Re: [time-nuts] Speedy neutrino puzzle solved
I don't know what the experimental setup is. However if I were to be using GPS, I would use the GPS system to get a precise time at each end, record the time of the event that should generate the neutrino burst at one end precisely to a clock set by GPS and record the arrival time at the other end. The observation from the GPS frame is irrelevant if that way the experiment is performed. I would think the mathematics of GPS timing and calculations would already have the relativistic effects factored into constants. I vaguely recall such things in there, but the whole GPS system is something hard to retain and recall at this point to find references about that. I read some amount about the calculations in reading a patent some years ago which was to try to use a couple of PC's to do the calculations among other things, and had an analysis of the time required to do the calculations. I need to find it because there were estimates of how long each part of the system calculations took to justify that the scheme would work. I assumed that if one were solving a multi term equation of readings to arrive at a spatial value from the timing information that the motion of the satellites would have to have had the relativistic effects factored in. So it would not be present in my above description of the experiment. Jim On 10/15/2011 8:13 PM, Bob Smither wrote: Mike S wrote: At 05:46 PM 10/15/2011, Jim Palfreyman wrote... http://nbcu.mo2do.net/s/18488/29?itemId=tag:dvice.com,2011://3.83661fullPageURL=/archives/2011/10/speedy-neutrino.php Comments please! What an annoying website. Here's a better source, without all the unnecessary pagination and pablum. http://arxiv.org/abs/1110.2685 and the original one in a more readable form: http://dvice.com/archives/2011/10/speedy-neutrino.php ___ time-nuts mailing 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] Speedy neutrino puzzle solved
On 10/16/2011 02:39 AM, Javier Herrero wrote: El 16/10/2011 02:14, iov...@inwind.it escribió: And further, what the author states, in other words, would mean that the two clocks at Earth, in the frame in which the measurement was made, were off by 60 ns, isn't it? More or less :) I'm also not sure of the accuracy of the phrase The clocks in the OPERA experiment are orbiting the earth in GPS satellites, since as far as I've understood the GPS is used to use common view for comparison of the Cs clocks. And it seems that the author does not know that relativity has already been taken into account in the GPS system. A first compensation of relativity is done by shifting the frequency such that the fixed satellite would use 10,23 MHz as observed from the earth. This frequency is used in 120, 154, 1 and 1/10 multiples for carries and chip-rate of pseudo-random noise in the set of gears providing time distribution. The one relative effect which they maybe didn't account for is the Sagnac effect, which Tom estimated being about 2.3 ns which matches the difference found in the time-difference testing. This effect comes from the spinning of the earth. Much of the effects is first degree compensated when doing a common view comparision, and the GPS clock is only a transfer clock, not the clock of the measurement. A much more detailed analysis would be required of the timing system then provided by that 4 page paper, detailing the processes in the GPS receivers, post-processing etc. Also, a full review of the timing system would need to analyse the internal distribution system and verify that on both sites. Also, the timing of the neutrinos in the detectors and their location when detected etc also needs to be looked at. So far, I have only been looking at this quickly and the reasonability of things being done correctly. Both the main paper and the PTB preliminary report is unsatisfactory in the details for full analysis, but they seem reasonable. I'm of the same opinion as Magnus: I do not think that this paper will bebunk the OPERA one, not even a little :) Indeed. It was a very sloppy attempt. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Question about KE5FX Tools - PhaseNoise Tool
