Re: [time-nuts] Frequency comparison
Bob, You are right, I am using an analog multi-meter where its easy to observe the needle movement. At 08-02-10, you wrote: >Hi > >If you mix the RB and GPS down with a mixer you eventually will run into a >problem. > >As you set them both very close to frequency, the output is a noisy DC >signal rather than a sine wave. Since each source can drift either up or >down for a short period of time, it can be hard to tell what's going on with >a zero crossing detector. It is much better to capture the output voltage >with a strip chart or the digital equivalent. > >Bob -- Raj, VU2ZAP Bangalore, India. ___ 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] True to there word.
Concerning WWVB from someone that used it way back to check my reference for a few years before I had GPS. Short conclusion, with what I was doing and the equipment I had (a WWVB receiver Tracor 599), Its Ok to about 1 part in 1e9 for most of the day and with luck and care on a good day, to a few parts in e10. It was pretty useless at night, hard to keep track of what cycle it was on, too much jumping around and time shift drift. It was completely useless at the diurnal shift, It went to zero for a few minutes, lost sync and then came back with a new random sync on the 60 KHz phase and the 100KHz reference Freq. During the winter season it made a better weather station than a Freq standard, with the day time fluxuations being more a function of the weather between Calif and Colorado than of my Osc. It was OK in the summer, but I could still use it to predict bad weather in-between me and the transmitter. Don't think you would NEVER ever want to lock on to it for a WWVB-DO, It is just used to watch for phase drift during the lucky part of the day. Oh, I don't miss them good ol days. ws ** Hi My assumption is that that the same propagation effects that move the phase also delay the arrival of the modulation. The ID on WWVB is a 45 degree (?) >carrier phase shift. At the very least, I think you would need to let the loop know about that. I do hardware one week and software the next. Right now I'm writing a bunch of Perl Bob * On Feb 8, 2010, at 8:51 PM, Bob Paddock wrote: On Mon, Feb 8, 2010 at 8:40 PM, Bob Camp wrote: I assume that you are going to have to train your loop to "expect" the ID shifts and time markers. Again, they are predictable. Would it not be easier to use the WWVB Zero-Crossings to sync something? Then the power shifts should not mater. It's just software You must be a hardware person... :-) Yes, but WWVB is a PITA to use (because of the diurnal shifts) compared to LORAN. -John === Hi WWVB is pretty safe. When they do a cost/benefit thing on these services, they take a look at how many taxpayers are using the service as intended. The "mission" of WWWVB is to put out time signals. There are a *lot* of taxpayers with WWVB "atomic clocks" on their walls. Bob -Original Message- Subject: [time-nuts] True to there word. The lights went out (actually red) on my Austron 2100 r this morning. (whats next WWVB ?) Don H ___ 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] True to there word. - Fancy WWVB
Hi My assumption is that that the same propagation effects that move the phase also delay the arrival of the modulation. The ID on WWVB is a 45 degree (?) carrier phase shift. At the very least, I think you would need to let the loop know about that. I do hardware one week and software the next. Right now I'm writing a bunch of Perl Bob On Feb 8, 2010, at 8:51 PM, Bob Paddock wrote: > On Mon, Feb 8, 2010 at 8:40 PM, Bob Camp wrote: > >> I assume that you are going to have to train your loop to "expect" the ID >> shifts and time >> markers. Again, they are predictable. > > Would it not be easier to use the WWVB Zero-Crossings to sync something? > Then the power shifts should not mater. > >> It's just software > > You must be a hardware person... :-) > > > > -- > http://www.wearablesmartsensors.com/ > http://www.softwaresafety.net/ > http://www.designer-iii.com/ > http://www.unusualresearch.com/ > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts 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] True to there word. - Fancy WWVB
Hi I suspect there is more to the compensation process than just time of day. At some point it would get a bit crazy to collect all the data. It would be interesting to look into though. I'm by no means suggesting that WWVB would replace Loran. My *guess* is that it would be competitive with skywave Loran-C. I've locked an Austron 2100 to the European chains. It can indeed be done. The only real issue is how good the result is (or isn't). Bob On Feb 8, 2010, at 8:49 PM, J. Forster wrote: > I was using a HP 105B and 117A before the Austron 2100F and still have > them. From what I remember, the diurnal shift was not repeatable. > > By looking at an output from the 117A and syncing the 'scope to the 105B, > I could assess the quality of the signal pretty well. Sometimes it was > stable, sometimes it was jittering all over the place by a cycle or more. > > Bottom line is, IMO, WWVB is no substitute for LORAN. > > I'm still hoping that the european chains will be usable. > > YMMV, > > -John > > > > >> Hi >> >> Yes indeed, you need to be sure you don't get a cycle slip. That's not >> trivial when the signal goes to zero while moving phase. >> >> There I think you need to depend on something like a reasonable OCXO and a >> long time constant loop. That brings in other problems. I assume that you >> are going to have to train your loop to "expect" the ID shifts and time >> markers. Again, they are predictable. It's just software >> >> More or less: >> >> Take all of the things you can compute about the signal and feed them in. >> Lock the "computed" signal against the received signal. Way less complex >> than what they do with GPS. Since it's all *very* slow, a beater PC can >> easily keep up with all the adjustment math. >> >> Bob >> >> >> On Feb 8, 2010, at 8:28 PM, J. Forster wrote: >> >>> If you track for a day, and draw a straight line throught the diurnal >>> shift, you can easily see a frequency drift of 45 degrees. That's 1/8 >>> cycle of 60 KHz or about 2 uS. So 2x 10 E-6 out of 10 E5, so you can see >>> 2 >>> x 10 E-11 in a day. >>> >>> ASSUMING the lock does not break. >>> >>> -John >>> >>> === >>> >>> >>> Hi People rarely want to use WWVB mobile. The location of the transmitter and receiver can be looked up on a map. The time of sunrise at both locations should be something that could be calculated. Assuming you are willing to put up with all of that, you should be able to do a first order correction on the shifts. The question obviously is - just how good would the net result be? Is it a 5:1 sort of thing or do you get a couple of orders of magnitude? Bob On Feb 8, 2010, at 6:40 PM, J. Forster wrote: > Yes, but WWVB is a PITA to use (because of the diurnal shifts) > compared > to > LORAN. > > -John > > === > > >> Hi >> >> WWVB is pretty safe. When they do a cost/benefit thing on these >> services, >> they take a look at how many taxpayers are using the service as >> intended. >> The "mission" of WWWVB is to put out time signals. There are a *lot* >> of >> taxpayers with WWVB "atomic clocks" on their walls. >> >> Bob >> >> -Original Message- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] >> On >> Behalf Of Don Henderickx >> Sent: Monday, February 08, 2010 4:07 PM >> To: Discussion of precise time and frequency measurement >> Subject: [time-nuts] True to there word. >> >> The lights went out (actually red) on my Austron 2100 r this morning. >> (whats next WWVB ?) >> Don H >> >> ___ >> 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. >>> >>> >>> >>> ___ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>>
Re: [time-nuts] True to there word. - Fancy WWVB
