Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs

2010-02-27 Thread jimlux
Mike Feher wrote: In general, what about the old National damn fast and super damn fast LH0032 LH0033? I used to use a lot of those in my designs many years ago. - Mike Gotta really decouple the power supplies on those puppies... ___ time-nuts

Re: [time-nuts] Achieving maximum performance when driving 5370A/B inputs

2010-02-27 Thread jimlux
Bob Camp wrote: Hi Sure never seen any of them on any gear in my junk pile. I also never seen a customer ask for them as an output connector on an oscillator. I wonder how common they actually are. Bob On Feb 27, 2010, at 9:59 PM, Bruce Griffiths wrote: Actually there are miniature

Re: [time-nuts] nubie querie

2010-03-09 Thread jimlux
Paul Boven wrote: Hi Tom, everyone, Tom Van Baak wrote: See: http://www.leapsecond.com/museum/pulsar for some pulsar ADEV stability plots and links to many research papers with all the details. Your page starts with the question if it was possible for an amateur to receive pulsar signals?.

Re: [time-nuts] Thermal Time Constant

2010-03-10 Thread jimlux
Brooke Clarke wrote: Hi Bruce: What does m2K/W mean? See: http://building.dow.com/europe/uk/proddata/styrofoam/thermal.htm 50 mm it's about 1.5 and for 100 mm it's about 3. thermal resistance (you can tell because it's degrees/watt, as opposed to watts/degree which would be conductivity)

Re: [time-nuts] nubie querie

2010-03-10 Thread jimlux
Hal Murray wrote: This, and similar impressive accomplishments, has prompted some lunchtime discussion at work (JPL).. One of us (N5BF) has been contemplating what it would take to do an amateur EarthVenusEarth (after some of his experiments doing EME with 5 watts).. Perhaps a better question

Re: [time-nuts] Thermal Time Constant

2010-03-10 Thread jimlux
Brooke Clarke wrote: Hi Bruce: If a square meter of Styrofoam is 1.5 deg C/W then a cubic inch would be 39.37 * 39.37 * 1.5 or 2,325 deg C/W The DS3231 dissipates about 1 mw when running. I'm not sure how to come up with an allowable temp increase, but suspect it's based on not exceeding

Re: [time-nuts] Thermal time constant

2010-03-10 Thread jimlux
Bob Camp wrote: Hi The gotcha is that you are interested in the amount of heat per cubic foot rather than the amount of heat per pound. You need to take the standard heat per weight numbers and convert them to heat per volume numbers. Of the things you can easily get, copper is good. Steel is

Re: [time-nuts] FE-5680A

2010-03-10 Thread jimlux
Bob Camp wrote: My personal experience suggests that setting one up is indeed a black art known only to the select few. The high priest takes them into the back room and they magically come return in working order several days / weeks / what ever later. High priest goes on vacation - not

Re: [time-nuts] nubie querie

2010-03-10 Thread jimlux
J. Forster wrote: If you like starting from scratch, get a copy of Procedures in Experimental Physics by John Strong. -John And, relevant to the thermal time constant discussion.. That book has a great section on thermal diffusion and conductivity, along with a chart of material

Re: [time-nuts] Thermal time constant

2010-03-11 Thread jimlux
Predrag Dukic wrote: How well depleted it really is? DU has about 1/3 the U235 of natural U, of which less than 1% is U235. All the isotopes are radioactive, but I don't recall what the relative activities are. I think U238 has a half live of 4E9 years or more, so not very many atoms

Re: [time-nuts] Choke Ring Pictures

2010-03-14 Thread jimlux
David C. Partridge wrote: definition of pie 3.1415926535 etc ? Ooops D. And, as my daughter reminds me, today is pi day (in the U.S. where we write the date month/year.. those of you in the rest of the world will have to wait a long time, as there is no April 31st)

Re: [time-nuts] Choke Ring Pictures

2010-03-14 Thread jimlux
Bob Camp wrote: Hi Machining a chunk of Plexiglas sounds like more trouble that I would want to go to for a cheap choke ring setup. Maybe a hemispherical Plexiglass serving bowl take a look at inexpensive light fixtures with hemispherical or spherical plastic globes. Actually,