Message: 4 Date: Fri, 14 Oct 2011 18:17:06 -0700 From: John Miles jmi...@pop.net To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Subject: Re: [time-nuts] Prologix GPiB LAN 7470 printing problem Message-ID: 000501cc8ad8$28033690$7809a3b0$@pop.net Content-Type: text/plain; charset=us-ascii Hi group, just got a Prologix LAN interface and tried to get some printouts from my Anritsu MS6804A but it didnt works. Phase Noise Spectrum Surveillance prgs works fine but 7470.exe allways tells me communication error 0x02 when I request a plot. Communication to the Anritsu works cause it beeps like I would press the copy (print) key on the device but there didnt came any data to the 7470 emulator. The Anritsu offers the following devices for printing in its setup: HP2225 UA455A MC8104A ESC/P I tried all but none of them works. Any idea? I'm not familiar with any of those, actually. In general if the 7470.htm help file doesn't mention that you can request plots from a specific instrument model, then host-requested plots will not work with that instrument. You'll need to use Acquire-Wait for device-initiated plot and hit the PLOT button on the instrument's front panel... and that, in turn, will require you to configure the instrument for HPGL output to an HP 7470A/7475A or similar plotter. A quick Google suggests that the units you mention are either printers or non-HPGL plotters. 7470.exe will either do nothing or possibly crash outright if you try to send anything but HPGL traffic to it, so your best bet may be to try the evaluation version from http://www.printcapture.com and see if their Epson support works with the ESC/P output option. (It should work with the Prologix USB adapter but I'm not sure about the LAN adapter.) -- john, KE5FX Hi John, thank you for your suggestions. Im in between fixing of the problem together with Prologix support. I have a question about your PhaseNoise tool handling: As I tried a test using my Anritsu spec I got strange results. The following happened: I didnt connect any signal source to get the noise of the instrument only and set the carrier to 425MHz. As signal strenght I put in -140dBm and connected a 50Ohm dummy resistor to the instruments input. Offset-range was set to 30-1000Hz. As expected I got a horizontal line at -127dBm from 10-100Hz. Unexpectedly level changed from 100-200Hz as a falling curve down to -132dBm and went on horizontaly further at this level to 1kHz. During the measurement I observed the instrument and saw that it switched from RBW 10Hz to 100Hz so that I guess thats the reason for the descending level between 100 and 200Hz f-offset. So the observed effect seems to be a property of the Anritsu instrument. Similar happened between 1-10kHz and so on. My question: How can I adjust that offset to get a smooth measuring result? Thank you for your answer Regards Peter, DG4EK ___ time-nuts mailing 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] Reverse engineering circuit boards (was Spectracom 8182 Netclock/2)
I have used a company in Wyoming called Bomarc Services to reverse engineer boards. They work for dirt cheap and do an excellent job. If you let them put the results in their resale library, they work for cheaper than dirt. ___ time-nuts mailing 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] Rapco 1804M - serial problems?
I've just got a Rapco 1804M and while it works, within the limits of my antenna placement, the RS-232 serial out doesn't read very well, and seems to have incorrect characters. The voltage levels look OK, and the terminal emulation program is set to 4800 baud, 8-bit, no parity, one stop bit, no flow control. I've tried other combinations. As near as I can measure, the baud rate is 4800. Here's some sample output: _ UTC Time : 16:65:19 16/10?1q UTC Time : 16:25:20 16/10/11 Position : 53 54.406 N 002 12.075 W 0239 M PDOP : 02 Sat PRN : 28,19,32,01,1122 Sat levål : 00,12,13,06,05,03 Fix, Mode : 2D , Coarse UTC Time : 16:25:21 16/10/11 UTC Time : 16:25:22 16/10/11 UTC Time : 16:25:23 16/10?11 UTC Time : 16:25:24 16/10/11= UTC Ti}e : 16:25:25 16/10?11 UTC Time : 16:25:26 16/10?11 _ The same serial port works correctly with 9600 baud Garmin signal, and I don't have any other available computers with spare RS-232 ports I can test against. Am I missing the obvious, or is there something wrong with the serial port? I do appreciate that the serial port isn't critical to the correct operation of the 1804M, but this has cast doubts about this particular unit into my mind! Thanks, David GM8ARV -- 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] Reverse engineering circuit boards (was Spectracom 8182 Netclock/2)
On 10/16/2011 06:28 PM, Mark Sims wrote: I have used a company in Wyoming called Bomarc Services to reverse engineer boards. They work for dirt cheap and do an excellent job. If you let them put the results in their resale library, they work for cheaper than dirt. What would dirt cheap and cheaper than dirt cheap mean in real terms? An examples? Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Rapco 1804M - serial problems?