I was using a HP 105B and 117A before the Austron 2100F and still have them. From what I remember, the diurnal shift was not repeatable. By looking at an output from the 117A and syncing the 'scope to the 105B, I could assess the quality of the signal pretty well. Sometimes it was stable, sometimes it was jittering all over the place by a cycle or more. Bottom line is, IMO, WWVB is no substitute for LORAN. I'm still hoping that the european chains will be usable. YMMV, -John > Hi > > Yes indeed, you need to be sure you don't get a cycle slip. That's not > trivial when the signal goes to zero while moving phase. > > There I think you need to depend on something like a reasonable OCXO and a > long time constant loop. That brings in other problems. I assume that you > are going to have to train your loop to "expect" the ID shifts and time > markers. Again, they are predictable. It's just software > > More or less: > > Take all of the things you can compute about the signal and feed them in. > Lock the "computed" signal against the received signal. Way less complex > than what they do with GPS. Since it's all *very* slow, a beater PC can > easily keep up with all the adjustment math. > > Bob > > > On Feb 8, 2010, at 8:28 PM, J. Forster wrote: > >> If you track for a day, and draw a straight line throught the diurnal >> shift, you can easily see a frequency drift of 45 degrees. That's 1/8 >> cycle of 60 KHz or about 2 uS. So 2x 10 E-6 out of 10 E5, so you can see >> 2 >> x 10 E-11 in a day. >> >> ASSUMING the lock does not break. >> >> -John >> >> === >> >> >> >>> Hi >>> >>> People rarely want to use WWVB mobile. The location of the transmitter >>> and >>> receiver can be looked up on a map. The time of sunrise at both >>> locations >>> should be something that could be calculated. >>> >>> Assuming you are willing to put up with all of that, you should be able >>> to >>> do a first order correction on the shifts. The question obviously is - >>> just how good would the net result be? Is it a 5:1 sort of thing or do >>> you >>> get a couple of orders of magnitude? >>> >>> Bob >>> >>> On Feb 8, 2010, at 6:40 PM, J. Forster wrote: >>> Yes, but WWVB is a PITA to use (because of the diurnal shifts) compared to LORAN. -John === > Hi > > WWVB is pretty safe. When they do a cost/benefit thing on these > services, > they take a look at how many taxpayers are using the service as > intended. > The "mission" of WWWVB is to put out time signals. There are a *lot* > of > taxpayers with WWVB "atomic clocks" on their walls. > > Bob > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] > On > Behalf Of Don Henderickx > Sent: Monday, February 08, 2010 4:07 PM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] True to there word. > > The lights went out (actually red) on my Austron 2100 r this morning. > (whats next WWVB ?) > Don H > > ___ > 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. >>> >>> >> >> >> >> ___ >> 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] True to there word. - Fancy WWVB
On Mon, Feb 8, 2010 at 8:40 PM, Bob Camp wrote: > I assume that you are going to have to train your loop to "expect" the ID > shifts and time > markers. Again, they are predictable. Would it not be easier to use the WWVB Zero-Crossings to sync something? Then the power shifts should not mater. > It's just software You must be a hardware person... :-) -- http://www.wearablesmartsensors.com/ http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] True to there word. - Fancy WWVB
Hi Yes indeed, you need to be sure you don't get a cycle slip. That's not trivial when the signal goes to zero while moving phase. There I think you need to depend on something like a reasonable OCXO and a long time constant loop. That brings in other problems. I assume that you are going to have to train your loop to "expect" the ID shifts and time markers. Again, they are predictable. It's just software More or less: Take all of the things you can compute about the signal and feed them in. Lock the "computed" signal against the received signal. Way less complex than what they do with GPS. Since it's all *very* slow, a beater PC can easily keep up with all the adjustment math. Bob On Feb 8, 2010, at 8:28 PM, J. Forster wrote: > If you track for a day, and draw a straight line throught the diurnal > shift, you can easily see a frequency drift of 45 degrees. That's 1/8 > cycle of 60 KHz or about 2 uS. So 2x 10 E-6 out of 10 E5, so you can see 2 > x 10 E-11 in a day. > > ASSUMING the lock does not break. > > -John > > === > > > >> Hi >> >> People rarely want to use WWVB mobile. The location of the transmitter and >> receiver can be looked up on a map. The time of sunrise at both locations >> should be something that could be calculated. >> >> Assuming you are willing to put up with all of that, you should be able to >> do a first order correction on the shifts. The question obviously is - >> just how good would the net result be? Is it a 5:1 sort of thing or do you >> get a couple of orders of magnitude? >> >> Bob >> >> On Feb 8, 2010, at 6:40 PM, J. Forster wrote: >> >>> Yes, but WWVB is a PITA to use (because of the diurnal shifts) compared >>> to >>> LORAN. >>> >>> -John >>> >>> === >>> >>> Hi WWVB is pretty safe. When they do a cost/benefit thing on these services, they take a look at how many taxpayers are using the service as intended. The "mission" of WWWVB is to put out time signals. There are a *lot* of taxpayers with WWVB "atomic clocks" on their walls. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Don Henderickx Sent: Monday, February 08, 2010 4:07 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] True to there word. The lights went out (actually red) on my Austron 2100 r this morning. (whats next WWVB ?) Don H ___ 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. >> >> > > > > ___ > 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] Frequency comparison - LPRO
Hi There's a multi turn pot and reference built into the LPRO. It's already driving the C field tuning. I assume you are leaving it in there. You should be able to get the unit to less than 5x10^-11 without a lot of crazy effort. With any luck, the LPRO TC plus a few months drift should be sub 1x10^-10. Net, you need 2x10^-10 or so of tuning range with a ~ monthly touch up. The normal tuning sensitivity is obviously much to large (10X) for this. The answer is actually fairly simple. Just put a nice big resistor in series with the electronic tune pin. No extra pots, references or other sources of added error. Just make sure the resistor has fairly good TC and you should be ok. Bob On Feb 8, 2010, at 6:29 PM, Neville Michie wrote: > > Hi, > I am setting up an LPRO in a steel box (for a little additional magnetic > shielding). > The power supply is a linear in a separate box (separate the magnetic fields). > In the LPRO box is a 5V voltage reference (2 x LT1009) which is used across a > pair of trim pots (coarse and fine) with two front panel jacks for a high > impedance > DVM to set the frequency trim voltage f the LPRO. > The LPRO is insulated with more than an inch of foam plastic and a small fan > (on the outside of the box) is used to control the 1/2 inch aluminium plate > that the > LPRO is bolted to to about 38*C. The temperature control is much better than > 1/10 degree. > Inside the box is a decimal divider with outputs down to 1Hz, and a phase > detector > composed of 2 D latches (CMOS) the output of which is filtered and fed to a > strip > chart recorder or data logger. > I have a TBOLT connected to a decimal divider, so I can compare the phase > with the LPRO. > At 10kHz I get 1microsecond per month resolution ~ 2x10^12. As errors show up > the trim voltage can be adjusted with the DVM by an amount that is easy to > calculate. > So with a bit of time and without much in the way of high precision timing > gear I hope > to be able to get the LPRO adjusted to the limits of its precision, and I > avoid the short term > fluctuations in the TBOLT output. > After a year or so I will be able to tell you how well it works. > > cheers, Neville Michie > > ___ > 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] True to there word. - Fancy WWVB
If you track for a day, and draw a straight line throught the diurnal shift, you can easily see a frequency drift of 45 degrees. That's 1/8 cycle of 60 KHz or about 2 uS. So 2x 10 E-6 out of 10 E5, so you can see 2 x 10 E-11 in a day. ASSUMING the lock does not break. -John === > Hi > > People rarely want to use WWVB mobile. The location of the transmitter and > receiver can be looked up on a map. The time of sunrise at both locations > should be something that could be calculated. > > Assuming you are willing to put up with all of that, you should be able to > do a first order correction on the shifts. The question obviously is - > just how good would the net result be? Is it a 5:1 sort of thing or do you > get a couple of orders of magnitude? > > Bob > > On Feb 8, 2010, at 6:40 PM, J. Forster wrote: > >> Yes, but WWVB is a PITA to use (because of the diurnal shifts) compared >> to >> LORAN. >> >> -John >> >> === >> >> >>> Hi >>> >>> WWVB is pretty safe. When they do a cost/benefit thing on these >>> services, >>> they take a look at how many taxpayers are using the service as >>> intended. >>> The "mission" of WWWVB is to put out time signals. There are a *lot* of >>> taxpayers with WWVB "atomic clocks" on their walls. >>> >>> Bob >>> >>> -Original Message- >>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >>> Behalf Of Don Henderickx >>> Sent: Monday, February 08, 2010 4:07 PM >>> To: Discussion of precise time and frequency measurement >>> Subject: [time-nuts] True to there word. >>> >>> The lights went out (actually red) on my Austron 2100 r this morning. >>> (whats next WWVB ?) >>> Don H >>> >>> ___ >>> 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. > > ___ 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] The Smell of Tantalum in the Morning
