Re: [time-nuts] Loran C shutdown
AOPA -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Eric Garner Sent: Monday, November 16, 2009 10:44 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Loran C shutdown Does anyone know if there is any organized attempt to save LORAN? -Eric On Fri, Nov 13, 2009 at 7:11 PM, Joe Geller joegel...@roadrunner.com wrote: The Coast Guard has always been stretched very thin with limited resources for many missions. The saying was, every year we do more and more with less and less. I served in the late 70s as an electronics technician, EE, and later after Navy flight school, flying air rescue into the 80s. I was lucky to spend some time at two of the research labs, the electronics engineering center (EECEN) in Wildwood, NJ and later the electrical engineering laboratory (EELAB) in Alexandria, VA. At EELAB, I worked in other areas, but a lot of the LORAN work was done there. I remember, even back then, that some of the LORAN guys were searching hobby electronics suppliers to find obsolete chips they needed to keep the LORAN system going. I think those were LORAN C boards too, although not sure. Some new LORAN boards were being developed at the next bench over that used 6502 micros (I got to go to the micro class with the LORAN guys). Flying HU-25A Falcon jets (modified Falcon 200s that we got in 1982) across the Gulf of Mexico for some years, we had a gyro inertial system (which took some 20 minutes to align), LORAN C, and all the standard aviation navigation gear, ADF, VOR, DME, and TACAN. The Collins RNAV system used all inputs to develop position information.. As I recall, once we got hundreds of miles out into the gulf, all we had left was the inertial system (and paper charts and aluminum slide rules and later my hp-41CV with nav equations, when the RNAV when out). What we would have given for a GPS! Oh well, at least on the bright side, maybe some of those hp clocks will start to show up on the surplus market. There is a picture of the Falcon at: http://www.aero-web.org/database/aircraft/getimage.htm?id=15047 ___ 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. -- --Eric _ Eric Garner ___ 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. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13710 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13710 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] FS HP103 Precision Crystal Reference
Nice looking, no mods. $115 plus shipping from 75044. Thank you! Francesco Ledda Garland, Texas -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Magnus Danielson Sent: Sunday, November 15, 2009 9:01 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) b...@lysator.liu.se wrote: John, If a LORAN transmitter were destroyed by a terrorist team, a backup could be in operation in hours. A damaged GPS system could easily take many months or even years to fix. -John A LORAN site, with a several hundred meter high mast, a small house full of transmitter, signal generation and Cs clock(s?)... on a remote Norwegian island... would not be back online within a few hours after an attack. Regardless of location, it will take some time to restore functionality. About a year maybe. The LORAN-C station would reduce navigation in a certain area. However, since most interesting targets use GPS, it is a more interesting target. GPS is supposed to work without _any_ terrestrial support for days or weeks. I doubt that anyone can get something lethal for the SVs up in orbit without making it very obvious who they are. GPS now has lots of hot spare birds in orbit, that a instantly online with one or a few satellites going bust. The AutoNAV feature should keep it up for 180 days. It has never been used. Essentially, what if you wipe out the ground segment and needs to rebuild it. The ground segment points of GPS is fewer than the LORAN-C stations. Firing rockets to down the birds is above the average terrorist budget and infrastructure. While not all 30 GPS birds needs to go down, a significant number of them needs to for a significant system impact. Downing a single of them is sufficient for the political effect, so that is more likely. Using jammers is far more likely. It has been analyzed quite deeply. It is not impossible to locate a GPS jammer. In Iraq, they had relative high power jammers and they where able to locate them and finally take them out. That said, I think LORAN should be kept running as a backup, also with a firm commitment that it WILL KEEP running for 10+ years, giving vendors a reason to develop modern receivers. The electronics needed to support LORAN-C and eLORAN is not very complex by todays measure. Could be integrated with a GPS receiver. 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. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] The Demise of LORAN (was Re: Reference oscillator accuracy)
The bottom line is simple: the military don't need it, the FAA see no value in it; the avionics industry has discontinued the manufacturing of LORAN receivers years ago, the General Aviation community has bigger fish to fry (fight user fees); the Europen talked in the past about using LORAN for redundancy purposes, but never issued any concrete plans or requisitions. For all above reasons, LORAN is going to go. As a pilot, my personal experience about LORAN is mixed. Two times in heavy IMC, using RNAV LORAN, the LORAN went out in crytical phases of flight. This has never happened to me, with GPS. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Magnus Danielson Sent: Sunday, November 15, 2009 9:01 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) b...@lysator.liu.se wrote: John, If a LORAN transmitter were destroyed by a terrorist team, a backup could be in operation in hours. A damaged GPS system could easily take many months or even years to fix. -John A LORAN site, with a several hundred meter high mast, a small house full of transmitter, signal generation and Cs clock(s?)