Re: [time-nuts] Leap second smear at Google
I don't know how elegant this solution from Google is Christopher, It's a clever, internal solution to the difficult problem leap seconds create in any large automated system. That blog entry is 2 years old. The issue has been discussed at length on the leap second mailing list; you can read the archives, if you have the time. /tvb www.leapsecond.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] Space mission comes to an end because of a computer time tagging problem
David, The satellite has probably got a Rb as its clock (hopefully more than one). All I can imagine is that there has been a major clock failure of some sort, and everything is in free run and unable to sync up with ground. Thoughts? Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David J Taylor Sent: 20 September 2013 17:51 To: Time-nuts mailing list Subject: [time-nuts] Space mission comes to an end becuase of a computer time tagging problem NASA's Deep Space Comet Hunter Mission Comes to an end The news release includes this paragraph: After losing contact with the spacecraft last month, mission controllers spent several weeks trying to uplink commands to reactivate its onboard systems. Although the exact cause of the loss is not known, analysis has uncovered a potential problem with computer time tagging that could have led to loss of control for Deep Impact's orientation. That would then affect the positioning of its radio antennas, making communication difficult, as well as its solar arrays, which would in turn prevent the spacecraft from getting power and allow cold temperatures to ruin onboard equipment, essentially freezing its battery and propulsion systems. Knowing the membership of this group, does anyone have more insight into what the computer time tagging problem might be? Thanks, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing 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] Space mission comes to an end because of a computer time tagging problem
If I was to make an educated guess about this one I'd say that it is more likely to be an overflow problem. The spacecraft was operating for significantly longer than it's builders or programmers ever considered likely. -Geoff. On Sat, 21 Sep 2013 07:30:54 pm Rob Kimberley wrote: David, The satellite has probably got a Rb as its clock (hopefully more than one). All I can imagine is that there has been a major clock failure of some sort, and everything is in free run and unable to sync up with ground. Thoughts? Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David J Taylor Sent: 20 September 2013 17:51 To: Time-nuts mailing list Subject: [time-nuts] Space mission comes to an end becuase of a computer time tagging problem NASA's Deep Space Comet Hunter Mission Comes to an end snipped ___ time-nuts mailing 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] Low Phase Noise Ref?
Tom, On 09/20/2013 06:37 PM, Tom Knox wrote: We all have our idea of what a low or Ultra Low phase noise oscillator is. For 5 and 10MHz references I usually look first at 1Hz offset then the noise floor. At 5MHz I consider 125dB @ 1Hz state of the art. But now with work by Archita Hati and colleges at NIST I guess I will need to rethink that. All I want to know is when will it be available as a single chip. And how long before Magnus, TVB, and other Senior Time-Nut have a workable prototype in their labs? Enjoy Thomas Knox Ascent Concepts and Technology 4475 Whitney Place Boulder Colorado 80305 1-303-554-0307 As time-nuts, we want multiple units in our labs. :) That's why I keep a hoard of BVAs for instance. Keeping pace with Archita is a challenge for sure. I'm lagging behind in many aspects. Darn. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Space mission comes to an end because of a computer time tagging problem
On 9/21/13 2:30 AM, Rob Kimberley wrote: David, The satellite has probably got a Rb as its clock (hopefully more than one). Very, very few deep space probes carry a Rb ( I can't think of any off hand). Regular old quartz, usually some sort of tcxo. If they are doing radio science, then it might carry a USO, which is essentially a high quality OCXO. There's relatively little on a spacecraft that needs precision timing. What typically happens is that the telemetry coming down includes the current time from whatever clock is on board. The spacecraft time tag will be referenced to a particular bit in the telemetry frame. In the at the tone the time is model, the tone is a particular bit. Then on the ground, we time tag (with an atomic clock) when the telemetry frame is received. (giving you Earth Received Time or ERT) Someone on the ground does a process of time correlation figuring out what spacecraft time corresponds to what TAI time, allowing for the various factors like the light time from spacecraft to the earth station. When sequences (lists of commands and what time they are to be executed) are built, they're in spacecraft time. So the folks on the ground take the current best estimate of the transformation between earth time and spacecraft time and calculate it accordingly. Since spacecraft operations are fairly slow paced, the accuracy needed is on the order of seconds. Even for fairly critical things like trajectory correction maneuvers, I think they've got a fair amount of slop in the system (tens of seconds?) for when the burn has to occur (the thrust is small and they run for a long time). This is partly why autonomous entry, descent and landing (EDL) for something like Curiosity is so impressive and useful. They spend a lot of time just before EDL carefully correlating the time tags and the measurements using doppler and range to get the state vector refined as well as possible, line everything up with the internal inertial measurement unit, give it the best starting point they can. Then they send their last best estimates and the process starts. All I can imagine is that there has been a major clock failure of some sort, and everything is in free run and unable to sync up with ground. Not likely. Nothing in the comm process requires time sync. The radio on the spacecraft is always on, listening for a signal. it is at a fixed frequency (determined by the TCXO inside the radio). The ground station transmits and the frequency is swept slowly across a range where the spacecraft is likely to be listening. Usually, we have been keeping track of what the best lock frequency is vs temperature, and with a temperature estimate, and the Doppler estimate, the range to sweep isn't all that big. As the signal sweeps across the receiver's bandwidth, the oscillator in the receiver locks to the uplink signal (and follows it). It's a fairly straightforward PLL, with a 2nd or 3rd order loop filter. The loop bandwidth depends on the received signal strength but is in the 10 Hz range. The radio's transmitter is driven by the same oscillator (the VCTCXO) as in the receiver's carrier tracking loop PLL. So the transmitted signal frequency and phase has a fixed relationship with the received frequency and phase. This is called the turnaround ratio and is 880/749 for Deep Space X band. By comparing the phase of the uplink signal at DSN and the downlink signal received, we can measure the range and Doppler very precisely. (for instance, we know the range to Cassini within a few cm, even though it's at Saturn some billion km away) What does happen over the life of the mission is that the rest frequency of the VCXO in the radio gradually shifts (radiation, aging, etc.) and it's possible that it shifts so far that either we can't find it (unlikely, because what you'd do is start sweeping a wider range), that something in the carrier tracking loop has drifted that it can't acquire and track the uplink carrier (the tuning voltage can't change far enough or fast enough), or something like that. Or the frequency has gotten out of the sweet spot. At some point, the gain falls off a bit, and if you're operating on the low gain antenna, even if you turn the power to 11 at DSN, there's just not enough SNR to get the carrier to lock. These things are operating at the ragged edge of performance. When we test them, we're using received signal powers in the -160 to -150 dBm (threshold testing). With a noise figure of a few dB and a loop (detection) bandwidth of 10 Hz, that's where the noise floor is. There's a few dB of variation in the threshold Prec as a function of receive frequency (hence the term best lock frequency) We typically monitor the loop sress on the receiver (essentially like watching the EFC voltage on a GPSDO) and if the locked tuning voltage starts getting close to the rail, people start to worry.
