Re: [time-nuts] Maser manual
On Wed, 01 Sep 2010 22:37:36 -0700 jimlux jim...@earthlink.net wrote: J. Forster wrote: If you decide to go the zinc/acid route (a very bad idea, IMO) you will need a compressor. I'd not want anything to do with that! I like living. A Lecture Bottle is the way to go. Why would you compress it.. I imagine that you need micrograms of H2.. (it *is* almost a vacuum, right?).. And yes, zinc/acid probably is a bad way... How about electrolysis of distilled water. (I know you're not going to think that sodium/H2O is a good approach, eh?) In one of the papers i've read (which i'm currently unable to find), they used a electrolysis of KOH with a purifier. I don't know about KOH but NaOH is quite easy to get in large quantities. The only prob with it might be to keep it from taking too much water in. (on the other hand a lecture bottle is cheap and easy.. but this *is* time-nuts, where sometimes we like advocating the hard way... so what about some exotic nuclear reaction that throws off protons...I hesitate to suggest fissioning He, if it's even possible...) Single protons wont do it. The hyperfine line a H maser taps into is comes from the difference of the orientation of spins between the proton and its electron. And if i got it correctyl, you also have to make sure that the atom isn't excited in any way. Which isn't exactly easy if you start with a single proton and let it recombine with an electron. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] Maser manual
On Wed, 01 Sep 2010 20:08:13 + Poul-Henning Kamp p...@phk.freebsd.dk wrote: Yes, but what is the issues relating to sapphire loading? What's the cost of the sapphire block and having it machined? It is a saphire tube, a readily available, if not exactly cheap, commodity. Why saphir? Aluminia (AlO2) seems to be used as well to load H maser cavities. Or is saphir in some way better? Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] Off Topic in the Extreme
On Wed, 1 Sep 2010 12:36:22 -0400 Bob Camp li...@rtty.us wrote: I had an interesting conversation with an advanced tech support supervisor at Century Link / Embarq. According to this gentleman, their lines are only guaranteed to pass port 80 traffic (HTTP). Anything other than that is not covered by the service agreement. The only thing they will guarantee you can get to is their web site. Past that, if it's broke they have no responsibility what so ever for fixing it. That's not referring to port or traffic blocking. They all swear they don't and would never do that. If i had an ISP Tech telling me that they cannot guarranty that any IP traffic is going trough them correctly, i would imediatly switch to an other. What this guy was basically telling you is that they are traffic shaping, probably with some transparent proxy inbetween and are too cheap to tell you about it. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] Off Topic in the Extreme
On Wed, 1 Sep 2010 13:25:55 -0400 Bob Camp li...@rtty.us wrote: I suspect that it's not an unusual stance. If it is common, it would be something to think long and hard about in a mission critical timing setup. I don't know about the US, but in Europe such a stance would cost an ISP most of its customers, hence they cannot allow to say oh, it's not web, we dont guarranty anything if you are not using the web. It would be literally their death sentence. Usually, the ISPs here are more or less responsive on any issue a customer has. The smaller ones better than the bigger ones. Most probably because they know if the customer doesnt get what he wants, he'll switch to an other. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] Maser manual
In message 20100902082809.fff6c994.att...@kinali.ch, Attila Kinali writes: On Wed, 01 Sep 2010 22:37:36 -0700 In one of the papers i've read (which i'm currently unable to find), they used a electrolysis of KOH with a purifier. I don't know about KOH but NaOH is quite easy to get in large quantities. The only prob with it might be to keep it from taking too much water in. Normally you would use glaubersalt, (NA2SO4 I belive) to increase conductivity in small electrolysis setups, where you do not want any aggressive chemicals. If you are more tolerant, you simply add a couple of drops of sulfuric acid. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Maser manual
In message 20100902083014.d223768b.att...@kinali.ch, Attila Kinali writes: On Wed, 01 Sep 2010 20:08:13 + Poul-Henning Kamp p...@phk.freebsd.dk wrote: Why saphir? Aluminia (AlO2) seems to be used as well to load H maser cavities. Or is saphir in some way better? No idea, that's the paper I found... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Off Topic in the Extreme
I used to have a huge problem with my Comcast link going down (in Silicon Valley!), but they seem to be MUCH more reliable than a few years ago. The problem now appears to be very short outages, which seem to be caused by local cell interference with my wifi network. Still trying to figure it out. (ie- the stoppages in a streaming netflix movie appeared to be sometimes linked to local cell texting traffic) Go figure... Dave - Original Message - From: Attila Kinali att...@kinali.ch To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 2, 2010 12:36:56 AM Subject: Re: [time-nuts] Off Topic in the Extreme On Wed, 1 Sep 2010 13:25:55 -0400 Bob Camp li...@rtty.us wrote: I suspect that it's not an unusual stance. If it is common, it would be something to think long and hard about in a mission critical timing setup. I don't know about the US, but in Europe such a stance would cost an ISP most of its customers, hence they cannot allow to say oh, it's not web, we dont guarranty anything if you are not using the web. It would be literally their death sentence. Usually, the ISPs here are more or less responsive on any issue a customer has. The smaller ones better than the bigger ones. Most probably because they know if the customer doesnt get what he wants, he'll switch to an other. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] Maser info
John F., The Palladium valve is also known as a palladium leak or a palladium purifier. In the Maser the use is as the leak. It would also serve to purify the H2 BUT any other impurities lodge in the Palladium plug and can eventually cause it to fail. Early symptoms manifest as having to heat the plug to higher and higher temperatures to maintain the H2 flow. When the hydrogen bottle is changed you must perform a purge routine (see the manual) to allow any foreign gases to be removed. So for maximum life the Hydrogen should be as pure as possible. The resonator coil cannot be seen, I can see that it is a bit different than the manual shows. It was upgraded at some point. I can provide a picture of another masers coil. The receiving tank did not heat up all. Since I was going from a higher pressure tank to a mostly empty tank I don't think compression was involved Robert, You CANNOT use oil diffusion pumps, even for the rough pumping! (mechanical roughing pumps are also a no-no.) ANY contamination can seriously degrade the bulb coating. This can take quite a while to show up. Since tearing down the maser to replace the storage bulb is definitely NON-TRIVIAL. Using a turbo pump or vacsorbs are the only options. I use Vacsorbs as they are simple and quite a bit cheaper than the turbo. Bill, If your serious, the disassociator splits the hydrogen molecules H2 into atoms H to allow maser operation. I do have an old Interocitor screen I could mount on top of the Maser. It would look kinda neat! John M., The original oscillator was an upgrade and did not agree completely with the manuals schematic. I did get an updated schematic from the vendor and after much work and completely rebuilding it I still could not get it to work reliably. I decided to design my own using a low power oscillator to drive a power amplifier and impedance matching network. This has worked very well! Corby Dawson 1 Tip for Losing Weight Cut down 2 lbs per week by using this 1 weird old tip http://thirdpartyoffers.juno.com/TGL3141/4c7f52071849adf3adm04duc ___ 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] Maser manual
Attila Kinali wrote: On Wed, 01 Sep 2010 20:08:13 + Poul-Henning Kampp...@phk.freebsd.dk wrote: Yes, but what is the issues relating to sapphire loading? What's the cost of the sapphire block and having it machined? It is a saphire tube, a readily available, if not exactly cheap, commodity. Why saphir? Aluminia (AlO2) seems to be used as well to load H maser cavities. Or is saphir in some way better? Attila Kinali Sapphire and ruby are slightly impure varieties of corundum the single crystal form of aluminium oxide. Sapphire and rubies just have different inpurities that impart colour to the gem. The microwave loss in single crystal alumina (sapphire, corundum) may be somewhat lower than for the polycrystalline form. Bruce ___ 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] homebrew H maser
jimlux wrote: Hal Murray wrote: jim...@earthlink.net said: The gas diffusing out through the drilled bolt.. sure it's drilled, but the conductance is so patheticaly low, you're literally waiting until the gas molecules happen to randomly bounce their wey up the hole. I've never worked with vacuum gear. I assume drilled bolt refers to a bolt through a drilled hole so there is some slop between the bolt and the hole. No... the bolt has a hole through it, to provide a gas path when you install it into a blind tapped hole. Otherwise, the trapped gas in the bottom of the hole slowly leaks out past the threads. Can I use vacuum grease as a seal around the bolt? Or does it outgas too much if you are going for seriously low pressures? For the most part, grease is more trouble than it's worth. Knife edge seals are where it's at. Can I use a soft(er) metal washer and mash it to a gas tight fit by tightening the bolt enough? Not exactly.. what you see is a knife edge cutting into a softer metal... mashing implies gas trapped between layers.. That kind of thing crops up in TWT manufacturing, where they stack all the parts of the gun or the collector... How low a pressure does a H maser need? Where is it relative to say fingerprints outgassing? That's a good question.. I don't know. http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2doc=GetTRDoc.pdfAD=ADA503712 http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2doc=GetTRDoc.pdfAD=ADA503712 Indicates that the operating pressure at the hydrogen dissociator is likely to be a few Torr or so. Bruce ___ 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] Maser info
Higher operating temperatures force the use of nickel alloy to replace the silver palladium alloy traditionally used. At higher operating temperatures (40c and above) its not possible to turn off (without cooling it) the palladium leak. The Russian masers use nickel or nickel alloy instead of palladium or palladium silver. Bruce Corby Dawson wrote: John F., The Palladium valve is also known as a palladium leak or a palladium purifier. In the Maser the use is as the leak. It would also serve to purify the H2 BUT any other impurities lodge in the Palladium plug and can eventually cause it to fail. Early symptoms manifest as having to heat the plug to higher and higher temperatures to maintain the H2 flow. When the hydrogen bottle is changed you must perform a purge routine (see the manual) to allow any foreign gases to be removed. So for maximum life the Hydrogen should be as pure as possible. The resonator coil cannot be seen, I can see that it is a bit different than the manual shows. It was upgraded at some point. I can provide a picture of another masers coil. The receiving tank did not heat up all. Since I was going from a higher pressure tank to a mostly empty tank I don't think compression was involved Robert, You CANNOT use oil diffusion pumps, even for the rough pumping! (mechanical roughing pumps are also a no-no.) ANY contamination can seriously degrade the bulb coating. This can take quite a while to show up. Since tearing down the maser to replace the storage bulb is definitely NON-TRIVIAL. Using a turbo pump or vacsorbs are the only options. I use Vacsorbs as they are simple and quite a bit cheaper than the turbo. Bill, If your serious, the disassociator splits the hydrogen molecules H2 into atoms H to allow maser operation. I do have an old Interocitor screen I could mount on top of the Maser. It would look kinda neat! John M., The original oscillator was an upgrade and did not agree completely with the manuals schematic. I did get an updated schematic from the vendor and after much work and completely rebuilding it I still could not get it to work reliably. I decided to design my own using a low power oscillator to drive a power amplifier and impedance matching network. This has worked very well! Corby Dawson 1 Tip for Losing Weight Cut down 2 lbs per week by using this 1 weird old tip http://thirdpartyoffers.juno.com/TGL3141/4c7f52071849adf3adm04duc ___ 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] homebrew H maser
In message 4c7f5918.7030...@xtra.co.nz, Bruce Griffiths writes: Indicates that the operating pressure at the hydrogen dissociator is likely to be a few Torr or so. The pressure is basically: As low as possible in order to minimize hydrogen collisions (other hydrogen, walls) as much as possible. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Maser info
