Re: [time-nuts] Ebay FE-5680A Rb: Are they that good?
El 09/12/2011 02:27, Peter Bell escribió: 5) Although the output is a sine wave, it's not especially nice - internally it's derived from a square wave fed into a rather simple filter circuit - having said that, none of my test gear has any problem with using it for a reference input, Regards. Pete Hello! Well, at least it is not so ugly as one would have expected :) I've compiled some oscillograms and spectra from it here: http://www.nebulosa.org/images/FE5680A/ The analog one is with a Tek11302 and 11A71 (500MHz BW). Regards, Javier, EA1CRB ___ time-nuts mailing 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] UK GPS jamming - February 2012
UK GPS jamming - February 2012 I have received the following: ___ NOTIFICATION OF GPS JAMMING EXERCISES RAF SCULTHORPE AIRFIELD, EAST ANGLIA, FEBRUARY 2012 Dates: Between 6 and 10 February 2012 inclusive. Times: between 0700 and 1700 GMT. Location of SINGLE jammer: Land based within 2km of 52° 50' 54? N, 0° 45' 38? E. Frequency: A 20 MHz band centred around 1575.42MHz (GPS L1). Total Power: Up to 0.1 Watts EIRP (100mW). It is stressed that, as in previous exercises, Safety of Life operations will at all times take precedence over exercise activities. ___ Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ebay FE-5680A Rb: Are they that good?
Javier, the plots are nice, and I did the same years ago for an Efratom FRS-C. Found about the same data. The only point is that with the spectrum analyzer you see the S/A pahse noise, not the Rb, wich has to be orders of magnitude lower. About the comments on the waveform and harmonics contents: who cares about having the 2nd harmonic at -30 or -50 dB? For any practical use one has to square the signal, and the original harmonic content is of no pratical interest, or I am missing something ... 73 - Marco IK1ODO / AI4YF ___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
Marco Think you are correct for most things we do. However in communications for mixing and such a sine wave is desirable and a very clean output to minimize things like IMD and other products as we get the 10 MC to its final frequency. Since you are a ham you may appreciate that. Regards Paul WB8TSL On Fri, Dec 9, 2011 at 8:10 AM, Marco IK1ODO -2 ik1...@spin-it.com wrote: Javier, the plots are nice, and I did the same years ago for an Efratom FRS-C. Found about the same data. The only point is that with the spectrum analyzer you see the S/A pahse noise, not the Rb, wich has to be orders of magnitude lower. About the comments on the waveform and harmonics contents: who cares about having the 2nd harmonic at -30 or -50 dB? For any practical use one has to square the signal, and the original harmonic content is of no pratical interest, or I am missing something ... 73 - Marco IK1ODO / AI4YF __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Oscilloquartz 5240 GPSDO
Hi All, If anyone is ever in need of Local Management Software for the OSA 5240, drop me a private mail. Great unit at Zero cost. After config the 3RU case is equipped with 16 x BNC outputs at 10MHz 1VRMS into 50 Ohm. Regards Gerald VK3GJM ___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
Hello, Yes, I know that the phase noise is the spectrum analyzer one, but the spurious that are around (mostly -70, -80dBc) are not, particularly the ones at +/200kHz and +/-400kHz. I was mostly curious about the harmonics and other spurii since in this unit, 10MHz are generated from a CPLD divider, and this approach sometimes leds to strange spurious and nasty things around, but in this case seems not bad. As far as I remember, in a FRS-C the output is from a 10MHz crystal oscillator. And the harmonics, well... usually we square that output and they have not importance, but sometimes it is desirable to have a clean as possible signal, and I was curious to see how good (or bad) the filtering was :). On other side, we can use square wave from the CPLD (not yet checked, but it must be there inside, somewhere :) ). The 2nd harmonic is very low, that indicates that square wave symmetry is very good. Regards, Javier, EA1CRB El 09/12/2011 14:10, Marco IK1ODO -2 escribió: Javier, the plots are nice, and I did the same years ago for an Efratom FRS-C. Found about the same data. The only point is that with the spectrum analyzer you see the S/A pahse noise, not the Rb, wich has to be orders of magnitude lower. About the comments on the waveform and harmonics contents: who cares about having the 2nd harmonic at -30 or -50 dB? For any practical use one has to square the signal, and the original harmonic content is of no pratical interest, or I am missing something ... 73 - Marco IK1ODO / AI4YF ___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