... on a remote Norwegian island... would not be back online within a few hours after an attack. Regardless of location, it will take some time to restore functionality. About a year maybe. The LORAN-C station would reduce navigation in a certain area. However, since most interesting targets use GPS, it is a more interesting target. GPS is supposed to work without _any_ terrestrial support for days or weeks. I doubt that anyone can get something lethal for the SVs up in orbit without making it very obvious who they are. GPS now has lots of hot spare birds in orbit, that a instantly online with one or a few satellites going bust. The AutoNAV feature should keep it up for 180 days. It has never been used. Essentially, what if you wipe out the ground segment and needs to rebuild it. The ground segment points of GPS is fewer than the LORAN-C stations. Firing rockets to down the birds is above the average terrorist budget and infrastructure. While not all 30 GPS birds needs to go down, a significant number of them needs to for a significant system impact. Downing a single of them is sufficient for the political effect, so that is more likely. Using jammers is far more likely. It has been analyzed quite deeply. It is not impossible to locate a GPS jammer. In Iraq, they had relative high power jammers and they where able to locate them and finally take them out. That said, I think LORAN should be kept running as a backup, also with a firm commitment that it WILL KEEP running for 10+ years, giving vendors a reason to develop modern receivers. The electronics needed to support LORAN-C and eLORAN is not very complex by todays measure. Could be integrated with a GPS receiver. 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. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] The Demise of LORAN (was Re: Reference oscillator accuracy)
Considering that the GPS antenna in aircrafts is mounted on top of fuselage, and that its radiation pattern is upward, it seems that a ground jammer will have an uphill battle. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of J. Forster Sent: Sunday, November 15, 2009 6:28 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) Or even into MP3 players, iPods, laptops, or cell phones. Then they'd wander all over the place too. With the latter two hosts, they could even be controlled remotely and even be fairly powerful. Would you notice having to recharge your battery a bit more often? -John === Magnus Danielson wrote: Chuck, Chuck Harris wrote: What makes you think it needs to be CW, and cannot be pulsed and chirped? May I roll in a noise jammer into the debate? Absolutely! They can be extremely power efficient. Raise the noise floor in the vicinity of the receiver, and it is all done. Probably the easiest solution would be to take a PN source and use it to drive a pulser that pulses a chirp oscillator. If you are feeling really polite, you could put a bandpass filter on the thing to protect other services. All it has to do is confuse the receiver enough so that you can't trust its readings. Depends on the goal. For some strategies, blackout is the goal, for some getting the readings go haywire every once in a while suffice. Agreed! My 9V battery suggestion was for a localized blackout device. You only have to make the receiver question each satellite's signal often enough for it to rule it out. No way is CW necessary, or even desirable. As John suggested, someone (say the Chinese) could put these things in battery operated stuffed animals, and set them up to jam a little bit now and then. After Xmas, the GPS landscape would be littered with these little stealth jammers, and willing supplicants to replace their batteries. -Chuck ___ 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. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] The Demise of LORAN (was Re: Reference oscillator accuracy)
The one the counts ARE! ;) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus Danielson Sent: Sunday, November 15, 2009 7:03 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) Francesco Ledda wrote: Considering that the GPS antenna in aircrafts is mounted on top of fuselage, and that its radiation pattern is upward, it seems that a ground jammer will have an uphill battle. Not all GPS receivers is sitting on flying airplanes. Far from it. 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. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] The Demise of LORAN (was Re: Reference oscillator accuracy)
AOPA is pushing congress to repristinate funding for LORAN. General aviation is probably the heaviest user on this Nav system. The aviation user community would love to see Nav systems with integrated LORAN and GPS capabilty, but the industry has done little in this area, due to lack of government commitment to LORAN. The FAA knows the GPS can be easily jammed, but has done nothing do push LORAN as the GPS backup system. Sent from my iPhone On Nov 14, 2009, at 2:40 PM, Christopher Hoover c...@murgatroid.com wrote: David I. Emery wrote: I have emailed my brother in law who is a rear admiral (I think now called a vice admiral) and currently CFO of the USCG (and as a note re your alma mater a MIT Sloan grad) and rather loudly said so myself. He most likely was part of the group that made the decision... I intend to ask him why they did it when I next see him. David, I see three possibilities: a) modernization (E-LORAN), b) maintain existing service and capabilities, c) shut it down. It would be helpful to know if USCG supports the plan to shut the system down. If USCG does not, those of us who are US citizens can lobby Congress to restore funding for the service. There's an educational piece here to do. -ch ___ 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] The Demise of LORAN (was Re: Reference oscillator accuracy)
