Re: [time-nuts] How long do ovens take to cool to ambient, after power is removed?
Hi All, Considering this old stuff was that good, what's the best that's currently available now? How does that compare to the best that's ever been? Dan On 10/3/2014 7:19 AM, time-nuts-requ...@febo.com wrote: Tom, Nice performance. Wish we could get that today! My fairly modern BVA is nowhere near that stability. If you open up a brand new DOCXO you will see a crystal designed in the 70's and an oscillator circuit designed sometime in the 30's or 40's, maybe updated to a more or less modern transistor.. Once you have the recipe, there is no need to change it really.. Bye, Said ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient, after power is removed?
The best now is the 8607 BVA OCXO from Oscilloquartz (now part of ADVA optical networking). On Fri, Oct 3, 2014 at 2:33 PM, Dan Kemppainen d...@irtelemetrics.com wrote: Hi All, Considering this old stuff was that good, what's the best that's currently available now? How does that compare to the best that's ever been? Dan On 10/3/2014 7:19 AM, time-nuts-requ...@febo.com wrote: Tom, Nice performance. Wish we could get that today! My fairly modern BVA is nowhere near that stability. If you open up a brand new DOCXO you will see a crystal designed in the 70's and an oscillator circuit designed sometime in the 30's or 40's, maybe updated to a more or less modern transistor.. Once you have the recipe, there is no need to change it really.. Bye, Said ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?
On 10/02/2014 06:03 AM, Richard (Rick) Karlquist wrote: On 10/1/2014 1:04 PM, Hal Murray wrote: drkir...@kirkbymicrowave.co.uk said: Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. The question is though, how long is thing thing likely to take too cool? I'd expect an exponential decay so you need to specify how close to ambient you want to get. I'd guess a ballpark of 10x the warm up rate. You can probably measure it if you have the warmup graph. Turn it off, wait a while, turn it on, measure the freq, consult warmup graph. When I was still with Agilent, I did some experiments with unpowered 10811's. Both the oven and oscillator were unpowered and I measured the temperature by looking at the B mode resonance of the crystal. I wanted to get rid of any linear frequency drift. As a rough rule of thumb, 1 hour of cool down is pretty good for most purposes. For extreme measurements, I would allow 10 hours. This reduced any exponential tail to below the ability to measure temperature and/or below the effects of the ambient. I had to put a box over it to reduce the effects of air currents. If I did not do that, then 1 hour was all I needed. Just putting a card-board box around the oscillator does indeed make short term deviation (breath, hand-waving, walking around and pushing air) reduce significantly. What is needed to get anything decent out of crap oscillators. Doesn't do as much for longer term shifts (AC, day-variations etc) Your cool-off numbers is about where I would guess for better ovens. Naturally, a fan can speed the process up, but let it sit there for some time without the fan to have less temperature gradients. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?
The most extreme example of slow ovenized oscillator warm-up I've seen is the vintage hp106. These mid-1960's oscillators were designed as the ultimate, hp way, pre-atomic, frequency standard -- expected to be powered up, uninterrupted, for years and decades. So there was no hurry in the (perhaps once-in-a-lifetime) initial warm-up. Here's a plot/photo of one I recently tested: http://leapsecond.com/museum/hp106a/ These HP-106 oscillators are among the best I have ever measured: stability and daily drift rates in the very low -13's. Like the SR-71, these were designed by gut and slide rule. And yet achieved extreme performance, even by today's standards. The amazing thing -- as you know from your enviable career at HP -- is that an instrument produced in 1964 can still work 50 years later in 2014. No blown fuses, no electrolytics, no filaments, no f/w upgrades, no Y2K, no decaying EEPROM, no batteries, not even any IC's. No user s/w, no USB, no drivers, no OS. Not even an on/off switch! Just a 5-pin 24VDC backup or 2-prong AC cord in and a pure 5 MHz BNC out, that's all. How many of the instruments we use today will still work out-of-the-box in 2064? /tvb - Original Message - From: Richard (Rick) Karlquist rich...@karlquist.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Cc: hmur...@megapathdsl.net Sent: Wednesday, October 01, 2014 9:03 PM Subject: Re: [time-nuts] How long do ovens take to cool to ambient after power is removed? On 10/1/2014 1:04 PM, Hal Murray wrote: drkir...@kirkbymicrowave.co.uk said: Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. The question is though, how long is thing thing likely to take too cool? I'd expect an exponential decay so you need to specify how close to ambient you want to get. I'd guess a ballpark of 10x the warm up rate. You can probably measure it if you have the warmup graph. Turn it off, wait a while, turn it on, measure the freq, consult warmup graph. When I was still with Agilent, I did some experiments with unpowered 10811's. Both the oven and oscillator were unpowered and I measured the temperature by looking at the B mode resonance of the crystal. I wanted to get rid of any linear frequency drift. As a rough rule of thumb, 1 hour of cool down is pretty good for most purposes. For extreme measurements, I would allow 10 hours. This reduced any exponential tail to below the ability to measure temperature and/or below the effects of the ambient. I had to put a box over it to reduce the effects of air currents. If I did not do that, then 1 hour was all I needed. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?