Le 16/10/2011 18:34, David J Taylor a écrit : I've just got a Rapco 1804M and while it works, within the limits of my antenna placement, the RS-232 serial out doesn't read very well, and seems to have incorrect characters. The voltage levels look OK, and the terminal emulation program is set to 4800 baud, 8-bit, no parity, one stop bit, no flow control. I've tried other combinations. As near as I can measure, the baud rate is 4800. Here's some sample output: _ UTC Time : 16:65:19 16/10?1q UTC Time : 16:25:20 16/10/11 Position : 53 54.406 N 002 12.075 W 0239 M PDOP : 02 Sat PRN : 28,19,32,01,1122 Sat levål : 00,12,13,06,05,03 Fix, Mode : 2D , Coarse UTC Time : 16:25:21 16/10/11 UTC Time : 16:25:22 16/10/11 UTC Time : 16:25:23 16/10?11 UTC Time : 16:25:24 16/10/11= UTC Ti}e : 16:25:25 16/10?11 UTC Time : 16:25:26 16/10?11 _ The data is nearly all good, so probably not a rs232 rate issue. Looking at the transformations in the above data, / = ? 1 =q , = CR = = m = } they are all single/multiple bit flips in the top nibble of the character hex value. Maybe it's a UART that has hickups. I couldn't find a schematic, but may be worth looking to see what's connected to the RS232 tranceiver chip.. The same serial port works correctly with 9600 baud Garmin signal, and I don't have any other available computers with spare RS-232 ports I can test against. Am I missing the obvious, or is there something wrong with the serial port? I do appreciate that the serial port isn't critical to the correct operation of the 1804M, but this has cast doubts about this particular unit into my mind! Thanks, David GM8ARV ___ time-nuts mailing 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] Cable delay correction for Tbolt Cs substitude
Anyone know what the propagation delay temperature coefficient is for RG6U coax and how much it varies between different brands of cable? In my efforts to improve the Tbolt's performance to make it into a better Cs substitute, test suggest that the temperature coefficient of the antenna lead-in cable's propagation delay is contributing to diurnal errors. Anyone have a idea for a SIMPLE cheap voltage controlled delay line that can be changed by a few ns as a function of the outside air temperature? As an alternative, Mark, want to consider adding another LadyHeather feature that tweaks the Tbolt's cable delay value as a function of the outside temperature? If interested, I have a couple ideas of how to get the outside temperature to LadyHeather. ws ___ time-nuts mailing 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] Reverse engineering circuit boards (was Spectracom 8182 Netclock/2)
I seem to remember that their rate was around $20 and hour... half that if you let them put the results in their for sale library. They did a 6x8 four layer board with components on each side for less than $250. It had a off-the-shelf DC-DC converter brick on it... the board came back with the brick de-potted and a schematic of its internals. I just tried their web site and it was not responding... hopefully they are not now extinct. ___ time-nuts mailing 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] Cable delay correction for Tbolt Cs substitude
Using the cable delay message is probably not a good idea... it resets the internal filters and state every time you change it. ___ time-nuts mailing 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] Reverse engineering circuit boards (was Spectracom 8182 Netclock/2)
On 10/16/2011 07:57 PM, Mark Sims wrote: I seem to remember that their rate was around $20 and hour... half that if you let them put the results in their for sale library. They did a 6x8 four layer board with components on each side for less than $250. It had a off-the-shelf DC-DC converter brick on it... the board came back with the brick de-potted and a schematic of its internals. Decent enough! I just tried their web site and it was not responding... hopefully they are not now extinct. Hope for the better. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Cable delay correction for Tbolt Cs substitude