LORAN is a good back up, but it has problems and limitations. Navigating next to a storm can overwhelm the receiver and make it unusable. The LORAN system doesn't have a build in accuracy degradation system like GPS(RAIM - receiver autonomous integrity monitoring), and this make LORAN unfit to fly Non-Vertical Guidance approaches. GPS with its accurate positioning, fast update rate and WAAS make is an awesome aircraft navigation system that can replace almost all NAVAIDS including ILS. Today with GPS, we can fly in instrument conditions from take off to landing without ever tuning any external NAVAID; not even INS can't do that. It is pretty amazing to me! -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Hal Murray Sent: Saturday, November 14, 2009 7:13 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) I've read and heard from this forum as well as a number of other sources that GPS can be easily jammed. What makes GPS so vulnerable? How can it be jammed? The signal is very very very weak. The question is not how can it be jammed, but rather how can you find the signal at all. There was a recent message here reporting on the 5th harmonic of a small 315 MHz radio link wiping out GPS for a 1/2 mile: http://www.mail-archive.com/time-nuts@febo.com/msg22033.html Here is a good story: Unjamming a Coast Harbor James R. Clynch, Andrew A. Parker, George Badger, Wilbur R. Vincent, Paul McGill, Richard W. Adler GPS World, Jan 1, 2003 http://www.gpsworld.com/gps/system-challenge/the-hunt-rfi-776 -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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: Spectrum Analyzer
I bought from Naptech a very clean HP8566B for $2200. I am very happy with it. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of John Miles Sent: Friday, October 30, 2009 11:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT: Spectrum Analyzer At Microwave Update last week, Hangar 18 Surplus ( http://www.hangar18surplus.com ) had a really clean looking, late-production Tek 497P on their table for $2500. That would be a really good match for what you're asking for. I was surprised it didn't sell -- you might call them and see if they still have it. I don't think you'll miss the 141T if you get one of these. -- john, KE5FX I'm thinking of buying a spectrum analyzer and would like to know what Time Nuts recommend. My requirements are fairly simple: 3GHz Max frequency or higher Either GPIB or Ethernet interface for control and data capture Not much larger than an average desktop computer. Portable is nice but not necessary. Preferably under $3000. I thought about building Scotty's Spectrum Analyzer or Poor Man's Spectrum Analyzer, but decided I would rather buy one then build one. I have an HP 141T but I am looking for something more modern. One of my uses will be looking at C and Ku band satellite signals (down converted to 950-2050 MHz). I'll also be using it to look at various RF data links from 433 MHz to 2.4 GHz. Thanks, Brent ___ 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. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13600 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13600 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] FS: Austron Clock Distribution Unit
Fos sale: Austron Model 1295D Series Distribution Chassis Includes: AC/DC Power Supply Qt1 - Low Loise Wideband Module Qt 3 - Quad W/B Output Manual Unit looks new, but it is untested. Price $250 plus shipping from 75044 Thanks, Francesco Ledda E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13600 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] time-nuts Digest, Vol 63, Issue 52
In the US, we use both systems. During engineering school, we mainly used the exponent system as done in Europe; we also used the US system for historycal and practical reasons. Some people here in the US feel more confortable one system and others with the other. My opinion is that as long as they are used correcly, both systems are just fine. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Florian Teply Sent: Sunday, October 11, 2009 10:40 AM To: time-nuts@febo.com Subject: Re: [time-nuts] time-nuts Digest, Vol 63, Issue 52 Am Sunday 11 October 2009 16:57:50 schrieb Arnold Tibus: On Sun, 11 Oct 2009 16:27:32 +0200, Arnold Tibus wrote: When used these numbers in calculations we anyway have to convert these ppm, ppb, ppt etc. to scientific numbers using exponents There are too often discussions and misunderstandings because the ignored case sensitivity of units (b for bit, B for Byte, m for milli, M for Mega...). Btw. I remember to all these strange mmH, µµF etc. when I collected rare inductors, capacitors revovered from vintage MIL- equipment in the end fifties/ early sixties of last century ... :-) I believe that Time Nuts prefer precise and clear expressions!? ;-) What do you think about it? waiting eagerly for the new issue of LH, regards Arnold I wanted to know where the difference of Million and Milliard and Billion is coming from. I found a good summary here http://eyeful-tower.com/muse/billion.htm Both (systems) were invented by the French, but the British and Americans do use differnt systems ... isn't it dangerous? Depts should be shiftet from UK to US - and the deposits vice versa - wouldn't it be a good deal? ;-) Arnold Just to comment on exactly that article you posted: even if the british would switch to the short scale (skipping milliard and billiard and so on), there's still the rest of europe using the long scale. From that point of view, so far only North America is on the odd side. Anyways, i'd strongly support a scientific approach using exponents. Just my 2Cents, Florian ___ 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. E-mail message checked by Spyware Doctor (6.1.0.447) Database version: 6.13450 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.1.0.447) Database version: 6.13450 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] 4046 variations (was EPE GPS....)