Re: [time-nuts] Space mission comes to an end becuase of a computer time tagging problem
On 9/20/13 5:12 PM, Bob Camp wrote: Hi Low bid wrist watch used as time base? - I'd bet there is some form of master time tick in their RTOS that keeps everything pumping. Loose the time tick (or the time tick count) and it all goes away… yes and no. Most spacecraft have a default strategy if everything got reset, so they don't need to know what time it is. They go into safe hold mode. There's several steps in the strategy. If you have attitude knowledge, you'll sun/earth point the high gain antenna and wait to hear from the ground. If you don't have attitude knowledge, you shift to the low gain omni antenna, and wait to hear from the ground. DSN cranks up the Tx power, and they transmit at a very low rate (10 bits/sec) to try and get a command in through the LGA. If you've totally lost attitude control, and you're slowly rotating, you still might not get a command it, because there's no such thing as a truly omni antenna pattern: it has lumps and bumps and nulls. However, unless there's no attitude control authority (e.g. if you have wheels and they've failed, or you've run out of propellant), you don't need to know the time to be able to stabilize the spacecraft in one attitude. And once you're stabilized, you can get that command in. So there's some other more complex problem. As the onboard computers accumulate radiation induced faults, there's a lot of software patching that goes on to map around the faulty sections. They may have done one to may patches. I don't think that is the case with DI. Radiation causes upsets, but they're usually a transient thing, and rewriting the memory fixes it. Most of the time it's using EDAC on the memory, and scrubbing. One can send commands from the ground that will kill it accidentally. Spacecraft have typically very simple command structures. A lot of commands are basically poke this value at this address and with knowledge on the ground of which control paramters are stored at which addresses, you can build your commands. However, if you poke the wrong address, or send the wrong value, you can command the spacecraft to do something that is irrecoverable. One of the Mars spacecraft was lost because of this. People often ask why doesn't it have range checking and validation on the parameters. Well.. that would take more code, and memory is a limited resource. And, it's not like there's a command parser in the sense of a shell that interprets and validates commands. The spacecraft checks the checksum on the received message, and does it. This comes from a long history where spacecraft had very simple control systems (no computer). You'd have a bunch of relays and the message that comes up has a bit for each relay or control line. The command detector unit sees the frame sync bit sequence and then just loads the bits into a big register, and when the checksum is ok, it latches them all in. It's much like how 1553 works. You assign each word or bit to some actuator or sensor, and it's more like remote memory access than actual commanding. The whole process works the same on downlink. In fact, even though we now use computers, it's still called decommutation Bob ___ time-nuts mailing 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] Space mission comes to an end becuase of a computer time tagging problem
from JPL http://www.jpl.nasa.gov/news/news.php?release=2013-275 Mission controllers postulate that there was an anomaly generated by the spacecraft's software which left the vehicle's computers in a condition where they are continuously rebooting themselves. If this is the case, the computers would not continue to command the vehicle's thrusters to fire and hold attitude. Lack of attitude hold makes attempts to reestablish communications more difficult because the orientation of the spacecraft's antennas is unknown. It also brings into question the vehicle's electrical power status, as the spacecraft derives its power from a solar array that is fixed, with its cells pointing in one direction. If it gets cold enough (without power from solar cells, it won't generate enough internal heat to keep warm), it will die. That's probably what happened to Spirit on Mars. It got cold enough during the Martian winter, and with not enough solar power, enough things drifted cold enough that we couldn't get commands in. BTW, DI uses star trackers for attitude knowledge, so it has the potential to point very precisely. If anyone is interested in the gory details of how the telecom system works http://descanso.jpl.nasa.gov/DPSummary/di_article_cmp20050922.pdf Page 20 shows the variation in AuxOsc frequency of the SDST radio vs temperature. That shape will look pretty familiar to list members. ___ time-nuts mailing 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] Space mission comes to an end because of a computer time tagging problem
Hi I'd be a bit surprised if they were running anything as power hungry as an Rb all the time when a quartz based device would be smaller / lower power / lower volume. Of course they may have had mission requirements that drive them to a hydrogen maser ... Bob On Sep 21, 2013, at 5:30 AM, Rob Kimberley robkimber...@btinternet.com wrote: David, The satellite has probably got a Rb as its clock (hopefully more than one). All I can imagine is that there has been a major clock failure of some sort, and everything is in free run and unable to sync up with ground. Thoughts? Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David J Taylor Sent: 20 September 2013 17:51 To: Time-nuts mailing list Subject: [time-nuts] Space mission comes to an end becuase of a computer time tagging problem NASA's Deep Space Comet Hunter Mission Comes to an end The news release includes this paragraph: After losing contact with the spacecraft last month, mission controllers spent several weeks trying to uplink commands to reactivate its onboard systems. Although the exact cause of the loss is not known, analysis has uncovered a potential problem with computer time tagging that could have led to loss of control for Deep Impact's orientation. That would then affect the positioning of its radio antennas, making communication difficult, as well as its solar arrays, which would in turn prevent the spacecraft from getting power and allow cold temperatures to ruin onboard equipment, essentially freezing its battery and propulsion systems. Knowing the membership of this group, does anyone have more insight into what the computer time tagging problem might be? Thanks, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing 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] Space mission comes to an end becuase of a computer time tagging problem
Hi So it's a pretty good AT cut crystal without any compensation of heating. Not quite a cheap wrist watch, but not a BVA in a dewar flask either. Bob On Sep 21, 2013, at 8:11 AM, Jim Lux jim...@earthlink.net wrote: from JPL http://www.jpl.nasa.gov/news/news.php?release=2013-275 Mission controllers postulate that there was an anomaly generated by the spacecraft's software which left the vehicle's computers in a condition where they are continuously rebooting themselves. If this is the case, the computers would not continue to command the vehicle's thrusters to fire and hold attitude. Lack of attitude hold makes attempts to reestablish communications more difficult because the orientation of the spacecraft's antennas is unknown. It also brings into question the vehicle's electrical power status, as the spacecraft derives its power from a solar array that is fixed, with its cells pointing in one direction. If it gets cold enough (without power from solar cells, it won't generate enough internal heat to keep warm), it will die. That's probably what happened to Spirit on Mars. It got cold enough during the Martian winter, and with not enough solar power, enough things drifted cold enough that we couldn't get commands in. BTW, DI uses star trackers for attitude knowledge, so it has the potential to point very precisely. If anyone is interested in the gory details of how the telecom system works http://descanso.jpl.nasa.gov/DPSummary/di_article_cmp20050922.pdf Page 20 shows the variation in AuxOsc frequency of the SDST radio vs temperature. That shape will look pretty familiar to list members. ___ time-nuts mailing 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] Space mission comes to an end because of a computer time tagging problem
