Re: [time-nuts] Neat little cesium box
Greg, the only power source I am aware off that can provide the ~5W power required by that Novus box for 10-12 years with 20lbs weight limit without any external power sources or maintenance is a radioisotope thermoelectric generator (RTG) such as those used on Spacecraft. The Russians used to use those also in light houses. Maybe the atomic decay could be counted and used for improving timing some how?! That said the radiation would probably have a very negative effect on any electronics near it for long-term stability. I would also not call that solution disposable anywhere on earth. Definitely not hobby level stuff.. bye, Said In a message dated 6/13/2013 17:15:45 Pacific Daylight Time, engineer...@mt.net writes: Tom, Thank you for your concern. I unfortunately cannot disclose many details about the proposed project only to say that the application transcends much of the typical Time-Nuts areas of normality. At present we are evaluating typical frequency references to see if they will fit into this project. What I can say is that phase noise is of little interest but log-term frequency drift is. The completed unit will unfortunately not see GPS signals during most of its lifetime, be constrained to a weight not exceeding 20 lbs, be considered non-recoverable (disposable) due to areas of deployment thereby require a relatively cost-conscious design, have no access to a source of power let alone any natural power-producing resources and have an expected lifetime of 10-12 years without maintenance access. Most of the problems have been solved including the power source. This is not your typical kitchen table project. And, as new frequency references are developed and the design feasibility phase is still open, small and minimal power-consuming products such as the Novus unit will garner our attention. Thanks for your offer, Greg ___ time-nuts mailing 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] Neat little cesium box
Sounds like a space based systemPerhaps those mining probes Sent from my iPhone On Jun 14, 2013, at 2:11 AM, saidj...@aol.com wrote: Greg, the only power source I am aware off that can provide the ~5W power required by that Novus box for 10-12 years with 20lbs weight limit without any external power sources or maintenance is a radioisotope thermoelectric generator (RTG) such as those used on Spacecraft. The Russians used to use those also in light houses. Maybe the atomic decay could be counted and used for improving timing some how?! That said the radiation would probably have a very negative effect on any electronics near it for long-term stability. I would also not call that solution disposable anywhere on earth. Definitely not hobby level stuff.. bye, Said In a message dated 6/13/2013 17:15:45 Pacific Daylight Time, engineer...@mt.net writes: Tom, Thank you for your concern. I unfortunately cannot disclose many details about the proposed project only to say that the application transcends much of the typical Time-Nuts areas of normality. At present we are evaluating typical frequency references to see if they will fit into this project. What I can say is that phase noise is of little interest but log-term frequency drift is. The completed unit will unfortunately not see GPS signals during most of its lifetime, be constrained to a weight not exceeding 20 lbs, be considered non-recoverable (disposable) due to areas of deployment thereby require a relatively cost-conscious design, have no access to a source of power let alone any natural power-producing resources and have an expected lifetime of 10-12 years without maintenance access. Most of the problems have been solved including the power source. This is not your typical kitchen table project. And, as new frequency references are developed and the design feasibility phase is still open, small and minimal power-consuming products such as the Novus unit will garner our attention. Thanks for your offer, Greg ___ time-nuts mailing 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] Neat little cesium box
On Thu, 13 Jun 2013 18:15:25 -0600 Gregory Muir engineer...@mt.net wrote: Most of the problems have been solved including the power source. This is not your typical kitchen table project. And, as new frequency references are developed and the design feasibility phase is still open, small and minimal power-consuming products such as the Novus unit will garner our attention. If you are weight limited, then i'd use the CSAC directly instead of a packaged version like the Novus box. You will save quite a bit. You also want to temperature stabilize it, as this will probably be the major source for long term instability. After that comes probably the frequency wander of its small Cs vapor cell. Alternatively, look for a supplier of a Rb vapor cell that uses coherent population trapping (CPT) for interrogation instead of the standard microwave cavity vapor cells. These should be smaller and a bit more stable. But i don't think they have been around long enough for reliable long term data (at least i'm not aware of any). Also, it might be worth checking out spectratime, who are building the hydrogen masers for the Galileo satelites. Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing 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] Spectracom 8170 Time of Day grief...
I thought the Junghans Mega clock used DCF-77 rather than WWVB? Regards, David Partridge -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: 13 June 2013 22:27 To: time-nuts@febo.com Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief... I have four 15 year old Junghans Mega clocks through out the house. Ten days ago I noticed one of them dead. Battery, and by the look of the battery dead at least a month. I inserted a new battery and it did set. I did not watch it but today I went with one of them through the house and all are exact within a second. Even advance the second as close as I am able to observe. I am confident they synch daily. Bert Kehren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
On 14 June 2013 05:48, Perry Sandeen sandee...@yahoo.com wrote: There are two long standing truths about electronic equipment. One you can’t have too much filter capacitance. Two, you can’t cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier Well, I have to disagree with both comments. More filter capacitance in a standard linear power supply means the diodes take more current for a longer period of time. For any given diode, that puts more strain on it. At very high levels of capacitance, the amount of stored energy is huge, and can be dangerous. In the event of a fault, higher stored energy has the potential to do more damage than lower stored energy. Once you have sufficient capacitance, which includes calculating the effects of reduced supply voltage, minimum capacitance of device with tolerances, and some safety factor, I don't see what more capacitance does other than increase costs, weight, and the potential for more damage in the event of a fault. Whilst it is well known that increasing temperature gives rise to shorter component lifetimes, more cooling also requires more noise, and so a compromise has to be met. I have here an Air Control Industries VBL9 blower, which I want to sell in fact. That will move about 1000 cfm at 6 of water pressure. It happens to take 2.8 kW from the mains, the startup current is too large to not blow a normal mains fuse in a plug here in the UK, and the noise is enough to get neighbours wondering what the hell it is, despite I live in a detached house, some 50 m from the nearest property. So while a HP 5370B needs far more cooling than provided, I think the VBL9 would certainly provide too much cooling air. Engineering is always a compromise. HP usually got that balance about right, although in some instances, like the 5370B, that is not true. I know mine got pretty damm hot, and I'm quite near sea level. I would imagine for someone at a high altitude, it would be even worst. I have to agree with you about the serviceability of older HP equipment though. It is much more serviceable than modern equipment. However, you would have to go back a long way before finding equipment which one could guarantee one could keep going, as most things I'd contemplate buying will have a ASIC and/or some other specialist component which if it failed would be impossible to get except by taking one from a similar piece of equipment. Dave ___ time-nuts mailing 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] Spectracom 8170 Time of Day grief...
