Discussion:
time-nuts Digest, Vol 150, Issue 36
(too old to reply)
John Ponsonby
2017-01-17 14:53:47 UTC
Permalink
Re: Low Cost Temperature sensor
The ZNI1000 sensor is based on nickel. As such it must be ferromagnetic. It would thus be absolutely unacceptable in an H-maser where every single small item inside the magnetic shields must be tested for residual ferromagnetism. If ferromagnetism is detectable the item is unacceptable. This applies to every small screw, thermistor, varactor etc. Unfortunately manufacturers of thermistors etc don't state what the wires are made of and it may vary between batches of the same nominal item. This is one of the problems with making H-masers. Though nominally made of copper and zinc, common brass often shows residual ferro magnetism because it is "recovered" metal and is contaminated with iron. That brass must never be used in a magnetic instrument have been known for a very long time. I don't know off-hand if Caesium or Rubidium standards are as sensitive in this regard as H-masers. I guess I could find out from Vanier and Audoin.
John P
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than "Re: Contents of time-nuts digest..."
1. Re: Looking for GPS module (Exactime ET6000/Datum 9390-6000)
2. Re: wifi with time sync (David)
3. Re: wifi with time sync (David)
4. Looking for GPS module (Exactime ET6000/Datum 9390-6000
(Mark Sims)
6. Re: HP 5061A/B Cesium tube conundrum (paul swed)
7. Fluke/Pendulum Counters - Rubidium Timebase (Ed Palmer)
8. Re: Fluke/Pendulum Counters - Rubidium Timebase (Magnus Danielson)
9. Looking for GPS module (Exactime ET6000/Datum 9390-6000)
(Mark Sims)
10. How to create a super Rb standard (Perry Sandeen)
11. Low CostTemperature sensor (Perry Sandeen)
12. Who has a hm H Maser? (Perry Sandeen)
13. Who has a hm H Maser? (Perry Sandeen)
14. TICC update? (Scott Newell)
15. Re: Low CostTemperature sensor (Bill Hawkins)
16. Re: Looking for GPS module (Exactime ET6000/Datum 9390-6000)
17. Re: Low CostTemperature sensor (Jason Ball)
18. Re: Low CostTemperature sensor (Tom Miller)
19. Re: Low CostTemperature sensor (Charles Steinmetz)
20. Re: How to create a super Rb standard (Bob Camp)
21. Re: Low CostTemperature sensor (Scott Stobbe)
22. Re: TICC update? (John Ackermann N8UR)
----------------------------------------------------------------------
Message: 1
Date: Mon, 16 Jan 2017 13:17:32 -0500
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000)
Content-Type: text/plain; charset=utf-8
I did see that one, but I am hoping I can procure something that isn't
from an overseas surplus scrapper. If I can't find anything else, then I
guess it's my only choice. Unfortunately, the Heol folks don't have
anything to offer here either. It's not a WNRO problem, as the week and
date are correct. Even if not, that doesn't affect the GPSDO, only the
timecode generation.
Thanks for replying and the eBay pointer.
If your friends don’t have a CM3 spare, there is one on eBay item 141712522709. It might be worth pulling the GPS part and testing it stand alone as there have been numerous week number roll over problems surfacing. If that is the case for yours then a replacement gets you nowhere.
I’ve had an intermittent problem with my ET6000/9390-6000 GPSDO where the reported error (the FRQ: display on the LCD) initially is OK (low E-12’s) and then creeps up to the limit (~500), and the tracking and locked LEDs go out. I’ve spent some time troubleshooting this and it seems confirmed that the GPS module has finally gone south. I’m asking if anyone has a similar module tucked away somewhere.
The module is basically a Trimble SveeSix-CM3 and is based on the 25040 board. It’s labeled 26889-81 so is a variant of the standard TSIP part. Can anyone help with a replacement? Exact replacement would be ideal of course, but even a standard CM3 would be useful - I’ve done other ‘conversions’ before.
Thanks
Paul
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Message: 2
Date: Mon, 16 Jan 2017 14:12:58 -0600
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] wifi with time sync
Content-Type: text/plain; charset=ISO-8859-1
Modern systems are very aggressive about DVFS (dynamic voltage and
frequency scaling) so it would not surprise me at all. I have run
across this problem on the timescale of one second even on 10 year old
desktop hardware.
Hi
I’d be surprised if a laptop running on wall power and doing a variety of low level
traffic every second is throttling the chip set. It *is* doing something weird and
that certainly is one candidate. I’m not quite as concerned with the *why* the bumps
occur (though I am curious). I’m more interested in the fact that they are really
enormous (compared to other delays). How they do microsecond timing with them
in the mix is the big question.
Bob
------------------------------
Message: 3
Date: Mon, 16 Jan 2017 14:22:15 -0600
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] wifi with time sync
Content-Type: text/plain; charset=ISO-8859-1
Sonos and I guess their competitors do this by dropping WiFi
compatibility. They exist on their own network in the same ISM band
so I wonder how well they coexist with WiFi. Online reports say
poorly under crowded band conditions.
Hi
The push behind this is whole house audio. These guys want to be able to set up WiFi
speakers / mic's all through a home and get proper audio imaging in each room. They likely
also want to use it to figure out which mic you are talking to using time of arrival. They very
much want to do this in real environments (300 WiFi nets in the building). Since they want to
roll it out that way, it’s got to be cheap and fairly robust. They need their gizmo to work with
the infrastructure you already have.
Bob
------------------------------
Message: 4
Date: Mon, 16 Jan 2017 20:39:33 +0000
Subject: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000
Content-Type: text/plain; charset="iso-8859-1"
I recently added code to Lady Heather to support up to 10 external com links (serial or TCPI/IP). One is the receiver port, one will be a TICC, and two are "echo" ports. One echo port echoes all the raw data sent by the receiver and the other does the same thing except the data is formatted as standard NMEA sentences.
One could add the ability to echo out the messages that an SV6 sends and then any GPS receiver that works with Heather could emulate an SV6. You might have to add code to send the proper messages out only when the Datum requests them. That depends upon how the Datum firmware works.
------------------------------
Message: 5
Date: Mon, 16 Jan 2017 12:58:09 -0800
Subject: [time-nuts] HP 5061A/B Cesium tube conundrum
Content-Type: text/plain; charset=us-ascii
I've been doing some work on testing some HP 5061A/B tubes
and came across something that's not making any sense!
The R11 and R12 values marked on the tubes for use with the
new style A11 are supposed to reflect a parallel value
that is 10X larger than the thermistor reading.
This to agree with the ratio of the bridge resistors in the
A11 module.
For instance a 3112A prefix tube shows values of 3.83K
and 42.2K. This gives a parallel value of 3.511K which when
divided by 10 gives 351.1 Ohm. The value marked on the tube
was 352 Ohm. That all makes sense!
Now I have three 3232A prefix tubes and they all do not
reflect this ratio.
For instance one has values of 51.1K and 5.11K which gives
4.65K. This divided by ten gives 465 Ohms. However the
Thermistor value marked on the tube is 915 Ohms!
I tested all three tubes and they come up to the proper
temperature with the thermistor value marked on the tube.
Did HP make a change to the A11 bridge resistor ratio, and
if so where did they document it!
If not and you used the R11 and R12 values you would
seriously overheat the tube!
Cheers,
Corby
------------------------------
Message: 6
Date: Mon, 16 Jan 2017 17:07:19 -0500
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 5061A/B Cesium tube conundrum
Content-Type: text/plain; charset=UTF-8
Corby thats a heck of a puzzle. I am trying to think about how you could
prove it. I have some thoughts that are not at all well formed. It comes
from my experiments on Frankenstein temp control.
If you could please tell me what you might expect the alternate bridge
resistors to be overall I will look through my various bits to see if there
is anything.
Regards
Paul
WB8TSL
I've been doing some work on testing some HP 5061A/B tubes
and came across something that's not making any sense!
The R11 and R12 values marked on the tubes for use with the
new style A11 are supposed to reflect a parallel value
that is 10X larger than the thermistor reading.
This to agree with the ratio of the bridge resistors in the
A11 module.
For instance a 3112A prefix tube shows values of 3.83K
and 42.2K. This gives a parallel value of 3.511K which when
divided by 10 gives 351.1 Ohm. The value marked on the tube
was 352 Ohm. That all makes sense!
Now I have three 3232A prefix tubes and they all do not
reflect this ratio.
For instance one has values of 51.1K and 5.11K which gives
4.65K. This divided by ten gives 465 Ohms. However the
Thermistor value marked on the tube is 915 Ohms!
I tested all three tubes and they come up to the proper
temperature with the thermistor value marked on the tube.
Did HP make a change to the A11 bridge resistor ratio, and
if so where did they document it!
If not and you used the R11 and R12 values you would
seriously overheat the tube!
