 seconds per week.  It always
worked properly.   Perhaps we should report this to Trump so he can
fire the head of NIST.

-- Forwarded message --
From: Jerry Hancock 
Date: Thu, May 11, 2017 at 4:52 PM
Subject: Re: [time-nuts]  time.gov
To: Discussion of precise time and frequency measurement 
Cc: "Donald E. Pauly" 


I checked it on two different computers and again just now, all were
counting 5+ seconds slow.  I then downloaded their flash app which as
an option I never had to do and that was correct.  Both of the apps
claim to be adjusted for network delay.

This was around 14:00Pacific.  I just checked again and both apps are
now correct.  I’ll have to dig into the issue.


> On May 11, 2017, at 3:09 PM, Donald E. Pauly  wrote:
>
> https://www.febo.com/pipermail/time-nuts/2017-May/date.html
>
> About 10 years ago, I checked my WWVB time code receiver that I built
> against time.gov and it was within 0.1 seconds.  That was as close as
> the eyeball can tell.  You report a huge error and if confirmed, you
> should complain.  I would double check against WWV since WWVB is now
> worthless for time comparison.  That webpage is supposed to be
> compensated for network delay within 0.1 second.
>
> Just now at 15:00:00 MST I checked my phone with time.gov on wireless
> versus a full size computer also on wireless.  I momentarily saw the
> phone 65 seconds ahead of the computer.  After hitting refresh and
> going off wireless and directly to my carrier, the phone matched the
> computer.  I had a witness but cannot get the problem to reappear.  I
> don't know exactly why the problem went away.  Some servers may cache
> web pages so refresh may be necessary.
>
> πθ°μΩω±√·Γλ
> WB0KVV
>
> -- Forwarded message --
> From: Jerry Hancock 
> Date: Thu, May 11, 2017 at 2:36 PM
> Subject: [time-nuts] time.gov
> To: Discussion of precise time and frequency measurement 
>
>
> I went to time.gov today as I was sitting away from my lab when a new
> watch arrived.  Finally got the 25yr watch from the company that laid
> me off a week later…
>
> Anyway, I set the seconds rollover to 00 when time.gov reset and then
> walked down to my lab and noticed the watch is now 6 seconds slow.  So
> I checked again with another computer, same problem, www.time.gov is 6
> seconds slow.  Never say this happen, usually it is right on the money
> give or take about .2 seconds.
>
> Jerry
> ___
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Re: [time-nuts] time.gov

[Jerry Hancock]

I checked it on two different computers and again just now, all were counting 
5+ seconds slow.  I then downloaded their flash app which as an option I never 
had to do and that was correct.  Both of the apps claim to be adjusted for 
network delay. 

This was around 14:00Pacific.  I just checked again and both apps are now 
correct.  I’ll have to dig into the issue.


> On May 11, 2017, at 3:09 PM, Donald E. Pauly  wrote:
> 
> https://www.febo.com/pipermail/time-nuts/2017-May/date.html
> 
> About 10 years ago, I checked my WWVB time code receiver that I built
> against time.gov and it was within 0.1 seconds.  That was as close as
> the eyeball can tell.  You report a huge error and if confirmed, you
> should complain.  I would double check against WWV since WWVB is now
> worthless for time comparison.  That webpage is supposed to be
> compensated for network delay within 0.1 second.
> 
> Just now at 15:00:00 MST I checked my phone with time.gov on wireless
> versus a full size computer also on wireless.  I momentarily saw the
> phone 65 seconds ahead of the computer.  After hitting refresh and
> going off wireless and directly to my carrier, the phone matched the
> computer.  I had a witness but cannot get the problem to reappear.  I
> don't know exactly why the problem went away.  Some servers may cache
> web pages so refresh may be necessary.
> 
> πθ°μΩω±√·Γλ
> WB0KVV
> 
> -- Forwarded message --
> From: Jerry Hancock 
> Date: Thu, May 11, 2017 at 2:36 PM
> Subject: [time-nuts] time.gov
> To: Discussion of precise time and frequency measurement 
> 
> 
> I went to time.gov today as I was sitting away from my lab when a new
> watch arrived.  Finally got the 25yr watch from the company that laid
> me off a week later…
> 
> Anyway, I set the seconds rollover to 00 when time.gov reset and then
> walked down to my lab and noticed the watch is now 6 seconds slow.  So
> I checked again with another computer, same problem, www.time.gov is 6
> seconds slow.  Never say this happen, usually it is right on the money
> give or take about .2 seconds.
> 
> Jerry
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Re: [time-nuts] HP10811 Oscillator Thermal Fuse

[Bob kb8tq]

Hi

The ones that people decided are dead quite literally went into the trash can 
long long
ago. They never made it into the eBay era. The warranty on the gear was short 
enough
that nobody thought to send them back. The days of “tear into it and fix it” at 
the component
level were over *long* before the 10811 came out. Anybody servicing this gear 
was on
a strict “sway modules and get it running” set of orders. 

