Re: [time-nuts] GPS-18, Windows, NTP & Lat Lon
How about a serial port spy/monitor program. There are some free ones like: http://www.serial-port-monitor.com/ Brian On 9/4/2013 01:30, Bob Stewart wrote: One very direct way is to find some software to sniff the com port where the GPS receiver is. I'm a Linux guy, so I can't help you on that one. Bob - AE6RV From: Jim Lux To: Discussion of precise time and frequency measurement Sent: Tuesday, September 3, 2013 7:35 PM Subject: [time-nuts] GPS-18, Windows, NTP & Lat Lon I'm looking for an easy way to get current lat lon, when you've got a GPS-18 hooked up for NTP. That is, the GPS receiver is there doing it's NTP thing, so presumably it knows where it is. If NTP is decoding the GPRMC message, it has the lat/lon in it, so how can I get that info out (in a command line utility, into a file, or some such) I don't need millisecond time accuracy.. For now the GPS is just to make sure that the time is "right". The GPGGA sentence would also do. And, I only need the GPS position once within a 30 second interval (it's not moving, I just want to know where it is). It's not like ntpd or ntpq have some handy switch that says "display current lat/lon" (which makes sense, because NTP is fundamentally time source agnostic). All of this with Windows 7. Jim - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3222/6134 - Release Date: 09/03/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Speaking of 5370s
This brings to mind the early 60's. You could go to Arrow Electronics on Long Island. The had trays of a large variety of ceramic switch wafers, switch bodies, shafts, bolts, nuts etc. You simply selected what your needed to build you MxNxP rotary switch.. Yearning for the past. Brian On 8/30/2013 14:26, Don Latham wrote: I haven't looked on mine, but can you drill a 1/4 in hole and patch in little pb switches? or patch in the common small 4-pin pcb switches? looks ugly, of course, but... Don Bob Camp Hi Don't know if the switches are compatible, but the 5334 and 5335 are a lot more common than the 5345 and 5370. For that matter I'd bet there are a bunch of same era DVM's and such that have switches that might work. Bob On Aug 30, 2013, at 2:32 AM, Christopher Brown wrote: Working on reviving a 5370B, have everything working except the switches. (multiple switches took impact damage). So, if anyone has 5370 or 5345 front switch/control board(s) they want to part with, let me know. ___ time-nuts mailing 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3211/6122 - Release Date: 08/30/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] LPRO 101 - does anyone know how much the C Field pot changes and what direction?
Hi Alan, Just did this. Less than 0.005 Hz. To really fine tune it, you need to used the C-field adjustment pin. This circuit is simple. A Linear Technology LT1236 precision 5V regulator and a 10 K linear 20+ turn pot. You can get a sample of the chip free from Linear Technology. CircuitLPRO power voltage -LT1236 POT GND || >CFIELD PIN GND On the adjustment, you tweak it and wait about 10 minutes to see what it does. Then tweak again. Do this with the LPRO in its enclosure after it has run at least a day. Regards, Brian On 8/16/2013 13:41, Alan Kamrowski II wrote: Hi Everyone, I'm going to try to calibrate my LPRO 101 to a GPS 1pps signal. Does anyone know what "one turn clockwise" of the c field adjustment pot will do to the signal in terms of ppb ? Thanks, Alan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3211/6082 - Release Date: 08/16/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3211/6082 - Release Date: 08/16/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Warped back to 1993
Hal, Is the change cumulative? In other words is one tries 2^n times, could you get there? BTW. Thanks for your advice on scopes. I finally ordered a DS1102. I had ordered a DS2072 but it would have been 4-6 weeks till arrival, if then. In the interim, I convinced myself a 2072 would have been a like trying to hold a tiger by the tail. Play with the cheaper version for learning purposes. I was also turned off by the metal heat sink holddowns popping off inside the unit. While a repair would be easy, one would void the warranty. Turns out guys have hacked the 2072 to turn it into a 2202 bandwidth et al. 73 de Brian/K3KO On 8/11/2013 17:51, Hal Murray wrote: mag...@rubidium.dyndns.org said: I'm sure that the NTP drivers can be hacked to make necessary adjustments without too much code. The code is already in there. It's got a fudge option in the config file. That was intended to fixup small offsets. I think it will work with big offsets too. 1024 weeks is 1024*7*86400 seconds. That's 0x24EA, 30 bits. It won't fit in a float if you also need to correct for a few ms, but it should work if you changed enough stuff from floats to doubles. They are likely to be doubles already. It would be fun to try. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3211/6069 - Release Date: 08/11/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 9390-55108 IRIG
Paul, You've notice this too. Steaks on the grill go from raw to well done in a few milliseconds. Brian On 8/9/2013 17:48, paul swed wrote: You just never know when you need accurate time in the basement or garage and definitely insures you don't over do the steaks on the grill. Regards Paul - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3211/6064 - Release Date: 08/09/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RS 232
There are other timing issues involved too. Many radios still use relays to switch from transmit to receive. (PIN diodes only in the more expensive ones). The radio receives a key closure but delays RF output from 8 to 20 ms or more to allow time for relay closure. This time delay becomes particularly important when one is driving a high powered amp (like 1.5 KW). It heavier relay in them need at least 8 to as much as 20ms (even when hot shotted) to go from transmit to receive. Hot switching is to be avoided at all costs. Some top of the line amplifiers do use PIN diodes too but they are not very tolerant of higher than 2:1 SWR's. In the heat of action it is easy to select the wrong antenna or put the amp in a >2:1 SWR situation. Their replacement costs are $100 and up and more than one are used. Yes there are protection circuits which help preserve them most of the time. It only takes one bad zap though. BTW latency/aural feedback issues also affect the acoustic world. Performers in locations with echos need to wear an earpiece which carries non-echo band music to not get totally confused. It is an interesting phenomena to see a performer go totally flaky because of echos. Brian On 7/27/2013 05:05, Didier Juges wrote: Most CW operators use "keyers" to generate the dits and dahs precisely. The keyer can be controlled directly by the computer or be a software Meyer or be controlled by an iambic key connected to the computer. A few operators still use straight keys like the J38 or a 'bug' like the Vibroplex. The key is the input method, or the keyboard. Some software, like the N1MM contest logging software have an embedded software keyer and also support a separate external keyer. Didier KO4BB Bob Camp wrote: Hi ….. but why route the key *through* the computer if you are generating the side tone off of RF… Bob On Jul 26, 2013, at 6:16 PM, Brian Alsop wrote: Actually computers generate probably 98% of the code during so called radio contests. During a contest weekend it is not at all unusual for individuals to make thousands of contacts. Computers automate the drudgery of sending your call thousands of times and most exchanges. However even during these contests, the manual key has to sometimes be used to provide corrections or handle situations not covered by "canned" messages. Because of the tremendous adjacent and even on frequency interference, computers have proved incapable of decoding code with the accuracy and speed of a human in real time. Brian On 7/26/2013 22:04, Bob Camp wrote: Hi There's also the time honored approach of generating the side tone off of the generated RF. In that case the latency to the transmitter would matter quite a bit. I have no idea *why* you would run the key through a computer in that case …. Bob On Jul 26, 2013, at 4:52 PM, Jim Lux wrote: On 7/26/13 12:50 PM, Didier Juges wrote: There is a difference between managing the latency (as in ensuring that sound and video are synchronized, but latency itself is acceptable) and minimizing the latency as in a Morse code keyer where the operator has to manually control the generation of elements that can be as narrow as 20mS (one dit at 60 words per minute) while getting timely aural feedback. That means you need the sound to start and stop within less than about 5 mS following the key closing and opening. It is trivial to do on a microcontroller running at 1MHz but surprisingly harder to do on a 2GHz Windows machine. It is not just a matter of time stamping the key closure, you have to get the sound system starting and stopping. Yep. although, since the propagation path is on the order of 100 milliseconds, providing feedback to the user directly from the interface works quite well (e.g. generating tones directly from the keying). The challenge is trying generate the sidetone through Windows. But really, there's no reason why you can't have a "keying box" that provides the direct side tone and sends the events to the host computer. Then the issue is more about keeping constant latency (or else the CW will be really, really hard to copy) It's not like an extra 10 milliseconds of delay between keying and the emitted RF waveform makes any difference at the other end. ___ time-nuts mailing 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3209/6023 - Release Date: 07/26/13 - No virus found in this message. Checked b
Re: [time-nuts] GPS Spoofing
