Re: [time-nuts] State of the art of crystal oscillator measurements

Hi The gotcha is that you don’t *have* to have a 50 ohm system. An output stage with a narrow band tuned tank is one example of a very “not 50 ohms” system. There is also a whole debate around the “is 50 ohm source into 50 ohm load really 25 ohms”. That will give you a 3 db delta to bet

Re: [time-nuts] Low cost SDR suitable for phase noise measurement?

Hi Just to clarify: You are looking for a way to digitize the output(s) of the mixer(s) in a DMTD. The “target signal” is in the 1 to 10 Hz range. Is that correct or are you looking for something to use instead of a DMTD? Bob > On Aug 11, 2016, at 3:29 PM, Bob Stewart

Re: [time-nuts] Shera revisted

Hi To your earlier point, there are a number of fairly low cost boards with Zynq’s on them. They aren’t into the $5 range, but they are not that much more than one of the Beagle boards. Bob > On Aug 10, 2016, at 11:18 PM, Chris Albertson > wrote: > > Thanks

Re: [time-nuts] Questions on Nortel Trimble NTBW50AA GPSTM

Hi You can get a very good industrial 24V supply for < $40 (and maybe < $20) brand new from distribution. Comes with a 3 year warranty and has all the various protection things you would want on a supply. My claim is that you will always have 12V, 24V and 48V “stuff” running around. Having a

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

Hi An even more significant question: Is it worth doing? More or less: Do you know the delay numbers for your antenna? Do you know the delay numbers for your GPS module? How close can you *guess* the length of the cable? Knowing absolutely nothing at all about your setup, I’ll guess the

Re: [time-nuts] GPS antenna selection - lightning

Hi We tend to look at all this lighting / EMP stuff very much as a “get to the ground” sort of thing. For whatever reason the whole thought process stops once we get to a coper weld rod driven however far into the dirt. If you try to operate a vertical antenna against that same rod in the

Re: [time-nuts] Oscillator Phase Noise: A 50-Year Review

Hi I have seen several other attempts in the past few decades to write “history” papers in the context of IEEE proceedings. They (unfortunately) always seem to turn into a set of personal recollections rather than a proper history. It would be *very* useful to have a complete trace of who

Re: [time-nuts] Looking to find an antenna for a TrueTime XL-DC

Hi Add in variables like supply voltage, tuning approach, signal levels, and gain …. There are a lot of things you need to match up to get a downconverter going with an old style GPS. Once you do, you then likely have a unit that has GPS epoch roll over issues. It may have other firmware

Re: [time-nuts] Austron 2010B (disciplined OCXO) square wave conversion

Hi > On Aug 6, 2016, at 3:00 AM, Ruslan Nabioullin wrote: > > Hi, I recently bought an Austron 2010B, a disciplined OCXO standard with > adjustable disciplining parameters, for use as a clean-up oscillator and a > decent fallback to my Ball MRT-H, a rubidium standard.

Re: [time-nuts] GPS antenna selection — lightning

Hi Ummm ….. It’s a *lot* more fun to focus on the 0.001% case :) Bob > On Aug 5, 2016, at 9:31 PM, Chris Albertson wrote: > > You guys, well some of you are mixing to things > > 1) the building code requirement to ground an antenna is for the protection > of the

Re: [time-nuts] Using the HP 58503a to correct your PC clock

Hi Ok, here I am at home. My network gear is simple. Cisco low end switches and Gig-E wires. No fancy Sync-E. No 1588 stamps from the switches. Data comes in via a cable modem. The beast has highly asymmetric send and receive transit times. They both wander around in response to their own

Re: [time-nuts] Best choice for GPS active antenna voltage?

Hi If you are doing your own antenna supply: 1) Make very sure it is current limited at some rational level (say 150 ma). A resettable fuse may be fine for this. 2) Make sure you have some way to detect a short on the antenna. 3) Put in some sort of surge suppression. A microwave compatible

Re: [time-nuts] GPS antenna selection — lightning

o — even when cables to the “outside” were > disconnected, and AC mains power was shut off at the main circuit breaker > box. After implementing comprehensive surge protection, we have had zero > damage over the last 12 years. > > — Eric > >> On 2016 Aug 04, at 19:46 , B

Re: [time-nuts] GPS antenna selection

Hi > On Aug 4, 2016, at 7:26 PM, Herbert Poetzl <herb...@13thfloor.at> wrote: > > On Thu, Aug 04, 2016 at 06:26:28PM -0400, Bob Camp wrote: >> Hi > > Hey Bob! > >>> On Aug 4, 2016, at 5:29 PM, Herbert Poetzl <herb...@13thfloor.at> wrote: >