Tom, Nice performance. Wish we could get that today! My fairly modern BVA is nowhere near that stability. If you open up a brand new DOCXO you will see a crystal designed in the 70's and an oscillator circuit designed sometime in the 30's or 40's, maybe updated to a more or less modern transistor.. Once you have the recipe, there is no need to change it really.. Bye, Said Sent From iPhone On Oct 2, 2014, at 11:58, Tom Van Baak t...@leapsecond.com wrote: The most extreme example of slow ovenized oscillator warm-up I've seen is the vintage hp106. These mid-1960's oscillators were designed as the ultimate, hp way, pre-atomic, frequency standard -- expected to be powered up, uninterrupted, for years and decades. So there was no hurry in the (perhaps once-in-a-lifetime) initial warm-up. Here's a plot/photo of one I recently tested: http://leapsecond.com/museum/hp106a/ These HP-106 oscillators are among the best I have ever measured: stability and daily drift rates in the very low -13's. Like the SR-71, these were designed by gut and slide rule. And yet achieved extreme performance, even by today's standards. The amazing thing -- as you know from your enviable career at HP -- is that an instrument produced in 1964 can still work 50 years later in 2014. No blown fuses, no electrolytics, no filaments, no f/w upgrades, no Y2K, no decaying EEPROM, no batteries, not even any IC's. No user s/w, no USB, no drivers, no OS. Not even an on/off switch! Just a 5-pin 24VDC backup or 2-prong AC cord in and a pure 5 MHz BNC out, that's all. How many of the instruments we use today will still work out-of-the-box in 2064? /tvb - Original Message - From: Richard (Rick) Karlquist rich...@karlquist.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Cc: hmur...@megapathdsl.net Sent: Wednesday, October 01, 2014 9:03 PM Subject: Re: [time-nuts] How long do ovens take to cool to ambient after power is removed? On 10/1/2014 1:04 PM, Hal Murray wrote: drkir...@kirkbymicrowave.co.uk said: Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. The question is though, how long is thing thing likely to take too cool? I'd expect an exponential decay so you need to specify how close to ambient you want to get. I'd guess a ballpark of 10x the warm up rate. You can probably measure it if you have the warmup graph. Turn it off, wait a while, turn it on, measure the freq, consult warmup graph. When I was still with Agilent, I did some experiments with unpowered 10811's. Both the oven and oscillator were unpowered and I measured the temperature by looking at the B mode resonance of the crystal. I wanted to get rid of any linear frequency drift. As a rough rule of thumb, 1 hour of cool down is pretty good for most purposes. For extreme measurements, I would allow 10 hours. This reduced any exponential tail to below the ability to measure temperature and/or below the effects of the ambient. I had to put a box over it to reduce the effects of air currents. If I did not do that, then 1 hour was all I needed. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?
