Re: [time-nuts] Cesium tube details
Embarrassed, and I'll admit being both ignorant and pompous. Metal is used in the ampoules. Won't go into any other details than that. Sorry Corby. Dave Carlson - Original Message - From: "Corby Dawson" To: Sent: Thursday, September 10, 2009 11:42 Subject: [time-nuts] Cesium tube details Hi, I'm changing the thread to cesium tube details! Dave, Maybe so, however I went out to the junk pile and pulled all the ovens (a wide range of vintage from early 5060A to later 5061A/B and various FTS). There were 35 of them and they all have the electrode on the top (or side for the FTS) for burning open the burst diaphragm. The only HP vintage I have not opened up is the 5071A/5061A/B mini small diameter tube. I will open one up within a week and take some PIX as well as PIX of opening up the oven. My gut instinct is that they would not have changed a tried an true method so late in the game. John Akermann has graciously offered to provide a space for me on his website to post the pictures. I'll take some PIX of other areas of the tube also while I'm in there. Best Regards, Corby Dawson Free Screensavers Incredible variety to choose from. Safe and 100% Free. Download Now! http://thirdpartyoffers.juno.com/TGL2141/c?cp=Ra6fCzoNGhO4ttwKxrhrIAAAJ1ABLZFyqoH-WnHH1GJ345whAAQFABsvXTwACBlnAA== ___ 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] 5071A tube EEPROM and tube data
Corby wrote: "I'm not saying other tubes dont have glass but HP tubes DO NOT." On what authority? That statement is categorically incorrect. To set the record straight I worked for HP and Agilent since 1977 as a technician on the 5061 and later worked on the introduction of the 5071A with the newer small-format CBT needed for that chassis. I've had direct contact with the physicists, engineers, glass-blowers, and assemblers of the CBT and have handled the components that make up a CBT. I've given presentations to Agilent Sales Engineers at neophyte seminars, given training on the physics principles of the CBT and have learned what I know from the people who created the Cesium Beam Tube. I think I know what goes inside an HP or Agilent CBT. The ampoules are glass. They are filled using a "cow" that is a string of several ampoules that are simply a bulge in the end of a glass tube. When all the ampoules are filled with exactly the correct amount of cesium, they are each "calved" off the string using a glass-blowing torch. It's a fascinating process and would not work if the ampoules were metal. Now I'll concede that at some time in the past HP may have switched their process from a metal to a glass ampoule, and you should know if you indeed pulled that oven from an older HP CBT. But don't say that HP doesn't used glass. That's absolutely wrong. They did when they were HP, and continued to do so when they became Agilent. I was there. Dave Carlson From: "Corby Dawson" To: Sent: Wednesday, September 09, 2009 14:00 Subject: [time-nuts] 5071A tube EEPROM and tube data "The HP tubes used a heated metal "burst" diaphragm not glass ampoules to" Dave, Actually, YES. I dug up the oven I had opened up and it is as I remembered. The cesium ampoule is all metal and sits upside down in the center of the "wicking" screen. The center of the burst diaphragm is welded to a post that comes out the top of the oven via an insulated feedthru. When they want to free the cesium they apply a high current thru the post and it melts a hole where the post was welded to the diaphragm. NO glass inside the wicking or inside the ampoule. I'm not saying other tubes dont have glass but HP tubes DO NOT. I'll see if I can look thru my box of ovens and if I have an FTS oven I'll cut it open and see. Corby Dawson I do have PIX of the above but nowhere to post them! Best Weight Loss Program - Click Here! http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTFoYc8NnQJkcgLgSo51uNiMATy3jTTMkZTC0ONLV4HTEeAMAime4I/ ___ 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] HP 5061 chassis parts
Chuck, Sorry to hear you're closing down, after all these years. Drop me a line some time and we can talk. Dave Carlson (formerly HP, then Agilent) - Original Message - From: To: Sent: Tuesday, September 08, 2009 19:38 Subject: [time-nuts] HP 5061 chassis parts As some of you already know, I have closed down my frequency standards business. I am in the slow process of getting rid of things. My time is not my own right now. As of right now, I have a bunch of chassis parts I am going to start with. I have some a number of things for the HP 5061s. This includes unbroken side frames, handles, rack ears, plastic battery cases, aluminum battery holders, side panels, rear panels, most of the internal micon cables (not cut, just removed), and about anything else you can think of. I have a lot of modules but am not ready to sell them until I am able to test each of them. If you interested in any of the cabinet parts, let me know off line at serv...@frequencystandards.com. Please do not put in requests for other stuff at this time. I promise I will let the list know before anything goes onto Ebay. Chuck Norton ___ 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] 5071A tube EEPROM and tube data
Corby, "The HP tubes used a heated metal "burst" diaphragm not glass ampoules to" Actually, no. Glass ampoule inside the oven, surrounded by the wicking material. Last step in the process of starting up a new tube is to use a metal pin fired into the glass ampoule, similar to firing a small cartridge with an electrical discharge. The "explosion" drives the metal "bullet" into the glass ampoule, allowing the cesium to escape into the wicking material. Dave - Original Message - From: "Corby Dawson" To: Sent: Tuesday, September 08, 2009 00:14 Subject: [time-nuts] 5071A tube EEPROM and tube data While copying the EEprom data to use with a new tube might be a copyright violation, removing the EEprom from the defective tube and using it with a replacement tube would not! It is easily removed from a small PC board mounted on one of the tubes connectors! John, There are stages in the EM. I'll see if one of the ones I removed is handy and count the stages. As far as "loose" cesium in the tube, not so much! Most of the spent cesium is trapped in gooey carbon stuff spread around the inside of the tube where the beams end up. However a nitrogen atmosphere glove box would be the best way to try any repairs. Replacing a bad ion pump might be possible this way. I used a giant tubing cutter to remove the end caps to evaluate repairing tubes. Decided the market was not there to make it worth the effort! A grinder with cutting disks is a quick way to take one apart to explore the insides. The HP tubes used a heated metal "burst" diaphragm not glass ampoules to release the cesium during the tube manufacture. Corby Free Roofing Estimates Get up to 4 free roof estimates today. No obligation! http://thirdpartyoffers.juno.com/TGL2141/c?cp=HIFSgPdu1RBgmTTs9F4m5QAAJ1ABLZFyqoH-WnHH1GJ345whAAQFACoBgz4AEhdkAA== ___ 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] Accurate 1 pps signals
