[time-nuts] I wish to shorten GPS antenna cable - should I let receiver find the position again?
I have an HP 58503A which I am using as a frequency source only - not to tell the time. I want to shorted the antenna cable a bit, but are wondering if I should let the GPS receiver finds it position again. Or either of the following better * Remove antenna cable, put a new N plug on, and screw it back in with the receiver kept powered up all the time. * Power off GPS receiver and power it back on with the cable connected. I'm not moving the antenna, so the actual position will not change, but of course the signals will get to the receiver a bit sooner. Dave, G8WRB ___ time-nuts mailing 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] HP5328A HP5328B option 040
On 4/23/2015 9:20 AM, VK2DAP wrote: /1) Generally speaking, would it be correct to say that when a product model number changes from A to B,// //that represents an improvement or major update to a product?/ I remember having read (don't recall where...) that the HP5328B was a cost-reduction step wrt the A model... I had a model A, then sold it and bought a B. The B has the 10811 instead of the 10544 as OCXO, and its fan is much quieter than that of its older brother, very noisy. All considered, I would not go back... 73 Alberto I2PHD --- This email has been checked for viruses by Avast antivirus software. http://www.avast.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] Leica AT-303
Hi I guess it comes down to “how good is good enough?” With any L1 only system, you are up against uncorrectable ionosphere numbers in the =10 ns range. At 3 ns meter that is a 3 meter “variation”. The ionosphere does tend to correlate with that big light in the sky, so averaging over multiple days can address it in a position solution. Your TBolt will still wander around, since it’s loop time constant is 24 hours. If you are trying to take 12 -2/+40 ns per day down to 10 -2/+40 ns per day, then sure a ~5 mm accurate position will be better than a ~1 M location. It’s doubtful that there will be any measurable change in the TBolt’s output as a result. For $100, sure it’s not an expensive thing to try. I ummm ….. e .. seem to have a room full of antennas. My point is *not* let’s not do this. The point is that everybody does not need to run right out and go antenna crazy (like me). The TBolt works quite well on a proper outdoor timing antenna that has a very good view of the sky. Those antennas are nice and compact and sell for $50. Bob On Apr 23, 2015, at 3:04 AM, Mark Sims hol...@hotmail.com wrote: At least with a Tbolt, they do help... and quite a bit. When I was writing Lady Heather's precision survey code I tested it with several antennas (comparing the results to a cm level L1/L2 survey). The Leica antenna and a couple of other survey grade/choke ring antennas were, by far, the best (results with a foot or so). Cheap patch antennas were the worst (with maybe 5 foot errors). Some small L1 only survey grade antennas did pretty well... a couple of feet. They are about 6 inches in diameter and and inch thick and very light. I use one as my standard antenna. --- It’s not real clear that they have a significant advantage for L1 only operation with a Z3801. ___ time-nuts mailing 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] Leica AT-303
Hoi Mark, On Thu, 23 Apr 2015 07:04:04 + Mark Sims hol...@hotmail.com wrote: At least with a Tbolt, they do help... and quite a bit. When I was writing Lady Heather's precision survey code I tested it with several antennas [...] Cheap patch antennas were the worst (with maybe 5 foot errors). This might be due to the amount of side/back-lobes the patch antennas have. They basically relly on an (infitely) large ground plane beneath the antenna for back-lobe surpression. And most people I know use the patch antennas without any ground plane at all (me included). Some small L1 only survey grade antennas did pretty well... a couple of feet. They are about 6 inches in diameter and and inch thick and very light. I use one as my standard antenna. Which of the L1-only antennas did well? And do you have an explanation why the L1/L2 antennas did better, even for the L1-only reception case? Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ time-nuts mailing 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] Signal/Phase noise analyzer
Hi Any new gear that is self contained for phase noise testing will be above a basement budget ( $10K, some $100K). The simple approach is to use a single mixer / preamp and a second oscillator to do the measurement. You run the mixer output into an audio spectrum analyzer (possibly a sound card). Total cost for the setup can be $100, not including the computer and sound card. Bob On Apr 23, 2015, at 5:43 AM, Vasco Soares vesoa...@deea.isel.ipl.pt wrote: Thank you all for your reply's! It is for personal use, not a business. The budget it is very tight. I guess I can't find anything less that 2000-3000 euros even a second hand or a refurbished model. The main problem is that I'm starting from scratch... I found http://www.anapico.com/index.php/products/phase-noise-test-systems and the cheapest model (apph6000-is400) fits my needs (-160 dBc @ 100 Hz it is low enough) but it is too expensive (an outrageous of 18000 euros!). Their advantage, as in others, is to be a self contained analyzer with internal references. I don't know the price range of the Holzworth analyzer's but surely they are affordable compared with the one above. The model HA7402B needs two tunable LO, which I don't have, so a lot of investment has to be done. I can consider any setup as long as the above requirements are fulfilled and it is an affordable solution otherwise I've to wait for gather enough funds for this kind of investment. Regards, Vasco Soares - Original Message - From: Bob Camp kb...