Re: [time-nuts] USB Low Cost GPS Timing Receiver
-Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von bro...@pacific.net Gesendet: Freitag, 26. November 2010 22:43 An: time-nuts@febo.com Betreff: [time-nuts] USB Low Cost GPS Timing Receiver Hi: A friend is looking for a low cost GPS receiver to set the clock in the computer that controls his telescope mount. USB would be nice but is not a requirement. For example does eBay item 130456356506 set the computer clock? This GPS receiver for the Nikon has a mini-USB connector, but when connected to my computer is not recognized. http://www.prc68.com/I/Nikon.shtml#GPS Have Fun, Brooke Clarke ___ 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] Fw: How to detect PLL lock
-Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von EB4APL Gesendet: Sonntag, 7. November 2010 14:58 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] Fw: How to detect PLL lock Roberto, The classical way is to use another phase detector with one of its inputs shifted 90º, so it becomes an amplitude detector. Then you filter its output and above certain reference you declare in-lock condition. This works well even in very noisy conditions so in this application it will function very well without much care in the implementation. Since we are neighbors I will elaborate this more in a talk with you. Regards. Ignacio, EB4APL El 06/11/2010 22:51, Roberto Barrios wrote: Sorry, the links were obviously wrong: http://www.rbarrios.com/public/_MG_6553.jpg http://www.rbarrios.com/public/_MG_6554.jpg http://www.rbarrios.com/public/_MG_6556.jpg http://www.rbarrios.com/public/_MG_6565.jpg http://www.rbarrios.com/public/_MG_6567.jpg Regards, Roberto EB4EQA From: Roberto Barrios Sent: Saturday, November 06, 2010 10:48 PM To: time-nuts@febo.com Subject: How to detect PLL lock Hello, Ive built a James Miller style GPSD with a Rockwell Jupiter, 74AC86 as phase detector and Isotemp OCXO. Division from 10Mhz to 10kHz is done with a 12F675 PIC that also outputs other frequencies and I also included a 16F88 that gives information as OCXO oven info and various GPS status indicators got from the NMEA string. Everything is built on a PCB similar to the Jupiter GPS. I built the PCB by plotting with a resistive pen directly on the copper with a plotter. It works reasonably well as compared to a Trimble thunderbolt, as per my limited knowledge. Some pictures of the result: http://www.rbarrios.com/public/_MG_6553.jpg http://www.rbarrios.com/public/_MG_6553.jpg http://www.rbarrios.com/public/_MG_6553.jpg http://www.rbarrios.com/public/_MG_6553.jpg http://www.rbarrios.com/public/_MG_6553.jpg I would also like to include PLL lock indication with a LED, but Im struggling to find a reliable indicator. Ive tried using the OCXOs control voltage, which stabilizes when the PLL is locked as an indicator, monitoring it with an ADC of the PIC. Resolution is only around 14mV because of the voltage divider before the ADC input. I cant make it react as desired to unlocks, I tried some formulas but it is always either too strict or too loose. Ive also timed the duty cycle of the 74AC68phase detector output with a timer, but I guess the granurality (10Mhz/4) is too coarse to precisely detect when its constant. For either reason, the PLL LOCK led is lit when it shouldnt or viceversa. Does anyone have a practical, easily implementable solution for the lock indicator in this vaguely-nut GPSDO, that this newbie could work out ? Ideally it would be implemented in software, but I understand this modest hardware may have severe limitations. Thank you, Roberto EB4EQA ___ 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] 5061a now look at wrong freq A1 fault
I fully agree to John's instructions. TvB should have the manual on his web site. If peeking is correct, check for phase alignement as well. Did you replace the capacitor C49 about 10 uF on Synthesizer board? If it did not fail, it will soon and start eating traces of PC board. If you need further assistance or spare parts from Germany do not hesitate to contact me offline. Hubert, DB7ME -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von John Miles Gesendet: Samstag, 27. Februar 2010 05:38 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] 5061a now look at wrong freq A1 fault I think the best policy re: initial setup of the 5061A is to follow the manual. There are clear instructions on how to set the beam current and second harmonic indications and tune the OCXO to find the central peak. If it is locked but not exactly at 5 MHz, either your C-field