Cheers,
Corby
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------------------------------
Message: 7
Date: Mon, 16 Jan 2017 16:01:02 -0600
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Fluke/Pendulum Counters - Rubidium Timebase
Content-Type: text/plain; charset=utf-8; format=flowed
I have a Fluke PM6681 counter that just has the basic oscillator. I was
thinking of upgrading it to the Rubidium timebase. From the service
manual, it appears to use an LPRO, but there's nothing obvious regarding
heat sinking. Does anyone have pictures of this installation or, at
least, seen it? Is there any heat sinking at all?
I realize the firmware won't report it as a PM6681R and there will be a
few non-standard work-arounds required, as well as an auxiliary power
supply (the original needs this as well), but I don't see any
showstoppers here. Does anyone have any warnings or advice?
Thanks,
Ed
------------------------------
Message: 8
Date: Mon, 16 Jan 2017 23:42:31 +0100
Subject: Re: [time-nuts] Fluke/Pendulum Counters - Rubidium Timebase
Content-Type: text/plain; charset=utf-8; format=flowed
Ed,
I have a Fluke PM6681 counter that just has the basic oscillator. I was
thinking of upgrading it to the Rubidium timebase. From the service
manual, it appears to use an LPRO, but there's nothing obvious regarding
heat sinking. Does anyone have pictures of this installation or, at
least, seen it? Is there any heat sinking at all?
I realize the firmware won't report it as a PM6681R and there will be a
few non-standard work-arounds required, as well as an auxiliary power
supply (the original needs this as well), but I don't see any
showstoppers here. Does anyone have any warnings or advice?
Asked the former Fluke/Pendulum service engineer Stefan Ledberg, and
The built in Rubidium can use basically any source and have on earlier
models used a Datum or Efratom LPRO-101 model (no heatsink), and later
models used Spectratime LPFRS-01 special Heatsink and adapter from DSUB
to LPRO-equivalent. PSU is added internally that is sharing PCB with the
output amplifier for the additional 10Mhz output on the rear panel. The
PSU and output is no longer in production and I doubt there are any left
at the factory... I can make an inqury if really important, Internally
10Mhz is connected to a 2 pin header and Source is selected with a
jumper. however as stated firmware will still claim std or ocxo
timebase. However my recommendation is to power a Rubidium timebase
externally with off the shelf PSU and just feed the PM6681 on "Ext Ref
in" this will accept most levels of Signal and no fuss needed.
Cheers,
Magnus
------------------------------
Message: 9
Date: Tue, 17 Jan 2017 00:42:42 +0000
Subject: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000)
Content-Type: text/plain; charset="Windows-1252"
On the chip with the "MX" marking on it, what f/w version does it show (usually v5.02 or v5.10)? I have a couple of CM3's configured for TAIP output, but I have the programs for switching them to TSIP or NMEA.
-----------------------
The module is basically a Trimble SveeSix-CM3 and is based on the 25040 board. It’s labeled 26889-81 so is a variant of the standard TSIP part. Can anyone help with a replacement? Exact replacement would be ideal of course, but even a standard CM3 would be useful - I’ve done other ‘conversions’ before.
------------------------------
Message: 10
Date: Tue, 17 Jan 2017 03:24:32 +0000 (UTC)
Subject: [time-nuts] How to create a super Rb standard
Content-Type: text/plain; charset=UTF-8
List
It looks like their is as infinitely small chance of being able to get 5065.
So what can be done with the telco Rb's (mine are analog tuned) to wring the best possible performance from them? Sooper Duper power supplies, Peltier (sp) cooling modules?
Regards,
Perrier
------------------------------
Message: 11
Date: Tue, 17 Jan 2017 03:33:14 +0000 (UTC)
Subject: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=UTF-8
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
------------------------------
Message: 12
Date: Tue, 17 Jan 2017 03:16:06 +0000 (UTC)
Subject: [time-nuts] Who has a hm H Maser?
Content-Type: text/plain; charset=UTF-8
List,
The discussion about building a H Maser has been fascinating however it appears that there will be a long time period before the project reaches fruition.
Where and when did you get it and what was the cost?
Exactly what do you have to do to keep it operating?
Lastly where would one look to get a GOOD used H Maser and what would it cost (rough guess is fine)?
Regards,
Perrier
------------------------------
Message: 13
Date: Tue, 17 Jan 2017 03:16:06 +0000 (UTC)
Subject: [time-nuts] Who has a hm H Maser?
Content-Type: text/plain; charset=UTF-8
List,
The discussion about building a H Maser has been fascinating however it appears that there will be a long time period before the project reaches fruition.
Where and when did you get it and what was the cost?
Exactly what do you have to do to keep it operating?
Lastly where would one look to get a GOOD used H Maser and what would it cost (rough guess is fine)?
Regards,
Perrier
------------------------------
Message: 14
Date: Mon, 16 Jan 2017 22:07:57 -0600
Subject: [time-nuts] TICC update?
Content-Type: text/plain; charset="us-ascii"; format=flowed
I see that my credit card has been charged. Is that a hint that the
TICC project is moving along? Should I start gathering up cables and
SMA adapters?
--
newell N5TNL
------------------------------
Message: 15
Date: Mon, 16 Jan 2017 23:16:29 -0600
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset="us-ascii"
Perrier,
Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate as
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.
Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.
I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.
Bill Hawkins
-----Original Message-----
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
Subject: [time-nuts] Low CostTemperature sensor
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature
sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K
ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
_______________________________________________
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
------------------------------
Message: 16
Date: Tue, 17 Jan 2017 00:23:35 -0500
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000)
Content-Type: text/plain; charset=utf-8
Due to the stickers, I don’t see anything with MX on it, but I presume you mean the ROM. It has 28655-01 and V5.00 on it. The other model number is 26889-81, the -x1 kind of implies that it’s TSIP, and from sniffing the GPS traffic in a prior exercise, I can confirm that it is.
On the chip with the "MX" marking on it, what f/w version does it show (usually v5.02 or v5.10)? I have a couple of CM3's configured for TAIP output, but I have the programs for switching them to TSIP or NMEA.
-----------------------
The module is basically a Trimble SveeSix-CM3 and is based on the 25040 board. It’s labeled 26889-81 so is a variant of the standard TSIP part. Can anyone help with a replacement? Exact replacement would be ideal of course, but even a standard CM3 would be useful - I’ve done other ‘conversions’ before.
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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------------------------------
Message: 17
Date: Tue, 17 Jan 2017 17:11:41 +1100
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=UTF-8
Even cheaper... Diiode as a cheap sensor ?
https://www.arrow.com/en/research-and-events/articles/using-a-simple-diode-as-a-ballpark-temperature-sensor
Perrier,
Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate as
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.
Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.
I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.
Bill Hawkins
-----Original Message-----
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
Subject: [time-nuts] Low CostTemperature sensor
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature
sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K
ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
_______________________________________________
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
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--
--
Teach your kids Science, or somebody else will :/
callsign: vk2vjb
------------------------------
Message: 18
Date: Tue, 17 Jan 2017 01:52:15 -0500
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; format=flowed; charset=utf-8;
reply-type=original
That article has a major error. Anyone know what it is?
----- Original Message -----
To: "Discussion of precise time and frequency measurement"
Sent: Tuesday, January 17, 2017 1:11 AM
Subject: Re: [time-nuts] Low CostTemperature sensor
Even cheaper... Diiode as a cheap sensor ?
https://www.arrow.com/en/research-and-events/articles/using-a-simple-diode-as-a-ballpark-temperature-sensor
Perrier,
Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate as
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.
Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.
I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.
Bill Hawkins
-----Original Message-----
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
Subject: [time-nuts] Low CostTemperature sensor
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature
sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K
ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
_______________________________________________
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
--
--
Teach your kids Science, or somebody else will :/
callsign: vk2vjb
_______________________________________________
To unsubscribe, go to
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------------------------------
Message: 19
Date: Tue, 17 Jan 2017 04:17:25 -0500
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=utf-8; format=flowed
That article has a major error. Anyone know what it is?
Well, the author says the reverse current of a diode is "directly"
proportional to temperature. This could suggest that he means the
relationship is linear (the relationship is actually exponential with
absolute temperature). But that's not really an *error* -- just sloppy.
"Direct" does not necessarily imply "linear." An exponential
relationship is "direct" in the sense that it is what mathematicians
call "injective" (every temperature corresponds to exactly one value of
reverse current).
Then, in discussing the LM95235, he says that it can use the
"collector-emitter junction diode" of a transistor as the sense element.
Of course, a bipolar transistor has no collector-emitter junction.
His diagram correctly shows a diode-connected NPN operating in the
active region (forward biased, not reverse biased as the rest of his
article discusses) as the sensor for the LM95235.
Are any of these what you had in mind, or is there more?