@n1k.org To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, April 22, 2015 11:36 PM Subject: Re: [time-nuts] Signal/Phase noise analyzer Hi Is this for a business or for a basement? Basement Are you looking for new self contained gear or combinations of used gear? Is a cross comparison device ok or do you need a stand alone device? How low do you need to go how fast? Is -190 dbc/ Hz low enough? Is a 24 hour run to long? Lots of variables…. Bob On Apr 22, 2015, at 10:07 AM, Vasco Soares vesoa...@deea.isel.ipl.pt wrote: Hi All, I'm searching for the less expensive signal analyzer to perform phase noise measurements on OCXO's. There is no need to go above 400 MHz - 1 GHz. I'm particularly interested on low frequency offset and good close in phase noise specs. Any recommendations? Best regards, Vasco Soares ___ time-nuts mailing 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] HP5328A HP5328B option 040
Nick, When HP step their product version, usually it is some significant changes to how the product is built. Some optional/new features sometimes get integrated in the process. I don't know why the TI-averaging feature of the Option 040/041/042 isn't available in the B version. Could be that when they got that far, they felt they had other products providing that feature and it was not widely used anyway. There can be many reasons why things get's dropped along the path. Would be fun to have a GPIB interface in the HP5328A. :) Cheers, Magnus On 04/23/2015 09:20 AM, VK2DAP wrote: Dear time-nuts, I have a question about the HP5328A and HP5328B universal counters. 1) Generally speaking, would it be correct to say that when a product model number changes from A to B, that represents an improvement or major update to a product? 2) I am interested in the delay option that is mentioned in the user manual for the HP5328A (option 040). My question is simple. Why does this option not feature in the HP5328B, but only as option 040 on the HP5328A? My first post on the time-nuts forum. I'm sorry if this question has previously been addressed. I made a search but was unable to find an answer. Regards, Nick Sent from my iPad ___ time-nuts mailing 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] HP5328A HP5328B option 040
On 4/23/2015 12:20 AM, VK2DAP wrote: Dear time-nuts, I have a question about the HP5328A and HP5328B universal counters. 1) Generally speaking, would it be correct to say that when a product model number changes from A to B, that represents an improvement or major update to a product? 2) I am interested in the delay option that is mentioned in the user manual for the HP5328A (option 040). My question is simple. Why does this option not feature in the HP5328B, but only as option 040 on the HP5328A? Now you have asked a very interesting question. Since you are new to time-nuts, you probably don't know I worked for HP/Agilent/Keysight for 35 years. It would be a gross oversimplification to assume that an A/B change is an improvement, although in some cases that may be true. Often it has more to do with certain parts becoming unavailable. You should also know that there is typically a 5 year support life after the product goes out of production. It is very common that they will increment the suffix to get the 5 year clock running so they no longer have to support very old instruments. This was certainly the case with the 5061B cesium standard. The nixie displays were unobtainium and we couldn't support the 5061A because of this. I don't know specifically about the 5328A vs B. However, I was the project manager for the 5334B counter. The way that came about was that I just happened to notice that there were various design aspects of the 5334A that wasted a lot of money. I didn't work in the counters section at the time, but nevertheless I annoyed the RD manager by pointing out these money leaks. I guess he got tired of hearing me complain and one day he offered my the job of project manager on a 5334B model. We needed to reduce cost because we were losing military contracts to Racal-Dana. I changed certain design details in the B model where I could save money. The idea was to simply keep the performance the same and not add features. There were many things I inherited from the A model that I left alone if I couldn't reduce the cost. We were also on a very tight schedule. This prevented me from replacing the 4 separate microprocessors in the 34A with a single one. (Very long story as to why this was) Now to get to your question about why a feature in the A version would not carry through to the B version. The 5334A had an option of a digital voltmeter, which was put in essentially because we could, but then justified after the fact by claiming that customers wanted it because some of them ordered the option. I never thought this made sense and used my authority as 5334B project manager to get rid of it in the 5334B. Since HP also sold voltmeters, they could always buy a voltmeter from our voltmeter division. There are a bunch of reasons why the 5328B would lose a feature that the 5328A had, but the point is that this doesn't break any rule. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] I wish to shorten GPS antenna cable - should I let receiver find the position again?
