Re: [time-nuts] Possibly OT: Maintenance manual for Racal 1998 and 1999 now a...
In a message dated 09/09/2010 02:34:59 GMT Daylight Time, eb4...@cembreros.jazztel.es writes: Thank you very much for your efforts. And BTW, any PTS 040 manual around? - Hi Ignacio I presume you've found the PTS160, PTS310, etc manuals on Didier's site? I've not seen a manual for the PTS040 but it might be worth checking your unit against these other manuals as there's several at least of the PTS synthesisers that share a similar circuit arrangement and also have some identical modules. 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.
Re: [time-nuts] OT: Christchurch NZ Quake Map
Brings back memories- I was on the west coast of the south island in 1990, leaning against a large log on the beach very close to the water line at sunset, when a quake hit. Being from California, it was fun because I was used to experiencing quakes in buildings, cars, etc; but I had never felt one in such a natural setting. Kind of hard to explain, but it was a very other-worldly experience. -Dave - Original Message - From: Steve Rooke sar10...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, September 8, 2010 6:16:45 PM Subject: [time-nuts] OT: Christchurch NZ Quake Map Sorry this is a bit OT but various people have shown interest in what is happening over here so you might like to look at this animated map showing the progress of the quakes in chronological order. This was designed and produced by Paul Nicholls of the University of Canterbury, Christchurch, New Zealand. http://www.christchurchquakemap.co.nz/ Steve -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ 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] Possibly OT: Maintenance manual for Racal 1998 and1999 now available for download
EADS is a bit more than test equipment. see http://www.eads.com/eads/int/en.html#/story-2 Robert G8RPI. --- On Thu, 9/9/10, David C. Partridge david.partri...@perdrix.co.uk wrote: From: David C. Partridge david.partri...@perdrix.co.uk Subject: Re: [time-nuts] Possibly OT: Maintenance manual for Racal 1998 and1999 now available for download To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Date: Thursday, 9 September, 2010, 10:21 Quoting from their website home page: EADS Test Services (UK) Limited is located near the south coast at Ferndown in Dorset and was formed following the acquisition of the Racal Instruments Group of companies The do some interesting stuff for time nuts too! http://www.eads-ts.com/index.php?url=Products/Instruments/index.php Though your pockets may not be deep enough ... Regards, David Partridge -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bill Hawkins Sent: 09 September 2010 08:24 To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Possibly OT: Maintenance manual for Racal 1998 and1999 now available for download Many, many, many thanks for your research, David. Who is EADS? ___ 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] slightly OT: EADS/Racal 1991 opt 55M
On 9/9/2010 7:03 AM, p...@pseng.org.uk wrote: I'll second the thanks to EADS (and David). I too used too look for support for older equipment when buying for day job. Currently struggling with opt55M ie the miltary coding CIL/MATE etc for a stack of 6 1991's for TI use. Any pointers on using CIL/MATE would be much appreciated. Phil, I'm pretty sure there's a link that you can move inside to convert these to standard gpib, at least in the 1992 there was. This was covered in the past here I think. Have you checked the archives? 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.
[time-nuts] Timing Distribution in Mountainous Terrain
We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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] Timing Distribution in Mountainous Terrain
Symmetricom makes GPS based NTP time servers with excellent holdover capability. I think our SyncServer with an OXCO is good for +/- 0.5 second holdover over something like 60 days. They have options for Rb oscillators installed that will make that much much better and it might fall inside of your requirements. Give them a look. You're welcome to mail me directly with questions about mine if you like. -Bob On Thu, Sep 9, 2010 at 9:37 AM, Ralph Smith ra...@ralphsmith.org wrote: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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] Timing Distribution in Mountainous Terrain
How widely spread is your network? Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Ralph Smith ra...@ralphsmith.org Sender: time-nuts-boun...@febo.com Date: Thu, 9 Sep 2010 11:37:46 To: time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] Timing Distribution in Mountainous Terrain We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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] watch innards video
Hi FL: Thanks for the link to the book on escapements. Maybe it contains an explanation for the Self Winding Clock escapement: http://www.prc68.com/I/SWCC.shtml#Esc Have Fun, Brooke Clarke http://www.PRC68.com Flemming Larsen wrote: When I was a kid, I loved to watch the pendulum swing back and forth and listen to the tick-tock of my grandparents old wall clock. When I was about five, I completely disassembled my parent's mantle clock. It wasn't until many years later that I learned to put them back together and learn about what makes them work. For an interesting document about clock and watch escapements, check this out: http://www.angelfire.com/ut/horology/EscMechanics.pdf For endless hours of entertainment, watch the animated drawings on this website: http://www.angelfire.com/ut/horology/escapement.html -- FL --- Den ons 8/9/10 skrev normn3...@stny.rr.comnormn3...@stny.rr.com: Fra: normn3...@stny.rr.comnormn3...@stny.rr.com Emne: Re: [time-nuts] watch innards video Til: Discussion of precise time and frequency measurementtime-nuts@febo.com Dato: onsdag 8. september 2010 08.45 http://www.youtube.com/watch?v=OiCPu0SjEW4 OHH!!! If I didn't find electronics so fascinating, I'd be going to school for an ME degree rather than an EE.. David Smithw...@msn.com wrote: Norm, the link was stripped out of your message. Please send it to me directly. Thanks, Dave W6TE Date: Wed, 8 Sep 2010 10:32:52 -0400 From: normn3...@stny.rr.com To: time-nuts@febo.com Subject: [time-nuts] watch innards video Hi all!! If you don't know a mainspring from an escapement, watch this video. I was wondering about the physics of the hairspring, jewel pin and escapement/pallete arm. Cool stuff. 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. -- Have Fun, Brooke Clarke http://www.PRC68.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.