Charles
------------------------------
Message: 20
Date: Tue, 17 Jan 2017 08:20:23 -0500
Subject: Re: [time-nuts] How to create a super Rb standard
Content-Type: text/plain; charset=utf-8
Hi
Since the physics package in the small Rb’s is different than the stuff in the large units,
you have some basic limits on what you can do to improve them. The main things people
have done are to modify them to turn off the temperature compensation and replace it
with some sort of precision controlled thermal enclosure. Pressure compensation is a good
idea on any of these parts (large or small). How much your particular unit benefits is a
“that depends” sort of thing.
Bob
List
It looks like their is as infinitely small chance of being able to get 5065.
So what can be done with the telco Rb's (mine are analog tuned) to wring the best possible performance from them? Sooper Duper power supplies, Peltier (sp) cooling modules?
Regards,
Perrier
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
------------------------------
Message: 21
Date: Tue, 17 Jan 2017 14:10:12 +0000
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=UTF-8
Thermometry based on Diode leakage current wouldn't be impossible I
suppose, you might loose some hair in the process.
The signal levels on the opamp are goofed too.
That article has a major error. Anyone know what it is?
Well, the author says the reverse current of a diode is "directly"
proportional to temperature. This could suggest that he means the
relationship is linear (the relationship is actually exponential with
absolute temperature). But that's not really an *error* -- just sloppy.
"Direct" does not necessarily imply "linear." An exponential
relationship is "direct" in the sense that it is what mathematicians
call "injective" (every temperature corresponds to exactly one value of
reverse current).
Then, in discussing the LM95235, he says that it can use the
"collector-emitter junction diode" of a transistor as the sense element.
Of course, a bipolar transistor has no collector-emitter junction.
His diagram correctly shows a diode-connected NPN operating in the
active region (forward biased, not reverse biased as the rest of his
article discusses) as the sensor for the LM95235.
Are any of these what you had in mind, or is there more?
Charles
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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------------------------------
Message: 22
Date: Tue, 17 Jan 2017 08:14:46 -0600
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] TICC update?
Content-Type: text/plain; charset=UTF-8
⁣Hi Scott --
We received the first-unit sample a couple of weeks ago and it successfully passed all tests, so we gave the go-ahead to do the production build.
We've also sent the Contract Manufacturer the final software versions to be loaded to the Arduino as well as a set of test oscillators for unit testing. (The production code is in master at https://github.com/TAPR/TICC)
My project for this coming weekend is to get the user documentation ready; it's also at GitHub.
I don't know precisely where the CM is in the process right now, but we're still looking for delivery to TAPR by early February.
You can still order: http://tapr.org/kits_ticc.html
John
----
I see that my credit card has been charged. Is that a hint that the
TICC project is moving along? Should I start gathering up cables and
SMA adapters?
--
newell N5TNL
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End of time-nuts Digest, Vol 150, Issue 36
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Bob Camp
2017-01-17 15:17:19 UTC
Permalink
Hi

At least at the “it stops working” level, Rb’s are not as sensitive to residual magnetic fields as what you
describe on H-masers. The scrap guys routinely mangle the shielding around small Rb’s and the parts
still work when we receive them.

On another level, the answer is (of course) yes. Any residual field will have an effect on a magnetically tuned
frequency source. That would definitely drive the material selection for anything in or near the physics package.

Bob
Post by John Ponsonby
Re: Low Cost Temperature sensor
The ZNI1000 sensor is based on nickel. As such it must be ferromagnetic. It would thus be absolutely unacceptable in an H-maser where every single small item inside the magnetic shields must be tested for residual ferromagnetism. If ferromagnetism is detectable the item is unacceptable. This applies to every small screw, thermistor, varactor etc. Unfortunately manufacturers of thermistors etc don't state what the wires are made of and it may vary between batches of the same nominal item. This is one of the problems with making H-masers. Though nominally made of copper and zinc, common brass often shows residual ferro magnetism because it is "recovered" metal and is contaminated with iron. That brass must never be used in a magnetic instrument have been known for a very long time. I don't know off-hand if Caesium or Rubidium standards are as sensitive in this regard as H-masers. I guess I could find out from Vanier and Audoin.
John P
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1. Re: Looking for GPS module (Exactime ET6000/Datum 9390-6000)
2. Re: wifi with time sync (David)
3. Re: wifi with time sync (David)
4. Looking for GPS module (Exactime ET6000/Datum 9390-6000
(Mark Sims)
6. Re: HP 5061A/B Cesium tube conundrum (paul swed)
7. Fluke/Pendulum Counters - Rubidium Timebase (Ed Palmer)
8. Re: Fluke/Pendulum Counters - Rubidium Timebase (Magnus Danielson)
9. Looking for GPS module (Exactime ET6000/Datum 9390-6000)
(Mark Sims)
10. How to create a super Rb standard (Perry Sandeen)
11. Low CostTemperature sensor (Perry Sandeen)
12. Who has a hm H Maser? (Perry Sandeen)
13. Who has a hm H Maser? (Perry Sandeen)
14. TICC update? (Scott Newell)
15. Re: Low CostTemperature sensor (Bill Hawkins)
16. Re: Looking for GPS module (Exactime ET6000/Datum 9390-6000)
17. Re: Low CostTemperature sensor (Jason Ball)
18. Re: Low CostTemperature sensor (Tom Miller)
19. Re: Low CostTemperature sensor (Charles Steinmetz)
20. Re: How to create a super Rb standard (Bob Camp)
21. Re: Low CostTemperature sensor (Scott Stobbe)
22. Re: TICC update? (John Ackermann N8UR)
----------------------------------------------------------------------
Message: 1
Date: Mon, 16 Jan 2017 13:17:32 -0500
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000)
Content-Type: text/plain; charset=utf-8
I did see that one, but I am hoping I can procure something that isn't
from an overseas surplus scrapper. If I can't find anything else, then I
guess it's my only choice. Unfortunately, the Heol folks don't have
anything to offer here either. It's not a WNRO problem, as the week and
date are correct. Even if not, that doesn't affect the GPSDO, only the
timecode generation.
Thanks for replying and the eBay pointer.
If your friends don’t have a CM3 spare, there is one on eBay item 141712522709. It might be worth pulling the GPS part and testing it stand alone as there have been numerous week number roll over problems surfacing. If that is the case for yours then a replacement gets you nowhere.
I’ve had an intermittent problem with my ET6000/9390-6000 GPSDO where the reported error (the FRQ: display on the LCD) initially is OK (low E-12’s) and then creeps up to the limit (~500), and the tracking and locked LEDs go out. I’ve spent some time troubleshooting this and it seems confirmed that the GPS module has finally gone south. I’m asking if anyone has a similar module tucked away somewhere.
The module is basically a Trimble SveeSix-CM3 and is based on the 25040 board. It’s labeled 26889-81 so is a variant of the standard TSIP part. Can anyone help with a replacement? Exact replacement would be ideal of course, but even a standard CM3 would be useful - I’ve done other ‘conversions’ before.
Thanks
Paul
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Message: 2
Date: Mon, 16 Jan 2017 14:12:58 -0600
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] wifi with time sync
Content-Type: text/plain; charset=ISO-8859-1
Modern systems are very aggressive about DVFS (dynamic voltage and
frequency scaling) so it would not surprise me at all. I have run
across this problem on the timescale of one second even on 10 year old
desktop hardware.
Hi
I’d be surprised if a laptop running on wall power and doing a variety of low level
traffic every second is throttling the chip set. It *is* doing something weird and
that certainly is one candidate. I’m not quite as concerned with the *why* the bumps
occur (though I am curious). I’m more interested in the fact that they are really
enormous (compared to other delays). How they do microsecond timing with them
in the mix is the big question.
Bob
------------------------------
Message: 3
Date: Mon, 16 Jan 2017 14:22:15 -0600
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] wifi with time sync
Content-Type: text/plain; charset=ISO-8859-1
Sonos and I guess their competitors do this by dropping WiFi
compatibility. They exist on their own network in the same ISM band
so I wonder how well they coexist with WiFi. Online reports say
poorly under crowded band conditions.
Hi
The push behind this is whole house audio. These guys want to be able to set up WiFi
speakers / mic's all through a home and get proper audio imaging in each room. They likely
also want to use it to figure out which mic you are talking to using time of arrival. They very
much want to do this in real environments (300 WiFi nets in the building). Since they want to
roll it out that way, it’s got to be cheap and fairly robust. They need their gizmo to work with
the infrastructure you already have.
Bob
------------------------------
Message: 4
Date: Mon, 16 Jan 2017 20:39:33 +0000
Subject: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000
Content-Type: text/plain; charset="iso-8859-1"
I recently added code to Lady Heather to support up to 10 external com links (serial or TCPI/IP). One is the receiver port, one will be a TICC, and two are "echo" ports. One echo port echoes all the raw data sent by the receiver and the other does the same thing except the data is formatted as standard NMEA sentences.