In the nineties Junghans decided to introduce their products in the US. Three products, a watch with stainless steel case and dial and LCD display, antenna in the leather band, a Mega with 5 inch dial and LCD display and a Mega with LCD only display. As part of the development effort they did a series of tests through out the US on signal strength. Miami was one of those locations. Since I knew senior management of their than parent company I was asked to help with the logistics. I arranges beachfront accommodations on Sunny Isles for a week and played tour guide. The result was that I ended up with two each of the three products. As I posted before they all work fine and one had a very bad battery, most likely out of service for a month and after inserting a new battery it synchronized. Bert Kehren Miami In a message dated 6/14/2013 5:25:45 A.M. Eastern Daylight Time, david.partri...@perdrix.co.uk writes: I thought the Junghans Mega clock used DCF-77 rather than WWVB? Regards, David Partridge -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: 13 June 2013 22:27 To: time-nuts@febo.com Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief... I have four 15 year old Junghans Mega clocks through out the house. Ten days ago I noticed one of them dead. Battery, and by the look of the battery dead at least a month. I inserted a new battery and it did set. I did not watch it but today I went with one of them through the house and all are exact within a second. Even advance the second as close as I am able to observe. I am confident they synch daily. Bert Kehren ___ time-nuts mailing 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] VE2ZAZ controller
Bob I agree the comment was on the 3586 mod not the gpsdo. As I recall Bert would send a programed proc. I bought one from him for not much. Regards Paul WB8TSL On Fri, Jun 14, 2013 at 1:03 AM, Bob Stewart b...@evoria.net wrote: Perry, Could you give me some context for your post? Is this related to my post about building a GPSDO, or is this something else? It looks like Bert did something specifically for the 3586. That is not what I was posting about. Bob - Original Message - From: Perry Sandeen sandee...@yahoo.com To: time-nuts@febo.com time-nuts@febo.com Cc: Sent: Thursday, June 13, 2013 11:40 PM Subject: [time-nuts] VE2ZAZ controller List, The VE2ZAZ is a very clever design, but its design limits its usefulness to many of us. First, one has to be able to program a microprocessor. This is a non-starter for many of us. Secondly you have to have a different program depending on which 3586 one has or sub-set thereof. If you have more than one working 3586 as I do, things can be complicated quickly. IIRC there are six possible frequencies. ___ time-nuts mailing 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] Spectracom 8170 Time of Day grief...
I thought the Junghans Mega clock used DCF-77 rather than WWVB? Regards, David Partridge There are a number of different models of Junghans Mega clocks, from desk clocks to wristwatches. The ones sold for the USA market receive WWVB. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Talking of Cooling HP 5370's, I have a 12V fan Gorilla taped to mine fed from a wallwart. Not elegant, but it has reduced the heat sink temperature dramatically. Is anyone else concerned about the heat sink temperature on the 5370? Has anyone done a fan modification they would care to share? Also, my 8566A RF section pass transistor heat sink gets awfully warm too, does anyone have a sensible solution? -marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David Kirkby Sent: Friday, 14 June 2013 7:14 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP and other equipment failure On 14 June 2013 05:48, Perry Sandeen sandee...@yahoo.com wrote: There are two long standing truths about electronic equipment. One you can't have too much filter capacitance. Two, you can't cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier Well, I have to disagree with both comments. More filter capacitance in a standard linear power supply means the diodes take more current for a longer period of time. For any given diode, that puts more strain on it. At very high levels of capacitance, the amount of stored energy is huge, and can be dangerous. In the event of a fault, higher stored energy has the potential to do more damage than lower stored energy. Once you have sufficient capacitance, which includes calculating the effects of reduced supply voltage, minimum capacitance of device with tolerances, and some safety factor, I don't see what more capacitance does other than increase costs, weight, and the potential for more damage in the event of a fault. Whilst it is well known that increasing temperature gives rise to shorter component lifetimes, more cooling also requires more noise, and so a compromise has to be met. I have here an Air Control Industries VBL9 blower, which I want to sell in fact. That will move about 1000 cfm at 6 of water pressure. It happens to take 2.8 kW from the mains, the startup current is too large to not blow a normal mains fuse in a plug here in the UK, and the noise is enough to get neighbours wondering what the hell it is, despite I live in a detached house, some 50 m from the nearest property. So while a HP 5370B needs far more cooling than provided, I think the VBL9 would certainly provide too much cooling air. Engineering is always a compromise. HP usually got that balance about right, although in some instances, like the 5370B, that is not true. I know mine got pretty damm hot, and I'm quite near sea level. I would imagine for someone at a high altitude, it would be even worst. I have to agree with you about the serviceability of older HP equipment though. It is much more serviceable than modern equipment. However, you would have to go back a long way before finding equipment which one could guarantee one could keep going, as most things I'd contemplate buying will have a ASIC and/or some other specialist component which if it failed would be impossible to get except by taking one from a similar piece of equipment. Dave ___ time-nuts mailing 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] New to list and GPSDO questions
I like that explanation. I think I get it. I don't think it is likely to cause me any worry. My actual measurement of ADEV on my VE2ZAZ device gave me a 100,000s sigma of just under 1E-10 and that works for me (best is at 1000s, 4E-11). Maybe the strength and the danger of the VE2ZAZ design is the wide range of integration settings. If I were to pick some very unfortunate settings, maybe it would degrade overall performance in the way you describe. Thanks for taking the time to explain it to me. Chris On 6/13/2013 10:15 PM, Richard H McCorkle wrote: Chis, Over time without phase correction the analogy would be more like zig to the right, correct to go straight, zig to the right, correct again, and keep repeating this sequence ad infinium as the source ages in predominantly one direction. Each time the phase shifts in the same direction and before long you are on a different road a full clock cycle to the right and continuing to shift in the same direction. The total number of clocks over the period has changed from the ideal even though the average frequency has been correct. So over the short-term the right number of cycles occur, but over the long term there is an increasing error from the ideal number of clock cycles as the period increases. If all you need is a frequency that is stable over short periods then the phase is of no concern. But when using a scope or TIC to compare a device under test (DUT) to the reference to determine its Adev over longer periods then you need the phase of the