Le 23 avr. 2015 à 14:03, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk a écrit : I have an HP 58503A which I am using as a frequency source only - not to tell the time. I want to shorted the antenna cable a bit, but are wondering if I should let the GPS receiver finds it position again. Or either of the following better * Remove antenna cable, put a new N plug on, and screw it back in with the receiver kept powered up all the time. * Power off GPS receiver and power it back on with the cable connected. I'm not moving the antenna, so the actual position will not change, but of course the signals will get to the receiver a bit sooner. Just reconfigure the cable delay according to its new length. IIRC is 58503A uses the same SCPI command set last the Z3801A, so if that is the case that would be the command: :ptime:gpsystem:adelay nanoseconds NS Dave, G8WRB ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une petite et provisoire sécurité, ne méritent ni liberté ni sécurité. Benjimin Franklin ___ time-nuts mailing 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] I wish to shorten GPS antenna cable - should I let receiver find the position again?
Yes. You will get same location. Some GPS time receivers have cable length compensation for 1PPS output. Remember 1 foot is about 1 nano second error in 1PPS. Tim On Apr 23, 2015 1:15 PM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: I have an HP 58503A which I am using as a frequency source only - not to tell the time. I want to shorted the antenna cable a bit, but are wondering if I should let the GPS receiver finds it position again. Or either of the following better * Remove antenna cable, put a new N plug on, and screw it back in with the receiver kept powered up all the time. * Power off GPS receiver and power it back on with the cable connected. I'm not moving the antenna, so the actual position will not change, but of course the signals will get to the receiver a bit sooner. Dave, G8WRB ___ time-nuts mailing 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] I wish to shorten GPS antenna cable - should I let receiver find the position again?
I agree, used only for frequency reference you won't know the difference. Still, to join the rank of true time (not just frequency) nuts, you can configure the antenna cable delay! Many (all?) of the HP GPS-based smartclock units use the command :GPSYSTEM:REFERENCE:ADELAY to compensate for the antenna length delay. After changing cable length, configure it as shown on page 1-22 of http://www.leapsecond.com/museum/hp58503a/097-58503-12-iss-1.pdf Tim N3QE On Thu, Apr 23, 2015 at 8:03 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: I have an HP 58503A which I am using as a frequency source only - not to tell the time. I want to shorted the antenna cable a bit, but are wondering if I should let the GPS receiver finds it position again. Or either of the following better * Remove antenna cable, put a new N plug on, and screw it back in with the receiver kept powered up all the time. * Power off GPS receiver and power it back on with the cable connected. I'm not moving the antenna, so the actual position will not change, but of course the signals will get to the receiver a bit sooner. Dave, G8WRB ___ time-nuts mailing 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] Leica AT-303
The L1 only antenna that did very well was an AeroAntenna AT575-75W-TNCF-000-RG-26-NM Also a Racal LandStar MK4 did well. These are both small L1 only survey antennas. All my L1/L2 antennas are choke ring survey/geodetic grade devices... an equivalent choke ring L1 only antenna should perform just as well on a Tbolt... but I suspect very few people bother to make such a device. -- Which of the L1-only antennas did well? And do you have an explanation why the L1/L2 antennas did better, even for the L1-only reception case? ___ time-nuts mailing 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] I wish to shorten GPS antenna cable - should I let receiver find the position again?