Jim, On 09/21/2013 01:32 PM, Jim Lux wrote: On 9/21/13 2:30 AM, Rob Kimberley wrote: David, The satellite has probably got a Rb as its clock (hopefully more than one). Very, very few deep space probes carry a Rb ( I can't think of any off hand). Regular old quartz, usually some sort of tcxo. If they are doing radio science, then it might carry a USO, which is essentially a high quality OCXO. lots of nice description here We typically monitor the loop sress on the receiver (essentially like watching the EFC voltage on a GPSDO) and if the locked tuning voltage starts getting close to the rail, people start to worry. All this is really, keep the bird simple as simple can be and keep the complexity at ground where we can fix it. Upgrading firmware is sensitive, you just don't want to brick it. Thanks for sharing. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP 5061A Problem
I got a 5061A with high performance tube that I'm trying to get running. The Cs oven works and the -3500 and -2500V are there. The beam current has its maximum at the correct frequency. 90MHz from the multiplier are there and they are phase modulated with 137Hz at about 0.01 rad. Measured on a spectrum analyzer, the 137Hz sidebands are some -47dBc. I'm not sure if that low modulaion index is correct though. Also, the harmonic generator alignment worked as described in the manual. Measured with the EM output into a 10M input DMM, the floor was around -60mV, finally set to some -90mV after alignment. The low frequency test worked as well and delivered a maximum at some 41.6kHz. An unusual observation is that the meter indicates beam current immediately after switching the CBT on. Nevertheless, it could be tuned to the correct maximum after warming up. However, there is still no 2nd harmonic and it doesn't lock. Measured with a scope directly at the EM output, there is mainly noise with just a faint signal when maxed with the A3 mod level potentiometer. Unfortunately, I couldn't find reference data in the manual, neither for the beam current nor the multiplier modulation index. So far, everything seems to work properly except for the missing 2nd harmonic and the unusual beam curren behavior. Any help would be much appreciated. Adrian ___ time-nuts mailing 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] Space mission comes to an end becuase of a computer time tagging problem
On 09/21/2013 02:52 PM, Bob Camp wrote: Hi So it's a pretty good AT cut crystal without any compensation of heating. Not quite a cheap wrist watch, but not a BVA in a dewar flask either. The environmental perturbations should go quite slow most of the time, as it glides in the void slowly away and often have a fairly stable direction with regards to the sun. If they have spin-rotation it complicates things a bit. Decent dewar-flask with better background radiation and one major heat source that you track for the solar panels. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Space mission comes to an end because of a computer time tagging problem
On 9/21/13 5:41 AM, Bob Camp wrote: Hi I'd be a bit surprised if they were running anything as power hungry as an Rb all the time when a quartz based device would be smaller / lower power / lower volume. Of course they may have had mission requirements that drive them to a hydrogen maser ... Quartz is king.. either a TCXO or maybe an OCXO or USO But this is why the Deep Space Atomic Clock (a trapped Hg+ ion clock) is so interesting. It has the potential of beating the USO in performance, size, mass, and delivery lead time. A USO takes a long time to build. You need to get a bunch of crystals and oscillators and run them to see what the aging characteristics are, etc. An atomic standard doesn't have the carefully selected crystal issue. ___ time-nuts mailing 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] Space mission comes to an end becuase of a computer time tagging problem
On 9/21/13 5:52 AM, Bob Camp wrote: Hi So it's a pretty good AT cut crystal without any compensation of heating. Not quite a cheap wrist watch, but not a BVA in a dewar flask either. Yep. The AuxOsc is what is used if you don't want to have the downlink locked to the uplink. ___ time-nuts mailing 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] Space mission comes to an end becuase of a computer time tagging problem
On 9/21/13 6:03 AM, Magnus Danielson wrote: On 09/21/2013 02:52 PM, Bob Camp wrote: Hi So it's a pretty good AT cut crystal without any compensation of heating. Not quite a cheap wrist watch, but not a BVA in a dewar flask either. The environmental perturbations should go quite slow most of the time, as it glides in the void slowly away and often have a fairly stable direction with regards to the sun. If they have spin-rotation it complicates things a bit. Decent dewar-flask with better background radiation and one major heat source that you track for the solar panels. Yeah, there's jokes about why are they obsessing about hermetic seals on components when we're going to be operating in a harder vacuum than you can easily achieve on earth. The outside of the package probably has a lower pressure than inside the package. ___ time-nuts mailing 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] Space mission comes to an end becuase of a computer time tagging problem
On 09/21/2013 03:26 PM, Jim Lux wrote: On 9/21/13 6:03 AM, Magnus Danielson wrote: On 09/21/2013 02:52 PM, Bob Camp wrote: Hi So it's a pretty good AT cut crystal without any compensation of heating. Not quite a cheap wrist watch, but not a BVA in a dewar flask either. The environmental perturbations should go quite slow most of the time, as it glides in the void slowly away and often have a fairly stable direction with regards to the sun. If they have spin-rotation it complicates things a bit. Decent dewar-flask with better background radiation and one major heat source that you track for the solar panels. Yeah, there's jokes about why are they obsessing about hermetic seals on components when we're going to be operating in a harder vacuum than you can easily achieve on earth. The outside of the package probably has a lower pressure than inside the package. True. The trouble is really what happens prior to reaching that hard vacuum. You could do a in space pumping by having the thing pressurized and then heat up a lead-plug until it melts and the pressure shoots out the blob, gas and eventually the innards decays into hard vacuum. If you do that early in the mission, the handling the shift is relatively easy as C/N ratios is favorable. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 5061A Problem
Adrian It looks like you are gathering a lot of good detail. I have a couple of thoughts. But will say there are many on this list that are far far more knowledgeable then me. My experience was in building a hp 5060/61 combo. A mixed marriage that worked. That said. You don't mention the current reading. I understand thats really relative but would be curious. So possibilities. The photo multiplier in the tube is actually a tube. They can go noisey with age. That would be the masking effect that would prevent 2nd harmonic. To much current may be an additional issue. Lastly the frontend transistors of the photo mult preamp may be going bad. Just some thoughts. Regards Paul. WB8TSL On Sat, Sep 21, 2013 at 8:27 AM, Adrian rfn...@arcor.de wrote: I got a 5061A with high performance tube that I'm trying to get running. The Cs oven works and the -3500 and -2500V are there. The beam current has its maximum at the correct frequency. 90MHz from the multiplier are there and they are phase modulated with 137Hz at about 0.01 rad. Measured on a spectrum analyzer, the 137Hz sidebands are some -47dBc. I'm not sure if that low modulaion index is correct though. Also, the harmonic generator alignment worked as described in the manual. Measured with the EM output into a 10M input DMM, the floor was around -60mV, finally set to some -90mV after alignment. The low frequency test worked as well and delivered a maximum at some 41.6kHz. An unusual observation is that the meter indicates beam current immediately after switching the CBT on. Nevertheless, it could be tuned to the correct maximum after warming up. However, there is still no 2nd harmonic and it doesn't lock. Measured with a scope directly at the EM output, there is mainly noise with just a faint signal when maxed with the A3 mod level potentiometer. Unfortunately, I couldn't find reference data in the manual, neither for the beam current nor the multiplier modulation index. So far, everything seems to work properly except for the missing 2nd harmonic and the unusual beam curren behavior. Any help would be much appreciated. Adrian __**_ 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.