Bob

> On May 11, 2017, at 7:42 PM, Donald E. Pauly  wrote:
> 
> https://www.febo.com/pipermail/time-nuts/2017-May/date.html
> 
> These oscillators sold for $800 in 1985 or so.  They are on eBay all
> working for $250 or more.  Where are all the ones with blown thermal
> fuses for $25?  I want to buy.  It would be interesting to have the HP
> warranty data for nuisance blows.  The three reported fire preventions
> would have paid for the labor on all of the reported nuisance blows.
> This is not to excuse the HP design error of picking a thermal fuse
> temperature too close to the operating temperature.  Smoke damage
> could do thousands of dollars of damage to a HP5061B or and expensive
> microwave instrument.
> 
> πθ°μΩω±√·Γλ
> WB0KVV
> 
> -- Forwarded message --
> From: Bob kb8tq 
> Date: Thu, May 11, 2017 at 4:28 PM
> Subject: Re: [time-nuts] HP10811 Oscillator Thermal Fuse
> To: Discussion of precise time and frequency measurement 
> 
> Hi
> 
> A bit in jest:… that compares to 3,957 incidences of open fuses that
> had nothing to do with
> a thermal runaway. Of those, the majority 3,721 resulted in the 10811
> being tossed
> in the garbage as “another junker”……(yes, those are estimates, but I’d
> bet they are close
> based on the number of 10811’s made and how flakey those fuses are).
> 
> Bob
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[time-nuts] HP10811 Oscillator Thermal Fuse

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-May/date.html

These oscillators sold for $800 in 1985 or so.  They are on eBay all
working for $250 or more.  Where are all the ones with blown thermal
fuses for $25?  I want to buy.  It would be interesting to have the HP
warranty data for nuisance blows.  The three reported fire preventions
would have paid for the labor on all of the reported nuisance blows.
This is not to excuse the HP design error of picking a thermal fuse
temperature too close to the operating temperature.  Smoke damage
could do thousands of dollars of damage to a HP5061B or and expensive
microwave instrument.

πθ°μΩω±√·Γλ
WB0KVV

-- Forwarded message --
From: Bob kb8tq 
Date: Thu, May 11, 2017 at 4:28 PM
Subject: Re: [time-nuts] HP10811 Oscillator Thermal Fuse
To: Discussion of precise time and frequency measurement 

Hi

A bit in jest:… that compares to 3,957 incidences of open fuses that
had nothing to do with
a thermal runaway. Of those, the majority 3,721 resulted in the 10811
being tossed
in the garbage as “another junker”……(yes, those are estimates, but I’d
bet they are close
based on the number of 10811’s made and how flakey those fuses are).

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

[Van Horn, David]

There's an excellent article out there on the web called "Low Voltage, the 
incompetent ignition source"  I highly recommend a read. 
I dealt with a case like this a couple years ago.  Failed fet in an H bridge 
caused a fault which the brick SMPS picked up as a short, and went into 
"hiccup" mode on.
The energy delivered in "hiccup" mode was about 1W average, and that was 
enough, after several hours, to cause ignition and sustained flame on the PCB.

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Re: [time-nuts] HP10811 Oscillator Thermal Fuse

[Bob kb8tq]

Hi

A bit in jest:… that compares to 3,957 incidences of open fuses that had 
nothing to do with
a thermal runaway. Of those, the majority 3,721 resulted in the 10811 being 
tossed
in the garbage as “another junker”……(yes, those are estimates, but I’d bet they 
are close
based on the number of 10811’s made and how flakey those fuses are). 

