Hi On Jun 22, 2013, at 8:13 PM, Magnus Danielson <magnus@rubidium.dyndns.org> wrote: > On 06/23/2013 01:52 AM, Jim Lux wrote: >> On 6/22/13 4:38 PM, Magnus Danielson wrote: >> >>>> >>>> electromechanical.. like omega receivers. rotary transformers can do >>>> very high quality trig functions, but do you actually need trig >>>> functions assuming you're just solving for X,Y,Z,T. >>> >>> Oh yes. Check IS-GPS-200F, clause 20.3.3.4.3 User Algorithm for >>> Ephemeris Determination, found on page 113 and forward. The Table 20-IV >>> contains the actual formulas. The Kepler's Equation for Eccentric >>> Anomaly is a bit annoying, since it is not in closed form, so one way or >>> another of approximation iteration is needed. >>> >>> Quite a bit of trigonometry goes on just to have each tracked satellites >>> current position estimated, such that the pseudo-range value taken for >>> the bird can be diffed out with the position. That process becomes >>> trivial if the position is known and only time is needed, given that we >>> cranked out the birds X, Y, Z and T position, which requires >>> trigonometry. >> >> Yes, but that trig can be done VERY slowly, since the cycle time is 12 >> hours, which is why a resolver/rotary transformer approach seems viable. >> >> (rather, than, say, integrating the satellite state vector) > > Indeed. > >>> >>>> Are you allowed to externally supply the almanac, in the form of a >>>> electromechanical system. The satellites are in circular orbits and >>>> fairly stable, and with multiple satellites in the same plane. >>> >>> You could naturally cheat in several interesting ways, but you need >>> fairly accurate X, Y and Z values for the birds at any given time. >> >> >> How accurate?? Resolvers are good to about 16 bit accuracy, so I guess 1 >> part in 60,000. if the orbit circumference is 163 Mm, then a resolver >> can determine the position to a few km. >> However, I don't know that that is good enough. If you need to know to 1 >> chip at C/A code rates, 1 microsecond, that's a pretty small fraction of >> one 12 hour rev of 43200 seconds. But maybe not. > > Hmm. You could tabulate it even. It would be quite a bit of core-memory, Core and tubes??? Hmmm….. Bob > but achieveable. > > Oh, and it isn't full 43200 s, it's only about 11 hours and 58 min. > >>>> Actually, how bad would your time estimate be if you just assumed >>>> perfect circular orbits with no higher order corrections? >>> >>> Grabbing a modern set of data, doing the calculations with and without >>> the proper values would tell you. I would not be surprised if it where >>> way over the km off. On the other hand, the precision we talk about in >>> general already throws us off sufficiently, so who cares. >>> >>> One should realize that we talk about tens of Mm numbers in pseudo-range >>> distances. >>> >> >> So I think you probably can't get a position fix within 10km, but hey, >> what a beast it would be. > > Oh yes. > > With a RAIM algorithm you could use extra channels to overcome deficiencies in the crudeness of the calculations. > > Would be neat if there would be a PLL steering of the revolving calender to maintain with minimum error. The T error would be a natural detector to use. Extra grade if individual birds got adjusted. > > 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.

Hi Bob, On 06/23/2013 02:35 AM, Bob Camp wrote: > Hi > > How stable a 1.023 oscillator? How much pull range on that oscillator? Hmmmm….. The 1.57542 GHz carrier gets you to +/- 6 kHz which is about +/- 3.8 ppm, so it's not that hard to do. Cheers, Magnus

Hi Bob, On 06/23/2013 02:35 AM, Bob Camp wrote: >>> How accurate?? Resolvers are good to about 16 bit accuracy, so I guess 1 >>> part in 60,000. if the orbit circumference is 163 Mm, then a resolver >>> can determine the position to a few km. >>> However, I don't know that that is good enough. If you need to know to 1 >>> chip at C/A code rates, 1 microsecond, that's a pretty small fraction of >>> one 12 hour rev of 43200 seconds. But maybe not. >> >> Hmm. You could tabulate it even. It would be quite a bit of core-memory, > > Core and tubes??? Hmmm….. We could get you some AC137 to play with if you want... Cheers, Magnus

On 6/22/13 5:35 PM, Bob Camp wrote: > Hi > > How stable a 1.023 oscillator? How much pull range on that oscillator? Hmmmm….. Doppler is the big component..several kHz..

Hi It's the combination of swing required for the doppler and the stability required for a simple correlator to do it's job that is the issue. A couple ppm swing - not so hard. A few tenths of a ppb stability not so hard. Both at the same time - starting to get hard. If this is "tube only" doing all that without varicap diodes - that gets interesting. Bob On Jun 22, 2013, at 9:13 PM, Magnus Danielson <magnus@rubidium.dyndns.org> wrote: > Hi Bob, > > On 06/23/2013 02:35 AM, Bob Camp wrote: >> Hi >> >> How stable a 1.023 oscillator? How much pull range on that oscillator? Hmmmm….. > > The 1.57542 GHz carrier gets you to +/- 6 kHz which is about +/- 3.8 ppm, so it's not that hard to do. > > 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.

