Re: [time-nuts] disappearance of NIST UT1 time service

somewhat related: if someone has NTP service distributing TAI, that could be useful for monitoring how the leap second is added to UTC-distributing normal NTP servers come December 31st? might have to set one up myself if there are none in Europe? AW On Thu, Oct 27, 2016 at 1:50 PM, Mike Cook

Re: [time-nuts] Difference in manufacturing for fundamental tone, 3rd, and 5th overtone crystals

On 10/27/2016 4:50 PM, Bob Camp wrote: Hi Crystals are highly optimized for the specific overtone they are intended to operate on. In fact, you can fiddle them to the point that they no longer have a “fundamental” response. Bob That's interesting. Every overtone crystal I have played

Re: [time-nuts] Temp/Humidity control systems

There is a wax which melts at 70F. Phase change stores and releases a lot of heat. Somewhat optimistic IMHO https://www.wired.com/2015/05/table-sucks-heat-lower-ac-bills/ http://www.stacoolvest.com/news/ Technical: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4809117/

Re: [time-nuts] Temp/Humidity control systems?

I am in Florida and my garage gets quite warm and damp. I installed a window A/C unit and the results were mixed. It got cooler, but not necessarily dryer. And my utility bill suffered. So I built up a simple controller to control the 120VAC power to the A/C. It is a thermoplastic plastic

Re: [time-nuts] Temp/Humidity control systems?

Have you looked into wine cellar equipment? They sell equipment that's designed to control temperature and humidity for custom built wine cellars that can be anything from an retrofitted insulated closet to a small room. I think that they also sell prefab cellars to put into an existing

Re: [time-nuts] Difference in manufacturing for fundamental tone, 3rd, and 5th overtone crystals

Hi Indeed, there are processes for things like filter crystals that reduce the (very) near by responses. There are approaches for things like SC’s to take out the somewhat further out “bothersome” stuff. Bob > On Oct 27, 2016, at 7:53 PM, Magnus Danielson > wrote:

Re: [time-nuts] Temp/Humidity control systems?

Years ago I had to deal with this and the instruments and sensors we used matched well against dry and wet bulb measurements. I suspect consumer level stuff varies considerably in reliability and accuracy. The capacitive sensors are tricky to use because they require AC excitation to prevent

[time-nuts] Temperature/Humidity

Simple, build your room (8 x 12), use a water sealing paint paint, install a split mini cooling unit at approx.8,000 BTU, set temperature below oven temperature of the equipment.Carefully choose AC size (not to big). Door at far end of room. ___

Re: [time-nuts] Temp/Humidity control systems?

Dew Point measurement technology is limited by surface energy problems, in the near vicinity of the surface,Van der Waals or London forces create uncertainties in the physical processes and dew point instruments always seem to have these uncertainties. The physical equilibrium on the surface of

Re: [time-nuts] Temp/Humidity control systems?

In message <20161027134312.ga18...@panix.com>, Ron Bean writes: >And since this is time-nuts: Measuring humidity accurately is tricky. >According to people who have tested them, commercial electronic humidity >sensors, when tested in a lab, have never come anywhere close to the

Re: [time-nuts] Difference in manufacturing for fundamental tone, 3rd, and 5th overtone crystals

Hi, Hmm, such fiddeling could maybe also apply to nearby alternative modes of the crystals, even if I guess it would be harder to do meaningful dents on them. Cheers, Magnus On 10/28/2016 01:50 AM, Bob Camp wrote: Hi Crystals are highly optimized for the specific overtone they are

Re: [time-nuts] Difference in manufacturing for fundamental tone, 3rd, and 5th overtone crystals

Hi Crystals are highly optimized for the specific overtone they are intended to operate on. In fact, you can fiddle them to the point that they no longer have a “fundamental” response. Bob > On Oct 27, 2016, at 6:42 PM, Attila Kinali wrote: > > Moin, > > I have stumbled

Re: [time-nuts] Temp/Humidity control systems?