While in the US Navy, we had to do equipment inspections. One quarterly was to examine the capacitors in the power supply of one piece of equipment. We were to look for leakage (sulfuric acid) from CL65 type wet slug tantalum capacitors. Shortly after that CL65 type capacitors were disapproved for military use. I never saw one that leaked in that equipment, but, have seen a number of boards damaged from seal leakage on CL65 capacitors. Something to look out for. The CL65 capacitors probably have a pure silver case a sulfuric acid as an electrolyte. The seal is Teflon. We also had an interesting failure mode for ATC ceramic capacitors. This failure mode will only occur in a sealed environment (submarine. Just an observation. 73 Glenn WB4UIV At 09:46 AM 2/8/2010, you wrote: The history of tantalum failures is wide and varied, but there are some common characteristics: 1) The tantalum is in a power supply circuit and receives a rapid ramp from 0V to operating voltage. 2) The tantalum is spec'd close to its operating voltage, very close 5V on a 6.3V part, 12.5V on a 15V part... 3) The tantalum is dry slug, and is sealed with epoxy. 4) The instrument has been powered down for an extended period. HP equipment from the 1980's is pretty immune to the problem because they typically use hermetically sealed mil spec tantalum capacitors. Tektronix equipment from the 1980's is infested with tantalum problems because they used the cheap epoxy dipped parts. Tantalum failures are pretty rare in equipment that is run continuously. Tantalum has a self healing feature that corrects any small problems while in operating... Large problems result in detonation. Dipped tantalum capacitors of any age are prone to failure. The tendency can be mitigated largely by never allowing a tantalum capacitor to see voltage above 50% of its rating. And finally, powering a tantalum in reverse, will cause instant and irreparable damage. -Chuck Harris Tom Van Baak wrote: I powered up a 5071A to watch the end of Loran-C today and was greeted by the special smell that only a mother board could love. Does anyone know the history of tantalum capacitor failures in ten-year old [HP/Agilent] test equipment? This is not my first. Last one was more like July 4th. Thanks, /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. ___ 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] True to there word. - Fancy WWVB
Hi People rarely want to use WWVB mobile. The location of the transmitter and receiver can be looked up on a map. The time of sunrise at both locations should be something that could be calculated. Assuming you are willing to put up with all of that, you should be able to do a first order correction on the shifts. The question obviously is - just how good would the net result be? Is it a 5:1 sort of thing or do you get a couple of orders of magnitude? Bob On Feb 8, 2010, at 6:40 PM, J. Forster wrote: > Yes, but WWVB is a PITA to use (because of the diurnal shifts) compared to > LORAN. > > -John > > === > > >> Hi >> >> WWVB is pretty safe. When they do a cost/benefit thing on these services, >> they take a look at how many taxpayers are using the service as intended. >> The "mission" of WWWVB is to put out time signals. There are a *lot* of >> taxpayers with WWVB "atomic clocks" on their walls. >> >> Bob >> >> -Original Message- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >> Behalf Of Don Henderickx >> Sent: Monday, February 08, 2010 4:07 PM >> To: Discussion of precise time and frequency measurement >> Subject: [time-nuts] True to there word. >> >> The lights went out (actually red) on my Austron 2100 r this morning. >> (whats next WWVB ?) >> Don H >> >> ___ >> 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] NOS Thunderbolts for sale (w/D1 temp sensor)
Gosh, I never suspected you swung that way, Bill... ;-) geo Bill Hawkins wrote: No thanks, George. If I bought one, I'd have to use Lady Heather, and I'd never use a lady. Bill Hawkins -Original Message- From: George Dubovsky Sent: Monday, February 08, 2010 1:58 PM I have three, essentially new Trimble Thunderbolt OEM boards for sale. ... 73, geo - n4ua ___ 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] Frequency comparison
Joop wrote: Yes, I noticed these things take time ;-) This is what I logged after everthing was powered on for over 24 hours And this is with the LPRO is cold started. About 5 minutes after lock. The GPS was already running for about an hour I have to guess. It is less flat at the last two hours than what I was hoping for. There is a reason that precision oscillators are often specified for stability "after running continuously for a period of [x]," where "x" is generally from one week to 90 days, sometimes even longer. They are not really made to be turned on and off, even if you let them settle for a matter of hours. Even with a GPSDO, the performance for small tau isn't really at its best until the unit has been on for weeks to months. What range of tau is "small" depends on how you tune your disciplining dynamics. I have found that the Tbolts in my limited very sample (2 units) work best with TC = 500 to 2000 seconds (bear in mind that I don't care about the PPS output, just the 10 MHz frequency), so for me "small" tau are those less than about 1000. Note that the improvement in small-tau stability probably won't appear in an ADEV plot that uses the received GPS time for comparison, because the oscillator is more stable than the GPS receiver at small tau -- so you're essentially measuring the GPS, not the oscillator. It is best to leave your stable quartz and Rubidium oscillators running continuously, preferably on a UPS in case of power failure, for best results. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] True to there word.
Yes, but WWVB is a PITA to use (because of the diurnal shifts) compared to LORAN. -John === > Hi > > WWVB is pretty safe. When they do a cost/benefit thing on these services, > they take a look at how many taxpayers are using the service as intended. > The "mission" of WWWVB is to put out time signals. There are a *lot* of > taxpayers with WWVB "atomic clocks" on their walls. > > Bob > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Don Henderickx > Sent: Monday, February 08, 2010 4:07 PM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] True to there word. > > The lights went out (actually red) on my Austron 2100 r this morning. > (whats next WWVB ?) > Don H > > ___ > 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] Frequency comparison
Hi, I am setting up an LPRO in a steel box (for a little additional magnetic shielding). The power supply is a linear in a separate box (separate the magnetic fields). In the LPRO box is a 5V voltage reference (2 x LT1009) which is used across a pair of trim pots (coarse and fine) with two front panel jacks for a high impedance DVM to set the frequency trim voltage f the LPRO. The LPRO is insulated with more than an inch of foam plastic and a small fan (on the outside of the box) is used to control the 1/2 inch aluminium plate that the LPRO is bolted to to about 38*C. The temperature control is much better than 1/10 degree. Inside the box is a decimal divider with outputs down to 1Hz, and a phase detector composed of 2 D latches (CMOS) the output of which is filtered and fed to a strip chart recorder or data logger. I have a TBOLT connected to a decimal divider, so I can compare the phase with the LPRO. At 10kHz I get 1microsecond per month resolution ~ 2x10^12. As errors show up the trim voltage can be adjusted with the DVM by an amount that is easy to calculate. So with a bit of time and without much in the way of high precision timing gear I hope to be able to get the LPRO adjusted to the limits of its precision, and I avoid the short term fluctuations in the TBOLT output. After a year or so I will be able to tell you how well it works. cheers, Neville Michie ___ 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] NOS Thunderbolts for sale (w/D1 temp sensor)
No thanks, George. If I bought one, I'd have to use Lady Heather, and I'd never use a lady. Bill Hawkins -Original Message- From: George Dubovsky Sent: Monday, February 08, 2010 1:58 PM I have three, essentially new Trimble Thunderbolt OEM boards for sale. ... 73, geo - n4ua ___ 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] Frequency comparison
>Since the GPSDO takes > 1 1/2 hours to give an adequately accurate reading >to calibrate 1x10^-11, there's no rushing the process. That's not warm up >time, or lock time on the GPSDO. It's the time you need to watch if for in >order to know it's output frequency to a sufficient level of precision. > >Bob > Yes, I noticed these things take time ;-) This is what I logged after everthing was powered on for over 24 hours and adjusted. It is a 2 hour period during which no adjustments were made. http://www.uploadarchief.net/files/download/lpro_24h.png And this is with the LPRO is cold started. About 5 minutes after lock. The GPS was already running for about an hour I have to guess. The LPRO was not adjusted anymore. http://www.uploadarchief.net/files/download/lpro_start7h.png It is less flat at the last two hours than what I was hoping for. Joop ___ 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] Frequency comparison