Reference for palladium-silver leak difficulty at high temperature. http://tycho.usno.navy.mil/ptti/1988/Vol%2020_10.pdf Bruce Bruce Griffiths wrote: Higher operating temperatures force the use of nickel alloy to replace the silver palladium alloy traditionally used. At higher operating temperatures (40c and above) its not possible to turn off (without cooling it) the palladium leak. The Russian masers use nickel or nickel alloy instead of palladium or palladium silver. Bruce Corby Dawson wrote: John F., The Palladium valve is also known as a palladium leak or a palladium purifier. In the Maser the use is as the leak. It would also serve to purify the H2 BUT any other impurities lodge in the Palladium plug and can eventually cause it to fail. Early symptoms manifest as having to heat the plug to higher and higher temperatures to maintain the H2 flow. When the hydrogen bottle is changed you must perform a purge routine (see the manual) to allow any foreign gases to be removed. So for maximum life the Hydrogen should be as pure as possible. The resonator coil cannot be seen, I can see that it is a bit different than the manual shows. It was upgraded at some point. I can provide a picture of another masers coil. The receiving tank did not heat up all. Since I was going from a higher pressure tank to a mostly empty tank I don't think compression was involved Robert, You CANNOT use oil diffusion pumps, even for the rough pumping! (mechanical roughing pumps are also a no-no.) ANY contamination can seriously degrade the bulb coating. This can take quite a while to show up. Since tearing down the maser to replace the storage bulb is definitely NON-TRIVIAL. Using a turbo pump or vacsorbs are the only options. I use Vacsorbs as they are simple and quite a bit cheaper than the turbo. Bill, If your serious, the disassociator splits the hydrogen molecules H2 into atoms H to allow maser operation. I do have an old Interocitor screen I could mount on top of the Maser. It would look kinda neat! John M., The original oscillator was an upgrade and did not agree completely with the manuals schematic. I did get an updated schematic from the vendor and after much work and completely rebuilding it I still could not get it to work reliably. I decided to design my own using a low power oscillator to drive a power amplifier and impedance matching network. This has worked very well! Corby Dawson 1 Tip for Losing Weight Cut down 2 lbs per week by using this 1 weird old tip http://thirdpartyoffers.juno.com/TGL3141/4c7f52071849adf3adm04duc ___ 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 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] homebrew H maser
Poul-Henning Kamp wrote: In message4c7f5918.7030...@xtra.co.nz, Bruce Griffiths writes: Indicates that the operating pressure at the hydrogen dissociator is likely to be a few Torr or so. The pressure is basically: As low as possible in order to minimize hydrogen collisions (other hydrogen, walls) as much as possible. i.e. the mean free path of the atomic hydrogen needs to be somewhat larger than the dimensions of the (fused silica) gas containment bulb. The mean free path will be comparable to the bulb dimensions at a pressure of around 1 ubar (100 uPa) or so. Since the Hydrogen atom bounces of the fluoropolymer coated walls thousands of times before phase coherence is lost the mean free path needs to be several thousand times the containment bulb dimensions to avoid degrading the maser performance. This requires a pressure of around 1 nanobar (100nPa) or below within the storage bulb.. The (gas) conductance of the exit aperture of the dissociator is selected to achieve the required atomic hydrogen flux of at most around 3E-5 liter-Torr/sec or so for a typical hydrogen dissociator pressure of 50Torr or so. Bruce ___ 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] homebrew H maser
Bruce Griffiths wrote: Poul-Henning Kamp wrote: In message4c7f5918.7030...@xtra.co.nz, Bruce Griffiths writes: Indicates that the operating pressure at the hydrogen dissociator is likely to be a few Torr or so. The pressure is basically: As low as possible in order to minimize hydrogen collisions (other hydrogen, walls) as much as possible. i.e. the mean free path of the atomic hydrogen needs to be somewhat larger than the dimensions of the (fused silica) gas containment bulb. The mean free path will be comparable to the bulb dimensions at a pressure of around 1 ubar (100 uPa) or so. Since the Hydrogen atom bounces of the fluoropolymer coated walls thousands of times before phase coherence is lost the mean free path needs to be several thousand times the containment bulb dimensions to avoid degrading the maser performance. This requires a pressure of around 1 nanobar (100nPa) or below within the storage bulb.. The (gas) conductance of the exit aperture of the dissociator is selected to achieve the required atomic hydrogen flux of at most around 3E-5 liter-Torr/sec or so for a typical hydrogen dissociator pressure of 50Torr or so. Bruce Oops!, the pressures given in Pa above are out a few orders of magnitude. Correct values are: The mean free path will be comparable to the bulb dimensions at a pressure of around 1 ubar (0.1Pa) or so. Since the Hydrogen atom bounces of the fluoropolymer coated walls thousands of times before phase coherence is lost the mean free path needs to be several thousand times the containment bulb dimensions to avoid degrading the maser performance. This requires a pressure of around 1 nanobar (100uPa) or below within the storage bulb.. The (gas) conductance of the exit aperture of the dissociator is selected to achieve the required atomic hydrogen flux of at most around 3E-5 liter-Torr/sec or so for a typical hydrogen dissociator pressure of 50Torr or so. Bruce ___ 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] Maser manual
Hi all, The Neuchatel MASER was build by Oscilloquartz in Neuchatel/Switzerland... Maybe somebody has the full coordinates of that :-) Oscilloquartz SA, http://www.oscilloquartz.com/ Brévards 16 2002 Neuchâtel Switzerland phone : +4132 722 fax : +4132 722 5556 Regards Karesz 2010/9/1 Magnus Danielson mag...@rubidium.dyndns.org: On 09/01/2010 09:39 PM, Poul-Henning Kamp wrote: In message24c547b54ea34a69bacc4f823bb40...@pc52, Tom Van Baak writes: I found the original copies of both EFOS manuals, along with a few photos. See: http://www.leapsecond.com/museum/efos/ Interesting. Page 4/3 in the service manual states: For the Hydrogen Maser, this unperturbed frequency is f(H) = 1 420 405 751.768 +/- 0.002 Hz In practice, this frequency is perturbed by interaction of the hydrogen atoms with the walls of the interaction volume container, doppler effects, interactions between the atoms themsel- ves, etc. The resulting frequency for the EFOS Maser is taken to be F(o) = 1 420 405 751.689 Hz I have no idea where the EFOS was produced, but somebody should try to calculate the relativistic correction for their height above the geoid, and see how much of the systematic 0.079Hz frequency difference that explains... Neuchatel, which still leaves a bit of unspecified height. However, this effect would be cancelled as their cesium clocks would be on the same height above the geoid (give or take a few meters). So, their indication is correct. The C-field also pulls the atoms of course, which they failed to point out in the cited text. If I were to build a maser myself, I would probably not attempt to copy the EFOS, as the large mechanical dimensions add significant cost in materials and machining. I would be much more tempted by a sapphire loaded cavity design like this one: http://www.nict.go.jp/publication/shuppan/kihou-journal/journal-vol50no1.2/0304.pdf) As that brings the mechanics inside the work envelope of main-stream CNC machines with the required tolerances. Yes, but what is the issues relating to sapphire loading? What's the cost of the sapphire block and having it machined? 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. ___ 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] Off Topic in the Extreme
With Verizon Fios, I have had several instances where a storm has knocked out my internet, yet my phone, which uses the same fiber, still works. (Yes, my router was on an ups, and yes the power was on...) The internet usually comes back in a day, or so. Because they have seriously limited the amount of fiber that goes above ground, in my area, the phone hasn't gone down since the fiber went in. -Chuck Harris Max Robinson wrote: I noticed that after I hooked up my phone to the cable company my computer connection became a lot more reliable. Both pass through the same modem. In fact it has not been off since the hookup. I think they do try very hard to keep the computer path on for those who also have the phone service. We also have a minimum cost cell phone for emergencies both in the car or at home. Regards. ___ 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] Maser manual
jimlux wrote: paul swed wrote: So by those pictures you actually have it working? Crazy question do you just drive down to your local air gas company and by some hydrogen. How do you fill the red bottle? Just down loaded the tech manual earlier printed out the ops manual. Thanks Basically, yes.. you can order up a tank of H2 pretty easily. However, I would think you need a fairly pure grade (e.g. oxyhydrogen welding grade aint gonna cut it).. For small amounts, a lecture bottle (2 cu ft at STP) would probably be the way to go. Or, generate it yourself (zinc and acid, for instance) That won't make pure H2, it will be loaded with water, and acid fumes. You will have to apply the same techniques to clean H2 made that way as you would need to use to clean welding grade H2. A nice cryotrap would probably do the trick. -Chuck Harris ___ 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] Off Topic in the Extreme
Hi The troubling part of my situation with Century / Embarq is that a hacked router in their plant, doing port forwarding poorly, would do create the issue I saw. The question now is - did they fix it or did the guy doing the forwarding fix his bug? In my case he's going to be sifting through a lot of spam and mailing lists to find anything useful. If it was a security breach, knowing about it would allow people to at least consider what might have been compromised. Since they have only one network, a problem or hole in the residential network is no different than one in the business network. Other than last mile issues, fixing one fixes the other. If people are poking holes in their network, they could just as easily play with timing traffic as anything else. I wonder if there are any bank vaults running on NTP time? Probably not. Lots of bank computers on NTP, and far more money in the computer than the vault. Bob On Sep 2, 2010, at 12:41 AM, jimlux jim...@earthlink.net wrote: Didier Juges wrote: Not unlike Cox. They generally provide great service, but when problems do crop up (rare, but it has happened), the only thing that they guaranty is that you will get their bill in the mail on time. Any more than that is just gravy... Didier This is the fundamental difference between consumer service and business service. Yes, one pays more for the business service, but there's also none of this best efforts nonsense.. They say, we pass X traffic at Y bits per second, and if it breaks, we'll fix it within Z hours, etc. It's also why, ultimately, the phone company (even the unregulated data services side) is generally better than the cable TV company...It's a mindset thing. The folks maintaining the physical plant for the former have a keep the lights on at all cost mindset. .The folks maintaining the physical plant for the latter have a well. if it breaks, you're just not being entertained, so we'll rebate a days worth of entertainment on your next bill The VoIP folks over cable will get their mindset straight after a few spectacular I tried to call 911 but the cable was out events. ___ 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] Off Topic in the Extreme
Hi The cable company can play games on their end to significantly impact what you get at the modem. Bob On Sep 2, 2010, at 12:53 AM, Max Robinson m...@maxsmusicplace.com wrote: I noticed that after I hooked up my phone to the cable company my computer connection became a lot more reliable. Both pass through the same modem. In fact it has not been off since the hookup. I think they do try very hard to keep the computer path on for those who also have the phone service. We also have a minimum cost cell phone for emergencies both in the car or at home. Regards. Max. K 4 O D S. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com - Original Message - From: jimlux jim...@earthlink.net To: did...@cox.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, September 01, 2010 11:41 PM Subject: Re: [time-nuts] Off Topic in the Extreme Didier Juges wrote: Not unlike Cox. They generally provide great service, but when problems do crop up (rare, but it has happened), the only thing that they guaranty is that you will get their bill in the mail on time. Any more than that is just gravy... Didier This is the fundamental difference between consumer service and business service. Yes, one pays more for the business service, but there's also none of this best efforts nonsense.. They say, we pass X traffic at Y bits per second, and if it breaks, we'll fix it within Z hours, etc. It's also why, ultimately, the phone company (even the unregulated data services side) is generally better than the cable TV company...It's a mindset thing. The folks maintaining the physical plant for the former have a keep the lights on at all cost mindset. .The folks maintaining the physical plant for the latter have a well. if it breaks, you're just not being entertained, so we'll rebate a days worth of entertainment on your next bill The VoIP folks over cable will get their mindset straight after a few spectacular I tried to call 911 but the cable was out events. ___ 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 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] Off Topic in the Extreme