One could add the ability to echo out the messages that an SV6 sends and then any GPS receiver that works with Heather could emulate an SV6. You might have to add code to send the proper messages out only when the Datum requests them. That depends upon how the Datum firmware works.
------------------------------
Message: 5
Date: Mon, 16 Jan 2017 12:58:09 -0800
Subject: [time-nuts] HP 5061A/B Cesium tube conundrum
Content-Type: text/plain; charset=us-ascii
I've been doing some work on testing some HP 5061A/B tubes
and came across something that's not making any sense!
The R11 and R12 values marked on the tubes for use with the
new style A11 are supposed to reflect a parallel value
that is 10X larger than the thermistor reading.
This to agree with the ratio of the bridge resistors in the
A11 module.
For instance a 3112A prefix tube shows values of 3.83K
and 42.2K. This gives a parallel value of 3.511K which when
divided by 10 gives 351.1 Ohm. The value marked on the tube
was 352 Ohm. That all makes sense!
Now I have three 3232A prefix tubes and they all do not
reflect this ratio.
For instance one has values of 51.1K and 5.11K which gives
4.65K. This divided by ten gives 465 Ohms. However the
Thermistor value marked on the tube is 915 Ohms!
I tested all three tubes and they come up to the proper
temperature with the thermistor value marked on the tube.
Did HP make a change to the A11 bridge resistor ratio, and
if so where did they document it!
If not and you used the R11 and R12 values you would
seriously overheat the tube!
Cheers,
Corby
------------------------------
Message: 6
Date: Mon, 16 Jan 2017 17:07:19 -0500
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 5061A/B Cesium tube conundrum
Content-Type: text/plain; charset=UTF-8
Corby thats a heck of a puzzle. I am trying to think about how you could
prove it. I have some thoughts that are not at all well formed. It comes
from my experiments on Frankenstein temp control.
If you could please tell me what you might expect the alternate bridge
resistors to be overall I will look through my various bits to see if there
is anything.
Regards
Paul
WB8TSL
I've been doing some work on testing some HP 5061A/B tubes
and came across something that's not making any sense!
The R11 and R12 values marked on the tubes for use with the
new style A11 are supposed to reflect a parallel value
that is 10X larger than the thermistor reading.
This to agree with the ratio of the bridge resistors in the
A11 module.
For instance a 3112A prefix tube shows values of 3.83K
and 42.2K. This gives a parallel value of 3.511K which when
divided by 10 gives 351.1 Ohm. The value marked on the tube
was 352 Ohm. That all makes sense!
Now I have three 3232A prefix tubes and they all do not
reflect this ratio.
For instance one has values of 51.1K and 5.11K which gives
4.65K. This divided by ten gives 465 Ohms. However the
Thermistor value marked on the tube is 915 Ohms!
I tested all three tubes and they come up to the proper
temperature with the thermistor value marked on the tube.
Did HP make a change to the A11 bridge resistor ratio, and
if so where did they document it!
If not and you used the R11 and R12 values you would
seriously overheat the tube!
Cheers,
Corby
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------------------------------
Message: 7
Date: Mon, 16 Jan 2017 16:01:02 -0600
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Fluke/Pendulum Counters - Rubidium Timebase
Content-Type: text/plain; charset=utf-8; format=flowed
I have a Fluke PM6681 counter that just has the basic oscillator. I was
thinking of upgrading it to the Rubidium timebase. From the service
manual, it appears to use an LPRO, but there's nothing obvious regarding
heat sinking. Does anyone have pictures of this installation or, at
least, seen it? Is there any heat sinking at all?
I realize the firmware won't report it as a PM6681R and there will be a
few non-standard work-arounds required, as well as an auxiliary power
supply (the original needs this as well), but I don't see any
showstoppers here. Does anyone have any warnings or advice?
Thanks,
Ed
------------------------------
Message: 8
Date: Mon, 16 Jan 2017 23:42:31 +0100
Subject: Re: [time-nuts] Fluke/Pendulum Counters - Rubidium Timebase
Content-Type: text/plain; charset=utf-8; format=flowed
Ed,
I have a Fluke PM6681 counter that just has the basic oscillator. I was
thinking of upgrading it to the Rubidium timebase. From the service
manual, it appears to use an LPRO, but there's nothing obvious regarding
heat sinking. Does anyone have pictures of this installation or, at
least, seen it? Is there any heat sinking at all?
I realize the firmware won't report it as a PM6681R and there will be a
few non-standard work-arounds required, as well as an auxiliary power
supply (the original needs this as well), but I don't see any
showstoppers here. Does anyone have any warnings or advice?
Asked the former Fluke/Pendulum service engineer Stefan Ledberg, and
The built in Rubidium can use basically any source and have on earlier
models used a Datum or Efratom LPRO-101 model (no heatsink), and later
models used Spectratime LPFRS-01 special Heatsink and adapter from DSUB
to LPRO-equivalent. PSU is added internally that is sharing PCB with the
output amplifier for the additional 10Mhz output on the rear panel. The
PSU and output is no longer in production and I doubt there are any left
at the factory... I can make an inqury if really important, Internally
10Mhz is connected to a 2 pin header and Source is selected with a
jumper. however as stated firmware will still claim std or ocxo
timebase. However my recommendation is to power a Rubidium timebase
externally with off the shelf PSU and just feed the PM6681 on "Ext Ref
in" this will accept most levels of Signal and no fuss needed.
Cheers,
Magnus
------------------------------
Message: 9
Date: Tue, 17 Jan 2017 00:42:42 +0000
Subject: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000)
Content-Type: text/plain; charset="Windows-1252"
On the chip with the "MX" marking on it, what f/w version does it show (usually v5.02 or v5.10)? I have a couple of CM3's configured for TAIP output, but I have the programs for switching them to TSIP or NMEA.
-----------------------
The module is basically a Trimble SveeSix-CM3 and is based on the 25040 board. It’s labeled 26889-81 so is a variant of the standard TSIP part. Can anyone help with a replacement? Exact replacement would be ideal of course, but even a standard CM3 would be useful - I’ve done other ‘conversions’ before.
------------------------------
Message: 10
Date: Tue, 17 Jan 2017 03:24:32 +0000 (UTC)
Subject: [time-nuts] How to create a super Rb standard
Content-Type: text/plain; charset=UTF-8
List
It looks like their is as infinitely small chance of being able to get 5065.
So what can be done with the telco Rb's (mine are analog tuned) to wring the best possible performance from them? Sooper Duper power supplies, Peltier (sp) cooling modules?
Regards,
Perrier
------------------------------
Message: 11
Date: Tue, 17 Jan 2017 03:33:14 +0000 (UTC)
Subject: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=UTF-8
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
------------------------------
Message: 12
Date: Tue, 17 Jan 2017 03:16:06 +0000 (UTC)
Subject: [time-nuts] Who has a hm H Maser?
Content-Type: text/plain; charset=UTF-8
List,
The discussion about building a H Maser has been fascinating however it appears that there will be a long time period before the project reaches fruition.
Where and when did you get it and what was the cost?
Exactly what do you have to do to keep it operating?
Lastly where would one look to get a GOOD used H Maser and what would it cost (rough guess is fine)?
Regards,
Perrier
------------------------------
Message: 13
Date: Tue, 17 Jan 2017 03:16:06 +0000 (UTC)
Subject: [time-nuts] Who has a hm H Maser?
Content-Type: text/plain; charset=UTF-8
List,
The discussion about building a H Maser has been fascinating however it appears that there will be a long time period before the project reaches fruition.
Where and when did you get it and what was the cost?
Exactly what do you have to do to keep it operating?
Lastly where would one look to get a GOOD used H Maser and what would it cost (rough guess is fine)?
Regards,
Perrier
------------------------------
Message: 14
Date: Mon, 16 Jan 2017 22:07:57 -0600
Subject: [time-nuts] TICC update?
Content-Type: text/plain; charset="us-ascii"; format=flowed
I see that my credit card has been charged. Is that a hint that the
TICC project is moving along? Should I start gathering up cables and
SMA adapters?
--
newell N5TNL
------------------------------
Message: 15
Date: Mon, 16 Jan 2017 23:16:29 -0600
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset="us-ascii"
Perrier,
Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate as
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.
Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.
I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.
Bill Hawkins
-----Original Message-----
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
Subject: [time-nuts] Low CostTemperature sensor
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
_______________________________________________
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
------------------------------
Message: 16
Date: Tue, 17 Jan 2017 00:23:35 -0500
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000)
Content-Type: text/plain; charset=utf-8
Due to the stickers, I don’t see anything with MX on it, but I presume you mean the ROM. It has 28655-01 and V5.00 on it. The other model number is 26889-81, the -x1 kind of implies that it’s TSIP, and from sniffing the GPS traffic in a prior exercise, I can confirm that it is.