Re: [time-nuts] enclosure temperature controllers

2010-03-15 Thread jimlux
Don Latham wrote: hello the group: I've just installed a new mercury-free thermostat in my shop. I looked the thing over and realized it has everything needed to control a constant temperature enclosure. There's a diode used as temp sensor,easy to remote with two wires, a place to put two AA

Re: [time-nuts] frying pan antenna

2010-03-16 Thread jimlux
Bob Camp wrote: Hi I certainly won't disagree with the data. I have noticed over the years that past a few MHz antennas out in the fresh air always seem to work better than indoor antennas. It could easily be that there is a *lot* of water in your typical roof. Certainly the water is far from

Re: [time-nuts] frying pan antenna

2010-03-16 Thread jimlux
Bruce Griffiths wrote: Mike Perhaps a single antenna element from the phased array in the following JPL paper would be useful: http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/12178/1/01-0082.pdf I don't know that Mark's antenna is the right kind of thing for GPS. the x-pol off axis is

Re: [time-nuts] frying pan antenna

2010-03-16 Thread jimlux
mike cook wrote: Yes Bruce, I also think that azimuth dependent masking would be useful. I have been suffering from strong reflections from facing buildings at 50m to 100m, which cause sharp departures from the average PPS TI While telling the nav algorithms inside the box would be the most

Re: [time-nuts] Missing GPS satellites

2010-03-26 Thread jimlux
Jeffrey Pawlan wrote: On Thu, 25 Mar 2010, Magnus Danielson wrote: Dear Raj, Oh, sorry, needed a few extra. Wanted to recover the rubidiums and put some on Ebay. I gave a lecture about antennas for operation on 1296MHz last week and mentioned that my vacuum tube power abplifier was

[time-nuts] connectors Re: FW: Re: Low-Cost 6+ GHz Prescaler board for

2010-03-26 Thread jimlux
John Allen wrote: A few notes about the connector. First, I hate BNC connectors. But the BNC is useable to 11 GHz (No vswr spec.), and has a VSWR spec. of 1.3:1 up to 4 GHz. (See link below, about half way down the page.) http://www.amphenolrf.com/products/bnc.asp?N=0sid=4BAAA780568BE17F;

Re: [time-nuts] Anritsu MH-4100A xtal osc (Pete Lancashire)

2010-03-30 Thread jimlux
Dave Baxter wrote: This might interest you http://www.members.shaw.ca/swstuff/gpsreference.html These people can cal' it, they say. http://www.raelectrical.com/services/anritsu-2.htm There are several other hits, including other people who stock used items. Amazing what you find when you

Re: [time-nuts] Surplus Places...

2010-03-31 Thread jimlux
Scott Burris wrote: CH closed briefly to move and is now open in Duarte: http://www.candhsurplus.com/ At Apex, a friend tried to purchase a nose cone from a rocket, but they declined to sell it to him because they were making too much money renting it out to movie studios. Scott That is

Re: [time-nuts] Surplus Places...

2010-03-31 Thread jimlux
Rex wrote: jimlux wrote: Scott Burris wrote: CH closed briefly to move and is now open in Duarte: http://www.candhsurplus.com/ At Apex, a friend tried to purchase a nose cone from a rocket, but they declined to sell it to him because they were making too much money renting it out to movie

Re: [time-nuts] Surplus Places...

2010-04-01 Thread jimlux
saidj...@aol.com wrote: Back in the days (around 1985 or so) Caltech in Pasadena used to have a surplus store on campus. I spent a good time in that store, and still have some of those treasures. Lot's of JPL stuff. Does anyone know if that still exists?? No. doesn't exist. Most

Re: [time-nuts] lunatic fringe time standards

2010-04-14 Thread jimlux
Eugen Leitl wrote: Hi -- a couple somewhat lunatic questions. Figured this would be the best place to ask. Anyone aware of a time standard which compensates in regards to an ideal flat-spacetime-at-rest-relatively-to-cosmic-background reference clock? I realize this is not relevant for any

Re: [time-nuts] lunatic fringe time standards

2010-04-15 Thread jimlux
Bob Camp wrote: Hi The only real limit on a Johnson counter is how clever you get making sure that only one stage is a 1 and all the rest are zeros. There are *lots* of ways to take care of that, each with it's own set of trade offs. One problem with a Johnson counter is that it takes many

