Re: [time-nuts] time-nuts Digest, Vol 36, Issue 30
In a message dated 7/17/2007 20:37:33 Pacific Daylight Time, [EMAIL PROTECTED] writes: (Which store??) I'm interested. I'm in Los Gatos (Pollard Road). I can pick it up, but only through Friday of these week. > List member (presumably an unmarried one)? > http://farm1.static.flickr.com/70/188117595_213c635851.jpg?v=0 Yeah, presumably unmarried. My wife expressed a certain appreciation of the aesthetic of that décor, but was not keen that we adopt it.(But she does like nixie tubes, so there's still some hope for me.) -ch It's yours! I'll contact you offline to set it up. thanks, Said ** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour ___ 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] time-nuts Digest, Vol 36, Issue 30
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] > I have a nice old Dixie tube HP5532A counter to give away that I picked > up > at a local recycling store. It powers up, and I can coax it to count. > It needs > a little cleaning, and some love. I figure someone collecting these > would > have good use for it. > > Let me know if you want it, > thanks, > Said (Which store??) I'm interested. I'm in Los Gatos (Pollard Road). I can pick it up, but only through Friday of these week. > List member (presumably an unmarried one)? > http://farm1.static.flickr.com/70/188117595_213c635851.jpg?v=0 Yeah, presumably unmarried. My wife expressed a certain appreciation of the aesthetic of that décor, but was not keen that we adopt it. (But she does like nixie tubes, so there's still some hope for me.) -ch ___ 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] HP5532A for free
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: > In a message dated 7/17/2007 19:12:15 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > >> My old HP 523C does not have Nixie-tubes, such modern shit. No, it uses >> > pure > >> neon lamps which light up a little display of 0-9. :) >> I only have a 5-digit one, but there are others that had 6 digits. >> > > > > I have an old Nixie tube desktop calculator somewhere, it uses diodes as the > active calculating elements. DCL they called it I think. Wow. It's got some > 6 digit precision if I remember correctly. > > I can see a blue glow inside some of the Nixie tubes, I am sure those tubes > generate IR, X-ray and all sorts of other stuff that makes the mice die > around > the house... > > bye, > Said > > Said The operating voltage isn't high enough to generate X-rays. There may be a slight amount of IR from neon however. 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] HP5532A for free
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] From: [EMAIL PROTECTED] Subject: Re: [time-nuts] HP5532A for free Date: Tue, 17 Jul 2007 22:20:32 EDT Message-ID: <[EMAIL PROTECTED]> > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] > > > In a message dated 7/17/2007 19:12:15 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > > >My old HP 523C does not have Nixie-tubes, such modern shit. No, it uses > pure > >neon lamps which light up a little display of 0-9. :) > >I only have a 5-digit one, but there are others that had 6 digits. > > > > I have an old Nixie tube desktop calculator somewhere, it uses diodes as the > active calculating elements. DCL they called it I think. Wow. It's got some > 6 digit precision if I remember correctly. Wow! I have a drum-machine with a sequencer operating that way, but no counter. Having seen Zuse Z3 in action brings you perspective. :) 22 bit floating point in relays. :) Let's see if we can't get something similar out of DCL. Now where's that bag of 1N4148 I bought a few years back! :) > I can see a blue glow inside some of the Nixie tubes, I am sure those tubes > generate IR, X-ray and all sorts of other stuff that makes the mice die > around > the house... IR yes - some, bring your palm up and feel the heat. But the tubes inside is better at it. X-ray - no much really. Too low voltage (150 V?) to really become a hazard. Those TV-tubes you smashed as a kid was running as high as 25 kV and that is the normal limit, but the thick glas is there for a reason. If the mice dies around the house, suspect the neighbor cat of not doing its job propperly, if they only disappear be happy about him or her not being THAT lazy. :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP5532A for free
List member (presumably an unmarried one)? http://farm1.static.flickr.com/70/188117595_213c635851.jpg?v=0 -- john, KE5FX > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Behalf Of [EMAIL PROTECTED] > Sent: Tuesday, July 17, 2007 7:15 PM > To: time-nuts@febo.com > Subject: Re: [time-nuts] HP5532A for free > > ___ 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] HP5532A for free
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] In a message dated 7/17/2007 19:12:15 Pacific Daylight Time, [EMAIL PROTECTED] writes: >My old HP 523C does not have Nixie-tubes, such modern shit. No, it uses pure >neon lamps which light up a little display of 0-9. :) >I only have a 5-digit one, but there are others that had 6 digits. I have an old Nixie tube desktop calculator somewhere, it uses diodes as the active calculating elements. DCL they called it I think. Wow. It's got some 6 digit precision if I remember correctly. I can see a blue glow inside some of the Nixie tubes, I am sure those tubes generate IR, X-ray and all sorts of other stuff that makes the mice die around the house... bye, Said ** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour ___ 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] HP5532A for free
In a message dated 7/17/2007 18:56:56 Pacific Daylight Time, [EMAIL PROTECTED] writes: >I just found it amusing. It's a very kind offer you are making, but not >something I can find room for. >I think we are very close in location. I am near Bascom and Hamilton on >the S.J., Campbell border. If I shout out of my window, you will hear me. I'm on Winchester and Campbell :) ** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour ___ 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] HP5532A for free