The only portion of the device with possibly significant variability is the VCO. If the design does not take care of the VCO variability, for the capture range of the PLL; things may not work. If the device had a Phase-Frequency detector, instead of a phase detector, the capture range would not be a problem. Phase detectors are OK, when an acquisition aid is available or when the PLL closed loop BW is much larger than the max phase rate a start up. I am surprised to hear that such kind of sloppy design was allowed to be released. When I worked at Rockwell-Collins, such thing would have been a big No-No! Regards, Francesco -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Javier Herrero Sent: Sunday, September 27, 2009 9:23 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 4046 variations (was EPE GPS) Margina design? ;) Better said, very poor design. Does not sound very good that same part, same lot code, sometimes work here but not there, sometimes does not work at all... Extending it a bit... sometimes will work at a given temperature, sometimes will not at a given other. Regards, Javier Robert Atkinson escribió: The old King Radio (then Bendix-King now part of Honeywell) Silver crown aircraft radios used 4046's in some of the synthesisers. The one in the VHF com had a different King part number to that in the ADF (MF direction finder). While trouble shooting we tried an ADF chip in a VHF (didn't have the VHF part in stock). It sort of worked but was slow to lock-up at the ends of the frequency range. Ordered some of the correct parts, both ADF and VHF. They all had the same manufacturer's part number and date code but different King numbers overstamped. Appaently the selected then at the factory for low noise (ADF) or wide pull-in (VHF). Robert G8RPI. --- On Sun, 27/9/09, Joe McElvenney xi...@btinternet.com wrote: From: Joe McElvenney xi...@btinternet.com Subject: [time-nuts] Egg on Face (was EPE - GPS Frequency Reference Project) To: Time Nuts Digest time-nuts@febo.com Date: Sunday, 27 September, 2009, 11:00 AM Hi, There's a subtle difference between 3rd phase detectors in the 74HC4046A (Philips/NXP, ON, TI) and the 74HC4046 (Fairchild, NS) The 3rd Phase detector in the 74HC4046A works as the designer intended in the GPSDO circuit, the 3rd phase detector in the 74HC4046 does not. The 74HC4046 uses an RS flipflop for the 3rd phase detector and requires narrow pulses on the R and S inputs. The 74HC4046A uses extra internal gates to ensure that only narrow pulses are seen by the RS flipflop in the 3rd phase detector. Bruce You are perfectly correct. I hadn't noticed that there was a 74HC4046A fitted to the board in the article but just a plain 74HC4046 shown in the parts list. However, it is something to watch out for as this will be a popular project among those, like myself, who do not need to slice time quite so finely. Cheers - Joe G3LLV ___ 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. -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17AFAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ 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. E-mail message checked by Spyware Doctor (6.1.0.447) Database version: 6.13350 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.1.0.447) Database version: 6.13350 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] Lady Heather's Source Code
Hi, Where can I download the source code? Thank you! E-mail message checked by Spyware Doctor (6.1.0.447) Database version: 6.13350 http://www.pctools.com/en/spyware-doctor-antivirus/ ___ 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] HP 8753A on ExxY - good price
Tittle says it all. ___ 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] Correction: HP 5373A on ExxY - good price
Sorry, it is a 5373A!It is not mine. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Francesco Ledda Sent: Wednesday, September 09, 2009 10:50 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] HP 8753A on ExxY - good price Tittle says it all. ___ 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 5372a error 160
You need to replace the internal battery (3.6) and calibrate the inputs; the procedure is simple. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Norman J McSweyn Sent: Friday, September 04, 2009 8:16 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] HP 5372a error 160 Hi all!! Bid on and got an HP 5372a. Supposed to be tested, working. Powers up to error 160 out of sensitivity calibration. Did download the svc man from Agilent. Spent a few minutes looking through the manual. Not sure what to make of it. It's not obvious whether a complete cal needs to be done. Questions, comments cheerfully received. Will be on a boat trip for our holiday (US) from 10z Saturday until Tuesday 10z or so. Thanks, Norm n3ykf ___ 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 5372a error 160
It is easy to do. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Norman J McSweyn Sent: Friday, September 04, 2009 8:53 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 5372a error 160 Francesco, I saw in the troubleshooting section that a weak internal battery could be the cause. HA!!! Just found the procedure in the manual!! Looks deceptively easy. Thanks, Norm n3ykf Francesco Ledda wrote: You need to replace the internal battery (3.6) and calibrate the inputs; the procedure is simple. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Norman J McSweyn Sent: Friday, September 04, 2009 8:16 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] HP 5372a error 160 Hi all!! Bid on and got an HP 5372a. Supposed to be tested, working. Powers up to error 160 out of sensitivity calibration. Did download the svc man from Agilent. Spent a few minutes looking through the manual. Not sure what to make of it. It's not obvious whether a complete cal needs to be done. Questions, comments cheerfully received. Will be on a boat trip for our holiday (US) from 10z Saturday until Tuesday 10z or so. Thanks, Norm n3ykf ___ 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 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] Wireless Adapter for an TBolt
you could use remote desktop -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of brucekar...@aol.com Sent: Friday, July 03, 2009 8:50 AM To: time-nuts@febo.com Subject: [time-nuts] Wireless Adapter for an TBolt Has anyone coupled a wireless adapter to a TBolt so that it can be accessed from a computer in another room. This would be convenient for me if it could be made to work. Bruce Hunter **It's raining cats and dogs -- Come to PawNation, a place where pets rule! (http://www.pawnation.com/?ncid=emlcntnew0008) ___ 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] Bad capacitors (was Volt-nuts cooperation?)
