Re: [time-nuts] REF osc distribution.
Hi It may be a language issue, but the datasheet does not present this amplifier very well. I wondered about the specification for squarewave input TTL 3.3V TTL is 5V. What is the slew rate of the amplifier? It's specified to 50MHz, will it accurately reproduce a 50MHz square wave? A 1V RMS output is not going to reproduce a TTL 1PPS or 10MHz clock very well. It does state that each output is isolated and buffered. It reads as a general purpose wideband amplifier rather than one optimised for a particular timing application. Robert G8RPI From: Charles P. Steinmetz charles_steinm...@lavabit.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, 6 September 2012, 20:54 Subject: Re: [time-nuts] REF osc distribution. Luc wrote: We have a product that have been specially design for these : NGA-DIS Thank you for the link. The data sheet raises a few questions: The sine wave input level is specified as 1Vrms nominal 0.5V Peak to peak. Of course, 1Vrms is ~2.8Vp-p. It is not clear what this specification means. Gain and noise are not specified, nor is isolation from output to input or from the outputs to each other. These are parameters that many buyers will want to know. Have you characterized the NGA-DIS for phase noise? That is also a parameter many buyers will want to know. Does each output have its own output amplifier, or does one amplifier drive multiple outputs through individual build-out resistors? Does the NGA-DIS use op amps, or discrete circuitry? What is the price? Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] DCF77 Generation
Greetings, I have just written some code for generating DCF77 pulses given a 100ms clock interrupt and an accurate timestamp from a RTC, for a mate who has to get some imported clock movements synced up (we are in Australia which has no radio time service). I did a quick search and found very little out there from people generating their own DCF77 data, so I thought I'd ask if anyone else has ever done anything similar (and why as well). We are not transmitting, only faking the output from a DCF77 receiver. -- Dr. Celephicus ___ time-nuts mailing 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] DCF77 Generation
See wwvb1.c wwvb2.c wwvb3.c under my www.leapsecond.com/tools/ directory. There's some DCF77 support as I recall. Contact me offline if you have questions. /tvb - Original Message - From: Tom Harris celephi...@gmail.com To: time-nuts@febo.com Sent: Friday, September 07, 2012 5:53 AM Subject: [time-nuts] DCF77 Generation Greetings, I have just written some code for generating DCF77 pulses given a 100ms clock interrupt and an accurate timestamp from a RTC, for a mate who has to get some imported clock movements synced up (we are in Australia which has no radio time service). I did a quick search and found very little out there from people generating their own DCF77 data, so I thought I'd ask if anyone else has ever done anything similar (and why as well). We are not transmitting, only faking the output from a DCF77 receiver. -- Dr. Celephicus ___ time-nuts mailing 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] crystal (or MEMS) oscillators with low hysteresis
Consulting the hive-mind here on the list.. If one were looking for small/cheap/mass produced oscillators which have decent phase noise.. what kind has the most repeatable frequency vs temperature curve. The usual 1ppm TCXO has about 0.1 ppm hysteresis, while other less stable oscillators may have bigger variation with temperature (1ppm/degree C isn't a problem) but be more repeatable (perhaps the kind that they use as a thermometer?) And, then, are those available in an inexpensive mass produced form (e.g. the precision quartz thermometer is NOT inexpensive or mass produced) Phase noise need (not a hard requirement) is not a big driver -45 @ 1 Hz -75 @ 10 Hz -105 @ 100 Hz -130 @ 1 kHz -145 floor out to 15 MHz The parts I use now are actually about 10 dB better than that (-58 at 1 Hz, -90 @ 10 Hz, -117 at 100 Hz, and floor of -153) Ideally, I'd like to find something that has zero hysteresis.. BUT, if there is an equation that can predict the hysteresis by knowing the temperature history, that would probably work (although that has a bunch of problems... what about temperature changes when power is off) This isn't a spec that typically shows up in the mass produced XO catalog: they focus more on bounding the frequency error over some range of environments .. good to within 50 ppm from 10-55 C or something like that. So I'm looking for practical experience. ___ time-nuts mailing 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] Recommendations for a newbie?