reference to be constant over the maximum measurement period (typically 4-5 days for a 1-day Adev value) to determine the DUT long-term drift. By keeping track of the total accumulated count from an arbitrary starting point (i.e. when the reference sample is taken) and adding 6800 HEX each update the reference count would represent the ideal count after X updates if no drift had occurred. Comparing the current count to this ideal gives the total change since the arbitrary reference was first stored. By adding steering to keep the actual sample count at the ideal value then over the long-term there would be no drift as it would be corrected out. The actual phase to GPS isn't the important factor - the change in the phase over long periods (like a day or week) is as it represents an error in the total number of counts over that period and a reduction in the long-term stability. Richard I'm with Bob in that I don't really understand this description. And what are we trying to be in phase with? the 1PPS? Is it possible to reproduce the actual phase of the clock in the GPS birds once it has been through my GPS and come out as 1PPS? I picture the EFC steering the car straight down the road. And you want to adjust not just the drift to the right but steer back to the center of the lane. I think I get that part. I don't get who is setting the lane and why I should care. Do the statistics (ADEV, etc.) show that this is an improvement? If I'm doing my slow zigzag down the center line or the right shoulder, again, do I care? Chris w0ep ___ time-nuts mailing 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] Spectracom 8170 Time of Day grief...(WWVB Clock)
Well, it 'killed' my two. The website for the manufacturer of mine (both SkyScan, cheap from Sam's) stated that there was a problem with WWVB. I'll keep an eye out for a replacement. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles P. Steinmetz Sent: Thursday, June 13, 2013 6:03 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief...(WWVB Clock) Joe wrote: In a slightly different direction, are there any commercially available 'PSK Compliant Atomic Clocks' out there for those of us used to looking at the 'correct time'? Also, what, exactly, was the advantage of changing modulation formats? That 'killed' all the existing 'Atomic Clocks'? No, it killed phase-locking instruments, including the Spectracom clocks. Most atomic clocks designed for time-of-day use do not, and never did, phase lock to the WWVB carrier. My 20-year-old Brookstone atomic clock still works just as it always did (within tens of mS AFAICT). So should most other older atomic clocks, and everything currently available from the many time-of-day atomic clock suppliers. 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. ___ time-nuts mailing 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] Spectracom 8170 Time of Day grief...(WWVB Clock)
I did call spectracom just to see if they had any parts for the 81XX series. They said they had not had any for 10 years. The Guy was helpful. But those magical 60Khz xtals aren't to be had. Regards Paul WB8TSL On Fri, Jun 14, 2013 at 10:37 AM, J. L. Trantham jlt...@att.net wrote: Well, it 'killed' my two. The website for the manufacturer of mine (both SkyScan, cheap from Sam's) stated that there was a problem with WWVB. I'll keep an eye out for a replacement. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles P. Steinmetz Sent: Thursday, June 13, 2013 6:03 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief...(WWVB Clock) Joe wrote: In a slightly different direction, are there any commercially available 'PSK Compliant Atomic Clocks' out there for those of us used to looking at the 'correct time'? Also, what, exactly, was the advantage of changing modulation formats? That 'killed' all the existing 'Atomic Clocks'? No, it killed phase-locking instruments, including the Spectracom clocks. Most atomic clocks designed for time-of-day use do not, and never did, phase lock to the WWVB carrier. My 20-year-old Brookstone atomic clock still works just as it always did (within tens of mS AFAICT). So should most other older atomic clocks, and everything currently available from the many time-of-day atomic clock suppliers. 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. ___ time-nuts mailing 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] Fw: New to list and GPSDO questions
As you drive down the road it is important that you do not over correct errors and look ahead and start turning before the car reaches the turn, your corrections have a delay in taking effect as well as a delay in knowing where on the road you are. You know where the car was but more important is where it will be when your correction takes effect. Stanley - Original Message - From: Chris Howard ch...@elfpen.com To: mccor...@ptialaska.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, June 13, 2013 8:58 PM Subject: Re: [time-nuts] Fw: New to list and GPSDO questions I'm with Bob in that I don't really understand this description. And what are we trying to be in phase with? the 1PPS? Is it possible to reproduce the actual phase of the clock in the GPS birds once it has been through my GPS and come out as 1PPS? I picture the EFC steering the car straight down the road. And you want to adjust not just the drift to the right but steer back to the center of the lane. I think I get that part. I don't get who is setting the lane and why I should care. Do the statistics (ADEV, etc.) show that this is an improvement? If I'm doing my slow zigzag down the center line or the right shoulder, again, do I care? Chris w0ep On 6/13/2013 5:51 PM, Richard H McCorkle wrote: Hi Bob, The VE2ZAZ controller is a frequency locked loop that keeps the source on frequency but over time the phase drifts, as past corrections are not compensated for. When the system is stable every 16 seconds the 16-bit counter rolls over 2441 times with an extra 26624 counts (6800 HEX). The previous count is subtracted from the current count, the difference from 6800 HEX is used to update the EFC to correct the frequency, and the current count is stored as the previous count for the next sample. When the current difference is not exactly 6800 HEX then a phase shift of 6.25ns has occurred over the sample period for each count of the difference from 6800 HEX. The EFC corrects the frequency to give the proper 6800 HEX over the following samples, but the phase shift from the previous error during the correction period remains. If you add a little code to provide a correction history you can add phase correction to the VE2ZAZ controller as well. Once lock is established store the sample count as a phase reference count. Add 6800 HEX to the reference count every update and store the result as the next reference value. Use the difference between the current and previous samples from 6800 HEX to coarse correct the frequency as currently done, but add the difference between the current count and reference count to the EFC correction as a fine phase correction. If hold or unlock occurs disable the phase correction routine until lock is re-established. Then store a new reference and restart the phase correction process. By updating the reference every update it provides a phase history so the accumulated count error over time can be removed and the phase of the source can be stabilized. Richard Atilla, Isn't the VE2ZAZ circuit functionally equivalent to your example 3? Granted, he's not picking the 10 millionth transition and checking its phase difference to the reference, but I've only got a 1PPS reference with a 1uS or so jitter from pulse to pulse. Bert is averaging over 16 seconds, and creating a PWM signal to drive an integrator (simulating a DAC), which will drive a Trimble 34310-T. And like I mentioned earlier, I just like the way Bert did it. It has a kind of elegance that appeals to my inner hacker. =) Bob - AE6RV - Original Message - From: Attila Kinali att...@kinali.ch To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Cc: Sent: Thursday, June 13, 2013 3:39 PM Subject: Re: [time-nuts] New to list and GPSDO questions snip [3] Describes how to use a clock synchronizer to build a GPSDO. Probably not the easiest and not the cheapest way, but definitly one with a very low parts count. snip [3] The AD9548 as a GPS Disciplined Stratum 2 Clock, by Gentile, 2009 http://www.analog.com/static/imported-files/application_notes/AN-1002.pdf ___ time-nuts mailing 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] HP and other equipment failure