Re: [time-nuts] lunatic fringe time standards

2010-04-15 Thread jimlux
Bob Camp wrote: Hi The only real limit on a Johnson counter is how clever you get making sure that only one stage is a 1 and all the rest are zeros. There are *lots* of ways to take care of that, each with it's own set of trade offs. Bob Of course, if your goal is minimizing gates or

Re: [time-nuts] [OT] degausing

2010-04-15 Thread jimlux
wa1...@att.net wrote: FWIW.A good high quality compass needs to be designed based on what region of the earth you plan to use it in. The Suunto ones I have are marked with a US region code. That's because they need to compensate for the dip in the magnetic field. The south end of the

Re: [time-nuts] [OT] degausing

2010-04-15 Thread jimlux
Chuck Harris wrote: David Martindale wrote: However, I don't see how the earth's tilted field prevents a CRT from being used in both hemispheres. I can see how it might need to be realigned, since it uses permanent magnets on the yoke and their field will be influenced by the earth's local

Re: [time-nuts] [OT] degausing

2010-04-16 Thread jimlux
Chuck Harris wrote: Are they really? For some reason, every Trinitron I have ever seen has clusters of little stick on magnets placed here and there on the back of the glass envelope. The trinitron has a shadowmask. It is a grill of highly tensioned wires that are positioned just behind the

[time-nuts] venerable ICs was Re: lunatic fringe time standards

2010-04-20 Thread jimlux
Bob Camp wrote: Hi The ua723 obviously is the one destined to outlive the cockroaches. The linear power supply industry still seems to consider them state of the art. Bob Like the 555, it has a nice combination of function and predictability. It's in that good enough category.

Re: [time-nuts] GPS 1 PPS accuracy limits

2010-04-20 Thread jimlux
life speed wrote: Time Nuts; I have a customer request for a microwave frequency synthesizer with extreme accuracy requirements; 4 X 10^-11, or 0.04 PPB. Obviously this is way out of quartz oscillator territory. Is GPS 1 pulse-per-second useable, or do they need an atomic clock? Maybe they

Re: [time-nuts] oscillator choice question

2010-05-02 Thread jimlux
Hal Murray wrote: bruce.griffi...@xtra.co.nz said: If there is no electronic tuning available one can use a DDS based synthesiser to produce a corrected output frequency. However close in spurs will be problematic unless one use a couple of simple mix and divide stages or resorts to a

Re: [time-nuts] Simple PLL chips, gone ?

2010-05-04 Thread jimlux
Luis Cupido wrote: Hi, I'm looking for a relatively simple PLL chip like LMX1501 or similar. I mean, looking for a new design, that is something that is easy to source (known to be in production etc) recent/modern enough to provide a low phase noise. Is for VHF/UHF below 500MHz application

Re: [time-nuts] Simple PLL chips, gone ?

2010-05-04 Thread jimlux
Luis Cupido wrote: Hi, I'm looking for a relatively simple PLL chip like LMX1501 or similar. I mean, looking for a new design, that is something that is easy to source (known to be in production etc) recent/modern enough to provide a low phase noise. Is for VHF/UHF below 500MHz application

Re: [time-nuts] Simple PLL chips, gone ?

2010-05-04 Thread jimlux
Nick Foster wrote: If you're thinking about using a CPLD to load registers in a PLL chip, why not just implement the PLL on the CPLD? After all, if you're looking for simpler-is-better, there's not much on a dedicated PLL chip that you can't easily replicate in CPLD with some care and

Re: [time-nuts] synchronizing a large number of weakly coupled oscillators

2010-05-12 Thread jimlux
Eugen Leitl wrote: Has anyone utilized a network of locally, weakly coupled oscillator synchronization (a la http://www.projectcomputing.com/resources/sync/index.html ) for precise timekeeping purposes? There was a discussion on this list about doing something like filling a cavern with

Re: [time-nuts] synchronizing a large number of weakly coupled oscillators

2010-05-12 Thread jimlux
Bob Camp wrote: Hi The tendency of clocks to self synchronize dates back at least to the days of pendulum clocks. It may date to the era of water clocks, but if so it's undocumented. It has been observed on a wide range of modern clock designs. If you look into injection locking you'll get a