Hello- My name is Robert Liesenfeld, I discovered this mailing list via the fascinating website leapsecond.com. I'm an amateur radio operator (AK6L) and builder, and my interest in precise timekeeping initially stemmed from simply wanting a very accurate clock source to which I could reference my test equipment (counter, spectrum analyzer, etc), but has expanded to a desire to perform timekeeping experiments. I have several questions; I looked for a FAQ but couldn't find one, so I hope it's alright to ask here. I'm considering the purchase of a GPS receiver to serve as my workbench 10MHz source. Since learning about precise timekeeping, I've also become interested in some experiments, such as measuring the stability of the mains, the effect of the ionosphere on WWV/WWVH signals, and so on. So far I've looked at various HP Z-boxes (Z3816, Z3815, Z3801, Z3805) and the Trimble Thunderbolt receiver. All of these seem to be in the $200-$500 range I'm targeting, but it's not clear what the differences are. I've read the Thunderbolt is an older design with fewer channels, but I don't know if that's really a problem for my intended use. I've also seen many rubidium devices on eBay, most seem to have been removed from CDMA cell tower service. Does anyone here have any experience with such devices, are the ex-cell-tower units any good? I have read that a rubidium standard's short-term stability is not as good as a GPSDO, and that they're mainly used for holdover - is my understanding correct? My thought is to (eventually) use a rubidium device to stabilize a GPSDO should the receiver lose satellite signal. Thank you in advance for any advice! -Robert ___ time-nuts mailing 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] DCF77 Generation
On Fri, 7 Sep 2012 22:53:50 +1000 Tom Harris celephi...@gmail.com wrote: I have just written some code for generating DCF77 pulses given a 100ms clock interrupt and an accurate timestamp from a RTC, for a mate who has to get some imported clock movements synced up (we are in Australia which has no radio time service). I did a quick search and found very little out there from people generating their own DCF77 data, so I thought I'd ask if anyone else has ever done anything similar (and why as well). We are not transmitting, only faking the output from a DCF77 receiver. Elrad (an old, discontinued german electronics magazine) had once an article on a DCF77 signal generator IIRC complete with 77.5kHz radio signal, somewhen in the second half of the 90s. If anyone is interested, i can try to track the article down in my archives. Attila Kinali -- There is no secret ingredient -- Po, Kung Fu Panda ___ time-nuts mailing 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] Recommendations for a newbie?
You want to start with a GPSDO. I like the Trimble Thunderbolt. The price is right and they're readily available. I have no experience with the HP units but they seem to be highly regarded. Rb oscillators are great for some things, but need to be calibrated. That's where the GPSDO comes in. Also, don't forget the antenna. You'll want something along these lines: http://www.ebay.com/itm/lucent-GPS-Timing-Reference-Antenna-antenne-40db-N-/230848464732?pt=GPS_Antennashash=item35bfa4075c#ht_2199wt_1404 Welcome aboard, and I'm apologizing in advance for how much money you'll be spending on new toys. -Bob On Fri, Sep 7, 2012 at 11:34 AM, Robert Liesenfeld xu...@xunil.net wrote: Hello- My name is Robert Liesenfeld, I discovered this mailing list via the fascinating website leapsecond.com. I'm an amateur radio operator (AK6L) and builder, and my interest in precise timekeeping initially stemmed from simply wanting a very accurate clock source to which I could reference my test equipment (counter, spectrum analyzer, etc), but has expanded to a desire to perform timekeeping experiments. I have several questions; I looked for a FAQ but couldn't find one, so I hope it's alright to ask here. I'm considering the purchase of a GPS receiver to serve as my workbench 10MHz source. Since learning about precise timekeeping, I've also become interested in some experiments, such as measuring the stability of the mains, the effect of the ionosphere on WWV/WWVH signals, and so on. So far I've looked at various HP Z-boxes (Z3816, Z3815, Z3801, Z3805) and the Trimble Thunderbolt receiver. All of these seem to be in the $200-$500 range I'm targeting, but it's not clear what the differences are. I've read the Thunderbolt is an older design with fewer channels, but I don't know if that's really a problem for my intended use. I've also seen many rubidium devices on eBay, most seem to have been removed from CDMA cell tower service. Does anyone here have any experience with such devices, are the ex-cell-tower units any good? I have read that a rubidium standard's short-term stability is not as good as a GPSDO, and that they're mainly used for holdover - is my understanding correct? My thought is to (eventually) use a rubidium device to stabilize a GPSDO should the receiver lose satellite signal. Thank you in advance for any advice! -Robert ___ time-nuts mailing 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] crystal (or MEMS) oscillators with low hysteresis
Hi I'm guessing that power is also an issue, so cheap OCXO's are out. If that's true, I believe you are already at the cheap vs good inflection point with the cell phone TCXO. At $2 they are pretty tough to beat. Just the fancy crystal in something better is going to give you a big boost in the price. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Jim Lux Sent: Friday, September 07, 2012 11:36 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] crystal (or MEMS) oscillators with low hysteresis Consulting the hive-mind here on the list.. If one were looking for small/cheap/mass produced oscillators which have decent phase noise.. what kind has the most repeatable frequency vs temperature curve. The usual 1ppm TCXO has about 0.1 ppm hysteresis, while other less stable oscillators may have bigger variation with temperature (1ppm/degree C isn't a problem) but be more repeatable (perhaps the kind that they use as a thermometer?) And, then, are those available in an inexpensive mass produced form (e.g. the precision quartz thermometer is NOT inexpensive or mass produced) Phase noise need (not a hard requirement) is not a big driver -45 @ 1 Hz -75 @ 10 Hz -105 @ 100 Hz -130 @ 1 kHz -145 floor out to 15 MHz The parts I use now are actually about 10 dB better than that (-58 at 1 Hz, -90 @ 10 Hz, -117 at 100 Hz, and floor of -153) Ideally, I'd like to find something that has zero hysteresis.. BUT, if there is an equation that can predict the hysteresis by knowing the temperature history, that would probably work (although that has a bunch of problems... what about temperature changes when power is off) This isn't a spec that typically shows up in the mass produced XO catalog: they focus more on bounding the frequency error over some range of environments .. good to within 50 ppm from 10-55 C or something like that. So I'm looking for practical experience. ___ time-nuts mailing 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] DCF77 Generation
Tom Just saw your post Though I have visited your site many times over the years never ran into these. Looking forward to downloading and trying the exes out tonight. I am working on the wwvb d-psk-r and this will be handy for the am in the modulator instead of fixed streams. Thanks On Fri, Sep 7, 2012 at 2:40 PM, Attila Kinali att...@kinali.ch wrote: On Fri, 7 Sep 2012 22:53:50 +1000 Tom Harris celephi...@gmail.com wrote: I have just written some code for generating DCF77 pulses given a 100ms clock interrupt and an accurate timestamp from a RTC, for a mate who has to get some imported clock movements synced up (we are in Australia which has no radio time service). I did a quick search and found very little out there from people generating their own DCF77 data, so I thought I'd ask if anyone else has ever done anything similar (and why as well). We are not transmitting, only faking the output from a DCF77 receiver. Elrad (an old, discontinued german electronics magazine) had once an article on a DCF77 signal generator IIRC complete with 77.5kHz radio signal, somewhen in the second half of the 90s. If anyone is interested, i can try to track the article down in my archives. Attila Kinali -- There is no secret ingredient -- Po, Kung Fu Panda ___ time-nuts mailing 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] Recommendations for a newbie?