Re: [time-nuts] Timing Distribution in Mountainous Terrain
The requirement is 30 nanoseconds, so individual rubidium holdover over six days won't cut it. Ralph On Thu, September 9, 2010 11:58 am, Robert Darlington wrote: Symmetricom makes GPS based NTP time servers with excellent holdover capability. I think our SyncServer with an OXCO is good for +/- 0.5 second holdover over something like 60 days. They have options for Rb oscillators installed that will make that much much better and it might fall inside of your requirements. Give them a look. You're welcome to mail me directly with questions about mine if you like. -Bob On Thu, Sep 9, 2010 at 9:37 AM, Ralph Smith ra...@ralphsmith.org wrote: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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] Timing Distribution in Mountainous Terrain
The network is spread over about 250-300 US miles. Ralph On Thu, September 9, 2010 12:01 pm, Didier Juges wrote: How widely spread is your network? Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Ralph Smith ra...@ralphsmith.org Sender: time-nuts-boun...@febo.com Date: Thu, 9 Sep 2010 11:37:46 To: time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] Timing Distribution in Mountainous Terrain We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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] Timing Distribution in Mountainous Terrain
On 9/9/2010 8:37 AM, Ralph Smith wrote: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. 30 ns seems a little closer than most radio site applications need... what drives this requirement? Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. Wow, ok, and what drives *that* requirement? Can you use any other mutually visible thing, or do we assume all satellites have vanished from orbit? Matthew Kaufman ___ 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] Timing Distribution in Mountainous Terrain
Does the GPS backup include other sats ? As long as all sites could see the same sat then using it as a standard they would drift together. Stanley - Original Message From: Ralph Smith ra...@ralphsmith.org To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 9, 2010 11:45:04 AM Subject: Re: [time-nuts] Timing Distribution in Mountainous Terrain The requirement is 30 nanoseconds, so individual rubidium holdover over six days won't cut it. Ralph On Thu, September 9, 2010 11:58 am, Robert Darlington wrote: Symmetricom makes GPS based NTP time servers with excellent holdover capability. I think our SyncServer with an OXCO is good for +/- 0.5 second holdover over something like 60 days. They have options for Rb oscillators installed that will make that much much better and it might fall inside of your requirements. Give them a look. You're welcome to mail me directly with questions about mine if you like. -Bob On Thu, Sep 9, 2010 at 9:37 AM, Ralph Smith ra...@ralphsmith.org wrote: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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] Timing Distribution in Mountainous Terrain
If you need that kind of timing accuracy in the absence of GPS then Cs is probably the only answer. Dark fiber would also work but the infrastructure and fiber leasing costs would probably be much more expensive than local Cs Sent from my Verizon Wireless BlackBerry -Original Message- From: Ralph Smith ra...@ralphsmith.org Sender: time-nuts-boun...@febo.com Date: Thu, 9 Sep 2010 12:48:54 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Timing Distribution in Mountainous Terrain The network is spread over about 250-300 US miles. Ralph On Thu, September 9, 2010 12:01 pm, Didier Juges wrote: How widely spread is your network? Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Ralph Smith ra...@ralphsmith.org Sender: time-nuts-boun...@febo.com Date: Thu, 9 Sep 2010 11:37:46 To: time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] Timing Distribution in Mountainous Terrain We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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] Timing Distribution in Mountainous Terrain
On Thu, September 9, 2010 1:10 pm, Matthew Kaufman wrote: On 9/9/2010 8:37 AM, Ralph Smith wrote: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. 30 ns seems a little closer than most radio site applications need... what drives this requirement? Aircraft surveillance using multilateration. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. Wow, ok, and what drives *that* requirement? Can you use any other Paranoia. People making the requirements are concerned with GPS going away due to solar flare or some other reason. mutually visible thing, or do we assume all satellites have vanished from orbit? No satellites. Thanks, Ralph ___ 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] Timing Distribution in Mountainous Terrain
Ralph-- As far as getting a signal through mountainous terrain, look at NVIS antennas for HF -- we use them for Field Day for just that kind of communications, 200 - 300 miles in mountainous terrain. Figuring out propagation delays is going to be interesting with NVIS though. 73 de Bob K6RTM -- Message: 3 Date: Thu, 9 Sep 2010 11:37:46 -0400 From: Ralph Smith ra...@ralphsmith.org Subject: [time-nuts] Timing Distribution in Mountainous Terrain To: time-nuts@febo.com Message-ID: a3fa9eac817be681f75c1df76ba2adf5.squir...@ralphsmith.org Content-Type: text/plain;charset=iso-8859-1 We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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] Timing Distribution in Mountainous Terrain
On 9/9/2010 10:42 AM, Ralph Smith wrote: On Thu, September 9, 2010 1:10 pm, Matthew Kaufman wrote: On 9/9/2010 8:37 AM, Ralph Smith wrote: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. 30 ns seems a little closer than most radio site applications need... what drives this requirement? Aircraft surveillance using multilateration. So timing errors just become position errors. How do the sites talk back to the display? Can't you null out position errors if enough sites can see a single plane, and thus learn the timing error of the drifting (relative to other) site? Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. Wow, ok, and what drives *that* requirement? Can you use any other Paranoia. People making the requirements are concerned with GPS going away due to solar flare or some other reason. Once everyone relies on GPS approaches and ADS-B, the planes will be grounded long before 6 whole days of GPS outage anyway. mutually visible thing, or do we assume all satellites have vanished from orbit? No satellites. Ok then. My best answer is to use the planes themselves as the common reference, at least the ones high enough that enough sites can see them. Also consider that you might be able to find additional mountaintop sites to plant fixed squitter-emitter transponders at that can be seen by 2 (or more) sites. Matthew Kaufman ___ 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] Timing Distribution in Mountainous Terrain
What about Symmetricom XPRO Rubidium? It says on the data sheet they have a low aging rate option (1e-11 / month). ___ 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] Possibly OT: Maintenance manual for Racal 1998 and 1999 now a...