If you know your LORAN has a 1/4 mile accuracy then you stay 1/2 mile away from bad things. The trouble with GPS is that it is so good, people don't use common sense and give obstacles a wide berth. Brian On 7/27/2013 04:21, Jim Lux wrote: On 7/26/13 8:45 PM, J. Forster wrote: I gather from the article, the GPS position was spoofed and the autopilot, in bringing it back to where it was supposed to be, actually took it off course. There are places where a few hundred feet makes a big difference, viz. the Costa Concordia. IMO, this is a very convincing reason for something like LORAN. I think it's a convincing argument for a captain who pays attention to the other navigation instruments and doesn't blindly follow the GPS. It's also a convincing argument that shipboard automation/autopilot/autocontrol vendors need to make more sophisticated software (which I suspect they do, particularly on 200+ foot ships.. I would imagine that there are some aspects of this demo that are contrived.) The ship making and driving business is pretty unregulated. It's all about what the owner of the ship is willing to pay (or what he needs to get liability insurance, if he wants). There's nothing even remotely like DO-178 for shipboard stuff. The folks doing stabilized oil rigs probably have sophisticated systems, but they're also using IMUs and other stuff. Ditto for high value things (oil tankers, warships). Molasses tankers? They're probably lucky to have a functioning compass and some old charts. I'm not sure, though, that looking at the big picture, whether your tax dollars are better spent on LORAN, or on some other precision navigation method or on making jam resistant GPS receivers (which do, in fact exist, and make use of things like direction of arrival of the signal..) Note that a GPS system with 3 antennas (as is common in systems that use GPS to derive attitude/orientation) would be extremely difficult to spoof, and would be VERY inexpensive to implement. Either the carrier phases and code phases are consistent for all the received signals or they're not. A jamming signal coming from the wrong direction will not have the right direction of arrival relative to the platform orientation. One wrong signal might be tolerable (multipath, etc.) but with a multi satellite fix, I suspect it would be hard to do it. Sure, one could throw up N pseudolites on a bunch of UAVs, etc., but that's getting to be a bit noticeable. For what it's worth, I don't know that LORAN has the performance to avoid a Costa Concordia type foul up (assuming they were crazy enough to do the near pass in the fog, so visual navigation didn't work) I seem to recall that LORAN had 1/4 nmi kinds of accuracy. it would get you to the channel or mouth of the harbor, but not get you into your berth. You might be familiar with the local propagation anomalies and get better accuracy with experience in your local waters. -John = I boat? The backup is a competent captain. He'd see the compass heading move and quickly disengage the autopilot. I had a boat for years I'd notice a 5 degree change. Mine was a sailboat so I'd be more sensitive to heading changes than a power boater but still the human is the backup. Most autopilots don't directly follow GPS, they use GPS to determine a heading, follow it then use GPS to detect drift and re-compute the heading. the heading would be held by a compass sensor in a low-cost setup or in a larger setup a lazer ring gyro backed up by a compass. So a spoofed GPS would cause the autopilot to "think" there was a bigger crooswnd or current and make a bigger heading change. I bet you could hijack a drone not a manned vehicle the pilot is trained to monitor the automation and he'd very quickly turn it off thinking it was broken. On Fri, Jul 26, 2013 at 8:41 AM, J. Forster wrote: Prof. Humphry from Texas just reported being able to spoof GPS in the Med and take over the nav system of a luxury yacht. He's done this before with a drone in the US. LORAN as a backup, at least? -John == ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3209/6023 - Release Date: 07/26/13 - No virus found in this message. Checked
Re: [time-nuts] RS 232
Actually the sidetone is generated in most cases by the transmitter. It can be fed into either earphones, speaker or the computer depending on what you're doing. The manual key can be connected to the computer, WINKEY box or directly to the transmitter. Connecting it to the computer or WINKEY allows one to interrupt a canned message being sent by the computer to send something else manually. ($%$#* hit the wrong message button) Brian On 7/26/2013 22:19, Bob Camp wrote: Hi ….. but why route the key *through* the computer if you are generating the side tone off of RF… Bob On Jul 26, 2013, at 6:16 PM, Brian Alsop wrote: Actually computers generate probably 98% of the code during so called radio contests. During a contest weekend it is not at all unusual for individuals to make thousands of contacts. Computers automate the drudgery of sending your call thousands of times and most exchanges. However even during these contests, the manual key has to sometimes be used to provide corrections or handle situations not covered by "canned" messages. Because of the tremendous adjacent and even on frequency interference, computers have proved incapable of decoding code with the accuracy and speed of a human in real time. Brian On 7/26/2013 22:04, Bob Camp wrote: Hi There's also the time honored approach of generating the side tone off of the generated RF. In that case the latency to the transmitter would matter quite a bit. I have no idea *why* you would run the key through a computer in that case …. Bob On Jul 26, 2013, at 4:52 PM, Jim Lux wrote: On 7/26/13 12:50 PM, Didier Juges wrote: There is a difference between managing the latency (as in ensuring that sound and video are synchronized, but latency itself is acceptable) and minimizing the latency as in a Morse code keyer where the operator has to manually control the generation of elements that can be as narrow as 20mS (one dit at 60 words per minute) while getting timely aural feedback. That means you need the sound to start and stop within less than about 5 mS following the key closing and opening. It is trivial to do on a microcontroller running at 1MHz but surprisingly harder to do on a 2GHz Windows machine. It is not just a matter of time stamping the key closure, you have to get the sound system starting and stopping. Yep. although, since the propagation path is on the order of 100 milliseconds, providing feedback to the user directly from the interface works quite well (e.g. generating tones directly from the keying). The challenge is trying generate the sidetone through Windows. But really, there's no reason why you can't have a "keying box" that provides the direct side tone and sends the events to the host computer. Then the issue is more about keeping constant latency (or else the CW will be really, really hard to copy) It's not like an extra 10 milliseconds of delay between keying and the emitted RF waveform makes any difference at the other end. ___ time-nuts mailing 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3209/6023 - Release Date: 07/26/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3209/6023 - Release Date: 07/26/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3209/6023 - Release Date: 07/26/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3209/6023 - Release Date: 07/26/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] RS 232
Actually computers generate probably 98% of the code during so called radio contests. During a contest weekend it is not at all unusual for individuals to make thousands of contacts. Computers automate the drudgery of sending your call thousands of times and most exchanges. However even during these contests, the manual key has to sometimes be used to provide corrections or handle situations not covered by "canned" messages. Because of the tremendous adjacent and even on frequency interference, computers have proved incapable of decoding code with the accuracy and speed of a human in real time. Brian On 7/26/2013 22:04, Bob Camp wrote: Hi There's also the time honored approach of generating the side tone off of the generated RF. In that case the latency to the transmitter would matter quite a bit. I have no idea *why* you would run the key through a computer in that case …. Bob On Jul 26, 2013, at 4:52 PM, Jim Lux wrote: On 7/26/13 12:50 PM, Didier Juges wrote: There is a difference between managing the latency (as in ensuring that sound and video are synchronized, but latency itself is acceptable) and minimizing the latency as in a Morse code keyer where the operator has to manually control the generation of elements that can be as narrow as 20mS (one dit at 60 words per minute) while getting timely aural feedback. That means you need the sound to start and stop within less than about 5 mS following the key closing and opening. It is trivial to do on a microcontroller running at 1MHz but surprisingly harder to do on a 2GHz Windows machine. It is not just a matter of time stamping the key closure, you have to get the sound system starting and stopping. Yep. although, since the propagation path is on the order of 100 milliseconds, providing feedback to the user directly from the interface works quite well (e.g. generating tones directly from the keying). The challenge is trying generate the sidetone through Windows. But really, there's no reason why you can't have a "keying box" that provides the direct side tone and sends the events to the host computer. Then the issue is more about keeping constant latency (or else the CW will be really, really hard to copy) It's not like an extra 10 milliseconds of delay between keying and the emitted RF waveform makes any difference at the other end. ___ time-nuts mailing 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3209/6023 - Release Date: 07/26/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3209/6023 - Release Date: 07/26/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] was RS-232,