I believe you. You know that its is better to be lucky than smart ;) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Mark Sims Sent: Sunday, June 21, 2009 11:22 AM To: time-nuts@febo.com Subject: [time-nuts] Bad capacitors (was Volt-nuts cooperation?) The problems I saw were mostly hard failures in the caps (opens/shorts/etc). These were in both power caps and signal caps. One lot that I saw was a group of 12 Mettler scales. 6 were used daily and 6 were never used backup units. When the company shut down the operations that used the scales, they were sold. All the used units worked fine. The backup units all had capacitor problems. I also bought a lot of new-in-box Tektronix TM500 modules. Most wound up having flakey capacitors. BTW, EVERY (new or used) Tek PG505 pulse generator you will come across will have bad power supply filter caps... unless they were replaced. Does this happen even if the electrolytics are reformed before use? _ Lauren found her dream laptop. Find the PC that’s right for you. http://www.microsoft.com/windows/choosepc/?ocid=ftp_val_wl_290 ___ 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] Volt-nuts cooperation?
Lucky me, I bought an HP3455A new still in the box for $300! -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Mark Sims Sent: Saturday, June 20, 2009 5:05 PM To: time-nuts@febo.com Subject: [time-nuts] Volt-nuts cooperation? The 3458A has two types of calibrations. The first is done every year or two using the external references. The other is an internal self calibration which you should run every day or two. This is pretty much standard for every high res meter on the market today (except most want you to send it to the external cal lab every six months) The 3458A is probably the best meter on the market. It seems like multimeters pretty much stopped evolving with this unit. Basically 8.5 digits seems to be the practical limit of resolution that you can extract from silicon devices. 8.5 digit meters have been available for around over 20 years now. Nobody seems to have come out with anything better in the last 20+ years. As far as spending $4-5K for a 3458A, if you are patient and a little lucky you can score one for half that. I bought one for under $1500 (but sold it after I was made an offer I could not refuse). My latest one cost $2500. There is one on Ebay right now that opens at $1600. I suspect it will sell for under $2800. I am a little confused as to your needs. On the one hand you feel the hp3458A is a fine instrument only needing “CAL” every 2 years, yet you then say it needed to be “CAL’d” every 2 days to stay repeatable. That does not sound very encouraging and is indicative of other problems. _ Hotmail® has ever-growing storage! Don’t worry about storage limits. http://windowslive.com/Tutorial/Hotmail/Storage?ocid=TXT_TAGLM_WL_HM_Tutoria l_Storage_062009 ___ 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] Z3805 initial behavior after power up revised
Variation due to environment are deterministic and are nor part of aging. Ageing needs to measured in conditions that remove ambient induced perturbations. I used to put crystal oscillators in high quality environmental chambers that kept temp, humidity and pressure constant and measure the ageing. There are tricks that can be done to increase the aging rate, so that we did not have to wait 20 years ;) We know that ageing happens, but the direction of ageing cannot be determined. A coin toss can yield face or tail. If the coin is perfect, the distribution will be uniform. If a face is 1 and a tail is -1, we can add successive tosses and track the total number. Even is the distribution of tosses is uniform, the sum will walk away from 0 (random walk),cameback to 0 and then move away from 0 again. This is a good way to model and explain ageing. Nature is perfect, but things do not follow our math perfectly. A better simulation would include a leaky integral. The statistical analysis of ageing is tricky, since ageing doeas have a statistical mean, and therefore standard deviation cannot be used. This discussion brings lots of good memories back. The good old days when SONET synchronization was a new thing, and we were creating new technology. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Magnus Danielson Sent: Friday, June 19, 2009 7:59 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Z3805 initial behaviour after power up revised Francesco Ledda wrote: Aging cannot be predicted! If it could be predicetd, there would be no aging. Not entierly true. Even with a perfectly known aging, only a few oscillators would bother to estimate and correct it. This can never be perfectly done anyway, and there is only so many things you can bring into the model while keeping it economical. There is fairly good clues around. If all was included and handled, it would reduce the effects. Cheers, Magnus -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Ulrich Bangert Sent: Thursday, June 18, 2009 3:04 AM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] Z3805 initial behaviour after power up revised Gents, one of the papers suggested by Brian says: --- SmartClock monitors the frequency control variable of the internal oscillator while it is locked to the external reference. This gives a measure of the frequency difference between the internal oscillator, if it is free-running, and the external reference over time. The resulting measurements include the effects of random noise in the oscillator, the measurement