Getting the square wave out is easy - if you follow down the trace from that J8 socket (which is also connected to the output on the D-type) it goes to a cap - just remove that and solder a jumper across the pair of pads to the left of it (I.E. closer to the PLD). Regards, Pete On Fri, Dec 9, 2011 at 9:32 PM, Javier Herrero jherr...@hvsistemas.es wrote: Hello, Yes, I know that the phase noise is the spectrum analyzer one, but the spurious that are around (mostly -70, -80dBc) are not, particularly the ones at +/200kHz and +/-400kHz. I was mostly curious about the harmonics and other spurii since in this unit, 10MHz are generated from a CPLD divider, and this approach sometimes leds to strange spurious and nasty things around, but in this case seems not bad. As far as I remember, in a FRS-C the output is from a 10MHz crystal oscillator. And the harmonics, well... usually we square that output and they have not importance, but sometimes it is desirable to have a clean as possible signal, and I was curious to see how good (or bad) the filtering was :). On other side, we can use square wave from the CPLD (not yet checked, but it must be there inside, somewhere :) ). The 2nd harmonic is very low, that indicates that square wave symmetry is very good. Regards, Javier, EA1CRB El 09/12/2011 14:10, Marco IK1ODO -2 escribió: Javier, the plots are nice, and I did the same years ago for an Efratom FRS-C. Found about the same data. The only point is that with the spectrum analyzer you see the S/A pahse noise, not the Rb, wich has to be orders of magnitude lower. About the comments on the waveform and harmonics contents: who cares about having the 2nd harmonic at -30 or -50 dB? For any practical use one has to square the signal, and the original harmonic content is of no pratical interest, or I am missing something ... 73 - Marco IK1ODO / AI4YF ___ time-nuts mailing 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. attachment: RF_Conn_sml.jpg___ time-nuts mailing 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] Anyone know anything about the Oscilloquartz GPSCU II-B ?
Seeing that other post about an Oscilloquartz GPSDO made me wonder if anyone on here knows about these? It's a board-level product, which looks very much lile it's designed to go into some piece of telecoms equipment. Push button switch, 2 SMA connectors and a D-type on the front panel - carrier board on standoffs in the middle of the main PCB (with a barcode label marked gcm) with 3-sub boards on it - one is a Navicom GPS receiver module, one is a carrier board with a 8663-XS OCXO on it and the third is marked MPU Ver 2.0 NAVICOM PTS Team and has a barcode label marked proc. Sounds familiar to anyone? Regards, Pete ___ time-nuts mailing 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] Anyone know anything about the Oscilloquartz GPSCU II-B ?
Can you let us have a picture? Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Bell Sent: 09 December 2011 13:55 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Anyone know anything about the Oscilloquartz GPSCU II-B ? Seeing that other post about an Oscilloquartz GPSDO made me wonder if anyone on here knows about these? It's a board-level product, which looks very much lile it's designed to go into some piece of telecoms equipment. Push button switch, 2 SMA connectors and a D-type on the front panel - carrier board on standoffs in the middle of the main PCB (with a barcode label marked gcm) with 3-sub boards on it - one is a Navicom GPS receiver module, one is a carrier board with a 8663-XS OCXO on it and the third is marked MPU Ver 2.0 NAVICOM PTS Team and has a barcode label marked proc. Sounds familiar to anyone? Regards, Pete ___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
At 14:21 09-12-11, you wrote: Marco Think you are correct for most things we do. However in communications for mixing and such a sine wave is desirable and a very clean output to minimize things like IMD and other products as we get the 10 MC to its final frequency. Since you are a ham you may appreciate that. Regards Paul WB8TSL Hello Paul, I understand, but don't agree 100% :-) - I mean, doing radio either you use the 10 MHz for syncing oscillators in you chain (I do that for EME, all is derived from a FRK-HLN), or you use the 10 MHz directly to a mixer. The mixer usually is inherently non linear; if you look at the current in the diodes of a ring mixer, it is almost squared. More it is squared, more abrupt is the diode switching, better the mixer dynamic range. And many mixers are sensitive to harmonics (see Tayloe mixer) of the input signal or use harmonic mixing schemes (see any S/A), only possible if the mixer current is highly non-sinusoidal. So, I agree with Javier about the search for existence of low lever spurious signals, but don't understand the need to have a (very) low harmonic content. Oh, well, to have too many harmonics is a bad thing - one time I had radiation problems from a coax feeding a 10 MHz squared signal, with components over 100 MHz - but this is an extreme case. 73 - Marco IK1ODO / AI4YF ___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