Hi What the guy was telling me was that they don't want customers who care if there's a connection or not. Since I do care, I won't be a Century Tel. customer much longer. I would have switched on the spot, but reprograming the routers takes a bit of time. Cisco IOS isn't my favorite thing to code in Bob On Sep 2, 2010, at 2:33 AM, Attila Kinali att...@kinali.ch wrote: On Wed, 1 Sep 2010 12:36:22 -0400 Bob Camp li...@rtty.us wrote: I had an interesting conversation with an advanced tech support supervisor at Century Link / Embarq. According to this gentleman, their lines are only guaranteed to pass port 80 traffic (HTTP). Anything other than that is not covered by the service agreement. The only thing they will guarantee you can get to is their web site. Past that, if it's broke they have no responsibility what so ever for fixing it. That's not referring to port or traffic blocking. They all swear they don't and would never do that. If i had an ISP Tech telling me that they cannot guarranty that any IP traffic is going trough them correctly, i would imediatly switch to an other. What this guy was basically telling you is that they are traffic shaping, probably with some transparent proxy inbetween and are too cheap to tell you about it. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] homebrew H maser
Poul-Henning Kamp wrote: In message 4c7f5918.7030...@xtra.co.nz, Bruce Griffiths writes: Indicates that the operating pressure at the hydrogen dissociator is likely to be a few Torr or so. The pressure is basically: As low as possible in order to minimize hydrogen collisions (other hydrogen, walls) as much as possible. A few torr is actually not a particularly high vacuum (e.g. your run of the mill neon sign is pumped down a lot lower before being filled to a few torr). PHKs comment implies you're looking for mean free path somewhat greater than physical dimensions... That would imply pressures less than a micron (0.001 Torr).. MFP = 5E-3/P with P in Torr.. 1 micron pressure == 5cm MFP The other thing is when you're looking at MFP comparable to dimensions, you're looking at molecular pumping in some form (no more pistons or rotary vanes or ...) ___ 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] Choice of MASER gas
John Miles brought up an interesting question that got lost in the discussion of high vacuum systems: what about the choice of gas? Besides H, there is a dual Xe/He system detailed in: http://www.cfa.harvard.edu/Walsworth/pdf/Bear%20thesis.pdf And, as mentioned before, Harvard has built Rb masers: http://cfa-www.harvard.edu/~dphil/work/coat.pdfhttp://cfa-www.harvard.edu/%7Edphil/work/coat.pdf http://cfa-www.harvard.edu/%7Edphil/work/coat.pdf And John mentioned HN3 masers (advantage: you would be able to smell the leak!). ___ 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] Off Topic in the Extreme
Hi In this case the company is the legacy monopoly wire line carrier for this area. If you want coper wires you go to them. There is no other choice. They do what ever the government regulators make them do. The supervisor referred to those regulations in about every third sentence. Century and Embarq were two separate companies until fairly recently. They obviously are having a tough time getting things stitched together. Both were relatively small outfits and the combination is still pretty small. Their footprint covers a lot of farms and not many big urban areas. The net result is that most of their customers have no real choice in suppliers. Unless they live 18 minutes from the state capital they have little ability to interact with the regulators. Of course the lucky few who do live close to the capital and who do have choices Bob On Sep 2, 2010, at 2:36 AM, Attila Kinali att...@kinali.ch wrote: On Wed, 1 Sep 2010 13:25:55 -0400 Bob Camp li...@rtty.us wrote: I suspect that it's not an unusual stance. If it is common, it would be something to think long and hard about in a mission critical timing setup. I don't know about the US, but in Europe such a stance would cost an ISP most of its customers, hence they cannot allow to say oh, it's not web, we dont guarranty anything if you are not using the web. It would be literally their death sentence. Usually, the ISPs here are more or less responsive on any issue a customer has. The smaller ones better than the bigger ones. Most probably because they know if the customer doesnt get what he wants, he'll switch to an other. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] Maser manual (2)
If the thing has a variable cap to tune the osc. My bet is thats the devil. In cheapy telco RBs they have given me lots of trouble. On Wed, Sep 1, 2010 at 11:40 PM, John Miles jmi...@pop.net wrote: Good point -- I should swap out the feedthrough as well. There is only one in this case, for the power lead-in, but if it is growing internal whiskers or otherwise failing I could see it causing this symptom... -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Kit Scally Sent: Wednesday, September 01, 2010 8:34 PM To: time-nuts@febo.com Subject: [time-nuts] Maser manual (2) John, I'd put money on one of the feedthrough caps (easily damaged upon installation) in the Maser for such small jumps. From memory, the 5065A uses SM components, but these could be guilty. I've learned many abstract things I'd never otherwise come across in this thread on home-built masers. I for one would like to see more mileage on this topic although I'm not sure there's $25k in my Xmas box for the necessary parts to build one ! Kit VK2LL snip The 5065A is showing occasional phase jumps on the order of 10-100 ps that coincide with small spikes in the current drawn by the lamp exciter, and I'm leaning towards blaming the silver-mica B-E feedback capacitor. (It even has the same designation in both instruments' service manuals, C2.) Tom: this is why your BVA was appearing to jump when I measured it. :-P -- john, KE5FX snip ___ 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 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] Off Topic in the Extreme
Hi If your WiFi is at 2.4 GHz it could very easily be a microwave oven messing things up. Bob On Sep 2, 2010, at 3:12 AM, d.sei...@comcast.net wrote: I used to have a huge problem with my Comcast link going down (in Silicon Valley!), but they seem to be MUCH more reliable than a few years ago. The problem now appears to be very short outages, which seem to be caused by local cell interference with my wifi network. Still trying to figure it out. (ie- the stoppages in a streaming netflix movie appeared to be sometimes linked to local cell texting traffic) Go figure... Dave - Original Message - From: Attila Kinali att...@kinali.ch To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 2, 2010 12:36:56 AM Subject: Re: [time-nuts] Off Topic in the Extreme On Wed, 1 Sep 2010 13:25:55 -0400 Bob Camp li...@rtty.us wrote: I suspect that it's not an unusual stance. If it is common, it would be something to think long and hard about in a mission critical timing setup. I don't know about the US, but in Europe such a stance would cost an ISP most of its customers, hence they cannot allow to say oh, it's not web, we dont guarranty anything if you are not using the web. It would be literally their death sentence. Usually, the ISPs here are more or less responsive on any issue a customer has. The smaller ones better than the bigger ones. Most probably because they know if the customer doesnt get what he wants, he'll switch to an other. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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 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] Maser manual
So, the see of Neuchatel has 429 meter o.NN, the city of Neuchatel/Neuenburg is on so 430-470m. Somebody can calculate yet a correction - if needed/likes... K. 2010/9/2 K. Szeker szeke...@gmail.com: I have the coodinates yet too(but not the hight over see): 46.991347,6.913806 regards 2010/9/2 K. Szeker szeke...@gmail.com: Hi all, The Neuchatel MASER was build by Oscilloquartz in Neuchatel/Switzerland... Maybe somebody has the full coordinates of that :-) Oscilloquartz SA, http://www.oscilloquartz.com/ Brévards 16 2002 Neuchâtel Switzerland phone : +4132 722 fax : +4132 722 5556 Regards Karesz 2010/9/1 Magnus Danielson mag...@rubidium.dyndns.org: On 09/01/2010 09:39 PM, Poul-Henning Kamp wrote: In message24c547b54ea34a69bacc4f823bb40...@pc52, Tom Van Baak writes: I found the original copies of both EFOS manuals, along with a few photos. See: http://www.leapsecond.com/museum/efos/ Interesting. Page 4/3 in the service manual states: For the Hydrogen Maser, this unperturbed frequency is f(H) = 1 420 405 751.768 +/- 0.002 Hz In practice, this frequency is perturbed by interaction of the hydrogen atoms with the walls of the interaction volume container, doppler effects, interactions between the atoms themsel- ves, etc. The resulting frequency for the EFOS Maser is taken to be F(o) = 1 420 405 751.689 Hz I have no idea where the EFOS was produced, but somebody should try to calculate the relativistic correction for their height above the geoid, and see how much of the systematic 0.079Hz frequency difference that explains... Neuchatel, which still leaves a bit of unspecified height. However, this effect would be cancelled as their cesium clocks would be on the same height above the geoid (give or take a few meters). So, their indication is correct. The C-field also pulls the atoms of course, which they failed to point out in the cited text. If I were to build a maser myself, I would probably not attempt to copy the EFOS, as the large mechanical dimensions add significant cost in materials and machining. I would be much more tempted by a sapphire loaded cavity design like this one: http://www.nict.go.jp/publication/shuppan/kihou-journal/journal-vol50no1.2/0304.pdf) As that brings the mechanics inside the work envelope of main-stream CNC machines with the required tolerances. Yes, but what is the issues relating to sapphire loading? What's the cost of the sapphire block and having it machined? 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. ___ 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] homebrew H maser
Hi Also to pump the beast clean after you have opened it up Bob On Sep 2, 2010, at 4:04 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 4c7f5918.7030...@xtra.co.nz, Bruce Griffiths writes: Indicates that the operating pressure at the hydrogen dissociator is likely to be a few Torr or so. The pressure is basically: As low as possible in order to minimize hydrogen collisions (other hydrogen, walls) as much as possible. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] homebrew H maser
Hi That pressure level pretty much rules out mechanical pumps for the operating mode. A roughing pump would still be needed to get things going. It also takes the level of machining on the fittings well beyond the reach of most machine shops. Some of the stuff has to be exact, close to a tolerance won't do the trick. Bob On Sep 2, 2010, at 4:39 AM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Bruce Griffiths wrote: Poul-Henning Kamp wrote: In message4c7f5918.7030...@xtra.co.nz, Bruce Griffiths writes: Indicates that the operating pressure at the hydrogen dissociator is likely to be a few Torr or so. The pressure is basically: As low as possible in order to minimize hydrogen collisions (other hydrogen, walls) as much as possible. i.e. the mean free path of the atomic hydrogen needs to be somewhat larger than the dimensions of the (fused silica) gas containment bulb. The mean free path will be comparable to the bulb dimensions at a pressure of around 1 ubar (100 uPa) or so. Since the Hydrogen atom bounces of the fluoropolymer coated walls thousands of times before phase coherence is lost the mean free path needs to be several thousand times the containment bulb dimensions to avoid degrading the maser performance. This requires a pressure of around 1 nanobar (100nPa) or below within the storage bulb.. The (gas) conductance of the exit aperture of the dissociator is selected to achieve the required atomic hydrogen flux of at most around 3E-5 liter-Torr/sec or so for a typical hydrogen dissociator pressure of 50Torr or so. Bruce Oops!, the pressures given in Pa above are out a few orders of magnitude. Correct values are: The mean free path will be comparable to the bulb dimensions at a pressure of around 1 ubar (0.1Pa) or so. Since the Hydrogen atom bounces of the fluoropolymer coated walls thousands of times before phase coherence is lost the mean free path needs to be several thousand times the containment bulb dimensions to avoid degrading the maser performance. This requires a pressure of around 1 nanobar (100uPa) or below within the storage bulb.. The (gas) conductance of the exit aperture of the dissociator is selected to achieve the required atomic hydrogen flux of at most around 3E-5 liter-Torr/sec or so for a typical hydrogen dissociator pressure of 50Torr or so. Bruce ___ 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] homebrew H maser
