Re: [time-nuts] Used Spectracom
Hi ….. and MSF does not do the BPSK rock and roll. That *should* ultimately improve your ability to reject MSF. How much improvement will depend on how fast the fade rate is when you are trying for a signal. Bob On Jan 16, 2013, at 6:45 PM, paul swed paulsw...@gmail.com wrote: Well the noise level is rising all the cfls and such. But what nails me is MSF out of england. I can see the confusion it causes in the signal chain. BPSK it actually creates offsets depending on the signal strength. Then we all face the noise in the summer. Regards Paul On Wed, Jan 16, 2013 at 4:09 PM, Hal Murray hmur...@megapathdsl.net wrote: Quite odd my 8170 absolutely will not lock How far are you from the transmitter? What is EMI like in your area? Years ago, Dave Mills was ranting about WWVB becoming useless in his area (MD) because of EMI. I think he traced part of the problem to welding machines at a nearby factory. I'll try to track down more info if people are curious. I'm sure it's archived out there somewhere. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] MASER at room temperature
Interesting info about a new developed Maser working at room temperature: http://www.nature.com/nature/journal/v488/n7411/full/nature11339.html timeok ___ time-nuts mailing 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] Used Spectracom
I have two 'cheap' WWVB 'Atomic Clocks', both of which say they are 'locked' and are about 2 minutes apart. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Burt I. Weiner Sent: Wednesday, January 16, 2013 2:34 PM To: time-nuts@febo.com Subject: [time-nuts] Used Spectracom I'm not sure what the status of the new modulation scheme is at the moment, but my Spectracom 8170 is still keeping good time. That's about all I use it for anymore - a clock in the rack. It says it's locked. Burt, K6OQK Behalf Of Joseph Gray Subject: [time-nuts] Used Spectracom I find it amusing the number of Spectracom WWVB receivers that are on ebay lately. With the prices being asked, it looks like everyone is trying to dump these on the unsuspecting and make a killing on obsolete equipment. If they were dirt cheap, I'd probably pick one up. If you could wire in an external standard, it would still be useful for the phase comparator. At the listed prices, they can keep them. Joe Gray W5JG Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] More GPS troubles
If the GPS receiver hardware itself is integrated then it would require a separate firmware update which may not be possible. I know one of my more recent Garmin receivers has separate firmware for the integrated GPS receiver and the unit as a whole. On Thu, 17 Jan 2013 09:22:55 -0500, Bob Camp li...@rtty.us wrote: Hi Most cheap GPS's these days have user friendly firmware update capability. That's been true for quite a while. I'd be amazed if the higher end stuff didn't make updates an easy thing. Bugs in GPS code are not exactly uncommon. The real issue is the need to get the GPS code patched for this kind of thing. Without nutty articles that alarm the marketing department, the work will never get any sort of priority. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] More GPS troubles
On 1/17/13 6:22 AM, Bob Camp wrote: Hi Most cheap GPS's these days have user friendly firmware update capability. That's been true for quite a while. I'd be amazed if the higher end stuff didn't make updates an easy thing. Bugs in GPS code are not exactly uncommon. The real issue is the need to get the GPS code patched for this kind of thing. Without nutty articles that alarm the marketing department, the work will never get any sort of priority. But is there *really* a need to patch for this..(as opposed to the other bugs that are on the list) Consider you're using GPS as a time reference in a mission critical application. You've already got to have some holdover capability. Do you think someone could set up one of these jammers, jam your GPS, and keep doing it for long enough to extend you past your max holdover time? If you're that critical, you need geographically dispersed receivers anyway (struck by lightning?) In the example of the high accuracy reference networks.. they're *networks* and they are designed so that individual nodes can fail. Spoofing attacks, by their nature, can really only attack one receiver at a time even if the spoof signal covers a long distance(because only for the chosen victim do all the signals line up just right). So now you're talking about N jammers for N receivers, and the cost of your jamming attack is rising. Someone who wanted to deny the use of the network would be better served by sending someone out with aluminum foil/paint to cover the radome of the stations. Or a cutting torch and sawzall. (tougher to do and a bit more obvious than commanding an array of jamming systems from your underground lair) ___ time-nuts mailing 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] More GPS troubles