circuitry, and any noise in the external reference as well as any aging and environmental effects in the oscillator. From this information, SmartClock makes a continuous prediction of clock error over time. --- The big question is: If the EFC signal includes this all information, how does the algo manage to extract the individual informations? After having a look at the PPS TI and the EFC of my Z3805 I am beginning to get a clue of it (the quirks on the EFC signal heve been removed): The SmartClock algo seems to set the loop time constants to a large value in the beginning. In other words: It measures the overall oscillator frequency influencing effects with a lowpass filter applied that has a very low cutoff frequency. Only effects which's frequency are sufficient lower then the cutoff pass the filter. Seems as if the SmartClock uses this filter setting to exclude any noise related effect and any environmental effect and make the measurement see ONLY the oscillator's aging. Once it has learned enough about the aging process it will be able to predict aging. Having reached this state it will be able to apply his knowledge about aging to further TI measurements and subtract the aging part of it, leaving mostly the environmental (which is mostly temperature) part. Having a model for the aging the Algo can now model the temperature dependence. However, a precondition for this were that the measurement sees the temperature effects and that the ambient temperature is measured independently. For that reason I expect the Algo will reduce its loop time constant within the next time to make the temperature effect get through the lowpass. Any bets on that? Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Ulrich Bangert Gesendet: Donnerstag, 18. Juni 2009 08:29 An: 'Discussion of precise time and frequency measurement' Betreff: Re: [time-nuts] Z3805 initial behaviour after power up Brian, You may also want to search for HP An1279, it also goes over HP smartclock operation, and look
Re: [time-nuts] Z3805 initial behaviour after power up revised
Aging cannot be predicted! If it could be predicetd, there would be no aging. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Ulrich Bangert Sent: Thursday, June 18, 2009 3:04 AM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] Z3805 initial behaviour after power up revised Gents, one of the papers suggested by Brian says: --- SmartClock monitors the frequency control variable of the internal oscillator while it is locked to the external reference. This gives a measure of the frequency difference between the internal oscillator, if it is free-running, and the external reference over time. The resulting measurements include the effects of random noise in the oscillator, the measurement circuitry, and any noise in the external reference as well as any aging and environmental effects in the oscillator. From this information, SmartClock makes a continuous prediction of clock error over time. --- The big question is: If the EFC signal includes this all information, how does the algo manage to extract the individual informations? After having a look at the PPS TI and the EFC of my Z3805 I am beginning to get a clue of it (the quirks on the EFC signal heve been removed): The SmartClock algo seems to set the loop time constants to a large value in the beginning. In other words: It measures the overall oscillator frequency influencing effects with a lowpass filter applied that has a very low cutoff frequency. Only effects which's frequency are sufficient lower then the cutoff pass the filter. Seems as if the SmartClock uses this filter setting to exclude any noise related effect and any environmental effect and make the measurement see ONLY the oscillator's aging. Once it has learned enough about the aging process it will be able to predict aging. Having reached this state it will be able to apply his knowledge about aging to further TI measurements and subtract the aging part of it, leaving mostly the environmental (which is mostly temperature) part. Having a model for the aging the Algo can now model the temperature dependence. However, a precondition for this were that the measurement sees the temperature effects and that the ambient temperature is measured independently. For that reason I expect the Algo will reduce its loop time constant within the next time to make the temperature effect get through the lowpass. Any bets on that? Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Ulrich Bangert Gesendet: Donnerstag, 18. Juni 2009 08:29 An: 'Discussion of precise time and frequency measurement' Betreff: Re: [time-nuts] Z3805 initial behaviour after power up Brian, You may also want to search for HP An1279, it also goes over HP smartclock operation, and look for a paper titled the Global Positioning System and HP SmartClock by John A. Kusters. In the meantime I have not only found these but also Smart Clock: A New Time by David Allan et al which shows that Smart Clock is originally a NIST invention patent and explains very well how it works. Perhaps what I and You have seen is a direct consequence of applying the Smart Clock algorithm. Best regards Ulrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Brian Kirby Gesendet: Donnerstag, 18. Juni 2009 01:51 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] Z3805 initial behaviour after power up They do not talk about driving the frequency off, but they warn to keep the receiver locked the first 24 hours, so it can determine how the oscillator