On Thu, Apr 23, 2015 at 5:03 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: I have an HP 58503A which I am using as a frequency source only - not to tell the time. I want to shorted the antenna cable a bit, but are wondering if I should let the GPS receiver finds it position again. Or either of the following better * Remove antenna cable, put a new N plug on, and screw it back in with the receiver kept powered up all the time. * Power off GPS receiver and power it back on with the cable connected. I'm not moving the antenna, so the actual position will not change, but of course the signals will get to the receiver a bit sooner. If the goal is minimizing downtime and duration of degraded quality output, I would go with the former. The 58503A will enter holdover mode. It will keep its oven warm and retain its learned oscillator model parameters. When you reconnect the antenna it will pick right back up where it left off, with minimal settling time. Henry ___ time-nuts mailing 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] HP5328A HP5328B option 040
From your comments, it seems that finding a voltmeter board to add to my 5328A isn't worth the trouble. I have been looking for one even though I have plenty of voltmeters. I assume the option allows measurement of the signal inputs but still probably isn't worth all the agony of changing the panel, etc. Am I making sense? Bob K6DDX On Thursday, April 23, 2015 12:48 PM, Richard (Rick) Karlquist rich...@karlquist.com wrote: On 4/23/2015 12:20 AM, VK2DAP wrote: Dear time-nuts, I have a question about the HP5328A and HP5328B universal counters. 1) Generally speaking, would it be correct to say that when a product model number changes from A to B, that represents an improvement or major update to a product? 2) I am interested in the delay option that is mentioned in the user manual for the HP5328A (option 040). My question is simple. Why does this option not feature in the HP5328B, but only as option 040 on the HP5328A? Now you have asked a very interesting question. Since you are new to time-nuts, you probably don't know I worked for HP/Agilent/Keysight for 35 years. It would be a gross oversimplification to assume that an A/B change is an improvement, although in some cases that may be true. Often it has more to do with certain parts becoming unavailable. You should also know that there is typically a 5 year support life after the product goes out of production. It is very common that they will increment the suffix to get the 5 year clock running so they no longer have to support very old instruments. This was certainly the case with the 5061B cesium standard. The nixie displays were unobtainium and we couldn't support the 5061A because of this. I don't know specifically about the 5328A vs B. However, I was the project manager for the 5334B counter. The way that came about was that I just happened to notice that there were various design aspects of the 5334A that wasted a lot of money. I didn't work in the counters section at the time, but nevertheless I annoyed the RD manager by pointing out these money leaks. I guess he got tired of hearing me complain and one day he offered my the job of project manager on a 5334B model. We needed to reduce cost because we were losing military contracts to Racal-Dana. I changed certain design details in the B model where I could save money. The idea was to simply keep the performance the same and not add features. There were many things I inherited from the A model that I left alone if I couldn't reduce the cost. We were also on a very tight schedule. This prevented me from replacing the 4 separate microprocessors in the 34A with a single one. (Very long story as to why this was) Now to get to your question about why a feature in the A version would not carry through to the B version. The 5334A had an option of a digital voltmeter, which was put in essentially because we could, but then justified after the fact by claiming that customers wanted it because some of them ordered the option. I never thought this made sense and used my authority as 5334B project manager to get rid of it in the 5334B. Since HP also sold voltmeters, they could always buy a voltmeter from our voltmeter division. There are a bunch of reasons why the 5328B would lose a feature that the 5328A had, but the point is that this doesn't break any rule. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP5328A HP5328B
On Thu, Apr 23, 2015 at 9:13 PM, Charles Steinmetz csteinm...@yandex.com wrote: Magnus wrote: Would be fun to have a GPIB interface in the HP5328A ??? I have 6 or 7 of these, and they all have HPIB interfaces. It was option 011 for the 5328A. I believe all 5328Bs had HPIB as standard. Here is a link to the 5328A Opt 011 op/service manual: http://www.keysight.com/main/redirector.jspx?action=refcname=EDITORIALckey=805967lc=engcc=USnfr=-536900193.536897943.00 I'm not sure I've ever seen a 5328 (A or B) that didn't have HPIB. (It may be worth noting that ex-US military 5328As are very common here in the US, and I believe all of those had HPIB.) The ex-military counters have a number of differences from the commercial versions. 5328A without HPIB indeed do exist. I've seen a few of them, these are the no-options instruments usually. Frank IZ8DWF ___ time-nuts mailing 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] HP5328A HP5328B option 040