From: Rex <[EMAIL PROTECTED]> Subject: Re: [time-nuts] HP5532A for free Date: Tue, 17 Jul 2007 18:33:18 -0700 Message-ID: <[EMAIL PROTECTED]> > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] > > On Tue, 17 Jul 2007 21:19:40 EDT, [EMAIL PROTECTED] wrote: > > >Dixie tube > > An old neon tube display for those South of the Mason-Dixon line? > (vs. Nixie tube for those North.) > > Sorry, couldn't resist. I thought Dixie tube was a feature on the steam engine on one of those Mississippi boats. My old HP 523C does not have Nixie-tubes, such modern shit. No, it uses pure neon lamps which light up a little display of 0-9. :) I only have a 5-digit one, but there are others that had 6 digits. I have the deluxe variant with a CRYSTAL OSCILLATOR. 100 kHz. Phantastron dividers. The normal version has a Phantastron divider which you tune for a divide by 5 or 6 depending on 50 or 60 Hz. That divider is set for 10 when having the crystal oscillator assembly. As I recall it, the Phantastron uses up a penthode and diode, but since double-diode tubes is used the tube count isn't that high. The fun thing is that IT STILL WORKS! Maybe not as high in frequency as it is supposed to (it seems to garble things up at 120 kHz but it should handle 220 kHz or so since it has the high speed (!) counters in it. It has a thad lower singel shot resolution compared to the 5370B and Wavecrests. I scored a Marconi Nixie counter while dumpster-diving. Also works but it had some minor issue as I recall it. Last friday I tune up a friends 5243L and succsesfully counted 490 MHz with the module. It has a large oven which was out of tune, but it was easy enought to tune it up. He also has the 3 GHz and 12.4 GHz modules that is only supposed to go into the 5245L, as the counter needs slightly more than 50 MHz counting range and the 5243L is limited to a little more than 30 MHZ. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP5532A for free
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] On Tue, 17 Jul 2007 21:47:30 EDT, [EMAIL PROTECTED] wrote: > >In a message dated 7/17/2007 18:32:51 Pacific Daylight Time, [EMAIL PROTECTED] > >writes: > >>An old neon tube display for those South of the Mason-Dixon line? >>(vs. Nixie tube for those North.) > >>Sorry, couldn't resist. > > > >As you can see I REALLY don't know anything about this unit, not even how to >spell the thing :) > >I grew up with Atari etc, and the most exposure to tubes I had was when we >would go around smashing old tube-based TV's during trash pickup as kids. > >Kind of unfortunate how all that knowledge just evaporates... > >bye, >Said > I just found it amusing. It's a very kind offer you are making, but not something I can find room for. I think we are very close in location. I am near Bascom and Hamilton on the S.J., Campbell border. ___ 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] HP5532A for free
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] In a message dated 7/17/2007 18:32:51 Pacific Daylight Time, [EMAIL PROTECTED] writes: >An old neon tube display for those South of the Mason-Dixon line? >(vs. Nixie tube for those North.) >Sorry, couldn't resist. As you can see I REALLY don't know anything about this unit, not even how to spell the thing :) I grew up with Atari etc, and the most exposure to tubes I had was when we would go around smashing old tube-based TV's during trash pickup as kids. Kind of unfortunate how all that knowledge just evaporates... bye, Said ** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour ___ 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] HP5532A for free
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] On Tue, 17 Jul 2007 21:19:40 EDT, [EMAIL PROTECTED] wrote: >Dixie tube An old neon tube display for those South of the Mason-Dixon line? (vs. Nixie tube for those North.) Sorry, couldn't resist. ___ 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] HP5532A for free
Hi guys, I have a nice old Dixie tube HP5532A counter to give away that I picked up at a local recycling store. It powers up, and I can coax it to count. It needs a little cleaning, and some love. I figure someone collecting these would have good use for it. The first responder to this email will get it for only the shipping cost, but in order to keep my effort reasonable, I need to ask for the following please: * A US ship-to address * A Fedex account number to ship against. I will package it and send it against your account for free. Cannot do UPS, USPS etc unfortunately. Local pickup is ok too. * I don't know anything about the instrument, and don't have any manuals, so cannot help BTW: the warranty expired in 1967, so no chance getting Agilent to help :) Let me know if you want it, thanks, Said ** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour ___ 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] Oncore VP problem
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] In a message dated 17/07/2007 23:09:36 GMT Daylight Time, [EMAIL PROTECTED] writes: You should be able to restart the VP with the @@Cg command in the "Additional Message Window" in WinOncore12. The total command string is: @@Cg01. Note that with the VP this must be done after every receiver default or SelfTest. -- You will also encounter trouble trying to run a lot of the more esoteric 8 channel messages that the VP supported. WinOncore12 has no idea about what to do with these. Once again, Rick's software will come to the rescue. Best regards, Randy Warner Senior Applications Engineer Geodetics, Inc. --- Thanks Randy That saved the day. It was one of those things that seem silly when you know but a real pain when nothing wants to work. The unit did come with some earlier DOS software and a while ago I booted up the Dolch luggable, that I keep for the Z3801A and SatStat, and ran the DOS GPS90 software but that was doing the same thing. My problem??? The VP comand set document doesn't mention, or not that I can see anyway, the need for that leading zero, so I was using @@Cg1.and it don't like that:-) Considering the antenna is only propped up on a ground floor window sill for now, and signal levels are on the low side, all is looking good, with a 10 degree mask angle it's seeing 10 or 11 satellites and so far tracking 3. It turns out to be an early 8 channel, a B3 model, but as long as it has the 1PPS output, that should be ok for what I need. Thanks too for the other information, I'll look out for a copy of TAC32 and try that later. regards and thanks again 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.