Hi Jim, You mean to imply no commercial programs ever use "quick fixes"? It's difference between seat-of-the-pants field engineering and a theoretical pursuit. There are no humanitarian costs associated with failure so standards and formal test program and the like aren't required. Your are right it is a question of market size the $$ that can be charged for a package rather what could be with enormous effort. Many ham programs are free or essentially so. There would be no market for them if they were not. Hams are basically cheapskates. To say the programs are not sophisticated or the coders non-skilled is simply wrong. I suggest you in particular look at the free N1MM code and what it does. It does indeed use the quick fix. The other fact is that hams use their PC's for many of the everyday applications you describe as well. Nor are most hams computer hardware geeks, programmers, OS geeks (or even OS literate) or network engineers. They put their kilobucks into radios, antennas and sundry hardware. Separate computers/OS's for each piece of hardware they have simply doesn't happen often. In fact, given the array of hardware used, separate computers and OS's would likely be a nightmare. BTW, one fix for the timing problem that corrupted code timing is something called WINKEY. It is an external box. You send it ASCII characters and it sends out the perfectly timed code. It does work but has caused quite a few problems in setting it up. There is more it has to do than just the translation. Radio teletype can be done in a similar way with the equivalent of a modem. Then there are multiple antenna rotors to position, logging of contacts, antenna switch boxes, voice keyers, audio routing, networks, internet data streaming, multiple radios to control and communicate with, separate SDR's which automatically troll for stations to contact, amplifier interfaces which pretune the high power amplifier when necessary, multi monitor displays, satellite antenna tracking.. The list goes on. Having one central computer do everything is pretty much of a must for a single operator. BTW, calling it wireless isn't appropriate. There generally is a huge rat's nest of wires and cables behind the desk. Regards Brian On 7/26/2013 13:06, Jim Lux wrote: On 7/26/13 4:41 AM, briana wrote: Ever since WINxp arrived on the scene hams who send code via computer to radios via parallel, serial or usb ports (with serial port converters following) have seen the latency issue in spades. We're talking about effective baud rates less that 50. 3-4 milliseoond variable latency changes making the code nearly unreadable. The killer is that the latency changes randomly. Previous to WINXP one could do direct writes to the ports under software controlled timing. All was good. The solution for WINXP was to bypass WINDOWS handling of port data via a DLL called DLPORTIO There is a similar one for WIN7. I haven't timed how accurate it is. However 65 words per min (6 characters/second) code can be sent with no detectable timing problems. The simple act of open and closing a set of contacts at precise times now requires a huge, faxt machine, tons of software and software to work around the normal software. That's progress? no.. what it means is that you have a bad system architecture. You shouldn't be trying to do hard real time on a machine primarily designed for user interface experience and running office automation tools like word and excel. It is no more reasonable to expect a modern PC (primarily a media display device) to do hard real time control than it is to expect an iPhone to do so, or even a mainframe computer. The days are long past when a PC is basically a microcomputer with a few limited peripherals. Hams have problems because the developers have insufficient budget or resources to devote the time to writing appropriate code using the Windows media stack to get the synchronization performance desired. They're looking for the "quick fix", a'la direct port writes. Note that real time action in games works fairly well, as does keeping the video and audio synchronized in various and sundry media players, even when playing through USB connected devices. Midi sequencers run just fine with Windows. So, it's more a matter of spending the enormous amount of time needed to become facile with the entire multimedia API, all the various hooks and widgets in Windows, etc. This is a non trivial task, and one that cannot be done in spare time on the weekends for most people. You generally need to be immersed in the "windows way" of doing things (which is exceedingly different from DOS, microprocessor, or Unix) and understand how it works, and then you need to be using Windows development tools and have the appropriate libraries, etc. The Windows ecosystem is quite powerful, but it's different than other ones, so a life of Unix kernel hacking might give you the genera
Re: [time-nuts] GPS 18 behavior
Have you considered WWVB? Works fine within structures. Even though the carrier today is phase modulated one can probably glean 1 ms accuracy from it or the data transmitted. Regards Brian On 7/23/2013 14:05, Magnus Danielson wrote: On 23/07/13 05:55, Jim Lux wrote: On 7/21/13 6:42 PM, Chris Albertson wrote: I think the way to keep the sensors in sync is to use the same method they use to keep cell towers in sync. Basically each tower has a GPS receiver and also a good local oscillator. The GPS disciplines the oscillator and the timing is taken from that oscillator, not directly from the GPS. If the GPS signal is blocked the system continues normally however the oscillator may drift without the connection to GPS. Then later when the GPS is available again the oscillator is corrected. The system can run for a few days in holdover with no GPS connection. I think you were talking about a system that switches to a backup 1PPS signal. Today, I have a system with multiple modules physically connected by a cable that need to be sync'd to maybe 1 millisecond. I was thinking about using the 1pps from the GPS as the sync, if it was available all the time, even in GPS denied areas; that would make it always use the same sync from the same device, even if it's not synchronized to some external time scale. Since the GPS receiver doesn't put out the 1pps all the time, I can sync another way, and drive that sync process from the GPS if it's available. The long term system will have multiple modules separated by some distance that need to be synced and frequency disciplined, but they might have GPS, so that could be used to discipline a clock in the usual way. As a practical matter, I'm more a fan of using GPS for knowledge and adjust the output using a DDS rather than steer the oscillator, because that allows a higher Q resonator, but that's a matter of engineering details. There's also the situation where you're totally GPS denied, but that's an even more tricky problem. That is not the way to do it. The GPS should discipline a 10MHz crystal (or whatever) and then you divide that by 10,000,000 to get your 1PPS. Then when the GPS fails there is no interruption, no mode change. Such a system only needs to have access to GPS now and then. So if you have to go under a pile of concrete and loose access to the sky there is no "hiccup". This would work for the distributed system too. Your 1E-11 over 10 to 100 seconds would be met even if GPS were out for a few hours. Yes, that would do. It turns out, though, that although you could tolerate a slow drift, assuming you can figure out what it is, it makes life harder if the two modules have drifted 1E-9 relative to each other after 10 minutes. The movie-business have similar problems, so a sync-ones and keep drift low system emerged to make field recordings easier. If it would be tolerable to have a "central" transmitter, putting a PN code over a voice radio system would suffice to keep the drift fairly well kept together for this form of system. If you choose to do it on the audio channel, then you can use of the shelf radios, and replace those or re-program those as needed. Also, they are dirt cheap nowdays. 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/6013 - Release Date: 07/23/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/6013 - Release Date: 07/23/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Interesting (meaningless?) measurement.
I acquired an HP-8657B refurbished by a well regarded individual. Beautiful printout of unit's performance versus the test matrix. One thing I was interested in is how well it "locks" to an external source. The previous generator I had produced 5 -10 ns random jumps observable on a 'scope. I've seen none of that with the 8657B. The next question: So how good is the lock? The experiment was to use my HP5335A to measure time difference between the 8656B and the Rb source locking it. The HP5335A was locked to the same Rb source. This might be pushing the 5335A's ability to reliably measure time differences in the 100 ps range. The experiment produced a standard deviation of 0.27 ns at 10 MHz for a couple hour run. Each data point was a 100 sample average. Obviously the results have components from both the 5335A and 8656B. Perhaps another measurement could be made with the internal high stability oscillator in the 5335A. There is no statistically meaningful drift in mean value with time. Good, bad or meaningless? Brian - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/6013 - Release Date: 07/23/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Tboltmon AMU range
This brings up an interesting point. There is an azimuth and a weighted azimuthal display. The azimuthal display comes out essentially omnidirectional. The weighted display produces a heart shaped pattern with the heart lobes to the NE/SW and a pretty deep null due north. What weighting is used and why? Brian On 7/21/2013 06:55, "Björn" wrote: Hi Russ AMU is a Trimble invented quality unit. I once heard a professor describe it as "A Meaningless Unit". The Tbolt can change between AMU and dBc. With your range, the Tbolt has been switched to dBC, it is not showing AMUs. Approaching 50 with your high elevation SVs is excellent. You have a very good setup! If you wish to check it further, run Lady Heather with the "Signal Strength vs Az/El" plot enabled. http://www.ke5fx.com/heather/readme.htm http://www.mail-archive.com/time-nuts@febo.com/msg40567.html -- Björn I moved my Trimble bullet up the pole to have a 360 degree unobstructed view and now the AMUs for the SVs are reading in the 39-50 range. Is this too high or normal? Russ - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/6008 - Release Date: 07/21/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Interesting (meaningless?) measurement.