On the chip with the "MX" marking on it, what f/w version does it show (usually v5.02 or v5.10)? I have a couple of CM3's configured for TAIP output, but I have the programs for switching them to TSIP or NMEA.
-----------------------
The module is basically a Trimble SveeSix-CM3 and is based on the 25040 board. It’s labeled 26889-81 so is a variant of the standard TSIP part. Can anyone help with a replacement? Exact replacement would be ideal of course, but even a standard CM3 would be useful - I’ve done other ‘conversions’ before.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
------------------------------
Message: 17
Date: Tue, 17 Jan 2017 17:11:41 +1100
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=UTF-8
Even cheaper... Diiode as a cheap sensor ?
https://www.arrow.com/en/research-and-events/articles/using-a-simple-diode-as-a-ballpark-temperature-sensor
Perrier,
Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate as
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.
Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.
I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.
Bill Hawkins
-----Original Message-----
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
Subject: [time-nuts] Low CostTemperature sensor
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
_______________________________________________
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and follow the instructions there.
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--
--
Teach your kids Science, or somebody else will :/
callsign: vk2vjb
------------------------------
Message: 18
Date: Tue, 17 Jan 2017 01:52:15 -0500
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; format=flowed; charset=utf-8;
reply-type=original
That article has a major error. Anyone know what it is?
----- Original Message -----
To: "Discussion of precise time and frequency measurement"
Sent: Tuesday, January 17, 2017 1:11 AM
Subject: Re: [time-nuts] Low CostTemperature sensor
Even cheaper... Diiode as a cheap sensor ?
https://www.arrow.com/en/research-and-events/articles/using-a-simple-diode-as-a-ballpark-temperature-sensor
Perrier,
Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate as
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.
Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.
I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.
Bill Hawkins
-----Original Message-----
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
Subject: [time-nuts] Low CostTemperature sensor
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
_______________________________________________
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
--
--
Teach your kids Science, or somebody else will :/
callsign: vk2vjb
_______________________________________________
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and follow the instructions there.
------------------------------
Message: 19
Date: Tue, 17 Jan 2017 04:17:25 -0500
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=utf-8; format=flowed
That article has a major error. Anyone know what it is?
Well, the author says the reverse current of a diode is "directly"
proportional to temperature. This could suggest that he means the
relationship is linear (the relationship is actually exponential with
absolute temperature). But that's not really an *error* -- just sloppy.
"Direct" does not necessarily imply "linear." An exponential
relationship is "direct" in the sense that it is what mathematicians
call "injective" (every temperature corresponds to exactly one value of
reverse current).
Then, in discussing the LM95235, he says that it can use the
"collector-emitter junction diode" of a transistor as the sense element.
Of course, a bipolar transistor has no collector-emitter junction.
His diagram correctly shows a diode-connected NPN operating in the
active region (forward biased, not reverse biased as the rest of his
article discusses) as the sensor for the LM95235.
Are any of these what you had in mind, or is there more?
Charles
------------------------------
Message: 20
Date: Tue, 17 Jan 2017 08:20:23 -0500
Subject: Re: [time-nuts] How to create a super Rb standard
Content-Type: text/plain; charset=utf-8
Hi
Since the physics package in the small Rb’s is different than the stuff in the large units,
you have some basic limits on what you can do to improve them. The main things people
have done are to modify them to turn off the temperature compensation and replace it
with some sort of precision controlled thermal enclosure. Pressure compensation is a good
idea on any of these parts (large or small). How much your particular unit benefits is a
“that depends” sort of thing.
Bob
List
It looks like their is as infinitely small chance of being able to get 5065.
So what can be done with the telco Rb's (mine are analog tuned) to wring the best possible performance from them? Sooper Duper power supplies, Peltier (sp) cooling modules?
Regards,
Perrier
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
------------------------------
Message: 21
Date: Tue, 17 Jan 2017 14:10:12 +0000
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=UTF-8
Thermometry based on Diode leakage current wouldn't be impossible I
suppose, you might loose some hair in the process.
The signal levels on the opamp are goofed too.
That article has a major error. Anyone know what it is?
Well, the author says the reverse current of a diode is "directly"
proportional to temperature. This could suggest that he means the
relationship is linear (the relationship is actually exponential with
absolute temperature). But that's not really an *error* -- just sloppy.
"Direct" does not necessarily imply "linear." An exponential
relationship is "direct" in the sense that it is what mathematicians
call "injective" (every temperature corresponds to exactly one value of
reverse current).
Then, in discussing the LM95235, he says that it can use the
"collector-emitter junction diode" of a transistor as the sense element.
Of course, a bipolar transistor has no collector-emitter junction.
His diagram correctly shows a diode-connected NPN operating in the
active region (forward biased, not reverse biased as the rest of his
article discusses) as the sensor for the LM95235.
Are any of these what you had in mind, or is there more?
Charles
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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------------------------------
Message: 22
Date: Tue, 17 Jan 2017 08:14:46 -0600
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] TICC update?
Content-Type: text/plain; charset=UTF-8
⁣Hi Scott --
We received the first-unit sample a couple of weeks ago and it successfully passed all tests, so we gave the go-ahead to do the production build.
We've also sent the Contract Manufacturer the final software versions to be loaded to the Arduino as well as a set of test oscillators for unit testing. (The production code is in master at https://github.com/TAPR/TICC)
My project for this coming weekend is to get the user documentation ready; it's also at GitHub.
I don't know precisely where the CM is in the process right now, but we're still looking for delivery to TAPR by early February.
You can still order: http://tapr.org/kits_ticc.html
John
----
I see that my credit card has been charged. Is that a hint that the
TICC project is moving along? Should I start gathering up cables and
SMA adapters?
--
newell N5TNL
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Subject: Digest Footer
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End of time-nuts Digest, Vol 150, Issue 36
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Scott Stobbe
2017-01-17 16:39:50 UTC
Permalink
As an aside, some materials can change their magnetic properties after cold
working/forming like stainless steel for example.
Post by Bob Camp
Hi
At least at the “it stops working” level, Rb’s are not as sensitive to
residual magnetic fields as what you
describe on H-masers. The scrap guys routinely mangle the shielding around
small Rb’s and the parts
still work when we receive them.
On another level, the answer is (of course) yes. Any residual field will
have an effect on a magnetically tuned
frequency source. That would definitely drive the material selection for
anything in or near the physics package.
Bob
Post by John Ponsonby
Re: Low Cost Temperature sensor
The ZNI1000 sensor is based on nickel. As such it must be ferromagnetic.
It would thus be absolutely unacceptable in an H-maser where every single
small item inside the magnetic shields must be tested for residual
ferromagnetism. If ferromagnetism is detectable the item is unacceptable.
This applies to every small screw, thermistor, varactor etc. Unfortunately
manufacturers of thermistors etc don't state what the wires are made of and
it may vary between batches of the same nominal item. This is one of the
problems with making H-masers. Though nominally made of copper and zinc,
common brass often shows residual ferro magnetism because it is "recovered"
metal and is contaminated with iron. That brass must never be used in a
magnetic instrument have been known for a very long time. I don't know
off-hand if Caesium or Rubidium standards are as sensitive in this regard
as H-masers. I guess I could find out from Vanier and Audoin.
Post by John Ponsonby
John P
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of time-nuts digest..."
1. Re: Looking for GPS module (Exactime ET6000/Datum 9390-6000)
2. Re: wifi with time sync (David)
3. Re: wifi with time sync (David)
4. Looking for GPS module (Exactime ET6000/Datum 9390-6000
(Mark Sims)
6. Re: HP 5061A/B Cesium tube conundrum (paul swed)
7. Fluke/Pendulum Counters - Rubidium Timebase (Ed Palmer)
8. Re: Fluke/Pendulum Counters - Rubidium Timebase (Magnus Danielson)
9. Looking for GPS module (Exactime ET6000/Datum 9390-6000)
(Mark Sims)
10. How to create a super Rb standard (Perry Sandeen)
11. Low CostTemperature sensor (Perry Sandeen)
12. Who has a hm H Maser? (Perry Sandeen)
13. Who has a hm H Maser? (Perry Sandeen)
14. TICC update? (Scott Newell)
15. Re: Low CostTemperature sensor (Bill Hawkins)
16. Re: Looking for GPS module (Exactime ET6000/Datum 9390-6000)
17. Re: Low CostTemperature sensor (Jason Ball)
18. Re: Low CostTemperature sensor (Tom Miller)
19. Re: Low CostTemperature sensor (Charles Steinmetz)
20. Re: How to create a super Rb standard (Bob Camp)
21. Re: Low CostTemperature sensor (Scott Stobbe)
22. Re: TICC update? (John Ackermann N8UR)
----------------------------------------------------------------------
Message: 1
Date: Mon, 16 Jan 2017 13:17:32 -0500
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000)
Content-Type: text/plain; charset=utf-8
I did see that one, but I am hoping I can procure something that isn't
from an overseas surplus scrapper. If I can't find anything else, then I
guess it's my only choice. Unfortunately, the Heol folks don't have
anything to offer here either. It's not a WNRO problem, as the week and
date are correct. Even if not, that doesn't affect the GPSDO, only the
timecode generation.