Bob

> On May 11, 2017, at 7:04 PM, Donald E. Pauly  wrote:
> 
> https://www.febo.com/pipermail/time-nuts/2017-May/date.html
> 
> This is the third report of an open thermistor which would have
> resulted in a fire in an HP10811 oven.  There are a dozen other
> problems that could cause such a fire.  See
> http://gonascent.com/papers/hp/hp10811/thermal.jpg .  The leads are
> long enough that they can be soldered quickly without a heat sink if
> the socket is to be replaced for better reliability.  A hemostat can
> also be used to heatsink the leads one at a time.  We have the 108° C
> fuse which is prone to nuisance blows.  HP has superceded it with a
> 125° C version.  Panasonic seems to make a direct replacement.  It is
> stocked by Digikey for under a dollar.  I can find no reports of a
> nuisance blow of the 125° version of the thermal fuse in a HP10811.
> All nuisance blows seem to be in the 108° version.
> 
> In the 1970s, many consumer electronic products with 60 cps power
> transformers had a thermal fuse inside them.  I bought a Sony real to
> real stereo tape deck which was not working with that problem.  It was
> a nuisance blow since no problems existed in the tape deck.  I
> installed a fine gauge piece of solder since the fuse was close to
> 180° C.  I used it for over two years with no problems.
> 
> Later model switching power supplies have windings of several volts
> per turn.  Shorts in these transformers will blow the fuse or destroy
> the switching transistors.  A 60 cps transformer operates at a small
> fraction of a volt per turn. A few shorted turns in a will not draw an
> excessive primary current but merely causes a hot spot.  The hot spot
> will grow as additional turns short.  Line current will not be greatly
> excessive even as the transformer heats up.  It can catch fire well
> before the fuse blows.
> 
> I saw a living room that caught fire because of a 60 cps transformer
> in a stereo receiver.  The line breaker never tripped.  But for the
> grace of G-d, the house would have burnt down.  A thermal fuse in the
> transformer would have prevented several thousand dollars of damage.
> That would have paid for over a thousand thermal fuses.
> 
> πθ°μΩω±√·Γλ
> WB0KVV
> 
>  Forwarded message --
> From: David G. McGaw 
> Date: Wed, May 10, 2017 at 8:20 PM
> Subject: Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse
> To: Discussion of precise time and frequency measurement 
> 
> I too have had a fuse open up due to a failed thermistor in a HP10811.
> 
> David N1HAC
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Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-May/date.html

This is the third report of an open thermistor which would have
resulted in a fire in an HP10811 oven.  There are a dozen other
problems that could cause such a fire.  See
http://gonascent.com/papers/hp/hp10811/thermal.jpg .  The leads are
long enough that they can be soldered quickly without a heat sink if
the socket is to be replaced for better reliability.  A hemostat can
also be used to heatsink the leads one at a time.  We have the 108° C
fuse which is prone to nuisance blows.  HP has superceded it with a
125° C version.  Panasonic seems to make a direct replacement.  It is
stocked by Digikey for under a dollar.  I can find no reports of a
nuisance blow of the 125° version of the thermal fuse in a HP10811.
All nuisance blows seem to be in the 108° version.

In the 1970s, many consumer electronic products with 60 cps power
transformers had a thermal fuse inside them.  I bought a Sony real to
real stereo tape deck which was not working with that problem.  It was
a nuisance blow since no problems existed in the tape deck.  I
installed a fine gauge piece of solder since the fuse was close to
180° C.  I used it for over two years with no problems.

Later model switching power supplies have windings of several volts
per turn.  Shorts in these transformers will blow the fuse or destroy
the switching transistors.  A 60 cps transformer operates at a small
fraction of a volt per turn. A few shorted turns in a will not draw an
excessive primary current but merely causes a hot spot.  The hot spot
will grow as additional turns short.  Line current will not be greatly
excessive even as the transformer heats up.  It can catch fire well
before the fuse blows.

I saw a living room that caught fire because of a 60 cps transformer
in a stereo receiver.  The line breaker never tripped.  But for the
grace of G-d, the house would have burnt down.  A thermal fuse in the
transformer would have prevented several thousand dollars of damage.
That would have paid for over a thousand thermal fuses.

πθ°μΩω±√·Γλ
WB0KVV

 Forwarded message --
From: David G. McGaw 
Date: Wed, May 10, 2017 at 8:20 PM
Subject: Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse
To: Discussion of precise time and frequency measurement 

I too have had a fuse open up due to a failed thermistor in a HP10811.