The standard deviation using the 5335 internal oscillator is 0.39 nS. Regards Brian On 7/23/2013 11:32, Poul-Henning Kamp wrote: In message <51ee68ce.6090...@nc.rr.com>, Brian Alsop writes: Good, bad or meaningless? On grounds of principle I will say "probably meaningless" until I see you reproduce the same number with the counter running on the internal OCXO. That said, I've done the same thing, and found numbers of the same magnitude. For additional fun: Play with the phase-angle setting on the generator :-) I acquired an HP-8657B refurbished by a well regarded individual. Beautiful printout of unit's performance versus the test matrix. One thing I was interested in is how well it "locks" to an external source. The previous generator I had produced 5 -10 ns random jumps observable on a 'scope. I've seen none of that with the 8657B. The next question: So how good is the lock? The experiment was to use my HP5335A to measure time difference between the 8656B and the Rb source locking it. The HP5335A was locked to the same Rb source. This might be pushing the 5335A's ability to reliably measure time differences in the 100 ps range. The experiment produced a standard deviation of 0.27 ns at 10 MHz for a couple hour run. Each data point was a 100 sample average. Obviously the results have components from both the 5335A and 8656B. Perhaps another measurement could be made with the internal high stability oscillator in the 5335A. There is no statistically meaningful drift in mean value with time. Good, bad or meaningless? Brian - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/6013 - Release Date: 07/23/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] LPRO 101 wanted
Hi Magnus, Thanks reply. I'm really impressed with the technical knowledge and skills of the guys on this reflector. I won't pretend that I could ever fix one. Even with 50 years of working on stuff from tubes to SMT stuff, I'll admit its beyond me. Now the physics of how it works, that's what I can understand. Looking for a working unit. Regards Brian On 7/18/2013 14:41, Magnus Danielson wrote: On 07/18/2013 04:33 PM, Brian Alsop wrote: Guys, Anybody have an unneeded LPRO-101? Yes, E-bay has a few but at prices that have increased 2.5x in a year or so. They were not interested in my "reasonable" bids. Hmm, talking about LPROs. Anybody did a full reverse engineering of one? I already have the hacked up "repair manual" with parts of the schematics. I have a bunch of LPROs and want to put them to use, but the better one understands them, the better one can fix them. 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/6001 - Release Date: 07/18/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/6001 - Release Date: 07/18/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] LPRO 101 wanted
Guys, Anybody have an unneeded LPRO-101? Yes, E-bay has a few but at prices that have increased 2.5x in a year or so. They were not interested in my "reasonable" bids. Brian - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/6001 - Release Date: 07/18/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] eLoran announcement in the UK
I find this interesting. The military is also rekindling an interest in HF communications. It seems that they are worried that satellite communications are vulnerable. A story I heard was that one fellow (a ham and book reseller) spent 10 year buying up surplus Collins 5 kW transmitters from the government. He had the warehouse space and equipment to handle heavy stuff. Now there is a run on his stock by, guess who, the military. Brian On 7/17/2013 17:06, Iain Young wrote: On 17/07/13 17:27, David wrote: Not the first time this has been mentioned but another confirmation of the GPS alternative and "eLoran stations to be rolled out across UK" http://eandt.theiet.org/news/2013/jul/eloran-rollout.cfm?utm_source=Adestra&utm_campaign=E%26T%20News%20fortinightly%20-AUTOMATION%20VERSION-%20members&utm_medium=Newsletters-E%26T%20News&utm_content=E%26T%20News%20-%20Members&utm_term=http%3A%2F%2Feandt.theiet.org%2Fnews%2F2013%2Fjul%2Feloran-rollout.cfm&utm_contact=17085095 Now this will be interesting. My -understanding- is that eLORAN is backwards compatible with LORAN-C, (So an old LORAN receiver will still receive the eLORAN signals, you just wont get the extra features [low rate data transmissions, timing built in, rather than relying on TOC etc]) Now if only they'd stop playing with Anthorn during the day at the moment, I could do some more tests. Ah well, I'll get to it later, it'll be cooler then anyway! Iain ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5998 - Release Date: 07/17/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5998 - Release Date: 07/17/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPSDO - Does it work?
Without terminating the cable in 50 ohms, you're getting reflections that the counter sees as additional peaks in time. To see much at all one needs 12 digits of resolution. Brian On 7/15/2013 20:46, Bob Stewart wrote: Hi Mark, I just tried a10 second gate, and it's still the same, though the 4.999 happens less often. Could it be related to the fact that this is a TTL signal? If I don't set the 50 ohm Z button it counts double - i.e. 10MHz. bob From: Mark C. Stephens To: Discussion of precise time and frequency measurement Sent: Monday, July 15, 2013 3:06 PM Subject: Re: [time-nuts] GPSDO - Does it work? Slow the Gate time down. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5992 - Release Date: 07/15/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5992 - Release Date: 07/15/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPDSO is working
Guys, The PIC in question was knowingly programmed "upside down" with the N option so it could talk directly to the computer without an RS232 converter. (input side suitably protected from -voltage levels) This works of most PC's which in actuality use 3.3 Volt logic in their RS232 port and input clamp highs/lows to be within the logic family limits. There are two serial port choices for a PIC in the PICAXE/BS2 compilers N and T. From the PICAXE manual. "N idles low and T idles high. When using a simple resistor interface use N (inverted) When using a MAX232 type interface use T" The bottom line is depending upon what your device is putting out and what you are talking to you may or may not need an inverter for use with the MAX232. Regards, Brian On 7/13/2013 03:10, Chris Albertson wrote: You have it 100% correct. The UT+ uses "positive" logic are the logic 1 is 5-volts but the RS-232 standard uses "negative" logic. I think the MAX232 does the conversion correctly EXCEPT if you read the RS-232 standards they use positive logic for the control signals. On Fri, Jul 12, 2013 at 7:34 PM, Bob Stewart wrote: Hi Brian, That's just strange. There are a whole lot of these MAX232 and MAX3232 devices being sold. Hmm, I'm looking at the UT+ User's Guide, and it lists the voltage levels as follows. These would imply that an inverter is necessary, right? Could it be that someone programmed your PIC upside down - i.e. using negative logic? TTL 0 V to 0.8 V = logic 0 2.4 V to 5.0 V = logic 1 RS-232 (reordered from manual to put logic 0 on top) 5 V to 15 V = logic 0 -5 V to -15 V = logic 1 Bob - AE6RV From: Brian Alsop To: Bob Stewart ; Discussion of precise time and frequency measurement Sent: Friday, July 12, 2013 9:09 PM Subject: Re: [time-nuts] GPDSO is working Hi Bob, Here is my experience. I had a PIC that output RS232 at 0-5 volt levels. It actually worked with my computer directly. When I added a MAX 232 to make the levels something like -10/+10 volts. It didn't work. That's because the MAX232 inverts the polarity. Look at the data sheet, the level converters are clearly inverters. The fix in my case was to invert the RS232 stream output by the PIC and all was fine. I'm not sure exactly what you have but a scope sorts it out quickly. 73 de Brian/K3KO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5987 - Release Date: 07/12/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPDSO is working
Hi Bob, Here is my experience. I had a PIC that output RS232 at 0-5 volt levels. It actually worked with my computer directly. When I added a MAX 232 to make the levels something like -10/+10 volts. It didn't work. That's because the MAX232 inverts the polarity. Look at the data sheet, the level converters are clearly inverters. The fix in my case was to invert the RS232 stream output by the PIC and all was fine. I'm not sure exactly what you have but a scope sorts it out quickly. 73 de Brian/K3KO On 7/13/2013 01:12, Bob Stewart wrote: Hi Brian, I don't understand. Are you saying that I need to add still more parts to get an RS-232 to TTL adapter to work? Here's the circuit for what I'm currently using, and it looks like it's inverter based. I'm not using it, because it's the only one I have and I want to keep it available for other use. http://www.scienceprog.com/wp-content/uploads/2006i/RS232_ALT/interface_schematic.gif Bob - AE6RV ____ From: Brian Alsop To: Discussion of precise time and frequency measurement Sent: Friday, July 12, 2013 7:36 PM Subject: Re: [time-nuts] GPDSO is working Max 232's invert the polarity. You have to follow with an inverting gate if the TTL stuff worked. Brian ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5986 - Release Date: 07/12/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5986 - Release Date: 07/12/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPDSO is working