Dear time-nuts, I have a question about the HP5328A and HP5328B universal counters. 1) Generally speaking, would it be correct to say that when a product model number changes from A to B, that represents an improvement or major update to a product? 2) I am interested in the delay option that is mentioned in the user manual for the HP5328A (option 040). My question is simple. Why does this option not feature in the HP5328B, but only as option 040 on the HP5328A? My first post on the time-nuts forum. I'm sorry if this question has previously been addressed. I made a search but was unable to find an answer. Regards, Nick Sent from my iPad ___ time-nuts mailing 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] Leica AT-303
At least with a Tbolt, they do help... and quite a bit. When I was writing Lady Heather's precision survey code I tested it with several antennas (comparing the results to a cm level L1/L2 survey). The Leica antenna and a couple of other survey grade/choke ring antennas were, by far, the best (results with a foot or so). Cheap patch antennas were the worst (with maybe 5 foot errors). Some small L1 only survey grade antennas did pretty well... a couple of feet. They are about 6 inches in diameter and and inch thick and very light. I use one as my standard antenna. --- It’s not real clear that they have a significant advantage for L1 only operation with a Z3801. ___ time-nuts mailing 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] Signal/Phase noise analyzer
Thank you all for your reply's! It is for personal use, not a business. The budget it is very tight. I guess I can't find anything less that 2000-3000 euros even a second hand or a refurbished model. The main problem is that I'm starting from scratch... I found http://www.anapico.com/index.php/products/phase-noise-test-systems and the cheapest model (apph6000-is400) fits my needs (-160 dBc @ 100 Hz it is low enough) but it is too expensive (an outrageous of 18000 euros!). Their advantage, as in others, is to be a self contained analyzer with internal references. I don't know the price range of the Holzworth analyzer's but surely they are affordable compared with the one above. The model HA7402B needs two tunable LO, which I don't have, so a lot of investment has to be done. I can consider any setup as long as the above requirements are fulfilled and it is an affordable solution otherwise I've to wait for gather enough funds for this kind of investment. Regards, Vasco Soares - Original Message - From: Bob Camp kb...@n1k.org To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, April 22, 2015 11:36 PM Subject: Re: [time-nuts] Signal/Phase noise analyzer Hi Is this for a business or for a basement? Basement Are you looking for new self contained gear or combinations of used gear? Is a cross comparison device ok or do you need a stand alone device? How low do you need to go how fast? Is -190 dbc/ Hz low enough? Is a 24 hour run to long? Lots of variables…. Bob On Apr 22, 2015, at 10:07 AM, Vasco Soares vesoa...@deea.isel.ipl.pt wrote: Hi All, I'm searching for the less expensive signal analyzer to perform phase noise measurements on OCXO's. There is no need to go above 400 MHz - 1 GHz. I'm particularly interested on low frequency offset and good close in phase noise specs. Any recommendations? Best regards, Vasco Soares ___ time-nuts mailing 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] Tuning a Trimble Thunderbolt
On Thu, Apr 23, 2015 at 12:33 AM, Bob Camp kb...@n1k.org wrote: Hi Looking at that screen shot, something is *very* wrong with your GPS reception. Your GPS is 10X worse than it should be. You're right. The interference from the nearby Oncore UT+ seems to have been the problem. Since I moved the antennas further apart the signal strength for satellites in view of the Tbolt is 35-45 dBc and it can routinely view 6-7 satellites simultaneously -- this is essentially the same performance as when the Oncore is powered off and the antenna removed, so I'm happy. After moving the antennas further apart and doing a standard 2000-point site survey the 100-200ns phase offset spikes that occurred when satellites were added/removed from the solution dropped to 5-10ns. The oscillator offset also decreased. I'm now doing a longer precision survey to hopefully smooth those out more and get a better average position over a few satellite orbits. I would bet that the amp on the “Oncore” antenna is oscillating. It may do it intermittently. The frequency may swing back and forth through the GPS band. It may be the source of your GPS problem. Interesting. I have a second identical Oncore UT+ and antenna and will do some more tests to see if one of them is just being noisy, if it's a fault of the Oncore module itself, or the antenna. Many thanks to everyone on the list for the insight and assistance. Cheers! -Pete -- Pete Stephenson ___ time-nuts mailing 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] Tuning a Trimble Thunderbolt