Nigel, Yes, I have downloaded them for the PTS 160, 500, 3200 and X10 and you are correct, all those synthesizers share the same basic principles and maybe some modules, but I found that the frequencies involved are not the same. The problem with mine is that it shows frequency errors at some settings and when it happens the generated signal shows bad spectral purity. Maybe a module went mistuned due to a component aging or failure and having the right manual while is not a must it would be very helpfull. Regards Ignacio, EB4APL gandal...@aol.com wrote: In a message dated 09/09/2010 02:34:59 GMT Daylight Time, eb4...@cembreros.jazztel.es writes: Thank you very much for your efforts. And BTW, any PTS 040 manual around? - Hi Ignacio I presume you've found the PTS160, PTS310, etc manuals on Didier's site? I've not seen a manual for the PTS040 but it might be worth checking your unit against these other manuals as there's several at least of the PTS synthesisers that share a similar circuit arrangement and also have some identical modules. 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] Timing Distribution in Mountainous Terrain
On Sep 9, 2010, at 10:42, Ralph Smith ra...@ralphsmith.org wrote: Paranoia. People making the requirements are concerned with GPS going away due to solar flare or some other reason. Hmm... So the decision makers think that after a solar flare or some other reason (hostile destruction of the birds, perhaps?) takes out the GPS system, it'll be back up and running within six days? That sounds optimistic to me. It sounds to me more like you would need to function indefinitely without GPS, and just use GPS for initial position survey and as a convenient way to synchronize to external time reference (with ground-based backup methods in place and periodically tested). ___ 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] Timing Distribution in Mountainous Terrain
On Thu, September 9, 2010 1:55 pm, Matthew Kaufman wrote: On 9/9/2010 10:42 AM, Ralph Smith wrote: On Thu, September 9, 2010 1:10 pm, Matthew Kaufman wrote: On 9/9/2010 8:37 AM, Ralph Smith wrote: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. 30 ns seems a little closer than most radio site applications need... what drives this requirement? Aircraft surveillance using multilateration. So timing errors just become position errors. How do the sites talk back to the display? Can't you null out position errors if enough sites can see a single plane, and thus learn the timing error of the drifting (relative to other) site? Sites communicate via landline telco. If there are sufficient mutually visible networked sites to form a solution on an aircraft visible to stations not in the timing network that would work, and is one of the options we are studying. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. Wow, ok, and what drives *that* requirement? Can you use any other Paranoia. People making the requirements are concerned with GPS going away due to solar flare or some other reason. Once everyone relies on GPS approaches and ADS-B, the planes will be grounded long before 6 whole days of GPS outage anyway. You're making the mistake of applying logic. ;) Actually, aircraft can continue to fly VFR or navigate using VOR/DME and inertial navigation. The radios are part of an ADS-B installation. mutually visible thing, or do we assume all satellites have vanished from orbit? No satellites. Ok then. My best answer is to use the planes themselves as the common reference, at least the ones high enough that enough sites can see them. Also consider that you might be able to find additional mountaintop sites to plant fixed squitter-emitter transponders at that can be seen by 2 (or more) sites. Thanks, all of these are various options we are considering, considering all of the engineering trade-offs. Ralph ___ 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] Timing Distribution in Mountainous Terrain
1e-11 only buys you 3000 seconds of drift before blowing the 30 ns budget. Without going to cesium we will most likely need some form of mutually visible synchronization. Ralph On Thu, September 9, 2010 2:01 pm, Jason Rabel wrote: What about Symmetricom XPRO Rubidium? It says on the data sheet they have a low aging rate option (1e-11 / month). ___ 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] Timing Distribution in Mountainous Terrain
On 9/9/2010 11:57 AM, Ralph Smith wrote: You're making the mistake of applying logic. ;) Actually, aircraft can continue to fly VFR or navigate using VOR/DME and inertial navigation. The radios are part of an ADS-B installation. Yes, and they can make routine position reports and ATC can apply time-based sequencing for IFR traffic... see all sorts of past solutions to this problem. VFR aircraft don't need anyone to know where they are anyway, and IFR only need it if they're being provided radar (or equivalent) separation services. Things would work just fine after a period of adjustment, and during that period of adjustment the planes that need this kind of position determination would be grounded. I run GPS-disciplined oscillators at mountaintop radio sites *and* am a pilot, so this thread is particularly interesting to me. Matthew Kaufman ___ 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] Timing Distribution in Mountainous Terrain
Hmmm...I design such timing systems for Moto data radios, and 30nS sync is going to be very hard to achieve in reality. Over a few hundred miles you're going to have OTA time of flight issues, temperature dependencies, etc. Over the years this has been tried, usually with dismal success in the reliability department. You might get the system working in the summer, and then when winter hits and snow builds up on the GPS antennas your network goes down. Or, spring hit with a lot of atmospheric turbulance and you get all sorts of reflection / refraction effects, and trying to sync up time slots that close will be almost impossible. It might work oneweek, and not the next. What's your carrier freq? In mountainous regions you'll probably have better luck at the lower end. Please tell me you're not trying this at GHz freqs at higher, rocky elevations. You might find +-1uSec is a good number to shoot for is cost and reliability is a concern. Just a suggestion. ___ 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] Cycling of Peltier junction
Does anybody know about using the same Peltier junction for both heating and cooling? I'm concerned about thermal/mechanical shock when changing the polarity back-n-forth between hot and cold. Maybe there needs to be a controlled ramp, if so then how do I figure out the rate? Why: I'm in the process of building a small environmental chamber for my home lab. The volume is ~30 liter, target temp range of 0C to 60C. For the cooling side I am using water circulation (radiator, pump, reservoir water block) and Peltier junctions. At first I was planning to have two separate systems, one for heating and one for cooling, but then I got to thinking that using just the water and Peltier could be used for both. I will be using a PID for temp control, and two TEC1-12726 Peltier Qcmax(w)= ~240 △T =0j Regards, Jerome --- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. --- ___ 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] Timing Distribution in Mountainous Terrain