is grossly off, or (more likely) you are tuned to a side peak. But the beam current should be verified before worrying about that. -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Dott. Alfredo Rosati Sent: Friday, February 26, 2010 7:36 PM To: J. L. Trantham; time-nuts@febo.com Subject: Re: [time-nuts] 5061a now look at wrong freq A1 fault the problem was in the syinthesizer board A1 , the xtal oscillator 12.63 was to much aging and was at the limit of pll , now I fixed this board , now the 12.63 signal is clear and loocked , before was very noisy . But seeme there are more problem , the signal now is very close to 5MHZ but there are some difference from my rubidium and my Z3805a The 5 MHZ now is near 5 x 10-10 . Now I need to ascertain , if there are more fault , or because I have an high performance tube , I need a degausser ?? I will continue to study . all suggestion will be appreciated i5uxj ___ 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] HP 105B Modification
Depending on what you want to do and which performane is to be achieved, the first thing I woulsd do is to look at the 5061B manual. Best regards, Hubert -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Bruce Griffiths Gesendet: Montag, 7. Dezember 2009 23:17 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] HP 105B Modification Corby Dawson wrote: Ed, The easiest way is to couple out the 10Mhz from the two pins on the connector holding the 10811 into a Fet input buffer amplifier that can drive 50 ohms. There are lots of FET buffer schematics floating around. Try the radio amateurs handbook or google it. Good Luck! Corby Dawson A better way (if mechanically feasible) is to build a small 2 output distribution amplifier. Drive the distribution amplifier directly from the 10811A. Use one output to drive the divider and the other for the desired 10MHz output. The 10811A output can easily drive a couple of transformer feedback CE amplifiers connected in parallel. Most of the buffer amplifiers in the ARRL handbook have relatively high phase noise floors. FET buffers tend to be relatively noisy when the noise of the gate suppressor resistor is taken into account. Bruce ___ 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] OT: Power level reference
To all interested in this matter. There is an excellent application note on power measurement available on Agilents web site. http://cp.literature.agilent.com/litweb/pdf/5989-6255EN.pdf Fundamentals of RF and Microwave Power Measurements Another outstanding application note can be found on Rohde and Schwarz web page. http://www2.rohde-schwarz.com/file_2212/SLMESS_E.PDF voltage and power measurements. For sure this list is not complete, think of Tegam as well, but a good point to start with. To verify the output of a 30 / 50 MHz to less than might be 2 % the easiest way is to use a HP 432 powermeter with a 478A powersensor (thermistor mount)and follow the procedures given in the 436A manual. Just take a calibration factor of 99 % if not known more exactly. If you want to be more precise in test get a sensor calibrated at a higher level, and at the highest level (national institutes) you will achieve less than 0.2% fort he calibration factor. There is no easy way to have the highest precission in RF and Microwave power measurement. If you have detailed questions on this matter contact me offline and I will try to answer your question. Good luck in calibrating powersensors! Hubert DB7ME -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Adrian Gesendet: Dienstag, 1. Dezember 2009 14:25 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] OT: Power level reference Joe, the HP 434A calorimetric power meter does the trick as it works from DC to 12.4 GHz. And, it measures 10 mW to 10 W full scale. http://www.hpmemory.org/wa_pages/wall_a_page_10.htm Just scroll 2/3 down. Adrian Joseph Gray schrieb: We all have our various highly accurate frequency and perhaps time references. Is there a relatively simple and inexpensive method of making an accurate RF power level reference? If so, then what do we calibrate it with, not already having such an accurate reference? One possibility that comes to mind is an HP 436A power meter. These are abundant and usually have no sensor probes (which are expensive). They also have a built in 50MHz, 0dBm reference. However, without more fancy test equipment, I have no way to calibrate the reference, or even verify that it is accurate. Joe Gray KA5ZEC ___ 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] New question slightly off topic.