Len Cutler was pretty much allowed to do whatever he wanted on the HP106 and he produced the proverbial doomsday machine. I think the SR-71 analogy is good here, except that Kelly Johnson had a lot more support from his management. Len always wanted to make an optically pumped cesium as his ultimate doomsday machine, but management never funded it. He proudly had a 106 on display in his office. I wish I had asked him how he got such low aging crystals. 10811 crystals never got much lower than about 1 part in 10^-10 per day. Rick Karlquist N6RK On 10/2/2014 11:58 AM, Tom Van Baak wrote: The most extreme example of slow ovenized oscillator warm-up I've seen is the vintage hp106. These mid-1960's oscillators were designed as the ultimate, hp way, pre-atomic, frequency standard -- expected to be powered up, uninterrupted, for years and decades. So there was no hurry in the (perhaps once-in-a-lifetime) initial warm-up. Here's a plot/photo of one I recently tested: http://leapsecond.com/museum/hp106a/ These HP-106 oscillators are among the best I have ever measured: stability and daily drift rates in the very low -13's. Like the SR-71, these were designed by gut and slide rule. And yet achieved extreme performance, even by today's standards. The amazing thing -- as you know from your enviable career at HP -- is that an instrument produced in 1964 can still work 50 years later in 2014. No blown fuses, no electrolytics, no filaments, no f/w upgrades, no Y2K, no decaying EEPROM, no batteries, not even any IC's. No user s/w, no USB, no drivers, no OS. Not even an on/off switch! Just a 5-pin 24VDC backup or 2-prong AC cord in and a pure 5 MHz BNC out, that's all. How many of the instruments we use today will still work out-of-the-box in 2064? /tvb - Original Message - From: Richard (Rick) Karlquist rich...@karlquist.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Cc: hmur...@megapathdsl.net Sent: Wednesday, October 01, 2014 9:03 PM Subject: Re: [time-nuts] How long do ovens take to cool to ambient after power is removed? On 10/1/2014 1:04 PM, Hal Murray wrote: drkir...@kirkbymicrowave.co.uk said: Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. The question is though, how long is thing thing likely to take too cool? I'd expect an exponential decay so you need to specify how close to ambient you want to get. I'd guess a ballpark of 10x the warm up rate. You can probably measure it if you have the warmup graph. Turn it off, wait a while, turn it on, measure the freq, consult warmup graph. When I was still with Agilent, I did some experiments with unpowered 10811's. Both the oven and oscillator were unpowered and I measured the temperature by looking at the B mode resonance of the crystal. I wanted to get rid of any linear frequency drift. As a rough rule of thumb, 1 hour of cool down is pretty good for most purposes. For extreme measurements, I would allow 10 hours. This reduced any exponential tail to below the ability to measure temperature and/or below the effects of the ambient. I had to put a box over it to reduce the effects of air currents. If I did not do that, then 1 hour was all I needed. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?
Hi That 106 comes up *fast*. Take a look at the GR equivalent if you want to see slow….. Bob On Oct 2, 2014, at 2:58 PM, Tom Van Baak t...@leapsecond.com wrote: The most extreme example of slow ovenized oscillator warm-up I've seen is the vintage hp106. These mid-1960's oscillators were designed as the ultimate, hp way, pre-atomic, frequency standard -- expected to be powered up, uninterrupted, for years and decades. So there was no hurry in the (perhaps once-in-a-lifetime) initial warm-up. Here's a plot/photo of one I recently tested: http://leapsecond.com/museum/hp106a/ These HP-106 oscillators are among the best I have ever measured: stability and daily drift rates in the very low -13's. Like the SR-71, these were designed by gut and slide rule. And yet achieved extreme performance, even by today's standards. The amazing thing -- as you know from your enviable career at HP -- is that an instrument produced in 1964 can still work 50 years later in 2014. No blown fuses, no electrolytics, no filaments, no f/w upgrades, no Y2K, no decaying EEPROM, no batteries, not even any IC's. No user s/w, no USB, no drivers, no OS. Not even an on/off switch! Just a 5-pin 24VDC backup or 2-prong AC cord in and a pure 5 MHz BNC out, that's all. How many of the instruments we use today will still work out-of-the-box in 2064? /tvb - Original Message - From: Richard (Rick) Karlquist rich...@karlquist.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Cc: hmur...@megapathdsl.net Sent: Wednesday, October 01, 2014 9:03 PM Subject: Re: [time-nuts] How long do ovens take to cool to ambient after power is removed? On 10/1/2014 1:04 PM, Hal Murray wrote: drkir...@kirkbymicrowave.co.uk said: Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. The question is though, how long is thing thing likely to take too cool? I'd expect an exponential decay so you need to specify how close to ambient you want to get. I'd guess a ballpark of 10x the warm up rate. You can probably measure it if you have the warmup graph. Turn it off, wait a while, turn it on, measure the freq, consult warmup graph. When I was still with Agilent, I did some experiments with unpowered 10811's. Both the oven and oscillator were unpowered and I measured the temperature by looking at the B mode resonance of the crystal. I wanted to get rid of any linear frequency drift. As a rough rule of thumb, 1 hour of cool down is pretty good for most purposes. For extreme measurements, I would allow 10 hours. This reduced any exponential tail to below the ability to measure temperature and/or below the effects of the ambient. I had to put a box over it to reduce the effects of air currents. If I did not do that, then 1 hour was all I needed. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] How long do ovens take to cool to ambient after power is removed?