Ha! That is the system my brother Greg Scace designed and built while at NIST. He has given a lot of papers around the world on its metrology technology. On the side, he manufactures the reference calibration tools for espresso machines

Re: [time-nuts] Temp/Humidity control systems?

You are correct to question commercial humidity sensors. It seems to have come about because no-one can make a dollar by selling humidity. Manufacturers do not tell the truth, they think ours is as good as theirs so we should claim the same accuracy. People buy these sensors, believe them, and

[time-nuts] Difference in manufacturing for fundamental tone, 3rd, and 5th overtone crystals

Moin, I have stumbled over another question I am unable to answer using the tools I have available: Is there any fundamental difference in manufacturing fundamental and overtone chrystals. Or to be more precise: is there an optimization process during manufacturing that makes a crystal more

Re: [time-nuts] Aging and Thermal Correction in Holdover

From: Attila Kinali To: Discussion of precise time and frequency measurement Sent: Thursday, October 27, 2016 1:45 PM Subject: Re: [time-nuts] Aging and Thermal Correction in Holdover On Thu, 27 Oct 2016 16:13:06 + (UTC) Bob Stewart

Re: [time-nuts] Temp/Humidity control systems?

Just for the fun of it, here is how NIST measures humidity. https://www.nist.gov/sites/default/files/documents/calibrations/sp250-83.pdf On Thu, Oct 27, 2016 at 3:30 PM, William H. Fite wrote: > NIST-traceable hygrometers are readily available in the $200-$400 range. > > Or

Re: [time-nuts] Temp/Humidity control systems?

NIST-traceable hygrometers are readily available in the $200-$400 range. Or you can get a couple of airtight boxes of precisely the same volume and go gravimetric... On Thu, Oct 27, 2016 at 9:43 AM, Ron Bean wrote: > >* You cannot "feel" absolute

Re: [time-nuts] Temp/Humidity control systems?

>* You cannot "feel" absolute humidity, always measure it. And since this is time-nuts: Measuring humidity accurately is tricky. According to people who have tested them, commercial electronic humidity sensors, when tested in a lab, have never come anywhere close to the accuracy claimed in the

Re: [time-nuts] Aging and Thermal Correction in Holdover

On Thu, 27 Oct 2016 16:13:06 + (UTC) Bob Stewart wrote: > Thanks for confirming that the thermal impact on the aging rate is minimal. > I had suspected that that was so, but had no easy way to tell. It is _probably_ minimal. How large it is depends on your setup. But from

Re: [time-nuts] Temp/Humidity control systems?

On 10/27/16 8:06 AM, Poul-Henning Kamp wrote: In message <837330db-2015-4ae5-8c9c-f444f569f...@n1k.org>, Bob Camp writes: Your “time cave” does not have a specific spec on temperature or on humidity. You get to pick a number for either one. Anything in the “non condensing” (let’s call

Re: [time-nuts] Temp/Humidity control systems?

On 10/27/16 8:02 AM, John Hawkinson wrote: jimlux wrote on Thu, 27 Oct 2016 at 07:51:37 -0700 in : (and frankly, if someone made something that opened/closed my windows, I'd love that too, for the same reason.

Re: [time-nuts] Temp/Humidity control systems

I'm not sure I follow the insulation is bad argument, thermal time constant = RC, better insulation, longer time constant. On Thu, Oct 27, 2016 at 12:37 PM, Mike Naruta AA8K wrote: > On 10/27/2016 03:41 AM, Poul-Henning Kamp wrote: > >> Over insulating is a 100% sure-fire way

Re: [time-nuts] Temp/Humidity control systems

On 10/27/2016 03:41 AM, Poul-Henning Kamp wrote: Over insulating is a 100% sure-fire way to get unstable temperature inside, because it amplifies the consequences of any change in power dissipation. It is a classic mistake to build a 100mm insulated enclosure inside an office-like environment

Re: [time-nuts] Aging and Thermal Correction in Holdover

Hi Attila, Thanks for confirming that the thermal impact on the aging rate is minimal.  I had suspected that that was so, but had no easy way to tell.  Since I want to keep this as simple as possible, I'll probably stay with a simple division of the DAC delta over 3.5 days.  And since the

Re: [time-nuts] Temp/Humidity control systems?