Max 232's invert the polarity. You have to follow with an inverting gate if the TTL stuff worked. Brian On 7/13/2013 00:27, Chris Albertson wrote: I have a UT+ I bought a TTL-RS232 converter on eBay the converter is built into a DB-9 socket. It uses male header pins for conniption, the same kind of pins as on the UT+ Look at item # 330838910970 on eBay. It is almost exactly what I have, lots of people sell them. It is just the max232 chip but the packaging looks clean and easy to use. But as I remember I had to use at least one inverter gate. I forgot why maybe to drive the PPS or the LED I wanted to add. I don't have a VE2ZAZ board. I was using the UT+ for NTP server. My next project is to build a GPSDRO (GPS Disciplined Rubidium Oscillator) I could likely count the 10MHz output for 10,000 seconds. On Fri, Jul 12, 2013 at 10:04 AM, Bob Stewart wrote: Hi Chris, Thanks. Our setup is a bit different. My oscillator is the Trimble 34310-T and I'm using an Oncore UT+ receiver board. What are you using for your RS-232-TTL converter? I'm looking for one that will look relatively "clean" when I get it mounted on the back of this HP 37203A box.. I'm also interested in the idea of using a USB-TTL converter, but I haven't seen a decent one with the square(ish) socket, rather than the rectangular one. Bob - AE6RV From: Chris Howard To: Bob Stewart ; Discussion of precise time and frequency measurement Sent: Friday, July 12, 2013 11:32 AM Subject: Re: [time-nuts] GPDSO is working Hi Bob. My configuration is: - HP 10811-60111 10 Mhz oscillator - Trimble Resolution-T GPS card - VE2ZAZ controller board - homebrew power supplies - RS232 switchable between GPS and VE2ZAZ controller - little e-bay puck GPS antenna on the top of an 8' post outside my window. I did get the software for the Resolution-T from the Trimble site and did a site survey. My software settings for the VE2ZAZ controller board are: S: 00E1 (a few seconds more than one hour) F: 01(for this osc the fine adj is not useful) L: B1 H: 10 W: c8 N: 0A O: 01 X: 02 M: 01 I've had the thing running for about a year. It took a while to figure out a bad solder joint in my oscillator that made the DAC voltage ineffective. Since it's been running right I have had the opportunity to compare it to a cesium standard and I'm happy. There is also a mailing list for the VE2ZAZ controller where you might find more info: http://mailman.qth.net/mailman/listinfo/gps_standard Chris w0ep ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5986 - Release Date: 07/12/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Nortel Trimble thunderbolt
On 7/6/2013 04:06, Chris Albertson wrote: But I think in this case it is just a three wire connection but still there is room for errors like for example is one of them a TTL level and the other RS-232. Some times you can mix the two, sometimes not. This is a valid point. My radio will accept TTL and RS232 level signals on the same port. (I should say 0 and 5 volts as the logic levels up to -15/+15) However the polarity of them has to be proper. Most people run a TTL level "RS232" signal (e.g. from a PIC) through a MAX232 and think their done. In fact, the MAX232 inverts the polarity. The TTL signal polarity must be changed for it all to work. Regards, Brian - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5969 - Release Date: 07/06/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] BPSK decoder for WWVB
Yes, according to: www.jks.com/wwvb.pdf Brian On 7/3/2013 20:48, Rob Kimberley wrote: I assume you mean MSF... Sent from Samsung Mobile Original message From: Brian Alsop Date: To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] BPSK decoder for WWVB Apparently this modulation scheme is less prone to "jammers". There is is British station which "jams" east coast WWVB. Brian/K3KO On 7/3/2013 18:00, Tim Shoppa wrote: Potentially the BPSK encoding ought to offer much better decoding here on the East Coast of US. Many of the commercially available, pre-BPSK WWVB consumer clocks didn't sync so well in the summertime due to high noise levels. Tim N3QE - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5961 - Release Date: 07/03/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5961 - Release Date: 07/03/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5961 - Release Date: 07/03/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] BPSK decoder for WWVB
Apparently this modulation scheme is less prone to "jammers". There is is British station which "jams" east coast WWVB. Brian/K3KO On 7/3/2013 18:00, Tim Shoppa wrote: Potentially the BPSK encoding ought to offer much better decoding here on the East Coast of US. Many of the commercially available, pre-BPSK WWVB consumer clocks didn't sync so well in the summertime due to high noise levels. Tim N3QE - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5961 - Release Date: 07/03/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Glonass Payload lost... (Rob Kimberley)
$200 million for these three. http://uk.reuters.com/article/2013/07/02/uk-russia-space-rocket-idUKBRE96103Y20130702?feedType=RSS&feedName=worldNews Brian On 7/2/2013 16:03, Dan Kemppainen wrote: Note to self, Not getting on any Russian made rockets any time soon. At least the rockets were unmanned, and hopefully no one on the ground was hurt! Sounds like this isn't the first time this happened, and it isn't the first time they lost three Glonass birds. Wonder how much money was lost in just the 6 satellites blown up thus far. It may be a while before I start looking for any glonass receiver hardware. Dan On 7/2/2013 10:27 AM, time-nuts-requ...@febo.com wrote: http://www.bbc.co.uk/news/science-environment-23140665 Rob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5956 - Release Date: 07/02/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5956 - Release Date: 07/02/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Smithsonian Time/Nav Exhibit
Indeed. The Link A-12 sextant I have is shown on the page "Navigation at War" To take a reading, one rotates the plastic circular disk and puts the object in the bubble. The markings are made on that disk as well. At 12 o'clock, one can make out the "pencil" device that marks it. A thumb activated mechanism moves the pencil to mark the disk. On the left are the silver the battery compartment cylinder and the illumination cylinder for the the bubble. Hidden in this picture are the sun/haze filters and the movable "mirror" that changes angle as the circular disk is rotated. The main readout is in half degree increments. A vernier allows one to read down to 1' of arc. One minute equates to one nautical mile of longitude or latitude at the equator. Woe be the navigator that doesn't erase all markings on the disks before the next readings. Running out of pencil lead isn't recommended. Brian On 7/1/2013 16:04, Robert Atkinson wrote: For those of us who would have to navigate a long way, there is a on-line http://timeandnavigation.si.edu/ Robert G8RPI. From: Jim Lux To: Discussion of precise time and frequency measurement Sent: Monday, 1 July 2013, 13:56 Subject: [time-nuts] Smithsonian Time/Nav Exhibit I had a chance to go through the Time and Navigation exhibit at the National Air and Space Museum last week. From a "time" standpoint, there's probably not much there that time-nuts don't know already, but it's kind of cool to see cleaned up examples of equipment from days gone by. (there's an old cesium beam from NIST on display, and a Symmetricom cesium turned on and counting, but also a lot of old GPS stuff... lots of Rb and Cs for space) Quite a lot of the exhibit space was devoted to the problem of air navigation, which, now that I've seen the exhibit, I can understand what challenge it was. Over centuries, folks had figured out how to navigate on ships and on land, but those are inherently slow moving, so you can do things like take multiple sextant sights and reduce them. But planes move fast, so you don't have as much time to do it. It took real guts to be the navigator in the little cockpit out front of the plane, taking sights with your body out in the wind. And the poor fellow who was sucked out of a plane when taking sights standing on his seat and the astrodome blew out. It was interesting to see how many different schemes were used for (mostly radio based) nav in airplanes over a fairly short time. Low Frequency DF, A/N Ranges, VOR, LORAN, etc. I didn't see Omega. They have an inertial nav unit there from a sub, but not much explanation of how inertial nav works. They talk about the DSN (and actually have a 4 bay rack of the old time/frequency distribution gear on display), but not much discussion on exactly how we do navigation for deep space. ___ time-nuts mailing 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5952 - Release Date: 06/30/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5952 - Release Date: 06/30/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Smithsonian Time/Nav Exhibit