[time-nuts] FE-5680A Loop Lock Indicator
The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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 5061A Problem
Adrian, Most used High stability tubes are DOA but you might get lucky! You say the low frequency test worked. What was the amplitude of the peak in nanoamps and was the peak well above the noise or baseline level? Once you were on the peak did you adjust the 41.6Khz amplitude to max the signal? Once on the peak you can adjust the mass spec pot on the top of A11 to peak it. If the peak was 8na and above noise then the tube appears to be working. Anything below 4 or 5 na the tube is depleted, might be useable but STS will be terrible. If the peak is 8na then reconfigure for normal operation, in open loop mode. Turn the mod on and connect a scope to A8 J1 to observe the phase detector output. Adjust the fine and or coarse oscillator adjustments back and forth across 5Mhz. If you can see any output as you sweep through then set the osc. frequency to peak the signal. Then adjust the A3 mod and the A4 (top pot) to peak the signal. A7 gain will adjust the amplitude. Adj the osc freq. to null the signal (puts you on frequency) and see if you have any 2nd harmonic now. If so go ahead and see if it will lock. Good Luck! Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Doppler and FMT
On 09/20/2013 04:34 AM, quartz55 wrote: But when working with clocks (time, frequency, stability measurements) this assumption often not true and it's helpful to think of averaging more as a disease than a cure. /tvb I can understand that. 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. Rather, averaging is a good tool when applied right. In the field of time and frequency, it can be tricker to apply it right, as it does not always do what you expect it to do. When we collect our stability measures for instance, we average only after we have done pre-processing tailored to handling the obscure noises we have that would otherwise make our averaging blow-up in our faces. So, like any tool, it needs to be applied with proper knowledge. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680A Loop Lock Indicator
Are you applying +5V to pin as well? See: http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:fe5680a_faq Within 5 minutes after powering up (apply +15V on DB9 pin 1 and +5V on pin 4) the unit should indicate lock (pin 3 voltage drops low). John WA4WDL -- From: Bob Stewart b...@evoria.net Sent: Saturday, September 21, 2013 10:55 AM To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] FE-5680A Loop Lock Indicator The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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] FE-5680A Loop Lock Indicator
Hi John, Thanks for the response. I don't think my unit is the same as that one. The instructions I got did not mention any +5V. Also, this is not a 10MHz unit, it is only a timing unit. The internal frequency is 8.38860798/9 (last digit jitter) MHz. Bob From: jmfranke jmfra...@cox.net To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 10:45 AM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Are you applying +5V to pin as well? See: http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:fe5680a_faq Within 5 minutes after powering up (apply +15V on DB9 pin 1 and +5V on pin 4) the unit should indicate lock (pin 3 voltage drops low). John WA4WDL -- From: Bob Stewart b...@evoria.net Sent: Saturday, September 21, 2013 10:55 AM To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] FE-5680A Loop Lock Indicator The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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] Space mission comes to an end becuase of a computer time tagging problem
from JPL http://www.jpl.nasa.gov/news/news.php?release=2013-275 Mission controllers postulate that there was an anomaly generated by the spacecraft's software which left the vehicle's computers in a condition where they are continuously rebooting themselves. If this is the case, the computers would not continue to command the vehicle's thrusters to fire and hold attitude. Lack of attitude hold makes attempts to reestablish communications more difficult because the orientation of the spacecraft's antennas is unknown. It also brings into question the vehicle's electrical power status, as the spacecraft derives its power from a solar array that is fixed, with its cells pointing in one direction. If it gets cold enough (without power from solar cells, it won't generate enough internal heat to keep warm), it will die. That's probably what happened to Spirit on Mars. It got cold enough during the Martian winter, and with not enough solar power, enough things drifted cold enough that we couldn't get commands in. BTW, DI uses star trackers for attitude knowledge, so it has the potential to point very precisely. If anyone is interested in the gory details of how the telecom system works http://descanso.jpl.nasa.gov/DPSummary/di_article_cmp20050922.pdf Page 20 shows the variation in AuxOsc frequency of the SDST radio vs temperature. That shape will look pretty familiar to list members. ___ Thanks, Jim, for the press release details, and the article pointer. Still doesn't say what the anomaly was, but I guess we will never know. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing 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] FE-5680A Loop Lock Indicator
If the lock output comes from the micro or a logic port with a maximum output of 3.3 or 5V, a LED connected to it from +15 will be always ON. On Sat, Sep 21, 2013 at 4:55 PM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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] FE-5680A Loop Lock Indicator
There is a problem introduced if you sink too much current off the lock pin. An LED draws enough current to cause the issue, I think to do with not going into lock or PPS output. If I could just remember what the issue is... Anyway, this guy has it nailed: http://www.ka7oei.com/10_MHz_Rubidium_FE-5680A.html Except, the ones that I have that need a +5V supply are programmable. Go figure.. --marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Sunday, 22 September 2013 1:25 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator If the lock output comes from the micro or a logic port with a maximum output of 3.3 or 5V, a LED connected to it from +15 will be always ON. On Sat, Sep 21, 2013 at 4:55 PM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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] New NTBW50AA
R is to read files. I tried all 3 reset (!) commands, warm, cold and hard. (and said 'OH no what have I done) Warm locked in about 3 minutes and cleared the holdover, cold locked in 10 minutes, hard locked in 10 minutes but cleared the lat lon, reset the EL to 10, AMU to 4. I put the lat lon and alt back in and after the almanac came back up in about 16 minutes, everything else remained the same. Seem to have to force LH to stop and re-start each time. I'm looking at the signal strength vs. az/el and I'll let it run for a while. I still hardly ever see much above 43-45 dBc. I have new cable coming, so maybe that will help but I doubt it. I may try the K7KKQ antenna and an amp from mouser. Dave - Original Message - From: James Tucker To: Discussion of precise time and frequency measurement Sent: Friday, September 20, 2013 10:38 PM Subject: Re: [time-nuts] New NTBW50AA LH has provisions for various reset levels; I don't know if they apply to the Nortel. Try 'r', and see where that leads. JimT ___ time-nuts mailing 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] Reflections and Low Phase Noise
If this at first appears to be off topic read on. Having this year survived fire evacuations and most recently what has been called anything from a five to 1000 year flood here in Boulder, I have has a little time to reflect on just how lucky I was. Over the last few years I have made a few upgrades to harden my home against natural disasters. Adding sprinklers to the roof and a industrial sump pump in my basement. To say the least it paid off in a big way last week, since if my basement had flooded I would have lost my lab that I have spent several decades building. It has motivated me to finish upgrading my grounding and lightning protection with a new eye to detail. I write this post to encourage others to do the same by spending a few minutes to look for any vulnerabilities and spend a few days addressing them. Or at least upgrading insurance. For many here in Boulder lately there is nothing they could have done, but for amny other a few minutes could have saved them months of work. If I can help just one Time-Nut save his lab it is worth it. Now for the good stuff, We all have our idea of what a low or Ultra Low phase noise oscillator is. For 5 and 10MHz references I usually look first at 1Hz offset then the noise floor. At 5MHz I consider 125dB @ 1Hz state of the art. But now Arcihita Hati and colleges at NIST has designed a State-of-the-Art RF Signal Generation From Optical Frequency Division that sets a new standard for low phase noise with nearly -155dB @ 1Hz for a 5MHz reference. All I want to know is when will it be available as a single chip. And how long before Magnus, TVB, and other Senior Time-Nut have a workable prototype in their labs? The NIST link is not yet active, but if you would like a copy of the paper now email me off list I will send you the paper as an attachment. I think it may also be posted on IEEE's pay to play site. Thomas Knox ___ time-nuts mailing 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 5061A Problem