On Thu, September 9, 2010 3:17 pm, John Anderson wrote: Hmmm...I design such timing systems for Moto data radios, and 30nS sync is going to be very hard to achieve in reality. Over a few hundred miles you're going to have OTA time of flight issues, temperature dependencies, etc. Over the years this has been tried, usually with dismal success in the reliability department. You might get the system working in the summer, and then when winter hits and snow builds up on the GPS antennas your network goes down. Or, spring hit with a lot of atmospheric turbulance and you get all sorts of reflection / refraction effects, and trying to sync up time slots that close will be almost impossible. It might work oneweek, and not the next. We are not syncing time slots for communications. The timing requirement is for determining aircraft position by multilateration. Timing errors translate into position uncertainty. What's your carrier freq? In mountainous regions you'll probably have better luck at the lower end. Please tell me you're not trying this at GHz freqs at higher, rocky elevations. Signal emitted by the aircraft is 1090 MHz, pulse-position modulated transponder squitter (Mode C/Mode S). Radio stations receive signal, determine time of reception, and forward the timestamped transmission via landline to a central facility for correlation and position determination. You might find +-1uSec is a good number to shoot for is cost and reliability is a concern. Just a suggestion. 1 us = 1000 ft, which is more uncertainty than they want to deal with. I don't make the requirements, we just have to live with them. We definitely do provide feedback on cost and reliability to those that do dream up the requirements. Ralph ___ 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] Cycling of Peltier junction
For this temp range, thermal shock or reversal should not be a problem. Neither is reversal, just use a (relatively) cheap h-bridge off epay... working out the water temp might be a problem? There will be no problem with h-bridges, as the Peltier junction has very small L-C values, ie not like a motor... Don Jerome Peters Does anybody know about using the same Peltier junction for both heating and cooling? I'm concerned about thermal/mechanical shock when changing the polarity back-n-forth between hot and cold. Maybe there needs to be a controlled ramp, if so then how do I figure out the rate? Why: I'm in the process of building a small environmental chamber for my home lab. The volume is ~30 liter, target temp range of 0C to 60C. For the cooling side I am using water circulation (radiator, pump, reservoir water block) and Peltier junctions. At first I was planning to have two separate systems, one for heating and one for cooling, but then I got to thinking that using just the water and Peltier could be used for both. I will be using a PID for temp control, and two TEC1-12726 Peltier Qcmax(w)= ~240 $B$(BT =0j Regards, Jerome --- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. --- ___ 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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.
Re: [time-nuts] Cycling of Peltier junction
Jerome, All of the modern temperature calibration dry-wells that support both lower-than-ambient and higher-than-ambient set points, within the same well cavity, do so by changing the current direction through (typically) several Peltier junctions attached to a massive aluminum block. See Hart Scientific (Fluke) 9170 9171 Metrology Dry-Well Calibrators. The low and high set point temperature ranges are much more limited than say a resistive element type that would extent upward 600-1000 C due to the limitation of the Peltier junction. I routinely go from 0.0C to 100C (and back) in typical calibration procedures and there is no intentional current limiting ramp necessary other than staying within the power envelope of the device. You only need to make sure that thermal conduction on both sides on the junction device is adequately. In your case, forced air cooled heatsink on one side and a liquid heat exchanger on the other. With good design, you should be able to achieve a liquid coolant temperature range of -10C to +100C very easily. A good PID controller, home brew or a Watlow off ebay, will give you very nice set-point control and stability. Been there, done that. Regards... Don From: Jerome Peters jpet...@nvidia.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 9, 2010 2:41:52 PM Subject: [time-nuts] Cycling of Peltier junction Does anybody know about using the same Peltier junction for both heating and cooling? I'm concerned about thermal/mechanical shock when changing the polarity back-n-forth between hot and cold. Maybe there needs to be a controlled ramp, if so then how do I figure out the rate? Why: I'm in the process of building a small environmental chamber for my home lab. The volume is ~30 liter, target temp range of 0C to 60C. For the cooling side I am using water circulation (radiator, pump, reservoir water block) and Peltier junctions. At first I was planning to have two separate systems, one for heating and one for cooling, but then I got to thinking that using just the water and Peltier could be used for both. I will be using a PID for temp control, and two TEC1-12726 Peltier Qcmax(w)= ~240 △T =0j Regards, Jerome --- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. --- ___ 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] Timing Distribution in Mountainous Terrain
1) Your own LORAN? 2) MASERS! ___ 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] Cycling of Peltier junction
Peltier devices have been used as temperature control elements for decades. I've never heard of fatigue failures, but, if I were designing a chamber as you suggest, I'd try to keep the temperature differential across the TE element under maybe 15 to 20F. The harder you push it, the greater the stress. Also, the heat pumping power falls dramatically as the delta-T increases and it's a situation of rapidly deminishing returns. I'd not worry much about ramping the drive. FWIW, -John === Does anybody know about using the same Peltier junction for both heating and cooling? I'm concerned about thermal/mechanical shock when changing the polarity back-n-forth between hot and cold. Maybe there needs to be a controlled ramp, if so then how do I figure out the rate? Why: I'm in the process of building a small environmental chamber for my home lab. The volume is ~30 liter, target temp range of 0C to 60C. For the cooling side I am using water circulation (radiator, pump, reservoir water block) and Peltier junctions. At first I was planning to have two separate systems, one for heating and one for cooling, but then I got to thinking that using just the water and Peltier could be used for both. I will be using a PID for temp control, and two TEC1-12726 Peltier Qcmax(w)= ~240 $B$(BT =0j Regards, Jerome --- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. --- ___ 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] Timing Distribution in Mountainous Terrain
I would agree with the many comments. Loran first choice in europe. Oooops we killed it here. 30ns speed of light issues. Think you need a synchronized RB or CS. But what on earth needs 30ns in a radio. On Thu, Sep 9, 2010 at 5:11 PM, Chris Howard ch...@elfpen.com wrote: 1) Your own LORAN? 2) MASERS! ___ 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] Cycling of Peltier junction
There is a reference to thermomechanical fatigue in Peltier devices with respect to the effect of peltier device ripple current on the longevity of the Peltier devices in the HP Journal article on an optical power meter. Bruce J. Forster wrote: Peltier devices have been used as temperature control elements for decades. I've never heard of fatigue failures, but, if I were designing a chamber as you suggest, I'd try to keep the temperature differential across the TE element under maybe 15 to 20F. The harder you push it, the greater the stress. Also, the heat pumping power falls dramatically as the delta-T increases and it's a situation of rapidly deminishing returns. I'd not worry much about ramping the drive. FWIW, -John === Does anybody know about using the same Peltier junction for both heating and cooling? I'm concerned about thermal/mechanical shock when changing the polarity back-n-forth between hot and cold. Maybe there needs to be a controlled ramp, if so then how do I figure out the rate? Why: I'm in the process of building a small environmental chamber for my home lab. The volume is ~30 liter, target temp range of 0C to 60C. For the cooling side I am using water circulation (radiator, pump, reservoir water block) and Peltier junctions. At first I was planning to have two separate systems, one for heating and one for cooling, but then I got to thinking that using just the water and Peltier could be used for both. I will be using a PID for temp control, and two TEC1-12726 Peltier Qcmax(w)= ~240 $B$(BT =0j Regards, Jerome --- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. --- ___ 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] Cycling of Peltier junction