Welcome aboard, yes, there is no FAQ about how to start in this hobby... should I try to implement one? Anyway, start with a Trimble Thunderbolt (aka TBolt), later you will know why it is highly recommended (direct OCXO disciplining and LH software support, mainly). I have a Z3815A with the famous (or infamous) E1938A hockey puck OCXO. They are all GPSDOs and there should not be any difference among them but, yes, there are differences in their performance and being a time-nut means test and find out. Then there are GPS disciplined Rubidiums, but take this step after the first GPSDO is correctly installed and stabilized. Start with the antenna: find a suitable place, with a 360 deg clear view of the sky, a satellite TV cable (sounds unusual, but works great). On Fri, Sep 7, 2012 at 8:52 PM, Robert Darlington rdarling...@gmail.comwrote: You want to start with a GPSDO. I like the Trimble Thunderbolt. The price is right and they're readily available. I have no experience with the HP units but they seem to be highly regarded. Rb oscillators are great for some things, but need to be calibrated. That's where the GPSDO comes in. Also, don't forget the antenna. You'll want something along these lines: http://www.ebay.com/itm/lucent-GPS-Timing-Reference-Antenna-antenne-40db-N-/230848464732?pt=GPS_Antennashash=item35bfa4075c#ht_2199wt_1404 Welcome aboard, and I'm apologizing in advance for how much money you'll be spending on new toys. -Bob On Fri, Sep 7, 2012 at 11:34 AM, Robert Liesenfeld xu...@xunil.net wrote: Hello- My name is Robert Liesenfeld, I discovered this mailing list via the fascinating website leapsecond.com. I'm an amateur radio operator (AK6L) and builder, and my interest in precise timekeeping initially stemmed from simply wanting a very accurate clock source to which I could reference my test equipment (counter, spectrum analyzer, etc), but has expanded to a desire to perform timekeeping experiments. I have several questions; I looked for a FAQ but couldn't find one, so I hope it's alright to ask here. I'm considering the purchase of a GPS receiver to serve as my workbench 10MHz source. Since learning about precise timekeeping, I've also become interested in some experiments, such as measuring the stability of the mains, the effect of the ionosphere on WWV/WWVH signals, and so on. So far I've looked at various HP Z-boxes (Z3816, Z3815, Z3801, Z3805) and the Trimble Thunderbolt receiver. All of these seem to be in the $200-$500 range I'm targeting, but it's not clear what the differences are. I've read the Thunderbolt is an older design with fewer channels, but I don't know if that's really a problem for my intended use. I've also seen many rubidium devices on eBay, most seem to have been removed from CDMA cell tower service. Does anyone here have any experience with such devices, are the ex-cell-tower units any good? I have read that a rubidium standard's short-term stability is not as good as a GPSDO, and that they're mainly used for holdover - is my understanding correct? My thought is to (eventually) use a rubidium device to stabilize a GPSDO should the receiver lose satellite signal. Thank you in advance for any advice! -Robert ___ time-nuts mailing 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] crystal (or MEMS) oscillators with low hysteresis
On 9/7/12 12:20 PM, Bob Camp wrote: Hi I'm guessing that power is also an issue, so cheap OCXO's are out. If that's true, I believe you are already at the cheap vs good inflection point with the cell phone TCXO. At $2 they are pretty tough to beat. Just the fancy crystal in something better is going to give you a big boost in the price. power and size.. Yes.. the cellphone tcxo is probably it.. but I was wondering if something else that's not TC might not have better hysteresis properties. Short of buying a batch and trying them... which I'll do, but before just randomly picking things out of the Digikey catalog, it's possible someone has more insight into the inner workings of cheap clock oscillators. For instance, they make inexpensive fairly high performance low power oscillators for COSPAS (emergency locator beacon) and wildlife tracker use. But you'd never know that they have the higher performance unless you asked. AT the high, expensive end, I've got all the data I need.. ___ time-nuts mailing 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] Recommendations for a newbie?