David N1HAC
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Re: [time-nuts] E1938 info regarding LEDs, push button switch and EFC voltage notation

[Azelio Boriani]

You can find schematics and various info here:




On Thu, May 11, 2017 at 3:47 PM, James Robbins  wrote:
> 1.  I have just acquired an E1938 and powered it up.  It seems to work.   I
> see that it has 4 blinking board LEDs (green, red, yellow, yellow) and a
> pushbutton switch at the end of the board opposite to the DB25 connector.
> Can anyone point me to either the schematic for the board or what these LEDs
> and pushbutton show or do?
>
>
>
> 2.  Also, there is an "EFC" voltage ("3.69v") marked in magic marker on top
> of the can.  Can anyone point me to where I can learn what, if anything,
> this voltage notation should be used for?
>
>
>
> Many thanks.
>
>
>
> Jim Robbins
>
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[time-nuts] time.gov

[Donald E. Pauly]

https://www.febo.com/pipermail/time-nuts/2017-May/date.html

About 10 years ago, I checked my WWVB time code receiver that I built
against time.gov and it was within 0.1 seconds.  That was as close as
the eyeball can tell.  You report a huge error and if confirmed, you
should complain.  I would double check against WWV since WWVB is now
worthless for time comparison.  That webpage is supposed to be
compensated for network delay within 0.1 second.

Just now at 15:00:00 MST I checked my phone with time.gov on wireless
versus a full size computer also on wireless.  I momentarily saw the
phone 65 seconds ahead of the computer.  After hitting refresh and
going off wireless and directly to my carrier, the phone matched the
computer.  I had a witness but cannot get the problem to reappear.  I
don't know exactly why the problem went away.  Some servers may cache
web pages so refresh may be necessary.

πθ°μΩω±√·Γλ
WB0KVV

-- Forwarded message --
From: Jerry Hancock 
Date: Thu, May 11, 2017 at 2:36 PM
Subject: [time-nuts] time.gov
To: Discussion of precise time and frequency measurement 


I went to time.gov today as I was sitting away from my lab when a new
watch arrived.  Finally got the 25yr watch from the company that laid
me off a week later…

Anyway, I set the seconds rollover to 00 when time.gov reset and then
walked down to my lab and noticed the watch is now 6 seconds slow.  So
I checked again with another computer, same problem, www.time.gov is 6
seconds slow.  Never say this happen, usually it is right on the money
give or take about .2 seconds.

Jerry
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[time-nuts] time.gov

[Jerry Hancock]

I went to time.gov today as I was sitting away from my lab when a new watch 
arrived.  Finally got the 25yr watch from the company that laid me off a week 
later…

Anyway, I set the seconds rollover to 00 when time.gov reset and then walked 
down to my lab and noticed the watch is now 6 seconds slow.  So I checked again 
with another computer, same problem, www.time.gov is 6 seconds slow.  Never say 
this happen, usually it is right on the money give or take about .2 seconds.

Jerry
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Re: [time-nuts] TruePosition GPSDO performance

[Bob kb8tq]

Hi

The small OCXO in the TruePosition probably will do better with a beach towel 
tossed over the unit. It’s going to
be pretty sensitive to drafts ….There are teardown pictures in the archives of 
the OCXO. Not much insulation in 
one of them at all.

Bob

> On May 11, 2017, at 4:06 PM, Mark Sims  wrote:
> 
> I ran a test of the TruePosition 1PPS signal performance using a TAPR TICC.  
> The TICC was clocked by a HP-5071A.  The TICC was in time interval mode with 
> the Zyfer 1PPS on channel A and the 5071A 1PPS on channel B.   
> 
> The TruePosition had been powered up for a couple of days.   Values below tau 
> around 30 seconds are probably better, but the TICC resolution is the 
> limiting factor.
> 
> The blue plot is frequency deviation of the 1PPS (1Hz)  signal scaled to 10 
> MHz from a nominal.value of 10 MHz.  My TADD2-mini dividers were in use 
> elsewhere, so I could not measure the actual 10 MHz output.
> 
> It looks like the TruePosition ADEVs are up to around an  order of magnitude 
> worse than the Zyfer Nanosync (but the TruePosition costs 5X less).  
> 
> I have noticed that the TruePosition likes to occasionally go into one of its 
> holdover modes despite tracking lots of sats with good signal levels.  The 
> holdovers tend to last a few minutes.  There were not any holdovers in this 
> run.  They don't seem to greatly affect the outputs.
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[time-nuts] TruePosition GPSDO performance

[Mark Sims]

I ran a test of the TruePosition 1PPS signal performance using a TAPR TICC.  
The TICC was clocked by a HP-5071A.  The TICC was in time interval mode with 
the Zyfer 1PPS on channel A and the 5071A 1PPS on channel B.   