Trouble with the rch is that we're never sure if the "r" term is in the real, or imaginary plane. Dave - Original Message - From: "Lux, Jim (337C)" To: "Discussion of precise time and frequency measurement" Sent: Wednesday, August 19, 2009 10:07 Subject: Re: [time-nuts] Accurate 1 pps signals > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Had > Sent: Wednesday, August 19, 2009 9:49 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Accurate 1 pps signals > > > I'm somewhat surprised that this thread has not caused that other term > for exceptionally fine measurement to crop up; the RCH > > > Ahem.. That was but one of the earthier terms I alluded to, but "common decency and state law require..." I used to work in the entertainment industry in Hollywood doing physical special effects. That group of folks seems to have a particularly rich and varied slang and jargon vocabulary, especially for relative quantitative terms, size, movement, mass among them. Probably because no one really starts out in that industry, but almost always they start doing something else, and wind up doing it, bringing their peculiar regional and craft-related terms with them. And the heritage from theater adds to it: we don't need no stinkin' engineering, we are artists, and we make up our own words for things that the rest of the civilized world calls something else.. casting off the evil work-a-day hegemony that would restrict the freedom of our ideas.Great group of folks to work with, loads of fun, but definitely a different world. Where else can you live and work in what is essentially a medieval feudal society? (They're called Screen Actors *Guild* and the Directors *Guild* and the Writers *Guild* for a reason..) ___ 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] Lifetime of glass containers
Not to charge in, but I've looked at ordinary window pane glass in very old buildings and you can actually see the rippling effect that occurred over time, showing the "flow" of the glass toward the lower edge of the pane. One presumes that the panes were relatively uniform when installed 120 years earlier. Sounds liquid to me. Dave - Original Message - From: "Hal Murray" To: Sent: Monday, June 15, 2009 12:23 Subject: [time-nuts] Lifetime of glass containers d...@uk-ar.co.uk said: > Or as someone else suggested, use a Glass container. So long as you > don't want it to last for many 100's of years, as Glass is not a > solid, it is a "super cooled fluid" and as such it flows like Ice over > time, just that it takes much much longer to do so! As best as I can tell, the glass-is-a-liquid story is bunk. http://en.wikipedia.org/wiki/Glass#Behavior_of_antique_glass I was going to ask if anybody had tried to measure it. That seems like something a time-nut would know about. The astronomers have been running tests for years. Their mirrors don't seem to sag enough to notice, and they are very good at noticing tiny distortions. -- 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] Rubidium is good for you...
Since it's in a liquid, it must be in the hydroxide or some other ionic-compound form. Who can say as to any nutritional benefits? Anyone know whether the mild radioactive decay carries over to these compounds? Dave - Original Message - From: "Magnus Danielson" To: "Discussion of precise time and frequency measurement" Sent: Friday, April 17, 2009 3:15 AM Subject: [time-nuts] Rubidium is good for you... Fellow time-nuts, You find the strangest things when just surfing around ebay: Item number: 370158541330 Is it good for you??? Cheers, Magnus - not popping the lids... ___ 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] 5062C
Um, John. Cesium is a Haz Mat. Are you prepared for all the export paperwork to do the shipment? Dave - Original Message - From: "John Miles" To: "Discussion of precise time and frequency measurement" Sent: Monday, March 23, 2009 12:53 PM Subject: Re: [time-nuts] 5062C > John, > > Is that, now unusable tube a surplus for You? I'd have some use > for it... > > (sectioned, as a display for an University lab).. > > > Predrag Dukic > University of Split > Croatia Sure, Predrag, you're welcome to it. Someone might as well get some use out of it. Send me your address offline to jmi...@pop.net, and I'll put it on the slow boat. I'm sure you know to be careful opening the tube up, as cesium is nasty stuff. -- john, KE5FX ___ 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] cs beam tube failure???
David, > I had a similar concern about a brand new 5071a I just purchased,This unit is dated may of 05 and was first powered up Jan 2 of this year.. If it's really been turned off all that time, I'm surprised that it was able to power up. Was the Ion Pump current much higher for some period of time before it came down to 6 uA? How do you know it was manufactures in May 2005? > the ion pump has remained constant at 6 ua This may be as low as it's going to get. You might try putting the 5071A in standby mode for 24 hours or so, to allow just the Ion Pump and not the Cs Oven to operate. It might bring down the internal gassing a bit. But then again that may be as low as you get. It's not abnormal, especially for older CBT, or one that has been allowed to accumulate internal vapor pressure. > but I the electron mult volt has been dropping about 1-2 volts per day > since then.it started out at 1525 and is now at 1297 and still falling This is fine, and well within expected operation. The 5071A automatically adjusts the EMult voltage to maintain the 100 nA beam current. You have plenty of room to drop without concern. The good thing is that the lower you go, the more headroom you'll have when ultimately the beam current begins to weaken and need increasing EMult to maintain. It should eventually flatten out before it starts to rise. If it does get down to 800 to 600 volts without flattening out, then it will very likely have a problem. It may be a symptom of lots of internal gassing that is getting too much background signal to the EMult dynode. No cure for that but to send it in for repair. > all the other parameters are fine but I noticed the osc freq control has > been dropping also it is now at -6.84,started out at -5.50.. This is fine. You don't have to worry until and if it gets to 50% or more. Then it's time to tune it in, which is a bit tricky. Get copies of the O&P and Service manuals from the Symmetricom web site in PDF format and you'll have many of these answers. > do you think these is a problem with this tube?it is a high perf..should still be under warranty as the manual says there is a 5 year warranty on tubes 4240 prefix.. You appear to have purchased a good 5071A. Did you buy it used? One obvious question is: Is it locked? Dave ___ - Original Message - From: "David Welch" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Friday, February 08, 2008 9:59 AM Subject: [time-nuts] cs beam tube failure??? Dave, I had a similar concern about a brand new 5071a I just purchased,This unit is dated may of 05 and was first powered up Jan 2 of this year..the ion pump has remained constant at 6 ua but I the electron mult volt has been dropping about 1-2 volts per day since then.it started out at 1525 and is now at 1297 and still falling all the other parameters are fine but I noticed the osc freq control has been dropping also it is now at -6.84,started out at -5.50..do you think these is a problem with this tube?it is a high perf..should still be under warranty as the manual says there is a 5 year warranty on tubes 4240 prefix.. have you ever run into this before?any suggestions..Thanks David ___ 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] CBT EOL