Hi With the 1 pps approach, you can spot jumps or shifts of >1,000,000 cycles worth of 10MHz without major trouble. With a mixer approach spotting a slip of jump of one cycle can be difficult. The difference sounds pretty minor. If you are looking for odd things happening over a period of many days, it's pretty significant. At 1x10^-11 frequency offset: The mixer goes through one cycle of 10 MHz in ~ 3 hours. The counters go through one cycle of 1 pps in ~ 3,000 years. If the Rb is at 1x10^-9 the numbers are 100X quicker. Since the GPSDO takes > 1 1/2 hours to give an adequately accurate reading to calibrate 1x10^-11, there's no rushing the process. That's not warm up time, or lock time on the GPSDO. It's the time you need to watch if for in order to know it's output frequency to a sufficient level of precision. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joop Sent: Monday, February 08, 2010 4:27 PM To: Joop Cc: time-nuts@febo.com Subject: [time-nuts] Frequency comparison At 07-02-10, John Ackermann wrote: >Hi Raj -- > >You've already gotten some good answers. If all you want to do is >measure the frequency offset rather than characterize the stability, a >simple approach is to first get as close as you can by adjust for >minimum march of the 10 MHz signals across the oscilloscope, then use >either the Racal counter or the digital o'scope to measure the delay >between the two signals and how it changes over time, preferably >measuring at 1 PPS rather than 10 MHz. > >In other words, measure the time difference between the leading edge of >the PPS signals, averaging for a while (depending on how close the two >already are) to improve resolution and reduce the noise. Write down the >delay figure, note the wall clock time, wait a while, then come back and >measure the delay again. The change in delay over the elapsed time will >tell you the frequency offset, e.g., if you see 1 microsecond per day, >that's 1.16x10e-11. > >Adjust and repeat. As others have mentioned, being a time-nut requires >patience. :-) > >It's best to do this at a lower frequency than 10 MHz, and ideally at 1 >PPS, as there's only 100 nanoseconds between cycle slips at 10 MHz, and >that limits how long you'll be able to measure before you've drifted a >complete cycle. > >73, >John > Ok, the past few days I have been working on exactly the same thing. That is, adjust an LPRO to my homemade GPSDO. Good to know I followed a proven procedure. Initially I wanted to build two PPSDIV/TADD circuits but did not have the right PICs. Instead I used two PIC12F devices and put them on the same veroboard. The software for only a single 1Hz output was not too complex. There was also a Racal 1992 I could use to measure and log the phase shift. If that would not have been the case I probably would have tried a XOR port to both (synched) outputs and use an R + C to measure the DC voltage. That would make a nice little gadget for people not having a high-res counter. Also the TADD 74AC04 drivers would not be needed this way. Anyway, I finally dared to adjust the LPRO. Can somebody tell if the following seems normal? * The LPRO measured 1.77 E-10 high (before any adjustment) * Lamp voltage is about 5.7V * The GPSDO 1Hz pulse seems to move (noise like) + or - 15ns around its linear regression line * The LPRO takes more than 8 hours (perhaps even 24) to reach the 1E-11 level? The last point is guessing since my GPS signal is super stable. I thought I managed to adjust it to that level after the LPRO had been powered on for more than 24 hours. But powering it on two days later shows a higher drift after 5 hours than where left before. Also I would like to know if I have to repeat this procedure once it is built into its final enclosure. Right now it is open on the bench and clamped to a heatsink. Temperature might be different inside a box. Cheers, Joop ___ 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] True to there word.
Hi WWVB is pretty safe. When they do a cost/benefit thing on these services, they take a look at how many taxpayers are using the service as intended. The "mission" of WWWVB is to put out time signals. There are a *lot* of taxpayers with WWVB "atomic clocks" on their walls. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Don Henderickx Sent: Monday, February 08, 2010 4:07 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] True to there word. The lights went out (actually red) on my Austron 2100 r this morning. (whats next WWVB ?) Don H ___ 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] Frequency comparison
On Mon, 08 Feb 2010 22:26:44 +0100, Joop wrote: > The last point is guessing since my GPS signal is super stable. I thought Here I meant of course that my GPS 1Hz signal is NOT super stable. Well, I thought it was until I bought the LPRO ;-) Cheers, Joop ___ 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] Frequency comparison
At 07-02-10, John Ackermann wrote: >Hi Raj -- > >You've already gotten some good answers. If all you want to do is >measure the frequency offset rather than characterize the stability, a >simple approach is to first get as close as you can by adjust for >minimum march of the 10 MHz signals across the oscilloscope, then use >either the Racal counter or the digital o'scope to measure the delay >between the two signals and how it changes over time, preferably >measuring at 1 PPS rather than 10 MHz. > >In other words, measure the time difference between the leading edge of >the PPS signals, averaging for a while (depending on how close the two >already are) to improve resolution and reduce the noise. Write down the >delay figure, note the wall clock time, wait a while, then come back and >measure the delay again. The change in delay over the elapsed time will >tell you the frequency offset, e.g., if you see 1 microsecond per day, >that's 1.16x10e-11. > >Adjust and repeat. As others have mentioned, being a time-nut requires >patience. :-) > >It's best to do this at a lower frequency than 10 MHz, and ideally at 1 >PPS, as there's only 100 nanoseconds between cycle slips at 10 MHz, and >that limits how long you'll be able to measure before you've drifted a >complete cycle. > >73, >John > Ok, the past few days I have been working on exactly the same thing. That is, adjust an LPRO to my homemade GPSDO. Good to know I followed a proven procedure. Initially I wanted to build two PPSDIV/TADD circuits but did not have the right PICs. Instead I used two PIC12F devices and put them on the same veroboard. The software for only a single 1Hz output was not too complex. There was also a Racal 1992 I could use to measure and log the phase shift. If that would not have been the case I probably would have tried a XOR port to both (synched) outputs and use an R + C to measure the DC voltage. That would make a nice little gadget for people not having a high-res counter. Also the TADD 74AC04 drivers would not be needed this way. Anyway, I finally dared to adjust the LPRO. Can somebody tell if the following seems normal? * The LPRO measured 1.77 E-10 high (before any adjustment) * Lamp voltage is about 5.7V * The GPSDO 1Hz pulse seems to move (noise like) + or - 15ns around its linear regression line * The LPRO takes more than 8 hours (perhaps even 24) to reach the 1E-11 level? The last point is guessing since my GPS signal is super stable. I thought I managed to adjust it to that level after the LPRO had been powered on for more than 24 hours. But powering it on two days later shows a higher drift after 5 hours than where left before. Also I would like to know if I have to repeat this procedure once it is built into its final enclosure. Right now it is open on the bench and clamped to a heatsink. Temperature might be different inside a box. Cheers, Joop ___ 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] Frequency comparison
You need to use a mixer with low dc offset for best results. Try one of the Minicircuits phase detectors (RPD-1, MPD-1, SYPD-1 etc) These have low dc offset and dc offset drift. Bruce Raj wrote: Hi Dan, Low tech. Yes! IMHO I think its easier for my mind to track an analog indication of Delta-V. I am more analog oriented.. my son OTOH may be able to read a last digit flickering digital display better than me!. I am other wise thinking of a DIY gizmo: Mix two signals in an SBL1 or Eq. Take the phase/DC IF difference out Make a zero crossing detector or similar Timimg the event. Wait for the event in other words! Twiddle the preset again and see what happens. The human mind does a lot more processing than the above with an analog display.. Cheers Raj, vu2zap Raj wrote: I was thinking of feeding two 10 Mhz signals to two ports of a SBL-1 or similar and taking the DC output at the IF port into an opamp or analog meter. This was visually easier to adjust the drift between two frequencies by just watching the needle move. A stationary needle over a couple of hours would be the best! Raj, I did exactly this but with an old chart recorder attached to the mixer IF port. This allows one to leave the room and not have to watch for hours or days. I was able to adjust my -hp- rubidium unit this way against gps to better than one cycle per day. Low tech but effective. Dan ___ 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] True to there word.