This discussion reminds me of a time long ago when I worked at a University. We had one rather obnoxious Grad Student, who, although brilliant, was a Royal PITA. So, while constructing his vacuum system, and getting hassled by him, I located one of the Universities residents, a large water bug. Which I let loose in the vacuum plumbing. He was beside himself for about a week, wondering why he could not get pumped down to the level he expected. 73, Dick, W1KSZ -Original Message- From: jimlux jim...@earthlink.net Sent: Sep 2, 2010 6:29 AM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] homebrew H maser Poul-Henning Kamp wrote: In message 4c7f5918.7030...@xtra.co.nz, Bruce Griffiths writes: Indicates that the operating pressure at the hydrogen dissociator is likely to be a few Torr or so. The pressure is basically: As low as possible in order to minimize hydrogen collisions (other hydrogen, walls) as much as possible. A few torr is actually not a particularly high vacuum (e.g. your run of the mill neon sign is pumped down a lot lower before being filled to a few torr). PHKs comment implies you're looking for mean free path somewhat greater than physical dimensions... That would imply pressures less than a micron (0.001 Torr).. MFP = 5E-3/P with P in Torr.. 1 micron pressure == 5cm MFP The other thing is when you're looking at MFP comparable to dimensions, you're looking at molecular pumping in some form (no more pistons or rotary vanes or ...) ___ 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] Maser info
If your serious, the disassociator splits the hydrogen molecules H2 into atoms H to allow maser operation. I do have an old Interocitor screen I could mount on top of the Maser. It would look kinda neat! Oh Corby, you are a man of true wit. I love it Hadley A fine is a tax for doing wrong. A tax is a fine for doing well. Peter Cooper, of Fermi Lab, says, Every experimentalist knows that the apparatus, or at least your understanding of it, is always at fault until demonstrated otherwise. He also says, Nature is really unmoved by what I, or anyone else, believes. ___ 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] Off Topic in the Extreme - microwave oven and WiFi
My uW oven does that very well, but not consistently. It occasionally kicks my laptop off line, but not every time. The oven frequency is not very stable and it needs the right combination of temperature and phase of the moon to be exactly at the bad spot long enough to disconnect. You also have to be close enough. Example: I routinely warm a cup of coffee (35 seconds :) in the microwave oven in the morning while I have Skype video running on the laptop in the kitchen. The router is way at the other end of the house, so signal is low and it is a worst case situation. If I put the laptop about 10 feet from the oven, it gets knocked off every 2-3 times, if I put it 20 feet away, it's all good. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Bob Camp li...@rtty.us Sender: time-nuts-boun...@febo.com Date: Thu, 2 Sep 2010 09:36:40 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Off Topic in the Extreme Hi If your WiFi is at 2.4 GHz it could very easily be a microwave oven messing things up. Bob On Sep 2, 2010, at 3:12 AM, d.sei...@comcast.net wrote: I used to have a huge problem with my Comcast link going down (in Silicon Valley!), but they seem to be MUCH more reliable than a few years ago. The problem now appears to be very short outages, which seem to be caused by local cell interference with my wifi network. Still trying to figure it out. (ie- the stoppages in a streaming netflix movie appeared to be sometimes linked to local cell texting traffic) Go figure... Dave - Original Message - From: Attila Kinali att...@kinali.ch To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 2, 2010 12:36:56 AM Subject: Re: [time-nuts] Off Topic in the Extreme On Wed, 1 Sep 2010 13:25:55 -0400 Bob Camp li...@rtty.us wrote: I suspect that it's not an unusual stance. If it is common, it would be something to think long and hard about in a mission critical timing setup. I don't know about the US, but in Europe such a stance would cost an ISP most of its customers, hence they cannot allow to say oh, it's not web, we dont guarranty anything if you are not using the web. It would be literally their death sentence. Usually, the ISPs here are more or less responsive on any issue a customer has. The smaller ones better than the bigger ones. Most probably because they know if the customer doesnt get what he wants, he'll switch to an other. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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 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] Off Topic in the Extreme
I can't resist a chance for a minor rant. Our neighborhood has suffered for years with noisy land line phone service and occasional outages. They are caused by degraded underground cables. Usually worse in the winter when moisture gets into things, but my phone is presently so noisy I can barely use it. Two repairmen came out, couldn't fix it and passed the problem on to Maintenance. I think that department is in charge of maintaining the noise. Bob -- From: Bob Camp li...@rtty.us Sent: Wednesday, September 01, 2010 9:36 AM To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Subject: [time-nuts] Off Topic in the Extreme Hi Back up again on email. It's completely unclear who or what took things down. It's also unclear what fixed it. All I can be sure of is I neither broke it or fixed it. It came back up today at around 10. I had an interesting conversation with an advanced tech support supervisor at Century Link / Embarq. According to this gentleman, their lines are only guaranteed to pass port 80 traffic (HTTP). Anything other than that is not covered by the service agreement. The only thing they will guarantee you can get to is their web site. Past that, if it's broke they have no responsibility what so ever for fixing it. That's not referring to port or traffic blocking. They all swear they don't and would never do that. Since timing and the like are going to things other than port 80, and using protocols other than http does, I assume his statements = no timing traffic support. The guy could easily have been mistaken, that sort of thing does happen around midnight. If what he said is true, any sort of system that relied on their network for time would be *very* much in trouble if something subtle broke. Being broke in a way that passes one thing and not another is unusual, but not impossible. Crazy stuff .. Bob ___ 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. __ Information from ESET NOD32 Antivirus, version of virus signature database 5413 (20100831) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __ Information from ESET NOD32 Antivirus, version of virus signature database 5416 (20100901) __ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ___ 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] WeirdStuff tbolt $75
WeirdStuff has tbolts, no case, no info about firmware version, for $75. They were $495 but I sent them a note saying it wasn't a competitive price and they lowered it and they appear to be selling out quickly. http://www.weirdstuff.com/cgi-bin/category.cgi?item=29654 Also on their weirdstuff-inc ebay store for the so inclined. Leigh/WA5ZNU ___ 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] WeirdStuff tbolt $75
They appear to be gone now. -Bob On Thu, Sep 2, 2010 at 10:06 AM, Leigh L. Klotz, Jr WA5ZNU le...@wa5znu.org wrote: WeirdStuff has tbolts, no case, no info about firmware version, for $75. They were $495 but I sent them a note saying it wasn't a competitive price and they lowered it and they appear to be selling out quickly. http://www.weirdstuff.com/cgi-bin/category.cgi?item=29654 Also on their weirdstuff-inc ebay store for the so inclined. Leigh/WA5ZNU ___ 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] WeirdStuff tbolt $75
Sorry, the link showed nothing. They are still on the eBay store. more than 10 available at the time of this writing. -Bob On Thu, Sep 2, 2010 at 10:40 AM, Robert Darlington rdarling...@gmail.comwrote: They appear to be gone now. -Bob On Thu, Sep 2, 2010 at 10:06 AM, Leigh L. Klotz, Jr WA5ZNU le...@wa5znu.org wrote: WeirdStuff has tbolts, no case, no info about firmware version, for $75. They were $495 but I sent them a note saying it wasn't a competitive price and they lowered it and they appear to be selling out quickly. http://www.weirdstuff.com/cgi-bin/category.cgi?item=29654 Also on their weirdstuff-inc ebay store for the so inclined. Leigh/WA5ZNU ___ 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] WeirdStuff tbolt $75
And we should not forget the extra expensive Shipping: $105.35 UPS Worldwide Express too... K. 2010/9/2 Leigh L. Klotz, Jr WA5ZNU le...@wa5znu.org: WeirdStuff has tbolts, no case, no info about firmware version, for $75. They were $495 but I sent them a note saying it wasn't a competitive price and they lowered it and they appear to be selling out quickly. http://www.weirdstuff.com/cgi-bin/category.cgi?item=29654 Also on their weirdstuff-inc ebay store for the so inclined. Leigh/WA5ZNU ___ 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] Fwd: Re: homebrew H maser
Metal diaphragm rough, sorbtion, then Ion is the way to go, IMO. You only need LN2 to run the sorbtion until you get into the Ion range, then you valve the sorbtion off. Cryopumps are a PITA, IMO. FWIW, -John == Bob Camp wrote: Hi My guess is that you either need a cryo pump or ion pumps and a very good seal. Bob You know.. a cryo/sorption pump might be the way to go. Easy to use (just get some LN2) and they can pump down pretty fast. If you only need one or two pumpdown cycles, that might be the ticket. theBellJar had a whole thing on homemade cryo pumps using stuff like pickle jars.. ___ 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] homebrew H maser
jim...@earthlink.net said: The gas diffusing out through the drilled bolt.. sure it's drilled, but the conductance is so patheticaly low, you're literally waiting until the gas molecules happen to randomly bounce their wey up the hole. I've never worked with vacuum gear. I assume drilled bolt refers to a bolt through a drilled hole so there is some slop between the bolt and the hole. No. It's used where a bolt goes into a blind hole. It is to vent the trapped gas more quickly to reduce virtual leaks Can I use vacuum grease as a seal around the bolt? Or does it outgas too much if you are going for seriously low pressures? Basically no. SS bolts are lubed to prevent sieze up, but not in vacuum. Can I use a soft(er) metal washer and mash it to a gas tight fit by tightening the bolt enough? Conflat (and other) fittings use OHFC copper gaskets (one use only. Take it appart and you must use new ones). Also Indium and Gold are used. How low a pressure does a H maser need? Where is it relative to say fingerprints outgassing? The vacuum areas must be really clean. Think vapor degreasing with Trichlor. Is there an easy to understand scale of difficulty? (like dishes rattle for the Richter scale) On a scale of 1 to 10: 1 getting a GPS DO working. 3 getting a Rb working from scratch. 9 getting a H2 MASER working scratch. 15+ getting an Ion trap working. And, like the Richter, this is a log scale. FWIW, -John == -- These are my opinions, not necessarily my employer's. 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. ___ 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] WeirdStuff tbolt $75
Umm, their eBay listing shows like $11 for US domestic shipping and $30 to Turkmenistan...seems pretty in line with reality... -Pete On 09/02/2010 09:49 AM, K. Szeker wrote: And we should not forget the extra expensive Shipping:$105.35 UPS Worldwide Express too... K. 2010/9/2 Leigh L. Klotz, Jr WA5ZNUle...@wa5znu.org: WeirdStuff has tbolts, no case, no info about firmware version, for $75. They were $495 but I sent them a note saying it wasn't a competitive price and they lowered it and they appear to be selling out quickly. http://www.weirdstuff.com/cgi-bin/category.cgi?item=29654 Also on their weirdstuff-inc ebay store for the so inclined. Leigh/WA5ZNU ___ 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 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] WeirdStuff tbolt $75 [eBay Link]
Just to remove a variable seemingly causing confusion; The ebay link is http://cgi.ebay.com/300457580821 And still more than 10 available. On 9/2/2010 12:02 PM, Peter Loron wrote: Umm, their eBay listing shows like $11 for US domestic shipping and $30 to Turkmenistan...seems pretty in line with reality... -Pete -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ 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] WeirdStuff tbolt $75
Hi Peter, You are right, in the text/details are, for same destination, more moderate prices too Under the cover shipments costs was the expensivste to see... US $105,35 Deutschland UPS Worldwide ExpressSM US $96,97 Deutschland UPS Worldwide ExpeditedSM US $31,05 Deutschland USPS Priority Mail InternationalTM Greetings! Karesz 2010/9/2 Peter Loron pet...@standingwave.org: Umm, their eBay listing shows like $11 for US domestic shipping and $30 to Turkmenistan...seems pretty in line with reality... -Pete On 09/02/2010 09:49 AM, K. Szeker wrote: And we should not forget the extra expensive Shipping: $105.35 UPS Worldwide Express too... K. 2010/9/2 Leigh L. Klotz, Jr WA5ZNUle...@wa5znu.org: WeirdStuff has tbolts, no case, no info about firmware version, for $75. They were $495 but I sent them a note saying it wasn't a competitive price and they lowered it and they appear to be selling out quickly. http://www.weirdstuff.com/cgi-bin/category.cgi?item=29654 Also on their weirdstuff-inc ebay store for the so inclined. Leigh/WA5ZNU ___ 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 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] Maser manual