Re: [time-nuts] synchronizing a large number of weakly coupled oscillators

2010-05-12 Thread jimlux
Eugen Leitl wrote: On Wed, May 12, 2010 at 06:03:11AM -0700, jimlux wrote: Allan had a paper where he had 8 inexpensive crystals coupled with mixers and a microcontroller. I think it's called the Clever Temperature Compensated XO or something like that. Presumably, a large population

Re: [time-nuts] (no subject)

2010-05-21 Thread jimlux
Rex wrote: Sorry about the empty post -- hit the send key by accident. Ulrich's free Z38XX program works great as a monitor for the Z3805. He added some stuff to specifically support differences from a Z3801. The Z3801 programs can be used but can't support the extra satellites the 3805 can

Re: [time-nuts] Z3805 utility, Was: AW: (no subject)

2010-05-22 Thread jimlux
Mike S wrote: At 09:47 PM 5/22/2010, Robert Darlington wrote... Was there ever a standard? I always thought the RS stood for Recommended Standard, as in you *should* do the following as Recommended Standard, and is this is a standard which is recommended for use. The latest standard I've

Re: [time-nuts] Z3805 utility, Was: AW: (no subject)

2010-05-23 Thread jimlux
Robert Benward wrote: Bob Looking at al these pictures, I'm beginning to think I have a Z3801A, not a 05A. After a few hours, the unit still has not locked. It is possible the antenna is bad. I have a few more that I know are working. I also took the precaution of connecting an antenna

Re: [time-nuts] Z3805 utility, Was: AW: (no subject)

2010-05-23 Thread jimlux
Stanley Reynolds wrote: snip Dec computers / terminal servers were as I described, but many brands were different. Still have a BOB aka break out box with LEDs to indicate levels, matching transmit and receive is easy, getting the hardware flow control / signaling right was a little more

Re: [time-nuts] IRIG B

2010-05-25 Thread jimlux
Clive Green wrote: Can anyone help with a modern IRIG B chipset manufacturer I didn't know that there was such a thing, even in ancient times, much less modern. All I've seen are designs made of discretes or programmed in a microcontroller or FPGA. Are you looking for a IRIG generator or

Re: [time-nuts] IRIG B

2010-05-25 Thread jimlux
Hal Murray wrote: Can anyone help with a modern IRIG B chipset manufacturer Send or receive? The ntp package has software for both sides using PC audio cards. I've been looking for an open-source IRIG B or E reader for FPGA use. ___ time-nuts

Re: [time-nuts] IRIG B

2010-05-25 Thread jimlux
Stanley Reynolds wrote: Example of IRIG-B generator and decoder implemented in LabVIEW FPGA: http://zone.ni.com/devzone/cda/epd/p/id/3396 Thanks, I was looking for something in VHDL or Verilog... I'm not sure how well the Labview RIO, etc. stuff ports to non-Labview environments, but I'll

Re: [time-nuts] IRIG B

2010-05-25 Thread jimlux
Bob Camp wrote: Hi Audio codecs (especially monophonic ones) are pretty cheap these days. Depending on volume they can get to the sub $1 range. Even in small quantity they are below $4. That makes them a pretty tempting front end for a send / receive box. Bob i would think, given that the

Re: [time-nuts] IRIG B

2010-05-25 Thread jimlux
Hal Murray wrote: The IRIG-B decoder work I did was implemented on power systems relays disturbance recorders several years ago, then I left the company and in the meantime, they changed over to an FPGA implementation and skipped the processor altogether. Now I'm back with that same company

Re: [time-nuts] IRIG B

2010-05-25 Thread jimlux
Magnus Danielson wrote: On 05/26/2010 01:09 AM, Bob Camp wrote: Hi Like all the rest of us I'm making assumptions. I *assume* that we're talking about an implementation that will handle IRIG over audio over a fairly wide dynamic range. Well, like most cases, I'd assume it is over

Re: [time-nuts] IRIG B

2010-05-26 Thread jimlux
Bob Camp wrote: Hi Strange as it seems, *stocking* the R's and C's can be an issue. There's also placement cost. Based on some of the numbers you see, the cross over point (IC to odd value R's and C's) is amazingly low. I'm not saying any of that's right, just that it's the way a lot of

Re: [time-nuts] Flood of low end priced VNAs on FleeBay

2010-06-02 Thread jimlux
Steve Rooke wrote: Just noticed there is a flood of lower end priced ($5k $5k) VNAs on FleeBay just in case anyone is looking for one. No need to thank me, just buy me one as well :) Steve Interesting... be aware that a lot of those 8510s aren't the whole analyzer, just the display or RF