Thanks John Any chance using 75 ohm cable (as suggested in the Tbolt manual) like RG6U, when used in a 50 Ohm system could be orders of magnitude worse than LMR-400? Sounds like may be time to do some controlled cable experiments comparing different cables. I do know that Cheapie GPS timing antenna's can have a large Phase variation when the Sun hits them. I had one antenna that changed 25 ns every day around Noon time. That is when I changed over to a Symmetricom 58532A antenna and things improved 10 fold. With the new antenna the phase error change is now down at least near the GPS noise level, but it seems to still have some antenna system temperature effects. Maybe a silly question but how can a 1.5GHz preamp and filter change the phase over so many cycles? Does anyone ever add a temperature controller on the antenna? Maybe that should be my next test. ws ** from John Ackermann N8UR I did some very rough measurements last summer with. Run of LMR-400 that was laying on the roof in the hot Georgia sun. Using a network analyzer to ping the cable I found the day vs. night delay difference was pretty much in the noise. I'll see if I can find the details and if so will post them. I found via google a brief paper from Haystack that measured LMR-400 and LMR-240 and found in the range of -11 to +17 ppm/K of the total cable delay. They note that 9 ppm/K is about 3ps/degree in 100M of cable: http://www.haystack.mit.edu/tech/vlbi/mark5/mark5_memos/069.pdf However, there's another possible tempo contributor that I suspect could be a significant contributor, and that's the preamp up in the antenna, particularly if it has a bandpass filter. It wouldn't surprise me at all if preamp/BPF tempo was noticeable. John On Oct 16, 2011, at 1:32 PM, WarrenS wrote: Anyone know what the propagation delay temperature coefficient is for RG6U coax and how much it varies between different brands of cable? In my efforts to improve the Tbolt's performance to make it into a better Cs substitute, test suggest that the temperature coefficient of the antenna lead-in cable's propagation delay is contributing to diurnal errors. Anyone have a idea for a SIMPLE cheap voltage controlled delay line that can be changed by a few ns as a function of the outside air temperature? As an alternative, Mark, want to consider adding another LadyHeather feature that tweaks the Tbolt's cable delay value as a function of the outside temperature? If interested, I have a couple ideas of how to get the outside temperature to LadyHeather. ws ___ ___ time-nuts mailing 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] Cable delay correction for Tbolt Cs substitude
I wouldn't think the cable type will make an order-of-magnitude difference. Referenced in the Haystack note is another paper that goes through the theoretical derivation that produced the expected results column. I think it's the same URL but 067.pdf as the file name. John On Oct 16, 2011, at 2:21 PM, WarrenS warrensjmail-...@yahoo.com wrote: Thanks John Any chance using 75 ohm cable (as suggested in the Tbolt manual) like RG6U, when used in a 50 Ohm system could be orders of magnitude worse than LMR-400? Sounds like may be time to do some controlled cable experiments comparing different cables. I do know that Cheapie GPS timing antenna's can have a large Phase variation when the Sun hits them. I had one antenna that changed 25 ns every day around Noon time. That is when I changed over to a Symmetricom 58532A antenna and things improved 10 fold. With the new antenna the phase error change is now down at least near the GPS noise level, but it seems to still have some antenna system temperature effects. Maybe a silly question but how can a 1.5GHz preamp and filter change the phase over so many cycles? Does anyone ever add a temperature controller on the antenna? Maybe that should be my next test. ws ** from John Ackermann N8UR I did some very rough measurements last summer with. Run of LMR-400 that was laying on the roof in the hot Georgia sun. Using a network analyzer to ping the cable I found the day vs. night delay difference was pretty much in the noise. I'll see if I can find the details and if so will post them. I found via google a brief paper from Haystack that measured LMR-400 and LMR-240 and found in the range of -11 to +17 ppm/K of the total cable delay. They note that 9 ppm/K is about 3ps/degree in 100M of cable: http://www.haystack.mit.edu/tech/vlbi/mark5/mark5_memos/069.pdf However, there's another possible tempo contributor that I suspect could be a significant contributor, and that's the preamp up in the antenna, particularly if it has a bandpass filter. It wouldn't surprise me at all if preamp/BPF tempo was noticeable. John On Oct 16, 2011, at 1:32 PM, WarrenS wrote: Anyone know what the