The TruePosition had been powered up for a couple of days.   Values below tau 
around 30 seconds are probably better, but the TICC resolution is the limiting 
factor.

The blue plot is frequency deviation of the 1PPS (1Hz)  signal scaled to 10 MHz 
from a nominal.value of 10 MHz.  My TADD2-mini dividers were in use elsewhere, 
so I could not measure the actual 10 MHz output.

It looks like the TruePosition ADEVs are up to around an  order of magnitude 
worse than the Zyfer Nanosync (but the TruePosition costs 5X less).  

I have noticed that the TruePosition likes to occasionally go into one of its 
holdover modes despite tracking lots of sats with good signal levels.  The 
holdovers tend to last a few minutes.  There were not any holdovers in this 
run.  They don't seem to greatly affect the outputs.
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Re: [time-nuts] Anthorn eLoran

[paul swed]

Dave that may have been me. Yes there is other timing data on the signal.
Thats what helps the receiver do a better job of understanding frequency
and time.
The old austrons and such do not process the bits. But if I had to guess
its easy enough to actually get them out to experiment with.
Regards
Paul
WB8TSL

On Thu, May 11, 2017 at 8:36 AM, Dave B via time-nuts 
wrote:

> Didn’t someone say a while back, that there appeared to be "other data"
> present on the transmission, but didn't know what it was, or used
> for...   Or did I imagine it.?
>
> Maybe that's why they keep it going?
>
> 73.
>
> Dave G0WBX.
>
>
> On 11/05/17 05:15, time-nuts-requ...@febo.com wrote:
> > Message: 5
> > Date: Wed, 10 May 2017 21:22:27 +0100
> > From: "Alan Melia" 
> > To: "Discussion of precise time and frequency measurement"
> >   
> > Subject: Re: [time-nuts] Anthorn eLoran
> > Message-ID: <74167B6989E2494EA086A2F1382A50E1@gnat>
> > Content-Type: text/plain; format=flowed; charset="utf-8";
> >   reply-type=original
> >
> > Hi Peter
> > Ah that sounds more like it. Aerial maintenaance shuts down the whole
> site
> > these dats including MSF.  There is really no reason for them to keep it
> > running but I think Trinity House are paying the bill. It cannot be used
> for
> > nav without Lessay and the output from Sylt, So I muse that they are
> keeping
> > it powered up because the equipment is quite old now (1990s vintage, the
> > unused kit destined for Loop Head in Ireland) and if the leave it off for
> > any length of time it just wont start again :-))  We all know that
> syndrome
> > !
> >
> > I dont know if this is correct but I got the feeling it was not running
> > anything like full power??
> >
> > Alan
> > G3NYK
>
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Re: [time-nuts] HP10811 Oscillator Thermal Fuse

[Richard (Rick) Karlquist]

On 5/11/2017 4:25 AM, Bob kb8tq wrote:


Ultimately it all came to no good. The energy conservation rules simply took 
over. Shutting
down everything during off hours became the way a lot of outfits did things. 
Don’t turn off all


A couple of comments on this, probably no surprise to many
time nuts.  All or most HP instruments with 10811's keep the
oven energized even if the instrument is turned "off".
Many classic HP instruments used power transformers for
power supplies.  The secondaries were regulated by a
combination of switches and linear regulators.  The
power module was mounted on the rear panel, along
with the transformer, to help get rid of the heat without
heating up the box too much.  The dilemma was that you
had to choose between four bad alternatives:

1.  Put the power switch on the rear panel.  This is
inconvenient for the user, especially if the unit is
racked.

2.  Put the power switch on the front panel.  This
entails running wiring with all the safety approvals
up to the front panel and back to the rear panel.
I don't know of this ever being done at HP.

3.  Have a button on the front panel that actuates
a long plastic shaft the goes to the real switch at
the back.  Works, but quite a hassle.

4.  What was usually done:  leave the power transformer
primary connected all the time and switch the secondaries.

The HP transformer shop would often scrimp on the amount
of iron in the transformer, which would increase the
core loss.  Their idea of good engineering practice was
to allow the loss to heat the transformer up 10's of
degrees.  Note that core loss is independent of how
much power you are drawing from the secondaries, if any.