Marco I understand also. But good enough for this conversation. What I find interesting is that you can not even find a good xtal these days for $40. Yet here is a complete package that delivers quite a bang for the buck. I have wavered back and forth on buying one since I already have numbers of these types of references. So far I have pulled back. Another one? Regards On Fri, Dec 9, 2011 at 9:54 AM, Marco IK1ODO -2 ik1...@spin-it.com wrote: At 14:21 09-12-11, you wrote: Marco Think you are correct for most things we do. However in communications for mixing and such a sine wave is desirable and a very clean output to minimize things like IMD and other products as we get the 10 MC to its final frequency. Since you are a ham you may appreciate that. Regards Paul WB8TSL Hello Paul, I understand, but don't agree 100% :-) - I mean, doing radio either you use the 10 MHz for syncing oscillators in you chain (I do that for EME, all is derived from a FRK-HLN), or you use the 10 MHz directly to a mixer. The mixer usually is inherently non linear; if you look at the current in the diodes of a ring mixer, it is almost squared. More it is squared, more abrupt is the diode switching, better the mixer dynamic range. And many mixers are sensitive to harmonics (see Tayloe mixer) of the input signal or use harmonic mixing schemes (see any S/A), only possible if the mixer current is highly non-sinusoidal. So, I agree with Javier about the search for existence of low lever spurious signals, but don't understand the need to have a (very) low harmonic content. Oh, well, to have too many harmonics is a bad thing - one time I had radiation problems from a coax feeding a 10 MHz squared signal, with components over 100 MHz - but this is an extreme case. 73 - Marco IK1ODO / AI4YF __**_ 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] Ebay FE-5680A Rb: Are they that good?
Paul I was exactly where you are. The last thing I needed was an other Rb. But an Rb at $ 40 I did bite the bullet and running the tests I do not regret it. Bert Kehren In a message dated 12/9/2011 10:11:06 A.M. Eastern Standard Time, paulsw...@gmail.com writes: Marco I understand also. But good enough for this conversation. What I find interesting is that you can not even find a good xtal these days for $40. Yet here is a complete package that delivers quite a bang for the buck. I have wavered back and forth on buying one since I already have numbers of these types of references. So far I have pulled back. Another one? Regards On Fri, Dec 9, 2011 at 9:54 AM, Marco IK1ODO -2 ik1...@spin-it.com wrote: At 14:21 09-12-11, you wrote: Marco Think you are correct for most things we do. However in communications for mixing and such a sine wave is desirable and a very clean output to minimize things like IMD and other products as we get the 10 MC to its final frequency. Since you are a ham you may appreciate that. Regards Paul WB8TSL Hello Paul, I understand, but don't agree 100% :-) - I mean, doing radio either you use the 10 MHz for syncing oscillators in you chain (I do that for EME, all is derived from a FRK-HLN), or you use the 10 MHz directly to a mixer. The mixer usually is inherently non linear; if you look at the current in the diodes of a ring mixer, it is almost squared. More it is squared, more abrupt is the diode switching, better the mixer dynamic range. And many mixers are sensitive to harmonics (see Tayloe mixer) of the input signal or use harmonic mixing schemes (see any S/A), only possible if the mixer current is highly non-sinusoidal. So, I agree with Javier about the search for existence of low lever spurious signals, but don't understand the need to have a (very) low harmonic content. Oh, well, to have too many harmonics is a bad thing - one time I had radiation problems from a coax feeding a 10 MHz squared signal, with components over 100 MHz - but this is an extreme case. 73 - Marco IK1ODO / AI4YF __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