Hello Robert, your question is like asking which car you should buy, or which airline you should fly :) Everyone will have a different answer. But I do not recommend the Thunderbolts, it's a crab-shoot with them (different versions have different performance, the new ones are actually worse than older versions because of the temperature chip issue, the GPS is known to have lock issues, they don't work well until you spend a lot of time fine-tuning the parameters, etc etc) - that has all been discussed here ad-infinitum and you can find it in the archives. I recommend you search Ebay for HP 58503A. I just bought a number of them from a very well known seller in China, and they are absolutely superb, much better than any Rubidium unit I have tested. Much better than the Thunderbolt I have, and just slightly more expensive. He sells an entire kit for around $500, and it arrived here in less than a week (Northern California). This seller starts those units at around $260 I think. Performance you can get from these if you get a good one is: phase noise floor of around -163dBc, ADEV of 7E-013 to about 1E-012 to over 100s. Leapsecond.com has a number of test papers on these units. Caveat-emptor: there are significant unit-to-unit variations as with all GPSDO, Tom on leapsecond.com discusses this in detail. BTW: these are essentially the same unit as the Z3801A, just different software (ID string). I also have a Z3815A, and it is not even in the same class as the Z3801A/58503A. It is very noisy compared to the 58503A unit. I do not recommend the Z3815A, but it is a unique oscillator design,and some folks collect it for that oscillator. The 58503A uses a double oven version of the HP 10811A, which is a fantastic oscillator if you get a well-working one. If you want something low-cost with reasonable performance, brand new with warranty, antenna, and accessories, Jackson Labs Technologies, Inc. has the GPSTCXO eval kit for Time-Nuts special academic pricing of $300, which we believe is the lowest-cost true GPSDO (not NCO) in current production. Disclaimer: I work for them. bye, Said In a message dated 9/7/2012 13:09:24 Pacific Daylight Time, azelio.bori...@screen.it writes: Welcome aboard, yes, there is no FAQ about how to start in this hobby... should I try to implement one? Anyway, start with a Trimble Thunderbolt (aka TBolt), later you will know why it is highly recommended (direct OCXO disciplining and LH software support, mainly). I have a Z3815A with the famous (or infamous) E1938A hockey puck OCXO. They are all GPSDOs and there should not be any difference among them but, yes, there are differences in their performance and being a time-nut means test and find out. Then there are GPS disciplined Rubidiums, but take this step after the first GPSDO is correctly installed and stabilized. Start with the antenna: find a suitable place, with a 360 deg clear view of the sky, a satellite TV cable (sounds unusual, but works great). On Fri, Sep 7, 2012 at 8:52 PM, Robert Darlington rdarling...@gmail.comwrote: You want to start with a GPSDO. I like the Trimble Thunderbolt. The price is right and they're readily available. I have no experience with the HP units but they seem to be highly regarded. Rb oscillators are great for some things, but need to be calibrated. That's where the GPSDO comes in. Also, don't forget the antenna. You'll want something along these lines: http://www.ebay.com/itm/lucent-GPS-Timing-Reference-Antenna-antenne-40db-N-/230848464732?pt=GPS_Antennashash=item35bfa4075c#ht_2199wt_1404 Welcome aboard, and I'm apologizing in advance for how much money you'll be spending on new toys. -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] Recommendations for a newbie?
On Fri, Sep 7, 2012 at 10:34 AM, Robert Liesenfeld xu...@xunil.net wrote: Hello- I'm considering the purchase of a GPS receiver to serve as my workbench 10MHz source. Buy a Thunderbolt first. This is I think the best value and technicaly hard to beat. These is much support for the t-bolt here. many people know about them. ...I have read that a rubidium standard's short-term stability is not as good as a GPSDO, and that they're mainly used for holdover - is my understanding correct? My thought is to (eventually) use a rubidium device to stabilize a GPSDO should the receiver lose satellite signal. Hold over is their best use. But they work well as a portable standard and if you need something that can work quickly after power is applied with no need to set up a GPS antenna and wait for a self-survey. I is actually very unlikely that the GPS signal will fail. This might happen on a cell tower where some transmitter might fail and jam GPS but it is unlikely at your home. I think the Rb's best use is is portable or temporary uses where yo can't set up a GPS. One more thing. If your budget were lower you could build a GPSDO using a $20 GPS and a $20 OCXO plus some glue logic and get pretty good performance for about $100. The reason to build might be any of these (1) you want soething that uses very low power (2) you need some feature like automated failover to Rb on loss of signal, or (3) self education. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] crystal (or MEMS) oscillators with low hysteresis
Hi The crystals in the TCXO's are about as well mounted for hysteresis as you can practically do for the money. A typical clock oscillator guy does not worry much about that sort of mounting. Sorting is going to be a good idea. There are a number of things you likely will want to weed out. I'd plan on looking at a couple of different frequencies as well as vendors. Some quality time with a slow ramp / high data rate test setup should tell you a lot. 100 readings a degree and sub 1 degree per minute is the typical way to do it. Getting your temperature probe so it doesn't lag can be a hassle even at 1C/ minute Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Jim Lux Sent: Friday, September 07, 2012 4:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] crystal (or MEMS) oscillators with low hysteresis On 9/7/12 12:20 PM, Bob Camp wrote: Hi I'm guessing that power is also an issue, so cheap OCXO's are out. If that's true, I believe you are already at the cheap vs good inflection point with the cell phone TCXO. At $2 they are pretty tough to beat. Just the fancy crystal in something better is going to give you a big boost in the price. power and size.. Yes.. the cellphone tcxo is probably it.. but I was wondering if something else that's not TC might not have better hysteresis properties. Short of buying a batch and trying them... which I'll do, but before just randomly picking things out of the Digikey catalog, it's possible someone has more insight into the inner workings of cheap clock oscillators. For instance, they make inexpensive fairly high performance low power oscillators for COSPAS (emergency locator beacon) and wildlife tracker use. But you'd never know that they have the higher performance unless you asked. AT the high, expensive end, I've got all the data I need.. ___ time-nuts mailing 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] Recommendations for a newbie?