Following on from my question the other day about the type of oscillator in the HP 8720D VNA, I finally got around to setting this up on the spectrum analyzer today. Luckily, some software I wrote back in 2008 for a friends HP 7 system was easy to modify to grab the save the frequency. So I can now grab the data. I will post a plot later, once I have collected the data from a cold start. But it got me wondering, how long do ovens take to cool? I'm sure it must depend somewhat on the oven. According to someone on this list (sorry forget who), the option 1D5 is an oven, but not a particularly good one. Unfortunately he can't share the data he has on it, which is a bit annoying, but I understand his reasons. Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. The question is though, how long is thing thing likely to take too cool? My lab is air-conditioned, set at 23 deg C, though it varies about +/- 1.5 deg C from that. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?
Typical 10811 warm-up time is circa 10 minutes; cool-down time is actually several times longer (since there is no active cool-downer in the case!) More modern, smaller OCXO's will warm up and cool down more quickly. If it's a double oven or user has added extra insulation around the basic OCXO, the times have to get longer. I remember someone here wanting to put his OCXO in a Dewar. As we used to say at Caltech, Whatever fills your Dewar!. Not to be confused with bake out time! Tim N3QE On Wed, Oct 1, 2014 at 1:07 PM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: Following on from my question the other day about the type of oscillator in the HP 8720D VNA, I finally got around to setting this up on the spectrum analyzer today. Luckily, some software I wrote back in 2008 for a friends HP 7 system was easy to modify to grab the save the frequency. So I can now grab the data. I will post a plot later, once I have collected the data from a cold start. But it got me wondering, how long do ovens take to cool? I'm sure it must depend somewhat on the oven. According to someone on this list (sorry forget who), the option 1D5 is an oven, but not a particularly good one. Unfortunately he can't share the data he has on it, which is a bit annoying, but I understand his reasons. Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. The question is though, how long is thing thing likely to take too cool? My lab is air-conditioned, set at 23 deg C, though it varies about +/- 1.5 deg C from that. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?
drkir...@kirkbymicrowave.co.uk said: Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. The question is though, how long is thing thing likely to take too cool? I'd expect an exponential decay so you need to specify how close to ambient you want to get. I'd guess a ballpark of 10x the warm up rate. You can probably measure it if you have the warmup graph. Turn it off, wait a while, turn it on, measure the freq, consult warmup graph. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?
On 10/1/2014 1:04 PM, Hal Murray wrote: drkir...@kirkbymicrowave.co.uk said: Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. The question is though, how long is thing thing likely to take too cool? I'd expect an exponential decay so you need to specify how close to ambient you want to get. I'd guess a ballpark of 10x the warm up rate. You can probably measure it if you have the warmup graph. Turn it off, wait a while, turn it on, measure the freq, consult warmup graph. When I was still with Agilent, I did some experiments with unpowered 10811's. Both the oven and oscillator were unpowered and I measured the temperature by looking at the B mode resonance of the crystal. I wanted to get rid of any linear frequency drift. As a rough rule of thumb, 1 hour of cool down is pretty good for most purposes. For extreme measurements, I would allow 10 hours. This reduced any exponential tail to below the ability to measure temperature and/or below the effects of the ambient. I had to put a box over it to reduce the effects of air currents. If I did not do that, then 1 hour was all I needed. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?
I'd expect an exponential decay so you need to specify how close to ambient you want to get. I'd guess a ballpark of 10x the warm up rate. You can probably measure it if you have the warmup graph. Turn it off, wait a while, turn it on, measure the freq, consult warmup graph. Some older OCXO (like the 10544 and 10811) have separate power for the oscillator and oven(s) circuit. This makes it very easy to create comprehensive warm-up and warm-down plots in a single run. For modern oscillators with single supply, yeah, you sort of have to play the wait / power-on / quickly measure / power off / repeat game for every data point of the decay plot. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