propagation delay temperature coefficient is for RG6U coax and how much it varies between different brands of cable? In my efforts to improve the Tbolt's performance to make it into a better Cs substitute, test suggest that the temperature coefficient of the antenna lead-in cable's propagation delay is contributing to diurnal errors. Anyone have a idea for a SIMPLE cheap voltage controlled delay line that can be changed by a few ns as a function of the outside air temperature? As an alternative, Mark, want to consider adding another LadyHeather feature that tweaks the Tbolt's cable delay value as a function of the outside temperature? If interested, I have a couple ideas of how to get the outside temperature to LadyHeather. ws ___ ___ time-nuts mailing 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] Cable delay correction for Tbolt Cs substitude
Its merely a calculation of the change in inductance due to the temperature induced change in skin depth due to the resistivity tempco of the inner conductor wich varies the inductance per unit length. Since RG6 uses a copper plated steel inner conductor there may be significant differences in the inductance tempco should the plating thickness not be much greater than the skin depth (most likely at lower frequencies). The thermal expansion of the inner conductor will also be smaller than that of a copper conductor. Thus the delay tempco of RG6 may differ somewhat from that of LMR400. Bruce John Ackermann N8UR wrote: I wouldn't think the cable type will make an order-of-magnitude difference. Referenced in the Haystack note is another paper that goes through the theoretical derivation that produced the expected results column. I think it's the same URL but 067.pdf as the file name. John On Oct 16, 2011, at 2:21 PM, WarrenSwarrensjmail-...@yahoo.com wrote: Thanks John Any chance using 75 ohm cable (as suggested in the Tbolt manual) like RG6U, when used in a 50 Ohm system could be orders of magnitude worse than LMR-400? Sounds like may be time to do some controlled cable experiments comparing different cables. I do know that Cheapie GPS timing antenna's can have a large Phase variation when the Sun hits them. I had one antenna that changed 25 ns every day around Noon time. That is when I changed over to a Symmetricom 58532A antenna and things improved 10 fold. With the new antenna the phase error change is now down at least near the GPS noise level, but it seems to still have some antenna system temperature effects. Maybe a silly question but how can a 1.5GHz preamp and filter change the phase over so many cycles? Does anyone ever add a temperature controller on the antenna? Maybe that should be my next test. ws ** from John Ackermann N8UR I did some very rough measurements last summer with. Run of LMR-400 that was laying on the roof in the hot Georgia sun. Using a network analyzer to ping the cable I found the day vs. night delay difference was pretty much in the noise. I'll see if I can find the details and if so will post them. I found via google a brief paper from Haystack that measured LMR-400 and LMR-240 and found in the range of -11 to +17 ppm/K of the total cable delay. They note that 9 ppm/K is about 3ps/degree in 100M of cable: http://www.haystack.mit.edu/tech/vlbi/mark5/mark5_memos/069.pdf However, there's another possible tempo contributor that I suspect could be a significant contributor, and that's the preamp up in the antenna, particularly if it has a bandpass filter. It wouldn't surprise me at all if preamp/BPF tempo was noticeable. John On Oct 16, 2011, at 1:32 PM, WarrenS wrote: Anyone know what the propagation delay temperature coefficient is for RG6U coax and how much it varies between different brands of cable? In my efforts to improve the Tbolt's performance to make it into a better Cs substitute, test suggest that the temperature coefficient of the antenna lead-in cable's propagation delay is contributing to diurnal errors. Anyone have a idea for a SIMPLE cheap voltage controlled delay line that can be changed by a few ns as a function of the outside air temperature? As an alternative, Mark, want to consider adding another LadyHeather feature that tweaks the Tbolt's cable delay value as a function of the outside temperature? If interested, I have a couple ideas of how to get the outside temperature to LadyHeather. ws ___ ___ time-nuts mailing 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] Thunderbolt error?