The lights went out (actually red) on my Austron 2100 r this morning. (whats next WWVB ?) Don H ___ 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] The Smell of Tantalum in the Morning
I've seen the butt weld (or crimp) of the wire in hermetic units fail due to corrosion in both HP and Tek gear. In all cases (about 6), the gear appeared to not have been protected too well from the elements, or was exposed to high humidity for a long time. The good news is that it fails open and is pretty obvious. Dave - Original Message - From: "Chuck Harris" To: "Discussion of precise time and frequency measurement" Sent: Monday, February 8, 2010 6:46:54 AM GMT -08:00 US/Canada Pacific Subject: Re: [time-nuts] The Smell of Tantalum in the Morning The history of tantalum failures is wide and varied, but there are some common characteristics: 1) The tantalum is in a power supply circuit and receives a rapid ramp from 0V to operating voltage. 2) The tantalum is spec'd close to its operating voltage, very close 5V on a 6.3V part, 12.5V on a 15V part... 3) The tantalum is dry slug, and is sealed with epoxy. 4) The instrument has been powered down for an extended period. HP equipment from the 1980's is pretty immune to the problem because they typically use hermetically sealed mil spec tantalum capacitors. Tektronix equipment from the 1980's is infested with tantalum problems because they used the cheap epoxy dipped parts. Tantalum failures are pretty rare in equipment that is run continuously. Tantalum has a self healing feature that corrects any small problems while in operating... Large problems result in detonation. Dipped tantalum capacitors of any age are prone to failure. The tendency can be mitigated largely by never allowing a tantalum capacitor to see voltage above 50% of its rating. And finally, powering a tantalum in reverse, will cause instant and irreparable damage. -Chuck Harris Tom Van Baak wrote: > I powered up a 5071A to watch the end of Loran-C today > and was greeted by the special smell that only a mother > board could love. > > Does anyone know the history of tantalum capacitor > failures in ten-year old [HP/Agilent] test equipment? > This is not my first. Last one was more like July 4th. > > Thanks, > /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. ___ 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] NOS Thunderbolts for sale (w/D1 temp sensor)
Time-nuts; I have three, essentially new Trimble Thunderbolt OEM boards for sale. These were part of a production lot that had been returned to Trimble (several years ago) from the OEM because the wrong zener had been installed in the voltage sense circuit. This is the zener that allows the unit to work from -7 Vdc (instead of the Trimble-standard -12 Vdc) without the Power Supply alarm being invoked. Trimble changed the diodes, and the units were returned to the OEM; these three were never installed in production units. In fact, they are still sealed in the anti-stat bags that Trimble shipped them in. This is the connectorized board that is normally mounted inside the gold-colored aluminum case that everyone is familiar with. The units have version 2.2 firmware, and all have the older D1 date code DS1620 thermometer chip with the smaller temperature steps. $150 each for the board assembly in the sealed bag; for another $10, I will install the board in a case and throw in a power connector. Or, I can supply the case and you can install the board. All, plus $5 each for flat-rate shipping. 73, geo - n4ua ___ 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] No 1 PPS output on a Tbolt
Hi I keep an old fashion "logic probe" lying around for this sort of thing. If the light flashes, I have a signal. Much easier than a scope. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joseph M Gwinn Sent: Monday, February 08, 2010 12:21 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] No 1 PPS output on a Tbolt The 1PPS signal is actually quite strong. I would hook a telephone receiver or perhaps a little speaker to the 1PPS output and listen. The signal should make an audible click once per second. Joe Gwinn time-nuts-boun...@febo.com wrote on 02/08/2010 12:01:46 PM: > From: > > Mark Sims > > To: > > > > Date: > > 02/08/2010 12:11 PM > > Subject: > > [time-nuts] No 1 PPS output on a Tbolt > > Sent by: > > time-nuts-boun...@febo.com > > > Make sure that the 1 PPS output is enabled... It can be > turned off by software and that mode can be set in EEPROM. > > Also, many scopes have great difficulty showing a 10 uS pulse > at a 1 PPS rep rate. Digital scopes might not sample it in > normal display modes (envelope or glitch capture mode can > help). It can easily get lost on an analog display... > _ > Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. > http://clk.atdmt.com/GBL/go/201469229/direct/01/ > ___ > 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] Frequency comparison
Hi If you mix the RB and GPS down with a mixer you eventually will run into a problem. As you set them both very close to frequency, the output is a noisy DC signal rather than a sine wave. Since each source can drift either up or down for a short period of time, it can be hard to tell what's going on with a zero crossing detector. It is much better to capture the output voltage with a strip chart or the digital equivalent. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Raj Sent: Monday, February 08, 2010 10:34 AM To: dan...@verizon.net; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Frequency comparison Hi Dan, Low tech. Yes! IMHO I think its easier for my mind to track an analog indication of Delta-V. I am more analog oriented.. my son OTOH may be able to read a last digit flickering digital display better than me!. I am other wise thinking of a DIY gizmo: Mix two signals in an SBL1 or Eq. Take the phase/DC IF difference out Make a zero crossing detector or similar Timimg the event. Wait for the event in other words! Twiddle the preset again and see what happens. The human mind does a lot more processing than the above with an analog display.. Cheers Raj, vu2zap >Raj wrote: >> >>I was thinking of feeding two 10 Mhz signals to two ports of a SBL-1 or similar and taking the DC >>output at the IF port into an opamp or analog meter. This was visually easier to adjust the drift between two frequencies by just watching the needle move. A stationary needle over a couple of hours would be the best! >> >> >Raj, I did exactly this but with an old chart recorder attached to the mixer IF port. This allows one to leave the room and not have to watch for hours or days. I was able to adjust my -hp- rubidium unit this way against gps to better than one cycle per day. > >Low tech but effective. > >Dan > > >___ >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. -- Raj, VU2ZAP Bangalore, India. ___ 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] No 1 PPS output on a Tbolt
The 1PPS signal is actually quite strong. I would hook a telephone receiver or perhaps a little speaker to the 1PPS output and listen. The signal should make an audible click once per second. Joe Gwinn time-nuts-boun...@febo.com wrote on 02/08/2010 12:01:46 PM: > From: > > Mark Sims > > To: > > > > Date: > > 02/08/2010 12:11 PM > > Subject: > > [time-nuts] No 1 PPS output on a Tbolt > > Sent by: > > time-nuts-boun...@febo.com > > > Make sure that the 1 PPS output is enabled... It can be > turned off by software and that mode can be set in EEPROM. > > Also, many scopes have great difficulty showing a 10 uS pulse > at a 1 PPS rep rate. Digital scopes might not sample it in > normal display modes (envelope or glitch capture mode can > help). It can easily get lost on an analog display... > _ > Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. > http://clk.atdmt.com/GBL/go/201469229/direct/01/ > ___ > 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] No 1 PPS output on a Tbolt
Make sure that the 1 PPS output is enabled... It can be turned off by software and that mode can be set in EEPROM. Also, many scopes have great difficulty showing a 10 uS pulse at a 1 PPS rep rate. Digital scopes might not sample it in normal display modes (envelope or glitch capture mode can help). It can easily get lost on an analog display... _ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. http://clk.atdmt.com/GBL/go/201469229/direct/01/ ___ 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] Measuring frequency difference
Raj wrote: I must again check with a newer GPS for better coordinate accuracy. Initially only two SV's lit green, after I set the co-ordinates then all are green. Now the 10MHz is jumping between <0.1 >0.00 ppb. comparing with a a FE5680. I understand that is mostly due to using the default settings on the TBOLT. There are several here who have devoted much time and energy to the fine art of TBOLT manipulation. I decided against trying to use the TBOLT for timing and dedicated it to be a frequency reference for a Ham repeater where it has performed very well. Closer to its original use. If you want to use it as a frequency standard for setting Rubidiums and OCXOs, it should be OK as those time jumps will average out over the long term anyway. ___ 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] Frequency comparison