About the HP5370 please got o see my solution to: http://www.timeok.it/files/hp_5370a_temperature_solution.pdf Luciano timeok see : www.timeok.it On Fri, Jun 14, 2013 at 4:26 PM, Mark C. Stephens ma...@non-stop.com.auwrote: Talking of Cooling HP 5370's, I have a 12V fan Gorilla taped to mine fed from a wallwart. Not elegant, but it has reduced the heat sink temperature dramatically. Is anyone else concerned about the heat sink temperature on the 5370? Has anyone done a fan modification they would care to share? Also, my 8566A RF section pass transistor heat sink gets awfully warm too, does anyone have a sensible solution? -marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David Kirkby Sent: Friday, 14 June 2013 7:14 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP and other equipment failure On 14 June 2013 05:48, Perry Sandeen sandee...@yahoo.com wrote: There are two long standing truths about electronic equipment. One you can't have too much filter capacitance. Two, you can't cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier Well, I have to disagree with both comments. More filter capacitance in a standard linear power supply means the diodes take more current for a longer period of time. For any given diode, that puts more strain on it. At very high levels of capacitance, the amount of stored energy is huge, and can be dangerous. In the event of a fault, higher stored energy has the potential to do more damage than lower stored energy. Once you have sufficient capacitance, which includes calculating the effects of reduced supply voltage, minimum capacitance of device with tolerances, and some safety factor, I don't see what more capacitance does other than increase costs, weight, and the potential for more damage in the event of a fault. Whilst it is well known that increasing temperature gives rise to shorter component lifetimes, more cooling also requires more noise, and so a compromise has to be met. I have here an Air Control Industries VBL9 blower, which I want to sell in fact. That will move about 1000 cfm at 6 of water pressure. It happens to take 2.8 kW from the mains, the startup current is too large to not blow a normal mains fuse in a plug here in the UK, and the noise is enough to get neighbours wondering what the hell it is, despite I live in a detached house, some 50 m from the nearest property. So while a HP 5370B needs far more cooling than provided, I think the VBL9 would certainly provide too much cooling air. Engineering is always a compromise. HP usually got that balance about right, although in some instances, like the 5370B, that is not true. I know mine got pretty damm hot, and I'm quite near sea level. I would imagine for someone at a high altitude, it would be even worst. I have to agree with you about the serviceability of older HP equipment though. It is much more serviceable than modern equipment. However, you would have to go back a long way before finding equipment which one could guarantee one could keep going, as most things I'd contemplate buying will have a ASIC and/or some other specialist component which if it failed would be impossible to get except by taking one from a similar piece of equipment. Dave ___ time-nuts mailing 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. -- Luciano Timeok visit : www.timeok.it ___ time-nuts mailing 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] Spectracom 8170 Time of Day grief...
Joe, All of the SkyScan clocks I know of have failed. I have two of them that no longer work. However, I have two made by Junghan's that seem to be fine. Take a look at www.junghansUSA.com Burt Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief...(WWVB Clock) Well, it 'killed' my two. The website for the manufacturer of mine (both SkyScan, cheap from Sam's) stated that there was a problem with WWVB. I'll keep an eye out for a replacement. Joe Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing 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] Spectracom 8170 Time of Day grief...
Burt, I saw that earlier. I am hoping to find a wall clock. I wonder what it is about the SkyScan clock that makes them fail. I doubt they phase lock the signal but they might. I think all the data is AM modulated, IIRC. Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Burt I. Weiner Sent: Friday, June 14, 2013 10:55 AM To: time-nuts@febo.com Subject: [time-nuts] Spectracom 8170 Time of Day grief... Joe, All of the SkyScan clocks I know of have failed. I have two of them that no longer work. However, I have two made by Junghan's that seem to be fine. Take a look at www.junghansUSA.com Burt Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief...(WWVB Clock) Well, it 'killed' my two. The website for the manufacturer of mine (both SkyScan, cheap from Sam's) stated that there was a problem with WWVB. I'll keep an eye out for a replacement. Joe Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Re: HP5370B cooling. I currently have three HP5370B's that have been running for many months in a cool room (typical room temperature is under 20 degrees C even in the summer) so far without issues. Other than placing them away from other heat producing equipment and and double checking the ac line voltage supplied to them from a UPS system and the voltage setting of the power supply no special precautions were taken. In the winter they provide useful heat to an otherwise cool room in my basement. Your mileage may vary (: One trick I've used on other older equipment with linear power supplies is to reduce the AC line voltage (the exact voltage depends on the equipment in question) using a variac, to cut down on the power that the pass tranistors in the power supplies need to disipate. I've never bothered to do this with the HP5370B's but I be inclined to go down this road before I started blowing extra air over them with fans. In general I agree with the comments about the serviceability of the older HP gear. I'm hopefull that I can keep at least two of my four HP5370B's working for many years to come. Regards Mark Spencer -- Message: 1 Date: Fri, 14 Jun 2013 14:26:50 + From: Mark C. Stephens ma...@non-stop.com.au To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] HP and other equipment failure Message-ID: 6c1fe0e5a70c9640b597f869a899c017032f0...@tmpexch.non-stop.com.au Content-Type: text/plain; charset=us-ascii Talking of Cooling HP 5370's, I have a 12V fan Gorilla taped to mine fed from a wallwart. Not elegant, but it has reduced the heat sink temperature dramatically. Is anyone else concerned about the heat sink temperature on the 5370? Has anyone done a fan modification they would care to share? Also, my 8566A RF section pass transistor heat sink gets awfully warm too, does anyone have a sensible solution? -marki ___ time-nuts mailing 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] Spectracom 8170 Time of Day grief...