Hi gang I'm getting an error message of vco near rail or vco at rail. Is this saying my thunderbolt is dying or can this be fixed? -Rix Seacord ___ time-nuts mailing 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] Cable delay correction for Tbolt Cs substitude
Sounds like its time to do some testing and see what the effect is on the actual hardware. 1) Heat and cool the Tbolt box and see if that effects THIS Phase delay, maybe by way of its internal GPS amp/BPF. In the past I have not seen a need to use LH's temperature controller on a Tbolt that is driving an external Dual oven Osc or a temperature stabilized Rb like this Tbolt is. 2) Place an extra 50 ft of RG6 between the Antenna and the Tbolt inside an oven, then heat and cool it. 3) Put the Roof top antenna in an RF transparent box with a heater. too much fun ws Griffiths bruce.griffiths at xtra.co.nz wrote: It's merely a calculation of the change in inductance due to the temperature induced change in skin depth due to the resistivity tempco of the inner conductor which varies the inductance per unit length. Since RG6 uses a copper plated steel inner conductor there may be significant differences in the inductance tempco should the plating thickness not be much greater than the skin depth (most likely at lower frequencies). The thermal expansion of the inner conductor will also be smaller than that of a copper conductor. Thus the delay tempco of RG6 may differ somewhat from that of LMR400. Bruce *** John Ackermann N8UR wrote: I wouldn't think the cable type will make an order-of-magnitude difference. Referenced in the Haystack note is another paper that goes through the theoretical derivation that produced the expected results column. I think it's the same URL but 067.pdf as the file name. John On Oct 16, 2011, at 2:21 PM, WarrenS wrote: Thanks John Any chance using 75 ohm cable (as suggested in the Tbolt manual) like RG6U, when used in a 50 Ohm system could be orders of magnitude worse than LMR-400? Sounds like may be time to do some controlled cable experiments comparing different cables. I do know that Cheapie GPS timing antenna's can have a large Phase variation when the Sun hits them. I had one antenna that changed 25 ns every day around Noon time. That is when I changed over to a Symmetricom 58532A antenna and things improved 10 fold. With the new antenna the phase error change is now down at least near the GPS noise level, but it seems to still have some antenna system temperature effects. Maybe a silly question but how can a 1.5GHz preamp and filter change the phase over so many cycles? Does anyone ever add a temperature controller on the antenna? Maybe that should be my next test. ws ** from John Ackermann N8UR I did some very rough measurements last summer with. Run of LMR-400 that was laying on the roof in the hot Georgia sun. Using a network analyzer to ping the cable I found the day vs. night delay difference was pretty much in the noise. I'll see if I can find the details and if so will post them. I found via google a brief paper from Haystack that measured LMR-400 and LMR-240 and found in the range of -11 to +17 ppm/K of the total cable delay. They note that 9 ppm/K is about 3ps/degree in 100M of cable: http://www.haystack.mit.edu/tech/vlbi/mark5/mark5_memos/069.pdf However, there's another possible tempo contributor that I suspect could be a significant contributor, and that's the preamp up in the antenna, particularly if it has a bandpass filter. It wouldn't surprise me at all if preamp/BPF tempo was noticeable. John On Oct 16, 2011, at 1:32 PM, WarrenS wrote: Anyone know what the propagation delay temperature coefficient is for RG6U coax and how much it varies between different brands of cable? In my efforts to improve the Tbolt's performance to make it into a better Cs substitute, test suggest that the temperature coefficient of the antenna lead-in cable's propagation delay is contributing to diurnal errors. Anyone have a idea for a SIMPLE cheap voltage controlled delay line that can be changed by a few ns as a function of the outside air temperature? As an alternative, Mark, want to consider adding another LadyHeather feature that tweaks the Tbolt's cable delay value as a function of the outside temperature? If interested, I have a couple ideas of how to get the outside temperature to LadyHeather. ws __ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt error?