Since the Arbiter showed no ability to compare the settings to internal clock settings, it suffered permanent damage when it was exposed to the exploit. Permanent damage? As in components failed? No, I think a factory reset would restore it to function. You've apparently missed some of the details in the article; they specifically discussed this point. On many of these devices the corruption was to permanent storage. One GPS receiver had a permanent divide-by-zero bug, even after reboots, because the corrupt satellite elements were stored permanently. It's possible that there is no way to update the firmware at this point, because the device does not stay running long enough. (I've bricked one or two pieces of embedded hardware this way myself over the years ;). It would not surprise me if a hard factory reset would not erase the satellite orbital elements, since they're so important to correct GPS operation. Another GPS receiver stored the GPS Week Rollover count in permanent storage, with no way to reset it. Force this device to perform a week rollover, and it is useless unless you leave it switched off for 20 years. Sure these devices are still repairable, but the expertise required means, at the very least, ship it back to the factory... So few programmers write code with malicious activity in mind. Even dedicated security software developers have a hard time thinking about every possible threat! And couple that with the pressure to ship now... -- Harald ___ time-nuts mailing 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] More GPS troubles
On Thu, 17 Jan 2013 07:08:20 -0800, Jim Lux jim...@earthlink.net wrote: On 1/17/13 6:22 AM, Bob Camp wrote: Hi Most cheap GPS's these days have user friendly firmware update capability. That's been true for quite a while. I'd be amazed if the higher end stuff didn't make updates an easy thing. Bugs in GPS code are not exactly uncommon. The real issue is the need to get the GPS code patched for this kind of thing. Without nutty articles that alarm the marketing department, the work will never get any sort of priority. But is there *really* a need to patch for this..(as opposed to the other bugs that are on the list) Consider you're using GPS as a time reference in a mission critical application. You've already got to have some holdover capability. Do you think someone could set up one of these jammers, jam your GPS, and keep doing it for long enough to extend you past your max holdover time? If you're that critical, you need geographically dispersed receivers anyway (struck by lightning?) Two of the attack examples disabled the GPS receivers, one rebooted continuously until a hard reset to erase the nonvolatile memory and the other permanently returned invalid date and timing information, even after the short term spoofing signal was removed. Only minutes or tens of minutes were needed for the attacks. In the example of the high accuracy reference networks.. they're *networks* and they are designed so that individual nodes can fail. Spoofing attacks, by their nature, can really only attack one receiver at a time even if the spoof signal covers a long distance(because only for the chosen victim do all the signals line up just right). So now you're talking about N jammers for N receivers, and the cost of your jamming attack is rising. These low level spoofing attacks involved changing the satellite ephemeris, satellite almanac, or GPS epoch so they would work against multiple receivers simultaneously. Someone who wanted to deny the use of the network would be better served by sending someone out with aluminum foil/paint to cover the radome of the stations. Or a cutting torch and sawzall. (tougher to do and a bit more obvious than commanding an array of jamming systems from your underground lair) That would be cheaper at least for now. ___ time-nuts mailing 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] More GPS troubles
Hi A lot of gear has holdover in the 8 to 24 hour range. If the attack broke the receivers (as in some sort of NV storage corruption), you would need to drive out and replace the gizmos in that time frame. Inventory and tech manpower likely is set up for lightning events (a dozen maybe) rather than a whole city is down sort of thing. On the stuff I'm familiar with, there is indeed a cycle back to the mother ship sort of fix for major issues. Been there, done that. It is very much a pain, and that's why field firmware upgrades are a popular feature even in embedded devices. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Jim Lux Sent: Thursday, January 17, 2013 10:08 AM To: time-nuts@febo.com Subject: Re: [time-nuts] More GPS troubles On 1/17/13 6:22 AM, Bob Camp wrote: Hi Most cheap GPS's these days have user friendly firmware update capability. That's been true for quite a while. I'd be amazed if the higher end stuff didn't make updates an easy thing. Bugs in GPS code are not exactly uncommon. The real issue is the need to get the GPS code patched for this kind of thing. Without nutty articles that alarm the marketing department, the work will never get any sort of priority. But is there *really* a need to patch for this..(as opposed to the other bugs that are on the list) Consider you're using GPS as a time reference in a mission critical application. You've already got to have some holdover capability. Do you think someone could set up one of these jammers, jam your GPS, and keep doing it for long enough to extend you past your max holdover time? If you're that critical, you need geographically dispersed receivers anyway (struck by lightning?) In the example of the high accuracy reference networks.. they're *networks* and they are designed so that individual nodes can fail. Spoofing attacks, by their nature, can really only attack one receiver at a time even if the spoof signal covers a long distance(because only for the chosen victim do all the signals line up just right). So now you're talking about N jammers for N receivers, and the cost of your jamming attack is rising. Someone who wanted to deny the use of the network would be better served by sending someone out with aluminum foil/paint to cover the radome of the stations. Or a cutting torch and sawzall. (tougher to do and a bit more obvious than commanding an array of jamming systems from your underground lair) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Spectracom problems - was, used Spectracom...