Robert, my bad, that seller offers 58503A units based on both Z3801A and Z3805A. The latter has a 16 channel GPS receiver, so seems to me much more desirable than the Z3801A. $50 difference. I have been testing the latter, not the former. bye, Said In a message dated 9/7/2012 13:37:52 Pacific Daylight Time, saidj...@aol.com writes: BTW: these are essentially the same unit as the Z3801A, just different software (ID string). ___ time-nuts mailing 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] Recommendations for a newbie?
Good one, the HP58503A, actually it is my reference at work. On Fri, Sep 7, 2012 at 10:37 PM, saidj...@aol.com wrote: Hello Robert, your question is like asking which car you should buy, or which airline you should fly :) Everyone will have a different answer. But I do not recommend the Thunderbolts, it's a crab-shoot with them (different versions have different performance, the new ones are actually worse than older versions because of the temperature chip issue, the GPS is known to have lock issues, they don't work well until you spend a lot of time fine-tuning the parameters, etc etc) - that has all been discussed here ad-infinitum and you can find it in the archives. I recommend you search Ebay for HP 58503A. I just bought a number of them from a very well known seller in China, and they are absolutely superb, much better than any Rubidium unit I have tested. Much better than the Thunderbolt I have, and just slightly more expensive. He sells an entire kit for around $500, and it arrived here in less than a week (Northern California). This seller starts those units at around $260 I think. Performance you can get from these if you get a good one is: phase noise floor of around -163dBc, ADEV of 7E-013 to about 1E-012 to over 100s. Leapsecond.com has a number of test papers on these units. Caveat-emptor: there are significant unit-to-unit variations as with all GPSDO, Tom on leapsecond.comdiscusses this in detail. BTW: these are essentially the same unit as the Z3801A, just different software (ID string). I also have a Z3815A, and it is not even in the same class as the Z3801A/58503A. It is very noisy compared to the 58503A unit. I do not recommend the Z3815A, but it is a unique oscillator design,and some folks collect it for that oscillator. The 58503A uses a double oven version of the HP 10811A, which is a fantastic oscillator if you get a well-working one. If you want something low-cost with reasonable performance, brand new with warranty, antenna, and accessories, Jackson Labs Technologies, Inc. has the GPSTCXO eval kit for Time-Nuts special academic pricing of $300, which we believe is the lowest-cost true GPSDO (not NCO) in current production. Disclaimer: I work for them. bye, Said In a message dated 9/7/2012 13:09:24 Pacific Daylight Time, azelio.bori...@screen.it writes: Welcome aboard, yes, there is no FAQ about how to start in this hobby... should I try to implement one? Anyway, start with a Trimble Thunderbolt (aka TBolt), later you will know why it is highly recommended (direct OCXO disciplining and LH software support, mainly). I have a Z3815A with the famous (or infamous) E1938A hockey puck OCXO. They are all GPSDOs and there should not be any difference among them but, yes, there are differences in their performance and being a time-nut means test and find out. Then there are GPS disciplined Rubidiums, but take this step after the first GPSDO is correctly installed and stabilized. Start with the antenna: find a suitable place, with a 360 deg clear view of the sky, a satellite TV cable (sounds unusual, but works great). On Fri, Sep 7, 2012 at 8:52 PM, Robert Darlington rdarling...@gmail.comwrote: You want to start with a GPSDO. I like the Trimble Thunderbolt. The price is right and they're readily available. I have no experience with the HP units but they seem to be highly regarded. Rb oscillators are great for some things, but need to be calibrated. That's where the GPSDO comes in. Also, don't forget the antenna. You'll want something along these lines: http://www.ebay.com/itm/lucent-GPS-Timing-Reference-Antenna-antenne-40db-N-/230848464732?pt=GPS_Antennashash=item35bfa4075c#ht_2199wt_1404 Welcome aboard, and I'm apologizing in advance for how much money you'll be spending on new toys. -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] Recommendations for a newbie?
Robert, you have gotten some good advice already. With regards to rubidium standards I've bought several of the cheaper rubidium units and with the benefit of hindsight I would have put the money towards a higher quality item such as a PRS 10. There are some good write ups on line that summarize the performance of the more commonly avaliable rubidium standards. If you haven't already done so you might want to start considering what type of measurement gear you are going to use for your experiments. Before purchasing a time interval counter I was able to do quite a bit of experimenting using a dual trace oscilloscope to compare two signals. Regards Mark Spencer ___ time-nuts mailing 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] Recommendations for a newbie?