Re: [time-nuts] Flood of low end priced VNAs on FleeBay

2010-06-02 Thread jimlux
Richard (Rick) Karlquist wrote: We have a bunch of sweepers at work, and many of the them have died and can't be fixed. The only way they can be repaired is to cannibalize one to fix another, assuming they don't have the same bad module. We have given away an 8510 to a school and have others

Re: [time-nuts] Flood of low end priced VNAs on FleeBay

2010-06-02 Thread jimlux
J. Forster wrote: VNAs are very expensive toys. I have an HP 8753 and was just outbid on a 6 GHz source assembly. :(( Mine has a very complex multi-chip RF Hybrid that has a partial failure, so it only goes to 3 GHz. That's a serious problem with modern high-end microwave gear, if anything

Re: [time-nuts] OT - HP 5183A Waveform Recorder - is it worth playing with?

2010-06-02 Thread jimlux
You can, of course, now get 12 bit digitizer PCI cards for your PC. Or heck, eval boards for 12 bit ADCs that have USB interfaces.. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] A philosophy of science view on the tight pll discussion

2010-06-05 Thread jimlux
Magnus Danielson wrote: Also, modern cheap programmable TCXOs break the model as they have a hump in the phase noise due to their locked PLL, which the original model does not allow for. The autocorrelation function will be quite different. Notice how this ripples over to other locked

Re: [time-nuts] DCF77 clock with UTC display 5

2010-06-06 Thread jimlux
Giuseppe Marullo wrote: If it is, why not purchase an *analog* DCF77 synchronized clock, set it to local radio time and then just move the hands on the spindle to reflect UTC? That's what I did with my WWV clocks that only handle the US time zones. Worked just fine. Well, I could just buy a 3

Re: [time-nuts] TPLL secret reveled

2010-06-10 Thread jimlux
Ulrich Bangert wrote: The next improvement to the old fashioned pure counter was the invention of subclock interpolation schemes. A counter using this works so: After the beginning of the gate time it waits of the next zero crossing and then measures the time up to the last zero crossing

Re: [time-nuts] TPLL secret reveled

2010-06-10 Thread jimlux
Ulrich Bangert wrote: Jim, pardon if I correct you: The reciprocal counters were an intermediate thing between the counting only and the subclock interpolating ones. A reciprocal counter would notice when a frequency measurement would be too imprecise due to an arkward relationship between that

Re: [time-nuts] UTC and leap seconds

2010-06-11 Thread jimlux
Tom Van Baak wrote: Whether the answer is (a) or (b) doesn't change the fact that the earth day is a poor clock compared with other clocks now available. Besides tidal friction effects which might be hard to imagine, or lunar effects which you already know about, note that every time it rains

Re: [time-nuts] UTC and leap seconds

2010-06-11 Thread jimlux
Hal Murray wrote: iov...@inwind.it said: I was wondering, why we assume that Earth's rotation is slowing down, instead that clocks are speeding up? The quick answer is that there is a mechanism that explains why the Earth is slowing down: tidal effects. There is no corresponding way to

Re: [time-nuts] UTC and leap seconds

2010-06-11 Thread jimlux
Hal Murray wrote: jim...@earthlink.net said: The Chilean earthquake changed the angular rotation rate (or, probably more accurately, changed the direction of the axis of rotation as well) of the earth a small amount, as do most large earthquakes. Has anybody measured that? I don't think

Re: [time-nuts] UTC and leap seconds

2010-06-12 Thread jimlux
Magnus Danielson wrote: On 06/12/2010 02:33 AM, Hal Murray wrote: jim...@earthlink.net said: The Chilean earthquake changed the angular rotation rate (or, probably more accurately, changed the direction of the axis of rotation as well) of the earth a small amount, as do most large

Re: [time-nuts] UTC and leap seconds

2010-06-12 Thread jimlux
Magnus Danielson wrote: On 06/12/2010 03:36 PM, jimlux wrote: bunch o' stuff While it would be fun to know, the practical impact of such a change is very, very small, to the level of being ignored. Considering of a major event actually consisting of many hundreds of earth quakes spread over