Paul, I don't know if this will be of any help for your particular situation, but several years ago I had a problem where my Spectracom 8170 would not lock. I checked and found that I had good, clean signal at the input spigot and the voltage going to the antenna was clean and correct. After being patient with him for plenty of time, I finally broke down and called Spectracom and reached someone in service. What he said to me was: There's a board with 4 electrolytics on it. Change the electrolytics and he'll be fine. (This is not the receiver board) I did and my 8170 started working again. In fact, he was locking up and staying locked better than he had in all his previous life with me. A few years later, and for some reason that escapes me now, I shot-gunned the entire receiver with new, high quality electrolytics. I do not use him as a frequency standard, only for a fancy-shmancy clock. As far as how well he keeps time these days; he agrees with my two DATUM 9390-52054 receivers as best as my eyes jumping between the three of them can see. By the way, speaking of my two 9390's, since I replaced the Caritronics switching power supply module inside with an external Cisco ADP-30RB, both are working fine and seem happy around 1E-12 and a DAC of about 29000. Burt, K6OQK Burt I don't know what to say at all but the bpsk signal does a number to my 8170. So all I can do is scratch my head. Lucky you. Regards Paul. On Wed, Jan 16, 2013 at 7:01 PM, Burt I. Weiner b...@att.net wrote: Paul, I just went out to my shoppe and looked. Mine is locked and has been for most of the day, with two green lights. Some time ago I added a meter to the front panel that I connected to one of the test points. It's currently fairly steady except for the normal dips in carrier strength. About this time of day it usually starts to go nuts because of the Diurnal shift. I'm in Glendale, CA, just north of Downtown Los Angeles. My WWVB antenna is a ferrite rod type in a PVC tube. It's been laying by the side of the house on the ground for over 15 years. That's where I've always gotten the cleanest signal - found that out when we re-roofed the house. Burt, K6OQK Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] FTS Cesium parts units on eBay
Hi, I've placed a couple FTS 4060 parts units on ebay if anyone has an interest! Thanks, Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] WWVB clocks no longer lock (Was: Used Spectracom)
At about the time WWVB announced switching the format, two of my clocks - identical SkyScan units bought at about the same time 10 or so years ago suddenly stopped synchronizing, too. If just one of these clocks had a problem, I would chalk it up to a random failure - but two of them? One of these clocks is in my ham shack, next to a different model clock (one displays UTC, the other local) and this other clock hasn't missed a beat while the other is on the wall, well away from any noisemaker like a switcher or a CFL. I've actually swapped these clocks and neither one is happy. I've also put a different brand clock in its place and it maintains synchronization just fine. I've checked for noisemakers (switching supplies) and found a noisy one - and then quieted it down with added filtering, but even before I did this it hadn't affected a clock only a few feet away from it! The *only* time that these clocks lock up is when I first install the battery, but from then on they claim to be locked, but are drifting away from proper time. For one of these, I popped the cover and found the trace with the WWVB time code from the die-mounted receiver chip and it looks pretty clean: No stuttering is apparent, but I didn't make any attempt to time every type of mark or space to verify its timing. The fact that it synchronizes just once is puzzling - as is the fact that just this particular model is now unhappy: Was even a minor change made to the AM portion of the code? I could imagine that a too-narrow bandpass filter could slightly affect the timing of the pulses as the phase flipped, but even if this were the case, why does it always synchronize just the one time and then never again? 'Tis a puzzlement... 73, Clint KA7OEI J.L. Trantham wrote: I have two 'cheap' WWVB 'Atomic Clocks', both of which say they are 'locked' and are about 2 minutes apart. Joe ___ time-nuts mailing 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 clocks no longer lock (Was: Used Spectracom)