On Wed, 01 Sep 2010 22:37:36 -0700 jimlux jim...@earthlink.net wrote: J. Forster wrote: If you decide to go the zinc/acid route (a very bad idea, IMO) you will need a compressor. I'd not want anything to do with that! I like living. A Lecture Bottle is the way to go. Why would you compress it.. I imagine that you need micrograms of H2.. (it *is* almost a vacuum, right?).. You need a pressure differential across the Palladium plug used to control the H2 flow into the MASER. At a first glance the 1 Atm seems too low, but might be enough if you heat the Palladium hot enough. It's an engineering tradeoff and I've not done the analysis. Comment: When contemplating something like making a MASER, you want to buy things off the shelf, if at all possible. I'd buy a Lecture Bottle of H2 and a regulator for $100 or so and move on to the next step. It's not an exercise in building a working unit on a desert island from sand and coconut shells. And yes, zinc/acid probably is a bad way... How about electrolysis of distilled water. (I know you're not going to think that sodium/H2O is a good approach, eh?) In one of the papers i've read (which i'm currently unable to find), they used a electrolysis of KOH with a purifier. I don't know about KOH but NaOH is quite easy to get in large quantities. The only prob with it might be to keep it from taking too much water in. (on the other hand a lecture bottle is cheap and easy.. but this *is* time-nuts, where sometimes we like advocating the hard way... so what about some exotic nuclear reaction that throws off protons...I hesitate to suggest fissioning He, if it's even possible...) Single protons wont do it. The hyperfine line a H maser taps into is comes from the difference of the orientation of spins between the proton and its electron. And if i got it correctyl, you also have to make sure that the atom isn't excited in any way. Which isn't exactly easy if you start with a single proton and let it recombine with an electron. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] homebrew H maser
I am rally interested to be part of a team of people with the target to built an active H Maser. If there are in the world persons who are really interested in, it will be a good starting point. To built specific parts there are several way to do it in ham saving mode, for example for the cavity I can find a friend of main that have high precision machine to phisically prepare it and so on. First of all is important to find the team. Hope hear you, Luciano P. S. Paramithiotti -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: giovedì 2 settembre 2010 18.59 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] homebrew H maser jim...@earthlink.net said: The gas diffusing out through the drilled bolt.. sure it's drilled, but the conductance is so patheticaly low, you're literally waiting until the gas molecules happen to randomly bounce their wey up the hole. I've never worked with vacuum gear. I assume drilled bolt refers to a bolt through a drilled hole so there is some slop between the bolt and the hole. No. It's used where a bolt goes into a blind hole. It is to vent the trapped gas more quickly to reduce virtual leaks Can I use vacuum grease as a seal around the bolt? Or does it outgas too much if you are going for seriously low pressures? Basically no. SS bolts are lubed to prevent sieze up, but not in vacuum. Can I use a soft(er) metal washer and mash it to a gas tight fit by tightening the bolt enough? Conflat (and other) fittings use OHFC copper gaskets (one use only. Take it appart and you must use new ones). Also Indium and Gold are used. How low a pressure does a H maser need? Where is it relative to say fingerprints outgassing? The vacuum areas must be really clean. Think vapor degreasing with Trichlor. Is there an easy to understand scale of difficulty? (like dishes rattle for the Richter scale) On a scale of 1 to 10: 1 getting a GPS DO working. 3 getting a Rb working from scratch. 9 getting a H2 MASER working scratch. 15+ getting an Ion trap working. And, like the Richter, this is a log scale. FWIW, -John == -- These are my opinions, not necessarily my employer's. 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. ___ 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] Maser info (vacuum levels)
This EFOS maser typically runs with the two vacuum pressures below 1.5 X 10-6 Torr. (as measured via the ion pump current) Maximum should not exceed about 3.6 X 10-6 Torr for either pump. The internal vacuum will drop to about 1 X10-7 Torr if the Hydrogen to the disassociator is turned off. One pump pumps the internal which is the maser bulb, the disassociator, and the connecting lines, so mainly just pumps Hydrogen. (fairly low volume) The external pump pumps the insulating outer shell and the interior of the maser cavity. It pumps any leakage or outgassing that occurs. (much larger volume) Pumps are 20 LPS varian triodes. Corby Dawson Moms Asked to Return to School Grant Funding May Be Available to Those That Qualify. http://thirdpartyoffers.juno.com/TGL3141/4c7fdedb5d30e0abfm04duc ___ 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] Maser info
John F., The Palladium valve is also known as a palladium leak or a palladium purifier. In the Maser the use is as the leak. It would also serve to purify the H2 BUT any other impurities lodge in the Palladium plug and can eventually cause it to fail. Early symptoms manifest as having to heat the plug to higher and higher temperatures to maintain the H2 flow. How about reversing the differential pressure to backflush it, every decade or so? When the hydrogen bottle is changed you must perform a purge routine (see the manual) to allow any foreign gases to be removed. Of course. So for maximum life the Hydrogen should be as pure as possible. The resonator coil cannot be seen, I can see that it is a bit different than the manual shows. It was upgraded at some point. I can provide a picture of another masers coil. The manual showed a helix surrounding the bulb. It ocurred to me that it might be acting as a resonant antenna, rather than just a distributed electrode. The receiving tank did not heat up all. Since I was going from a higher pressure tank to a mostly empty tank I don't think compression was involved The gas pressure in the small tank was increasing, hence it's being compressed in the smaller tank. I know Lecture Bottles get warm while filling to 2000 psi. Best, -John = ___ 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] WeirdStuff tbolt $75
Ah, yes. Express courier service is always spendy. -Pete On 09/02/2010 10:09 AM, K. Szeker wrote: Hi Peter, You are right, in the text/details are, for same destination, more moderate prices too Under the cover shipments costs was the expensivste to see... US $105,35 Deutschland UPS Worldwide ExpressSM US $96,97 Deutschland UPS Worldwide ExpeditedSM US $31,05 Deutschland USPS Priority Mail InternationalTM Greetings! Karesz 2010/9/2 Peter Loronpet...@standingwave.org: Umm, their eBay listing shows like $11 for US domestic shipping and $30 to Turkmenistan...seems pretty in line with reality... -Pete On 09/02/2010 09:49 AM, K. Szeker wrote: And we should not forget the extra expensive Shipping: $105.35 UPS Worldwide Express too... K. 2010/9/2 Leigh L. Klotz, Jr WA5ZNUle...@wa5znu.org: WeirdStuff has tbolts, no case, no info about firmware version, for $75. They were $495 but I sent them a note saying it wasn't a competitive price and they lowered it and they appear to be selling out quickly. http://www.weirdstuff.com/cgi-bin/category.cgi?item=29654 Also on their weirdstuff-inc ebay store for the so inclined. Leigh/WA5ZNU ___ ___ 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] Choice of MASER gas
FYI, Ron Walsworth did his PhD in Prof. Ike Silvera's Group at Harvard. Among his advisors were Robert Vesseau of SAO/CFA, the builder of a number of very high performance H2 MASERS. Ron's experiment was trying to build an H2 MASER with superfluid He coated walls. Best, -John John Miles brought up an interesting question that got lost in the discussion of high vacuum systems: what about the choice of gas? Besides H, there is a dual Xe/He system detailed in: http://www.cfa.harvard.edu/Walsworth/pdf/Bear%20thesis.pdf And, as mentioned before, Harvard has built Rb masers: http://cfa-www.harvard.edu/~dphil/work/coat.pdfhttp://cfa-www.harvard.edu/%7Edphil/work/coat.pdf http://cfa-www.harvard.edu/%7Edphil/work/coat.pdf And John mentioned HN3 masers (advantage: you would be able to smell the leak!). ___ 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] Maser info (vacuum levels)
Back to the Palladium plug for a minute. The problem you mentioned about the valve not shutting off completely is analogous to the problem with HeCd LASERs. In a HeCd LASER, there is an oven with Cd metal in it that is heated to provide Cd ions to the discharge tube. There is also He in the tube. The balance between the partial pressures of He and Cd needs to be within fairly close tolerances to sustain suffcient population inversion for the thing to lase. Well, the electric field causes Cd to migrate to the negative end of the tube and go splat against the cathode, entrapping He atoms, just like a sputter pump. This depletes the He in the tube and it stops working, so they add a He reservoir with a heated glass diaphragm as a valve to replenish the He in the discharge tube. Problem is, the diaphragm leaks He, even when the thing is shut off at room temperature. And, it uses up Cd to sputter pump He when you turn it back on. Adjusting one of these beasts is non-trivial. You have to get the He/Cd mix right (by looking at the strength of spectral lines) then adjust the mirrors at both ends of the resonator. It takes a while. :)) Best, -John This EFOS maser typically runs with the two vacuum pressures below 1.5 X 10-6 Torr. (as measured via the ion pump current) Maximum should not exceed about 3.6 X 10-6 Torr for either pump. The internal vacuum will drop to about 1 X10-7 Torr if the Hydrogen to the disassociator is turned off. One pump pumps the internal which is the maser bulb, the disassociator, and the connecting lines, so mainly just pumps Hydrogen. (fairly low volume) The external pump pumps the insulating outer shell and the interior of the maser cavity. It pumps any leakage or outgassing that occurs. (much larger volume) Pumps are 20 LPS varian triodes. Corby Dawson Moms Asked to Return to School Grant Funding May Be Available to Those That Qualify. http://thirdpartyoffers.juno.com/TGL3141/4c7fdedb5d30e0abfm04duc ___ 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] Maser info (vacuum levels)
On Sep 2, 2010, at 10:28 AM, Corby Dawson wrote: This EFOS maser typically runs with the two vacuum pressures below 1.5 X 10-6 Torr. (as measured via the ion pump current) Maximum should not exceed about 3.6 X 10-6 Torr for either pump. The internal vacuum will drop to about 1 X10-7 Torr if the Hydrogen to the disassociator is turned off. Back in college, I took a semiconductor device physics course which included a lab where we made simple ICs (the most complex devices were SR latches). We had a vapor deposition system for plating on gold or aluminum, which pumped the chamber down below 10E-12 Torr as I recall, within ten minutes or so after a clueless freshman opened the beast up and tossed in a bit of aluminum or gold wire and a few chunks of silicon with their grubby hands (ok, we used tweezers, but still...). The whole unit was about as big as a refrigerator or two. It used a rotary-vane roughing pump and an oil diffusion pump with a liquid nitrogen trap. This was about 25 years ago. Reading here about the troubles of pulling a very good vacuum, I'm now wondering what sorts of painful engineering went into making the machine turn-key and freshman-proof? It's entirely possible that I've mis-remembered the pressure level, but that's the exponent that stuck in my mind for whatever reason. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] WeirdStuff tbolt $75 [eBay Link]
On Sep 2, 2010, at 10:06 AM, Oz-in-DFW wrote: http://cgi.ebay.com/300457580821 And still more than 10 available. That listing appears to have ended. If I had gotten there in time, I'd have been tempted to buy a couple of them. My Thunderbolt is flaky (stops outputting serial data or responding to serial commands after a period of minutes to hours), so I could have tried out a couple others in hopes of finding a reliable one, followed by harvesting OCXOs from the ones that didn't make the cut. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Maser info (vacuum levels)
Two things helped a lot: Big pumps and an LN2 cold trap. The LN2 trap (as long as it is kept filled) will condense most everything except a few permanent gases. It also stops the backflow of pump oil. However, if something goes wrong, you would not believe the mess. A technician that worked for me years ago told of a vacuum chamber that was used to test some Apollo instruments, maybe 6' long and 5' diameter with a pair of 18 - 24 oil diff pumps. One night the AC power went off and the emergency sequence failed. The diff pump oil was sucked back into the system. It took them weeks to take the whole thing appart, clean everything (think 55 gallon drums of Trichlor) and get it back together. No thanks, -John == On Sep 2, 2010, at 10:28 AM, Corby Dawson wrote: This EFOS maser typically runs with the two vacuum pressures below 1.5 X 10-6 Torr. (as measured via the ion pump current) Maximum should not exceed about 3.6 X 10-6 Torr for either pump. The internal vacuum will drop to about 1 X10-7 Torr if the Hydrogen to the disassociator is turned off. Back in college, I took a semiconductor device physics course which included a lab where we made simple ICs (the most complex devices were SR latches). We had a vapor deposition system for plating on gold or aluminum, which pumped the chamber down below 10E-12 Torr as I recall, within ten minutes or so after a clueless freshman opened the beast up and tossed in a bit of aluminum or gold wire and a few chunks of silicon with their grubby hands (ok, we used tweezers, but still...). The whole unit was about as big as a refrigerator or two. It used a rotary-vane roughing pump and an oil diffusion pump with a liquid nitrogen trap. This was about 25 years ago. Reading here about the troubles of pulling a very good vacuum, I'm now wondering what sorts of painful engineering went into making the machine turn-key and freshman-proof? It's entirely possible that I've mis-remembered the pressure level, but that's the exponent that stuck in my mind for whatever reason. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] WeirdStuff tbolt $75 [eBay Link]