I have a WWII vintage octant used by my Dad to do celestial navigation when ferrying bombers to England during the war. It was also used when Colonial Airlines flew from NYC to Bermuda in the late 40's. Still have it. It really is possible to navigate with the beastie. The airplane turbulence induced jerks were not an obstacle. If fact, the motions may have been less vexing than use of a hand held sextant on a ship. The octant has a drum and pencil arrangement. When you take a fix, it marks the drum. You take a series of measurements of the same object, write down the start and finish times. It has a lighted bubble to provide the horizon. Thus one has a horizon day and night. Insert a new drum and do another object. Go back to your desk and do the various lines of position, advanced for time difference between object fixes. (Generally an eyeball average of the various pencil lines and use of the midpoint time would suffice.) The plotting of them results in a fix. The tables used for data reduction were much abridged from the normal several volume set--reflecting the less precise nature of the measurement technique. It contained something like 50 7"x10" pages compared to the normal 5+ pounds of books. Let's face it, if you get a fix within 5-20 miles, that's good enough if you're trying to find England. Finding the coast of North America would have been even easier on the return trip. However, the trip back was via boat. Dead reckoning using speed and direction is tough on the great circle route due to crazy magnetic compass deviations. The celestial nav fixes at a minimum flagged that "something was wrong" if the dead reckoning and celestial fixes disagreed a lot. I learned celestial navigation (on land) using this octant before getting a sextant. You can use it on land because it has a built-in horizon. Neat piece of history. Brian On 7/1/2013 12:56, Jim Lux wrote: I had a chance to go through the Time and Navigation exhibit at the National Air and Space Museum last week. From a "time" standpoint, there's probably not much there that time-nuts don't know already, but it's kind of cool to see cleaned up examples of equipment from days gone by. (there's an old cesium beam from NIST on display, and a Symmetricom cesium turned on and counting, but also a lot of old GPS stuff... lots of Rb and Cs for space) Quite a lot of the exhibit space was devoted to the problem of air navigation, which, now that I've seen the exhibit, I can understand what challenge it was. Over centuries, folks had figured out how to navigate on ships and on land, but those are inherently slow moving, so you can do things like take multiple sextant sights and reduce them. But planes move fast, so you don't have as much time to do it. It took real guts to be the navigator in the little cockpit out front of the plane, taking sights with your body out in the wind. And the poor fellow who was sucked out of a plane when taking sights standing on his seat and the astrodome blew out. It was interesting to see how many different schemes were used for (mostly radio based) nav in airplanes over a fairly short time. Low Frequency DF, A/N Ranges, VOR, LORAN, etc. I didn't see Omega. They have an inertial nav unit there from a sub, but not much explanation of how inertial nav works. They talk about the DSN (and actually have a 4 bay rack of the old time/frequency distribution gear on display), but not much discussion on exactly how we do navigation for deep space. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5952 - Release Date: 06/30/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5952 - Release Date: 06/30/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Quartz crystal aging and applied voltage
Remember when WWII arrived, crystals were of poor quality and not in great supply. The quartz crystal materials were all imported from South America and contained impurities. They had the nasty habit of abruptly changing frequency or drifting. They also stopped oscillating when humidity got high. Imagine yourself in the jungle calling for support during WWII and the transmitter goes dead due to the crystal. Something had to be done. This was solved quickly by growing "pure" crystals and developing the manufacturing process to do so. We've come a long way baby. Regards Brian On 6/30/2013 23:04, Bob Camp wrote: Hi On Jun 30, 2013, at 2:44 PM, Magnus Danielson wrote: Hi Bob, On 06/30/2013 06:30 PM, Bob Camp wrote: Hi Ummm…. e…. not so much. Ions in the lattice are part of the crystal structure. When you "move" them by sweeping you put stress on the quartz. That stress may take a *long* time to relax out. Since there is now a defect in the lattice (where the ion was) the stress may be relieved by an ion moving back to that location. Quartz is swept to reduce it's radiation sensitivity. That's a big deal if you are going to put the oscillator in outer space or if you expect to need to use it when unexpected bright lights appear in the sky. Neither one is likely to be of interest in a typical basement lab. The levels involved also would drive you to radiation harden the rest of the oscillator circuit, not just the crystal. There have been a series of papers on various influences on crystals. If the blank is an SC, it can be tuned by an applied DC voltage. Many precision parts have a DC short across the resonator for this reason. In that case, you would not see anything to drive an ion anyway. NIST have been using this effect for precision phase modulations. I don't agree that swept crystal has not been talked about. It is mentioned all over the precision crystal papers, it's there if you look for it. It however does not make much sense to discuss it for us, since we usually deal with complete oscillators and only rarely work with single crystals, and in that case very rarely of the quality where swept crystals occurs. There is definitely more to it than sweeping the crystal. Thanks Bob for the extra insight. The way sweeping works, won't a number of additional runs help to re-melt the crystal and help "ironing out" the dislocations in the crystal? That's not the way it's done. One pass under bias, pull the ions to the edges. Cut off the edges. If you re-melt and re-grow the crystal you get a whole new batch of ions from the growing process. Bob 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 mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5951 - Release Date: 06/30/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5951 - Release Date: 06/30/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Regulator choices
Maybe I read the original posting wrong but I think this thread has departed greatly from the original posting. What I thought the posting said: 1) The already present transformer can produce ~20 V DC unregulated at sufficient current. 2) The desire was to have a 12 V regulated at somewhat greater than 1 amp. Though it wasn't raised in the first posting. A clean, non-switching supply was desirable for the poster. Thus, it isn't a case of attaching one regulator in series with another Regards Brian On 6/30/2013 14:43, Charles P. Steinmetz wrote: A three-terminal regulator (3TR) comprises (i) a voltage reference, (ii) an error amp, and (iii) a current amplifier. There is no need to duplicate the voltage reference or the error amp just because you need more current. In fact, they can only lead to problems with current sharing and/or oscillation. If the need is simply more current, add an external pass device. It may not be quite as easy as piling on more 3TRs (i.e., it takes a little thought), but at the several-ampere level it will almost certainly be cheaper. In many cases, the design is already done -- there are hundreds, if not thousands, of example circuits in manufacturers' app notes, which are easily found on the Web. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5950 - Release Date: 06/29/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5950 - Release Date: 06/29/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Regulator Choices
If you are in the US (maybe elsewhere) you can request two free samples. Regards, Brian On 6/29/2013 04:12, Perry Sandeen wrote: Wrote: Consider using a LT1083 7.5 Amp regulator. Well it is $14 each. The LM 1084 5 Amp 1s $2.43 each Hefty premium for an extra 2.5 Amps. If one needs greater than 5 amps, the LM 1084 data sheet shows how to easily parallel 2 or 3. What’s in your wallet? Regards, Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5947 - Release Date: 06/28/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5947 - Release Date: 06/28/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] +12 Volts 1A (plus a bit) supply?
AArg, that is LT1083 On 6/27/2013 19:55, Brian Alsop wrote: Consider using a LT0183 regulator. You can get two samples free from Linear Technologies. It's good for 7.5 amps and will not need much of a heat sink. A few resistors and caps are required to set the voltage up to 12 volts. Another way is via a string of series diodes. Regards, Brian On 6/27/2013 18:32, Chris Albertson wrote: You mean you have to many volts for a 12V regulator to drop> That's easy to fix, use a resister in series. Make the resister par of an RC filter and cleaner power in the process. I use a plug-in power brink from an old notebook computer. I think mine outputs 15V and then this gets dropped to 12V and 5V with a RC filter and regulators. On Thu, Jun 27, 2013 at 10:39 AM, Bob Stewart wrote: I'm using an HP 37203A case (half size) for my GPSDO project, but the output from the transformer is just too high to get +12V @ 1A to power the OCXO from a simple regulator. So, what are people using for quick and dirty 12V 1+A power supplies? I'm not in love with the idea of using a wall wart, but I could look the other way. Does anyone know of a small, cheap, quiet switching module I could use for this? 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5945 - Release Date: 06/27/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5945 - Release Date: 06/27/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5945 - Release Date: 06/27/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] +12 Volts 1A (plus a bit) supply?