Thanks for replying and the eBay pointer.
If your friends don’t have a CM3 spare, there is one on eBay item
141712522709. It might be worth pulling the GPS part and testing it stand
alone as there have been numerous week number roll over problems surfacing.
If that is the case for yours then a replacement gets you nowhere.
Post by John Ponsonby
I’ve had an intermittent problem with my ET6000/9390-6000 GPSDO where
the reported error (the FRQ: display on the LCD) initially is OK (low
E-12’s) and then creeps up to the limit (~500), and the tracking and locked
LEDs go out. I’ve spent some time troubleshooting this and it seems
confirmed that the GPS module has finally gone south. I’m asking if anyone
has a similar module tucked away somewhere.
Post by John Ponsonby
The module is basically a Trimble SveeSix-CM3 and is based on the
25040 board. It’s labeled 26889-81 so is a variant of the standard TSIP
part. Can anyone help with a replacement? Exact replacement would be ideal
of course, but even a standard CM3 would be useful - I’ve done other
‘conversions’ before.
Post by John Ponsonby
Thanks
Paul
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Post by John Ponsonby
and follow the instructions there.
"The power of accurate observation is commonly called cynicism by
those who have not got it. »
Post by John Ponsonby
George Bernard Shaw
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Post by John Ponsonby
and follow the instructions there.
------------------------------
Message: 2
Date: Mon, 16 Jan 2017 14:12:58 -0600
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] wifi with time sync
Content-Type: text/plain; charset=ISO-8859-1
Modern systems are very aggressive about DVFS (dynamic voltage and
frequency scaling) so it would not surprise me at all. I have run
across this problem on the timescale of one second even on 10 year old
desktop hardware.
Hi
I’d be surprised if a laptop running on wall power and doing a variety
of low level
Post by John Ponsonby
traffic every second is throttling the chip set. It *is* doing
something weird and
Post by John Ponsonby
that certainly is one candidate. I’m not quite as concerned with the
*why* the bumps
Post by John Ponsonby
occur (though I am curious). I’m more interested in the fact that they
are really
Post by John Ponsonby
enormous (compared to other delays). How they do microsecond timing
with them
Post by John Ponsonby
in the mix is the big question.
Bob
------------------------------
Message: 3
Date: Mon, 16 Jan 2017 14:22:15 -0600
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] wifi with time sync
Content-Type: text/plain; charset=ISO-8859-1
Sonos and I guess their competitors do this by dropping WiFi
compatibility. They exist on their own network in the same ISM band
so I wonder how well they coexist with WiFi. Online reports say
poorly under crowded band conditions.
Hi
The push behind this is whole house audio. These guys want to be able
to set up WiFi
Post by John Ponsonby
speakers / mic's all through a home and get proper audio imaging in
each room. They likely
Post by John Ponsonby
also want to use it to figure out which mic you are talking to using
time of arrival. They very
Post by John Ponsonby
much want to do this in real environments (300 WiFi nets in the
building). Since they want to
Post by John Ponsonby
roll it out that way, it’s got to be cheap and fairly robust. They
need their gizmo to work with
Post by John Ponsonby
the infrastructure you already have.
Bob
------------------------------
Message: 4
Date: Mon, 16 Jan 2017 20:39:33 +0000
Subject: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000
namprd17.prod.outlook.com>
Post by John Ponsonby
Content-Type: text/plain; charset="iso-8859-1"
I recently added code to Lady Heather to support up to 10 external com
links (serial or TCPI/IP). One is the receiver port, one will be a TICC,
and two are "echo" ports. One echo port echoes all the raw data sent by
the receiver and the other does the same thing except the data is formatted
as standard NMEA sentences.
Post by John Ponsonby
One could add the ability to echo out the messages that an SV6 sends
and then any GPS receiver that works with Heather could emulate an SV6.
You might have to add code to send the proper messages out only when the
Datum requests them. That depends upon how the Datum firmware works.
Post by John Ponsonby
------------------------------
Message: 5
Date: Mon, 16 Jan 2017 12:58:09 -0800
Subject: [time-nuts] HP 5061A/B Cesium tube conundrum
Content-Type: text/plain; charset=us-ascii
I've been doing some work on testing some HP 5061A/B tubes
and came across something that's not making any sense!
The R11 and R12 values marked on the tubes for use with the
new style A11 are supposed to reflect a parallel value
that is 10X larger than the thermistor reading.
This to agree with the ratio of the bridge resistors in the
A11 module.
For instance a 3112A prefix tube shows values of 3.83K
and 42.2K. This gives a parallel value of 3.511K which when
divided by 10 gives 351.1 Ohm. The value marked on the tube
was 352 Ohm. That all makes sense!
Now I have three 3232A prefix tubes and they all do not
reflect this ratio.
For instance one has values of 51.1K and 5.11K which gives
4.65K. This divided by ten gives 465 Ohms. However the
Thermistor value marked on the tube is 915 Ohms!
I tested all three tubes and they come up to the proper
temperature with the thermistor value marked on the tube.
Did HP make a change to the A11 bridge resistor ratio, and
if so where did they document it!
If not and you used the R11 and R12 values you would
seriously overheat the tube!
Cheers,
Corby
------------------------------
Message: 6
Date: Mon, 16 Jan 2017 17:07:19 -0500
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 5061A/B Cesium tube conundrum
gmail.com>
Post by John Ponsonby
Content-Type: text/plain; charset=UTF-8
Corby thats a heck of a puzzle. I am trying to think about how you could
prove it. I have some thoughts that are not at all well formed. It comes
from my experiments on Frankenstein temp control.
If you could please tell me what you might expect the alternate bridge
resistors to be overall I will look through my various bits to see if
there
Post by John Ponsonby
is anything.
Regards
Paul
WB8TSL
I've been doing some work on testing some HP 5061A/B tubes
and came across something that's not making any sense!
The R11 and R12 values marked on the tubes for use with the
new style A11 are supposed to reflect a parallel value
that is 10X larger than the thermistor reading.
This to agree with the ratio of the bridge resistors in the
A11 module.
For instance a 3112A prefix tube shows values of 3.83K
and 42.2K. This gives a parallel value of 3.511K which when
divided by 10 gives 351.1 Ohm. The value marked on the tube
was 352 Ohm. That all makes sense!
Now I have three 3232A prefix tubes and they all do not
reflect this ratio.
For instance one has values of 51.1K and 5.11K which gives
4.65K. This divided by ten gives 465 Ohms. However the
Thermistor value marked on the tube is 915 Ohms!
I tested all three tubes and they come up to the proper
temperature with the thermistor value marked on the tube.
Did HP make a change to the A11 bridge resistor ratio, and
if so where did they document it!
If not and you used the R11 and R12 values you would
seriously overheat the tube!
Cheers,
Corby
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and follow the instructions there.
------------------------------
Message: 7
Date: Mon, 16 Jan 2017 16:01:02 -0600
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Fluke/Pendulum Counters - Rubidium Timebase
Content-Type: text/plain; charset=utf-8; format=flowed
I have a Fluke PM6681 counter that just has the basic oscillator. I was
thinking of upgrading it to the Rubidium timebase. From the service
manual, it appears to use an LPRO, but there's nothing obvious regarding
heat sinking. Does anyone have pictures of this installation or, at
least, seen it? Is there any heat sinking at all?
I realize the firmware won't report it as a PM6681R and there will be a
few non-standard work-arounds required, as well as an auxiliary power
supply (the original needs this as well), but I don't see any
showstoppers here. Does anyone have any warnings or advice?
Thanks,
Ed
------------------------------
Message: 8
Date: Mon, 16 Jan 2017 23:42:31 +0100
Subject: Re: [time-nuts] Fluke/Pendulum Counters - Rubidium Timebase
Content-Type: text/plain; charset=utf-8; format=flowed
Ed,
I have a Fluke PM6681 counter that just has the basic oscillator. I
was
Post by John Ponsonby
thinking of upgrading it to the Rubidium timebase. From the service
manual, it appears to use an LPRO, but there's nothing obvious
regarding
Post by John Ponsonby
heat sinking. Does anyone have pictures of this installation or, at
least, seen it? Is there any heat sinking at all?
I realize the firmware won't report it as a PM6681R and there will be a
few non-standard work-arounds required, as well as an auxiliary power
supply (the original needs this as well), but I don't see any
showstoppers here. Does anyone have any warnings or advice?