Can you just close the system and let the item self heat. Then you only ever have a cooling problem. Seems I am familiar with a very large computer manufacture who does it that way. On Thu, Sep 9, 2010 at 5:14 PM, J. Forster j...@quik.com wrote: Peltier devices have been used as temperature control elements for decades. I've never heard of fatigue failures, but, if I were designing a chamber as you suggest, I'd try to keep the temperature differential across the TE element under maybe 15 to 20F. The harder you push it, the greater the stress. Also, the heat pumping power falls dramatically as the delta-T increases and it's a situation of rapidly deminishing returns. I'd not worry much about ramping the drive. FWIW, -John === Does anybody know about using the same Peltier junction for both heating and cooling? I'm concerned about thermal/mechanical shock when changing the polarity back-n-forth between hot and cold. Maybe there needs to be a controlled ramp, if so then how do I figure out the rate? Why: I'm in the process of building a small environmental chamber for my home lab. The volume is ~30 liter, target temp range of 0C to 60C. For the cooling side I am using water circulation (radiator, pump, reservoir water block) and Peltier junctions. At first I was planning to have two separate systems, one for heating and one for cooling, but then I got to thinking that using just the water and Peltier could be used for both. I will be using a PID for temp control, and two TEC1-12726 Peltier Qcmax(w)= ~240 △T =0j Regards, Jerome --- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. --- ___ 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] Timing Distribution in Mountainous Terrain
On Sep 9, 2010, at 12:03 PM, Ralph Smith wrote: 1e-11 only buys you 3000 seconds of drift before blowing the 30 ns budget. Without going to cesium we will most likely need some form of mutually visible synchronization. How about a rubidium or cesium standard at each site for holdover, with an extra cesium standard that is physically carried from site to site (say, by helicopter) during an extended holdover period to distribute a common time reference around? Or, a specially-equipped aircraft which is periodically flown along paths visible to multiple antenna sites during an extended holdover in order to adjust out drift based on measured round-trip times between the sites and aircraft? In effect, flying your own low-altitude satellite over the sites when the GPS system is down. These may be silly ideas, but brainstorming is fun. -- Mark J. Blair, NF6X n...@nf6x.net Web page: http://www.nf6x.net/ GnuPG public key available from my web page. ___ 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] Cycling of Peltier junction
Wow, So many people have helped - Thanks! I see your point, it can be done without changing the polarity, just control how much heat is carried away... very interesting. Regards, Jerome -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: Thursday, September 09, 2010 2:55 PM To: j...@quik.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Cycling of Peltier junction Can you just close the system and let the item self heat. Then you only ever have a cooling problem. Seems I am familiar with a very large computer manufacture who does it that way. On Thu, Sep 9, 2010 at 5:14 PM, J. Forster j...@quik.com wrote: Peltier devices have been used as temperature control elements for decades. I've never heard of fatigue failures, but, if I were designing a chamber as you suggest, I'd try to keep the temperature differential across the TE element under maybe 15 to 20F. The harder you push it, the greater the stress. Also, the heat pumping power falls dramatically as the delta-T increases and it's a situation of rapidly deminishing returns. I'd not worry much about ramping the drive. FWIW, -John === Does anybody know about using the same Peltier junction for both heating and cooling? I'm concerned about thermal/mechanical shock when changing the polarity back-n-forth between hot and cold. Maybe there needs to be a controlled ramp, if so then how do I figure out the rate? Why: I'm in the process of building a small environmental chamber for my home lab. The volume is ~30 liter, target temp range of 0C to 60C. For the cooling side I am using water circulation (radiator, pump, reservoir water block) and Peltier junctions. At first I was planning to have two separate systems, one for heating and one for cooling, but then I got to thinking that using just the water and Peltier could be used for both. I will be using a PID for temp control, and two TEC1-12726 Peltier Qcmax(w)= ~240 △T =0j Regards, Jerome --- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. --- ___ 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] PTS040 problems, was manual for Racal 1998 and 1999....
In a message dated 09/09/2010 20:05:14 GMT Daylight Time, eb4...@cembreros.jazztel.es writes: Yes, I have downloaded them for the PTS 160, 500, 3200 and X10 and you are correct, all those synthesizers share the same basic principles and maybe some modules, but I found that the frequencies involved are not the same. Hi Ignacio You might also want to download the manual for the PTS310 from Didier's site, that and the PTS160 manual probably incorporate most of the variations that matter. - The problem with mine is that it shows frequency errors at some settings and when it happens the generated signal shows bad spectral purity. Maybe a module went mistuned due to a component aging or failure and having the right manual while is not a must it would be very helpfull. - I've not owned a PTS040 so am not familiar with its structure, but my guess is it will either include a bank of DM1000 modules for steps below 100KHz as per the PTS160 or a fine resolution section similar to the PTS310. If it includes a bank of DM1000 modules, possibly DM2000 modules if a later unit, these should all be interchangeable and, assuming none are faulty can be swapped around without causing any functional problems. The modules plug in and are retained with three screws from below. You then have the option of swapping DM1000 modules around to try and isolate the fault to a particular module or could perhaps identify the likely module by looking for a pattern in those settings where the problem occurs. This, of course, assumes that the problems are occurring at switch settings for increments below 100KHz. If the problem seems to be associated with higher increment switching the substitution option no longer applies but there are then less modules to worry about. If the PTS040 uses a fine resolution section that does make life a bit more awkward but, as I commented earlier, it's possible that the PTS310 manual might then be of assistance. I might be able to be a bit more specific if you could send me a list of the module numbers fitted, or perhaps some high res photos of top and bottom views with the covers off, and perhaps an idea of any pattern to the problem frequencies? 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.