On Thu, Apr 23, 2015 at 3:16 AM, Arthur Dent golgarfrinc...@gmail.com wrote: wb6bnq wrote: “I am a little confused. In your screen shot the overdetermined clock says you are at precisely 46.00 North by 7.0 East at 547 Meters.” I think I have the answer. I know when I was selling Tbolts I would PhotoShop out every digit after the decimal point so the displayed JPEG wouldn’t show my location. If Lat. was exactly 46.00 then it would show that, not just 46.(blank). Precisely. My apologies for the confusion: perhaps I shouldn't have used a black rectangle on a black background to obfuscate the location. The reported altitude at my location (which is just a few km outside downtown Bern) is plausible. After additional surveys it shows as being closer to 620m. Cheers! -Pete -- Pete Stephenson ___ time-nuts mailing 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] HP5328A HP5328B option 040
If anyone has a burning desire for a HP5328 with a volt meter module (and a GPIB board) please contact me off list. Regards Mark Spencer Sent from my iPad On 2015-04-23, at 3:18 PM, Bob Albert via time-nuts time-nuts@febo.com wrote: From your comments, it seems that finding a voltmeter board to add to my 5328A isn't worth the trouble. I have been looking for one even though I have plenty of voltmeters. I assume the option allows measurement of the signal inputs but still probably isn't worth all the agony of changing the panel, etc. Am I making sense? Bob K6DDX On Thursday, April 23, 2015 12:48 PM, Richard (Rick) Karlquist rich...@karlquist.com wrote: On 4/23/2015 12:20 AM, VK2DAP wrote: Dear time-nuts, I have a question about the HP5328A and HP5328B universal counters. 1) Generally speaking, would it be correct to say that when a product model number changes from A to B, that represents an improvement or major update to a product? 2) I am interested in the delay option that is mentioned in the user manual for the HP5328A (option 040). My question is simple. Why does this option not feature in the HP5328B, but only as option 040 on the HP5328A? Now you have asked a very interesting question. Since you are new to time-nuts, you probably don't know I worked for HP/Agilent/Keysight for 35 years. It would be a gross oversimplification to assume that an A/B change is an improvement, although in some cases that may be true. Often it has more to do with certain parts becoming unavailable. You should also know that there is typically a 5 year support life after the product goes out of production. It is very common that they will increment the suffix to get the 5 year clock running so they no longer have to support very old instruments. This was certainly the case with the 5061B cesium standard. The nixie displays were unobtainium and we couldn't support the 5061A because of this. I don't know specifically about the 5328A vs B. However, I was the project manager for the 5334B counter. The way that came about was that I just happened to notice that there were various design aspects of the 5334A that wasted a lot of money. I didn't work in the counters section at the time, but nevertheless I annoyed the RD manager by pointing out these money leaks. I guess he got tired of hearing me complain and one day he offered my the job of project manager on a 5334B model. We needed to reduce cost because we were losing military contracts to Racal-Dana. I changed certain design details in the B model where I could save money. The idea was to simply keep the performance the same and not add features. There were many things I inherited from the A model that I left alone if I couldn't reduce the cost. We were also on a very tight schedule. This prevented me from replacing the 4 separate microprocessors in the 34A with a single one. (Very long story as to why this was) Now to get to your question about why a feature in the A version would not carry through to the B version. The 5334A had an option of a digital voltmeter, which was put in essentially because we could, but then justified after the fact by claiming that customers wanted it because some of them ordered the option. I never thought this made sense and used my authority as 5334B project manager to get rid of it in the 5334B. Since HP also sold voltmeters, they could always buy a voltmeter from our voltmeter division. There are a bunch of reasons why the 5328B would lose a feature that the 5328A had, but the point is that this doesn't break any rule. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] HP5328A HP5328B option 040
On 04/23/2015 06:18 PM, Bob Albert via time-nuts wrote: From your comments, it seems that finding a voltmeter board to add to my 5328A isn't worth the trouble. I have been looking for one even though I have plenty of voltmeters. I assume the option allows measurement of the signal inputs but still probably isn't worth all the agony of changing the panel, etc. Am I making sense? Bob K6DDX To throw in my $0.02 worth: I have the DVM option on a couple of my counters, but never pay much attention to it. I have DMMs and a couple of Simpson 260s. However, the discussion made me curious so I checked on what they do. Two things of interest: - They only measure DC. (The ones I have). - The one in the 5328A will also Read A or Read B. This reads the level of the trigger voltage (DC). The catalog says this is really helpful for setup. I'll have to give it a try sometime. - Others are just a separate input and don't measure anything on the AC input signal. On the topic of suffix letters: Sometimes the suffix letter indicates a variation in the basic model. For example, the 3336 synthesizer/level generator: - 3336A - CCITT version - 3336B - Bell system version - 3336C - General purpose version. Gary ___ time-nuts mailing 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] Tuning a Trimble Thunderbolt