Re: [time-nuts] Oncore VP problem
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Nigel, You should be able to restart the VP with the @@Cg command in the "Additional Message Window" in WinOncore12. The total command string is: @@Cg01. Note that with the VP this must be done after every receiver default or SelfTest. Rick Hambly's SynTac/TAC32 software is smart enough that it does this automatically, but WinOncore12 was built after the VP's were pretty much gone. NOTE that WinOncore12 is pretty much useless if you are running a 6 channel receiver or an 8 channel VP in 6 channel mode as about the only 6 channel message it understands is the @@Bb satellite report. For this you need to use Rick's software or find an OLD DOS version of the Motorola software. You will also encounter trouble trying to run a lot of the more esoteric 8 channel messages that the VP supported. WinOncore12 has no idea about what to do with these. Once again, Rick's software will come to the rescue. Best regards, Randy Warner Senior Applications Engineer Geodetics, Inc. 858.729.0872 _ -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, July 17, 2007 12:34 PM To: time-nuts@febo.com Subject: [time-nuts] Oncore VP problem ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Hi All I'm trying to set up a supposedly NOS GPS development kit, similar to the old Motorola evalution kit, with an Oncore VP mounted on an interface board fitted with a 5 volt regulator and MAX232 interface chip. Running WinOncore12 under WinXP I can talk to the module ok, enter location info and get it to return it's ID etc, but other than that I can't get it to do anything. I've discovered from the VP command set that it goes into idle mode after a self test and needs a "position fix mode" command to put it back into "fix" mode. Unfortunately, although the module acknowledges the command it reports that it's still in idle mode. I'll dig out a DOS PC later, and try an earlier version of the software, but if anyone's come across this before I'd be grateful for any tips as to how I can kick it back into life again. 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 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] Exact Rubidium frequency
From: Peter Vince <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Exact Rubidium frequency Date: Tue, 17 Jul 2007 19:45:08 +0100 Message-ID: <[EMAIL PROTECTED]> > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] > > Hello Tom, > > I'd not had a reply from NIST, so was about to write to a > contact there. Have they just quietly done it, or did you nudge > someone? Anyway, yes, thank you, the table gives the 610.904 figure > from the French work, but the image still has the old 608 figure on > it:-( I had a reply from PTB who agreed their figure was out of date > and that 610.904 was the currently accepted figure, and promised to > update the web, but so far they haven't :-( > > Anyway, it's good to get to the bottom of the mystery - > thanks for your help. Now I'll just update Wikipedia! Well, what happend to 610.904324 then? It's on my page http://rubidium.dyndns.org/~magnus/physics/hyperfine/ The link I have to the article seems to have roten, but it should be possible to dig up it again. I have it somewhere in my files. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP-3336A - High Precision Attenuator
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] On Tue, 17 Jul 2007 08:42:56 -0700 (PDT), Tom Clifton <[EMAIL PROTECTED]> wrote: >Greg Burnett hit the nail on the head. It is a >machined base with four solenoids. I'm a bit hesitant >to start taking screws out of it as I'm not sure what >holds what together... Though if it is dead, what >additional harm can I do... > >Any waym the assembly seems to have an HP part number >of 1979a - anybody ahve a schematic on either the high >precision attenuator for the 3336a or something on the >HP part number 1979a? > >I have photo's I can email if it would help. > >Tom in St. Louis > Maybe I can help with a drawing I made, if it happens to be the same design. Some years ago, I crossed paths with an 8350 RF Synthesizer. The RF module in it had a problem with setting the output level consistently. Going up and down at some dB output boundary, sometimes the value was good and sometimes it was off. I opened the unit up, found the output attenuator, and was able to open that and clean it. Fixed the problem for at least the week I had it. I made a hand drawing of what was in there, thinking it may come up again. Posted here: ftp://ftp.sonic.net/pub/users/rexa/HP_atten/HP_attenuat.gif My notes on the drawing says it is similar to 8494/95/96 attenuators. These are small HP bench attenuators that can be either manual (knob), or electronic controlled. I have a manual version labeled 5086-7362. I can't remember; I may have opened it up first before I had the courage to try the one in the 8350 RF unit. The one shown/described has 3 sections. Sounds like one in your unit has 4 sections. Maybe the design is the same. The parts inside are small and delicate, but I don't remember any major danger of breaking things when I opened it. I don't think I did anything on the actuator side, though. As you can see from the drawing, there is a channel down the middle, the geometry of which, I'm sure, maintains the impedance. On one side of the channel, are 3 attenuator sections on substrates. On the other side are 3 gold plated straight trace sections. 3 metal spring sections are deflected to connect-in either the attenuator or the straight conductor. Each actuator (solenoid for electronic, or cam for manual) moves two pins to force adjacent ends of metal strips onto an attenuator. In the deactivated position, the pins are relaxed and the metal strips bend to the straight-through sections. I gently cleaned the spring contacts and connector portions of the attenuators and through-strips. Can't remember what I used as a cleaning tool, maybe small strips of paper, maybe toothpicks. I think I used a small amount of alcohol or acetone. So my assault on the guts of the attenuator turned out successful, but use this information at your own risk. Some testing first to decide which atten increment change is behaving badly might help focus on which switch connections may have problems. Hope it helps. -Rex ___ 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] Oncore VP problem
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Hi All I'm trying to set up a supposedly NOS GPS development kit, similar to the old Motorola evalution kit, with an Oncore VP mounted on an interface board fitted with a 5 volt regulator and MAX232 interface chip. Running WinOncore12 under WinXP I can talk to the module ok, enter location info and get it to return it's ID etc, but other than that I can't get it to do anything. I've discovered from the VP command set that it goes into idle mode after a self test and needs a "position fix mode" command to put it back into "fix" mode. Unfortunately, although the module acknowledges the command it reports that it's still in idle mode. I'll dig out a DOS PC later, and try an earlier version of the software, but if anyone's come across this before I'd be grateful for any tips as to how I can kick it back into life again. 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.