Consider using a LT0183 regulator. You can get two samples free from Linear Technologies. It's good for 7.5 amps and will not need much of a heat sink. A few resistors and caps are required to set the voltage up to 12 volts. Another way is via a string of series diodes. Regards, Brian On 6/27/2013 18:32, Chris Albertson wrote: You mean you have to many volts for a 12V regulator to drop> That's easy to fix, use a resister in series. Make the resister par of an RC filter and cleaner power in the process. I use a plug-in power brink from an old notebook computer. I think mine outputs 15V and then this gets dropped to 12V and 5V with a RC filter and regulators. On Thu, Jun 27, 2013 at 10:39 AM, Bob Stewart wrote: I'm using an HP 37203A case (half size) for my GPSDO project, but the output from the transformer is just too high to get +12V @ 1A to power the OCXO from a simple regulator. So, what are people using for quick and dirty 12V 1+A power supplies? I'm not in love with the idea of using a wall wart, but I could look the other way. Does anyone know of a small, cheap, quiet switching module I could use for this? 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3204/5945 - Release Date: 06/27/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] tube GPS receivers - delay memory
No. I'd say the electronics is several years more advanced. Not the same company. However, the idea and construction is essentially the same. 73 de Brian/K3KO On 6/25/2013 18:23, Mike Naruta AA8K wrote: Could this be one of them Brian? Mike - AA8K On 06/24/2013 06:58 AM, Brian Alsop wrote: Interesting you should mention this. One summer job had me working at a company that made acoustic delay line memories. Interesting beasties. You stuck the data in at one end . The output was connected back to the input to recirculate the data. One wound the magnetic wire in a flat rectangular box. A torsional mode was used rather than push/pull. A maximum of about 50 milliseconds of memory was possible. A special near zero temperature coefficient wire was used as the medium. One used either return to zero or non-return to zero data formats. NRZ logic doubled the memory. Part of the job involved laying out PCB's by hand for the electronics. IC's were just coming on the scene. RTL logic was the only thing available. For military applications "flat packs" were used. Through hole IC's were used for everybody else. Interesting that flat packs disappeared for about 20 years until SMT became the rage. The company eventually died due to lack of suitable wire and other memory advances. Brian ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5940 - Release Date: 06/25/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5940 - Release Date: 06/25/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Measuring speed of light or reproducing a metre
You need to know the wavelength. You can get that from a diffraction grating without any knowledge of the speed of light. Brian On 6/24/2013 21:56, Jim Lux wrote: On 6/24/13 5:21 AM, Brian Alsop wrote: The time issue was effectively eliminated by the Michaelson-Morley interferometer. One used a monochromatic light and an array of mirrors which split the light in opposite directions around the track. The two beams were recombined and an interference pattern resulted. One counted the number interference fringes passing by while moving one mirror in one path. Knowing the number of fringes, wavelength of light and the mirror movement, one could compute c. There are easier ways to measure wavelength of an EM wave (Young's double slit experiment, for instance), or measuring the voltage along a transmission line carrying a reflected wave. BUT, then, an interferometer (or melted marshmallows in the microwave oven) tells you the wavelength of the EM radiation. But you need to know the frequency of that signal in order to calculate c from that measurement. and we're back to the "what can be done simply to measure time/frequency" (I guess.. it's all really arbitrary.. a meter is so many wavelengths of the light from a Krypton lamp) htt ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5937 - Release Date: 06/24/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5937 - Release Date: 06/24/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Measuring speed of light or reproducing a metre
The time issue was effectively eliminated by the Michaelson-Morley interferometer. One used a monochromatic light and an array of mirrors which split the light in opposite directions around the track. The two beams were recombined and an interference pattern resulted. One counted the number interference fringes passing by while moving one mirror in one path. Knowing the number of fringes, wavelength of light and the mirror movement, one could compute c. http://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment Actually used one of these in a physics lab in about 1962. Produces a quite reasonable estimate of c. Other methods could be used to accurately know the wavelength of light. The other experiments to measure the gravitational constant G were equally interesting. The real reason for the interferometer was to try and detect the effect of the "aether" which light was supposedly propagated in. To everyone's surprise, there was no detectable "aether". Brian On 6/24/2013 11:26, Jim Lux wrote: On 6/23/13 10:48 PM, DaveH wrote: Something a bit similar was first published by Nick Hood in 2007. Here is a copy: http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_p056. shtml Here is Nick's website: http://cullaloe.com/ Some people use marshmallows. Dave the only problem is that you don't have a very accurate measurement of the microwave oven frequency and the mode pattern isn't very "sharp". So this might get you 1 sig fig. Granted, most folks only use 1 sig fig 3E8 m/sec, but that's just a happenstance since c happens to be close to a round number. And that gets back to another time-nuts kind of question.. How accurately can you measure length and time? (in a science demo sort of way.. without getting a Rb or GPSDO, etc.) For most school age kids, the sources of time available are fairly lengthy (e.g. 1 second ticks from wwv by phone, stopwatches built into iphones, etc.) Tape measures and meter sticks are readily available. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5936 - Release Date: 06/24/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5936 - Release Date: 06/24/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] tube GPS receivers
On 6/24/2013 01:44, Jim Lux wrote: Lots of rotating drum memory and acoustic delay lines were used back then. Interesting you should mention this. One summer job had me working at a company that made acoustic delay line memories. Interesting beasties. You stuck the data in at one end . The output was connected back to the input to recirculate the data. One wound the magnetic wire in a flat rectangular box. A torsional mode was used rather than push/pull. A maximum of about 50 milliseconds of memory was possible. A special near zero temperature coefficient wire was used as the medium. One used either return to zero or non-return to zero data formats. NRZ logic doubled the memory. Part of the job involved laying out PCB's by hand for the electronics. IC's were just coming on the scene. RTL logic was the only thing available. For military applications "flat packs" were used. Through hole IC's were used for everybody else. Interesting that flat packs disappeared for about 20 years until SMT became the rage. The company eventually died due to lack of suitable wire and other memory advances. Brian - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5936 - Release Date: 06/24/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] tube GPS receivers
On 6/23/2013 14:40, Bob Camp wrote: Hi AC137 doesn't ring any bells. True tube core (no solid state at all) isn't something that was dimensioned in K words. A couple hundred words was pretty big stuff. "Quite a bit" of core done that way is a lot of tubes. As the number of tubes goes up, the time to failure comes down….. hours … minutes … who knows. Bob Yeah, it gets to be like the cross country aircraft races in the 20's. The mechanic had to fly with the pilot. (The MTBF of many of the engines used was measured in hours.) If necessary he had to climb out on the cowling while in flight to change plugs and fix whatever possible without landing. What would OSHA say about that? Needless to say future generations will probably find lots of aircraft spark plug artifacts in their digs. Brian/K3KO - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5932 - Release Date: 06/22/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Oscillator temperature compensation
"Drift quite a bit" is a matter of what century you are in. Don't forget in this era, fine calibration marks on most receivers were 5 KC, if you were lucky. They would drift only 20 KHz/hour, if you were lucky. Receiver bandwidths were 10 KC. Drifting 1 KC on AM transmit would hardly be noticed. On CW, you'd have to find the station in the RX you were talking to after a brief period of transmit. The station drifted out of the receiver pass band in the 40 or so seconds of transmit. Things have changed. I sent back a radio master oscillator that was supposed to drift only +/- 5Hz per day because it had a range of +/-15 Hz. Regards, Brian On 6/21/2013 12:56, Bob Camp wrote: Hi At that frequency, the crystal is likely some sort of bar cut rather than an AT. If the transmitter has no oven / heater around the crystal, it will indeed drift quite a bit. Bob On Jun 21, 2013, at 12:09 AM, Joseph Gray wrote: This is not strictly Time Nuts, but it is about a crystal oscillator that needs some temperature compensation, or something. Please ignore this posting if you like. In fact, so as not to clutter up the list, it would be best to email me directly about this. I have an old AM transmitter that has three 6AL11 compactrons. The crystal is a fundamental, cut for 660 KHz. I don't have a schematic for this thing, but I believe that one half of one 6AL11 is used for the oscillator. The problem is, the frequency decreases as the rig warms up. It will eventually stabilize, but the final frequency is over 200 Hz low. Not as good as it should be. I think the original specification was well under half of that. I have replaced the electrolytic caps. The others are mostly silver/mica with a few ceramics. I checked all of the resistors and only found one that was out of tolerance (I replaced it).Three NOS tubes were installed. There are no tunable components in the oscillator section. Only the output section has anything tunable. I know that there are many Amateurs on the list and I'm sure many know more about old tube rigs than I do. Does anyone have a suggestion as to what the trouble might be? Joe Gray W5JG ___ time-nuts mailing 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5929 - Release Date: 06/21/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5929 - Release Date: 06/21/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] WWVB remodulator seems to work fine on 3 V But