Hello, Speaking not from a physicist perspective, but from being in the business for over 20 years... The mechanism depends somewhat on the amount of flux that has been traveling through the CBT, which determines if the cesium becomes exhausted before the electron multiplier first dynoe "wears out". In general with the HP/Agilent/Symmetricom CBT there is enough getter material inside to trap contaminants well beyond the time that the cesium should run out in the oven. As long as the Ion Pump is working, internal contamination should be the minimal contributor to EOL. Whether the cesium runs out or the Electron Multiplier first dynode loses its coating is largely dependent on the amount of flux. The High-Performance CBT run at a hotter oven temperature to gain better S/N and thereby exhaust the available cesium at a faster rate. In these CBT the EOL mechanism is more likely due to that. As the cesium runs out the S/N degrades. Increasing the EM voltage can help, but eventually you're amplifying more and more noise. In the standard-performance or long-life CBT the EOL mechanism is more likely due to the first dynode of the EM becoming depleted of its coating, than buildup of internal contaminants. Dave - Original Message - From: <[EMAIL PROTECTED]> To: Sent: Monday, February 04, 2008 6:39 AM Subject: [time-nuts] CBT EOL When a CBT reaches end-of-life, is it because the source of Cs is used up? Or is it due to contamination of the electron multiplier? I've heard both as causes but wanted more info. I have a CBT with very low beam current and it keeps falling. I'm wondering if running a higher than normal EM voltage might help keep it on life-support. -Brain, WA1ZMS/4 ___ 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] 5060A acoustic noise issue
You might try Frequency Standards and Services in Colorado Springs for any parts. However installing the 5061A/B A11 Dc Oven Controller into a 5060A may not be simple. Dave - Original Message - From: "corby d dawson" <[EMAIL PROTECTED]> To: Sent: Tuesday, January 08, 2008 8:48 AM Subject: [time-nuts] 5060A acoustic noise issue Brian, I once obtained a 5060A that was used in the time and frequency lab at HP. I guess it had sentimental value to them as they kept it going long after the 5061B had come out. It had a newer tube in it and more to the point it had one of the later 5061A/B style A11 oven controller modules installed. This provides DC to the hot wire and no acoustic noise! I can't remember where they shoe-horned it in as it is a taller module than the 5060As. These A11 units are obtainable and the modification would not be daunting. Best regards, 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. ___ 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] 5060A question
Hello, Since the source of the noise is the vibration of the Hot Wire Ionizer ribbon inside the CBT it will require using something other than pressure on the outer container to snuff it out. The outer steel of the CBT is rigid. Dave - Original Message - From: "Bruce Griffiths" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Monday, January 07, 2008 9:58 PM Subject: Re: [time-nuts] 5060A question Magnus Danielson wrote: >> Hej Magnus >> >> Do you mean an active noise cancellation system?? >> > > No, you could do that too, but I was basically refering to a simple box > tuned > in size to cancel at 2 kHz. Toss in a thick cloth for additional resistive > damping. > > You could even go Helmholtz if you want. > > Simple passive cancelation. Classical acoustical approach. For 2 kHz it is > in > reasnoble sizes. > > Another thing is to put heavy lead-rubber on the metal faces to make them > less > of a resonator/radiator. That mod can be done inside the box. > > There are a whole bunch of other tricks. Pressing on the surfaces of the > whining chamber will make it stiffer and provide a higher acoustical > impedance. > Pressing using rubber blocks, from say silicon rubber, is known to work. > > Cheers, > Magnus > > Hej Magnus Its a pity that the old rho-c impedance matched high dissipation rubber method only works under water. 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] 5060A question...
Hello, With reference the 2k noise, this indeed was coming from the circuitry in the A20 Oven Controller. We also had this in early 5061A from the original A11 Oven Controller. Actually this is the Hot Wire Ionizer ribbon inside the CBT being vibrated by the ac current flowing through it. It was resolved ultimately by designing the dc Oven Controller. Dave - Original Message - From: "Sebastian Stolp" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Wednesday, January 02, 2008 1:41 AM Subject: Re: [time-nuts] 5060A question... hi brian, maybe you can aply some tiny pieces of self adheshive lead band (golfer use on putters), or hotglue flat pieces of lead on the side of the modules metal case/ housing, or directly on whatever humms inside the device. this alters the mass that swings and produces the sound. just a thought, sebastian SEBASTIAN STOLP http://www.youtube.com/sebastianstolp -- Office: +41 (0) 56 534.56.26 Goetzhuserweg 165 Mobile: +41 (0) 76 200.00.80 CH-5245 Habsburg Email: [EMAIL PROTECTED] Schweiz/Suisse/Switzerland Google Earth: 47°28'04.15''N 8°10'06.10''E - This message is intended only for the use of the individual or entity to which it is addressed and may contain information that is non- public, proprietary, privileged, confidential, and exempt from disclosure under applicable law or may constitute as attorney work product. If you are not the intended recipient, you are hereby notified that any use, dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, notify us immediately by telephone and (i) destroy this message if a facsimile or (ii) delete this message immediately if this is an electronic communication. Thank you. Am 02.01.2008 um 09:47 schrieb Poul-Henning Kamp: > In message <[EMAIL PROTECTED]>, > [EMAIL PROTECTED] writes > : > >> Since I got it working several years ago, my HP-5060A >> has a rather loud ~2KHz audible whine coming from it. >> It seems to be a result of the switching power supply >> in the A20 oven controller module. > > My units did the same thing, and I traced the sound to > one of the two high-voltage supplies and decided that > it was probably not worth the trouble... > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > [EMAIL PROTECTED] | 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. ___ 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] 5061a tech question