I understand Bert. But you wanted to test it. I actually don't have a real reason grab one of these jewels. Though understanding when the piles gone, its gone. Thats the way it works on this stuff. But I have 6 of the old cel site Lucent RBs all $20 and a Good HP 5065 and then last spring a lpro 101 for $20. Granted the Lucents are fairly old in years with OK lamp voltage still. Just concerned about becoming a RB addict and having to join a multi-step with-drawl program. God knows I may still buy two. Shipping included. :-) Regards Paul On Fri, Dec 9, 2011 at 10:19 AM, ewkeh...@aol.com wrote: Paul I was exactly where you are. The last thing I needed was an other Rb. But an Rb at $ 40 I did bite the bullet and running the tests I do not regret it. Bert Kehren In a message dated 12/9/2011 10:11:06 A.M. Eastern Standard Time, paulsw...@gmail.com writes: Marco I understand also. But good enough for this conversation. What I find interesting is that you can not even find a good xtal these days for $40. Yet here is a complete package that delivers quite a bang for the buck. I have wavered back and forth on buying one since I already have numbers of these types of references. So far I have pulled back. Another one? Regards On Fri, Dec 9, 2011 at 9:54 AM, Marco IK1ODO -2 ik1...@spin-it.com wrote: At 14:21 09-12-11, you wrote: Marco Think you are correct for most things we do. However in communications for mixing and such a sine wave is desirable and a very clean output to minimize things like IMD and other products as we get the 10 MC to its final frequency. Since you are a ham you may appreciate that. Regards Paul WB8TSL Hello Paul, I understand, but don't agree 100% :-) - I mean, doing radio either you use the 10 MHz for syncing oscillators in you chain (I do that for EME, all is derived from a FRK-HLN), or you use the 10 MHz directly to a mixer. The mixer usually is inherently non linear; if you look at the current in the diodes of a ring mixer, it is almost squared. More it is squared, more abrupt is the diode switching, better the mixer dynamic range. And many mixers are sensitive to harmonics (see Tayloe mixer) of the input signal or use harmonic mixing schemes (see any S/A), only possible if the mixer current is highly non-sinusoidal. So, I agree with Javier about the search for existence of low lever spurious signals, but don't understand the need to have a (very) low harmonic content. Oh, well, to have too many harmonics is a bad thing - one time I had radiation problems from a coax feeding a 10 MHz squared signal, with components over 100 MHz - but this is an extreme case. 73 - Marco IK1ODO / AI4YF __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nuts https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ebay FE-5680A Rb: Are they that good?
I've ordered one. Meanwhile, my Racal-Dana 1992 soldiers on nicely. The attached is a gnuplot of a few days' measurements of the Trimble Thunderbolt's 10 MHz output. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 attachment: 1992.gif___ time-nuts mailing 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] Anyone know anything about the Oscilloquartz GPSCU II-B ?
I guess I need somewhere to upload it, since the file size restriction on the list makes it impossible to get any detail... This should give you a vague idea, anyway. Regards, Pete On Fri, Dec 9, 2011 at 10:47 PM, Robin Kimberley robkimber...@btinternet.com wrote: Can you let us have a picture? Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Bell Sent: 09 December 2011 13:55 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Anyone know anything about the Oscilloquartz GPSCU II-B ? Seeing that other post about an Oscilloquartz GPSDO made me wonder if anyone on here knows about these? It's a board-level product, which looks very much lile it's designed to go into some piece of telecoms equipment. Push button switch, 2 SMA connectors and a D-type on the front panel - carrier board on standoffs in the middle of the main PCB (with a barcode label marked gcm) with 3-sub boards on it - one is a Navicom GPS receiver module, one is a carrier board with a 8663-XS OCXO on it and the third is marked MPU Ver 2.0 NAVICOM PTS Team and has a barcode label marked proc. Sounds familiar to anyone? Regards, Pete ___ time-nuts mailing 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. attachment: GPSCU II-B_sml.jpg___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
At 18:23 09-12-11, Javier wrote: I think that the low-band preselector (I don't remember the model) was more oriented to increase the dynamic range for EMC testing, rather than due to a crappy harmonic response of the analyzer. It also includes a preamplifier. Correct. 85685A, a very expensive (then and now) piece. The problem there was to limit the impulse bandwidth of the frontend, harmonic response was not a concern. In general, if you want to reliably measure harmonics with a S/A, you have to cancel the fundamental, either with a notch or low pass filter. 73 - Marco IK1ODO ___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