Reminds me of the FT-243 xtal controlled transmitter Novice days. Xtals of the frequency you wanted were hard to come by. We would grind xtals a bit on a bed of very fine abrasive to raise their frequency. The other trick was taking a pencil and adding graphite to the xtal faces to lower it's frequency. You couldn't add too much or it would stop oscillating-- forever. Never did understand the forever part. Removing the graphite didn't bring it back to life. Brian K3KO On 6/18/2013 23:57, paul swed wrote: As I have discovered the 8170 expects 60 Khz. Going to 3 V dropped the xtal freq 1 hz low and the 8170 does not lock. Good to know and I suspect a bit hard to fix. But will look into it. Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5920 - Release Date: 06/18/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5920 - Release Date: 06/18/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Something else has gotten much worse with switchers- RFI. While most of them are supposed to be "approved" in some way, about 80% of them generate unacceptable levels of RF interference. So do the supplies for the under the counter LV lamps and LED drivers. How was the 80% figure arrived at? Bought 10 supplies and tested across the 1.8 -30 MHz range by looking at pan adapter output attached to my ham radio. 8/10 produced unacceptable noise levels. Then there is the worst of all-- most plasma display TV's. They can wipe out blocks with their noise. Then there are the treadmills, high efficiency air conditoners and now washing machines. Anything with a variable speed DC motor... Regards, Brian On 6/17/2013 13:56, Jim Lux wrote: On 6/17/13 5:33 AM, Peter Gottlieb wrote: The current distortion from simple transformer-rectifier-capacitor power supplies contains a lot of third harmonic content. In a 3 phase system (as are all distribution systems for commercial and industrial) the third harmonic ADDS in the neutral, or creates circulating currents in a delta configuration. These currents, as you mention, can get very large and were the cause of many transformer explosions in cities as these power supplies became common. The transformer designs had to be improved, but the PFC supplies make a big difference. How many of you have looked at the power line waveform, especially in an industrial or commercial area? Doesn't look much like a sine wave, does it? So it's pretty funny to see audiophile outlets (http://www.dedicatedaudio.com/power_outlets). Peter The "PFC correction" stuff is, as you say, more about harmonic content reduction than actual power factor. The rules on the current waveform came in as part and parcel of the power factor rules, so maybe it was just a simpler way to explain it? It's all about looking more like a resistive load. The US National Electrical Code was updated about 15-20 years ago because of the neutral current problem. In light industrial, office, running 208/120Y is very common, the old codes allowed the neutral to be smaller than the phase conductors (assuming that the loads would be resistive and all balance out) but with all those capacitive input filters, the current in the neutral got pretty high and there were fears of fires and overheating (I don't know if there were actually any fires, but poor voltage stability and heating of distribution hardware is probably more likely). Certainly, the utilities weren't wild about the harmonic currents, so they almost certainly agitated for the change as well. (Imagine you're a utility servicing a multitenant building, but the tenants all have single phase service, which the utility spreads around the three phases. The utility has the problem of the distribution transformers and the triplex currents. And, in fact, this harmonic thing is hard to fix in distribution equipment anyway (some set of tuned traps?) so it does make sense to push it to the user. The issue also arises with fluorescent and other gas discharge lighting, particularly with "electronic" ballasts (e.g. switchers). The old "magnetic" ballasts (basically just a big inductor) sort of inherently act as a low pass filter, and solve the harmonic problem by getting warm. And, they'd have a very lagging power factor, but a fairly fixed on that you could compensate with capacitor banks. As folks transitioned to the newer ballasts, the non-sinusoidal current problem probably got worse. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5917 - Release Date: 06/16/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5917 - Release Date: 06/16/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt GPS "APP" updates?
Thanks. On 6/14/2013 23:22, Arthur Dent wrote: "The two apparently were manufactured within 3 months of one another." I'd say 9 months. The firmware revision from 2.2 to 3.0 is the 3 months you mentioned and from what I could gather ( which may or may not be correct) mainly changed the algorithm for handling carryover and unless you're without a lock for a long time you'll not notice any real difference. I wouldn't worry about it. -Arthur - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5911 - Release Date: 06/14/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Thunderbolt GPS "APP" updates?
Current Thunderbolt GPS shows: APP: 2.2 11 Mar 2002 GPS: 10.2 14 Nov 2001 Mfg: 07 June 2002 I previously owned another APP:3.0 27 June 2002 GPS: 10.2 14 Nov 2001 Mfg: 21 Mar 2003 The two apparently were manufactured within 3 months of one another. Some questions: 1) What is APP and what does it do? 2) Would it be possible to put APP 3.0 on the current unit? If so would cause problems or provide any benefits? Regards Brian - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5911 - Release Date: 06/14/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap 9.8Mhz Sa.22c's
Will it run on watch batteries? On 6/2/2013 22:03, Chris Albertson wrote: If you start with your 9.830400MHz Rb and then divide that by 300 you get 32768Hz. 32768Hz is what is used in watches and clocks and PC mainboards for time of day clocks. So the maybe the best use of the Rb is to make a really good wall clock. Use it to replace a cheap watch timing crystal. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3184/5877 - Release Date: 06/02/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cheap 9.8Mhz Sa.22c's
Manual is here and discusses PC interface and how to set to factory settings. I think it may be a simple matter to bring back 10MHz. http://www.rdrelectronics.com/skip/feb/SA22c.pdf On 6/2/2013 18:13, Robert Atkinson wrote: Hi Magnus, According to the datasheet 10MHz is a standard output. The Manual say you can change the factory setting using SSIP ( Symmetricom Serial Interface Protocol). Unless of couse the particular units have been restricted. I don't thnik so as both the factory set frequency and 10MHz are coved by the standard unit. Robert G8RPI. From: Magnus Danielson To: time-nuts@febo.com Sent: Sunday, 2 June 2013, 19:06 Subject: Re: [time-nuts] Cheap 9.8Mhz Sa.22c's On 06/02/2013 07:52 PM, Mark C. Stephens wrote: These are 9.8304Mhz, is possible to move them to 10Mhz? http://www.ebay.com/itm/Symmetricom-SA-22c-9-8304MHz-Precision-Rubidium-Oscillator-5V-and-15V-NICE-/261223397404 I looked at it, and no. They change the core oscillator, and then you can alter the divide power of 2 but other than that no luck. This limits their uses outside the intended usage. 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 mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3184/5875 - Release Date: 06/01/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3184/5875 - Release Date: 06/01/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Faster/more automated Rb oscillator calibration
This is probably nothing new, but looking over the archives, I didn't see it posted in the last couple years I've had an LPRO-101 Rb oscillator for several years. It was first calibrated using the phase shift vs time method using a GPSDO as the reference. Stopwatch and oscilloscope. Ugh! Needless to say it got really time consuming with full cycle times of 1000's of seconds. I've revisited this and come up with something much simpler but more importantly automated. Simply input the GPSDO oscillator signal into channel A and the Rb oscillator into channel B of my HP 5335A counter. Tell it to determine the time difference (1ns resolution). Send these differences to a file via HPIB. The neat thing is that one can quickly see trends over a fraction of a cycle. When done, let it run all night and look at the output. The output is a sawtooth or reverse sawtooth ranging from 0 to 100 ns. One can compute the time difference between any points of adjacent teeth to determine a full cycle's phase shift. Alternately one can look at part of a sawtooth for a quick estimate. It's neat to see that I'm starting to get triangles rather than a sawtooth-- meaning the two are essentially at the same frequency and drifting about each other. BTW the Rb oscillator bias of 1 mHz present two years ago was still there and had changed only 0.2 mHz over the intervening time. Regards, Brian - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3184/5870 - Release Date: 05/30/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