Rix If you are using LadyHeather, Post or send me a screen shot using W S Cr Maybe just that the min or max Dac values are not set to - + 5V, or something else easily fixed. ws [time-nuts] Thunderbolt error? Rix Seacord eseacord at verizon.net Hi gang I'm getting an error message of vco near rail or vco at rail. Is this saying my thunderbolt is dying or can this be fixed? -Rix Seacord ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt error?
Warren I may have jumped the gun on this. I cycled the power a few times and it appears to work. Note the temperature never seems to change. It sometimes goes bonkers then settles down again. Attached is the screen shot Thanks much Rix On 10/16/2011 3:47 PM, WarrenS wrote: Rix If you are using LadyHeather, Post or send me a screen shot using W S Cr Maybe just that the min or max Dac values are not set to - + 5V, or something else easily fixed. ws [time-nuts] Thunderbolt error? Rix Seacord eseacord at verizon.net Hi gang I'm getting an error message of vco near rail or vco at rail. Is this saying my thunderbolt is dying or can this be fixed? -Rix Seacord ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Rix Seacord (K2AVP) Putnam County Radio Officer 22 Austin Rd Mahopac, NY 10541 Home 845-628-0892 Cell 914-262-9186 attachment: tbolt.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] Measuring ADEV using TBolt-Tic tester
Hi Warren, Something to be careful about when doing what you suggest is that the two Tbolts will not switch birds at the same time, so need to not use that part of the data if you want to remove the effect of the GPS. Treat that part like outliners. Right that is a problem when looking at combined measurements. If you use per satellite measurements instead, ie 'Clock bias per satellite' in 0x8F-A7 or doppler in 0x5A, then you are fine as long as you compare 'Common view' satellites. What is nice is also that you can use all satellites that are tracked on both receivers. The 2Tbolt-system is really a degenerated Common View time transfer system, with both receivers beening colocated and using the same GPS antenna signal. Moving the receivers to different time-nut labs, we have a traditional time-transfer system. Where we perhaps only lack L2 measurements, compared to the serious time tranfer systems used by national labs. http://tf.nist.gov/time/commonviewgps.htm -- Björn To check for Tbolt noise floor, Good idea to use just one external one and an internal one as long as it has a good low noise Osc in it. Can using the 10 MHz output of the internal one to drive the input of the external one. Also to remove as much variation as possible, put BOTH of them in the disable mode (but not holdover mode) and manually adjust their setting so they both read about the same values for their Phase and freq. Now you're suggesting making a better Tbolt Tic by using two and comparing their differences. Have to think that over a little, sounds like a good plan, But so far have not seen anyone else that will even try it with one. Thanks, I'm now thinking about how to use two external Tbolts in a setup more like a DUAL Phase thing. The GPS signal can be the Offset osc and therefore will have little effect. The GPS will just act as a near zero offset frequency osc, and watching the phase differences between the two Tbolts, should work fine. Thanks, so many fun things still to play with. ws * Hi Warren, What is not too clear is how much of that is due to the Tbolt engine and how much is the GPS Reference. Do you have two working Tbolts with their orginal oscillator removed? From what I've seen in my test, a large amount of that noise floor is due to the GPS. I think a dual Tbolt configuration would eliminate GPS instabilities and rely more on the house standard. As proposed in previous email. -- Björn * snip I propose an experiment with two Tbolts running from the same antenna and sharing the same oscillator, ie at least one of the Tbolts modified to accept external 10MHz. This would take out most/all GPS system errors, leaving receiver measurement noise. When speaking of 1-shot resolution I think a dual-Tbolt configuration, with one driven by the DUT and the other by the house standard, is closer to a fair comparison with a TIC instrument. Since this configuration will eliminate the GPS system and propagation errors and the TIC is always limited by the house standard. Does anyone have two working Tbolts modified for external oscillator available for testing? I have one Tbolt and a loaner unit from a friend. I am not very keen on modifying the two I have in my lab right now. kind regards, Björn ___ time-nuts mailing 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] Question about KE5FX Tools - PhaseNoise Tool
As I tried a test using my Anritsu spec I got strange results. The following happened: I didnt connect any signal source to get the noise of the instrument only and set the carrier to 425MHz. As signal strenght I put in -140dBm and connected a 50Ohm dummy resistor to the instruments input. Offset-range was set to 30-1000Hz. As expected I got a horizontal line at -127dBm from 10-100Hz. Unexpectedly level changed from 100-200Hz as a falling curve down to - 132dBm and went on horizontaly further at this level to 1kHz. During the measurement I observed the instrument and saw that it switched from RBW 10Hz to 100Hz so that I guess thats the reason for the descending level between 100 and 200Hz f-offset. So the observed effect seems to be a property of the Anritsu instrument. Similar happened between 1-10kHz and so on. My question: How can I adjust that offset to get a smooth measuring result? Correct, you'd expect to see a flat line when measuring the spectrum analyzer's noise floor with no signal applied. Because the noise is displayed after being normalized to a 1-Hz bandwidth, the RBW shouldn't matter. Some analyzer models behave this way, but some don't, and frankly I'm not sure why. It's probably related to the proportion of the 'grass' that arises from noise in stages beyond the last RBW filter. If most of the analyzer's internal noise passes through the IF filter(s), then the 1-Hz normalization should result in a reasonably flat trace. To the extent the noise floor is influenced by stages beyond the last IF filter, it will appear to drop off in the higher decades. Does your measurement look like the attached example, where a Tektronix 494AP is compared to an HP 8566B? For this screenshot, I held down SHIFT while opening the files to keep the program from overlapping and blending between the decades, and I used ctrl-0 to disable all trace smoothing. I'm pretty sure that differences in gain distribution are responsible for the fact that the 8566B trace is relatively flat compared to the 494AP. One obvious thing to check -- does the trace remain visible within the graticule area while the measurement runs? If it is ever clipped near the top or bottom of the display, the results won't be valid. Also, the recommended way to use PN.EXE to measure the RF noise floor is described in the third-to-last FAQ entry at http://www.ke5fx.com/gpib/faq.htm if you haven't already seen it. An amplitude of -140 dBm might be clamped by the analyzer's firmware to a value that it considers more reasonable, so I'd use something like -60 dBm instead. The exact value isn't important as long as the noise trace isn't clipped. -- john, KE5FX attachment: RF_floor.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] Thunderbolt error?