Re: [time-nuts] Timing Distribution in Mountainous Terrain
Ralph, so you're talking about 5.8E-14, right? I'd think no off the shelf caesium, even when run in a temperature controlled environment, will get you there. Well, at a first glance, a 5071A with high performance tube would, if you keep any environmental effects out. So you'll likely need to sync them through a reliable and reproduceable link. Just a quick shot though. Adrian Ralph Smith schrieb: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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] Timing Distribution in Mountainous Terrain
Adrian wrote: Ralph, so you're talking about 5.8E-14, right? I'd think no off the shelf caesium, even when run in a temperature controlled environment, will get you there. Well, at a first glance, a 5071A with high performance tube would, if you keep any environmental effects out. So you'll likely need to sync them through a reliable and reproduceable link. Just a quick shot though. Adrian I would like to point out that the environmental sensitivities of the 5071A are unmeasureable, and the measurement threshold is far below 5.8E-14. I would estimate that the 5071A (and ONLY the 5071A among commercial clocks) could get the job done provided that you could compare its frequency to GPS to the stated accuracy. This would be using the 5071 as a secondary standard. You still need to deal with the short term stability of the 5071A, depending on your system needs. JPL uses H masers as flywheels. Rick Karlquist N6RK member 5071A design team ___ 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] Timing Distribution in Mountainous Terrain
See TVB's site for an experiment with moving CS standards around... Adrian Ralph, so you're talking about 5.8E-14, right? I'd think no off the shelf caesium, even when run in a temperature controlled environment, will get you there. Well, at a first glance, a 5071A with high performance tube would, if you keep any environmental effects out. So you'll likely need to sync them through a reliable and reproduceable link. Just a quick shot though. Adrian Ralph Smith schrieb: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. If we were able to have each site within line of sight of another, and could form a network including all sites, we could do differential time measurement between the mutually visible sites and correct in that way. Unfortunately, that is not the case. Absolute time accuracy is not critical, but relative time accuracy is. Does anyone out there have any ideas? Thanks, Ralph AB4RS ___ 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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.
Re: [time-nuts] Cycling of Peltier junction
It's kind of important for the heating and cooling systems to be able to overlap. I think you will get much tighter control if you use a simple resistance heater and the Peltier cooler. -Chuck Harris Jerome Peters wrote: Does anybody know about using the same Peltier junction for both heating and cooling? I'm concerned about thermal/mechanical shock when changing the polarity back-n-forth between hot and cold. Maybe there needs to be a controlled ramp, if so then how do I figure out the rate? ___ 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] Timing Distribution in Mountainous Terrain
Some form of low frequency broadcast system might work as a GPS backup. This paper provides a comparison of Loran C vs GPS for time transfers. While Loran C is history in the US, this might give some indication of what could be expected from a low frequency broadcast system. http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2doc=GetTRDoc.pdfAD=ADA427851 I suspect buying cesium oscilators is likely to be cheaper than setting up a low frequency broadcast system,designing receivers etc. But there might be a more or less off the shelf way to do this ? Just a random thought. - Original Message From: Hal Murray hmur...@megapathdsl.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 9, 2010 2:57:50 PM Subject: Re: [time-nuts] Timing Distribution in Mountainous Terrain Neat problem. Please let us know what you finally do. 1e-11 only buys you 3000 seconds of drift before blowing the 30 ns budget. Without going to cesium we will most likely need some form of mutually visible synchronization. How many Cesiums do you need? What do they cost these days? (at that volume and govt rates) What's the long term maintenance cost? Can you afford to design, debug, and qualify something else at that total price? My straw man for an alternative would be to use the transmitter on the airplanes as the signal source. I think that works if you have extra ground stations covering at least some regions which will have enough airplanes in them to keep the system calibrated. But maybe you need those extra ground stations anyway so that the whole system doesn't fall apart when fire/earthquake/tornado/whatever takes out one ground station. (If so, you have to think about what happens if one station does go out.) -- 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. ___ 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] PTS040 problems, was manual for Racal 1998 and 1999....
Nigel, I have the pictures but it is 02:30 LT here and I have to go to bed. Tomorrow I'll send you the pictures and I' give you a more extensive description of the symptoms. I believe now that the 7th DM module is not working well when the input is at one of its band limits. Thank for your support. Ignacio, EB4APL gandal...@aol.com wrote: In a message dated 09/09/2010 20:05:14 GMT Daylight Time, eb4...@cembreros.jazztel.es writes: Yes, I have downloaded them for the PTS 160, 500, 3200 and X10 and you are correct, all those synthesizers share the same basic principles and maybe some modules, but I found that the frequencies involved are not the same. Hi Ignacio You might also want to download the manual for the PTS310 from Didier's site, that and the PTS160 manual probably incorporate most of the variations that matter. - The problem with mine is that it shows frequency errors at some settings and when it happens the generated signal shows bad spectral purity. Maybe a module went mistuned due to a component aging or failure and having the right manual while is not a must it would be very helpfull. - I've not owned a PTS040 so am not familiar with its structure, but my guess is it will either include a bank of DM1000 modules for steps below 100KHz as per the PTS160 or a fine resolution section similar to the PTS310. If it includes a bank of DM1000 modules, possibly DM2000 modules if a later unit, these should all be interchangeable and, assuming none are faulty can be swapped around without causing any functional problems. The modules plug in and are retained with three screws from below. You then have the option of swapping DM1000 modules around to try and isolate the fault to a particular module or could perhaps identify the likely module by looking for a pattern in those settings where the problem occurs. This, of course, assumes that the problems are occurring at switch settings for increments below 100KHz. If the problem seems to be associated with higher increment switching the substitution option no longer applies but there are then less modules to worry about. If the PTS040 uses a fine resolution section that does make life a bit more awkward but, as I commented earlier, it's possible that the PTS310 manual might then be of assistance. I might be able to be a bit more specific if you could send me a list of the module numbers fitted, or perhaps some high res photos of top and bottom views with the covers off, and perhaps an idea of any pattern to the problem frequencies? 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] PTS040 problems, was manual for Racal 1998 and 1999....