If you have another reference like a GPS or Rubidium it makes set up much easier since you simply tune to 5MHz and then adjust current. The High Perf Tubes often needed to be degaussed, I have the 10638A but no cable if that is any help contact me off list. Also placing an external power supply on the ion pump is often needed if the clock has been stored for a long period. In the past I could talk you through set up on the phone but now I would need it in front of me, sorry. Thomas Knox Date: Sat, 21 Sep 2013 14:27:38 +0200 From: rfn...@arcor.de To: time-nuts@febo.com Subject: [time-nuts] HP 5061A Problem I got a 5061A with high performance tube that I'm trying to get running. The Cs oven works and the -3500 and -2500V are there. The beam current has its maximum at the correct frequency. 90MHz from the multiplier are there and they are phase modulated with 137Hz at about 0.01 rad. Measured on a spectrum analyzer, the 137Hz sidebands are some -47dBc. I'm not sure if that low modulaion index is correct though. Also, the harmonic generator alignment worked as described in the manual. Measured with the EM output into a 10M input DMM, the floor was around -60mV, finally set to some -90mV after alignment. The low frequency test worked as well and delivered a maximum at some 41.6kHz. An unusual observation is that the meter indicates beam current immediately after switching the CBT on. Nevertheless, it could be tuned to the correct maximum after warming up. However, there is still no 2nd harmonic and it doesn't lock. Measured with a scope directly at the EM output, there is mainly noise with just a faint signal when maxed with the A3 mod level potentiometer. Unfortunately, I couldn't find reference data in the manual, neither for the beam current nor the multiplier modulation index. So far, everything seems to work properly except for the missing 2nd harmonic and the unusual beam curren behavior. Any help would be much appreciated. Adrian ___ time-nuts mailing 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] Reflections and Low Phase Noise
Tom: I would like to see that paper. Thanks, jim wb4...@amsat.org On 9/21/2013 1:50 PM, Tom Knox wrote: If this at first appears to be off topic read on. Having this year survived fire evacuations and most recently what has been called anything from a five to 1000 year flood here in Boulder, I have has a little time to reflect on just how lucky I was. Over the last few years I have made a few upgrades to harden my home against natural disasters. Adding sprinklers to the roof and a industrial sump pump in my basement. To say the least it paid off in a big way last week, since if my basement had flooded I would have lost my lab that I have spent several decades building. It has motivated me to finish upgrading my grounding and lightning protection with a new eye to detail. I write this post to encourage others to do the same by spending a few minutes to look for any vulnerabilities and spend a few days addressing them. Or at least upgrading insurance. For many here in Boulder lately there is nothing they could have done, but for amny other a few minutes could have saved them months of work. If I can help just one Time-Nut save! his lab it is worth it. Now for the good stuff, We all have our idea of what a low or Ultra Low phase noise oscillator is. For 5 and 10MHz references I usually look first at 1Hz offset then the noise floor. At 5MHz I consider 125dB @ 1Hz state of the art. But now Arcihita Hati and colleges at NIST has designed a State-of-the-Art RF Signal Generation From Optical Frequency Division that sets a new standard for low phase noise with nearly -155dB @ 1Hz for a 5MHz reference. All I want to know is when will it be available as a single chip. And how long before Magnus, TVB, and other Senior Time-Nut have a workable prototype in their labs? The NIST link is not yet active, but if you would like a copy of the paper now email me off list I will send you the paper as an attachment. I think it may also be posted on IEEE's pay to play site. Thomas Knox ___ time-nuts mailing 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 5061A Problem
Corby, many thanks for the comprehensive instructions. After the harmonic generator alignment I measured 90mV into the 10Meg DMM input, so the beam current should be 9nA. The floor with the harmonic generator pot fully ccw was 6nA. I didn't change the generator output during the LF test. To get to the maximum, I just had to increase the frequency up to about twice the initial value of some 21kHz. The peak was a lot above the noise. But, now I'm suspecting that the CBT has probably been exchanged by the previous owner and not been set up correctly. Either he decided to dispose a dead CBT or he gave up half way... I hope the latter. On the CBT label it says EM voltage -1615V. The applied voltage is actually -2500V. I see in an old post you mentioned that the higher voltage should be ok for now. Well, and something with the Zeeman frequency appears to be wrong, too. The measured (some) 41,6kHz from the LF test don't match the 53.53kHz sticker on the door. So I'm wondering what else needs to be checked. The synthesizer output is 12.631,771,6MHz as indicated in the manual. Btw. this 5061A has Opt. H96 which seems to indicate the added alarm and continuous operation outputs on the rear, and a A5 time delay divider. There is no clock. Thanks, Adrian cdel...@juno.com schrieb: Adrian, Most used High stability tubes are DOA but you might get lucky! You say the low frequency test worked. What was the amplitude of the peak in nanoamps and was the peak well above the noise or baseline level? Once you were on the peak did you adjust the 41.6Khz amplitude to max the signal? Once on the peak you can adjust the mass spec pot on the top of A11 to peak it. If the peak was 8na and above noise then the tube appears to be working. Anything below 4 or 5 na the tube is depleted, might be useable but STS will be terrible. If the peak is 8na then reconfigure for normal operation, in open loop mode. Turn the mod on and connect a scope to A8 J1 to observe the phase detector output. Adjust the fine and or coarse oscillator adjustments back and forth across 5Mhz. If you can see any output as you sweep through then set the osc. frequency to peak the signal. Then adjust the A3 mod and the A4 (top pot) to peak the signal. A7 gain will adjust the amplitude. Adj the osc freq. to null the signal (puts you on frequency) and see if you have any 2nd harmonic now. If so go ahead and see if it will lock. Good Luck! Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680A Loop Lock Indicator
Hi As far as I know the lock output is a CMOS output that will drive a couple of ma. There are so many variations that yours may indeed be an open collector and good to +15 volts. Bob On Sep 21, 2013, at 10:55 AM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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 NTBW50AA
I did a bit of sleuthing today about my dBc numbers. Looks like my best numbers happened (47.2 and 44.7) when the antenna was on the shortest piece of feed line, maybe 30', right above my room but well under the canopy of trees. Highest dBc I get now is in the low 40's with 150' of feed and the antenna in the clear for the most part. Also when I do the S A S thing, I never see any blue areas which should be in the 40 dBc and I see that number (40-42) all the time with the green sat numbers. What is going on here? 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] Reflections and Low Phase Noise