After reading the 'antenna on the ground' comment and being suspicious of the 'upstairs' clock, I brought it down stairs, placed new batteries, and sat it on the window ledge with the antenna 'broadside' to the west. I then went to the shop to putz around for a while. After about an hour, I came back to discover it had 'locked' (although EST instead of CST) and was 'dead on' with the other, 'downstairs', clock. I made the changes to the display needed and it is still 'right on'. Must have been an ongoing signal issue, battery issue, or an interfenence issue. The 'upstairs' clock is oriented east/west and sits high on the wall, over my office computer which is on most of the time. No other source of interference except winter and solar storms. We'll see. I'll move it back 'upstairs' and continue the 'watch'. It is troubling that it continued to give a 'locked' indication when, clearly, it was not. I may have to put a TBolt in my office. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Clint Turner Sent: Thursday, January 17, 2013 2:36 PM To: time-nuts@febo.com Subject: [time-nuts] WWVB clocks no longer lock (Was: Used Spectracom) At about the time WWVB announced switching the format, two of my clocks - identical SkyScan units bought at about the same time 10 or so years ago suddenly stopped synchronizing, too. If just one of these clocks had a problem, I would chalk it up to a random failure - but two of them? One of these clocks is in my ham shack, next to a different model clock (one displays UTC, the other local) and this other clock hasn't missed a beat while the other is on the wall, well away from any noisemaker like a switcher or a CFL. I've actually swapped these clocks and neither one is happy. I've also put a different brand clock in its place and it maintains synchronization just fine. I've checked for noisemakers (switching supplies) and found a noisy one - and then quieted it down with added filtering, but even before I did this it hadn't affected a clock only a few feet away from it! The *only* time that these clocks lock up is when I first install the battery, but from then on they claim to be locked, but are drifting away from proper time. For one of these, I popped the cover and found the trace with the WWVB time code from the die-mounted receiver chip and it looks pretty clean: No stuttering is apparent, but I didn't make any attempt to time every type of mark or space to verify its timing. The fact that it synchronizes just once is puzzling - as is the fact that just this particular model is now unhappy: Was even a minor change made to the AM portion of the code? I could imagine that a too-narrow bandpass filter could slightly affect the timing of the pulses as the phase flipped, but even if this were the case, why does it always synchronize just the one time and then never again? 'Tis a puzzlement... 73, Clint KA7OEI J.L. Trantham wrote: I have two 'cheap' WWVB 'Atomic Clocks', both of which say they are 'locked' and are about 2 minutes apart. Joe ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] How far can I push a crystal?
I've got to make a very clean 10.0594... MHz VCXO for a redo of one of my old circuits. I previously used a 10 MHz ceramic resonator, which was easy enough to push around in frequency. Of course, I have a couple dozen of those somewhere, but can't find them now that I need them again. I figured I'd just pull the ones out of the old circuit, but since I did find a whole bunch of 10 MHz quartz crystals, I'd like to revisit whether I can push one of those that far with decent results. As I recall, the results of my previous experiments in doing this were less than satisfactory, which is why I went with the ceramics. This would be a change of 60 kHz out of 10 MHz, or 0.6 percent - a helluva lot for a crystal. The frequency will be exactly phase locked to a reference. It doesn't need to have extremely high in-circuit Q or long-term stability - just tunable to that magic number - the PLL will do the rest. A conventional varicap circuit will provide the VCO-ness, while the tuning range just needs to be enough to accommodate drift and the initial setting. The power gain element will be a 74HC04 or 74HC86 section. The PLL reference will be 59.4... kHz - way above the necessary loop BW. Has anyone successfully pushed a quartz crystal that far off, with reliable (still sort of a sharp resonance) operation and no spurious modes? Any ideas? If this isn't practical, I'll just go back to the ceramic resonator (which worked just fine), but I'd like to settle it once and for all. Ed ___ time-nuts mailing 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] How far can I push a crystal?
Ed Breya wrote: I've got to make a very clean 10.0594... MHz VCXO for a redo of one of my old circuits. I previously used a 10 MHz ceramic resonator, which Forget about it. This is well beyond even the lunatic fringe of pulling. Rick ___ time-nuts mailing 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] How far can I push a crystal?