Re: [time-nuts] Galvanic decoupling of GPS antenna

2010-06-18 Thread jimlux
Robert Benward wrote: I don't think the shield is rated for +/-250V, and I'm not sure I would want to handle RG-58 with 250V on the shield.If you do this, use triax cable and ground the outter shield, and make sure the breaker can interrupt the fault current (if the fault currrent is in

Re: [time-nuts] Galvanic decoupling of GPS antenna

2010-06-18 Thread jimlux
Robert Benward wrote: Rated for 1400V from CENTER conductor to shield, not shield to the outside. If you choose to use RG-58 with 250V on the shield then you will need to put the entire cable inside conduit. It is not acceptable to have any type of exposed mounting. Bob Yeah... I've been

Re: [time-nuts] AVAR Femtoseconds

2010-06-20 Thread jimlux
Robert Benward wrote: Bob Boy, you guys are really making me read a lot. I'm digesting Wiki right now. I see tau, but does identifying a tau of 1E-14 allow you to say you are locked to 10fs? The smallest tau I've seen in my E1938 collection is 1E-1. Bob tau is the time over which the

Re: [time-nuts] EFC tracking

2010-06-26 Thread jimlux
J.D. Bakker wrote: I wonder if anyone has done something like this before and could share their experiences. The general principle should work. However, as you're interested in slow changes, there are some error sources that might be unacceptable, including the drift of (differential)

Re: [time-nuts] EFC tracking

2010-06-26 Thread jimlux
Steve Rooke wrote: The eval board for the part may have a computer interface built into it. So I need to locate this if possible, any pointer please? Go to Analog Devices website (http://www.analog.com/) and find your ADC.. typically there's an eval board with a USB interface available.

Re: [time-nuts] EFC tracking

2010-06-26 Thread jimlux
Didier Juges wrote: Steve, You may want to check the Analog Devices MiniKit for ADuC702x-series. http://www.google.com/search?q=Analog+Devices+MiniKit+for+ADuC702x-series This kit includes a 24 bit ADC and integrated ARM processor in a small PWB with all the tools and sample code to do what

Re: [time-nuts] EFC tracking

2010-06-26 Thread jimlux
Didier Juges wrote: I can only guess at what a sound card with linearity specs approaching those of the AD kit would cost, and it's still AC coupled, and as Poul pointed out, has no long term stability spec. This *is* an issue.. the audio ADCs have great performance in the sub 1 second sort

Re: [time-nuts] EFC tracking

2010-06-26 Thread jimlux
Didier Juges wrote: I am not sure how to translate the IMD specs into integral or differential non-linearity, but from what I have seen, IMD specs are not significantly better for 24 bit sound cards than for the older high-end 16 bit models, when high-end 16 bit models were available. Noise

Re: [time-nuts] Datum TS-2100 firmware updating

2010-06-28 Thread jimlux
erniepe...@aol.com wrote: HI Julien, Do you have a detailed info, docu about the TrueTime XL-DC?? I have 2ea of this unit and one is not going to lock... Any experience or help appreciated. Rgds Ernie. There's a fair amount of info on the XL-DC on the web. I assume your problem is

Re: [time-nuts] yet another GPSDO design, or so

2010-06-29 Thread jimlux
Bruce Griffiths wrote: Attila Kinali wrote: Moin, On Sat, 26 Jun 2010 21:14:02 EDT ewkeh...@aol.com wrote: What you want is basically a Shera Board. That design has been around for quite some time and has served me very well. Yes. The Shera Board and similar designs serve as an

Re: [time-nuts] yet another GPSDO design, or so

2010-06-29 Thread jimlux
Hal Murray wrote: or with a pair of current output DACs and a resistive divider/summer so you have a high order and low order voltage. If it were that simple, the manufacturers would package it up into a single chip. :) And they do... hence delta sigma designs.. Back in the good old days

Re: [time-nuts] Lightning strikes vs GPS antennas

2010-07-04 Thread jimlux
Michael Baker wrote: Time-Nutters-- The 5-year Flash Density Map of the USA provided by the National Weather Service indicates that my county here in N. Central Florida experiences 16 and up strikes/sq-km/year. http://www.weather.gov/os/lightning/images/map.pdf Experience bears this out...