So in the overall scheme of things, the 10811 is small
potatoes.  Once it is warmed up, it doesn't draw much
power.

Rick N6RK
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Re: [time-nuts] TAPR GPS Kits

[Steve - Home]

Larry,
No missed emails on your part. I'm waiting on confirmation of the shipment with 
final shipping cost before I calculate a firm price. Hope to have confirmation 
today or tomorrow latest. 

Steve




> On May 11, 2017, at 11:33 AM, Larry McDavid  wrote:
> 
> Steve, did I miss an email confirming the price of these plates? Did you get 
> a confirmation of your order of the plates?
> 
> I have not paid you yet so please tell me if I missed your email that would 
> trigger my payment.
> 
> Larry
> 
> 
>> On 5/5/2017 10:44 AM, Steve - Home wrote:
>> All,
>> 
>> I've logged all the orders and received a final quote from P-M. We had a 
>> final quantity of 130, of which 116 were ordered drilled. The cost works out:
>> 6.35 per plate, shipping and taxes .80 per plate, total of 7.10 per plate. 
>> If you choose to pay via PayPal versus check or money order, the fees are 
>> .21 per plate plus .30 per order. Please don't pay until I get confirmation 
>> the order has been shipped and charged to my credit card. I'll let you know 
>> when that happens.
>> The plates will be shipped in one box to the machinist who has volunteered 
>> his time and CNC equipment to the group. We ask that you pay for the 
>> shipping from him to you and he will be in touch when the plates are ready 
>> to ship.
>> 
>> Thanks,
>> 
>> Steve
>> WB0DBS
> 
> 
> -- 
> Best wishes,
> 
> Larry McDavid W6FUB
> Anaheim, California  (SE of Los Angeles, near Disneyland)
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Re: [time-nuts] TAPR GPS Kits

[Larry McDavid]

Steve, did I miss an email confirming the price of these plates? Did you 
get a confirmation of your order of the plates?


I have not paid you yet so please tell me if I missed your email that 
would trigger my payment.


Larry


On 5/5/2017 10:44 AM, Steve - Home wrote:

All,

I've logged all the orders and received a final quote from P-M. We had a final 
quantity of 130, of which 116 were ordered drilled. The cost works out:
6.35 per plate, shipping and taxes .80 per plate, total of 7.10 per plate. If 
you choose to pay via PayPal versus check or money order, the fees are .21 per 
plate plus .30 per order. Please don't pay until I get confirmation the order 
has been shipped and charged to my credit card. I'll let you know when that 
happens.
The plates will be shipped in one box to the machinist who has volunteered his 
time and CNC equipment to the group. We ask that you pay for the shipping from 
him to you and he will be in touch when the plates are ready to ship.

Thanks,

Steve
WB0DBS



--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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[time-nuts] Surplus Lucent RFTG-m-II units in rack shelf (eBay)

[Gregory Beat]

I noticed this surplus Lucent item on eBay, auction # 132186030112
by a01mhowa , based in South Carolina.

KS-24019 L108 / L109 rack unit appears to be commercial CDMA site pulls with 
interconnection cables.
Seller states he has more than 10 units.

greg, w9gb

Sent from iPad Air
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Re: [time-nuts] HP10811 Oscillator Thermal Fuse

[Bob kb8tq]

Hi


> On May 11, 2017, at 11:22 AM, Bill Hawkins  wrote:
> 
> Labs could have used a common gas heater for the crystal ovens, with a
> bit of rewiring.
> 
> No fire hazard there - you've got a chimney. Also, flame safety is well
> developed for gas heaters.
> 
> Would have required throttling gas flow control.

All of which would have required a OCXO designed to work that way. If you ever 
come across one, post pictures.

Bob

> 
> Bill Hawkins
> 
> Another possibility is circulating hot water.
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob
> kb8tq
> Sent: Thursday, May 11, 2017 6:25 AM
> 
> 
> Ultimately it all came to no good. The energy conservation rules simply
> took over. Shutting down everything during off hours became the way a
> lot of outfits did things. Don't turn off all your bench gear and you
> get a nasty note. I am not aware of full power being dropped during off
> hours. That tends to take out things you really do not want to shut down
> (fire sensors .). 
> 
> 
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Re: [time-nuts] HP10811 Oscillator Thermal Fuse

[Bill Hawkins]

Labs could have used a common gas heater for the crystal ovens, with a
bit of rewiring.