Hi The cheap La Crosse wall clocks seem to do fine with the new WWVB format. http://www.amazon.com/La-Crosse-Technology-WT-3128U-12-Inch/dp/B0039O6W88/ref=sr_1_16?ie=UTF8qid=1371230316sr=8-16keywords=la+crosse+clock Is one, there are an enormous number of different models. I suspect that they all use the same chips. Bob On Jun 14, 2013, at 12:05 PM, J. L. Trantham jlt...@att.net wrote: Burt, I saw that earlier. I am hoping to find a wall clock. I wonder what it is about the SkyScan clock that makes them fail. I doubt they phase lock the signal but they might. I think all the data is AM modulated, IIRC. Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Burt I. Weiner Sent: Friday, June 14, 2013 10:55 AM To: time-nuts@febo.com Subject: [time-nuts] Spectracom 8170 Time of Day grief... Joe, All of the SkyScan clocks I know of have failed. I have two of them that no longer work. However, I have two made by Junghan's that seem to be fine. Take a look at www.junghansUSA.com Burt Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief...(WWVB Clock) Well, it 'killed' my two. The website for the manufacturer of mine (both SkyScan, cheap from Sam's) stated that there was a problem with WWVB. I'll keep an eye out for a replacement. Joe Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing 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] HP and other equipment failure
Luciano wrote: About the HP5370 please got o see my solution The fans would cool the transistors better if they were blowing on the heatsink fins, not directly at the transistors. I use a slow fan that is large enough to blow over the whole heatsink assembly. You can't hear it over the noise of the internal fan, and the transistors run at 35C. 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.
[time-nuts] Looking for an old french disertation
Hi, I'm looking for an old french diseration, which doesn't seem to be available electronically (at least i couldn't find it anywhere) and none of the libraries in switzerland seem to have it. Unfortunately, the author died a year ago, so i cannot contact him directly anymore. If anyone has an idea where and how i could get a copy (in any form) of Mécanismes non linéaires dans les résonateurs à quartz: théorie, expériences et applications métrologiques par Jean-Jacques Gagnepain, 1972 I would really appreciate your help. Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing 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] Neat little cesium box
Most RTG sources use Plutonium 238 or Strontium 90. Primary decay component is Alpha particles which can be stopped dead by a few mm of shielding. Good article on Wikipedia: http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of saidj...@aol.com Sent: Friday, June 14, 2013 00:11 To: time-nuts@febo.com Subject: Re: [time-nuts] Neat little cesium box Greg, the only power source I am aware off that can provide the ~5W power required by that Novus box for 10-12 years with 20lbs weight limit without any external power sources or maintenance is a radioisotope thermoelectric generator (RTG) such as those used on Spacecraft. The Russians used to use those also in light houses. Maybe the atomic decay could be counted and used for improving timing some how?! That said the radiation would probably have a very negative effect on any electronics near it for long-term stability. I would also not call that solution disposable anywhere on earth. Definitely not hobby level stuff.. bye, Said In a message dated 6/13/2013 17:15:45 Pacific Daylight Time, engineer...@mt.net writes: Tom, Thank you for your concern. I unfortunately cannot disclose many details about the proposed project only to say that the application transcends much of the typical Time-Nuts areas of normality. At present we are evaluating typical frequency references to see if they will fit into this project. What I can say is that phase noise is of little interest but log-term frequency drift is. The completed unit will unfortunately not see GPS signals during most of its lifetime, be constrained to a weight not exceeding 20 lbs, be considered non-recoverable (disposable) due to areas of deployment thereby require a relatively cost-conscious design, have no access to a source of power let alone any natural power-producing resources and have an expected lifetime of 10-12 years without maintenance access. Most of the problems have been solved including the power source. This is not your typical kitchen table project. And, as new frequency references are developed and the design feasibility phase is still open, small and minimal power-consuming products such as the Novus unit will garner our attention. Thanks for your offer, Greg ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Looking for an old french disertation
Attila wrote: Hi, I'm looking for an old french diseration, which doesn't seem to be available electronically (at least i couldn't find it anywhere) and none of the libraries in switzerland seem to have it. Unfortunately, the author died a year ago, so i cannot contact him directly anymore. If anyone has an idea where and how i could get a copy (in any form) of Mécanismes non linéaires dans les résonateurs à quartz: théorie, expériences et applications métrologiques par Jean-Jacques Gagnepain, 1972 I would really appreciate your help. The best place to start is usually the library of the institution at which the dissertation was presented. If this was Mr. Gagnepain's PhD dissertation, his UFFC obituary indicates that he received his PhD from the University of Besançon in 1972. His early papers may be derived from the dissertation, including Non linear effects in piezoelectric quartz crystals (Physical Acoustics vol XI pp 245-288, Academic press 1975). John Vig listed many of Mr. Gagnepain's IEEE publications in an addendum to the UFFC obituary: http://www.ieee-uffc.org/frequency-control/memoria-gagnepain.asp 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] Looking for an old french disertation
Attila, a quick look at the système universitaire de documentation website list the university libraries where a paper copy is available for loan: http://www.sudoc.fr/008747431 (click on the Où trouver ce document? link at the top) : AIX-MARSEILLE 1 - BU Sci.St Charles BESANCON - BU Sciences Staps PARIS SUD Tg Besançon POITIERS - BU Sciences TOULOUSE 3 - BU Sciences Unfortunately, as far as I understood, you need to be a student at a French university for obtaining an interlibrary loan. The global French libraries catalog (http://ccfr.bnf.fr) does not list any additional (i.e. public) libraries where this is available. Hope this can help a little... regards, Claudio On 06/14/2013 08:12 PM, Attila Kinali wrote: Hi, I'm looking for an old french diseration, which doesn't seem to be available electronically (at least i couldn't find it anywhere) and none of the libraries in switzerland seem to have it. Unfortunately, the author died a year ago, so i cannot contact him directly anymore. If anyone has an idea where and how i could get a copy (in any form) of Mécanismes non linéaires dans les résonateurs à quartz: théorie, expériences et applications métrologiques par Jean-Jacques Gagnepain, 1972 I would really appreciate your help. Attila Kinali ___ time-nuts mailing 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] Thunderbolt GPS APP updates?