Hi AC137 doesn't ring any bells. True tube core (no solid state at all) isn't something that was dimensioned in K words. A couple hundred words was pretty big stuff. "Quite a bit" of core done that way is a lot of tubes. As the number of tubes goes up, the time to failure comes down….. hours … minutes … who knows. Bob On Jun 22, 2013, at 9:14 PM, Magnus Danielson <magnus@rubidium.dyndns.org> wrote: > Hi Bob, > > On 06/23/2013 02:35 AM, Bob Camp wrote: >>>> How accurate?? Resolvers are good to about 16 bit accuracy, so I guess 1 >>>> part in 60,000. if the orbit circumference is 163 Mm, then a resolver >>>> can determine the position to a few km. >>>> However, I don't know that that is good enough. If you need to know to 1 >>>> chip at C/A code rates, 1 microsecond, that's a pretty small fraction of >>>> one 12 hour rev of 43200 seconds. But maybe not. >>> >>> Hmm. You could tabulate it even. It would be quite a bit of core-memory, >> >> Core and tubes??? Hmmm….. > > We could get you some AC137 to play with if you want... > > 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.

On 6/23/2013 14:40, Bob Camp wrote: > Hi > > AC137 doesn't ring any bells. True tube core (no solid state at all) isn't something that was dimensioned in K words. A couple hundred words was pretty big stuff. "Quite a bit" of core done that way is a lot of tubes. As the number of tubes goes up, the time to failure comes down….. hours … minutes … who knows. > > Bob > Yeah, it gets to be like the cross country aircraft races in the 20's. The mechanic had to fly with the pilot. (The MTBF of many of the engines used was measured in hours.) If necessary he had to climb out on the cowling while in flight to change plugs and fix whatever possible without landing. What would OSHA say about that? Needless to say future generations will probably find lots of aircraft spark plug artifacts in their digs. Brian/K3KO ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5932 - Release Date: 06/22/13

Magnetic cores were not invented until the 1950's and realy cam into use as tubes were beibg replaced by SS. But there isnot reason yu can't build a tube computer with core memory. I have actually seen and used a computer that had one megabyte of core memory. The stuff was still in use in the late 1970s 1MB was a lot of RAM in 1975. You can have very good reliability with tube circuits. It was just that few people wanted to pay for it. Down time was cheaper. It is not hard to add redundancy to a circuit but it does have a huge cost multiplier effect. 4x or 5x the price. One simple way is to use 3 or 4 tubes with their output tied to a resistive adder. If one tube fails the result (because it is binary) is still the same. With computers no one would pay for fault tolerant design until it was reasonably affordable. Even today we mainly just put up with failure except for airplane controllers, huge web sites like Amazon and the like. On Sun, Jun 23, 2013 at 9:53 AM, Brian Alsop <alsopb@nc.rr.com> wrote: > On 6/23/2013 14:40, Bob Camp wrote: > >> Hi >> >> AC137 doesn't ring any bells. True tube core (no solid state at all) >> isn't something that was dimensioned in K words. A couple hundred words was >> pretty big stuff. "Quite a bit" of core done that way is a lot of tubes. As >> the number of tubes goes up, the time to failure comes down….. hours … >> minutes … who knows. >> >> Bob >> >> > Yeah, it gets to be like the cross country aircraft races in the 20's. The > mechanic had to fly with the pilot. (The MTBF of many of the engines used > was measured in hours.) If necessary he had to climb out on the cowling > while in flight to change plugs and fix whatever possible without landing. > What would OSHA say about that? > > Needless to say future generations will probably find lots of aircraft > spark plug artifacts in their digs. > > Brian/K3KO > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2242 / Virus Database: 3199/5932 - Release Date: 06/22/13 > > > ______________________________**_________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/** > mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > and follow the instructions there. > -- Chris Albertson Redondo Beach, California