ages. Its in the section on holdover (page 52 of the PDF , page 3-8 of the user guide). You may also want to search for HP An1279, it also goes over HP smartclock operation, and look for a paper titled the Global Positioning System and HP SmartClock by John A. Kusters. If you have a broadband connection, I can email you each one, if that will help. Brian Ulrich Bangert wrote: Brian, thanks for your information! algorithm. From what I read about the smart clock, it takes 5 days for it to complete its initial learning cycle and then its continuously refining. Is that from the Z3801 manual, which I have available, or do you have any other in depth information source? Best regards Ulrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Brian Kirby Gesendet: Mittwoch, 17. Juni 2009 16:58 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] Z3805 initial behaviour after power up Ulrich, I
Re: [time-nuts] Z3805 initial behaviour after power up
A third order PPL has better sideband suppression. The tracking capability depends upon the phase range of the phase detector. If 1:1 phase comparison and a XOR phase detector is used, the range is 180 degrees. Dividers on the feedback portion of the PLL increase the phase range of the phase detector. For example, if the expected jitter is 10UI, a divider larger than 10 must be used, to maintain lock under all conditions. A monotonically decreasing phase delta, on the phase detector, still means that the PLL is locked. The phase/frequency detector, avoids the need for a frequency aquisition aid. Once a phase reversal is detected by the flip flops in the phase/freq detector, it goes back to phase detector mode. My experience is that most fancy syncrhonizer for telecom application (Stratum, LORAN and GPS) use start-stop phase detector with averager in front of the AC-DC gain circuits. Changing the closed loop bandwidth of the PLL on the fly is not easy, due to secondary effects (done that many times). -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Magnus Danielson Sent: Wednesday, June 17, 2009 2:31 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Z3805 initial behaviour after power up Hi Brian, Brian Kirby skrev: Ulrich, I have two Z3801A and both of them act close to what you describe in the first 24 hours of power up. I believe its part of the disciplining algorithm. From what I read about the smart clock, it takes 5 days for it to complete its initial learning cycle and then its continuously refining. For me it sounds more like a design-flaw than anything else. Using several PLL bandwidths and switch between them is as such a good approach, but the stepping between then needs to be done such that a narrower bandwidth is only chosen when it the lock-in can be maintained. Similarly, backing out of a narrow step to a wider step should also be detected at suitable levels when it can't maintain track. The phase detector gives hints about the ability to maintain track, as the phase will deviate uncontrollably when loosing lock, but before that happens it will deviate from near +/- 0 degrees, similarly, when within near +/- 0 degrees for sufficient time it is reasnoble that the next step (if not too big) can maintain track. Recall that sufficient time changes with the bandwidth of the PLL. A third degree (PII^2 or PII^2D) PLL is better able to cope with drift rate than a second degree PLL. A combined phase/frequency detection approach (I.e. add the D term) adds quicker response to drift and ability to keep tracking. Another approach is to use a Kalman filter, where the Kalman gain is adapted continuously. Kalman filters takes some careful thought, it's not a magical wand to wave to make things better by magic. If done properly, it will be able to fairly well track along and detect the drift rate (takes a phase/frequency/drift model to handle) and update as it stabilizes. None of these approaches is rocket science to design anymore. HP/Agilent surely could at the time of Z3801A and followers. 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 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] Request for manuals for HP 5372A
try http://www.mkdw.net/pub/radio/hp/Manuals/?C=N;O=D The manual is 05372-90016.pdf -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of gandal...@aol.com Sent: Friday, June 05, 2009 6:55 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Request for manuals for HP 5372A In a message dated 05/06/2009 11:50:58 GMT Daylight Time, sar10...@gmail.com writes: Does anyone have any links to the documentation for the HP 5372A please? I have the programming manual from the Agilent site but the is no Ops/Service manuals and I'm sure there must be tons of stuff for this very versatile instrument. Thanks 73, Steve -- They're all on the Agilent web site... _http://www.home.agilent.com/_ (http://www.home.agilent.com/) Just enter 5372A in the search box and select Electronic Test and Measurement in the drop down box next to that. regards Nigel GM8PZR ___ 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] Request for manuals for HP 5372A