Re: [time-nuts] Nuts and Phoolery

2010-07-05 Thread jimlux
Steve Rooke wrote: On 5 July 2010 06:10, J. Forster j...@quik.com wrote: Why stop there? How about buying Russian Hydrogen MASERs and putting them in hand-rubbed old growth teak boxes and selling them for $995,000? They are pulling out 14,500 y/o kauri trees (hard wood) out of peat bogs over

Re: [time-nuts] GPS Common View

2010-07-07 Thread jimlux
Bob Camp wrote: Hi I just got through poking at a couple of TBolts with Lady Heather. It appears that you can indeed get the hardware and software to put the TBolt into single satellite mode. That may enable a pretty simple GPS common view setup. One way to do it: Somebody picks a set of

Re: [time-nuts] GPS Common View

2010-07-07 Thread jimlux
Bob Camp wrote: Hi From a quick look it's not real clear how you would go about extracting time from the software suite. It's certainly useful for navigation though. A secondary gotcha is that the TBolt likely has some internal issues that distort the data a bit. Running a TBolt on both

Re: [time-nuts] Loran-C Anthorn

2010-07-12 Thread jimlux
EB4APL wrote: A word of caution here: Don't trust Google maps coordinates for any technical / serious work, they can have errors in the 100´s meter class. And also don't use the copyright date of the maps and images as a time reference, they normally are older than that. If you live in an

[time-nuts] rapid startup GPSDO

2010-07-14 Thread jimlux
Is there some (inexpensive) GPSDO that has a time from power on in an unknown location to reasonably stable in the 5 minute category? Frequency accuracy in the 1E-9 range would be fine. A regular old GPS has a Time to First Fix well under that, and it should be cranking out 1pps pulses with

Re: [time-nuts] rapid startup GPSDO

2010-07-14 Thread jimlux
Luis Cupido wrote: Jim, The implementation I've done on reflock II (on a MAXII CPLD form Altera http://www.qsl.net/ct1dmk/reflock.html ) Had fast aqs time in mind(*). It captures in few 1pps pulses and could stabilize to about 1% of dac range in quite less then 60s. How slower you need it to

Re: [time-nuts] A different timenuts interest

2010-07-21 Thread jimlux
J. Forster wrote: The problem is straight forward, except for sensing the position of the pendulum so the impulse is applied at the correct phase. There must be a bunch of published designs, but if I were to try it, I'd use something optical or capacitive. For optical, I'd put a annular ring

Re: [time-nuts] A different timenuts interest

2010-07-22 Thread jimlux
Eugen Leitl wrote: On Wed, Jul 21, 2010 at 10:40:48PM -0400, Bob Bownes wrote: Silly me, I just realized you need to compensate for the change in length with temperature. You could use an Invar wire. Some insight from a friend (a proto-timenut) who was thinking about building a 1ppm free

Re: [time-nuts] A different timenuts interest

2010-07-22 Thread jimlux
J. Forster wrote: E A Foucalt Pendulum is not about time! It's about motion in inertial space. are they not the same, underneath it all? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] Basic question regarding comparing two frequencies

2010-07-24 Thread jimlux
J. Forster wrote: .. more generic interface. ?? The vast majority of professional test equipment has GPIB. Virtually anything else is an also ran. FWIW, -John these days, ethernet and USB are becoming more popular. My own preference is Ethernet and I long for the day when I can ditch

Re: [time-nuts] Basic question regarding comparing two frequencies

2010-07-24 Thread jimlux
J. Forster wrote: I very much doubt that the majority on this list have major govenmental or corporate funding and shop from the new Agilent catalog that just came in the mail. As a result, I'd guess almost all the commercial test gear in the posession of listers is from 1970 to 2000. That says

Re: [time-nuts] Basic question regarding comparing two frequencies

2010-07-25 Thread jimlux
J. Forster wrote: Probably yes. There are also a number of lower cost instruments (just above consumer grade)like HF-VHF VNAs that implement much of the smarts in a PC on the market. As to high end instruments w/ USB or Ethernet, I'm not so sure. The USA is doing less and less hardware

Re: [time-nuts] Basic question regarding comparing two frequencies

2010-07-25 Thread jimlux
Hal Murray wrote: jim...@earthlink.net said: But over the next few years, I suspect you'll see more and more of it coming onto the surplus market. My fond hope is that my daughter will be able to capitalize on it. A friend had a fancy scope with an Etherenet. It got infected with the

Re: [time-nuts] Basic question regarding comparing two frequencies

2010-07-25 Thread jimlux
Steve Rooke wrote: That seems to indicate these devices are running a version of embedded Windows for them to get infected by a virus and I wonder why they need such a sledgehammer internally. Steve PS. sorry for top-posting but that's the only way I can reply at the moment (basic HTML Gmail).