Said, Where do you rank the Samsung GCRU-D among these? Jerry -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of saidj...@aol.com Sent: Friday, September 07, 2012 4:37 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Recommendations for a newbie? Hello Robert, your question is like asking which car you should buy, or which airline you should fly :) Everyone will have a different answer. But I do not recommend the Thunderbolts, it's a crab-shoot with them (different versions have different performance, the new ones are actually worse than older versions because of the temperature chip issue, the GPS is known to have lock issues, they don't work well until you spend a lot of time fine-tuning the parameters, etc etc) - that has all been discussed here ad-infinitum and you can find it in the archives. I recommend you search Ebay for HP 58503A. I just bought a number of them from a very well known seller in China, and they are absolutely superb, much better than any Rubidium unit I have tested. Much better than the Thunderbolt I have, and just slightly more expensive. He sells an entire kit for around $500, and it arrived here in less than a week (Northern California). This seller starts those units at around $260 I think. Performance you can get from these if you get a good one is: phase noise floor of around -163dBc, ADEV of 7E-013 to about 1E-012 to over 100s. Leapsecond.com has a number of test papers on these units. Caveat-emptor: there are significant unit-to-unit variations as with all GPSDO, Tom on leapsecond.com discusses this in detail. BTW: these are essentially the same unit as the Z3801A, just different software (ID string). I also have a Z3815A, and it is not even in the same class as the Z3801A/58503A. It is very noisy compared to the 58503A unit. I do not recommend the Z3815A, but it is a unique oscillator design,and some folks collect it for that oscillator. The 58503A uses a double oven version of the HP 10811A, which is a fantastic oscillator if you get a well-working one. If you want something low-cost with reasonable performance, brand new with warranty, antenna, and accessories, Jackson Labs Technologies, Inc. has the GPSTCXO eval kit for Time-Nuts special academic pricing of $300, which we believe is the lowest-cost true GPSDO (not NCO) in current production. Disclaimer: I work for them. bye, Said In a message dated 9/7/2012 13:09:24 Pacific Daylight Time, azelio.bori...@screen.it writes: Welcome aboard, yes, there is no FAQ about how to start in this hobby... should I try to implement one? Anyway, start with a Trimble Thunderbolt (aka TBolt), later you will know why it is highly recommended (direct OCXO disciplining and LH software support, mainly). I have a Z3815A with the famous (or infamous) E1938A hockey puck OCXO. They are all GPSDOs and there should not be any difference among them but, yes, there are differences in their performance and being a time-nut means test and find out. Then there are GPS disciplined Rubidiums, but take this step after the first GPSDO is correctly installed and stabilized. Start with the antenna: find a suitable place, with a 360 deg clear view of the sky, a satellite TV cable (sounds unusual, but works great). On Fri, Sep 7, 2012 at 8:52 PM, Robert Darlington rdarling...@gmail.comwrote: You want to start with a GPSDO. I like the Trimble Thunderbolt. The price is right and they're readily available. I have no experience with the HP units but they seem to be highly regarded. Rb oscillators are great for some things, but need to be calibrated. That's where the GPSDO comes in. Also, don't forget the antenna. You'll want something along these lines: http://www.ebay.com/itm/lucent-GPS-Timing-Reference-Antenna-antenne-40db-N-/ 230848464732?pt=GPS_Antennashash=item35bfa4075c#ht_2199wt_1404 Welcome aboard, and I'm apologizing in advance for how much money you'll be spending on new toys. -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] Recommendations for a newbie?
And this is the key: finding out what types of measurements can be done is part of the path to be taken being a time-nut. It is better to use what already may be available in the home lab (usually every experimenter has a 'scope) and delay the purchase of the test gear. On Sat, Sep 8, 2012 at 12:51 AM, Mark Spencer mspencer12...@yahoo.cawrote: Robert, you have gotten some good advice already. With regards to rubidium standards I've bought several of the cheaper rubidium units and with the benefit of hindsight I would have put the money towards a higher quality item such as a PRS 10. There are some good write ups on line that summarize the performance of the more commonly avaliable rubidium standards. If you haven't already done so you might want to start considering what type of measurement gear you are going to use for your experiments. Before purchasing a time interval counter I was able to do quite a bit of experimenting using a dual trace oscilloscope to compare two signals. Regards Mark Spencer ___ time-nuts mailing 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] Recommendations for a newbie?