You'll never pull a crystal that far without grinding :). Regards, Tom - Original Message - From: Ed Breya e...@telight.com To: time-nuts@febo.com Sent: Thursday, January 17, 2013 6:38 PM Subject: [time-nuts] How far can I push a crystal? I've got to make a very clean 10.0594... MHz VCXO for a redo of one of my old circuits. I previously used a 10 MHz ceramic resonator, which was easy enough to push around in frequency. Of course, I have a couple dozen of those somewhere, but can't find them now that I need them again. I figured I'd just pull the ones out of the old circuit, but since I did find a whole bunch of 10 MHz quartz crystals, I'd like to revisit whether I can push one of those that far with decent results. As I recall, the results of my previous experiments in doing this were less than satisfactory, which is why I went with the ceramics. This would be a change of 60 kHz out of 10 MHz, or 0.6 percent - a helluva lot for a crystal. The frequency will be exactly phase locked to a reference. It doesn't need to have extremely high in-circuit Q or long-term stability - just tunable to that magic number - the PLL will do the rest. A conventional varicap circuit will provide the VCO-ness, while the tuning range just needs to be enough to accommodate drift and the initial setting. The power gain element will be a 74HC04 or 74HC86 section. The PLL reference will be 59.4... kHz - way above the necessary loop BW. Has anyone successfully pushed a quartz crystal that far off, with reliable (still sort of a sharp resonance) operation and no spurious modes? Any ideas? If this isn't practical, I'll just go back to the ceramic resonator (which worked just fine), but I'd like to settle it once and for all. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
Forget about it. This is well beyond even the lunatic fringe of pulling. So how far can I pull a crystal? Does it depend upon the cut or anything that turns into price? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
My friend Karl-Heinz DJ7NN has dragged/jerked/teared/wrenched crystals even more (what is the most nasty description of pulling a quartz crystal?) - if need be, he opens it and strikes a brush over it to carefully grind some material, what makes it oscillating a little faster. If you've ground too much, make a stroke with a pencil on it and it will oscillate slower. But the aging... Ok, the drawback is, you won't get a very clean signal... In my humble opinion, as Ed told before: forget about it. Volker Am 18.01.2013 00:59, schrieb Rick Karlquist: Ed Breya wrote: I've got to make a very clean 10.0594... MHz VCXO for a redo of one of my old circuits. I previously used a 10 MHz ceramic resonator, which Forget about it. This is well beyond even the lunatic fringe of pulling. Rick ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
If you need a very clean signal - what would mean, stable (and accurate) you'll have to purchase one. There are manufacturers that do the job for, say, 30 Dollars? if it is a normal cut. If you like to get a crystal for a specific temperature to build your own oven (to achieve a very stable frequency) you can use an SC-cut - what is propably much more expensive. Volker Am 18.01.2013 01:16, schrieb Hal Murray: Forget about it. This is well beyond even the lunatic fringe of pulling. So how far can I pull a crystal? Does it depend upon the cut or anything that turns into price? ___ time-nuts mailing 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] How far can I push a crystal?
Hi You can always use a crystal as a capacitor in just about any oscillator circuit. The question becomes at what point does it stop doing anything other than behave like a capacitor. The accurate way to figure this out is to know the motional capacitance of the crystal. From that and the C0 you can do some modeling and see what you get. More simple answer - anything past about 0.1% is a bit silly even with an easy to pull crystal. If you have very modest goals, 0.3 or 0.4% is possible. If your goals are modest, a VCO might also do just as well. Bob On Jan 17, 2013, at 7:16 PM, Hal Murray hmur...@megapathdsl.net wrote: Forget about it. This is well beyond even the lunatic fringe of pulling. So how far can I pull a crystal? Does it depend upon the cut or anything that turns into price? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
Here an example manufactorer in my country: http://www.quarztechnik.com/eng/hochfrequentequarze.html or http://www.icmfg.com/ Am 18.01.2013 01:31, schrieb Volker Esper: If you need a very clean signal - what would mean, stable (and accurate) you'll have to purchase one. There are manufacturers that do the job for, say, 30 Dollars? if it is a normal cut. If you like to get a crystal for a specific temperature to build your own oven (to achieve a very stable frequency) you can use an SC-cut - what is propably much more expensive. Volker Am 18.01.2013 01:16, schrieb Hal Murray: Forget about it. This is well beyond even the lunatic fringe of pulling. So how far can I pull a crystal? Does it depend upon the cut or anything that turns into price? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