Anyone who would like to clone the HP K34-59991A Pase Comparator? Maybe just add a 'maginfier'. Adrian Dan Rae schrieb: Raj wrote: I was thinking of feeding two 10 Mhz signals to two ports of a SBL-1 or similar and taking the DC output at the IF port into an opamp or analog meter. This was visually easier to adjust the drift between two frequencies by just watching the needle move. A stationary needle over a couple of hours would be the best! Raj, I did exactly this but with an old chart recorder attached to the mixer IF port. This allows one to leave the room and not have to watch for hours or days. I was able to adjust my -hp- rubidium unit this way against gps to better than one cycle per day. Low tech but effective. Dan ___ 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] Frequency comparison
Hi Dan, Low tech. Yes! IMHO I think its easier for my mind to track an analog indication of Delta-V. I am more analog oriented.. my son OTOH may be able to read a last digit flickering digital display better than me!. I am other wise thinking of a DIY gizmo: Mix two signals in an SBL1 or Eq. Take the phase/DC IF difference out Make a zero crossing detector or similar Timimg the event. Wait for the event in other words! Twiddle the preset again and see what happens. The human mind does a lot more processing than the above with an analog display.. Cheers Raj, vu2zap >Raj wrote: >> >>I was thinking of feeding two 10 Mhz signals to two ports of a SBL-1 or >>similar and taking the DC >>output at the IF port into an opamp or analog meter. This was visually easier >>to adjust the drift between two frequencies by just watching the needle move. >>A stationary needle over a couple of hours would be the best! >> >> >Raj, I did exactly this but with an old chart recorder attached to the mixer >IF port. This allows one to leave the room and not have to watch for hours or >days. I was able to adjust my -hp- rubidium unit this way against gps to >better than one cycle per day. > >Low tech but effective. > >Dan > > >___ >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. -- Raj, VU2ZAP Bangalore, India. ___ 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] No 1 PPS output on a Tbolt
Thank You so much for all the great responses for the Tbolt 1 PPS measurements and suggestions how to measure the output of the 1 PPS, unfortunately I am not able to see any output at all, I will contact the seller and make arrangements for an exchange, he is away for about two weeks, I will wait and what he suggests to do. Thank You so much for all Your help, a great group of well informed peoples. Best regards, Sal C. Cornacchia Electronic RF Microwave Engineer (Ret.) From: Robert Darlington To: Discussion of precise time and frequency measurement Sent: Mon, February 8, 2010 10:15:32 AM Subject: Re: [time-nuts] No 1 PPS output on a Tbolt Try hooking the output to an LED. It's very difficult for me to see the pulse on my analog scopes but there is no arguing with the blinking light. -Bob On Mon, Feb 8, 2010 at 8:05 AM, SAL CORNACCHIA wrote: > Thank You John, I have tried with different sweep speeds both above and > below 100 us/div, the problem appears to be no output at all. > > Best regards, > > Sal C. Cornacchia > Electronic RF Microwave Engineer (Ret.) > > > > > > > > > From: John Ackermann N8UR > To: Discussion of precise time and frequency measurement < > time-nuts@febo.com> > Sent: Sun, February 7, 2010 8:45:06 PM > Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > > Sal, what sweep time are you using on the scope? I believe the TBolt > PPS is only microseconds wide, so you may need to speed up the sweep > time to around 100us/div or faster to see it accurately. And you may > need to mess with delaying the sweep to get the pulse on the screen. > > John > > > SAL CORNACCHIA said the following on 02/07/2010 08:32 PM: > > I cannot measure anything, with the scope set at max sensitivity, there > is only a tiny dot indication every second. > > > > Best regards, > > > > Sal C. Cornacchia > > Electronic RF Microwave Engineer (Ret.) > > > > > > > > > > > > > > > > From: Bruce Griffiths > > To: Discussion of precise time and frequency measurement < > time-nuts@febo.com> > > Sent: Sun, February 7, 2010 7:45:26 PM > > Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > > > > Any idea what the pulse shapes you see is with a 1M load and with a 50 > > ohm load? > > > > Bruce > > > > SAL CORNACCHIA wrote: > >> Hi Didier, > >> > >> When the 50 ohms termination is switch on the oscilloscope there is a > tiny positive dot deflecting every second, it appears to have a very low > output. > >> Best regards, > >> Sal C. Cornacchia > >> Electronic RF Microwave Engineer (Ret.) > >> > >> > >> > >> > >> > >> > >> > >> > >> From: Didier Juges > >> To: Time-Nuts > >> Sent: Sun, February 7, 2010 11:51:15 AM > >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >> > >> The pulse is narrow, but it should be a full 5V amplitude. The driver is > pretty beefy, the amplitude does dot drop appreciably when loaded with 50 > ohms on mine. > >> > >> Didier KO4BB > >> > >> Sent from my BlackBerry Wireless thingy while I > do other things... > >> > >> -Original Message- > >> From: SAL CORNACCHIA > >> Date: Sun, 7 Feb 2010 08:42:49 > >> To: Discussion of precise time and frequency measurement< > time-nuts@febo.com> > >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >> > >> Hi Bob, > >> The pulse is barely visible on the Tektronix 485 it appears to be a very > low output. > >> Best regards, > >> Sal C. Cornacchia > >> Electronic RF Microwave Engineer (Ret.) > >> > >> > >> > >> > >> > >> > >> > >> > >> From: Bob Camp > >> To: Discussion of precise time and frequency measurement .com> > >> Sent: Sun, February 7, 2010 11:26:16 AM > >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >> > >> Hi > >> > >> The 5345 should see it if it's set to 50 ohm termination and DC > coupling.. A > >> sweep of the trigger from about 1.5 to 3.5 volts should show it there > over > >> most of the sweep. > >> > >> Bob > >> > >> -- > >> From: "SAL CORNACCHIA" > >> Sent: Sunday, February 07, 2010 11:06 AM > >> To: "Discussion of precise time and frequency measurement" > >> > >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >> > >> > >>> Oscilloscope and 5345A Counter, the Tbolt software shows all green. > >>> Best regards, > >>> Sal C. Cornacchia > >>> Electronic RF Microwave Engineer (Ret.) > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> From: "Stan, W1LE" > >>> To: Discussion of precise time and frequency measurement > >>> > >>> Sent: Sun, February 7, 2010 10:47:42 AM > >>> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >>> > >>> Hello Sal, > >>> > >>> What are you monitoring the PPS output with ?? > >>> > >>> It is a short duration pulse. > >>> > >>> What does the TboltMON software (available at the trimbl
Re: [time-nuts] No 1 PPS output on a Tbolt
Try hooking the output to an LED. It's very difficult for me to see the pulse on my analog scopes but there is no arguing with the blinking light. -Bob On Mon, Feb 8, 2010 at 8:05 AM, SAL CORNACCHIA wrote: > Thank You John, I have tried with different sweep speeds both above and > below 100 us/div, the problem appears to be no output at all. > > Best regards, > > Sal C. Cornacchia > Electronic RF Microwave Engineer (Ret.) > > > > > > > > > From: John Ackermann N8UR > To: Discussion of precise time and frequency measurement < > time-nuts@febo.com> > Sent: Sun, February 7, 2010 8:45:06 PM > Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > > Sal, what sweep time are you using on the scope? I believe the TBolt > PPS is only microseconds wide, so you may need to speed up the sweep > time to around 100us/div or faster to see it accurately. And you may > need to mess with delaying the sweep to get the pulse on the screen. > > John > > > SAL CORNACCHIA said the following on 02/07/2010 08:32 PM: > > I cannot measure anything, with the scope set at max sensitivity, there > is only a tiny dot indication every second. > > > > Best regards, > > > > Sal C. Cornacchia > > Electronic RF Microwave Engineer (Ret.) > > > > > > > > > > > > > > > > From: Bruce Griffiths > > To: Discussion of precise time and frequency measurement < > time-nuts@febo.com> > > Sent: Sun, February 7, 2010 7:45:26 PM > > Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > > > > Any idea what the pulse shapes you see is with a 1M load and with a 50 > > ohm load? > > > > Bruce > > > > SAL CORNACCHIA wrote: > >> Hi Didier, > >> > >> When the 50 ohms termination is switch on the oscilloscope there is a > tiny positive dot deflecting every second, it appears to have a very low > output. > >> Best regards, > >> Sal C. Cornacchia > >> Electronic RF Microwave Engineer (Ret.) > >> > >> > >> > >> > >> > >> > >> > >> > >> From: Didier Juges > >> To: Time-Nuts > >> Sent: Sun, February 7, 2010 11:51:15 AM > >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >> > >> The pulse is narrow, but it should be a full 5V amplitude. The driver is > pretty beefy, the amplitude does dot drop appreciably when loaded with 50 > ohms on mine. > >> > >> Didier KO4BB > >> > >> Sent from my BlackBerry Wireless thingy while I > do other things... > >> > >> -Original Message- > >> From: SAL CORNACCHIA > >> Date: Sun, 7 Feb 2010 08:42:49 > >> To: Discussion of precise time and frequency measurement< > time-nuts@febo.com> > >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >> > >> Hi Bob, > >> The pulse is barely visible on the Tektronix 485 it appears to be a very > low output. > >> Best regards, > >> Sal C. Cornacchia > >> Electronic RF Microwave Engineer (Ret.) > >> > >> > >> > >> > >> > >> > >> > >> > >> From: Bob Camp > >> To: Discussion of precise time and frequency measurement .com> > >> Sent: Sun, February 7, 2010 11:26:16 AM > >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >> > >> Hi > >> > >> The 5345 should see it if it's set to 50 ohm termination and DC > coupling.. A > >> sweep of the trigger from about 1.5 to 3.5 volts should show it there > over > >> most of the sweep. > >> > >> Bob > >> > >> -- > >> From: "SAL CORNACCHIA" > >> Sent: Sunday, February 07, 2010 11:06 AM > >> To: "Discussion of precise time and frequency measurement" > >> > >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >> > >> > >>> Oscilloscope and 5345A Counter, the Tbolt software shows all green. > >>>Best regards, > >>> Sal C. Cornacchia > >>> Electronic RF Microwave Engineer (Ret.) > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> From: "Stan, W1LE" > >>> To: Discussion of precise time and frequency measurement > >>> > >>> Sent: Sun, February 7, 2010 10:47:42 AM > >>> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > >>> > >>> Hello Sal, > >>> > >>> What are you monitoring the PPS output with ?? > >>> > >>> It is a short duration pulse. > >>> > >>> What does the TboltMON software (available at the trimble website) show > ? > >>> > >>> What does Lady Heather indicate ? > >>> (She is just waiting to massage your numbers.) > >>> > >>> Stan, W1LE > >>> > >>> > >>> > >>> > > > > > > > > ___ > > 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 li
Re: [time-nuts] Frequency comparison
Raj wrote: I was thinking of feeding two 10 Mhz signals to two ports of a SBL-1 or similar and taking the DC output at the IF port into an opamp or analog meter. This was visually easier to adjust the drift between two frequencies by just watching the needle move. A stationary needle over a couple of hours would be the best! Raj, I did exactly this but with an old chart recorder attached to the mixer IF port. This allows one to leave the room and not have to watch for hours or days. I was able to adjust my -hp- rubidium unit this way against gps to better than one cycle per day. Low tech but effective. Dan ___ 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] No 1 PPS output on a Tbolt
Thank You John, I have tried with different sweep speeds both above and below 100 us/div, the problem appears to be no output at all. Best regards, Sal C. Cornacchia Electronic RF Microwave Engineer (Ret.) From: John Ackermann N8UR To: Discussion of precise time and frequency measurement Sent: Sun, February 7, 2010 8:45:06 PM Subject: Re: [time-nuts] No 1 PPS output on a Tbolt Sal, what sweep time are you using on the scope? I believe the TBolt PPS is only microseconds wide, so you may need to speed up the sweep time to around 100us/div or faster to see it accurately. And you may need to mess with delaying the sweep to get the pulse on the screen. John SAL CORNACCHIA said the following on 02/07/2010 08:32 PM: > I cannot measure anything, with the scope set at max sensitivity, there is > only a tiny dot indication every second. > > Best regards, > > Sal C. Cornacchia > Electronic RF Microwave Engineer (Ret.) > > > > > > > > From: Bruce Griffiths > To: Discussion of precise time and frequency measurement > Sent: Sun, February 7, 2010 7:45:26 PM > Subject: Re: [time-nuts] No 1 PPS output on a Tbolt > > Any idea what the pulse shapes you see is with a 1M load and with a 50 > ohm load? > > Bruce > > SAL CORNACCHIA wrote: >> Hi Didier, >> >> When the 50 ohms termination is switch on the oscilloscope there is a tiny >> positive dot deflecting every second, it appears to have a very low output. >> Best regards, >> Sal C. Cornacchia >> Electronic RF Microwave Engineer (Ret.) >> >> >> >> >> >> >> >> >> From: Didier Juges >> To: Time-Nuts >> Sent: Sun, February 7, 2010 11:51:15 AM >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt >> >> The pulse is narrow, but it should be a full 5V amplitude. The driver is >> pretty beefy, the amplitude does dot drop appreciably when loaded with 50 >> ohms on mine. >> >> Didier KO4BB >> >> Sent from my BlackBerry Wireless thingy while I do >> other things... >> >> -Original Message- >> From: SAL CORNACCHIA >> Date: Sun, 7 Feb 2010 08:42:49 >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt >> >> Hi Bob, >> The pulse is barely visible on the Tektronix 485 it appears to be a very low >> output. >> Best regards, >> Sal C. Cornacchia >> Electronic RF Microwave Engineer (Ret.) >> >> >> >> >> >> >> >> >> From: Bob Camp >> To: Discussion of precise time and frequency measurement >> Sent: Sun, February 7, 2010 11:26:16 AM >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt >> >> Hi >> >> The 5345 should see it if it's set to 50 ohm termination and DC coupling.. A >> sweep of the trigger from about 1.5 to 3.5 volts should show it there over >> most of the sweep. >> >> Bob >> >> -- >> From: "SAL CORNACCHIA" >> Sent: Sunday, February 07, 2010 11:06 AM >> To: "Discussion of precise time and frequency measurement" >> >> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt >> >> >>> Oscilloscope and 5345A Counter, the Tbolt software shows all green. >>> Best regards, >>> Sal C. Cornacchia >>> Electronic RF Microwave Engineer (Ret.) >>> >>> >>> >>> >>> >>> >>> >>> >>> From: "Stan, W1LE" >>> To: Discussion of precise time and frequency measurement >>> >>> Sent: Sun, February 7, 2010 10:47:42 AM >>> Subject: Re: [time-nuts] No 1 PPS output on a Tbolt >>> >>> Hello Sal, >>> >>> What are you monitoring the PPS output with ?? >>> >>> It is a short duration pulse. >>> >>> What does the TboltMON software (available at the trimble website) show ? >>> >>> What does Lady Heather indicate ? >>> (She is just waiting to massage your numbers.) >>> >>> Stan, W1LE >>> >>> >>> >>> > > > > ___ > 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] The Smell of Tantalum in the Morning
The history of tantalum failures is wide and varied, but there are some common characteristics: 1) The tantalum is in a power supply circuit and receives a rapid ramp from 0V to operating voltage. 2) The tantalum is spec'd close to its operating voltage, very close 5V on a 6.3V part, 12.5V on a 15V part... 3) The tantalum is dry slug, and is sealed with epoxy. 4) The instrument has been powered down for an extended period. HP equipment from the 1980's is pretty immune to the problem because they typically use hermetically sealed mil spec tantalum capacitors. Tektronix equipment from the 1980's is infested with tantalum problems because they used the cheap epoxy dipped parts. Tantalum failures are pretty rare in equipment that is run continuously. Tantalum has a self healing feature that corrects any small problems while in operating... Large problems result in detonation. Dipped tantalum capacitors of any age are prone to failure. The tendency can be mitigated largely by never allowing a tantalum capacitor to see voltage above 50% of its rating. And finally, powering a tantalum in reverse, will cause instant and irreparable damage. -Chuck Harris Tom Van Baak wrote: I powered up a 5071A to watch the end of Loran-C today and was greeted by the special smell that only a mother board could love. Does anyone know the history of tantalum capacitor failures in ten-year old [HP/Agilent] test equipment? This is not my first. Last one was more like July 4th. Thanks, /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] The Smell of Tantalum in the Morning
I fired up a TEK 485 scope over the weekend and was greeted by a similar event. Sure smelled like tantalum but turned out it was a sacrificial 10 ohm resistor taken out by a shorted tantalum. I don't have any equipment that is only 10 years old. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Monday, February 08, 2010 4:15 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] The Smell of Tantalum in the Morning I powered up a 5071A to watch the end of Loran-C today and was greeted by the special smell that only a mother board could love. Does anyone know the history of tantalum capacitor failures in ten-year old [HP/Agilent] test equipment? This is not my first. Last one was more like July 4th. Thanks, /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] T-Bolt question.