Oops, I intended to send it only to Nigel. Sorry for the BW Ignacio, EB4APL EB4APL escribió: Nigel, I have the pictures but it is 02:30 LT here and I have to go to bed. Tomorrow I'll send you the pictures and I' give you a more extensive description of the symptoms. I believe now that the 7th DM module is not working well when the input is at one of its band limits. Thank for your support. Ignacio, EB4APL ___ 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] Timing Distribution in Mountainous Terrain
Hi If 30 ns is the system goal, then you have a lot more to budget for than simple clock error. You could easily be below 10 ns for just the clock portion of the budget. I suspect that multiple 5071's and a maser or two at each site will be the ultimate solution if each must stand alone for 6 days and the set of 10 stay within 30 ns p-p. If reliability planning includes 6 days past end of GPS it also likely includes significant redundancy and more than a few 9's in the confidence factor. I suspect it's cheaper to buy the 5071's than to have a half dozen SR-71 category aircraft ready to climb high enough to act as common view targets. High altitude balloons might work pretty well and they would be cheaper to keep in hot standby mode. Bob On Sep 9, 2010, at 8:01 PM, Rick Karlquist rich...@karlquist.com wrote: Adrian wrote: Ralph, so you're talking about 5.8E-14, right? I'd think no off the shelf caesium, even when run in a temperature controlled environment, will get you there. Well, at a first glance, a 5071A with high performance tube would, if you keep any environmental effects out. So you'll likely need to sync them through a reliable and reproduceable link. Just a quick shot though. Adrian I would like to point out that the environmental sensitivities of the 5071A are unmeasureable, and the measurement threshold is far below 5.8E-14. I would estimate that the 5071A (and ONLY the 5071A among commercial clocks) could get the job done provided that you could compare its frequency to GPS to the stated accuracy. This would be using the 5071 as a secondary standard. You still need to deal with the short term stability of the 5071A, depending on your system needs. JPL uses H masers as flywheels. Rick Karlquist N6RK member 5071A design team ___ 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] Timing Distribution in Mountainous Terrain
Radar calibration: You could do a clock calibration if you knew some fixed reference points to sweep. Put some towers up on a few of the taller peaks in the area. Measure them while the GPS is running and use them for reference to keep the clocks right when GPS is down. But masers sound like more fun. -- Chris ___ 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] Timing Distribution in Mountainous Terrain
On Sep 9, 2010, at 9:27 PM, Bob Camp wrote: Hi If 30 ns is the system goal, then you have a lot more to budget for than simple clock error. You could easily be below 10 ns for just the clock portion of the budget. I suspect that multiple 5071's and a maser or two at each site will be the ultimate solution if each must stand alone for 6 days and the set of 10 stay within 30 ns p-p. If reliability planning includes 6 days past end of GPS it also likely includes significant redundancy and more than a few 9's in the confidence factor. I suspect it's cheaper to buy the 5071's than to have a half dozen SR-71 category aircraft ready to climb high enough to act as common view targets. High altitude balloons might work pretty well and they would be cheaper to keep in hot standby mode. I expect the more likely outcome to be a reality adjustment and relaxing of the requirements, possibly with some form of satellite common view target. Ralph ___ 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] Timing Distribution in Mountainous Terrain
On Sep 9, 2010, at 8:01 PM, Rick Karlquist wrote: I would like to point out that the environmental sensitivities of the 5071A are unmeasureable, and the measurement threshold is far below 5.8E-14. I would estimate that the 5071A (and ONLY the 5071A among commercial clocks) could get the job done provided that you could compare its frequency to GPS to the stated accuracy. This would be using the 5071 as a secondary standard. You still need to deal with the short term stability of the 5071A, depending on your system needs. JPL uses H masers as flywheels. I would imagine the cost of a 5071A per radio station would make the check writers swallow hard, and adding an H Maser into the mix would really get their attention. Especially if you need redundancy. Thanks for all the input. Being asked to design for Armegeddon begs the question of what will the system do after that. Ralph ___ 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] Timing Distribution in Mountainous Terrain
We should start seeing used Loran transmitters on ebay pretty soon (!), and it should not be too hard to build a timing receiver using this signal. If you just want timing, one transmitter may be enough to cover the area of interest. The low frequency Loran signals do go relatively well over hills, but mountains, I am not sure. Now, I do not know if this would provide the needed precision directly, but it might be enough to servo high quality references through a PLL. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Mark Spencer mspencer12...@yahoo.ca Sender: time-nuts-boun...@febo.com Date: Thu, 9 Sep 2010 17:36:39 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Timing Distribution in Mountainous Terrain Some form of low frequency broadcast system might work as a GPS backup. This paper provides a comparison of Loran C vs GPS for time transfers. While Loran C is history in the US, this might give some indication of what could be expected from a low frequency broadcast system. http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2doc=GetTRDoc.pdfAD=ADA427851 I suspect buying cesium oscilators is likely to be cheaper than setting up a low frequency broadcast system,designing receivers etc. But there might be a more or less off the shelf way to do this ? Just a random thought. - Original Message From: Hal Murray hmur...@megapathdsl.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thu, September 9, 2010 2:57:50 PM Subject: Re: [time-nuts] Timing Distribution in Mountainous Terrain Neat problem. Please let us know what you finally do. 1e-11 only buys you 3000 seconds of drift before blowing the 30 ns budget. Without going to cesium we will most likely need some form of mutually visible synchronization. How many Cesiums do you need? What do they cost these days? (at that volume and govt rates) What's the long term maintenance cost? Can you afford to design, debug, and qualify something else at that total price? My straw man for an alternative would be to use the transmitter on the airplanes as the signal source. I think that works if you have extra ground stations covering at least some regions which will have enough airplanes in them to keep the system calibrated. But maybe you need those extra ground stations anyway so that the whole system doesn't fall apart when fire/earthquake/tornado/whatever takes out one ground station. (If so, you have to think about what happens if one station does go out.) -- 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. ___ 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] Timing Distribution in Mountainous Terrain
Loran? Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark J. Blair Sent: Thursday, September 09, 2010 1:48 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Timing Distribution in Mountainous Terrain On Sep 9, 2010, at 10:42, Ralph Smith ra...@ralphsmith.org wrote: Paranoia. People making the requirements are concerned with GPS going away due to solar flare or some other reason. Hmm... So the decision makers think that after a solar flare or some other reason (hostile destruction of the birds, perhaps?) takes out the GPS system, it'll be back up and running within six days? That sounds optimistic to me. It sounds to me more like you would need to function indefinitely without GPS, and just use GPS for initial position survey and as a convenient way to synchronize to external time reference (with ground-based backup methods in place and periodically tested). ___ 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] Timing Distribution in Mountainous Terrain
Loran? What was the stability of Loran when used to distribute time? (I'm assuming I can use something like GPS for calibration.) Wikipedia says: The absolute accuracy of LORAN-C varies from 0.10-0.25-nautical-mile (185-463 m). Repeatable accuracy is much greater, typically from 60-300-foot (18-91 m). 60 feet would make it hard to get 30 ns accuracy, and that's probably at sea rather than in the mountains. -- 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.