Hi Ed, I seriously doubt you will be able to pull the 10 MHz crystal tht far off. International Crystal Manufacturering (ICM) http://www.icmfg.com/ still makes crystals for a reasonable amount (about $25) cut to order. That may be far easier than all the time you would spend bending and pushing things around trying stretch components. BillWB6BNQ Ed Breya wrote: I've got to make a very clean 10.0594... MHz VCXO for a redo of one of my old circuits. I previously used a 10 MHz ceramic resonator, which was easy enough to push around in frequency. Of course, I have a couple dozen of those somewhere, but can't find them now that I need them again. I figured I'd just pull the ones out of the old circuit, but since I did find a whole bunch of 10 MHz quartz crystals, I'd like to revisit whether I can push one of those that far with decent results. As I recall, the results of my previous experiments in doing this were less than satisfactory, which is why I went with the ceramics. This would be a change of 60 kHz out of 10 MHz, or 0.6 percent - a helluva lot for a crystal. The frequency will be exactly phase locked to a reference. It doesn't need to have extremely high in-circuit Q or long-term stability - just tunable to that magic number - the PLL will do the rest. A conventional varicap circuit will provide the VCO-ness, while the tuning range just needs to be enough to accommodate drift and the initial setting. The power gain element will be a 74HC04 or 74HC86 section. The PLL reference will be 59.4... kHz - way above the necessary loop BW. Has anyone successfully pushed a quartz crystal that far off, with reliable (still sort of a sharp resonance) operation and no spurious modes? Any ideas? If this isn't practical, I'll just go back to the ceramic resonator (which worked just fine), but I'd like to settle it once and for all. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] WWVB clocks no longer lock (Was: Used Spectracom)
Issue is any system that phase locked will not and then not decode Mobile so can't go into detail Paul Wb8tsl On Thursday, January 17, 2013, Clint Turner wrote: At about the time WWVB announced switching the format, two of my clocks - identical SkyScan units bought at about the same time 10 or so years ago suddenly stopped synchronizing, too. If just one of these clocks had a problem, I would chalk it up to a random failure - but two of them? One of these clocks is in my ham shack, next to a different model clock (one displays UTC, the other local) and this other clock hasn't missed a beat while the other is on the wall, well away from any noisemaker like a switcher or a CFL. I've actually swapped these clocks and neither one is happy. I've also put a different brand clock in its place and it maintains synchronization just fine. I've checked for noisemakers (switching supplies) and found a noisy one - and then quieted it down with added filtering, but even before I did this it hadn't affected a clock only a few feet away from it! The *only* time that these clocks lock up is when I first install the battery, but from then on they claim to be locked, but are drifting away from proper time. For one of these, I popped the cover and found the trace with the WWVB time code from the die-mounted receiver chip and it looks pretty clean: No stuttering is apparent, but I didn't make any attempt to time every type of mark or space to verify its timing. The fact that it synchronizes just once is puzzling - as is the fact that just this particular model is now unhappy: Was even a minor change made to the AM portion of the code? I could imagine that a too-narrow bandpass filter could slightly affect the timing of the pulses as the phase flipped, but even if this were the case, why does it always synchronize just the one time and then never again? 'Tis a puzzlement... 73, Clint KA7OEI J.L. Trantham wrote: I have two 'cheap' WWVB 'Atomic Clocks', both of which say they are 'locked' and are about 2 minutes apart. Joe __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Spectracom problems - was, used Spectracom...
Tnx hav data Trvling On Thursday, January 17, 2013, Burt I. Weiner wrote: Paul, I don't know if this will be of any help for your particular situation, but several years ago I had a problem where my Spectracom 8170 would not lock. I checked and found that I had good, clean signal at the input spigot and the voltage going to the antenna was clean and correct. After being patient with him for plenty of time, I finally broke down and called Spectracom and reached someone in service. What he said to me was: There's a board with 4 electrolytics on it. Change the electrolytics and he'll be fine. (This is not the receiver board) I did and my 8170 started working again. In fact, he was locking up and staying locked better than he had in all his previous life with me. A few years later, and for some reason that escapes me now, I shot-gunned the entire receiver with new, high quality electrolytics. I do not use him as a frequency standard, only for a fancy-shmancy clock. As far as how well he keeps time these days; he agrees with my two DATUM 9390-52054 receivers as best as my eyes jumping between the three of them can see. By the way, speaking of my two 9390's, since I replaced the Caritronics switching power supply module inside with an external Cisco ADP-30RB, both are working fine and seem happy around 1E-12 and a DAC of about 29000. Burt, K6OQK Burt I don't know what to say at all but the bpsk signal does a number to my 8170. So all I can do is scratch my head. Lucky you. Regards Paul. On Wed, Jan 16, 2013 at 7:01 PM, Burt I. Weiner b...@att.net wrote: Paul, I just went out to my shoppe and looked. Mine is locked and has been for most of the day, with two green lights. Some time ago I added a meter to the front panel that I connected to one of the test points. It's currently fairly steady except for the normal dips in carrier strength. About this time of day it usually starts to go nuts because of the Diurnal shift. I'm in Glendale, CA, just north of Downtown Los Angeles. My WWVB antenna is a ferrite rod type in a PVC tube. It's been laying by the side of the house on the ground for over 15 years. That's where I've always gotten the cleanest signal - found that out when we re-roofed the house. Burt, K6OQK Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