Knowing the knowledge of many members of the list I hope to find an answer to the following question. Can somebody help to identify and give hints for documentation for the following instrument. Weinschel 1103-5GPA rf power transfer standard. Basically this is a thermally insulated thermistor mount connected to a coaxial directional coupler with some means of tuning. Thank you for any help. Hubert DB7ME ___ 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] beryllium oxide
BeO furthermore had been used in some types of RF attenuators, especially for higher power, as a insulating washer for transistors (High voltage power transistors, RF terminating resistors, Thermal studs and so on. Although it is replaced nowadays in most cases by different materials, Beo can be found easily in older equipment. Hubert DB 7 ME -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Robert Atkinson Gesendet: Freitag, 16. Januar 2009 19:59 An: Discussion of precise time and frequency measurement Betreff: [!! SPAM] Re: [time-nuts] beryllium oxide I've personally seen three applications of BeO in electronics. Two, including the most common, are a possible hazzard. The most common application is RF power devices (transistors and terminating resistors). These hace a washer or slab of BeO between the semiconductor device and the mounting stud or flange. Asthis is trypically below the electrical connecting leads (often wide strips or tabs), application of excessive force between heatsink and PCB can fracture the BeO causing dust an chips/splinters. Splinters onder the skin or in the eye can cause problems as well as inhaled dust. force can be applied during manufacture / service or in an accident or if the item containing the unit is crushed. Next most common is the use in metal can semiconductors. One example are early LM78Hxx TO3 regulators. These are fairly safe as the can has to be ruptured. The third is as a block of solid BeO bonded to metal plates used to insulate conduction cooled vacuum tubes. Some power tubesmay use it internally. A big problem is that it looks like any other ceramic. In some UK equipment devices containing BeO will be marked with cornflower blue paint dot. A non-electronic application is in some (eg argon-ion) lasers. on a side note some vacuum tubes (especially cold cathode types) contain various radioactive materials. Robert G8RPI. --- On Fri, 16/1/09, Mike S mi...@flatsurface.com wrote: From: Mike S mi...@flatsurface.com Subject: Re: [time-nuts] beryllium oxide To: Discussion of precise time and frequency measurement time-nuts@febo.com Date: Friday, 16 January, 2009, 6:28 PM At 12:45 PM 1/16/2009, Lux, James P wrote... More realistically, the dangeris dust when something is physically overstressed (dropped, mounting overtightened, thermal shock). That, and if it gets ground up in trash disposal... Say someone throws it in the shredder. So, if some electronics have an IC with a BeO package, and it sits undisturbed, what's the problem? It seems to me that most, if not all, such uses would be additionally contained by heatsinks and compound, since it's the thermal conductivity properties which caused it to be used in the first place. Hard to say how much dust might be produced by dropping or overtightening. In my experience, ceramics tend to break pretty cleanly. Maybe BeO is different. Granted, the manufacturer can be expected to be biased, but Brush Ceramics claims Beryllium oxide (BeO), in solid form and as contained in finished products, presents no special health risks. They also claim Under federal regulations and most state regulations, BeO ceramic or products containing BeO ceramics that are no longer recyclable and declared solid wastes are not classified as hazardous waste due the content of BeO ceramic. ___ 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] repairing an HP 5248M crystal oscillator
The oven used for the M models is a 00105-x. Diagrams can be found as part of the HP 105 manual. This oven was used as well for 5061A and 5065A standards. Tom got a 5061 manual on his page. The first thing to check is the 110 V preheater. If you need further assistance contact me offline. Hubert DB7ME -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Dave Brown Gesendet: Montag, 8. Dezember 2008 20:24 An: Discussion of precise time and frequency measurement Betreff: [!! SPAM] Re: [time-nuts] repairing an HP 5248M crystal oscillator If the oven in the M version of the 5245 and the 5248 is the same then I have some notes here re pulling it apart etc. I have a 5245M and had to replace a buffer amp transistor in the oven some years ago. The series regulator in the 'always on' power supply failed short and took it out - like the good little fast three legged fuse that it was. I recommend that over voltage protection be added and a more rugged regulator pass transistor be fitted to the power supply while you have it on the bench, just in case. The 5248 supply may have these matters attended to- not sure. DaveB, NZ - Original Message - From: Dave M [EMAIL PROTECTED] To: time-nuts@febo.com Sent: Tuesday, December 09, 2008 6:04 AM Subject: Re: [time-nuts] repairing an HP 5248M crystal oscillator You can get an excellent PDF copy of the 5245M manual from Artek (http://artekmed.startlogic.com/page3.html) for only $10 US. They do good work there. -- Dave M Life is like a roll of toilet paper; the closer it gets to the end, the faster it goes. The oven on a 5248M is not working properly. I have the schematics for 48L however not the M. Does anyone have a schematic for an M model? The oven light comes on and dims, however the instrument appears to be temperature sensitive. I believe this is a double oven unit. Thanks, Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.9.15/1835 - Release Date: 7/12/2008 16:56 ___ 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] Assistance with GCRU-D.
-Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von marks twotoe.com Gesendet: Sonntag, 27. April 2008 14:35 An: time-nuts@febo.com Betreff: [time-nuts] Assistance with GCRU-D. Dear Timelords, RE: I have 2 ways of recovering my only reference. The first is reflash the chip with a binary image. The second is upload the hex image through the serial port. I have neither image. No one has been forthcoming with assistance from this group. Through other channels I have tried contacting people who profess to know all about these units. They are refusing to help, outright, only releasing such wisdom about shutting the gate after the horse has bolted. And now the supplier who has conveniently dropped off the face of the earth. So I am left with an expensive paper weight. What am I supposed to think about all of this? Mark Stephens VK2HMC ___ 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] Another manual request: Rohde Schwarz SMG?
Request a download from your RS representative or contact RS in Germany. Most manuals can be made available for download. Best regards, Hubert DB7ME -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Paul Boven Gesendet: Donnerstag, 22. März 2007 10:54 An: time-nuts@febo.com Betreff: [time-nuts] Another manual request: Rohde Schwarz SMG? Hi everyone, Last weekend I picked up a RS SMG signal generator (100kHz-1GHz) at a Ham-fest. It works great, and after a bit of puzzling, I've worked out how to operate it, but there is one thing that keeps eluding me: how do you turn on the LCD backlight? The RS brochures from back then all show the device with nicely backlit displays. Would it require one of the 'special' codes that RS was (is?) using in their user interface? The displays are rather hard to read at the moment. Of course I've already looked at Bama, some other manual sites and Googled around, but no luck so far. So if someone could please tell me how to switch the lights on? Of course, a complete manual would also be very welcome. Regards, Paul Boven. 73 de PE1NUT ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
AW: [time-nuts] FTS 4060 Op Manual
Does anyone have diagrams for the cesium module? Hubert DB7ME -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Had Gesendet: Montag, 25. April 2005 19:24 An: time-nuts-febo.com Betreff: [time-nuts] FTS 4060 Op Manual Quick note to my fellow nuts I have posted the Operations manual for the FTS 4060 C-Beam at the following address www.to-way.com/tf.html I will try and add other interesting items as I have time. Best to all, Had, K7MLR ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
AW: [time-nuts] HP 10811A vs 10811-60111
Sorry for page flipped. Attached pdf is for 10811-60111 Best regards Hubert DB7ME -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von David Kirkby Gesendet: Samstag, 23. April 2005 16:32 An: Discussion of precise time and frequency measurement Betreff: [time-nuts] HP 10811A vs 10811-60111 Can anyone tell me the difference between the two above oscillators? I have the manual for the 97page manual (page 2 is upside down), but it does not mention the latter. However, I think I have seen a small couple of page document somewhere which listed the 10811-60111 as having no specification for phase noise, and so therefore not an ideal choice for a low phase noise oscillator. One might as well start with something that is specified for a low phase noise. I can't however now find the exact spec of the 10811-60111. Can anyone give me it? I won an auction for a 10811A on eBay and the seller said I could have a 10811-60111 for the same price if I wanted it too. I said no, I wanted the 10811A, but he has sent me the 10811-60111 instead. Is the 10811-60111 inferior? How does it differ from the 10811A? -- Dr. David Kirkby, G8WRB Please check out http://www.g8wrb.org/ of if you live in Essex http://www.southminster-branch-line.org.uk/ ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts Seiten aus HP10811-Specs.pdf Description: Adobe PDF document ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
AW: [time-nuts] homebrew atomic reference oscillator?