Re: [time-nuts] Exact Rubidium frequency
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Hello Tom, I'd not had a reply from NIST, so was about to write to a contact there. Have they just quietly done it, or did you nudge someone? Anyway, yes, thank you, the table gives the 610.904 figure from the French work, but the image still has the old 608 figure on it:-( I had a reply from PTB who agreed their figure was out of date and that 610.904 was the currently accepted figure, and promised to update the web, but so far they haven't :-( Anyway, it's good to get to the bottom of the mystery - thanks for your help. Now I'll just update Wikipedia! Peter >Hi Peter, > >Do you like the way the NIST page looks now? > >http://tf.nist.gov/general/enc-re.htm#resonancefrequency >http://tf.nist.gov/general/enc-re.htm#rubidiumoscillator > >/tvb >>> Thank you all for your replies. It still begs the question of why >>> NIST and PTB disagree by nearly 5 Hz on their web pages - I'll write >>> and ask them, and report back what they say. >>> >>> Regards, >>> >>> Peter Vince (G8ZZR, London) >> >> Peter, >> >> Yes, please send a note to NIST and have them update the >> Rb hyperfine frequency that appears in: >> http://tf.nist.gov/general/enc-re.htm#rubidiumoscillator >> >> My guess is the old ...608 number came from a 1959 paper: >> Hyperfine Transitions in Rubidium-87 Vapor >> http://tf.nist.gov/timefreq/general/pdf/1537.pdf >> >> I suggest for the purposes of their glossary, the new number >> doesn't have to be accurate to the micro-Hertz and probably >> doesn't need to be changed every time someone does a new >> experiment with Rb. >> >> NIST gives the defined value for Cesium: 9,192,631,770 Hz >> and a rounded value for Hydrogen: 1,420,405,752 Hz, so a >> value of 6,384,682,612 Hz might do. Not sure what to say >> about ...612.8 vs. ...610.904. Let NIST figure that one out. >> >> Either way, I don't have to change my cars ;-) >> http://www.leapsecond.com/pages/unix/ >> >> /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cs stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] From: "Richard \(Rick\) Karlquist" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Cs stability Date: Tue, 17 Jul 2007 09:52:22 -0700 Message-ID: <[EMAIL PROTECTED]> Rick, > In case anyone still doesn't know who I am, I need to > mention that I designed the RF electronics in the > 5071A in an earlier life, circa 1990. > > Now that we have that out of the way, I will agree > with Magnus that the cited paper is severely flawed. Good, then I am not the only one seeing that. I must admitt that I didn't give it a comprehensive readthrough asI was tired as hell when I looked at it, but I did not get the necessary ques as I browsed through it and even as I dipped into certain parts in detail it left me unsatisfied. > We don't know what models of cesium were used, and > the paper seems to assume that any deviations with > respect to GPS are due solely to the cesium standards. > We also don't know anything about the GPS equipment. > Citation [3] is a 5071A product note. I guess this > is thrown in to imply that one of the cesiums is a > 5071A; but we can't be sure. There is only an indirect reference to 5071A in a. > A statement is taken > out of context from this product note to the effect > that "some cesiums don't have an independent means > of frequency setting", which might lead the casual > observer to think that this refers to the 5071A. > Actually, the 5071A does have an independent means > of frequency setting, as opposed to older cesium > clocks where you had to vary the C-field to change > the frequency. For this and other reasons, I don't > put much stock in the paper. Do note that he in the introductionary part shows the factor deviation of 2.7E-13 and that he adjusted it manually twice which can be seen in the second Fig 1. "Unfortunately, many atomic oscillators lack the possibility of non-invasive frequency tuning [3]. Using digital correction, the frequency offset of 2.7 E-13 as delivered from factory is shown in Fig.l to be reducable below 1 E-14 with only two frequency corrections at 1800 and 4O00 hours from start-up, leaving some environmental factors plus a number of unpredictable timing discrepancies lasting 50-500 horn." He actually points out that the 5071A lacks that correction, so he agrees with you. This correction can be done by him as an initial post-processing step. We just don't know, again. A little sentense or two more on how that was made would have enlighen us further on that subject. But what Cesium he actually used is not known. > I hope this clears up any confusion about the 5071A, now > made by my good friends at Symmetricom. Many, many thanks for the write-up. I greatly enjoyed it! Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cs stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] In case anyone still doesn't know who I am, I need to mention that I designed the RF electronics in the 5071A in an earlier life, circa 1990. Now that we have that out of the way, I will agree with Magnus that the cited paper is severely flawed. We don't know what models of cesium were used, and the paper seems to assume that any deviations with respect to GPS are due solely to the cesium standards. We also don't know anything about the GPS equipment. Citation [3] is a 5071A product note. I guess this is thrown in to imply that one of the cesiums is a 5071A; but we can't be sure. A statement is taken out of context from this product note to the effect that "some cesiums don't have an independent means of frequency setting", which might lead the casual observer to think that this refers to the 5071A. Actually, the 5071A does have an independent means of frequency setting, as opposed to older cesium clocks where you had to vary the C-field to change the frequency. For this and other reasons, I don't put much stock in the paper. Having said that, let me speak about how we addressed some of these issues in the 5071A. First, the matter of temperature dependent phase shift. If you have a really good frequency standard, you have to start to worry about a temperature ramp resulting in a phase ramp. Of course, a phase ramp is a frequency step, by definition. The previous modele, the 5061B, like most cesium clocks, had an architecture where the crystal oscillator "flywheel" was connected to a splitter that drove a microwave frequency multiplier from 10 MHz to 9.2 GHz and also an isolation amplifier. Both of these were absolutely full of narrow band tuned circuits with substantial temperature coefficients. The combination of these "rubber bands" caused the 10 MHz at the output connector to be fairly loosely correlated (in terms of 5071A specifications) with the microwave signals sloshing around the Cs cavity. In the 5071A, I used a combination of a new architecture and better circuit design to drastically reduce the temperature coefficient of phase. You can read about this in my 1992 FCS paper (available at ieee.org or www.karlquist.com/FCS92.pdf). We measured the RF hardware by itself to determine its phase contribution to the overall 5071A. Our resident perfectionist, Len Cutler, insisted that all electronic error contributions be less than a part in 10^14, including this one. I can assure you that Len was a very happy camper with respect to the RF chain, and, if you knew Len, you know that is saying something. Shortly after the introduction of the 5071A, we had some colleagues at JPL perform environmental tests