Hi Mouser shows 16 items tighter than +/- 20 ppm accuracy. Six of them are in stock and less than $1 in single piece quantities. The cheapest is 39 cents. Bob On Jan 17, 2013, at 7:38 PM, WB6BNQ wb6...@cox.net wrote: Hi Ed, I seriously doubt you will be able to pull the 10 MHz crystal tht far off. International Crystal Manufacturering (ICM) http://www.icmfg.com/ still makes crystals for a reasonable amount (about $25) cut to order. That may be far easier than all the time you would spend bending and pushing things around trying stretch components. BillWB6BNQ Ed Breya wrote: I've got to make a very clean 10.0594... MHz VCXO for a redo of one of my old circuits. I previously used a 10 MHz ceramic resonator, which was easy enough to push around in frequency. Of course, I have a couple dozen of those somewhere, but can't find them now that I need them again. I figured I'd just pull the ones out of the old circuit, but since I did find a whole bunch of 10 MHz quartz crystals, I'd like to revisit whether I can push one of those that far with decent results. As I recall, the results of my previous experiments in doing this were less than satisfactory, which is why I went with the ceramics. This would be a change of 60 kHz out of 10 MHz, or 0.6 percent - a helluva lot for a crystal. The frequency will be exactly phase locked to a reference. It doesn't need to have extremely high in-circuit Q or long-term stability - just tunable to that magic number - the PLL will do the rest. A conventional varicap circuit will provide the VCO-ness, while the tuning range just needs to be enough to accommodate drift and the initial setting. The power gain element will be a 74HC04 or 74HC86 section. The PLL reference will be 59.4... kHz - way above the necessary loop BW. Has anyone successfully pushed a quartz crystal that far off, with reliable (still sort of a sharp resonance) operation and no spurious modes? Any ideas? If this isn't practical, I'll just go back to the ceramic resonator (which worked just fine), but I'd like to settle it once and for all. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
Bob, are you saying they have 10.059 MHz crystals? I've never seen one anywhere, or anything even close. Ed Hi Mouser shows 16 items tighter than +/- 20 ppm accuracy. Six of them are in stock and less than $1 in single piece quantities. The cheapest is 39 cents. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
HI Sorry, I mis-read the original post. Bob On Jan 17, 2013, at 8:09 PM, Ed Breya e...@telight.com wrote: Bob, are you saying they have 10.059 MHz crystals? I've never seen one anywhere, or anything even close. Ed Hi Mouser shows 16 items tighter than +/- 20 ppm accuracy. Six of them are in stock and less than $1 in single piece quantities. The cheapest is 39 cents. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] How far can I push a crystal?
Maybe I should clarify what I meant by pushing the crystal frequency. I meant only using various topologies and electronic components in the associated circuitry, that would detune it from its natural resonance far enough to reach the new frequency, and still have it be sort of a narrow-bandwidth crystal oscillator - not doing any mechanical changes to the crystal element itself. Since the ceramic resonators seem to work well, and can be pushed (or pulled?) fairly far away by proper selection of the associated component values, I was wondering how far quartz crystals can reasonably go. I encounter this situation often - needing an oddball frequency, but preferring to use common or standard parts. The nominal choices in ceramic are quite limited, while in crystals, there are many more - but few ever seem to land at or near enough to a frequency I need. The only thing I have thought of so far is to maybe add some series R to drop the crystal Q, so broadening the resonance, and just dragging it up by extra series C, but at some point there's no point to even having the crystal there at all. I'm just trying to figure out what's possible and reasonable. I know that I can get any custom frequency by spending enough money, but that takes the challenge and fun out it sometimes. Ed ___ time-nuts mailing 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] How far can I push a crystal?
Having just adjusted a crystal oscillator at 10.715 MHz, I would hazard a guess that the most one can easily pull a crystal of nominal frequency around 10 MHz would be of the order of +/-1 kHz. Certainly not 60 kHz. dr ___ time-nuts mailing 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] How far can I push a crystal?