Hi, On 09/21/2013 07:50 PM, Tom Knox wrote: If this at first appears to be off topic read on. Having this year survived fire evacuations and most recently what has been called anything from a five to 1000 year flood here in Boulder, I have has a little time to reflect on just how lucky I was. Over the last few years I have made a few upgrades to harden my home against natural disasters. Adding sprinklers to the roof and a industrial sump pump in my basement. To say the least it paid off in a big way last week, since if my basement had flooded I would have lost my lab that I have spent several decades building. It has motivated me to finish upgrading my grounding and lightning protection with a new eye to detail. I write this post to encourage others to do the same by spending a few minutes to look for any vulnerabilities and spend a few days addressing them. Or at least upgrading insurance. For many here in Boulder lately there is nothing they could have done, but for amny other a few minutes could have saved them months of work. If I can help just one Time-Nut save his la b it is worth it. For those that have not been in Boulder, you should realize that it is just downhill from the mountains. Multiple small creeks run through Boulder as the rain poors off the Rocky Mountains, like the Flatirons that dominate the view of Boulder. Boulder really stops at the Rocky Mountains. Tom's house has one of those smaller creeks just behind it. Having seen his basement, and knowing the other opportunities, it is not strange that he take precaution. Having seen the lovely display of thundering just outside Boulder, I know what that means. Good to hear you coped OK-ish with it. Now for the good stuff, We all have our idea of what a low or Ultra Low phase noise oscillator is. For 5 and 10MHz references I usually look first at 1Hz offset then the noise floor. At 5MHz I consider 125dB @ 1Hz state of the art. But now Arcihita Hati and colleges at NIST has designed a State-of-the-Art RF Signal Generation From Optical Frequency Division that sets a new standard for low phase noise with nearly -155dB @ 1Hz for a 5MHz reference. All I want to know is when will it be available as a single chip. And how long before Magnus, TVB, and other Senior Time-Nut have a workable prototype in their labs? The NIST link is not yet active, but if you would like a copy of the paper now email me off list I will send you the paper as an attachment. I think it may also be posted on IEEE's pay to play site. Giveme :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680A Loop Lock Indicator
Hi Bob, It's rather curious. Using my handheld DVM in the diode scale, I get a reading of 448 in one direction and 458 in the other with it off and cold. In the 2K ohms scale, I get 561 and 562 ohms. Later on, I'll pop the top off again and take a pic so I can expand it and look at it. For what it's worth, my DDS board is 2 revisions earlier than the one Matthias Bopp modifies here http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%201_0.pdf; Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 3:00 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi As far as I know the lock output is a CMOS output that will drive a couple of ma. There are so many variations that yours may indeed be an open collector and good to +15 volts. Bob On Sep 21, 2013, at 10:55 AM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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] FE-5680A Loop Lock Indicator
Hi Those readings sound a lot more like a CMOS gate output than some sort of open drain / open collector discrete driver. Bob On Sep 21, 2013, at 4:43 PM, Bob Stewart b...@evoria.net wrote: Hi Bob, It's rather curious. Using my handheld DVM in the diode scale, I get a reading of 448 in one direction and 458 in the other with it off and cold. In the 2K ohms scale, I get 561 and 562 ohms. Later on, I'll pop the top off again and take a pic so I can expand it and look at it. For what it's worth, my DDS board is 2 revisions earlier than the one Matthias Bopp modifies here http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%201_0.pdf; Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 3:00 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi As far as I know the lock output is a CMOS output that will drive a couple of ma. There are so many variations that yours may indeed be an open collector and good to +15 volts. Bob On Sep 21, 2013, at 10:55 AM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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] FE-5680A Loop Lock Indicator
Hi Bob, I hooked the big voltmeter up to it, and it shows +4.2V out for about a minute, and then goes to 0. Looking on the web, it seems like I can use that to drive a 2N and put the LED and dropping resistor in the collector path with the emitter to ground? Does that sound right? Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 4:12 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi Those readings sound a lot more like a CMOS gate output than some sort of open drain / open collector discrete driver. Bob On Sep 21, 2013, at 4:43 PM, Bob Stewart b...@evoria.net wrote: Hi Bob, It's rather curious. Using my handheld DVM in the diode scale, I get a reading of 448 in one direction and 458 in the other with it off and cold. In the 2K ohms scale, I get 561 and 562 ohms. Later on, I'll pop the top off again and take a pic so I can expand it and look at it. For what it's worth, my DDS board is 2 revisions earlier than the one Matthias Bopp modifies here http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%201_0.pdf; Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 3:00 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi As far as I know the lock output is a CMOS output that will drive a couple of ma. There are so many variations that yours may indeed be an open collector and good to +15 volts. Bob On Sep 21, 2013, at 10:55 AM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reflections and Low Phase Noise
Tom, Don't forget the 'stand-by' generator to keep that pump running. If you have natural gas and can 'plant' a propane tank in the ground, you can get an automatic transfer, dual fuel, generator with an automatic transfer switch to power the entire house and automatically put the generator and transfer switch through its paces on a weekly basis. If you do this, all you will need to 'back-up' the CS standards and other 'time-nut' related equipment is a battery that will last about 10 minutes at the most. Good luck. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Knox Sent: Saturday, September 21, 2013 12:50 PM To: Time-Nuts Subject: [time-nuts] Reflections and Low Phase Noise If this at first appears to be off topic read on. Having this year survived fire evacuations and most recently what has been called anything from a five to 1000 year flood here in Boulder, I have has a little time to reflect on just how lucky I was. Over the last few years I have made a few upgrades to harden my home against natural disasters. Adding sprinklers to the roof and a industrial sump pump in my basement. To say the least it paid off in a big way last week, since if my basement had flooded I would have lost my lab that I have spent several decades building. It has motivated me to finish upgrading my grounding and lightning protection with a new eye to detail. I write this post to encourage others to do the same by spending a few minutes to look for any vulnerabilities and spend a few days addressing them. Or at least upgrading insurance. For many here in Boulder lately there is nothing they could have done, but for amny other a few minutes could have saved them months of work. If I can help just one Time-Nut save his lab it is worth it. Now for the good stuff, We all have our idea of what a low or Ultra Low phase noise oscillator is. For 5 and 10MHz references I usually look first at 1Hz offset then the noise floor. At 5MHz I consider 125dB @ 1Hz state of the art. But now Arcihita Hati and colleges at NIST has designed a State-of-the-Art RF Signal Generation From Optical Frequency Division that sets a new standard for low phase noise with nearly -155dB @ 1Hz for a 5MHz reference. All I want to know is when will it be available as a single chip. And how long before Magnus, TVB, and other Senior Time-Nut have a workable prototype in their labs? The NIST link is not yet active, but if you would like a copy of the paper now email me off list I will send you the paper as an attachment. I think it may also be posted on IEEE's pay to play site. Thomas Knox ___ time-nuts mailing 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] HP 5061A Problem
Adrian, You can use either Zeeman frequency as long as you use the corresponding A1 frequency synthesizer setting. See: http://www.febo.com/pipermail/time-nuts/2005-April/018171.html This does not matter for troubleshooting but once you want to get on frequency they need to match. Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680A Loop Lock Indicator
Yes, but put an isolation resistor between the output and the base of the transistor, something between 3K and 5K should work. The LED will light upon power on and extinguish when lock is achieved. John WA4WDL -- From: Bob Stewart b...@evoria.net Sent: Saturday, September 21, 2013 6:10 PM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi Bob, I hooked the big voltmeter up to it, and it shows +4.2V out for about a minute, and then goes to 0. Looking on the web, it seems like I can use that to drive a 2N and put the LED and dropping resistor in the collector path with the emitter to ground? Does that sound right? Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 4:12 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi Those readings sound a lot more like a CMOS gate output than some sort of open drain / open collector discrete driver. Bob On Sep 21, 2013, at 4:43 PM, Bob Stewart b...@evoria.net wrote: Hi Bob, It's rather curious. Using my handheld DVM in the diode scale, I get a reading of 448 in one direction and 458 in the other with it off and cold. In the 2K ohms scale, I get 561 and 562 ohms. Later on, I'll pop the top off again and take a pic so I can expand it and look at it. For what it's worth, my DDS board is 2 revisions earlier than the one Matthias Bopp modifies here http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%201_0.pdf; Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 3:00 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi As far as I know the lock output is a CMOS output that will drive a couple of ma. There are so many variations that yours may indeed be an open collector and good to +15 volts. Bob On Sep 21, 2013, at 10:55 AM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reflections and Low Phase Noise