on an early 5071A. For the better part of a year, they ramped up and down the temperature, humidity, and pressure to see if they could measure these tempcos. By using correlative techniques, such as ramping the temperature on a daily basis and looking for a fourier peak at 1 day, they were able to establish a measurement floor of something like a part in 10^15. They were never able to see any correlation whatsoever of frequency to the environment for any of the variables. Regarding magnetic field sensitivity. The mu metal shields of the 5071A are so effective that it is not necessary to demagnetize them. Even Len Cutler didn't think so. A standing joke was the 5071A demagnetizer accessory that we were going to build "one of these days". I think we finally did build one for some customer who was even more of a perfectionist than Len. He didn't see any improvement from using it. Anyway, I take any statements about the earth's magnetic field affecting 5071A with a large grain of salt. AC magnetic fields like 50 Hz, or 60 Hz, are also not a concern. The frequencies used internally in the 5071A are carefully chosen to avoid any correlation with those power line frequencies. Magnetic fields even in the milliTesla range have absolutely no effect, let alone nanoTesla. Regarding vibration, acceleration, etc: earlier cesium beam tubes did have a problem with the beam wandering around when the clock was installed on a ship. In the 5071A, Len carefully devised a technique to prevent beam wander from having any effect on accuracy. Now if you tipped a 5071A upside down, the 10811 would experience a "2g turnover" frequency step. The control loop would respond to this within its time constant. So, admittedly, you might have a temporary frequency shift. However, there is no known application where a clock needs to work upside down, so even Len couldn't justify worrying about this. I hope this clears up any confusion about the 5071A, now made by my good friends at Symmetricom. Rick Karlquist N6RK (now with Agilent) These are my own opinions and don't represent HP, Agilent, or Symmetricom. > > > In the article "OBSERVATIONS ON STABILITY MEASUREMENTS > > > OF COMMERCIAL ATOMIC CLOCKS", Pekka Eskelinen claims to > I
[time-nuts] HP-3336A - High Precision Attenuator
Greg Burnett hit the nail on the head. It is a machined base with four solenoids. I'm a bit hesitant to start taking screws out of it as I'm not sure what holds what together... Though if it is dead, what additional harm can I do... Any waym the assembly seems to have an HP part number of 1979a - anybody ahve a schematic on either the high precision attenuator for the 3336a or something on the HP part number 1979a? I have photo's I can email if it would help. Tom in St. Louis Yahoo! oneSearch: Finally, mobile search that gives answers, not web links. http://mobile.yahoo.com/mobileweb/onesearch?refer=1ONXIC ___ 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 stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] In message: <[EMAIL PROTECTED]> "Tom Van Baak" <[EMAIL PROTECTED]> writes: : ); SAEximRunCond expanded to false : Errors-To: [EMAIL PROTECTED] : : > In the article "OBSERVATIONS ON STABILITY MEASUREMENTS : > OF COMMERCIAL ATOMIC CLOCKS", Pekka Eskelinen claims to : > have measured a phase temperature coefficient of 100ns/degree : > for commercial Cs clocks in 1999. : : Something is wrong with that claim. There's no way a modern : cesium standard exhibits a phase shift of 100 ns for a one : degree change in ambient temperature. I have Cs standards : that often change in temperature by several degrees and still : keep to nanoseconds. I guess I need to decode that paper : and see what's wrong. Does anyone have contact with the : authors (Finland)? We have HP5071A's that keep to about 5ns over the course of a typical heading/cooling cycle measured relative to GPS. This is over a range of maybe 15C in the summer... Warner ___ 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 stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] From: Dr Bruce Griffiths <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Cs stability Date: Tue, 17 Jul 2007 21:30:03 +1200 Message-ID: <[EMAIL PROTECTED]> > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] > > Tom Van Baak wrote: > >> I guess that is why some GPS antenna cables is temperature-stabilized as > >> well > >> as the cement-pidestal for the GPS antenna as it stands on solid rock. The > >> same > >> place have controlled environment for the cesiums and hydrogens, together > >> with > >> UPS and disel-engine that kicks in for longer runs. > >> > >> Or I could be wrong... :) > >> > > > > Magnus, > > > > This is true (temperature stabilization) for sites that do mm > > level survey and ps level time transfer, using all the tricks > > in the GPS book. > > > > On the other hand, I think for most of us that play at the > > meter and ns levels with cheap OEM receivers and plastic > > L1 antennas the coax cable temperature issue is quite > > overblown. Or if I'm wrong, show me the data. > > > > /tvb > > > > > > > Tom > > Calculations are easy: > > Cable delay tempco is at worst 100ppm/K. > with 100ns of cable delay tempco will be 10ps?K or less. > With a 20K temperature change change in delay will be 200ps or less. > The group delay tempco of the antenna components (bandpass filters > amplifiers etc ) is likely to be much greater. Tom's point is that while we are toying around with L1 C/A code-tracking receivers the effective noise is so large that more finegrained compensations in the GPS solution is note taken out so other finegrained offsets will also be lost. I agree with him. When you toy with dual frequency carrier-tracking receivers you gain a much better precision in ionspheric correction. Operating in mm or sub-mm RMS noise on pseudo-ranges noise sources as change of temperature in cables and mountning stands certainly comes in, as well as the phase stability of the antenna, quality sites compensates for antenna phase deviation as they change over the satelite coarse. But that's not very meaningfull for a L1 C/A code-tracking only receiver, infact such efforts are lost in the noise and uncompensated biases you have. Especially considering a cheezy TCXO. So while it is easy to calculate and compensate, the meaningfullness depends on the situation. Compensating for cable delay may however be worth it. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cs stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] I guess I'm a bit out of date! :-) Rob -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Björn Gabrielsson Sent: 17 July 2007 14:13 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Cs stability ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] "Achieved: Acceleration sensitivities better than 2E-12/g" http://www.zyfer.com/briefings/telecom/qz%20low-g%20brfg%20olie%204-04.pdf -- Björn On Tue, July 17, 2007 14:40, Rob Kimberley said: > Another way that has been incorporated successfully to combat g > sensitivity are accelerometers mounted on each of the x, y, Z axes of > the crystal. > Combining this with spring mounts works well. g sensitivities down to > e-10 per g can be achieved. > > Rob K > > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf Of [EMAIL PROTECTED] > Sent: 17 July 2007 06:14 > To: time-nuts@febo.com > Subject: Re: [time-nuts] Cs stability > > ); SAEximRunCond expanded to false > Errors-To: > time-nuts-bounces+rk=timing-consultants.com+rk=timing-consultants.com@ > time-nuts-bounces+febo.c > om > > > In a message dated 7/16/2007 12:10:54 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > >>For example tilting the Cs unit by 90 degrees will typically give an >>error > >>of about 1E-09 or so. > >>It would take some time for the control loops to compensate for this > error. > > > > Hi guys, > > I did tilt my 4050 when I first installed the unit, that number is > from my memory. Notice that Magnus is right of course, the Cs will > compensate the tilt, given enough time to do so. I did not mean that > the 1E-09 error will stay permanent of course, as I said in the > follow-on sentence. > > Also the 4050 is not very well temperature compensated compared to > modern units, I was not impressed when I saw the FTS tempco > specifications. A good GPSDO can outperform the 4050. > > I have a military OCXO sample (new product) that is supposed to be > "g-insensitive" and even that one has about E-09 frequency shift per > 90 degrees tilt. > > One of the only ways to get around that is to use three crystals in > series, with the three crystals oriented in the the XYZ axis, so their > errors compensate out. > > Vibration is also a big enemy of crystal oscillators of course. > > bye, > Said > > > > ** Get a sneak peek of the all-new > AOL at http://discover.aol.com/memed/aolcom30tour > ___ > 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] Cs stability
"Achieved: Acceleration sensitivities better than 2E-12/g" http://www.zyfer.com/briefings/telecom/qz%20low-g%20brfg%20olie%204-04.pdf -- Björn On Tue, July 17, 2007 14:40, Rob Kimberley said: > Another way that has been incorporated successfully to combat g > sensitivity > are accelerometers mounted on each of the x, y, Z axes of the crystal. > Combining this with spring mounts works well. g sensitivities down to e-10 > per g can be achieved. > > Rob K > > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of [EMAIL PROTECTED] > Sent: 17 July 2007 06:14 > To: time-nuts@febo.com > Subject: Re: [time-nuts] Cs stability > > ); SAEximRunCond expanded to false > Errors-To: > [EMAIL PROTECTED] > om > > > In a message dated 7/16/2007 12:10:54 Pacific Daylight Time, > [EMAIL PROTECTED] writes: > >>For example tilting the Cs unit by 90 degrees will typically give an >>error > >>of about 1E-09 or so. > >>It would take some time for the control loops to compensate for this > error. > > > > Hi guys, > > I did tilt my 4050 when I first installed the unit, that number is from my > memory. Notice that Magnus is right of course, the Cs will compensate the > tilt, given enough time to do so. I did not mean that the 1E-09 error > will > stay permanent of course, as I said in the follow-on sentence. > > Also the 4050 is not very well temperature compensated compared to modern > units, I was not impressed when I saw the FTS tempco specifications. A > good > GPSDO can outperform the 4050. > > I have a military OCXO sample (new product) that is supposed to be > "g-insensitive" and even that one has about E-09 frequency shift per 90 > degrees tilt. > > One of the only ways to get around that is to use three crystals in > series, > with the three crystals oriented in the the XYZ axis, so their errors > compensate out. > > Vibration is also a big enemy of crystal oscillators of course. > > bye, > Said > > > > ** Get a sneak peek of the all-new AOL > at http://discover.aol.com/memed/aolcom30tour > ___ > 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] Cs stability
Another way that has been incorporated successfully to combat g sensitivity are accelerometers mounted on each of the x, y, Z axes of the crystal. Combining this with spring mounts works well. g sensitivities down to e-10 per g can be achieved. Rob K -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: 17 July 2007 06:14 To: time-nuts@febo.com Subject: Re: [time-nuts] Cs stability ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] om In a message dated 7/16/2007 12:10:54 Pacific Daylight Time, [EMAIL PROTECTED] writes: >For example tilting the Cs unit by 90 degrees will typically give an >error >of about 1E-09 or so. >It would take some time for the control loops to compensate for this error. Hi guys, I did tilt my 4050 when I first installed the unit, that number is from my memory. Notice that Magnus is right of course, the Cs will compensate the tilt, given enough time to do so. I did not mean that the 1E-09 error will stay permanent of course, as I said in the follow-on sentence. Also the 4050 is not very well temperature compensated compared to modern units, I was not impressed when I saw the FTS tempco specifications. A good GPSDO can outperform the 4050. I have a military OCXO sample (new product) that is supposed to be "g-insensitive" and even that one has about E-09 frequency shift per 90 degrees tilt. One of the only ways to get around that is to use three crystals in series, with the three crystals oriented in the the XYZ axis, so their errors compensate out. Vibration is also a big enemy of crystal oscillators of course. bye, Said ** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour ___ 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 stability
Or see a failed TIC test which actually displayed the delay in a piece of coax showing the temperature in the room as the air conditioning was turning on and off over night. http://www.ko4bb.com/Test_Equipment/data/HP5370A coax cable delay.png I did not calibrate this thermometer though :-) Didier KO4BB -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Van Baak Sent: Monday, July 16, 2007 9:47 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Cs stability > Who was it that said; every clock is a thermometer? Even a short length of coax is a thermometer if you look close enough. See the 50 fs / °C tempco at test #6: http://www.leapsecond.com/pages/tadd-1/ /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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-3336A Manual
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Dear Tom, Greg, other Time-nuts, I was triggered by the story of Greg about the high precision attenuators. Lately I bought a bunch of Agilent high precision attenuators. These have Agilent/HP part numbers 3332x-x (x denotes various numbers). These units were bought cheap, so .. defective. I'm still working on them, but I can manage to end up with 2 or 3 working attenuators. If you are going to work on them, all you need is a small hex-key. But beware: These units are made in a very inventive professional way. Don't get tempted to remove the solenoids from the "main-frame" without detaching the bottom-side (were the RF-connectors are). First remove the bottom-side and by carefully bending remove the plungers from the RF-tongues. By not doing so, the tongues can be damaged. A damaged tongue is impossible to repair, as it is very thin copper(?) which is glued in place on an insulator. Tip: Check the small O-rings which are used as dampers for the plungers. You can see them at the place were the plungers are connected to the moveable parts of the solenoids. There should be two at each plunger, one for the push, the other one for the pull action. Good luck! 73 Jeroen PE1RGE Greg Burnett wrote: >); SAEximRunCond expanded to false >Errors-To: [EMAIL PROTECTED] > >Tom, > >I was last involved with a 3336A about 12 years ago, so I hope I can still >remember the correct situation (but no guarantee). > >As I remember it, there are some relays in that aluminum box between