No fire hazard there - you've got a chimney. Also, flame safety is well
developed for gas heaters.

Would have required throttling gas flow control.

Bill Hawkins

Another possibility is circulating hot water.

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob
kb8tq
Sent: Thursday, May 11, 2017 6:25 AM


Ultimately it all came to no good. The energy conservation rules simply
took over. Shutting down everything during off hours became the way a
lot of outfits did things. Don't turn off all your bench gear and you
get a nasty note. I am not aware of full power being dropped during off
hours. That tends to take out things you really do not want to shut down
(fire sensors .). 


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

[ewkehren via time-nuts]

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

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

David N1HAC


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

[Dave B via time-nuts]

Didn’t someone say a while back, that there appeared to be "other data"
present on the transmission, but didn't know what it was, or used
for...   Or did I imagine it.?

Maybe that's why they keep it going?

73.

Dave G0WBX.


On 11/05/17 05:15, time-nuts-requ...@febo.com wrote:
> Message: 5
> Date: Wed, 10 May 2017 21:22:27 +0100
> From: "Alan Melia" 
> To: "Discussion of precise time and frequency measurement"
>   
> Subject: Re: [time-nuts] Anthorn eLoran
> Message-ID: <74167B6989E2494EA086A2F1382A50E1@gnat>
> Content-Type: text/plain; format=flowed; charset="utf-8";
>   reply-type=original
>
> Hi Peter
> Ah that sounds more like it. Aerial maintenaance shuts down the whole site 
> these dats including MSF.  There is really no reason for them to keep it 
> running but I think Trinity House are paying the bill. It cannot be used for 
> nav without Lessay and the output from Sylt, So I muse that they are keeping 
> it powered up because the equipment is quite old now (1990s vintage, the 
> unused kit destined for Loop Head in Ireland) and if the leave it off for 
> any length of time it just wont start again :-))  We all know that syndrome 
> !
>
> I dont know if this is correct but I got the feeling it was not running 
> anything like full power??
>
> Alan
> G3NYK

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Re: [time-nuts] Counter Internal Oscillator Importance with ExternalReference?

[Mattia Rizzi]

Hi,

>Like most counters, the 53230A has an ext-ref input. But it is horrible.
And the ref output is even worse.

I had similar issues using the internal ref. output of the Agilent 53230A
(with OCXO option installed) connected to the Ext. ref input of the 33220A.
The frequency synthtized by the 33220A had pretty bad ADEV values (measured
by the 53220A).
I solved it by connecting the chassis of both instruments using the rear
earth cable screw of the two instrumens. The ADEV measured was limited by
the counter resolution (see [1] and [2])
If I have time I'll try to do the opposite, use the free-running 33220A as
reference for the ext ref. input of the 53220A. Indeed, some noise inside
53220a may be cancel out due to the setup, but I don't have another counter
with a good reference right now :(

cheers,
Mattia

[1] http://i68.tinypic.com/2ynrmaa.png
[2] http://i67.tinypic.com/hrf15i.png

(Message resent due to antispam, sorry for any duplicated message)

2017-05-09 17:03 GMT+02:00 Tom Van Baak :

> Hi Thomas,
>
> About the 53230A -- like many of us I figured there was no point in buying
> the expensive OCXO versions since I have plenty of good 10 MHz references
> around here. So years ago Keysight loaned me two of them for a month: one
> with, and one without OCXO. Like most counters, the 53230A has an ext-ref
> input. But it is horrible. And the ref output is even worse. I think we've
> discussed this on the list before, including ADEV and PN plots. I decided
> not to buy one, ever, until they fixed the problem.
>
> So it could be a nice counter. Someone at Agilent / Keysight needs to
> re-design the int/ext/mux/pll clock handling of the 53230A; someone who
> understands phase noise and short-term stability; someone who honors the
> intent of ext-ref-in and ref-out; someone who keeps stupid microprocessor /
> LCD / comms / power supply noise out of the clock path. Meanwhile I keep my
> old 53132A's and older SR620's and stay away from the 53230A.
>
> If you have your own measurements, please share. Maybe I just got a bad
> sample, I don't know. But the ext-ref performance smelled like poor
> engineering to me. My hope is that someone on the list will hack a 53230A,
> fix the problem, and share the solution with us, or even with Keysight.
>
> /tvb
>
>
> > Hi All;
> >
> > How important is the standard, medium, or high stability reference in
> counters like the 53230A, or FCA3120 when locked to an ultra low phase
> noise external reference? Particularly when making measurements and
> adjustments on other ultra high performance references?
> >
> > I know Agilent sold 53132A counters with an option (H01 I believe) that
> bypassed the internal reference completely when and external reference is
> applied, but I think standard configuration on most counter is to
> discipline the internal reference.
> >
> > Thanks for your thoughts.
> >
> > Thomas Knox
>
>
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Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse

[David G. McGaw]

I too have had a fuse open up due to a failed thermistor in a HP10811.