Ed Breya wrote: Maybe I should clarify what I meant by pushing the crystal frequency. I meant only using various topologies and electronic components in the associated circuitry, that would detune it from its natural resonance far enough to reach the new frequency, and still have it be sort of a narrow-bandwidth crystal oscillator - not doing any mechanical changes to the crystal element itself. Since the ceramic resonators seem to work well, and can be pushed (or pulled?) fairly far away by proper selection of the associated component values, I was wondering how far quartz crystals can reasonably go. I Since you asked: You can get something like a range of 0.1% by resonating out the holder capacitance with a shunt inductor. You then put this assembly in series with an inductor and varactor. If you want to get into the lunatic fringe, you use a high Q inductor wound on Fair-Rite 61 or 67. Now you can seriously pull the crystal below its resonant frequency. How far you can go depends on the Q of the inductor. I am not sure if you can also pull it above, but even if you could, there are spurious resonances up there that could get you. The lunatic fringe might get you .2 or .3%, still not .6%. You'll definitely take a hit in temperature stability and phase noise with high pulling. If you don't have experience with VCXO's, you will find the circuit design quite challenging. It wasn't clear if you needed a 10.05944 MHz VCXO, or just a source at that frequency. There a lots of one chip synthesizers that could generate that frequency as I'm sure you know. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
Bernd Neubig wrote: A parallel inductor for compensation of the static capacitance C0 does not help much at 10 MHz, because such a coil, which resonates out a 6 pF capacitance has an internal winding capacitance, which is larger than 6 pF. So you would need a coil which has a self-resonance of slightly above 10 MHz. Actually, a parallel inductor helps a lot and is essential for getting a large pulling range. Modern surface mount coils have a self capacitance of a fraction of a pF, not 6 pF, and in any event, you can always find an inductor that is resonant when combined with the crystal. The nominal value of this inductor may be considerably less than the calculated value, but there is always some value of inductor that works. This was true even in the through hole era. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How far can I push a crystal?
Thanks all, for the feedback on this issue. In summary, I got these points out of the discussion on crystals: 1. The correct terminology is pulling the frequency. 2. Getting beyond about a few hundred ppm from the nominal frequency ranges from very difficult to pointless. 3. It's easier to pull down than up. It looks like it would not be worth fooling around with crystals, so I'll just use the ceramic resonators. By the way, I just tonight managed to reach the correct geological layer of stuff out in the garage, and found the missing 10 MHz resonators, and a whole tray of other parts that were in reserve for completing this project from a couple of years ago. For the curious: The 10.059... MHz is made by a PLL using the 59.... kHz reference, which is 10.7 MHz divided by 180. The 10.7 MHz is a from another VCXO (which can use a standard crystal, ceramic resonator, or ceramic IF filter - easy) that's phase locked to a 10 or 1 MHz reference, using two fixed dividers. The 10.059... MHz is used as the reference for a phase locked microwave brick oscillator, using n=120, to make 1207.1333... MHz, which is exactly one-third of 3621.4 MHz, the low-band upconversion IF of the HP8566B spectrum analyzer. The 1207.1333... MHz is harmonically mixed (m=3) with the first LO of the SA to produce the tracking signal centered in the passband of the SA. All of this is built into the modified carcass of an HP8443A tracking generator, originally built for older SA models. Using the new stuff, plus parts of the 8443A, the net result is a 50 kHz to 250 MHz tracking generator, with power up to +10 dBm, leveled within about 1 dB, and with 130 dB step attenuator range - very nice for low RF and baseband work. The 10.059... MHz is only one of many frequencies that could be multiplied by various n-values to give the same result, but it was chosen because it was very close to a standard frequency available in ceramic resonators, high enough that n didn't need to be too large, and it could be synthesized with a very simple PLL system. I had all of this built and running, but I had made the fatal engineering mistake of putting way too much stuff in too small a space. Space was tight, so I squeezed the entire LF control system and synthesizers into one small can, and necessarily optimized for minimum IC package count. Then I found that there was too much crosstalk between virtually all the signals in the box, so there was too much phase noise to work at 300 Hz and less IFBW. The problems were irreversible - sharing IC packages for multiple signal processing was an especially bad move. After many hours of rearranging signal paths, adding shielding and grounds, and changing topologies, I concluded that I had to rebuild it the right way. So here I am. The two main frequencies will be generated in separate boxes, and no ICs will contain multiple signals that aren't being processed together. This time I'll get it right, and finally wrap it up. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