Current Thunderbolt GPS shows: APP: 2.2 11 Mar 2002 GPS: 10.2 14 Nov 2001 Mfg: 07 June 2002 I previously owned another APP:3.0 27 June 2002 GPS: 10.2 14 Nov 2001 Mfg: 21 Mar 2003 The two apparently were manufactured within 3 months of one another. Some questions: 1) What is APP and what does it do? 2) Would it be possible to put APP 3.0 on the current unit? If so would cause problems or provide any benefits? Regards Brian - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5911 - Release Date: 06/14/13 ___ time-nuts mailing 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] Thunderbolt GPS APP updates?
The two apparently were manufactured within 3 months of one another. I'd say 9 months. The firmware revision from 2.2 to 3.0 is the 3 months you mentioned and from what I could gather ( which may or may not be correct) mainly changed the algorithm for handling carryover and unless you're without a lock for a long time you'll not notice any real difference. I wouldn't worry about it. -Arthur ___ time-nuts mailing 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] Thunderbolt GPS APP updates?
Thanks. On 6/14/2013 23:22, Arthur Dent wrote: The two apparently were manufactured within 3 months of one another. I'd say 9 months. The firmware revision from 2.2 to 3.0 is the 3 months you mentioned and from what I could gather ( which may or may not be correct) mainly changed the algorithm for handling carryover and unless you're without a lock for a long time you'll not notice any real difference. I wouldn't worry about it. -Arthur - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5911 - Release Date: 06/14/13 ___ time-nuts mailing 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] Spectracom 8170 grief... Watching the problem...
Gang, I took a look at the WWVB signal using a 1:1 Lissajou signal the same way I do for the FMT's. Using a 10:1 scope probe I sampled off the output of the pre-amp in the 8170 and fed it into a HP-3586B tuned to 60 kHz and compared the resultant I.F. against a HP-3336A tuned to the 15625 I.F. Both the 3586B and the 3336A are GPS locked. I won't go into the nitty gritties of how I do this, but f anyone's interested they can see my FMT Methodology at: http://www.k5cm.com/k6OQK%20FMT%20NEW.htm What I saw was the phase of the WWVB signal shifting back and forth 180 Degrees coincident with the dips in the carrier. Coincidentally, this is what all of you have been telling me, but, just the same, it was interesting to watch. The duration of each shift obviously are a form of zeros, ones and place holder. I'm wondering if the code used to shift the phase is the same code as carried in the legacy system where the duration of the carrier dips corresponds to the ones and zeros, and the place holder. Burt, K6OQK Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Looking for an old french disertation
On 14 June 2013 20:24, Claudio Girardi claudio.gira...@virgilio.it wrote: Unfortunately, as far as I understood, you need to be a student at a French university for obtaining an interlibrary loan. The global French libraries catalog (http://ccfr.bnf.fr) does not list any additional (i.e. public) libraries where this is available. Hope this can help a little... regards, Claudio If all else fails, contacting the family would probably result in getting access to a copy. A spouse or sibling is likely to have a paper copy. It's not an ideal approach, but as a last resort, it may lead somewhere. Dave. ___ time-nuts mailing 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] Neat little cesium box
On 6/14/13 10:55 AM, DaveH wrote: Most RTG sources use Plutonium 238 or Strontium 90. Primary decay component is Alpha particles which can be stopped dead by a few mm of shielding. Good article on Wikipedia: http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator Dave but not ALL the radiation is alpha particles. It also generates some x rays (up to about 100keV and gammas (up to about 1 MeV). Sure, the fraction is very tiny, but when you have a lot of disintegrations/second, even a small percentage can add up (this is the problem with so-called aneutronic fusion reactions) ___ time-nuts mailing 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] Beaglebone NTP server
As an alternative to the Net4501, the AM335x in the Beaglebone has timers that accept an external clock up to 25 MHz (TCLKIN) and can timestamp events on an input pin (TIMER4-TIMER7). Both sets of pins are available on the headers after an appropriate pinmux configuration. I'm finishing the clocksource driver for Linux, I'm testing it using the 10 MHz and PPS outputs of a LEA-6T. ntpd loopstats show +/- 0.1 us offsets, frequency is a flat 0.000 PPM as expected. ___ time-nuts mailing 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] Spectracom 8170 grief... Watching the problem...