There are several packaged versions up for $100 and modest shipping. On 9/2/2010 1:29 PM, Oz-in-DFW wrote: I'm guessing they had 18 and someone bought the last. On 9/2/2010 1:25 PM, Mark J. Blair wrote: On Sep 2, 2010, at 10:06 AM, Oz-in-DFW wrote: http://cgi.ebay.com/300457580821 And still more than 10 available. That listing appears to have ended. If I had gotten there in time, I'd have been tempted to buy a couple of them. My Thunderbolt is flaky (stops outputting serial data or responding to serial commands after a period of minutes to hours), so I could have tried out a couple others in hopes of finding a reliable one, followed by harvesting OCXOs from the ones that didn't make the cut. -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ 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] WeirdStuff tbolt $75 [eBay Link]
Sorry, sorgot to include link; http://cgi.ebay.com/330453047354 also more than 10 available. On 9/2/2010 1:31 PM, Oz-in-DFW wrote: There are several packaged versions up for $100 and modest shipping. On 9/2/2010 1:29 PM, Oz-in-DFW wrote: I'm guessing they had 18 and someone bought the last. On 9/2/2010 1:25 PM, Mark J. Blair wrote: On Sep 2, 2010, at 10:06 AM, Oz-in-DFW wrote: http://cgi.ebay.com/300457580821 And still more than 10 available. That listing appears to have ended. If I had gotten there in time, I'd have been tempted to buy a couple of them. My Thunderbolt is flaky (stops outputting serial data or responding to serial commands after a period of minutes to hours), so I could have tried out a couple others in hopes of finding a reliable one, followed by harvesting OCXOs from the ones that didn't make the cut. -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ 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] Maser info (rough pumping)
With the triode pumps you only need the vacsorbs for roughing, as they will start at a higher pressure! I have changed two ion pumps so far and only used the vacsorbs to get back in operation. The vacsorbs and accessories were eBay buys over a period of a few months and very reasonable compared to a turbo pump! As far as the hydrogen supply I had considered replacing the bottle with a hydride storage unit. There were several different units I looked at a year or so ago and they were fairly reasonable and compact. If I had to homebrew a hydrogen leak I would use thin wall nickel tubing instead of the palladium plug. There are details in some of the maser stuff on-line about its construction. Corby Dawson Refinance Now 3.7% FIXED $160,000 Mortgage: $547/mo. No Hidden Fees. No SSN Req. Get 4 Quotes! http://thirdpartyoffers.juno.com/TGL3141/4c7ff358e41ebe0ea3m04duc ___ 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] Maser info (vacuum levels)
At 01:17 PM 9/2/2010, Mark J. Blair wrote: Back in college, I took a semiconductor device physics course which included a lab where we made simple ICs (the most complex devices were SR latches). We had a vapor deposition system for plating on gold or aluminum, which pumped the chamber down below 10E-12 Torr as I recall, within ten minutes or so after a clueless freshman opened the beast up and tossed in a bit of aluminum or gold wire and a few chunks of silicon with their grubby hands (ok, we used tweezers, but still...). The whole unit was about as big as a refrigerator or two. It used a rotary-vane roughing pump and an oil diffusion pump with a liquid nitrogen trap. This was about 25 years ago. I think I took that same class (sub-basement of Steele, right?) just a few years after you. -- newell N5TNL ___ 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] Maser (oil diffusion rough pumps)
John F. Google Maser contamination and you will find a Russian blurb describing what I'm talking about. Even with LN2 traps they had problems. Corby Dawson $350,000 Life Insurance Coverage as low as $13.04/month. Free, No Obligation Quotes. http://thirdpartyoffers.juno.com/TGL3141/4c7ff7df46a9ee0fabm04duc ___ 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] Maser info (vacuum levels)
On Sep 2, 2010, at 12:00 PM, Scott Newell wrote: I think I took that same class (sub-basement of Steele, right?) just a few years after you. That would be the one! See, I knew that most anybody who attended that particular institution would recognize my description of that piece of equipment. I took the classes in '86-'87. I would have been class of '90 if I hadn't flunked three quarters of math and two quarters of physics... but the lure of the device physics lab was enough incentive for me to bludgeon my brain into passing that pair of device physics courses. I also thoroughly kicked butt in the freshman-level digital electronics courses, which oddly enough were easily as advanced as the junior-level digital electronics courses that I eventually took at UC Irvine. A big portion of my career naturally has involved digital ASIC design, since that and software development appear to be the things that I can idiot-savant my way through while only understanding enough math to be able to count to 1! :-) What house were you in? I was in the red one, with a guest membership in the black one due to my disrespect of security devices and interest in telephone switching networks. Have you ever followed the yellow brick road to cold under Arms? -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Maser/Interociter
Bill, Here's a PIX if it does not get scrubbed off! Corby Mortgage Rates Hit 3.25% If you owe under $729k you probably qualify for Obama's Refi Program http://thirdpartyoffers.juno.com/TGL3141/4c7ffbafe538be103am04ducinterociter3.jpg___ 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] Maser (oil diffusion rough pumps)
Hi Corby, I don't doubt it for an instant. Oil pumps just don't hack it for UHV. If you are going to use oil pumps for almost anything serious you must use an LN2 trap. In a He Leak Detector, for example, an oil system is often used. BTW, Varian specifically say not to use Silicone oils as they permanently destroy the mass specs. Do you have an RGA on your MASER? Best, -John === John F. Google Maser contamination and you will find a Russian blurb describing what I'm talking about. Even with LN2 traps they had problems. Corby Dawson $350,000 Life Insurance Coverage as low as $13.04/month. Free, No Obligation Quotes. http://thirdpartyoffers.juno.com/TGL3141/4c7ff7df46a9ee0fabm04duc ___ 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] Maser (RGA)
John F. I don't have an RGA as there are no leaks to speak of in the Maser. I do have an annoying leak in my roughing manifold but plan to pump it down and spray some helium around the suspect area and see if my millitorr gauge will respond. It's a tiny leak as I can do a pumpdown OK but I'd like to eliminate it! Only need to rough when changing pumps an thats's not even a yearly event. Corby Compare Life Ins Rates Protect Your Family Today for under $1/day. Quotes from top providers http://thirdpartyoffers.juno.com/TGL3141/4c7ffe8b5aa42e10e4m04duc ___ 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] Maser/Interociter
we come from a different planet we mean no harm On Thu, Sep 2, 2010 at 3:31 PM, Corby Dawson cdel...@juno.com wrote: Bill, Here's a PIX if it does not get scrubbed off! Corby Mortgage Rates Hit 3.25% If you owe under $729k you probably qualify for Obama's Refi Program http://thirdpartyoffers.juno.com/TGL3141/4c7ffbafe538be103am04duc ___ 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] Maser (RGA)
John F. I don't have an RGA as there are no leaks to speak of in the Maser. Well, that's good! I do have an annoying leak in my roughing manifold but plan to pump it down and spray some helium around the suspect area and see if my millitorr gauge will respond. The choice of stuff to spray may depend on the type of guage you have. It's a tiny leak as I can do a pumpdown OK but I'd like to eliminate it! Understood. Only need to rough when changing pumps an thats's not even a yearly event. Corby If the MASER is tight, the pumps should last a long time. Thanks, -John == ___ 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] WeirdStuff tbolt $75
Leigh, What was your search term? The link does not produce anything. Bob - Original Message - From: Leigh L. Klotz, Jr WA5ZNU le...@wa5znu.org To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 02, 2010 12:06 PM Subject: [time-nuts] WeirdStuff tbolt $75 WeirdStuff has tbolts, no case, no info about firmware version, for $75. They were $495 but I sent them a note saying it wasn't a competitive price and they lowered it and they appear to be selling out quickly. http://www.weirdstuff.com/cgi-bin/category.cgi?item=29654 Also on their weirdstuff-inc ebay store for the so inclined. Leigh/WA5ZNU ___ 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] Maser (pump life)
John F. The internal pump lifetime is reduced as it has to pump the waste Hydrogen after it leaves the bulb. These pumps elements swell after burying increasing amounts of Hydrogen and eventually short out. Corby Dawson Mortgage Rates Hit 3.25% If you owe under $729k you probably qualify for Obama's Refi Program http://thirdpartyoffers.juno.com/TGL3141/4c8004fb17de9e120fm04duc ___ 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] WeirdStuff tbolt $75
Hi Bob, it was only shortfor time on the WeirdStuff-side on, after that on the firms shop/eBay side was the spoken situation, but yet its finished too... :-( http://cgi.ebay.ch/ws/eBayISAPI.dll?ViewItemitem=300457580821ssPageName=STRK:MEWAX:IT Karesz 2010/9/2 Robert Benward rbenw...@verizon.net: Leigh, What was your search term? The link does not produce anything. Bob - Original Message - From: Leigh L. Klotz, Jr WA5ZNU le...@wa5znu.org To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, September 02, 2010 12:06 PM Subject: [time-nuts] WeirdStuff tbolt $75 WeirdStuff has tbolts, no case, no info about firmware version, for $75. They were $495 but I sent them a note saying it wasn't a competitive price and they lowered it and they appear to be selling out quickly. http://www.weirdstuff.com/cgi-bin/category.cgi?item=29654 Also on their weirdstuff-inc ebay store for the so inclined. Leigh/WA5ZNU ___ 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] Maser (pump life)
John F. The internal pump lifetime is reduced as it has to pump the waste Hydrogen after it leaves the bulb. OK. Understood. These pumps elements swell after burying increasing amounts of Hydrogen and eventually short out. Some pumps have replacable elements. Do these? Or do you have to swap the whole thing out? There was a company that rebuilt some types, but I've forgotten who. -John Corby Dawson ___ 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] Maser (pump rebuild)
John F. The pumps can be rebuilt. Duniway Stockroom here in CA. among others does the deed. Corby Moms Asked to Return to School Grant Funding May Be Available to Those That Qualify. http://thirdpartyoffers.juno.com/TGL3141/4c800a3d11a68e1359m04duc ___ 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] Maser (pump rebuild)
Hi Corby, Thanks. Duniway was the company, but it slipped my mind. They have about the best prices on Conflat stuff going, I think, outside of eBay. Best, -John == John F. The pumps can be rebuilt. Duniway Stockroom here in CA. among others does the deed. Corby ___ 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] Small DMTD project PCBs Group Buy Update
In a message dated 02/09/2010 01:58:00 GMT Daylight Time, stanley_reyno...@yahoo.com writes: Boards will be here Friday September 3. --- Hi Stanley Many thanks for the update, I'd like 4 Mixer PCBs please and 2 DDS PCBs and have just made payment for these via Paypal. regards Nigel GM8PZR ___ 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] Freestanding mast
I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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] Looking for High Q ceramic cylinders
Hello, I'm looking for manufactors/distributors of High Q (high Epsilon r) ceramic materials. Best would be cylindrical forms of ~ 10-30mm diameter. Has anybody informations where to buy? Thanks in advance Peter, DG4EK ___ 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] Freestanding mast
It may not be a problem where you are, but I should think that lightning might come to mind. Do you really want your GPS antenna up very high? -Chuck Harris Charles P. Steinmetz wrote: I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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] Freestanding mast
ROHN 9H50 34 Foot Telescopic TV Wireless Antenna Push Up Mast http://www.3starinc.com/rohn_telescopic_masts.html I don't know this vendor just the first that came up in google. Stanley - Original Message From: Charles P. Steinmetz charles_steinm...@lavabit.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 2, 2010 7:46:00 PM Subject: [time-nuts] Freestanding mast I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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] Freestanding mast