Bob from the screenshot what is it that shows the GPS reception as very wrong. just curious. -=Bryan=- From: kb...@n1k.org Date: Wed, 22 Apr 2015 18:33:09 -0400 To: time-nuts@febo.com Subject: Re: [time-nuts] Tuning a Trimble Thunderbolt Hi Looking at that screen shot, something is *very* wrong with your GPS reception. Your GPS is 10X worse than it should be. On Apr 22, 2015, at 9:37 AM, Pete Stephenson p...@heypete.com wrote: On Wed, Apr 22, 2015 at 1:47 PM, Bob Camp kb...@n1k.org wrote: Hi Backing up a bit to “getting a TBolt running”. 1) instal Lady Heather and get it connected to the TBolt 2) does it fire up and find any sats? Yes. It had been working consistently for several days prior to my first message. 3) are the power supplies holding regulation? Yes. 4) nail down the antenna in the best fixed location you can find Done. 5) run the auto-calibration feature in LH Done. This changed the gain from -5.0Hz/V to -3.132Hz/V and changed the initial voltage to 0.347V. I switched the time constant and damping values back to their defaults of 100 seconds and 1.200, respectively. 6) run a 48 hour survey with LH and write the location to ee memory Done. The location matches the averaged location surveyed from my Motorola Oncore UT+ (the antenna for which was about 10cm away from that for the Tbolt, some no-name mushroom-type antenna) and a handheld Garmin eTrex 20 (with GPS+GLONASS+WAAS) within a few meters. It also matches with Google Maps. In the attached screenshot you can clearly see the field of view from the antenna's current location over the last ~20 hours. Interestingly, the Oncore antenna (a cheap patch antenna from eBay) seems to be causing some intermittent issues with the Tbolt: if the antennas are too close there appears to be some sort of interference emitted by the Oncore antenna that makes it difficult for the Tbolt to lock onto the GPS signal and the Tbolt goes into holdover. Oddly, this is not consistent: the Tbolt and Oncore had coexisted for a few days with no problems but today some of the problems started up again. I would bet that the amp on the “Oncore” antenna is oscillating. It may do it intermittently. The frequency may swing back and forth through the GPS band. It may be the source of your GPS problem. Bob The same issue occured if the Oncore antenna was too close to my Garmin GPS 18x LVC. I have since moved the Oncore antenna further away (it's now about 50cm) and signal reception for the Tbolt is much better. Weird, but distance seems to resolve the issue, so not really a problem anymore. 7) Then check the EFC voltage, it should be fairly close to 0V, and not over 2.5 If you are 2.5, that’s probably a broken unit. Doesn't seem to be a problem. 8) Now start watching the EFC voltage for a few days and see that it’s leveling out and not spiking. Again spikes = something broke. See the attached screenshot. There's a few small EFC voltage spikes when the unit enters or leaves holdover, but otherwise it seems reasonably smooth in my (admittedly untrained) view. Until that’s all done, I would not dig to deep into the workings of the gizmo. It needs to be set up first. Other than the intermittent issues with the Oncore antenna, everything seems to be working reasonably well -- there's no obvious failures that I can spot. Cheers! -Pete Bob On Apr 21, 2015, at 4:30 AM, Pete Stephenson p...@heypete.com wrote: On Tue, Apr 21, 2015 at 4:25 AM, Charles Steinmetz csteinm...@yandex.com wrote: Pete wrote: On a related note, is it possible to extract any data regarding the training from the unit? Not as far as the time-nuts community knows, no (other than looking at the DAC voltage and temperature reporting during holdover and attempting to reverse engineer the prediction algorithm by correlating those with the long-term DAC voltage -- good luck). Finishing my PhD is enough work already. I don't think I'll try reverse-engineering the prediction algorithm quite yet. Perhaps later in my Copious Free Time(tm)? Are the training parameters saved periodically to non-volatile memory, or are they purely stored in RAM and so will be lost if powered down? If the latter, does the RAM have any provisions for backup power I doubt it -- mine always act as if they are training from zero if they have been powered down. Because of the lack of precise retrace of quartz crystals, I don't think you'd want old (pre-power-down) data, anyway. Some crystals will even come up drifting in the opposite direction after being powered down, and they all take some time (days, at least) to settle down after any disturbance (including power interruptions, however brief). Ok. It'd be nice if there was some way to keep the crystal