[time-nuts] Test gear with embedded PCs Re: Basic

2010-07-25 Thread jimlux
David C. Partridge wrote: Jim, It might appear on the 2nd user market sooner, but the odds are you won't be able to either repair it or calibrate it as the manufacturer will have been the only supplier of either of these services, and no service manuals will exist. But is this any different

Re: [time-nuts] Regulating a pendulum clock

2010-08-09 Thread jimlux
Bob Holmstrom wrote: Food for thought. I find it interesting that no one has suggested alternatives to improving the performance of a pendulum clock other than controlling it with a higher performance clock. If the goal is a better clock why not attempt to understand the source of the

Re: [time-nuts] Regulating a pendulum clock

2010-08-09 Thread jimlux
Bob Camp wrote: Hi For that matter, how hard is it to put it in a vacuum with temperature control? Gets two big issues out of the way pretty fast. We certainly buy crystal oscillators that are heated and enclosed in pressure tight containers (not quite the same as vacuum, but close). Bob

Re: [time-nuts] Regulating a pendulum clock

2010-08-09 Thread jimlux
Ian Sheffield wrote: What happens when the rope breaks? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: 09 August 2010 19:10 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Regulating

Re: [time-nuts] Regulating a pendulum clock

2010-08-09 Thread jimlux
Javier Herrero wrote: Not so simple... you should move it around in order to balance the gravity force vector :) Regards, Javier two large masses rotating around the pendulum, one synchronized with the sun, one sync'd with the moon. Having just looked up the orrery stuff, a suitable

Re: [time-nuts] Regulating a pendulum clock

2010-08-09 Thread jimlux
Bruce Griffiths wrote: Advisable given the required mass will probably be in the 10-100 ton range. Bruce J. L. Trantham, M. D. wrote: Personally, I would get out of the way. : ) Joe Wait a minute.. is it that big? or is it much, much bigger.. Inverse square is involved. The moon's mass

Re: [time-nuts] Regulating a pendulum clock

2010-08-09 Thread jimlux
I screwed up by a factor of a million.. jimlux wrote: Bruce Griffiths wrote: Advisable given the required mass will probably be in the 10-100 ton range. Bruce J. L. Trantham, M. D. wrote: Personally, I would get out of the way. : ) Joe Wait a minute.. is it that big? or is it much

Re: [time-nuts] Remove Pictic boards from envelopes

2010-08-10 Thread jimlux
Alan Melia wrote: Pencil?? only us oldies know what that is... it is surprising the lead pencil hasn't been banned under RoHS :-)) Alan G3NYK I don't know that lead (as in the element) has ever been used in pencils.. I read a fascinating book on the history of the pencil a few years

Re: [time-nuts] Remove Pictic boards from envelopes

2010-08-10 Thread jimlux
Alan Melia wrote: Hi Jim ...being ironic...see the smiley Alan sorry... I was lubing my slip-stick with a pencil and didn't catch it.grin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] Simulation

2010-08-14 Thread jimlux
Bob Camp wrote: Hi Simply a few stories I thought I would share. Simulate design. Use manufacturer's published models. Build design. Note differences. Call manufacturer. Answer - switched die three years ago, Ft is now much better ( now 3x old parts ). Odd they never mentioned that to

Re: [time-nuts] Simulation

2010-08-14 Thread jimlux
J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John Or, has their back against the wall and can't do it any other way. How is

Re: [time-nuts] Simulation

2010-08-14 Thread jimlux
Hal Murray wrote: Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume

Re: [time-nuts] Fwd: Fwd: PicTic Data

2010-08-15 Thread jimlux
Steve Rooke wrote: Stanley and Nigel, I have received the go ahead to distribute the Small DMTD project files from Bill. It is in the form of a 500k zip so how do we want to play this? For a start, Gmail will not let me send .exe files, even though they are inside a zip file and I'm not putting

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