Hello, If you're referring to pumping down the CBT you should ensure that the +3500 Vdc HV supply is working properly and then put the 5061 in standby mode (non-operate). This allows the HV supplies to operate but not the Cs oven. It may take a few days before the Ion Pump current drops down to near 0. If there is any residual magnetic field later on when you've gotten it all re-aligned and operating normally, then the degasser is what you'll need. Dave - Original Message - From: "sebastian stolp" <[EMAIL PROTECTED]> To: "Chuck Norton" <[EMAIL PROTECTED]>; "Discussion of precise time and frequency measurement" Sent: Wednesday, February 08, 2006 7:29 AM Subject: Re: [time-nuts] 5061a tech question hello chuck, thank you for your mail - i went right into the shop for those 0,8 fuses. the thing works properly (on the quartz for the time being), the cesium has to be treated as the clock has been in a warehouse for years not being used. i have to restore the vacuum first and i'm looking for the device to do that. i believe it's the little hp degausser. sometimes one comes up on ebay. your'e still on my list to nag about the oscilloquartz 3210 thats in your posession. if i can't tempt you moneywise, perhaps you might be interested in a swap: i have a oscilloquartz/sercel eudics 3200 digital cesium frequency standard with 3 manuals (on in english) and software. maybe youre interested... here's some introduction on what i do with the cesium equipment: Sebastian Stolp. A collection of high precision clocks I started this collection in the late 1990s with a passion for the first electronic clocks from Patek Philippe in scientific equipment 19'' racks and table cases. Equipment like this at the time provided exact time for e.g. banks, insurance companies or train stations and airports worldwide. These clocks are a breed apart from what the middle-of-the-road watch- or clock collector would consider, or manage to get hold of. They were already old-tech by the time cheap radio controlled devices were mass- produced that could easily outperform the pateks on every level of precision and synchronisation. These early electronic Patek clocks are the founding part of the collection, that has expanded since. Today, the collection reaches into the field of rubidium- and cesium frequency standards and clocks, such as Hewlett Packard early rubidiums and cesiums, the HP 5065a, and the HP 5061A/B As it is a swiss collection it will also focus on swiss cesium frequency standards from oscilloquartz, former Ebauches, Neuchatel. this includes early models like the OSA 3200 and the OSA 3210, but also quartz standards (OSA 2200), because they played a important role in meeting the synchronisation requirements of the upcoming telecom industry of the early 1980ties. best regards, sebastian > --- Ursprüngliche Nachricht --- > Von: "Chuck Norton" <[EMAIL PROTECTED]> > An: "Discussion of precise time and frequency measurement" > > Betreff: Re: [time-nuts] 5061a tech question > Datum: Tue, 31 Jan 2006 15:47:46 -0700 > > Hi Sebastian: > The ones made in the eighties used a 0.8 amp fuse for the 230 volt > setting. > I know Manuals Plus has a web site and carry a lot of manuals. Don't know > if > they have this one or not. To get the most accurate manual, you should > look > look for one that covers the first 4 digits of your units serial numbers. > This is called the series number. All HP manuals have this listed on the > inside, usually on the first or second page. If you get a manual that > covers > a higher series than yours, it will have backdating information in it. If > you get one lower, it can be quite a bit different from the one you have. > They made a LOT of revisions on these and quite a few different manuals. > > Chuck > > > > ___ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > -- DSL-Aktion wegen großer Nachfrage bis 28.2.2006 verlängert: GMX DSL-Flatrate 1 Jahr kostenlos* http://www.gmx.net/de/go/dsl ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 5071 Firmware info
Raymond, True that you could benefit, but usually the rule is "not broken, don't fix". Your example of the 4433 revision is a case in point. The Ion Pump late start is a phenomenon in the early life of a CBT and not one that would be expected to plague a unit in operation for a few weeks or longer. So if it's been running just fine for months with a pre-4433, then again no reason to take it off line and upgrade. Dave - Original Message - From: "RMelkers" <[EMAIL PROTECTED]> To: "'Discussion of precise time and frequency measurement'" Sent: October 21, 2005 6:39 AM Subject: RE: [time-nuts] 5071 Firmware info Dave, Thanks for the quick response! The portion that deals with "health monitor detects and reacts to different possible error and non-error events" is a valid area for me to look at and be concerned with. (The 5071A's that I deal with are used to feed a Disciplines Frequency standard (DFS), and configured in a Primary/Standby mode, So taking one down during a training session, while I'm onsite, isn't that big of a deal.) In some of the few firmware versions paperwork I've been able to look at, it also reduces the false error/death reports. For example Firmware revision:433 "This revision improves immunity to changes in the Ion pump current that could cause interruption of operation." The prevention of, or reduction of, "interruption of operation" could be considered a valid reason to perform this firmware upgrade. I've have paper work from a cesium that was sent to the manufacture for a "overhaul and Calibration", and came back with firmware version X.3249! I do agree that just a name change is not a valid reason to change out anything. (Except maybe a marriage license!) Raimond -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dave Carlson Subject: Re: [time-nuts] 5071 Firmware info Raimond, None of the FW upgrades have any effect on the stability or accuracy of the 5071A. So you're correct. However each revision has had some minor change in the way the health monitor detects and reacts to different possible error and non-error events. Each new CBT that is shipped out has a set of the latest ROMS included as an encouragement to upgrade at that time. The most recent FW change was simply to remove "Agilent" and insert "Symmetricom" into the ID string. Certainly no reason to interrupt a working primary standard just for the upgrade. Dave Carlson - Original Message - From: "RMelkers" <[EMAIL PROTECTED]> Sent: October 20, 2005 1:56 PM Subject: [time-nuts] 5071 Firmware info Has there been any luck in finding out what each firmware revision on the 5071A accomplished? Of the 41 that I personally deal with, most have quite an old firmware installed. I have been pursuing this information for quite some time, with no luck. Without this information, I do not see a reason to upgrade any firmware in these Cesium clocks, Nor could I really recommend doing this in the future. (Why take a pill, if you don't know what it's for?") Raimond Melkers ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 5071 Firmware info
Raymond, None of the FW upgrades have any effect on the stability or accuracy of the 5071A. So you're correct. However each revision has had some minor change in the way the health monitor detects and reacts to different possible error and non-error events. Each new CBT that is shipped out has a set of the latest ROMS included as an encouragement to upgrade at that time. The most recent FW change was simply to remove "Agilent" and insert "Symmetricom" into the ID string. Certainly no reason to interrupt a working primary standard just for the upgrade. Dave Carlson - Original Message - From: "RMelkers" <[EMAIL PROTECTED]> To: "'Discussion of precise time and frequency measurement'" Sent: October 20, 2005 1:56 PM Subject: [time-nuts] 5071 Firmware info Has there been any luck in finding out what each firmware revision on the 5071A accomplished? Of the 41 that I personally deal with, most have quite an old firmware installed. I have been pursuing this information for quite some time, with no luck. Without this information, I do not see a reason to upgrade any firmware in these Cesium clocks, Nor could I really recommend doing this in the future. (Why take a pill, if you don't know what it's for?") Raimond Melkers AFSPC SMC MCL //L-3 Comm Titan Corporation 719-930-8011 [EMAIL PROTECTED] ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] eBay: HP Cesium Beam Tube Hewlett Packard 1924A 029090581