Use one of the Wine cellar room coolers -- they keep the temperature and humidity fairly constant. Typically ~55F but can vary it. Breezaire and others are vendors in this area. The units look like a window airconditioner. This will work to keep the temperature in a given range, but with rather

Re: [time-nuts] Temp/Humidity control systems?

Mine were 8' x 10' x 7'. "Local pickup only" ;) The -20F chamber was 4' x 4' x 7'. The -80F chamber was 2' x 2' x 5'. How much space will you need, John? Chances are you could pick up a small one on ebay and avoid all the jackleg schemes. On Thursday, October 27, 2016, Poul-Henning Kamp

Re: [time-nuts] Temp/Humidity control systems?

On 10/27/2016 11:06 AM, Poul-Henning Kamp wrote: This is why a lot of people in costal climates who ventilate their basement during summer "to dry out the basement" get the exact opposite result: The air outside is a lot wetter than on the inside. I learned this myself last summer. We have

Re: [time-nuts] Temp/Humidity control systems?

In message , jimlux writes: >Disadvantages: >1) It leaks >2) It grows stuff (even with additives to prevent it) Antifreeze prevented that for me. >3) you've increased the number of thermal transfers: refrigerator coils >to air to

Re: [time-nuts] Temp/Humidity control systems?

jimlux wrote on Thu, 27 Oct 2016 at 07:51:37 -0700 in : > (and frankly, if someone made something that opened/closed my > windows, I'd love that too, for the same reason.

Re: [time-nuts] Temp/Humidity control systems?

In message <837330db-2015-4ae5-8c9c-f444f569f...@n1k.org>, Bob Camp writes: >Your “time cave” does not have a specific spec on temperature or on humidity. >You get to pick a number for either one. Anything in the “non condensing” >(let’s >call it < 80%) range for humidity is likely ok.

Re: [time-nuts] Temp/Humidity control systems?

On 10/27/16 7:37 AM, Bob Camp wrote: Hi Ok, take this with a bit of caution …. Your “time cave” does not have a specific spec on temperature or on humidity. You get to pick a number for either one. Anything in the “non condensing” (let’s call it < 80%) range for humidity is likely ok.

Re: [time-nuts] Temp/Humidity control systems?

Hi Ok, take this with a bit of caution …. Your “time cave” does not have a specific spec on temperature or on humidity. You get to pick a number for either one. Anything in the “non condensing” (let’s call it < 80%) range for humidity is likely ok. Temperature up to 40C is probably ok for

Re: [time-nuts] Temp/Humidity control systems?

On 10/27/16 6:30 AM, Poul-Henning Kamp wrote: In message , "David J Taylor" writes: You can buy the smallest "window" airconditioner and "plumb" it to your chamber (I used dryer vent hose, cardboard, and lots of duct tape) Attached is a plot

Re: [time-nuts] Temp/Humidity control systems?

In message , "David J Taylor" writes: >You can buy the smallest "window" airconditioner and "plumb" it to your >chamber (I used dryer vent hose, cardboard, and lots of duct tape) > >Attached is a plot temperature and RH of an insulated box about 1.2

Re: [time-nuts] Temp/Humidity control systems?

In message <20161027131226.0d5a72e62b2c91f2e13b6...@kinali.ch>, Attila Kinali w rites: >> Stop! >> >> Over insulating is a 100% sure-fire way to get unstable temperature inside, >> because it amplifies the consequences of any change in power dissipation. >> >> It is a classic mistake

Re: [time-nuts] Temp/Humidity control systems?