Asked the former Fluke/Pendulum service engineer Stefan Ledberg, and
The built in Rubidium can use basically any source and have on earlier
models used a Datum or Efratom LPRO-101 model (no heatsink), and later
models used Spectratime LPFRS-01 special Heatsink and adapter from DSUB
to LPRO-equivalent. PSU is added internally that is sharing PCB with the
output amplifier for the additional 10Mhz output on the rear panel. The
PSU and output is no longer in production and I doubt there are any left
at the factory... I can make an inqury if really important, Internally
10Mhz is connected to a 2 pin header and Source is selected with a
jumper. however as stated firmware will still claim std or ocxo
timebase. However my recommendation is to power a Rubidium timebase
externally with off the shelf PSU and just feed the PM6681 on "Ext Ref
in" this will accept most levels of Signal and no fuss needed.
Cheers,
Magnus
------------------------------
Message: 9
Date: Tue, 17 Jan 2017 00:42:42 +0000
Subject: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000)
namprd17.prod.outlook.com>
Post by John Ponsonby
Content-Type: text/plain; charset="Windows-1252"
On the chip with the "MX" marking on it, what f/w version does it show
(usually v5.02 or v5.10)? I have a couple of CM3's configured for TAIP
output, but I have the programs for switching them to TSIP or NMEA.
Post by John Ponsonby
-----------------------
The module is basically a Trimble SveeSix-CM3 and is based on the
25040 board. It’s labeled 26889-81 so is a variant of the standard TSIP
part. Can anyone help with a replacement? Exact replacement would be ideal
of course, but even a standard CM3 would be useful - I’ve done other
‘conversions’ before.
Post by John Ponsonby
------------------------------
Message: 10
Date: Tue, 17 Jan 2017 03:24:32 +0000 (UTC)
Subject: [time-nuts] How to create a super Rb standard
Content-Type: text/plain; charset=UTF-8
List
It looks like their is as infinitely small chance of being able to get
5065.
Post by John Ponsonby
So what can be done with the telco Rb's (mine are analog tuned) to
wring the best possible performance from them? Sooper Duper power supplies,
Peltier (sp) cooling modules?
Post by John Ponsonby
Regards,
Perrier
------------------------------
Message: 11
Date: Tue, 17 Jan 2017 03:33:14 +0000 (UTC)
Subject: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=UTF-8
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature
sensor.
Post by John Ponsonby
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K
ohm sensors.
Post by John Ponsonby
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
------------------------------
Message: 12
Date: Tue, 17 Jan 2017 03:16:06 +0000 (UTC)
Subject: [time-nuts] Who has a hm H Maser?
Content-Type: text/plain; charset=UTF-8
List,
The discussion about building a H Maser has been fascinating however it
appears that there will be a long time period before the project reaches
fruition.
Post by John Ponsonby
Where and when did you get it and what was the cost?
Exactly what do you have to do to keep it operating?
Lastly where would one look to get a GOOD used H Maser and what would
it cost (rough guess is fine)?
Post by John Ponsonby
Regards,
Perrier
------------------------------
Message: 13
Date: Tue, 17 Jan 2017 03:16:06 +0000 (UTC)
Subject: [time-nuts] Who has a hm H Maser?
Content-Type: text/plain; charset=UTF-8
List,
The discussion about building a H Maser has been fascinating however it
appears that there will be a long time period before the project reaches
fruition.
Post by John Ponsonby
Where and when did you get it and what was the cost?
Exactly what do you have to do to keep it operating?
Lastly where would one look to get a GOOD used H Maser and what would
it cost (rough guess is fine)?
Post by John Ponsonby
Regards,
Perrier
------------------------------
Message: 14
Date: Mon, 16 Jan 2017 22:07:57 -0600
Subject: [time-nuts] TICC update?
Content-Type: text/plain; charset="us-ascii"; format=flowed
I see that my credit card has been charged. Is that a hint that the
TICC project is moving along? Should I start gathering up cables and
SMA adapters?
--
newell N5TNL
------------------------------
Message: 15
Date: Mon, 16 Jan 2017 23:16:29 -0600
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset="us-ascii"
Perrier,
Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate as
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.
Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.
I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.
Bill Hawkins
-----Original Message-----
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
Subject: [time-nuts] Low CostTemperature sensor
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
_______________________________________________
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
------------------------------
Message: 16
Date: Tue, 17 Jan 2017 00:23:35 -0500
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Looking for GPS module (Exactime ET6000/Datum
9390-6000)
Content-Type: text/plain; charset=utf-8
Due to the stickers, I don’t see anything with MX on it, but I presume
you mean the ROM. It has 28655-01 and V5.00 on it. The other model number
is 26889-81, the -x1 kind of implies that it’s TSIP, and from sniffing the
GPS traffic in a prior exercise, I can confirm that it is.
Post by John Ponsonby
On the chip with the "MX" marking on it, what f/w version does it
show (usually v5.02 or v5.10)? I have a couple of CM3's configured for
TAIP output, but I have the programs for switching them to TSIP or NMEA.
Post by John Ponsonby
-----------------------
The module is basically a Trimble SveeSix-CM3 and is based on the
25040 board. It’s labeled 26889-81 so is a variant of the standard TSIP
part. Can anyone help with a replacement? Exact replacement would be ideal
of course, but even a standard CM3 would be useful - I’ve done other
‘conversions’ before.
Post by John Ponsonby
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
Post by John Ponsonby
and follow the instructions there.
------------------------------
Message: 17
Date: Tue, 17 Jan 2017 17:11:41 +1100
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low CostTemperature sensor
gmail.com>
Post by John Ponsonby
Content-Type: text/plain; charset=UTF-8
Even cheaper... Diiode as a cheap sensor ?
https://www.arrow.com/en/research-and-events/articles/
using-a-simple-diode-as-a-ballpark-temperature-sensor
Post by John Ponsonby
Perrier,
Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate
as
Post by John Ponsonby
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.
Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.
I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.
Bill Hawkins
-----Original Message-----
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
Subject: [time-nuts] Low CostTemperature sensor
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt 1K
ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
_______________________________________________
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
--
--
Teach your kids Science, or somebody else will :/
callsign: vk2vjb
------------------------------
Message: 18
Date: Tue, 17 Jan 2017 01:52:15 -0500
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; format=flowed; charset=utf-8;
reply-type=original
That article has a major error. Anyone know what it is?
----- Original Message -----
To: "Discussion of precise time and frequency measurement"
Sent: Tuesday, January 17, 2017 1:11 AM
Subject: Re: [time-nuts] Low CostTemperature sensor
Even cheaper... Diiode as a cheap sensor ?
https://www.arrow.com/en/research-and-events/articles/
using-a-simple-diode-as-a-ballpark-temperature-sensor
Post by John Ponsonby
Perrier,
Google finds a Siemens NI1000 sensor that follows the nickel curve.
Nickel is popular in industrial control for cost, but not as accurate
as
Post by John Ponsonby
platinum. Converting the platinum curve to accurate temperatures
requires a second order equation, but has been done with 0.1% analog
converters.
Digi-key has ZNI devices as surface mount parts. Sparse data said
nothing about a platinum curve.
I'm curious because my former employer did very well selling platinum
RTD sensors, usually 100 ohms at the triple point.
Bill Hawkins
-----Original Message-----
Perry
Post by John Ponsonby
Sandeen via time-nuts
Sent: Monday, January 16, 2017 9:33 PM
Subject: [time-nuts] Low CostTemperature sensor
List,
A while back there was much discussion about temperature sensors.
One simple inexpensive one to consider would be the ZNI1000Temperature sensor.
It's 1K ohms at 0C and it replicates the temperature curve of the Pt
1K
Post by John Ponsonby
ohm sensors.
It's about $3 from Digi-Key.
FWIW YMMY
Regards,
Perrier
_______________________________________________
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
--
--
Teach your kids Science, or somebody else will :/
callsign: vk2vjb
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
------------------------------
Message: 19
Date: Tue, 17 Jan 2017 04:17:25 -0500
Subject: Re: [time-nuts] Low CostTemperature sensor
Content-Type: text/plain; charset=utf-8; format=flowed
That article has a major error. Anyone know what it is?
Well, the author says the reverse current of a diode is "directly"
proportional to temperature. This could suggest that he means the
relationship is linear (the relationship is actually exponential with
absolute temperature). But that's not really an *error* -- just sloppy.
"Direct" does not necessarily imply "linear." An exponential
relationship is "direct" in the sense that it is what mathematicians
call "injective" (every temperature corresponds to exactly one value of
reverse current).
Then, in discussing the LM95235, he says that it can use the
"collector-emitter junction diode" of a transistor as the sense element.
Of course, a bipolar transistor has no collector-emitter junction.
His diagram correctly shows a diode-connected NPN operating in the
active region (forward biased, not reverse biased as the rest of his
article discusses) as the sensor for the LM95235.
Are any of these what you had in mind, or is there more?