On 9/2/2010 7:46 PM, Charles P. Steinmetz wrote: I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. How far up do you need to go? Do you need to clear dense trees or lots of adjacent buildings, and if so, how high are they? If you get about all nearby structure and obstructions you need to start thinking about lightning protection in a vary serious way. Should be able to survive at least Category 2 winds and heavy snow and ice. The definition of heavy snow and ice is very regionally dependent. I'm in the DFW are and heavy = any. I used to live in Laramie and worked on mountaintop radios where heavy was measured in feet. Where are you? Likewise the structure required to support survivability is heavily dependent on worst case ice load and height. 110 mph/50 m/s isn't that hard for a few feet of pipe clamped securely to a structure to survive. Even ice load isn't much of a factor as it's more structural than load for a small antenna and short pipe at some point . Falling ice clears all bets. Literally. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Most of the telecom targeted antennas are made to screw on to 3/4 or 1 water pipe with the feedline in the pipe. Typical application is either: 1. A short (1 - 2 foot) piece of rigid conduit of the correct size is fit to the shelter with a sweep bend to feed the antenna feedline directly into the building. These are often not clamped at all, though frequently clamped to an eave. 2. A short (1 - 3 foot) piece is clamped to a larger mast and a longer feedline is run into the building. Thanks, Charles I suspect you may be over thinking this and a foot or two of pipe on an appropriately located eave will do fine. If you need to go on a chimney, get a chimney strap kit and four feet of pipe sized to fit the antenna. Strap it at points two or three feet apart. -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ 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] Freestanding mast
I was just about to suggest a ham antenna tower. The triangular truss design is very rigid, yet presents low wind loading. I think there are application notes that help with siting and selection. Rohn is a very standard and pretty well respected name in the business. They also have a good selection of accessories. In this area, I see them at ham fleas on a regular basis. FWIW, -John === ROHN 9H50 34 Foot Telescopic TV Wireless Antenna Push Up Mast http://www.3starinc.com/rohn_telescopic_masts.html I don't know this vendor just the first that came up in google. Stanley - Original Message From: Charles P. Steinmetz charles_steinm...@lavabit.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 2, 2010 7:46:00 PM Subject: [time-nuts] Freestanding mast I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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 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] Freestanding mast
Hi There are a lot of chimney mount antenna supports. They should get you up 6 feet above the top of the chimney. Simple to install and pretty cheap. Bob On Sep 2, 2010, at 8:46 PM, Charles P. Steinmetz charles_steinm...@lavabit.com wrote: I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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] Freestanding mast
Picked that one as it fit the 3 wide request and is UPS shippable. The brackets and ground plate were also available. Stanley - Original Message From: J. Forster j...@quik.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 2, 2010 8:25:35 PM Subject: Re: [time-nuts] Freestanding mast I was just about to suggest a ham antenna tower. The triangular truss design is very rigid, yet presents low wind loading. I think there are application notes that help with siting and selection. Rohn is a very standard and pretty well respected name in the business. They also have a good selection of accessories. In this area, I see them at ham fleas on a regular basis. FWIW, -John === ROHN 9H50 34 Foot Telescopic TV Wireless Antenna Push Up Mast http://www.3starinc.com/rohn_telescopic_masts.html I don't know this vendor just the first that came up in google. Stanley - Original Message From: Charles P. Steinmetz charles_steinm...@lavabit.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 2, 2010 7:46:00 PM Subject: [time-nuts] Freestanding mast I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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 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] Freestanding mast
Hello Charles, Last September I had some roof work done and I had added 2 each 1-1/2 vent pipe penetrations just below the ridge. Now I have a place to add the GPS antenna, either a hockey puck type or a more sophisticated one. The hockey puck was added to a length of PVC conduit to penetrate the gland The GPS antenna is just level with the roof ridge, for no blockage. Previously I used a MS-44 aluminum military masting tripod tower to put the GPS antenna just above the gutter height ~ 11' high. The rest of your questions I would have to find a PE. Stan, W1LE On 9/2/2010 8:46 PM, Charles P. Steinmetz wrote: I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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] Freestanding mast
Make sure you are sitting down when you check the shipping charges. 73, Dick, W1KSZ -Original Message- From: Stanley Reynolds stanley_reyno...@yahoo.com Sent: Sep 2, 2010 9:16 PM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Freestanding mast ROHN 9H50 34 Foot Telescopic TV Wireless Antenna Push Up Mast http://www.3starinc.com/rohn_telescopic_masts.html I don't know this vendor just the first that came up in google. Stanley - Original Message From: Charles P. Steinmetz charles_steinm...@lavabit.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 2, 2010 7:46:00 PM Subject: [time-nuts] Freestanding mast I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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 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] Freestanding mast
$32.61 for me but maybe you are further away, heavy stuff, maybe it would pay to shop for a closer vendor. Stanley - Original Message From: Richard W. Solomon w1...@earthlink.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 2, 2010 8:49:24 PM Subject: Re: [time-nuts] Freestanding mast Make sure you are sitting down when you check the shipping charges. 73, Dick, W1KSZ -Original Message- From: Stanley Reynolds stanley_reyno...@yahoo.com Sent: Sep 2, 2010 9:16 PM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Freestanding mast ROHN 9H50 34 Foot Telescopic TV Wireless Antenna Push Up Mast http://www.3starinc.com/rohn_telescopic_masts.html I don't know this vendor just the first that came up in google. Stanley - Original Message From: Charles P. Steinmetz charles_steinm...@lavabit.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 2, 2010 7:46:00 PM Subject: [time-nuts] Freestanding mast I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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 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] Freestanding mast
I've a Symmetricom(HP) 58532A antenna on a six foot mast -- T6061 aluminum schedule 40 pipe. Not as cheap as cast schedule 40 from the home store, but a lot lighter! The previous mast was a length of cheezy Radio Shack antenna mast -- thin wall stuff. The mount for the 58532A wanted larger diameter schedule 40. Oh, that mast also supports a Davis Instruments Vantage Pro2 weather package -- the GPS antenna is on the mast, which is between the rain collector bucket and the anemometer mast. The rain bucket is due south of the GPS antenna, and below the GPS antenna horizon. While the anemometer mast holds the anemometer assembly up a few inches, it's due north, so it's in the region where the GPS birds don't go anyway, and is below the elevation mask angle as well as the angle at which the birds appear. Life is full of compromises... We get very little snow and/or ice here, but usually have storms in the winter with 50+ MPH winds. A 10 foot stick of the cheezy thin wall held up the weather instruments for a number of seasons with no problems. The 58532A doesn't add appreciable cross section in comparison to the rain bucket. I don't anticipate problems with the larger diameter mast, and would expect a 10 foot length to be quite stable. T6061 aluminum is a favourite for antenna construction. (I went with the six foot length as it was available as scrap.) Separate 24 hour antenna surveys with the weather sensors six inches or so below the GPS antenna, and then with the weather sensors at their nominal operating height with respect to the GPS antenna did not show easily observable differences in tbolt operation. 73 de Bob K6RTM in Silicon Valley -- Message: 2 Date: Thu, 02 Sep 2010 20:46:00 -0400 From: Charles P. Steinmetz charles_steinm...@lavabit.com Subject: [time-nuts] Freestanding mast To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 20100903004603.b222311b...@karen.lavabit.com Content-Type: text/plain; charset=us-ascii; format=flowed I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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] Freestanding mast
If your nearby houses and obstructions are not high, IE. if the houses there are single story, you may be able to get away with what I have done. Instead of fixing something on the house, I've attached a couple of antenna to the top of one of my washing line poles in the garden as this faces South (I'm in the Southern Hemisphere) and I get an average of 7-8 sats every day and up to 12 at night. It makes any maintenance easy, if you get any snow it is easy to clear at that height, there is much less windage if your subject to strong winds and, if you don't use your washing line, the size of the poles make them quite rigid so you don't suffer a lot of noise that you would high up on a thin pole. Just a thought. Steve On 3 September 2010 12:46, Charles P. Steinmetz charles_steinm...@lavabit.com wrote: I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ 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] Freestanding mast
Bob, Don't get me started on my Davis Instruments Vantage Pro 2 with BIRDS... and the rain bucket! ;) How many times have you cleaned yours out this year? Spiders and Wasps are the worst. But... unfortunately, my flag pole is now the weather station mount (wireless version) and it's too far away to mount my multiple GPS antennas. I run both Weather Display and VWS (and a LOT of other software for the weather station)... what are you running? Do you know of anyway to sync the timestamps of the weather station to a Thunderbolt? 73 Brice KA8MAV - Original Message - From: k6...@comcast.net To: time-nuts@febo.com Sent: Thursday, September 02, 2010 11:27 PM Subject: Re: [time-nuts] Freestanding mast I've a Symmetricom(HP) 58532A antenna on a six foot mast -- T6061 aluminum schedule 40 pipe. Not as cheap as cast schedule 40 from the home store, but a lot lighter! The previous mast was a length of cheezy Radio Shack antenna mast -- thin wall stuff. The mount for the 58532A wanted larger diameter schedule 40. Oh, that mast also supports a Davis Instruments Vantage Pro2 weather package -- the GPS antenna is on the mast, which is between the rain collector bucket and the anemometer mast. The rain bucket is due south of the GPS antenna, and below the GPS antenna horizon. While the anemometer mast holds the anemometer assembly up a few inches, it's due north, so it's in the region where the GPS birds don't go anyway, and is below the elevation mask angle as well as the angle at which the birds appear. Life is full of compromises... We get very little snow and/or ice here, but usually have storms in the winter with 50+ MPH winds. A 10 foot stick of the cheezy thin wall held up the weather instruments for a number of seasons with no problems. The 58532A doesn't add appreciable cross section in comparison to the rain bucket. I don't anticipate problems with the larger diameter mast, and would expect a 10 foot length to be quite stable. T6061 aluminum is a favourite for antenna construction. (I went with the six foot length as it was available as scrap.) Separate 24 hour antenna surveys with the weather sensors six inches or so below the GPS antenna, and then with the weather sensors at their nominal operating height with respect to the GPS antenna did not show easily observable differences in tbolt operation. 73 de Bob K6RTM in Silicon Valley -- Message: 2 Date: Thu, 02 Sep 2010 20:46:00 -0400 From: Charles P. Steinmetz charles_steinm...@lavabit.com Subject: [time-nuts] Freestanding mast To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 20100903004603.b222311b...@karen.lavabit.com Content-Type: text/plain; charset=us-ascii; format=flowed I'm curious what the best freestanding mast is for a timing antenna (think Lucent timing antenna or marine mushroom GPS antenna -- light and pretty small). The mast would have its highest support at rooftop or chimney-top level, and could extend from there as far downward as the ground with additional supports as required. Should be able to survive at least Category 2 winds and heavy snow and ice. What reasonably available mast material no more than, say, 3 in maximum cross-section would allow the most vertical extension above the highest support, and how much extension would that be? I'm thinking 10 feet of 2 or so thin-wall steel tube may be OK, but beyond that I don't know. Tubing is probably not the optimum shape, but I assume the availability of other engineering shapes (say, + cross-section) is likely to be limited. Ideas? Thanks, Charles ___ 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] Maser info (vacuum levels)