For those that have not been in Boulder, you should realize that it is just downhill from the mountains. Multiple small creeks run through Boulder as the rain poors off the Rocky Mountains, like the Flatirons that dominate the view of Boulder. Boulder really stops at the Rocky Mountains. Except the creeks aren't so small when it rains hard. They have a large collection basin. I've seen this described as a 1000 year flood, but I don't know how credible that was. For something like that, the only solution is to not live in the lowlands. For those of you who haven't seen it in the news, here are some good pictures: http://tinyurl.com/lk2kuwr http://www.theatlantic.com/infocus/2013/09/historic-flooding-across-colorado/1 00591/ http://tinyurl.com/l9qkb6r http://www.theatlantic.com/infocus/2013/09/colorado-flooding-after-the-deluge/ 100594/ -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Reflections and Low Phase Noise
Looks like Colorado's version of a hurricane. I'm pretty much convinced that, no matter what you have or where you live, Mother Nature can pretty much take it all away from you without much warning using wind, fire, water, and/or earth quake. Life is about the journey, not the destination. All we can do is try to prepare. God Bless. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Saturday, September 21, 2013 7:36 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Reflections and Low Phase Noise For those that have not been in Boulder, you should realize that it is just downhill from the mountains. Multiple small creeks run through Boulder as the rain poors off the Rocky Mountains, like the Flatirons that dominate the view of Boulder. Boulder really stops at the Rocky Mountains. Except the creeks aren't so small when it rains hard. They have a large collection basin. I've seen this described as a 1000 year flood, but I don't know how credible that was. For something like that, the only solution is to not live in the lowlands. For those of you who haven't seen it in the news, here are some good pictures: http://tinyurl.com/lk2kuwr http://www.theatlantic.com/infocus/2013/09/historic-flooding-across-colorado /1 00591/ http://tinyurl.com/l9qkb6r http://www.theatlantic.com/infocus/2013/09/colorado-flooding-after-the-delug e/ 100594/ -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Space mission comes to an end becuase of a computer time tagging problem
jim...@earthlink.net said: If it gets cold enough (without power from solar cells, it won't generate enough internal heat to keep warm), it will die. That's probably what happened to Spirit on Mars. It got cold enough during the Martian winter, and with not enough solar power, enough things drifted cold enough that we couldn't get commands in. What stops working when things get cold? On Mars, the solar cells are pointed in the right direction. Why doesn't it recover when the sun comes back in the Spring? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680A Loop Lock Indicator
Hi John, Thanks for the response. I managed to cobble something up with LTSpiceIV, and get it to work. And for me, that's saying something! Here's what I wound up with: http://www.evoria.net/AE6RV/GPSstd_PLL/LED-driver.png;, where V2 is the Loop Lock Indicator. The PN shorts out the LED until it goes into lock, then the LED comes on. It does give a short pulse when power is first applied and things are equalizing. Even with a 1K resistor, the 4.2V from Lock signal is pulled down to 3V. And here's a pic of my Rb standard on it's temporary home with the LED on a scrap of breadboard: http://www.evoria.net/AE6RV/GPSstd_PLL/Rb.standard.png;. Bob From: jmfranke jmfra...@cox.net To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 6:58 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Yes, but put an isolation resistor between the output and the base of the transistor, something between 3K and 5K should work. The LED will light upon power on and extinguish when lock is achieved. John WA4WDL -- From: Bob Stewart b...@evoria.net Sent: Saturday, September 21, 2013 6:10 PM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi Bob, I hooked the big voltmeter up to it, and it shows +4.2V out for about a minute, and then goes to 0. Looking on the web, it seems like I can use that to drive a 2N and put the LED and dropping resistor in the collector path with the emitter to ground? Does that sound right? Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 4:12 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi Those readings sound a lot more like a CMOS gate output than some sort of open drain / open collector discrete driver. Bob On Sep 21, 2013, at 4:43 PM, Bob Stewart b...@evoria.net wrote: Hi Bob, It's rather curious. Using my handheld DVM in the diode scale, I get a reading of 448 in one direction and 458 in the other with it off and cold. In the 2K ohms scale, I get 561 and 562 ohms. Later on, I'll pop the top off again and take a pic so I can expand it and look at it. For what it's worth, my DDS board is 2 revisions earlier than the one Matthias Bopp modifies here http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%201_0.pdf; Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 3:00 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi As far as I know the lock output is a CMOS output that will drive a couple of ma. There are so many variations that yours may indeed be an open collector and good to +15 volts. Bob On Sep 21, 2013, at 10:55 AM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680A Loop Lock Indicator
Bob, I would bump that base resistor up a lot higher, to load the FE-5680 less. The PN has enough gain it only needs about 0.3 mA base drive to work as intended. You'd get that with a 10K base resistor. Bob LaJeunesse From: Bob Stewart b...@evoria.net To: Time Nuts time-nuts@febo.com Sent: Saturday, September 21, 2013 10:02 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi John, Thanks for the response. I managed to cobble something up with LTSpiceIV, and get it to work. And for me, that's saying something! Here's what I wound up with: http://www.evoria.net/AE6RV/GPSstd_PLL/LED-driver.png;, where V2 is the Loop Lock Indicator. The PN shorts out the LED until it goes into lock, then the LED comes on. It does give a short pulse when power is first applied and things are equalizing. Even with a 1K resistor, the 4.2V from Lock signal is pulled down to 3V. And here's a pic of my Rb standard on it's temporary home with the LED on a scrap of breadboard: http://www.evoria.net/AE6RV/GPSstd_PLL/Rb.standard.png;. Bob From: jmfranke jmfra...@cox.net To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 6:58 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Yes, but put an isolation resistor between the output and the base of the transistor, something between 3K and 5K should work. The LED will light upon power on and extinguish when lock is achieved. John WA4WDL -- From: Bob Stewart b...@evoria.net Sent: Saturday, September 21, 2013 6:10 PM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi Bob, I hooked the big voltmeter up to it, and it shows +4.2V out for about a minute, and then goes to 0. Looking on the web, it seems like I can use that to drive a 2N and put the LED and dropping resistor in the collector path with the emitter to ground? Does that sound right? Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 4:12 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi Those readings sound a lot more like a CMOS gate output than some sort of open drain / open collector discrete driver. Bob On Sep 21, 2013, at 4:43 PM, Bob Stewart b...@evoria.net wrote: Hi Bob, It's rather curious. Using my handheld DVM in the diode scale, I get a reading of 448 in one direction and 458 in the other with it off and cold. In the 2K ohms scale, I get 561 and 562 ohms. Later on, I'll pop the top off again and take a pic so I can expand it and look at it. For what it's worth, my DDS board is 2 revisions earlier than the one Matthias Bopp modifies here http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%201_0.pdf; Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 3:00 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi As far as I know the lock output is a CMOS output that will drive a couple of ma. There are so many variations that yours may indeed be an open collector and good to +15 volts. Bob On Sep 21, 2013, at 10:55 AM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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] FE-5680A Loop Lock Indicator