Jack, See the thread below on this CBT, if it's indeed the same one. Dave - Original Message - From: "Dave Carlson" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: September 08, 2005 1:44 PM Subject: Re: [time-nuts] Cesium beam tube on eBay Based on data I have, it pre-dates March 1986. Unfortunately the earliest serial number I have is 3156 (last 4 digits) so not extremely accurate. This is definitely an old CBT and would be surprising if it had any life at all. BTW the 1924A does indeed indicate 1979 and the 24th week, but please remember that this is the yyww of the last significant engineering change to the model number. The 1924A prefix remained unchanged until the 3232A prefix (smaller-diameter CBT), over 13 years later, so not a good indicator of age, at all. Dave Carlson - Original Message - From: "Bdale Garbee" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Thursday, September 08, 2005 7:10 AM Subject: Re: [time-nuts] Cesium beam tube on eBay > On Thu, 2005-09-08 at 09:57 +0200, Magnus Danielson wrote: >> serial number 1924A02909 > > If I recall correctly, HP serial numbers of that vintage are YYWWCN. > > YY is the year expressed in years since an epoch, usually 1960. So 19 > means 1979. > > WW is the week of the year in which the last manufacturing change was > made. > > C is the manufacturing location, A means USA. > > N is a sequential unit number. > > Bdale > > ___ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Other HP 10x manuals (was HP 107BR)
In reference to: "Curiously, Agilent's obsolete PDF index lists the 105B as sold to Symmetricom, although they don't have it on their website. Presumably they have killed it as a product since it competes directly with the 1050A they sell already." Actually the 105B just went out of support (~July 2005) so it was already not in active production at the time of the acquisition. That means that Symmetricom did not kill the 105B, it was already obsoleted when acquired. Just setting the record straight. Dave Carlson - Original Message - From: "David Forbes" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Thursday, September 15, 2005 9:49 AM Subject: Re: [time-nuts] Other HP 10x manuals (was HP 107BR) I have a problem with my old faithful standard, an HP 107BR. The regulated voltages are zero, although the raw +46 is there. Anyone have a power supply schematic I could set a copy of? Well aged standard. It did better than 30 years service in our Paumalu Hi Intelsat earth station before moving the K1YCM/3 for additional service. Thanks Les Les, Sorry, I do not have that manual on hand. However, if anyone's interested, I have manuals for the following HP timepieces: 103AR quartz oscillator 105A/B quartz oscillator 113BR mechanical clock (a rare bird and a fascinating manual) and the Efratom FRK rubidium source. The above manuals were all salvaged by an astute engineer here at Steward Observatory as NRAO's local office is moving itself from Tucson to Charlottesville VA. I'd be happy to scan these as time permits to get them on the Web, since they do not appear to be currently viable products for Agilent and the manuals aren't available as scans anywhere that I know of. I'd want to talk to the Agilent fellow first to see what he thinks. Curiously, Agilent's obsolete PDF index lists the 105B as sold to Symmetricom, although they don't have it on their website. Presumably they have killed it as a product since it competes directly with the 1050A they sell already. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Cesium beam tube on eBay
Based on data I have, it pre-dates March 1986. Unfortunately the earliest serial number I have is 3156 (last 4 digits) so not extremely accurate. This is definitely an old CBT and would be surprising if it had any life at all. BTW the 1924A does indeed indicate 1979 and the 24th week, but please remember that this is the yyww of the last significant engineering change to the model number. The 1924A prefix remained unchanged until the 3232A prefix (smaller-diameter CBT), over 13 years later, so not a good indicator of age, at all. Dave Carlson - Original Message - From: "Bdale Garbee" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Thursday, September 08, 2005 7:10 AM Subject: Re: [time-nuts] Cesium beam tube on eBay On Thu, 2005-09-08 at 09:57 +0200, Magnus Danielson wrote: serial number 1924A02909 If I recall correctly, HP serial numbers of that vintage are YYWWCN. YY is the year expressed in years since an epoch, usually 1960. So 19 means 1979. WW is the week of the year in which the last manufacturing change was made. C is the manufacturing location, A means USA. N is a sequential unit number. Bdale ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Cesium beam tube on eBay
Yes, 05061-6077 is the Standard Performance CBT. can anyone read any part of the serial number? It might help to narrow down the age. The last 5 digits are actually more important than the first 4 before the "A". Dave - Original Message - From: "Magnus Danielson" <[EMAIL PROTECTED]> To: ; <[EMAIL PROTECTED]> Sent: September 07, 2005 12:02 PM Subject: Re: [time-nuts] Cesium beam tube on eBay From: "Dr. David Kirkby" <[EMAIL PROTECTED]> Subject: [time-nuts] Cesium beam tube on eBay Date: Wed, 07 Sep 2005 14:15:34 +0100 Message-ID: <[EMAIL PROTECTED]> > This might interest someone. > > http://cgi.ebay.com/HP-Cesium-Beam-Tube-Hewlett-Packard-1924A-02909-0581_W0QQitemZ7543746172QQcategoryZ25399QQrdZ1QQcmdZViewItem > > The description of how it was obtained is interesting. > > "I got this from a scrap yard. The folks there save vacuum tubes for me and when they saw "tube" on > this they pulled it out of the test set. I don't see any cut wires so it looks like they unhooked it. > It is about 15 by 5 1/2 inches. " > > I'd hate to guess the value of the item they destroyed to pull the "tube" for him!! Somebody tossed an HP 5061 on the scrap-yard. Look up the value of an HP 5061 in unknown condition and there you are. Chances are the tube is gone. On page 6-18 of the HP 5061A service manual you find it listed as the Cesium Beam Tube Assembly, reference designation A12 if you care. From the looks of it this is the standard performance tube. HP X-6Y is parts of HP X. HP X-9 is manuals for HP X. Usefull rought pointer derived from "On the large label is has part number 05061-6077". Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] rubidium standard caveats?
If you are looking at an old HP 5065A it may well be a very noisy reference by now. Dave - Original Message - From: "Christopher Hoover" <[EMAIL PROTECTED]> To: Sent: August 15, 2005 6:59 PM Subject: [time-nuts] rubidium standard caveats? hi folks. i intend to buy a used rubidium standard (10MHz preferrably), probably off of e-bay. a few questions for you gurus: any models that are especially winning? any models i should avoid? other caveats? thanks, christopher. ch<<<>>>murgatroid<<<>>>com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] am, m, pm and ?