Re: [time-nuts] Timing Distribution in Mountainous Terrain
On Fri, Sep 10, 2010 at 06:17, Mark J. Blair n...@nf6x.net wrote: Or, a specially-equipped aircraft which is periodically flown along paths visible to multiple antenna sites during an extended holdover in order to adjust out drift based on measured round-trip times between the sites and aircraft? In effect, flying your own low-altitude satellite over the sites when the GPS system is down. Assuming there are multiple overflights per hour, which are visible at more than 4(?) sites at the same time, would there be enough information to steer the clocks? The correction would not need to be in real time, either. -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ 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] Timing Distribution in Mountainous Terrain
Ralph Smith wrote: On Thu, September 9, 2010 1:10 pm, Matthew Kaufman wrote: On 9/9/2010 8:37 AM, Ralph Smith wrote: We have a requirement for approximately ten radio sites to be synchronized to within 30 ns of each other. 30 ns seems a little closer than most radio site applications need... what drives this requirement? Aircraft surveillance using multilateration. and presumably some form of bistatic radar with an illuminator and multiple receviers isn't going to cut it? You're fairly close.. is any RF method out of bounds? Could you radiate a low frequency signal that propagates by ground wave? (e.g. Omega.. but I don't think it was anywhere near nanoseconds..) Even a really, really good ovenized quartz oscillator isn't going to be that good. You're looking for 1E-13 sorts of precision, right (50 ns out of 500,000 seconds). I seem to recall numbers like 1 part in 1E10 over 400 days. You might do better with selected units, but this is million dollar a copy sort of units. The Cassini USO drifts between 1E-12 and 1E-11 per day. You're really looking at Cs standards... (about 2E-14 at 1E6 seconds) Ordinarily you could throw in an appropriate GPSDO and be done with it. However, we also have the reqirement to be able to operate independent of GPS for up to six days. Wow, ok, and what drives *that* requirement? Can you use any other Paranoia. People making the requirements are concerned with GPS going away due to solar flare or some other reason. mutually visible thing, or do we assume all satellites have vanished from orbit? No satellites. Thanks, Ralph ___ 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] Timing Distribution in Mountainous Terrain
Ralph Smith wrote: O We are not syncing time slots for communications. The timing requirement is for determining aircraft position by multilateration. Timing errors translate into position uncertainty. What's your carrier freq? In mountainous regions you'll probably have better luck at the lower end. Please tell me you're not trying this at GHz freqs at higher, rocky elevations. Signal emitted by the aircraft is 1090 MHz, pulse-position modulated transponder squitter (Mode C/Mode S). Radio stations receive signal, determine time of reception, and forward the timestamped transmission via landline to a central facility for correlation and position determination. and presumably, you have only one interrogation transmitter, and many listeners? (otherwise you could pulse each one in turn and essentially get a set of 2 way ranges to solve with) I realize you're trying to do multilateration.. BUT, if you measure angle of arrival too, then you can throw that into the solution, and you can tolerate a greater uncertainty in the range measurement. There's also the whole using physics constraints... combine multiple measurements, and model the vehicle dynamics. You've basically got a make a bunch of measurements and combine them, hoping to get a root(N) improvement problem. As you've noted, to get from 1000 ft to 30 ft requires a 30 fold improvement, implying a 1000 measurements.. Yow.. ___ 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] Timing Distribution in Mountainous Terrain
Ralph Smith wrote: On Sep 9, 2010, at 8:01 PM, Rick Karlquist wrote: I would like to point out that the environmental sensitivities of the 5071A are unmeasureable, and the measurement threshold is far below 5.8E-14. I would estimate that the 5071A (and ONLY the 5071A among commercial clocks) could get the job done provided that you could compare its frequency to GPS to the stated accuracy. This would be using the 5071 as a secondary standard. You still need to deal with the short term stability of the 5071A, depending on your system needs. JPL uses H masers as flywheels. I would imagine the cost of a 5071A per radio station would make the check writers swallow hard, and adding an H Maser into the mix would really get their attention. Especially if you need redundancy. there's also the possibility mentioned earlier of using a lower quality standard at each station and flying (driving) a higher quality clock (5071) around often enough to keep them trued up. If it's far enough in the future.. Hg ion traps have a lot of potential.. smaller, lower power, etc. than Cs I think, though, that some sort of self calibrating array using the target of interest is a better scheme.. multiple receivers at each site separated by some distance. Getting milliradian angular resolution is a piece of cake. ___ 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.