Charles
------------------------------
Message: 20
Date: Tue, 17 Jan 2017 08:20:23 -0500
Subject: Re: [time-nuts] How to create a super Rb standard
Content-Type: text/plain; charset=utf-8
Hi
Since the physics package in the small Rb’s is different than the stuff
in the large units,
Post by John Ponsonby
you have some basic limits on what you can do to improve them. The main
things people
Post by John Ponsonby
have done are to modify them to turn off the temperature compensation
and replace it
Post by John Ponsonby
with some sort of precision controlled thermal enclosure. Pressure
compensation is a good
Post by John Ponsonby
idea on any of these parts (large or small). How much your particular
unit benefits is a
Post by John Ponsonby
“that depends” sort of thing.
Bob
On Jan 16, 2017, at 10:24 PM, Perry Sandeen via time-nuts <
List
It looks like their is as infinitely small chance of being able to get
5065.
Post by John Ponsonby
So what can be done with the telco Rb's (mine are analog tuned) to
wring the best possible performance from them? Sooper Duper power supplies,
Peltier (sp) cooling modules?
Post by John Ponsonby
Regards,
Perrier
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
Post by John Ponsonby
and follow the instructions there.
------------------------------
Message: 21
Date: Tue, 17 Jan 2017 14:10:12 +0000
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low CostTemperature sensor
<CALg-KtMYS4eNfa0Zf_41M50zxi75+GLbD+SkZUbNBa9+
Content-Type: text/plain; charset=UTF-8
Thermometry based on Diode leakage current wouldn't be impossible I
suppose, you might loose some hair in the process.
The signal levels on the opamp are goofed too.
On Tue, Jan 17, 2017 at 4:19 AM Charles Steinmetz <
That article has a major error. Anyone know what it is?
Well, the author says the reverse current of a diode is "directly"
proportional to temperature. This could suggest that he means the
relationship is linear (the relationship is actually exponential with
absolute temperature). But that's not really an *error* -- just
sloppy.
Post by John Ponsonby
"Direct" does not necessarily imply "linear." An exponential
relationship is "direct" in the sense that it is what mathematicians
call "injective" (every temperature corresponds to exactly one value of
reverse current).
Then, in discussing the LM95235, he says that it can use the
"collector-emitter junction diode" of a transistor as the sense
element.
Post by John Ponsonby
Of course, a bipolar transistor has no collector-emitter junction.
His diagram correctly shows a diode-connected NPN operating in the
active region (forward biased, not reverse biased as the rest of his
article discusses) as the sensor for the LM95235.
Are any of these what you had in mind, or is there more?
Charles
_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
------------------------------
Message: 22
Date: Tue, 17 Jan 2017 08:14:46 -0600
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] TICC update?
Content-Type: text/plain; charset=UTF-8
⁣Hi Scott --
We received the first-unit sample a couple of weeks ago and it
successfully passed all tests, so we gave the go-ahead to do the production
build.
Post by John Ponsonby
We've also sent the Contract Manufacturer the final software versions
to be loaded to the Arduino as well as a set of test oscillators for unit
testing. (The production code is in master at
https://github.com/TAPR/TICC)
Post by John Ponsonby
My project for this coming weekend is to get the user documentation
ready; it's also at GitHub.
Post by John Ponsonby
I don't know precisely where the CM is in the process right now, but
we're still looking for delivery to TAPR by early February.
Post by John Ponsonby
You can still order: http://tapr.org/kits_ticc.html
John
----
On Jan 16, 2017, 10:17 PM, at 10:17 PM, Scott Newell <
I see that my credit card has been charged. Is that a hint that the
TICC project is moving along? Should I start gathering up cables and
SMA adapters?
--
newell N5TNL
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Post by John Ponsonby
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Ed Palmer
2017-01-17 16:13:26 UTC
Permalink
Magnus,
Thanks for the info and please pass my thanks on to Stefan.

Yes, I usually do use an external timebase for the PM6681. I need to do
some troubleshooting on the unit and thought I'd do a timebase upgrade
while I was in there. I want to make some measurements that are
independent of my house standard (an Efratom FRK).

I haven't quite decided whether the upgrade will be an OCXO or a Rb. I
have both LPRO and X72 Rb units sitting on the shelf so the cost will be
minimal. If I go with a Rb, I'll just find a small power supply that
will fit rather than looking for the distribution board. There appears
to be enough info in the service manual that figuring out the
connections shouldn't be a problem.

Ed
Ed,
I have a Fluke PM6681 counter that just has the basic oscillator. I was
thinking of upgrading it to the Rubidium timebase. From the service
manual, it appears to use an LPRO, but there's nothing obvious regarding
heat sinking. Does anyone have pictures of this installation or, at
least, seen it? Is there any heat sinking at all?
I realize the firmware won't report it as a PM6681R and there will be a
few non-standard work-arounds required, as well as an auxiliary power
supply (the original needs this as well), but I don't see any
showstoppers here. Does anyone have any warnings or advice?
Asked the former Fluke/Pendulum service engineer Stefan Ledberg, and
The built in Rubidium can use basically any source and have on earlier
models used a Datum or Efratom LPRO-101 model (no heatsink), and later
models used Spectratime LPFRS-01 special Heatsink and adapter from DSUB
to LPRO-equivalent. PSU is added internally that is sharing PCB with the
output amplifier for the additional 10Mhz output on the rear panel. The
PSU and output is no longer in production and I doubt there are any left
at the factory... I can make an inqury if really important, Internally
10Mhz is connected to a 2 pin header and Source is selected with a
jumper. however as stated firmware will still claim std or ocxo
timebase. However my recommendation is to power a Rubidium timebase
externally with off the shelf PSU and just feed the PM6681 on "Ext Ref
in" this will accept most levels of Signal and no fuss needed.
Cheers,
Magnus
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Magnus Danielson
2017-01-18 00:45:24 UTC
Permalink
Ed,

I will make sure to forward your thanks to Stefan.

A small OCXO could be supported by the built-in PSU, so that might be
more practical. Really depends on what you want to do.

One of these days I will work on the calibration stuff on the
CNT-81/PM6681 I have.

Cheers,
Magnus
Post by Ed Palmer
Magnus,
Thanks for the info and please pass my thanks on to Stefan.
Yes, I usually do use an external timebase for the PM6681. I need to do
some troubleshooting on the unit and thought I'd do a timebase upgrade
while I was in there. I want to make some measurements that are
independent of my house standard (an Efratom FRK).
I haven't quite decided whether the upgrade will be an OCXO or a Rb. I
have both LPRO and X72 Rb units sitting on the shelf so the cost will be
minimal. If I go with a Rb, I'll just find a small power supply that
will fit rather than looking for the distribution board. There appears
to be enough info in the service manual that figuring out the
connections shouldn't be a problem.
Ed
Ed,
I have a Fluke PM6681 counter that just has the basic oscillator. I
was
thinking of upgrading it to the Rubidium timebase. From the service
manual, it appears to use an LPRO, but there's nothing obvious
regarding
heat sinking. Does anyone have pictures of this installation or, at
least, seen it? Is there any heat sinking at all?
I realize the firmware won't report it as a PM6681R and there will be a
few non-standard work-arounds required, as well as an auxiliary power
supply (the original needs this as well), but I don't see any
showstoppers here. Does anyone have any warnings or advice?
Asked the former Fluke/Pendulum service engineer Stefan Ledberg, and
The built in Rubidium can use basically any source and have on earlier
models used a Datum or Efratom LPRO-101 model (no heatsink), and later
models used Spectratime LPFRS-01 special Heatsink and adapter from DSUB
to LPRO-equivalent. PSU is added internally that is sharing PCB with the
output amplifier for the additional 10Mhz output on the rear panel. The
PSU and output is no longer in production and I doubt there are any left
at the factory... I can make an inqury if really important, Internally
10Mhz is connected to a 2 pin header and Source is selected with a
jumper. however as stated firmware will still claim std or ocxo
timebase. However my recommendation is to power a Rubidium timebase
externally with off the shelf PSU and just feed the PM6681 on "Ext Ref
in" this will accept most levels of Signal and no fuss needed.
Cheers,
Magnus
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Hal Murray
2017-01-17 17:40:02 UTC
Permalink
Post by John Ponsonby
Though nominally made of copper and zinc, common brass often shows residual
ferro magnetism because it is "recovered" metal and is contaminated with
iron. That brass must never be used in a magnetic instrument have been known
for a very long time.
What do people use?
--
These are my opinions. I hate spam.



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Alex Pummer
2017-01-17 18:13:21 UTC
Permalink
Titanium, it is expensive but strong and non magnetic at all

73

KJ6UHN

Alex
Post by Hal Murray
Post by John Ponsonby
Though nominally made of copper and zinc, common brass often shows residual
ferro magnetism because it is "recovered" metal and is contaminated with
iron. That brass must never be used in a magnetic instrument have been known
for a very long time.
What do people use?
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