This is something that I've wondered about. I know that someone out there will know or at least have an opinion. It's generally agreed that time between midnight and noon is expressed as hh:mm:ss with the "am" suffix for "ante meridian" (yes, I'm keeping this discussion to a 12-hour clock). Also of course that times from noon to midnight are expressed as hh:mm:ss with the "pm" suffix for "post meridian". Also I've heard that noon is known as meridian or "m" and that the time 12:00:00 exactly could have the "m" suffix, even if this time only exists for a brief moment, loosely speaking. What I'm wondering is what do we call midnight, given these conventions? The time 00:00:00 is not really pm or am, as are 11:59:59 pm and 00:00:01 am are. Somehow saying 12:00:00 am sounds inconsistent. Is there perhaps some archaic suffix that was or is used to denote exact midnight, just as "m" is used to denote exact noon? Dave Carlson ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Symmetricom 5071A
Hello Magnus, Your question: "Or, to put it in another form, do you know where the HP/Agilent tubes are actually made (I.he. not the total clock assembly)?" Since the early 1970s made in Santa Clara CA, corner of Stevens Creek Blvd and Lawrence Expressway, at the site once owned by HP and later by Agilent. Before that they were made by HP in Palo Alto, Ca. Never has Symmetricom or any other CBT manufacturer made CBTs for HP or Agilent. HP/Agilent always made their own. Other CBT manufacturers have made a CBT that could be retrofitted into a 5061A/B Cesium Beam Frequency Standard, but not the 5071a. Dave Carlson Message - From: "Magnus Danielson" <[EMAIL PROTECTED]> To: Sent: June 25, 2005 1:11 PM Subject: Re: [time-nuts] Symmetricom 5071A From: "Dave Carlson" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Symmetricom 5071A Date: Sat, 25 Jun 2005 12:42:48 -0700 Message-ID: <[EMAIL PROTECTED]> > Hello Magnus, Hi Dave, > No. Symmetricom NEVER made the tube for the 5071A. Please tell me where you > got that. I'll check with my source. He pointed out this fact to me last year. Naturally, I could have got him wrong, or he could have his facts wrong. > The HP/Agilent 10890A and 10891A CBTs could not be legally re-engineered and > the 5071A chassis required that the CBT installed be only one from > HP/Agilent. You interprent what I said as it is the same tube, I did not say that. What my source said was that they where manufactured by Symmetricom. Or, to put it in another form, do you know where the HP/Agilent tubes are actually made (i.e. not the total clock assembly)? Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Symmetricom 5071A
Hello Magnus, No. Symmetricom NEVER made the tube for the 5071A. Please tell me where you got that. The HP/Agilent 10890A and 10891A CBTs could not be legally re-engineered and the 5071A chassis required that the CBT installed be only one from HP/Agilent. Dave carlson - Original Message - From: "Magnus Danielson" <[EMAIL PROTECTED]> To: ; <[EMAIL PROTECTED]> Sent: June 25, 2005 4:45 AM Subject: Re: [time-nuts] Symmetricom 5071A From: "Poul-Henning Kamp" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Symmetricom 5071A Date: Sat, 25 Jun 2005 09:59:41 +0200 Message-ID: <[EMAIL PROTECTED]> > In message <[EMAIL PROTECTED]>, "Tom Van Baak" writes: > >Symmetricom to Acquire Agilent Technologies' Frequency and Time Standards > >Product Line > > > >http://biz.yahoo.com/prnews/050624/sff034.html?.v=13 > > So now we have a Cesium monopoly ? Not a really big change, since they already made the tubes for the 5071A. Also, there is still one Symmetricom independent (except for the tubes) vendor in Oscilloquartz. Actually, this will be more buissness to them, since Symmetricom again is remaking its mistake of bringing many small buissess to one larger one, just to loose orders to the competition (Oscilloquartz) since they removed the second-source orders. Now they are doing it again. Ah well. I have long wondered where the Cesium line (sorry, no pun intended) of Agilent is going to end up, since it is becomming more and more of an obscure product in their reshaping/downsizing. They basically had two potential buyers, Symmetricom and Oscilloquartz and they already sold their GPS clock buissness to Symmetricom so I guess it was the easiest path. There is also the Russian/English clockmaker (Cesium and Hydrogen) but they have yeat to make a big impact on the western market as far as I've have gathered their dealings. In the western world, at least for commercial tubes, there have been only one tube vendor for a long time now, so you could view that as a monopoly in itself. On the other hand, considering that this is not really a mass-market I guess it makes sense anyway. They also do tubes in Russia to the best of my knowledge. Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Strange connectors
Twin-ax BNC. Trompeter carries them, last I heard. Dave - Original Message - From: "Bill Hawkins" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Monday, 20 June, 2005 9:45 AM Subject: [time-nuts] Strange connectors Telco equipment has a BNC shell over a two pin connector for shielded twisted pair. The connector is keyed by different heights for the two pins. I haven't found it because I don't know what to call it. Pasternak? Bill Hawkins ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] glossa7 being whiney on eBay...
John, Yes, I would prefer that. - Original Message - From: "John Ackermann N8UR" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>; "Discussion of precise time and frequency measurement" Sent: Wednesday, 15 June, 2005 5:50 AM Subject: Re: [time-nuts] glossa7 being whiney on eBay... Brian Kirby wrote: > I seen the ad's on E-bay yesterday. > > Since I had dealings with him, and made comments to this group about the > dealings, and the fact another person had the same dealings, I stand > byside what I said. > > Our post show up in a lot of search engines - Something to consider > before you comment. Probally from the stored archives. > > Brian - N4FMN I *think* (but am not certain without a little research) that I can structure the list archives to be private and accessible only to subscribed members. I know that Mailman allows private archives for private lists, but I'm not sure if a publicly visible list can have a private archive. If there's a consensus to do that, I'll see what I can do. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] hp5061A questions
I agree with Chuck. Also keep in mind that not only does the A4 perform the function of matching the internal CBT microwave cavity with the outside world with a high degree of temperature compensation, the input side of the A4 used a SRD to generate a hash of sidebands from the input 90 MHz, from which one and only one sideband was selected. thus the name "Harmonic Generator". It's a fascinating piece of machined metal and electronics, and is a conversation piece when employed as a paperweight. Dave Carlson - Original Message - From: "Frequency Standards & Services" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Wednesday, 01 June, 2005 12:31 PM Subject: RE: [time-nuts] hp5061A questions Hi David: It isn't so much that the equipment is rare or hard to find, it is just knowing how to tune them and what to look for when you do. One example of getting one tuned wrong, you will still get a good signal out of it but the temperature range that the unit will operate in will be drastically reduced. You will find that small room changes in the room temperature will cause serious changes in your stability and sometimes even make them break lock. I have attended the class that HP used to give on tuning them and I have a set up for completely rebuilding them. Unfortunately, anymore, it is almost cheaper to just find someone with a cesium with a bad tube and buy the Harmonic Generator from them. On the other hand, if you just want to experiment with one and see what happens, as long as you have a known good unit to put back in when you