David N1HAC


On 5/10/17 7:43 PM, Dan Rae wrote:
As I reported the last time this subject came up, or maybe the time 
before, the only time I had an open thermal fuse was in a 10811 that 
had an open thermistor.  I was able to replace that and get the OCXO 
working, but if the fuse had been replaced with a wire link I'm sure 
the entire oven would have been toast.


There have been two types of fuse fitted, all I those have are the 
type that can be fitted with the plug in axial panasonic type, less 
than a dollar from Digikey.  The older ovens had a different type but 
I imagine it's similarly easy to replace.


All my 10811s have the higher temperature Panasonic fuse fitted and I 
sleep well at night...


Dan
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[time-nuts] E1938 info regarding LEDs, push button switch and EFC voltage notation

[James Robbins]

1.  I have just acquired an E1938 and powered it up.  It seems to work.   I
see that it has 4 blinking board LEDs (green, red, yellow, yellow) and a
pushbutton switch at the end of the board opposite to the DB25 connector.
Can anyone point me to either the schematic for the board or what these LEDs
and pushbutton show or do?  

 

2.  Also, there is an "EFC" voltage ("3.69v") marked in magic marker on top
of the can.  Can anyone point me to where I can learn what, if anything,
this voltage notation should be used for?

 

Many thanks.

 

Jim Robbins

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Re: [time-nuts] HP10811 Oscillator Thermal Fuse

[Bob kb8tq]

Hi

Ok, well since I was *asked* to say more :) 

Long ago heavy users of this sort of gear figured out that you wanted to keep 
the OCXO’s on
all the time. That was the way  to make the gear the most stable. That is the 
way you
can use your counter / generator / whatever  when you get to work in the 
morning. A house
standard is not always the way labs are wired. 

Over the years this power on approach ran up against facilities groups that had 
objectives to reduce
building costs. As the costs went down, their bonus went up. A multitude of 
reasons thus
were generated as to why it was a “really good idea” to turn everything off at 
night / at lunch/ 
in odd numbered hours. Most of them were pretty easy to fight. The “fire 
hazard” one was
a bit harder to address. It became a conversation point in buying gear. 

Conversation points tend to flow into odd specification details. They may or 
may not show
up in the written specifications. They are there none the less. The fuse in the 
10811 is there
because of fire / smoke hazard concerns. Is it provable that there a direct 
link from the 
customer “concerns” to the fuse? Without full access to every memo and 
conversation
within HP, it can’t be proven. Based on what people have said over the years, 
it is the case. 

Ultimately it all came to no good. The energy conservation rules simply took 
over. Shutting
down everything during off hours became the way a lot of outfits did things. 
Don’t turn off all
your bench gear and you get a nasty note. I am not aware of full power being 
dropped during 
off hours. That tends to take out things you really do not want to shut down 
(fire sensors …). 

I tend to pick on the US government in the context of gear shutdown. They 
certainly had all 
these issues. The guys from the various labs certainly fought all these 
battles. The government is
far from the only organization that went through all of this between the late 
1960’s and today. 
I’m also not claiming that energy conservation is a bad idea. It comes to mind 
every month
when I get the electric bill ….

Bob


> On May 11, 2017, at 1:58 AM, Hal Murray  wrote:
> 
> 
> kb...@n1k.org said:
>> The is related to safety (full time  power on). As it worked out, the fuse
>> did not help them in that respect. The Fed’s still ruled the gear had to be
>> shut off at night. 
> 
> Could you please say more...
> 
> Does that mean unplugging gear with always-on OCXOs?  Or dumping the main 
> power to the lab when the lights are turned off?
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] Anyone using UBLOX LEA-M8F for GPSDO?

[ewkehren via time-nuts]

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


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

No particular reason for choosing the LEA-M8F other than it looks interesting 
to play with. Actually, who needs a better reason!
Neil
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