Burt Yes this has been looked at before by time-nuts and as you say it shifts. Its also documented by nist and unfortunately the AM code is nothing like the new psk code for a good reason. Better noise immunity and other things also documented. Its complex at least for me. Overall I get it but when I get to the error correction and disassembly of the message format its not so clear. Though perhaps it would be if I were building a psk decoder and that may happen later but only after the d-psk-r is really pretty complete. A by product of the d-psk-r is the psk code so its there for the taking. Regards Paul WB8TSL On Fri, Jun 14, 2013 at 8:13 PM, Burt I. Weiner b...@att.net wrote: Gang, I took a look at the WWVB signal using a 1:1 Lissajou signal the same way I do for the FMT's. Using a 10:1 scope probe I sampled off the output of the pre-amp in the 8170 and fed it into a HP-3586B tuned to 60 kHz and compared the resultant I.F. against a HP-3336A tuned to the 15625 I.F. Both the 3586B and the 3336A are GPS locked. I won't go into the nitty gritties of how I do this, but f anyone's interested they can see my FMT Methodology at: http://www.k5cm.com/k6OQK%**20FMT%20NEW.htmhttp://www.k5cm.com/k6OQK%20FMT%20NEW.htm What I saw was the phase of the WWVB signal shifting back and forth 180 Degrees coincident with the dips in the carrier. Coincidentally, this is what all of you have been telling me, but, just the same, it was interesting to watch. The duration of each shift obviously are a form of zeros, ones and place holder. I'm wondering if the code used to shift the phase is the same code as carried in the legacy system where the duration of the carrier dips corresponds to the ones and zeros, and the place holder. Burt, K6OQK Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] Spectracom 8170 grief... Watching the problem...
What I saw was the phase of the WWVB signal shifting back and forth 180 Degrees coincident with the dips in the carrier. Coincidentally, this is what all of you have been telling me, but, just the same, it was interesting to watch. The duration of each shift obviously are a form of zeros, ones and place holder. I'm wondering if the code used to shift the phase is the same code as carried in the legacy system where the duration of the carrier dips corresponds to the ones and zeros, and the place holder. Burt, K6OQK The new PM (phase modulated) WWVB format is *in addition* to the existing AM format. Consequently millions of commodity clocks and wrist watches continue to function just fine. The only instruments that break are vintage phase tracking receivers. Paul's Costas's loop project addresses those receivers. The latest preliminary version of the spec for the new PM code is here: http://www.nist.gov/pml/div688/grp40/upload/NIST-Enhanced-WWVB-Broadcast-Format-2012-12-07-3.pdf If anyone has seen a more recent version, let me know. 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.
Re: [time-nuts] Spectracom 8170 Time of Day grief...
More like what I'm looking for. Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Friday, June 14, 2013 12:21 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief... Hi The cheap La Crosse wall clocks seem to do fine with the new WWVB format. http://www.amazon.com/La-Crosse-Technology-WT-3128U-12-Inch/dp/B0039O6W88/re f=sr_1_16?ie=UTF8qid=1371230316sr=8-16keywords=la+crosse+clock Is one, there are an enormous number of different models. I suspect that they all use the same chips. Bob On Jun 14, 2013, at 12:05 PM, J. L. Trantham jlt...@att.net wrote: Burt, I saw that earlier. I am hoping to find a wall clock. I wonder what it is about the SkyScan clock that makes them fail. I doubt they phase lock the signal but they might. I think all the data is AM modulated, IIRC. Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Burt I. Weiner Sent: Friday, June 14, 2013 10:55 AM To: time-nuts@febo.com Subject: [time-nuts] Spectracom 8170 Time of Day grief... Joe, All of the SkyScan clocks I know of have failed. I have two of them that no longer work. However, I have two made by Junghan's that seem to be fine. Take a look at www.junghansUSA.com Burt Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief...(WWVB Clock) Well, it 'killed' my two. The website for the manufacturer of mine (both SkyScan, cheap from Sam's) stated that there was a problem with WWVB. I'll keep an eye out for a replacement. Joe Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing 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] Alternative WWVB Spectracom solution
Since the topic of WWVB came up again, here's another idea. A number of people still want to use (hp, or Tracor, or) Spectracom WWVB receivers as frequency standards or to maintain NIST traceability. As has been discussed on the list, these receivers no longer work now that the enhanced WWVB format is in effect 24/7. Paul Swed's Costas loop project is a nice hardware solution. I'm wondering if anyone wants to help on a mostly software solution. Here's the idea -- if you already know the time of day to a few milliseconds (from NTP, GPS, etc.) it should be simple to generate the live 1 baud data of the new PM code. The only hardware you need is an analog inverter/switch which then applies either a 0 or 180 degree shift to the antenna signal, based on the predicted state of the PM code for that second. In this case, every second, your local phase shifting neatly cancels the Ft Collins phase shifting. The PM bit prediction and edge timing don't have to be perfect, just close enough that the 60 kHz PLL stays happily locked. The advantage of this approach is that the existing WWVB phase tracking receiver can remain completely unmodified. You would simply insert the programmable inverter inline between the antenna and the receiver. For testing even a DPDT reed relay might do the job. It would be a good project for a RPi (running an NTP client) or an Arduino (using a cheap GPS NMEA+1PPS receiver). If you can spot holes in the design let me know. It seems too simple to be true. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Alternative WWVB Spectracom solution
The software already exists to do this. It is included with the standard NTP source code in a directory called (from memory) test. It was designed to test the time code clock driver. You are right it is not complex, you can read the code and see how it was done. On Fri, Jun 14, 2013 at 6:45 PM, Tom Van Baak t...@leapsecond.com wrote: Since the topic of WWVB came up again, here's another idea. A number of people still want to use (hp, or Tracor, or) Spectracom WWVB receivers as frequency standards or to maintain NIST traceability. As has been discussed on the list, these receivers no longer work now that the enhanced WWVB format is in effect 24/7. Paul Swed's Costas loop project is a nice hardware solution. I'm wondering if anyone wants to help on a mostly software solution. Here's the idea -- if you already know the time of day to a few milliseconds (from NTP, GPS, etc.) it should be simple to generate the live 1 baud data of the new PM code. The only hardware you need is an analog inverter/switch which then applies either a 0 or 180 degree shift to the antenna signal, based on the predicted state of the PM code for that second. In this case, every second, your local phase shifting neatly cancels the Ft Collins phase shifting. The PM bit prediction and edge timing don't have to be perfect, just close enough that the 60 kHz PLL stays happily locked. The advantage of this approach is that the existing WWVB phase tracking receiver can remain completely unmodified. You would simply insert the programmable inverter inline between the antenna and the receiver. For testing even a DPDT reed relay might do the job. It would be a good project for a RPi (running an NTP client) or an Arduino (using a cheap GPS NMEA+1PPS receiver). If you can spot holes in the design let me know. It seems too simple to be true. /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. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing 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] HP and other equipment failure...