Mark J. Blair wrote: On Sep 2, 2010, at 10:28 AM, Corby Dawson wrote: This EFOS maser typically runs with the two vacuum pressures below 1.5 X 10-6 Torr. (as measured via the ion pump current) Maximum should not exceed about 3.6 X 10-6 Torr for either pump. The internal vacuum will drop to about 1 X10-7 Torr if the Hydrogen to the disassociator is turned off. Back in college, I took a semiconductor device physics course which included a lab where we made simple ICs (the most complex devices were SR latches). We had a vapor deposition system for plating on gold or aluminum, which pumped the chamber down below 10E-12 Torr maybe 1E-6 micron (1E-9 torr).. as I recall, within ten minutes or so after a clueless freshman opened the beast up and tossed in a bit of aluminum or gold wire and a few chunks of silicon with their grubby hands (ok, we used tweezers, but still...). The whole unit was about as big as a refrigerator or two. It used a rotary-vane roughing pump and an oil diffusion pump with a liquid nitrogen trap. This was about 25 years ago. Sounds about right.. the mechanical pump will pull it down to a few microns in a minute or so (I assume it's like a bell jar with maybe 50 liters total volume?) Another 10 minues on the diff pump (probably something like a 4 throat.. with a LN2 trap).. As long as you don't forget to close the High vacuum gate valve before venting the chamber, very reasonable. Reading here about the troubles of pulling a very good vacuum, I'm now wondering what sorts of painful engineering went into making the machine turn-key and freshman-proof? It's entirely possible that I've mis-remembered the pressure level, but that's the exponent that stuck in my mind for whatever reason. Lots of interlocks to keep you from doing dumb stuff (e.g. venting to atmosphere with the diff pump hot and connected), actually not all that dirty.. you probably weren't sticking complex mechanical stuff in there.. basically a wafer that you'd put next to the evaporator source. So no issues with virtual leaks, etc. At work, we've got tons (well, tens) of these little evaporation workstation things.. A rolling cart about a meter by half a meter, and a meter high, with a bell jar on top. A mechanical two stage pump and a 3 diff pump under the plate. A couple of feedthroughs for current to heat the evaporation source. A couple toggle switches, a ion and a thermocouple gage.. We don't use the for evaporating metal (at least I and the folks in my section don't)... we use them to test electronics under vacuum.. ___ 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] Maser info (vacuum levels)
Sounds like the parts of a salvaged SEM would be a good start for a project such as this (assuming the diffusion pump is included - I've been looking for one for a while but it seems the pumps are almost *always* missing). But still, if you could find one locally (freight is $$$) there are a lot of very good, high precision parts just begging to be hacked. - Original Message - From: jimlux jim...@earthlink.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Friday, September 03, 2010 12:34 AM Subject: Re: [time-nuts] Maser info (vacuum levels) Mark J. Blair wrote: On Sep 2, 2010, at 10:28 AM, Corby Dawson wrote: This EFOS maser typically runs with the two vacuum pressures below 1.5 X 10-6 Torr. (as measured via the ion pump current) Maximum should not exceed about 3.6 X 10-6 Torr for either pump. The internal vacuum will drop to about 1 X10-7 Torr if the Hydrogen to the disassociator is turned off. Back in college, I took a semiconductor device physics course which included a lab where we made simple ICs (the most complex devices were SR latches). We had a vapor deposition system for plating on gold or aluminum, which pumped the chamber down below 10E-12 Torr maybe 1E-6 micron (1E-9 torr).. as I recall, within ten minutes or so after a clueless freshman opened the beast up and tossed in a bit of aluminum or gold wire and a few chunks of silicon with their grubby hands (ok, we used tweezers, but still...). The whole unit was about as big as a refrigerator or two. It used a rotary-vane roughing pump and an oil diffusion pump with a liquid nitrogen trap. This was about 25 years ago. Sounds about right.. the mechanical pump will pull it down to a few microns in a minute or so (I assume it's like a bell jar with maybe 50 liters total volume?) Another 10 minues on the diff pump (probably something like a 4 throat.. with a LN2 trap).. As long as you don't forget to close the High vacuum gate valve before venting the chamber, very reasonable. Reading here about the troubles of pulling a very good vacuum, I'm now wondering what sorts of painful engineering went into making the machine turn-key and freshman-proof? It's entirely possible that I've mis-remembered the pressure level, but that's the exponent that stuck in my mind for whatever reason. Lots of interlocks to keep you from doing dumb stuff (e.g. venting to atmosphere with the diff pump hot and connected), actually not all that dirty.. you probably weren't sticking complex mechanical stuff in there.. basically a wafer that you'd put next to the evaporator source. So no issues with virtual leaks, etc. At work, we've got tons (well, tens) of these little evaporation workstation things.. A rolling cart about a meter by half a meter, and a meter high, with a bell jar on top. A mechanical two stage pump and a 3 diff pump under the plate. A couple of feedthroughs for current to heat the evaporation source. A couple toggle switches, a ion and a thermocouple gage.. We don't use the for evaporating metal (at least I and the folks in my section don't)... we use them to test electronics under vacuum.. ___ 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] Maser (pump rebuild)
Corby Dawson wrote: John F. The pumps can be rebuilt. Duniway Stockroom here in CA. among others does the deed. Duniway is great for odds and ends on vacuum gear in general. Sure, you can buy stuff surplus, but you always wind up needing some funky plumbing, or a seal kit, or some rebuild widget. A former employer was addicted to auction sales.. we had a whole room full of fab equipment bought at auction.. (and a NMR setup with a giant water cooled electromagnet.. 100Amps at 100Volts regulated to microamps.. Got some of it working, but never did see a an actual resonance) ___ 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] Maser info (vacuum levels)
Surplus (free to good home table)? Try finding someone who works with these pumps every day who will even part with an OLD pump (even if it doesn't work) just because... a broken spare is better than not having anything at all. ;) - Original Message - From: jimlux jim...@earthlink.net To: j...@quik.com; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Friday, September 03, 2010 12:45 AM Subject: Re: [time-nuts] Maser info (vacuum levels) J. Forster wrote: Two things helped a lot: Big pumps and an LN2 cold trap. The LN2 trap (as long as it is kept filled) will condense most everything except a few permanent gases. It also stops the backflow of pump oil. However, if something goes wrong, you would not believe the mess. A technician that worked for me years ago told of a vacuum chamber that was used to test some Apollo instruments, maybe 6' long and 5' diameter with a pair of 18 - 24 oil diff pumps. Yep, that sounds pretty typical for our thermal vacuum test setups.. (JPL has some bigger chambers.. 25 foot with a solar simulator, for instance). The one I like is the RF test chamber.. a 6 foot bell jar in an anechoic chamber for testing antennas under high power.. I think that one has a 3 foot diameter aperture to the pump (52,000 liters/second.. yes indeed that is a *fast* pump). http://mesa.jpl.nasa.gov/Vacuum_Breakdown_Facility/ Actually, it's kind of interesting at the lab because there's all this old stuff not being used anymore (giant roots roughing pumps), but it's still connected up to the walls, even if the insides of the lab has had the chamber removed. It's probably more expensive to remove the pumps and dispose of them as surplus than it is to just leave them in place (where they've probably been since the 60s). I do know that getting rid of an old small pump is a huge pain.. someone has to come and certify it as not being hazardous, and then they take it to some disposal facility, and then it has to be listed for recovery, and some scrap dealer bids on it (probably as a lot weighing a ton or more) (e.g. no dumpster diving for employees..) One night the AC power went off and the emergency sequence failed. The diff pump oil was sucked back into the system. It took them weeks to take the whole thing appart, clean everything (think 55 gallon drums of Trichlor) and get it back together. Oh yes... venting the chamber when the pump is hot is a BIG no-no.. Even moreso when there's hardware under test in the chamber. (we had a piece of gear going through thermal vac with a cold plate using a glycol loop to the chiller.. and the glycol leaked..) ___ 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] Looking for High Q ceramic cylinders
Peter Krengel wrote: Hello, I'm looking for manufactors/distributors of High Q (high Epsilon r) ceramic materials. Best would be cylindrical forms of ~ 10-30mm diameter. Mfrs... Epson Coors Murata Erie TDK All have reps world wide google alumina substrate That will get you started with mfrs.. then the web site will tell you what other shapes they have. Has anybody informations where to buy? ___ 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] Maser info (vacuum levels)
Heathkid wrote: Sounds like the parts of a salvaged SEM would be a good start for a project such as this (assuming the diffusion pump is included - I've been looking for one for a while but it seems the pumps are almost *always* missing). But still, if you could find one locally (freight is $$$) there are a lot of very good, high precision parts just begging to be hacked. I haven't checked recently, but used/rebuilt diff pumps used to be really, really cheap (because everyone using them in a process situation was going to turbos, etc.). Sure, you might wind up buying a whole pallet load of them, and half would be gunked up with some weird toxic carbonized slime, but those you just pitch. Some of the others would have a heater that's broken, but you cannibalize off another one. They have the virtue of simplicity.. I've always thought that it might not be that hard to hack a turbo pump.. I used to see the pump heads are readily available for cheap, it's the 3 phase inverter/motor drive that's expensive, but with modern VFDs maybe something could be hacked. (yes, it's a different set of problems than a diff pump.. choose your poison?) ___ 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] Freestanding mast
Stanley wrote: ROHN 9H50 34 Foot Telescopic TV Wireless Antenna Push Up Mast Interesting suggestion. Rohn is well known to me, though I don't typically think of them for things like push-up masts. For those suggesting 6-10' of pipe, at my rooftop I get a reception cone of about 50 degrees elevation and above during the vegetated months (say, mid-March through mid-November), and about 30 degrees and above in the dead of winter, due mostly to dense tree cover that is 60-80 feet tall. So, I'd really need to get 20 feet + above the chimney (50+ feet above the ground) for a significant improvement. The suburban residential lot size doesn't leave me much to work with (no centrally-located tower, therefore no guys unless I negotiated easements with the neighbors, and Hell will never be that cold...). I doubt I could get a permit for 80' of Rohn 55. Maybe if I put a wind generator on it Thanks again, Charles ___ 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] OT: weather stations
Brice-- I'm also running weather display: http://home.comcast.net/~weatherbox/wxsc/wx.html I don't know an easy way to automagically sync the Davis clock with the tbolt other than what WD offers (LH and WD are hosted on the same Windows box, and LH whacks the clock on that box). I make sure the rain gauge is clear a few times a year. I don't have a problem with feathered visitors leaving samples in my rain gauge -- the other antennas on the roof, a discone on one mast and an eggbeater on the other, don't offer comfortable perches. Not as comfortable as the 70 foot tree across the street -- which is mostly in the due North blank spot, or the other large trees nearby. But a two-story house and an elevation mask of at least 20 degrees make those trees not an issue as far as GPS signals are concerned. 73 de Bob K6RTM in Silicon Valley -- Message: 1 Date: Fri, 3 Sep 2010 00:32:15 -0400 From: Heathkid heath...@heathkid.com Subject: Re: [time-nuts] Freestanding mast To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 1f8f92c02e434600b1354911e0b2d...@d1x25bd10 Content-Type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original Bob, Don't get me started on my Davis Instruments Vantage Pro 2 with BIRDS... and the rain bucket! ;) How many times have you cleaned yours out this year? Spiders and Wasps are the worst. But... unfortunately, my flag pole is now the weather station mount (wireless version) and it's too far away to mount my multiple GPS antennas. I run both Weather Display and VWS (and a LOT of other software for the weather station)... what are you running? Do you know of anyway to sync the timestamps of the weather station to a Thunderbolt? 73 Brice KA8MAV ___ 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.