Dear Said, Good afternoon. How is the service and cosmetic condition of the HP GPS products you have bought from this source? I am considering a Z3805A just for the sake of owning one and the versatility of plug and play. Still afraid to take the plunge. Did you buy a raw unit? Or as a kit with antenna. Is that a 5V or 12V antenna? I am integrating a TBolt into a 1U rack case which also has space for a Rb oscillator for future disciplining. Got a nice TBolt monitor and would love to also include a frequency divider to get 5 and 1MHz from the TBolt. Your kind comments are welcome. Thank you. Regards, Edgardo Molina Dirección IPTEL www.iptel.net.mx T : 55 55 55202444 M : 04455 20501854 Piensa en Bits SA de CV Información anexa: CONFIDENCIALIDAD DE INFORMACION Este mensaje tiene carácter confidencial. Si usted no es el destinarario de este mensaje, le suplicamos se lo notifique al remitente mediante un correo electrónico y que borre el presente mensaje y sus anexos de su computadora sin retener una copia de los mismos. Queda estrictamente prohibido copiar este mensaje o hacer usode el para cualquier propósito o divulgar su en forma parcial o total su contenido. Gracias. NON-DISCLOSURE OF INFORMATION This email is strictly confidential and may also be privileged. If you are not the intended recipient please immediately advise the sender by replying to this e-mail and then deleting the message and its attachments from your computer without keeping a copy. It is strictly forbidden to copy it or use it for any purpose or disclose its contents to any third party. Thank you. On Sep 7, 2012, at 3:56 PM, saidj...@aol.com wrote: Robert, my bad, that seller offers 58503A units based on both Z3801A and Z3805A. The latter has a 16 channel GPS receiver, so seems to me much more desirable than the Z3801A. $50 difference. I have been testing the latter, not the former. bye, Said In a message dated 9/7/2012 13:37:52 Pacific Daylight Time, saidj...@aol.com writes: BTW: these are essentially the same unit as the Z3801A, just different software (ID string). ___ time-nuts mailing 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] Recommendations for a newbie?
Dear Azelio, Do you know how the Z3805A compares to the 58503A? Cheers! Edgardo Molina Dirección IPTEL www.iptel.net.mx T : 55 55 55202444 M : 04455 20501854 Piensa en Bits SA de CV Información anexa: CONFIDENCIALIDAD DE INFORMACION Este mensaje tiene carácter confidencial. Si usted no es el destinarario de este mensaje, le suplicamos se lo notifique al remitente mediante un correo electrónico y que borre el presente mensaje y sus anexos de su computadora sin retener una copia de los mismos. Queda estrictamente prohibido copiar este mensaje o hacer usode el para cualquier propósito o divulgar su en forma parcial o total su contenido. Gracias. NON-DISCLOSURE OF INFORMATION This email is strictly confidential and may also be privileged. If you are not the intended recipient please immediately advise the sender by replying to this e-mail and then deleting the message and its attachments from your computer without keeping a copy. It is strictly forbidden to copy it or use it for any purpose or disclose its contents to any third party. Thank you. On Sep 7, 2012, at 3:58 PM, Azelio Boriani azelio.bori...@screen.it wrote: Good one, the HP58503A, actually it is my reference at work. On Fri, Sep 7, 2012 at 10:37 PM, saidj...@aol.com wrote: Hello Robert, your question is like asking which car you should buy, or which airline you should fly :) Everyone will have a different answer. But I do not recommend the Thunderbolts, it's a crab-shoot with them (different versions have different performance, the new ones are actually worse than older versions because of the temperature chip issue, the GPS is known to have lock issues, they don't work well until you spend a lot of time fine-tuning the parameters, etc etc) - that has all been discussed here ad-infinitum and you can find it in the archives. I recommend you search Ebay for HP 58503A. I just bought a number of them from a very well known seller in China, and they are absolutely superb, much better than any Rubidium unit I have tested. Much better than the Thunderbolt I have, and just slightly more expensive. He sells an entire kit for around $500, and it arrived here in less than a week (Northern California). This seller starts those units at around $260 I think. Performance you can get from these if you get a good one is: phase noise floor of around -163dBc, ADEV of 7E-013 to about 1E-012 to over 100s. Leapsecond.com has a number of test papers on these units. Caveat-emptor: there are significant unit-to-unit variations as with all GPSDO, Tom on leapsecond.comdiscusses this in detail. BTW: these are essentially the same unit as the Z3801A, just different software (ID string). I also have a Z3815A, and it is not even in the same class as the Z3801A/58503A. It is very noisy compared to the 58503A unit. I do not recommend the Z3815A, but it is a unique oscillator design,and some folks collect it for that oscillator. The 58503A uses a double oven version of the HP 10811A, which is a fantastic oscillator if you get a well-working one. If you want something low-cost with reasonable performance, brand new with warranty, antenna, and accessories, Jackson Labs Technologies, Inc. has the GPSTCXO eval kit for Time-Nuts special academic pricing of $300, which we believe is the lowest-cost true GPSDO (not NCO) in current production. Disclaimer: I work for them. bye, Said In a message dated 9/7/2012 13:09:24 Pacific Daylight Time, azelio.bori...@screen.it writes: Welcome aboard, yes, there is no FAQ about how to start in this hobby... should I try to implement one? Anyway, start with a Trimble Thunderbolt (aka TBolt), later you will know why it is highly recommended (direct OCXO disciplining and LH software support, mainly). I have a Z3815A with the famous (or infamous) E1938A hockey puck OCXO. They are all GPSDOs and there should not be any difference among them but, yes, there are differences in their performance and being a time-nut means test and find out. Then there are GPS disciplined Rubidiums, but take this step after the first GPSDO is correctly installed and stabilized. Start with the antenna: find a suitable place, with a 360 deg clear view of the sky, a satellite TV cable (sounds unusual, but works great). On Fri, Sep 7, 2012 at 8:52 PM, Robert Darlington rdarling...@gmail.comwrote: You want to start with a GPSDO. I like the Trimble Thunderbolt. The price is right and they're readily available. I have no experience with the HP units but they seem to be highly regarded. Rb oscillators are great for some things, but need to be calibrated. That's where the GPSDO comes in. Also, don't forget the antenna. You'll want something along these lines: http://www.ebay.com/itm/lucent-GPS-Timing-Reference-Antenna-antenne-40db-N-/230848464732?pt=GPS_Antennashash=item35bfa4075c#ht_2199wt_1404 Welcome
Re: [time-nuts] Recommendations for a newbie?