Thanks for the heads-up, Bob. I'll do it the next time the iron is hot. Fortunately, it's only on for about a minute or so, then there's no drive from the FE-5680A. Is 3ma really that big a deal? I know squat about CMOS gates. I guess it is pulling the voltage down by 25%, though. Bob From: Robert LaJeunesse rlajeune...@sbcglobal.net To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 9:24 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Bob, I would bump that base resistor up a lot higher, to load the FE-5680 less. The PN has enough gain it only needs about 0.3 mA base drive to work as intended. You'd get that with a 10K base resistor. Bob LaJeunesse From: Bob Stewart b...@evoria.net To: Time Nuts time-nuts@febo.com Sent: Saturday, September 21, 2013 10:02 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi John, Thanks for the response. I managed to cobble something up with LTSpiceIV, and get it to work. And for me, that's saying something! Here's what I wound up with: http://www.evoria.net/AE6RV/GPSstd_PLL/LED-driver.png;, where V2 is the Loop Lock Indicator. The PN shorts out the LED until it goes into lock, then the LED comes on. It does give a short pulse when power is first applied and things are equalizing. Even with a 1K resistor, the 4.2V from Lock signal is pulled down to 3V. And here's a pic of my Rb standard on it's temporary home with the LED on a scrap of breadboard: http://www.evoria.net/AE6RV/GPSstd_PLL/Rb.standard.png;. Bob From: jmfranke jmfra...@cox.net To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 6:58 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Yes, but put an isolation resistor between the output and the base of the transistor, something between 3K and 5K should work. The LED will light upon power on and extinguish when lock is achieved. John WA4WDL -- From: Bob Stewart b...@evoria.net Sent: Saturday, September 21, 2013 6:10 PM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi Bob, I hooked the big voltmeter up to it, and it shows +4.2V out for about a minute, and then goes to 0. Looking on the web, it seems like I can use that to drive a 2N and put the LED and dropping resistor in the collector path with the emitter to ground? Does that sound right? Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 4:12 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi Those readings sound a lot more like a CMOS gate output than some sort of open drain / open collector discrete driver. Bob On Sep 21, 2013, at 4:43 PM, Bob Stewart b...@evoria.net wrote: Hi Bob, It's rather curious. Using my handheld DVM in the diode scale, I get a reading of 448 in one direction and 458 in the other with it off and cold. In the 2K ohms scale, I get 561 and 562 ohms. Later on, I'll pop the top off again and take a pic so I can expand it and look at it. For what it's worth, my DDS board is 2 revisions earlier than the one Matthias Bopp modifies here http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%201_0.pdf; Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, September 21, 2013 3:00 PM Subject: Re: [time-nuts] FE-5680A Loop Lock Indicator Hi As far as I know the lock output is a CMOS output that will drive a couple of ma. There are so many variations that yours may indeed be an open collector and good to +15 volts. Bob On Sep 21, 2013, at 10:55 AM, Bob Stewart b...@evoria.net wrote: The instructions I got with this Rb said that you could hook an LED through a 5-10K resistor to the +15 supply and get a lock indication. I'm using a 10K resistor and the LED lights as soon as it's powered up from cold. Is the loop lock indicator circuit broken or is it just another strange option for these things? I saw on one site that if you do it this way it prevents lock, but mine seems to lock OK with or without the voltage. Bob - AE6RV ___ time-nuts mailing 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 --
Re: [time-nuts] Space mission comes to an end because of a computer time tagging problem
jim...@earthlink.net said: Then on the ground, we time tag (with an atomic clock) when the telemetry frame is received. (giving you Earth Received Time or ERT) Someone on the ground does a process of time correlation figuring out what spacecraft time corresponds to what TAI time, allowing for the various factors like the light time from spacecraft to the earth station. A friend works at the VLA. http://en.wikipedia.org/wiki/Very_Large_Array They occasionally cooperate with NASA. He told me roughly the following story. NASA wanted a second opinion on the location of one of their probes out near Jupiter or Saturn or ??? No problem. They collected some data and fed it to the computers. NASA didn't like the answer. It was way off. After the appropriate amount of head scratching, the VLA geeks figured out that this was the first time that they had used that software to look at something that was within the solar system. They fixed it to do the blue-shift corrections from nearby rather than infinity. NASA was very happy with the revised answer. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Space mission comes to an end becuase of a computer time tagging problem
On 9/21/13 6:40 PM, Hal Murray wrote: jim...@earthlink.net said: If it gets cold enough (without power from solar cells, it won't generate enough internal heat to keep warm), it will die. That's probably what happened to Spirit on Mars. It got cold enough during the Martian winter, and with not enough solar power, enough things drifted cold enough that we couldn't get commands in. What stops working when things get cold? Lots of things. Mars gets *really cold* in the winter (-50C and lower) There's an issue with plastic packages where it gets brittle. CTE mismatches cause cracks, etc. Electrolytic capacitors freeze. On Mars, the solar cells are pointed in the right direction. Why doesn't it recover when the sun comes back in the Spring? for Spirit, because of the issues with the wheel drive motors, it couldn't get into the right position to face the sun (on a south facing hillside, basically) That 10-20 degrees makes a big difference because of the cosine (angle) problem/ ___ time-nuts mailing 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] FE-5680A Loop Lock Indicator
b...@evoria.net said: Is 3ma really that big a deal? I know squat about CMOS gates. I guess it is pulling the voltage down by 25%, though. There should be something in the data sheet. 1/2 :) If you trace the signal back the next time you have it open, you might be able to figure out which data sheet to go looking for. For things like 5V CMOS signals, HC is a reasonable guess. If you look at the data sheet for a typical HC chip, it will specify Voh at a load current of 20 uA and 4 mA. That at least tells you that a 4 mA load is sensible. I'd probably use 10K because my junk box has lots of 1K and 10K, and 1K seems too small. 10K at 5V is 1/2 mA max or 1/4 mA if the output droops and we deduct some more for Vbe. How bright do you want your LED to be? (How much current?) Scan the data sheet and look for minimum Beta... Plan B: Insert a PIC/AVR/whatever-you-like. It can turn on a green LED for OK, and blink a red LED for non-locked. And the data sheet will tell you how much current you can drive. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Space mission comes to an end becuase of a computer time tagging problem
On Sat, Sep 21, 2013 at 6:40 PM, Hal Murray hmur...@megapathdsl.net wrote: What stops working when things get cold? On Mars, the solar cells are pointed in the right direction. Why doesn't it recover when the sun comes back in the Spring? They run out of power for running the battery heaters, then the battery freezes and fails. The batteries get to such a low temperature that they are unable to be charged. The rover was never designed so that it could move and operate under solar power. It is really battery powered and uses the panel for charging. This is the biggest reason the newest rover, Curiosity is powered by an RTG, not solar cells. The RTG is powered by radioactive decay. The thing makes a lot of heat and should last 15 to 20 years. Likely longer than all the moving parts like motors and so on. -- 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.
Re: [time-nuts] Reflections and Low Phase Noise
I have heard it called about everything up to a 1000 year flood. But I also heard a University of Colorado professor who monitors Boulder creek called it a twenty five year flood. In any case I was lucky. Thanks; Thomas Knox To: time-nuts@febo.com From: hmur...@megapathdsl.net Date: Sat, 21 Sep 2013 17:35:49 -0700 Subject: Re: [time-nuts] Reflections and Low Phase Noise For those that have not been in Boulder, you should realize that it is just downhill from the mountains. Multiple small creeks run through Boulder as the rain poors off the Rocky Mountains, like the Flatirons that dominate the view of Boulder. Boulder really stops at the Rocky Mountains. Except the creeks aren't so small when it rains hard. They have a large collection basin. I've seen this described as a 1000 year flood, but I don't know how credible that was. For something like that, the only solution is to not live in the lowlands. For those of you who haven't seen it in the news, here are some good pictures: http://tinyurl.com/lk2kuwr http://www.theatlantic.com/infocus/2013/09/historic-flooding-across-colorado/1 00591/ http://tinyurl.com/l9qkb6r http://www.theatlantic.com/infocus/2013/09/colorado-flooding-after-the-deluge/ 100594/ -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