the >circuit board and the front panel 75, 135 and 600 ohm outputs. If you have >the older, tall, yellow plastic relays in there, then those relays might be >your problem -- they were not reliable over time. But if you have the newer, >black low-profile Omron relays, then you've got good relays (that are far >less likely to fail). > >Given your symptom, I'd guess you have the older, tall, yellow plastic >relays. If I remember correctly, that version relay clips to the PCB and its >gold leaf contacts actually touch pads on the PCB -- so the PCB itself >becomes part of the relay action. The newer, black Omron relays are potted, >completely self-contained, and are soldered into a re-designed board. > >BTW, if your unit has the option 005 precision attenuator, then the >precision attenuator is an aluminum cast base, with solenoids on top (and a >removeable cover for access to the solenoids) and a factory-only-repairable >main channel milled-into the aluminum base, with the attenuator pads in the >form of laser-etched substrate pads that fit into the channel. ...The >solenoids push various gold-plated leaf contacts against the small contact >pads on the substrate pads. > >Best, >Greg > > > >- Original Message - >From: "Tom Clifton" <[EMAIL PROTECTED]> >To: >Sent: Monday, July 16, 2007 1:16 PM >Subject: [time-nuts] HP-3336A Manual > > >I perused the pdf manual and came up more confused >than when I started... > >My problem seems to be in the Option 005 high >precision attenuator (as I can best tell). There is >an aluminum box between the circuit board and the >front panel 75 ohm, 135 ohm and 600 ohm outputs. That >mysterious 'box' seems to be open. I'm not sure if >it is just an impedence matching assembly, or if it >includes the option 005. > >As the front panel level control is changed, the raw >50 ohm board output measures between +5 and -5 dbm and >every time the display crosses a -3dbm threshold (-3, >-13, -23 etc) you hear a relay click and the raw >output jumps back up 10db. > >Hope that clarifies more than confuses... > > > > > >___ >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. > > > > > -- Ing. Jeroen Bastemeijer Delft University of Technology Department of Electrical Engineering Electronic Instrumentation Laboratory Mekelweg 4, Room 13.090 2628 CD Delft The Netherlands Phone: +31.15.27.86542 Fax: +31.15.27.85755 E-mail: [EMAIL PROTECTED] GPS: Lat N52.2 Lon E4.37157 Alt 46.2m ___ 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 stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Tom Van Baak wrote: >> I guess that is why some GPS antenna cables is temperature-stabilized as well >> as the cement-pidestal for the GPS antenna as it stands on solid rock. The >> same >> place have controlled environment for the cesiums and hydrogens, together >> with >> UPS and disel-engine that kicks in for longer runs. >> >> Or I could be wrong... :) >> > > Magnus, > > This is true (temperature stabilization) for sites that do mm > level survey and ps level time transfer, using all the tricks > in the GPS book. > > On the other hand, I think for most of us that play at the > meter and ns levels with cheap OEM receivers and plastic > L1 antennas the coax cable temperature issue is quite > overblown. Or if I'm wrong, show me the data. > > /tvb > > > Tom Calculations are easy: Cable delay tempco is at worst 100ppm/K. with 100ns of cable delay tempco will be 10ps?K or less. With a 20K temperature change change in delay will be 200ps or less. The group delay tempco of the antenna components (bandpass filters amplifiers etc ) is likely to be much greater. 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] Cs stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Tom Van Baak wrote: >> Yes it can make sense. >> Place one Cs clock in a chamber where the ambient temperature can be >> adjusted to various fixed temperatures. Compare the phase of its >> 5/10MHz and/or PPS outputs with respect to those of another Cs standard >> held at constant temperature. >> > > Bruce, > > I'm not sure I follow this. Yes, you will see a phase shift but > how can you tell how much of said shift is due to a fixed > phase shift (as if it were cable phase tempco) vs. how much > is due to phase shift due to frequency offset (as if it were > oscillator frequency tempco)? No change in temperature is > instantaneous; during the (slow) change both phase and > frequency (equals phase change over time) may change. > > /tvb > > Tom The cable phase shift can be compensated by having the interconnect cable experience the same environment for equivalent lengths. If the temperature is ramped slowly enough the uncorrected frequency excursions will be relatively small, otherwise the phase shift due to the integral of the frequency excursion over time may well be significant. My point was that Cs standard only regulates (in the long term) the frequency or rate of change of phase and not the initial phase which is essentially arbitrary and may well have a significant tempco due to the tempcos of the synthesiser delay and any buffer delay. The control loop endeavours to control the frequency experienced by the Cs beam which is subject to delays in the synthesis chain so that the phase at the crystal oscillator output itself will be dependent on these temperature dependent delays. 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] Exact Rubidium frequency
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Hi Peter, Do you like the way the NIST page looks now? http://tf.nist.gov/general/enc-re.htm#resonancefrequency http://tf.nist.gov/general/enc-re.htm#rubidiumoscillator /tvb >> Thank you all for your replies. It still begs the question of why >> NIST and PTB disagree by nearly 5 Hz on their web pages - I'll write >> and ask them, and report back what they say. >> >> Regards, >> >> Peter Vince (G8ZZR, London) > > Peter, > > Yes, please send a note to NIST and have them update the > Rb hyperfine frequency that appears in: > http://tf.nist.gov/general/enc-re.htm#rubidiumoscillator > > My guess is the old ...608 number came from a 1959 paper: > Hyperfine Transitions in Rubidium-87 Vapor > http://tf.nist.gov/timefreq/general/pdf/1537.pdf > > I suggest for the purposes of their glossary, the new number > doesn't have to be accurate to the micro-Hertz and probably > doesn't need to be changed every time someone does a new > experiment with Rb. > > NIST gives the defined value for Cesium: 9,192,631,770 Hz > and a rounded value for Hydrogen: 1,420,405,752 Hz, so a > value of 6,384,682,612 Hz might do. Not sure what to say > about ...612.8 vs. ...610.904. Let NIST figure that one out. > > Either way, I don't have to change my cars ;-) > http://www.leapsecond.com/pages/unix/ > > /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cs stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] > I'm not sure I follow this. Yes, you will see a phase shift but how > can you tell how much of said shift is due to a fixed phase shift (as > if it were cable phase tempco) vs. how much is due to phase shift due > to frequency offset (as if it were oscillator frequency tempco)? No > change in temperature is instantaneous; during the (slow) change both > phase and frequency (equals phase change over time) may change. Measure the phase. Change the temperature. Wait and watch. If the new phase is stable/constant, you have a phase shift. If it grows linear with time you have a frequency shift. -- 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.