are done, it probably wouldn't hurt anything. Just don't experiment with the only one you have. As you probably recall from working with wave guide screws, a tiny movement can make a huge difference in output, frequency, etc.. Chuck Norton Frequency Standards & Services 2727 E. Palmer Park, Ste. 100 Colorado Springs, CO. 80909-3032 719-228-0540 voice 719-228-9009 fax -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of David Kirkby Sent: Wednesday, June 01, 2005 1:15 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] hp5061A questions Dave Carlson wrote: > Absolutely. Especially don't mess with any of the mechanical adjustments on > the A4 harmonic generator that is attached to the CBT. These are aligned to > resonate exactly to 9.192 GHz and it would be almost impossible to realign > one without using a special waveguide tuning fixture. Only a few of the > extrusions are intended for matching the A4 to each individual CBT. > > If you've already turned some of the knurled screws, nuts, knobs, and hex > screws, you may never be able to capture the correct resonant peak, even if > you can get the cesium oven to start working. > > The best remedy to a mis-aligned harmonic generator is to find another one > that has not been adjusted and attach it to your CBT, or send it to someone > with the correct waveguide fixture. > > Dave Carlson As a matter of interest, from someone who knows next to zero about cesium sources, but a reasonable amount about radio frequency and microwave engineering, what does the waveguide tuning fixture do? What is so special about it? Could an amateur fabricate one? X-bade rectangular waveguide suitable for 9.192GHz is easy to come by (known in the UK as WG16, but also as WR80 and RG52). I used that very waveguide as a child in a 10GHz amateur radio system with a Gunn diode. Tuning of waveguide components can be achieved by inserting screws in the side - again not too hard to fabricate. My guess (and note I have never seen a cesium source) is that the waveguide fixture would temporarily be part of the cavity, so if the dimensions of that fixture were known, it would not be hard to make it oneself with access to a milling machine, or get a small engineering company to do it. I appreciate from reading what you have said that not touching the assembly is the best idea, but if someone has "tweaked" one, I would not have thought getting the cavity back on resonance would be hard, given a few physical dimensions, and a microwave power meter. Waveguide to N adapters are pretty easy to fabricate too, although again I suspect they can be bought used for very little. And microwave power sensors with N connectors are easy to come by, or again could be made easily. Just more curious than anything else, as I don't have a cesium source, and don't feel I will ever become a real "time-nut" and get one. Soon I should have my bit of kit built which will have both a 10811-60111 and a Standford PRS10 both locked to GPS. I'm sure the two oscillators will drift relative to each other, so I know I'm going to be questioning which is the most stable, but I think I will stop be
Re: [time-nuts] Re: 10811 serial numbers
Well, You learn something new every day. Since these are the 10811A they are the first of the model pairs (A/B and D/E) to come out in the 10811 model line. It is entirely possible that engineering decided to not include the prefix for those. It's a departure from the standard format for serial numbers from HP in those days, and I suspect that later the standard format was re-introduced. After all, without the prefix, it's pretty hard to pin down the general age of the product and what changes were present. Dave Carlson - Original Message - From: "Javier" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Wednesday, 01 June, 2005 8:08 AM Subject: Re: [time-nuts] Re: 10811 serial numbers I've a 10811A with s/n A00591, no prefix, also a A01096, no prefix, and the label in both units is an original HP one, looking the same as the labels I've on some 10544As with 1436A prefix. So I think that 10811A oscillators with no prefix on the serial number are not so strange. Regards Javier, EA1CRB lberto di Bene wrote: > Dave Carlson wrote: > >[...] >I can't say where that strange "A03912" number came from, except that it may >have been a separate asset number added to that oscillator by the previous >owner or that as a result of a previous repair a new label was generated as >a replacement and the prefix was not considered relevant. > > > Dave, > thanks for your clarification. Looking at the unit, it seems to me > that the label with the S/N is the original > one placed on the OCXO by the manufatcturer, but of course I could be > wrong. This is a photo of the > oven oscillator in question. > 73 Alberto I2PHD > > > > > >___ >time-nuts mailing list >time-nuts@febo.com >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] hp5061A questions
Chuck wrote: One last word of advice...DON'T adjust ANYTHING on the unit until you have figured out where your problem is. If you have a really good standard already then you could use it to check the oscillator with and adjust it but other wise, leave it where it is for now. Absolutely. Especially don't mess with any of the mechanical adjustments on the A4 harmonic generator that is attached to the CBT. These are aligned to resonate exactly to 9.192 GHz and it would be almost impossible to realign one without using a special waveguide tuning fixture. Only a few of the extrusions are intended for matching the A4 to each individual CBT. If you've already turned some of the knurled screws, nuts, knobs, and hex screws, you may never be able to capture the correct resonant peak, even if you can get the cesium oven to start working. The best remedy to a mis-aligned harmonic generator is to find another one that has not been adjusted and attach it to your CBT, or send it to someone with the correct waveguide fixture. Dave Carlson - Original Message - From: "Frequency Standards & Services" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>; "Discussion of precise time and frequency measurement" Sent: May 26, 2005 2:32 PM Subject: RE: [time-nuts] hp5061A questions Hi George: You have a pretty common problem with used cesium's. The first thing to do would be to look and see if the ion pump current is very high. If it is, the cesium oven will not turn on. Until the cesium oven is on and operating at normal temperature, you cannot get any 2nd harmonic or beam current. The oven should indeed be on all of the time. You will not feel a great deal of heat on the tube though since it is a double walled tube. There isn't a test point that you can measure to tell if the oven is working correctly since it isn't a simple DC voltage that is applied to the heater circuit. It is a bridge circuit that uses the heater, a thermistor and some resistors to balance the tube out at the right temperature. The tube would have to have been handled pretty rough to have damaged the heater element. I wont say it can't happen but isn't likely to be the problem. I am not aware of any web sites that have a manual on them. Perhaps someone else in the group knows of one. I have several "check" procedures that I can send you if you want to e-mail me direct. They are probably more than what we should post on this board. They give you steps to check out the unit and tell if you have a probable bad tube or if there is something else wrong. One last word of advice...DON'T adjust ANYTHING on the unit until you have figured out where your problem is. If you have a really good standard already then you could use it to check the oscillator with and adjust it but other wise, leave it where it is for now. Chuck Norton Frequency Standards & Services 2727 E. Palmer Park, Ste. 100 Colorado Springs, CO. 80909-3032 719-228-0540 voice 719-228-9009 fax -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of george Sent: Thursday, May 26, 2005 10:27 AM To: time-nuts@febo.com Subject: [time-nuts] hp5061A questions I just got