My HP-3336A was purchased from an auction (not eBay) and came out of a Southern California lab that was shutting down. The small heat sink ran awfully hot. I added a larger heat sink and it eventually became pretty hot also. What I discovered was the line voltage was set to 100 volts, not 120 volts. I know for sure that this instrument was used in the US. Changing it to 110-120 resolved the problem and it now runs cool. I should've checked the line voltage setting when it arrived, but I just assumed... Burt, K6OQK Subject: Re: [time-nuts] HP and other equipment failure Talking of Cooling HP 5370's, I have a 12V fan Gorilla taped to mine fed from a wallwart. Not elegant, but it has reduced the heat sink temperature dramatically. Is anyone else concerned about the heat sink temperature on the 5370? Has anyone done a fan modification they would care to share? Also, my 8566A RF section pass transistor heat sink gets awfully warm too, does anyone have a sensible solution? -marki Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing 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] Have 10 MHz need 19.2 MHz
List, My reply to Javier Herrerojherr...@hvsistemas.es P Double the 10 MHz to 20 MHz. P With another circuit of 74HC390’s divide 10 MHz to 200 KHz. Then double it twice to 800 KHz with LM 1496 DBM’s. Apply the two frequencies to a LM 1496 DBM and use a LPF to get the 19.2 MHz. P Hardware complicated? A bit. J Only a bit? Only the filter to reject the products that you will have spread in all places, spaced 200 kHz, P I’m not so sure of that at all. The DBM doubler has a difference frequency of zero. And I don’t understand where did you get 200 KHz spaces? J and mainly to remove the 20.8 MHz spurious that you will have as a result of the last mixing, makes this approach difficult. P You are correct that the sum frequency is 20.8 MHz. However the difference frequency being 19.2 MHz makes a 1.6 MHz difference which will allow one to use a simple parallel L-C circuit to get the frequency of choice rather simply. A parallel resonance filter (ignoring stray capacitance for the moment) using a .1uH inductor and a 687pF capacitor resonates at 19.20175 MHz. J I would favour a PLL, and since for the application, short-term stability seems irrelevant, even using a conventional VCO and not a crystal would be enough. A 74HC4046 can reach 19.2 MHz, and you only need a couple of dividers to get a 200 kHz reference to feed it. P That may be another way to do it. I didn’t say my way was thee only way. I said it might be a way. And until one built my circuit idea criticizing that it won’t work well is hypothetical and somewhat arrogant. Building it is the real proof. Never forget about the duck-billed platypus, the animal that couldn’t be, according to *scientific laws*. P According to the data sheets I have for a 74HC4046 to use it at 19.2 MHz you have to be brand specific. Some are only rated to 14 MHz P I thought that the 10 MHz source was a rubidium. That may have been incorrect. If the short term stability is irrelevant as you have stated then other possibilities are also feasible. P But if one uses a 74HC4046 with a VCO (which would be fine with me) one still has to get two matching frequencies. J I figured out the 200 KHz division. P How would you get 200 KHz from the 19.2 MHz for the PLL and where does this come from and how does it fit into your circuit. P Can you use matching harmonics in a PLL? I don’t know. I’m a hobbyist and have to go with what I know or can get from others. J However one doesn’t have to search for a microprocessor that you program and may not be available in a couple of years. The IC’s are cheap and have been and will be around forever. J The LM1496 was discontinued long ago it was a second source of the MC1496 (that is in production). P OK. But a rose is still a rose. Mouser currently has stock of over 4,000 MC1496 for immediate delivery. They are interchangeable. So what is your point? The specified type of DBM is currently available. Sir, methinks, respectfully, that thy are quibbling over nothing, J But never think it will be around forever (yes, as a hobbyist, surely you can find a single piece forever, more if price does not matter too much). P Well some parts whose use is so pervasive, for example, the 2N3904 and 2N3906 transistor, they will be around *forever* and reasonably priced. I believe the MC or LM 1496 falls in this category. Everyone had and still uses them. Although there are a few other IC DBM’s they really are insignificant and very hard to find. J Also, I'm not a bit fan of PICs, quite the contrary, but for example the PIC16F84 has been available from more that 16yr and it is in production... so following your LM1496 criteria, will be available forever :) P OK, but you still have to be able to program any PIC one chooses. Most prevalent posters to the list are programmers or have been trained in programming or like it enough to learn it and do it. Fine. Go for it. Their skill is indispensible in this world. Now comes the BUT part. IMNSHO, I believe that their (programmers) judgment is quite slanted to using microprocessors as a solution to all electrical problems. This leads to over-complicated solutions to many problems. This is actually poor engineering practice. Good engineering is finding the least expensive, reliable, simplest and reproducible method to solve a given problem. Many of us have no skill to use microprocessors. So we find a work-a-round. Microprocessors are fine. Microprocessor use gives us a great quality of life. Modern life as developed nations have would not exist without them. We couldn’t be spied upon without them! P IMHO sometimes an older *brute force* circuit proves that more can be less in implementing what you desire to accomplish. J Brute force is usually brute :) P Perhaps. But if a circuit works reliably, fulfills its objective, and is easily reproduced by others that can easily outweigh
Re: [time-nuts] Beaglebone NTP server
Can you explain what is different in this approach versus the traditional gps/pps without needing a custom clocksource? On Fri, Jun 14, 2013 at 8:13 PM, Gabs Ricalde gsrica...@gmail.com wrote: As an alternative to the Net4501, the AM335x in the Beaglebone has timers that accept an external clock up to 25 MHz (TCLKIN) and can timestamp events on an input pin (TIMER4-TIMER7). Both sets of pins are available on the headers after an appropriate pinmux configuration. I'm finishing the clocksource driver for Linux, I'm testing it using the 10 MHz and PPS outputs of a LEA-6T. ntpd loopstats show +/- 0.1 us offsets, frequency is a flat 0.000 PPM as expected. ___ time-nuts mailing 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.