I often don't receive my own post to the list at one time I wondered if it was the links in my post but I'm not so sure now. People have replied to my post with it included even though I never received it so I know the problem is not me to the list but the list to me. I have also noticed some posts are delayed for longer than normal. Suspect others have the same problem when they repost the same info twice. Stanley - Original Message From: Dave Baxter To: time-nuts@febo.com Sent: Mon, February 8, 2010 4:39:00 AM Subject: [time-nuts] T-Bolt question. Lastly, unrelated to "Time" (other than it's to do with this list.) Any (sensible) suggestions as to why I often miss a digest mail? Nothing ends up in the spam bucket, but I seem to miss about 1 in 8 digests at the moment, mostly individual digests, but sometimes a block of up to 4 go missing, that seems to happen just after the digest "volume" number increments. Cheers All. Dave B. G0WBX. ___ 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] T-Bolt question.
Yes the PPS will continue from the internal OCXO no Rubidium. http://trl.trimble.com/docushare/dsweb/Get/Document-10001/ThunderBoltBook2003.pdf I'm unaware of any firmware command to extend width. Stanley - Original Message From: Dave Baxter To: time-nuts@febo.com Sent: Mon, February 8, 2010 4:39:00 AM Subject: [time-nuts] T-Bolt question. A question (or two) if I may, not being a T'Bolt owner/user. (Yet.) Re the 1PPS output. Can it be selected to be wider than the 20uS or so illustrated recently, or will NTPD (on FreeBSD) work OK with that pulse "as is"? I know TAPR have a "FatPPS" kit, just a monostable in essance. http://www.tapr.org/kits_fatpps.html In case something *Needs* a wide pulse, and all you have is a pulse in the uS region. If the T'Bolt looses sight of the GPS satelite signals, does it continue to provide a 1PPS output, derived from the internal Rubidium oscilator? I think I read somewhere that it does continue to provide the 10MHz output, in the absence of GPS signals, once it has got itself sorted in the first place. Lastly, unrelated to "Time" (other than it's to do with this list.) Any (sensible) suggestions as to why I often miss a digest mail? Nothing ends up in the spam bucket, but I seem to miss about 1 in 8 digests at the moment, mostly individual digests, but sometimes a block of up to 4 go missing, that seems to happen just after the digest "volume" number increments. Cheers All. Dave B. G0WBX. ___ 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] Measuring frequency difference
I noticed the same John. I fired up the TBolt and it was not working fine till I set my location and height above sea level. Our city is about 928M ASL. I must again check with a newer GPS for better coordinate accuracy. Initially only two SV's lit green, after I set the co-ordinates then all are green. Now the 10MHz is jumping between <0.1 >0.00 ppb. comparing with a a FE5680. >I started out using an oscilloscope and comparing OCXOs to my Z3801 GPSDO. >Later I used it to compare an LPRO 101 to the Z3801 and finally, a TBOLT. I >later acquired a Racal 1992 which makes things a little easier but no more >accurate in my opinion. If you are looking at frequency difference or >frequency drift, and not stability, either of these methods and a stopwatch >will get pretty good results. It took me a couple of days to get an LPRO >adjusted so that I saw one cycle slip every few hours. It takes patience. >The thing that surprised me was how much a TBOLT moved around compared to my >Z3801. Though it stayed within one cycle because it was "phase locked", it >jumped around a good bit while the LPRO just slowly slipped in one direction >or the other. -- Raj, VU2ZAP Bangalore, India. ___ 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] The Smell of Tantalum in the Morning
I have a Philips counter where a Tantalum regularly fails in the oven. They also failed commonly in transceiver finals in the 80's >I powered up a 5071A to watch the end of Loran-C today >and was greeted by the special smell that only a mother >board could love. > >Does anyone know the history of tantalum capacitor >failures in ten-year old [HP/Agilent] test equipment? >This is not my first. Last one was more like July 4th. > >Thanks, >/tvb -- Raj, VU2ZAP Bangalore, India. ___ 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] T-Bolt question.
Hi Dave, 1) Tbolt 1PPS pulsewidth is not adjustable. 2) Yes, the Tbolt will give a 1PPS in holdover mode if there is no visable GPS satellites. (Its an crystal oven oscillator (OCXO) in a standard Tbolt not a Rubidium oscillator, even though it could be modified to dicipline an external oscillator of your choice.) -- Björn > A question (or two) if I may, not being a T'Bolt owner/user. (Yet.) > > Re the 1PPS output. > > Can it be selected to be wider than the 20uS or so illustrated recently, > or will NTPD (on FreeBSD) work OK with that pulse "as is"? I know TAPR > have a "FatPPS" kit, just a monostable in essance. > http://www.tapr.org/kits_fatpps.html > In case something *Needs* a wide pulse, and all you have is a pulse in > the uS region. > > > If the T'Bolt looses sight of the GPS satelite signals, does it continue > to provide a 1PPS output, derived from the internal Rubidium oscilator? > I think I read somewhere that it does continue to provide the 10MHz > output, in the absence of GPS signals, once it has got itself sorted in > the first place. > > > Lastly, unrelated to "Time" (other than it's to do with this list.) > Any (sensible) suggestions as to why I often miss a digest mail? > Nothing ends up in the spam bucket, but I seem to miss about 1 in 8 > digests at the moment, mostly individual digests, but sometimes a block > of up to 4 go missing, that seems to happen just after the digest > "volume" number increments. > > > Cheers All. > > Dave B. > G0WBX. > > > > ___ > 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] T-Bolt question.
A question (or two) if I may, not being a T'Bolt owner/user. (Yet.) Re the 1PPS output. Can it be selected to be wider than the 20uS or so illustrated recently, or will NTPD (on FreeBSD) work OK with that pulse "as is"? I know TAPR have a "FatPPS" kit, just a monostable in essance. http://www.tapr.org/kits_fatpps.html In case something *Needs* a wide pulse, and all you have is a pulse in the uS region. If the T'Bolt looses sight of the GPS satelite signals, does it continue to provide a 1PPS output, derived from the internal Rubidium oscilator? I think I read somewhere that it does continue to provide the 10MHz output, in the absence of GPS signals, once it has got itself sorted in the first place. Lastly, unrelated to "Time" (other than it's to do with this list.) Any (sensible) suggestions as to why I often miss a digest mail? Nothing ends up in the spam bucket, but I seem to miss about 1 in 8 digests at the moment, mostly individual digests, but sometimes a block of up to 4 go missing, that seems to happen just after the digest "volume" number increments. Cheers All. Dave B. G0WBX. ___ 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] The Smell of Tantalum in the Morning
I powered up a 5071A to watch the end of Loran-C today and was greeted by the special smell that only a mother board could love. Does anyone know the history of tantalum capacitor failures in ten-year old [HP/Agilent] test equipment? This is not my first. Last one was more like July 4th. Thanks, /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.