On 10/27/16 2:43 AM, Neville Michie wrote: The nature of air is that when you heat it by one degree Celcius the humidity falls by 10%. That does not change the moisture content of the air, just the activity of the same amount of water vapour with regards to any material with an equilibrium

Re: [time-nuts] Temp/Humidity control systems?

On 10/27/16 2:17 AM, David J Taylor wrote: From: jimlux You can buy the smallest "window" airconditioner and "plumb" it to your chamber (I used dryer vent hose, cardboard, and lots of duct tape) Attached is a plot temperature and RH of an insulated box about 1.2 meter wide, 2 meters tall and

Re: [time-nuts] Temp/Humidity control systems?

Hoi Poul-Henning, On Thu, 27 Oct 2016 07:41:48 + "Poul-Henning Kamp" wrote: > >Probably the easiest is to get some glass/mineral wool insulation and > >put it over all the walls, including ceiling and floor. I do not recommend > >any foam or styropor based insulation as

[time-nuts] disappearance of NIST UT1 time service

Hi, Does anyone know what happened to the NIST UT1 time service managed by Dr. Judah Levine? I lost contact with the server ut1-time.colorado.edu on the 24th this month at 20:15 UTC and there has been no response to NTP requests since. I mailed Judah to find out what happened but have not

Re: [time-nuts] FTS-1000A Oscillator - Oven mod

Kapton tape. On Thu, Oct 27, 2016 at 12:15 AM, Ed Palmer wrote: I recently bought an unused FTS-1000A Oscillator. My previous experience and Christopher Hoover's recent experience warned me that with time and heat, the red rubber blanket that surrounds the oven will bond the oven assembly

Re: [time-nuts] Temp/Humidity control systems?

The nature of air is that when you heat it by one degree Celcius the humidity falls by 10%. That does not change the moisture content of the air, just the activity of the same amount of water vapour with regards to any material with an equilibrium moisture content. So it is important to control

Re: [time-nuts] Temp/Humidity control systems?

From: jimlux You can buy the smallest "window" airconditioner and "plumb" it to your chamber (I used dryer vent hose, cardboard, and lots of duct tape) Attached is a plot temperature and RH of an insulated box about 1.2 meter wide, 2 meters tall and 60 cm deep, filled with 100 or so 750 ml

Re: [time-nuts] Temp/Humidity control systems?

In message <20161026210517.26c0fd397b1cae5ba9c12...@kinali.ch>, Attila Kinali w rites: >Probably the easiest is to get some glass/mineral wool insulation and >put it over all the walls, including ceiling and floor. I do not recommend >any foam or styropor based insulation as almost all

Re: [time-nuts] Temp/Humidity control systems?

In message , "William H. Fite" writes: >Rick, professional environmental chambers [...] And they come up on fleabay with surprising regularity. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20

Re: [time-nuts] Temp/Humidity control systems?

In message <5810d2d2.2070...@febo.com>, John Ackermann N8UR writes: >I may have the opportunity to build a small "clock room" and am >considering whether I could make it an environmentally controlled space. > I'd like to learn about the options for doing this. You first need to

Re: [time-nuts] WWV receivers?

In message <5a002554-8d90-4c75-95da-21db45d61...@kfu.com>, Nick Sayer via time- nuts writes: >If you’re in North America, a CHU receiver is a lot easier to make >than WWV/WWVH. The CHU timecode is just BEL 103 AFSK at 300 baud - >it was a one-chip solution 20 years ago when I made one in

Re: [time-nuts] Timing from Iridium satellites

stewart.c...@gmail.com said: > I hope this is not too blatantly commercial for this list Looks good to me. Thanks. Are the specs for extracting timing from Iridium available without NDA or $$$? Page 6 shows several hardware boards/boxes. The NooElec NESDR Mini 2 USB Stick seems like the