my first Cesium atomic oscillator (hp5061A) please help! I dont have a meter reading for the CS oven and believe the oven is not functioning. The cs oven controler switch is on and set to normal temperature. Shouldn't the CS oven be on all the time like the quartz oven or are there other signals required before the cesium beam oven activates? And shouldn't I be able to feel heat from the Cesium beam case indicating oven operation? I also have no 2nd harmonic or control readings, all other reading seem ok, what frequency would the second harmonic be? I see some test points on a pcb interconnect strip under the bottom cover ie 18 v 18v 18v 25-30v synth control 1mhz 100khz control. are these control, control test points the same as the mult-meter control measurement or are these all seperate control voltages for other functions? All voltage test points are good. I didn't check synth, or control test points fearing that a high impedance vtvm would be required Could someone point me to the supply point for the Cs oven heater voltage or possibly describe the heater element itself? Is it delicate enough that coast to coast shipping could have opened the element? Are there any online documentation for the hp5061 I can use before obtaining a service manual? Also on the cs controler is a pot adjustment labled Mass Spect. What is this adjustment for. Thanks for listening. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.co
Re: [time-nuts] 10811 serial numbers
A clarification: The 4-digit prefix preceding the "A" or following the "US" in newer units is indeed based on 1960 and a 28xx refers to 1988. However it is the year/week of the most recent engineering change documented. The last 4 or 5 digits are a sequential number that is unaffected by the serial prefix. Therefore a 2850A or US2850 prefix does not necessarily mean that it was manufactured in the 50th week of 1988. It does means that it could not have been manufactured earlier than that date. The only way to know the upper boundary is to know the next serial prefix assigned to the next engineering change. Usually service manuals provided this information in the backdating and change sheets, but for non-field-repairable oscillators this information was not readily available. The changeover to the unusual 4-digit code given in this thread of messages is not the result of the HP/Agilent spin-off. Agilent continued to use the prefix/suffix nomenclature for its oscillators after its operation as a separate company. I can't say where that strange "A03912" number came from, except that it may have been a separate asset number added to that oscillator by the previous owner or that as a result of a previous repair a new label was generated as a replacement and the prefix was not considered relevant. I also know of no tamper-proof labels used on the 10811 series oscillators. Dave Carlson - Original Message - From: "John Miles" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: May 26, 2005 11:13 AM Subject: RE: [time-nuts] 10811 serial numbers > BTW, does anyone know if the 10811-series oscillators had any 'tamper > resistant' label of any form, such that if one was missing, you could > reasonably assume someone has taken it apart at some time? None of them I have seen has anything like that. -- john KE5FX ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Lifetime of Cesium tube
From the Agilent perspective, the expected lifetime of a new 05061-6101 High Performance CBT is an average of 5 to 6 years of continuous operation. We don't speculate on non-operating useful life. Lifetime is not a specification for a number of reasons. The 5061A/B electronics are not microprocessor-controlled as in the 5071A so there are fewer guards against the possibility of a CBT being operated outside of its nominal range of Cs oven temperature, EMult voltage, HWI voltage, etc. Any of these could have an effect on CBT lifetime. Agilent is still manufacturing and selling the replacement CBT for the 5061A/B as products with model numbers 05061-6101 and 05061-6077 (standard-performance). N.B. that in order for the CBT warranty to be valid for these models it is stipulated that it be operated only in conjunction with the newer A11 Cs Oven Controller, identified as HP P/N 05061-6144. CBTs manufactured after December 2002 now have more Caesium to extend their expected operating life. This is true for all four of our CBT models, the aforementioned two above as well as the 10890A and 10891A models for the 5071A Primary Frequency Standard. Although there is little or no empirical data for the improvement in the 05061-6xxx models, initial testing results on the 10891A model give expectations that the lifetime will average 9 to 10 years instead of the previous 6 years. To back up that improvement Agilent also increased the warranty on that model 10891A to 5 years. These newer CBTs with increased quantity of Caesium are denoted by the following serial number prefixes: 05061-6077US4247 5-year warranty 05061-6101US4248 3-year warranty 10890A US4239 10-year warranty 10891A US4240 5-year warranty HP presented a paper at the Frequency Control Symposium in 1999 that described lifetime and end-of-life symptoms, geared toward the 5071A. Here are the first several lines, to help in searching for the document: "LONG-TERM EXPERIENCE WITH CESIUM BEAM FREQUENCY STANDARDS John A. Kusters, Hewlett-Packard Santa Clara, USA Leonard S. Cutler, Hewlett-Packard Laboratories, USA Edward D. Powers*, United States Naval Observatory, USA ABSTRACT Since its introduction 7 years ago, the Hewlett-Packard cesium beam frequency standard has been installed in many national laboratories. At the present..." As to pumping down a CBT in non-operating storage, the recommendation in the 5071A Operating manual is that it be done every 6 months. This applies a conservative approach because in addition to time causing eventual increase in internal vapor pressure, temperature also has an impact. A CBT or Cs standard stored un-powered in a very cool environment will have less likelihood of this than one stored in a galvanized-metal warehouse in full sunshine. Every 6 months is a good rule of thumb. As to pump-down procedures, Appendix B in the 5061B Operating/service manual tells how to use an external HV supply to pump the CBT by itself, should the HV supply installed in the instrument chassis fail to do the job. Dave Carlson Original Message - From: "Chuck Harris" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" Sent: Thursday, 12 May, 2005 5:36 AM Subject: Re: [time-nuts] Lifetime of Cesium tube > glenn.tracy wrote: > > What kind of lifetime can one expect to see from an HP 5061-6101 cesium > > tube? > > It is my understanding that you can expect about 5 years in continuous use, > or 2 years on the shelf. > > > What typical symptoms do these exhibit near the end of their useable > > lifetime? > > The end of life can be due to several things, but most notable is a shortage > of cesium ions to send hurling down the length of the tube, and an excess > of other molecules for the cesium ions to run into. Either condition results > in a shortage of cesium molecules for the detector to detect. > > A c-beam is essentially a notch filter. The beam is modulated (mixed?) with > a 9Ghz microwave signal that is derived from a very stable and low noise crystal > reference. When the modulation signal is at the right frequency, the beam > current will peak. There is usually a servo mechanism that keeps the crystal > reference tuned so that the beam current stays on top of this peak. > > At end of life, the beam current peak becomes indistinct. There isn't much > distance between the peaks and the valleys, and the servo has trouble figuring > out where the peak is, so it ends up bouncing all over the place. This shows > up as increased phase variations. Ultimately, no peaks can be found and the > crystal oscillator ends up slammed against its maximum, or minimum frequency. > > -Chuck > > ___ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