El 09/12/2011 18:54, Marco IK1ODO -2 escribió: At 18:23 09-12-11, Javier wrote: I think that the low-band preselector (I don't remember the model) was more oriented to increase the dynamic range for EMC testing, rather than due to a crappy harmonic response of the analyzer. It also includes a preamplifier. Correct. 85685A, a very expensive (then and now) piece. The problem there was to limit the impulse bandwidth of the frontend, harmonic response was not a concern. In general, if you want to reliably measure harmonics with a S/A, you have to cancel the fundamental, either with a notch or low pass filter. Right (except I suppose that high pass, no low pass :) ) Regards, Javier ___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
Bob Smither wrote: Chuck Forsberg WA7KGX N2469R wrote: The price seems reasonable, esp. with free shipping. Does anyone have experience with these? Is the circuit board included? I could not resist at $40.00 delivered. Mine has been running for a couple of weeks, but my measurements have been inconclusive (I suspect my setup is far from ideal, especially the handling of the 10 MHz signal). I rebuilt my FE-5680A setup with new power supplies and better routing of the 10MHz output. BTW - I noticed that mine has a 1PPS output (~1usec positive +5V pulse) on pin 6 of the DB9 connector. The results are much more consistent with the new setup. I have a 1PPS that is derived from the FE-5680A (not the native 1PPS output on pin 6) that is compared to the 1 PPS from a GPS receiver. The first 15 hours of data can be seen here: http://c-c-i.com/node/154 From the data, it looks like my FE-5680A is running about 1.7E-10 fast. The data sheet specifies aging of 2E-9/year so this seems reasonable. I have been able to talk to it through the RS-232 port (pin 9 is output from FE-5680A, pin 8 is input to FE-5680A). Using Cutecom on Linux with 9600 8N1 results in the following dialog: 2d 04 00 29 - input command - request frequency offset 2d 09 00 24 00 00 00 00 00 - reply From the reply I am assuming that my unit has no programmed offset (32 bits of zeros - last hex digit is the data checksum). My documentation states that the full range of adjustment is: 7f ff ff ff = +383 Hz 80 00 00 00 = -383 Hz To correct the 1.7E-10 offset I need to slow it down by .0017 Hz or a count of -9532. After this unit runs for 24 hours I will try to program in the correction. More later ... -- Bob Smither, PhD Circuit Concepts, Inc. = The American Republic will endure, until politicians realize they can bribe the people with their own money. -- Alexis de Tocqueville = smit...@c-c-i.com http://www.C-C-I.Com 281-331-2744(office) -4616(fax) attachment: smither.vcf___ time-nuts mailing 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] Time in the 10,000-Year Clock
I noticed that the topic of the Long Now 10,000-year clock came up here last month. A paper on its timekeeping issues will be published in the proceedings of Decoupling Civil Timekeeping from Earth Rotation, a meeting held in Pennsylvania in October: http://futureofutc.org The preprint is available at: http://www.cacr.caltech.edu/futureofutc/preprints/10_AAS_11-665_Hillis.pdf Slides, transcribed discussions, and other papers may also be of interest to list members. Rob Seaman National Optical Astronomy Observatory ___ time-nuts mailing 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] Ebay FE-5680A Rb: Are they that good?
Bob Smither wrote: snip My documentation states that the full range of adjustment is: 7f ff ff ff = +383 Hz 80 00 00 00 = -383 Hz This scale factor is clearly wrong - using it and applying an appropriate correction changes the frequency way too much. From: http://article.gmane.org/gmane.comp.time.nuts/9473/match=fe+5680+pin+outs (thanks Jose!) a better estimate is 14 / Hz. Using data after 20 hours: http://www.c-c-i.com/node/155 the estimated frequency offset is 1.36E-3 Hz. Using the above scale factor gives a correction of -190 counts. Here is the command I used to (temporarily) program the new offset: 2e 09 00 27 ff ff ff 42 bd (the bd is the exclusive-or checksum of the offset) Now I wait ... -- Bob Smither, PhD Circuit Concepts, Inc. = A government which robs Peter to pay Paul can always depend on the support of Paul. --George Bernard Shaw = smit...@c-c-i.com http://www.C-C-I.Com 281-331-2744(office) -4616(fax) attachment: smither.vcf___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