Rix Nothing looks wrong in that snap Shot Your osc (which is the main cause of the out of range error) is working fine and under control and has near zero volts on it's EFC. Take a look at the screen when you key , that has the screen with the Max and min DAC setting info on it. Should be +5 and -5 (set with N -5 Cr and x 5 Cr) Also can use F A command to turn on the Altitude filter If it misses up again, use the \ key to get an automatic screen shot save without it first updating. If bonkers is about 1 deg, maybe you have the low resolution Temp sensor chip (It has about 1/2 deg C resolution). That does not really matter or effect anything important unless you are doing temperature control with LH. If the temp never changes, then likely the DS?? surface mount 8 pin temp sensor chip is broken and should be replace Do note the way you have the temp plot set up (Zero offset and low gain) you will only be able to see large changes on the plot. Have fun ws *** Warren I may have jumped the gun on this. I cycled the power a few times and it appears to work. Note the temperature never seems to change. It sometimes goes bonkers then settles down again. Attached is the screen shot Thanks much Rix *** On 10/16/2011 3:47 PM, WarrenS wrote: Rix If you are using LadyHeather, Post or send me a screen shot using W S Cr Maybe just that the min or max Dac values are not set to - + 5V, or something else easily fixed. ws ___ time-nuts mailing 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] Cable delay correction for Tbolt Cs substitude
Yes, at one time there was some very precision surveying antennas that were temperature controlled. I'm not sure if they were just controlling just the preamp or the whole antenna, but I got the impression that they were controlling the temperature everything inside the radome package. At one time I did some TDR measurements on a piece of coax (I think it was 100 feet of black RG59). The day/night prop time variation was under a nanosecond. Something tells me that the cable delay changes itself won't make any difference. - Does anyone ever add a temperature controller on the antenna? Maybe that should be my next test. ___ time-nuts mailing 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] Cable delay correction for Tbolt Cs substitude
Mark, Warren, That's correct. Some dual-frequency geodetic-grade GPS receivers use thermally stabilized antennas. It's one more trick in the quest for nanosecond stability and there's no reason one couldn't homebrew one. There are photos of them on the web. It would also not be hard to test, especially if you use a TEC so you can manually set the temperature way up and down over fractions to multiples of an hour. Or compare it in real time against an unstabilized sister antenna and TBolt. Good reading, performance charts graphs: http://www.ngs.noaa.gov/CORS/Articles/metrologia-2.pdf Geodetic techniques for time and frequency comparisons using GPS phase and code measurements More info at CORS and IGS sites: http://www.ngs.noaa.gov/CORS/ http://igscb.jpl.nasa.gov/ I agree on your cable comments. I used Andrew Heliax on my L1/L2 antenna back when I was running a Z-12T. At its best it was good to cm levels, way below 1 ns. http://leapsecond.com/pages/quake/panga-tvb1.gif Would it be possible to run a controlled current down the coax to maintain constant temperature 24x7? You could use its resistance as a proxy for temperature. /tvb - Original Message - From: Mark Sims hol...@hotmail.com To: time-nuts@febo.com Sent: Sunday, October 16, 2011 5:28 PM Subject: [time-nuts] Cable delay correction for Tbolt Cs substitude Yes, at one time there was some very precision surveying antennas that were temperature controlled. I'm not sure if they were just controlling just the preamp or the whole antenna, but I got the impression that they were controlling the temperature everything inside the radome package. At one time I did some TDR measurements on a piece of coax (I think it was 100 feet of black RG59). The day/night prop time variation was under a nanosecond. Something tells me that the cable delay changes itself won't make any difference. - Does anyone ever add a temperature controller on the antenna? Maybe that should be my next test. ___ time-nuts mailing 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] Cable delay correction for Tbolt Cs substitude
On 16 Oct, 2011, at 11:21 , WarrenS wrote: Does anyone ever add a temperature controller on the antenna? Maybe that should be my next test. I've seen commercial temperature-controlled antennas. Here's one: http://adriang.com/AACE-Industries/products.htm Dennis Ferguson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt error?
Warren When I had the temp set at a higher gain and the offset to center the trace, it would basically flat line then suddenly be all over the place. Are the chips available anyplace? I do have a bit of experience of soldering. Thanks again. Ewing (Rix) Seacord K2AVP Putnam County RACES Radio Officer eseac...@verizon.net 845-628-0892 Home 914-262-9186 Cell I hear and I forget I see and I remember I do and I understand On 10/16/2011 7:43 PM, WarrenS wrote: Rix Nothing looks wrong in that snap Shot Your osc (which is the main cause of the out of range error) is working fine and under control and has near zero volts on it's EFC. Take a look at the screen when you key , that has the screen with the Max and min DAC setting info on it. Should be +5 and -5 (set with N -5 Cr and x 5 Cr) Also can use F A command to turn on the Altitude filter If it misses up again, use the \ key to get an automatic screen shot save without it first updating. If bonkers is about 1 deg, maybe you have the low resolution Temp sensor chip (It has about 1/2 deg C resolution). That does not really matter or effect anything important unless you are doing temperature control with LH. If the temp never changes, then likely the DS?? surface mount 8 pin temp sensor chip is broken and should be replace Do note the way you have the temp plot set up (Zero offset and low gain) you will only be able to see large changes on the plot. Have fun ws *** Warren I may have jumped the gun on this. I cycled the power a few times and it appears to work. Note the temperature never seems to change. It sometimes goes bonkers then settles down again. Attached is the screen shot Thanks much Rix *** On 10/16/2011 3:47 PM, WarrenS wrote: Rix If you are using LadyHeather, Post or send me a screen shot using W S Cr Maybe just that the min or max Dac values are not set to - + 5V, or something else easily fixed. ws ___ time-nuts mailing 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.