I used the 5372 for years to design and test SONET synchronizers. I had option 40 istalled but never used it. I always downconverted my test clock to 1 kHz or lower to increase the resolution of the counter. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of aceamuseme...@mchsi.com Sent: Friday, June 05, 2009 9:57 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Request for manuals for HP 5372A Hi, I also have several of these but none have the 2 ghz option C installed I was wondering if anybody out there would happen to have any option C avail or a unit for parts with option C? or possibly know where one could purchase the card and input plug without buying another complete unit?? -- Original message from gandal...@aol.com: -- In a message dated 05/06/2009 11:50:58 GMT Daylight Time, sar10...@gmail.com writes: Does anyone have any links to the documentation for the HP 5372A please? I have the programming manual from the Agilent site but the is no Ops/Service manuals and I'm sure there must be tons of stuff for this very versatile instrument. Thanks 73, Steve -- They're all on the Agilent web site... _http://www.home.agilent.com/_ (http://www.home.agilent.com/) Just enter 5372A in the search box and select Electronic Test and Measurement in the drop down box next to that. regards Nigel GM8PZR ___ 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] 747 Chronometer
Most likely, the clock needs 5V for the internal lighting. Many aircrft clocks are mechanical, but some are lectrical and need 28VDC. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Charles Rushing Sent: Thursday, May 21, 2009 1:45 AM To: time-nuts@febo.com Subject: [time-nuts] 747 Chronometer Greetings To All, Please accept my apologies in advance if this is off-topic. I have just acquired an aircraft clock, which I've tentatively identified as coming from a Boeing 747. It's way cool looking and would make a perfect dust collector in my ham shack if I could only power it up. There is a multi-pin military-style twist-lock connector on the back, but no indication of what the pinout may be. The unit is identified as: CLOCK, 3 24 HOUR GMT ELECTRONIC MFD BY A.W. HAYDON CO. PRODUCTS NO. AMER. PHILIPS CONTROLS CORP. Cheshire, Conn. MFR'S. PT. NO. A15551-P1 I've searched the Net for technical documentation, but could only find the reference to the 747. Does anyone have any information about these clocks, or can someone point me in the right direction? Many thanks in advance. Chuck WA5MUV ___ 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] Home made GPS disciplined atomic clock
The challenge is to detect a failure of the GPS source (LOS) before the DPLL moves the OCXO. I used to design Stratum clocks for a large telecom company, and I used several trick do detect a phase ramp on the digital phase detector; this was used to declare a probable bad source. At that point, we halted the movement of the DPLL and observed the phase detector activity. We had two DPLLs, and if both detected a phase ramp, we declared the source bad. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Tom Van Baak Sent: Sunday, January 25, 2009 11:03 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Home made GPS disciplined atomic clock I think that it should be a much better (in theory) than OCXO which comes short therm stability (what I'm actually seeking for). It should be much more accurate with long holdovers also. Right, it all depends on what stability you're after. The OCXO will have much better short-term stability than the LPRO -- the LPRO is close to ten times worse. So do not replace the TBolt OCXO with a LPRO if short-term stability is your goal. See: TBolt OCXO plots: http://www.leapsecond.com/pages/gpsdo/ http://www.leapsecond.com/pages/tbolt-tc/ LPRO plots: http://www.leapsecond.com/museum/lpro/ However, if long-term, GPS-unlocked, holdover performance is the goal, then using a Rb would make a good choice. This is very simple modification by the way. Infact my original plan was to use the 1PPS to synchronize the LPRO C-field with separate control ... See John Miles work to replace the Thunderbolt OCXO: http://www.thegleam.com/ke5fx/tbolt.htm /tvb Here's a link for the log: http://www.amigazone.fi/files/gpsdo/tbolt-lpro-test.log (Log format: TOW, PPS offset, DAC voltage, Disciplining mode activity) I'll have a look at this; but it's not accessible for some reason. /tvb ___ 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] Home made GPS disciplined atomic clock
There are techniques to remove/eliminate the phase error when the GPS source comes back on line. If the holdover is entered appropriately, the frequency error should be small and dependent on the stability of the OCXO. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Bruce Griffiths Sent: Sunday, January 25, 2009 1:01 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Home made GPS disciplined atomic clock ewkeh...@aol.com wrote: Its main purpose was time synchronization. Bert Bert But time and frequency are dual aspects of the same phenomenon. The only real concern is the behaviour of the Thunderbolt when recovering from holdover. There will be transient time (phase ) and frequency excursions. One can either allow a jam sync for fast correction of any accumulated time error or disable it and accept the potentially larger frequency excursions as the disciplining loop locks the PPS output to GPS time. Performance during holdover depends on whether the Kalman filter has accumulated sufficient information to correct for drift tempco and other predictable errors during holdover. 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.
[time-nuts] Set Up instructions: FE-5440A O-1824A/U
I am looking for a manual for the FEI FE-5440A O-1824A/U cesium source. I also need the instrument power up/set up instructions. Thank you in advance! Regards, Francesco Garland, Texsa ___ 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.