Hi Edgardo, they work well for me, look brand-new, and came with power supply, rs-232 cable, and antenna. I think it's a 5V antenna. The unit had about 37000 on the lifetime. The seller has close up photos, that's what the units look like. I plugged in the power, ran GPSCon to start an Auto-Survey, and they just worked. I now get less than 3us predicted drift over 24 hours from one of the units, which is quite good according to others. I think these are pretty good for the money (free shipping on mine) but there are differences between the three units I have just like the Z3801A plots on leapsecond.com. Hope that helps, Said In a message dated 9/7/2012 17:13:22 Pacific Daylight Time, xe1...@amsat.org writes: Dear Said, Good afternoon. How is the service and cosmetic condition of the HP GPS products you have bought from this source? I am considering a Z3805A just for the sake of owning one and the versatility of plug and play. Still afraid to take the plunge. Did you buy a raw unit? Or as a kit with antenna. Is that a 5V or 12V antenna? I am integrating a TBolt into a 1U rack case which also has space for a Rb oscillator for future disciplining. Got a nice TBolt monitor and would love to also include a frequency divider to get 5 and 1MHz from the TBolt. Your kind comments are welcome. Thank you. Regards, Edgardo Molina Dirección IPTEL ___ time-nuts mailing 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] Recommendations for a newbie?
Hi Jerry, I am not familiar with those, sorry. The only complaint I would have about the 58503A units I have is that they have a bit of power supply spurs at about -130dBc. Running them from batteries would probably take care of that. Otherwise they work great for me and provide both great ADEV and very good phase noise at the same time, what else can one ask for $550.. But again, there may be large unit-to-unit variations as Tom has found out, and I may have been lucky with the units I received.. bye, Said In a message dated 9/7/2012 15:55:04 Pacific Daylight Time, jster...@att.net writes: Said, Where do you rank the Samsung GCRU-D among these? Jerry ___ time-nuts mailing 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] Recommendations for a newbie?
Dear Said, Thank you for your kind explanation. I will be considering such a purchase in the near future. I will keep you informed about my experiences. You have a nice evening. Regards, Edgardo Molina Dirección IPTEL www.iptel.net.mx T : 55 55 55202444 M : 04455 20501854 Piensa en Bits SA de CV Información anexa: CONFIDENCIALIDAD DE INFORMACION Este mensaje tiene carácter confidencial. Si usted no es el destinarario de este mensaje, le suplicamos se lo notifique al remitente mediante un correo electrónico y que borre el presente mensaje y sus anexos de su computadora sin retener una copia de los mismos. Queda estrictamente prohibido copiar este mensaje o hacer usode el para cualquier propósito o divulgar su en forma parcial o total su contenido. Gracias. NON-DISCLOSURE OF INFORMATION This email is strictly confidential and may also be privileged. If you are not the intended recipient please immediately advise the sender by replying to this e-mail and then deleting the message and its attachments from your computer without keeping a copy. It is strictly forbidden to copy it or use it for any purpose or disclose its contents to any third party. Thank you. On Sep 7, 2012, at 8:14 PM, saidj...@aol.com wrote: Hi Edgardo, they work well for me, look brand-new, and came with power supply, rs-232 cable, and antenna. I think it's a 5V antenna. The unit had about 37000 on the lifetime. The seller has close up photos, that's what the units look like. I plugged in the power, ran GPSCon to start an Auto-Survey, and they just worked. I now get less than 3us predicted drift over 24 hours from one of the units, which is quite good according to others. I think these are pretty good for the money (free shipping on mine) but there are differences between the three units I have just like the Z3801A plots on leapsecond.com. Hope that helps, Said In a message dated 9/7/2012 17:13:22 Pacific Daylight Time, xe1...@amsat.org writes: Dear Said, Good afternoon. How is the service and cosmetic condition of the HP GPS products you have bought from this source? I am considering a Z3805A just for the sake of owning one and the versatility of plug and play. Still afraid to take the plunge. Did you buy a raw unit? Or as a kit with antenna. Is that a 5V or 12V antenna? I am integrating a TBolt into a 1U rack case which also has space for a Rb oscillator for future disciplining. Got a nice TBolt monitor and would love to also include a frequency divider to get 5 and 1MHz from the TBolt. Your kind comments are welcome. Thank you. Regards, Edgardo Molina Dirección IPTEL ___ time-nuts mailing 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.