Hi I've both used and worked on core memory machines. They ones I have seen all used solid state devices in the core memory sections of the machine. I've never heard of a pure tube machine with more than "register sized" core. Bob On Jun 23, 2013, at 1:47 PM, Chris Albertson <albertson.chris@gmail.com> wrote: > Magnetic cores were not invented until the 1950's and realy cam into use as > tubes were beibg replaced by SS. But there isnot reason yu can't build a > tube computer with core memory. I have actually seen and used a computer > that had one megabyte of core memory. The stuff was still in use in the > late 1970s 1MB was a lot of RAM in 1975. > > You can have very good reliability with tube circuits. It was just that > few people wanted to pay for it. Down time was cheaper. It is not hard to > add redundancy to a circuit but it does have a huge cost multiplier effect. > 4x or 5x the price. One simple way is to use 3 or 4 tubes with their > output tied to a resistive adder. If one tube fails the result (because it > is binary) is still the same. With computers no one would pay for fault > tolerant design until it was reasonably affordable. Even today we mainly > just put up with failure except for airplane controllers, huge web sites > like Amazon and the like. > > > On Sun, Jun 23, 2013 at 9:53 AM, Brian Alsop <alsopb@nc.rr.com> wrote: > >> On 6/23/2013 14:40, Bob Camp wrote: >> >>> Hi >>> >>> AC137 doesn't ring any bells. True tube core (no solid state at all) >>> isn't something that was dimensioned in K words. A couple hundred words was >>> pretty big stuff. "Quite a bit" of core done that way is a lot of tubes. As >>> the number of tubes goes up, the time to failure comes down….. hours … >>> minutes … who knows. >>> >>> Bob >>> >>> >> Yeah, it gets to be like the cross country aircraft races in the 20's. The >> mechanic had to fly with the pilot. (The MTBF of many of the engines used >> was measured in hours.) If necessary he had to climb out on the cowling >> while in flight to change plugs and fix whatever possible without landing. >> What would OSHA say about that? >> >> Needless to say future generations will probably find lots of aircraft >> spark plug artifacts in their digs. >> >> Brian/K3KO >> >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2012.0.2242 / Virus Database: 3199/5932 - Release Date: 06/22/13 >> >> >> ______________________________**_________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/** >> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > 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.

Hi: The SAGE computers, which I had the pleasure of seeing the last two operating, had an all vacuum tube array of core that consisted of 33 planes of 64 x64 cores for about 16K worth of memory. These where all vacuum tube computers. IBM offered a 4K all vacuum tube core storage unit for the 701 and 702, the same unit was built into the 704 and the 705 had a larger core storage with 35 planes of 50 x 80 cores. The Remington Rand Corp. and the RAND Corp. also shipped computers that used core for main storage in the mid 50s which likely used vacuum tube drivers. At that time there where apparently no transistors available that could supply the drive current required for core memory. On 6/23/13 5:29 PM, Bob Camp wrote: > Hi > > I've both used and worked on core memory machines. They ones I have seen all used solid state devices in the core memory sections of the machine. I've never heard of a pure tube machine with more than "register sized" core. > > Bob > > On Jun 23, 2013, at 1:47 PM, Chris Albertson <albertson.chris@gmail.com> wrote: > >> Magnetic cores were not invented until the 1950's and realy cam into use as >> tubes were beibg replaced by SS. But there isnot reason yu can't build a >> tube computer with core memory. I have actually seen and used a computer >> that had one megabyte of core memory. The stuff was still in use in the >> late 1970s 1MB was a lot of RAM in 1975. >> >> You can have very good reliability with tube circuits. It was just that >> few people wanted to pay for it. Down time was cheaper. It is not hard to >> add redundancy to a circuit but it does have a huge cost multiplier effect. >> 4x or 5x the price. One simple way is to use 3 or 4 tubes with their >> output tied to a resistive adder. If one tube fails the result (because it >> is binary) is still the same. With computers no one would pay for fault >> tolerant design until it was reasonably affordable. Even today we mainly >> just put up with failure except for airplane controllers, huge web sites >> like Amazon and the like. >> >> >> On Sun, Jun 23, 2013 at 9:53 AM, Brian Alsop <alsopb@nc.rr.com> wrote: >> >>> On 6/23/2013 14:40, Bob Camp wrote: >>> >>>> Hi >>>> >>>> AC137 doesn't ring any bells. True tube core (no solid state at all) >>>> isn't something that was dimensioned in K words. A couple hundred words was >>>> pretty big stuff. "Quite a bit" of core done that way is a lot of tubes. As >>>> the number of tubes goes up, the time to failure comes down….. hours … >>>> minutes … who knows. >>>> >>>> Bob >>>> >>>> >>> Yeah, it gets to be like the cross country aircraft races in the 20's. The >>> mechanic had to fly with the pilot. (The MTBF of many of the engines used >>> was measured in hours.) If necessary he had to climb out on the cowling >>> while in flight to change plugs and fix whatever possible without landing. >>> What would OSHA say about that? >>> >>> Needless to say future generations will probably find lots of aircraft >>> spark plug artifacts in their digs. >>> >>> Brian/K3KO >>> >>> >>> >>> ----- >>> No virus found in this message. >>> Checked by AVG - www.avg.com >>> Version: 2012.0.2242 / Virus Database: 3199/5932 - Release Date: 06/22/13 >>> >>> >>> ______________________________**_________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/** >>> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >>> and follow the instructions there. >>> >> >> >> -- >> >> Chris Albertson >> Redondo Beach, California >> _______________________________________________ >> 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.