Bob, Probably it is possible to build an atomic frequency reference at home. First of all you have to decide which type of atomic standard you desire to construct. Cs, Rb, H2, NH3, etc. active or passive and so on. Now theoretical construction starts. Afterwards you have to find sources for all the materials needed. Soon you will end up at the price of a brand new Cs Standard. The next and most important point to my opinion is will I be able to finish the project. Do I have the expertise to solve all difficulties involved. Although its a nice idea I doubt the final success. For sure its possible to improve existing used instruments, but thats much less work than engineering a complete instrument. Hubert DB7ME -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Robert Aurand Gesendet: Montag, 18. April 2005 16:18 An: time-nuts@febo.com Betreff: [time-nuts] homebrew atomic reference oscillator? Asking this question just out of curiosity: Is it at all feasible to home build an atomic standard? I guess it would be Rb and not Cs. What are the difficulties that would be encountered? Bob K3VOT ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
AW: [time-nuts] Strange effect with C-Field change -- and a bit ofdata
Does anyone have a datasheet on 71xx FTS tubes. Any information is helpful. Thank you in advance Hubert -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Chuck Harris Gesendet: Sonntag, 27. März 2005 15:50 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] Strange effect with C-Field change -- and a bit ofdata John Ackermann N8UR wrote: Chuck Harris wrote: I remember reading an advertisement from FTS many moons ago that said they had for sale higher quality replacement tubes for 5060's, 5061's, and 5062's. Your replacement tube is most probably one of those tubes. Remember, FTS was a direct competitor for HP's line of C-Beams, and as such they coveted all aspects of HP's C-Beam market. -Chuck Yes, in fact FTS (or Symmetricom or whatever they are this week) still advertises their replacement tubes for the HP units. Interestingly, they have an 8 year warranty, so FTS must have been able to improve the reliability along the way. The FTS tubes are so good, that I always expect the ones I find to work! I have brought up several that were more than 15 years old. Try that with an HP tube. -Chuck ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
AW: AW: [time-nuts] Strange effect with C-Field change
Hi John, I saw similar outliers running especially Motorola GPS receivers in the vicinity to mobile telephones. Shielding is not sufficient. What I see in your data plot is a drifting oscillator until the receiver tries to find a new satellite configuration. (sudden jump upwards). After some time the receiver just changes phase. At the moment of relock (sudden jump downwards) the mobile or whatever source of distortion to the receiver is removed. Might be the receiving antenna was covered, by whatever material you can imagine. The 5061A did not loose phase during this period of time. Now its time to verify, why the receiver did not work. Hubert -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von John Ackermann N8UR Gesendet: Donnerstag, 24. März 2005 21:29 An: Discussion of precise time and frequency measurement Betreff: Re: AW: [time-nuts] Strange effect with C-Field change Hubert v. Bonhorst wrote: If you disregard this excursion, what happened after the change. Did frequency change as expected? Would there have been continuity of data? Which TIC do you use? Which GPS receiver do you use? How many satellites did you track? What is the minimum elevation for satellites used? I know a lot of stupid questions, but Hubert DB7ME Hi Hubert -- Yes, after this blip that lasted several hours the phase abruptly returned to just where it was. After things returned to normal, the frequency offset appears to have changed as expected (though I still need to gather data for another couple of days to precisely determine the offset). The TIC/GPS setup has been running continuously for a couple of weeks (and I've been doing similar measurements with basically this same set-up, though sometimes using a different TIC, for a couple of years). I've never seen a shift of this magnitude before. It might have been a GPS anomaly, but the coincidence of the event happening just as the C field was changed is hard to ignore. Following Tom's suggestion, the next step is to (very) carefully see if Jody might have done something else while making the change. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
AW: AW: AW: [time-nuts] Strange effect with C-Field change
Hi John, Try doubling what you have seen by disconnecting the antenna, and substituting it by a resistor that makes aprox. the same current. Hubert -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von John Ackermann N8UR Gesendet: Donnerstag, 24. März 2005 22:59 An: Discussion of precise time and frequency measurement Betreff: Re: AW: AW: [time-nuts] Strange effect with C-Field change Hubert v. Bonhorst wrote: Hi John, I saw similar outliers running especially Motorola GPS receivers in the vicinity to mobile telephones. Shielding is not sufficient. What I see in your data plot is a drifting oscillator until the receiver tries to find a new satellite configuration. (sudden jump upwards). After some time the receiver just changes phase. At the moment of relock (sudden jump downwards) the mobile or whatever source of distortion to the receiver is removed. Might be the receiving antenna was covered, by whatever material you can imagine. The 5061A did not loose phase during this period of time. Now its time to verify, why the receiver did not work. Hubert Hi Hubert -- That's a good hypothesis, but given how long this system (same receiver and antenna) has been running without ever encountering something like this makes me doubt it's a GPS anomaly, or at least a local one. A long history has shown that this receiver/antenna very seldom loses lock, and the only strong transmitters nearby are in my hamshack, and were shut down while I was out of town. Actually, right now I'm suspecting it might be a cabling problem (a possibly intermittent cable on the 1pps to the TIC that moved when the door to the 5061A control panel was opened), though it's surprising that something like that would result in more than a very transient phase shift -- I'd expect to see a transient in one data reading, not something that happened over hours. I'll be doing some tests to see if I can reproduce the jump when the cable is moved. John John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