Re: [time-nuts] Cs stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] From: "Tom Van Baak" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Cs stability Date: Tue, 17 Jul 2007 00:40:49 -0700 Message-ID: <[EMAIL PROTECTED]> > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] > > > In the article "OBSERVATIONS ON STABILITY MEASUREMENTS > > OF COMMERCIAL ATOMIC CLOCKS", Pekka Eskelinen claims to > > have measured a phase temperature coefficient of 100ns/degree > > for commercial Cs clocks in 1999. > > Something is wrong with that claim. There's no way a modern > cesium standard exhibits a phase shift of 100 ns for a one > degree change in ambient temperature. I have Cs standards > that often change in temperature by several degrees and still > keep to nanoseconds. I guess I need to decode that paper > and see what's wrong. I think the paper lacks a number of necessary details in order to fully understand the conditions under which this exercise took place. There is no clear list of equipment used. It can be implied that it is 5071A being used. What Time Interval counters where used is for instance not known. He have compared PPS outputs between GPS receivers (which model are those?) and Cesium. I'd like to see some investigations into how stable the GPSes and measurement equipment is to temperature. In the end, there are a few pages of material missing in there for it to give a fairly comprehensive picture. Many of these issues could probably be cleared up after some discussions with the author, but we should not have to rely on side- channels like that. It's an interesting article, but it leaves me with a few questionsmarks. It is a bit unsatisfying. > Does anyone have contact with the authors (Finland)? Should not be too hard as his email adderess is at the top of the first page. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cs stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] From: "Tom Van Baak" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Cs stability Date: Tue, 17 Jul 2007 00:21:37 -0700 Message-ID: <[EMAIL PROTECTED]> > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] > > > I guess that is why some GPS antenna cables is temperature-stabilized as > > well > > as the cement-pidestal for the GPS antenna as it stands on solid rock. The > > same > > place have controlled environment for the cesiums and hydrogens, together > > with > > UPS and disel-engine that kicks in for longer runs. > > > > Or I could be wrong... :) > > Magnus, Tom, > This is true (temperature stabilization) for sites that do mm > level survey and ps level time transfer, using all the tricks > in the GPS book. > > On the other hand, I think for most of us that play at the > meter and ns levels with cheap OEM receivers and plastic > L1 antennas the coax cable temperature issue is quite > overblown. Or if I'm wrong, show me the data. I never claimed otherwise. I mearly pointed out that _some_ antennas have that arrangement among a number of others. Clearly few of us happy amatuers play in that league. Some of us have GPS receivers and antennas at that level. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cs stability
> In the article "OBSERVATIONS ON STABILITY MEASUREMENTS > OF COMMERCIAL ATOMIC CLOCKS", Pekka Eskelinen claims to > have measured a phase temperature coefficient of 100ns/degree > for commercial Cs clocks in 1999. Something is wrong with that claim. There's no way a modern cesium standard exhibits a phase shift of 100 ns for a one degree change in ambient temperature. I have Cs standards that often change in temperature by several degrees and still keep to nanoseconds. I guess I need to decode that paper and see what's wrong. Does anyone have contact with the authors (Finland)? /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cs stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] > Yes it can make sense. > Place one Cs clock in a chamber where the ambient temperature can be > adjusted to various fixed temperatures. Compare the phase of its > 5/10MHz and/or PPS outputs with respect to those of another Cs standard > held at constant temperature. Bruce, I'm not sure I follow this. Yes, you will see a phase shift but how can you tell how much of said shift is due to a fixed phase shift (as if it were cable phase tempco) vs. how much is due to phase shift due to frequency offset (as if it were oscillator frequency tempco)? No change in temperature is instantaneous; during the (slow) change both phase and frequency (equals phase change over time) may change. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cs stability
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] > I guess that is why some GPS antenna cables is temperature-stabilized as well > as the cement-pidestal for the GPS antenna as it stands on solid rock. The > same > place have controlled environment for the cesiums and hydrogens, together with > UPS and disel-engine that kicks in for longer runs. > > Or I could be wrong... :) Magnus, This is true (temperature stabilization) for sites that do mm level survey and ps level time transfer, using all the tricks in the GPS book. On the other hand, I think for most of us that play at the meter and ns levels with cheap OEM receivers and plastic L1 antennas the coax cable temperature issue is quite overblown. Or if I'm wrong, show me the data. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cs stability
In a message dated 7/16/2007 22:26:14 Pacific Daylight Time, [EMAIL PROTECTED] writes: > I have a military OCXO sample (new product) that is supposed to be > "g-insensitive" and even that one has about E-09 frequency shift per 90 degrees tilt. >... and you have not put a GPS diciplining on it yeat??? Of course we did :) But it still takes some time for the loop to fix the error. We will address that in a next generation mobile product... bye, Said ** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour ___ 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.