Re: [time-nuts] GPS antenna selection

Hi > On Aug 4, 2016, at 5:29 PM, Herbert Poetzl wrote: > > > Dear fellow time-nuts! > > I'm currently investigating my options regarding > GPS antennae (of course for time related purposes) > and I'm really confused by the variety they come > in ... (my apologies in

Re: [time-nuts] Effect of EFC noise on phase noise

Hi Picking some random 10811-ish numbers: 10 MHz output 5V EFC range 1.6 ppm total EFC range 10 Hz offset from carrier If you put in 300 nv of noise, in a 1Hz bandwidth, you get around -146 dbc of phase noise. Your OCXO would be doing very well at 10 MHz to run -135 dbc phase noise at 10 Hz.

Re: [time-nuts] Using the HP 58503a to correct your PC clock

Hi How big a correction are you seeing? Is the correction consistent? Bob > On Aug 2, 2016, at 11:13 PM, Ron Ott wrote: > > This has probably been covered in the past, but is there a way correct or > control a PC (Windows 7) clock with the HP 58503A GPS receiver? I

Re: [time-nuts] Effect of EFC noise on phase noise

Hi Ultimately the EFC signal gets to one or more varicap diodes. It likely goes through a bias or attenuator network to get there. Playing with the resistors in the network allows the manufacturer to produce parts with consistent EFC properties. The pinout of your standard OCXO and it’s single

Re: [time-nuts] Effect of EFC noise on phase noise

se at a circuit point with a cap is always kT/c > > On Monday, 1 August 2016, Bob Camp <kb...@n1k.org> wrote: > >> Hi >> >> If you wire up all the possible circuits and check them all out … the >> answer is that big C / small R wins. Big R gets you into re

Re: [time-nuts] Effect of EFC noise on phase noise

Hi If you are in the region that a low noise reference will apply to a low deviation precision standard, you are deep into “small angle” territory. The higher order stuff simply does not apply. Rotate the spectrum by 1/f (FM -> PM) and calculate the level at 1 Hz …..end of story. If when you

Re: [time-nuts] Effect of EFC noise on phase noise

Hi If you wire up all the possible circuits and check them all out … the answer is that big C / small R wins. Big R gets you into resistor noise issues and stray pickup. Bob > On Aug 1, 2016, at 4:16 PM, David wrote: > > This duplicates the problems encountered when

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

HI You very much are not *done* when you get your point at a million seconds. That’s just where you get to *start* …. Since you are talking about nearly two weeks per sample, there are a *lot* of things that could happen. If your loop needs ten samples to do much with, it will be 4 months

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

Hi The issue with any of these approaches is how long it will take to converge. If I start with a pps that is good to 10 ns and my goal is 10 ns or 10 ppb, I’m there in a second. If I start with a serial string that is good to 10ms and my goal is 10 ppb, I’m waiting for a million seconds per

Re: [time-nuts] Effect of EFC noise on phase noise

Hi ….. until you discover that you picked the *wrong* capacitor manufacturer and you have more noise from leakage in the cap than you did to start out with :) In general “big C and small R” is the better solution than “big R and small C”. The pesky part is that with electrolytic caps, the

Re: [time-nuts] Effect of EFC noise on phase noise

Hi It’s just very standard FM modulation math. The only gotcha is the (often unknown) bandwidth of the EFC port. Even on a precision OCXO, it might be <10 Hz, it might be over a KHz …. The trap many fall into is the “small angle” restriction. You can get into modulation indexes that will get

Re: [time-nuts] Q/noise of Earth as an oscillator

Hi > On Jul 31, 2016, at 8:19 PM, Hal Murray wrote: > > > t...@radio.sent.com said: >> So loss effects frequency in one situation and amplitude in the other. How >> can Q relate to both situations? > > It's energy loss in both cases. > > Is there a term other than Q

Re: [time-nuts] Commercial software defined radio for clock metrology

au will overestimate stability at > the tau? If using averaged data, would it be “less lying” to multiply the > ADEV by the sqrt of the length of the averaging window? > > I’d appreciate your thoughts on the subject, > > Kevin > >> On Jul 29, 2016, at 6:51 PM, Bo

Re: [time-nuts] Commercial software defined radio for clock metrology

ond window. Is your point that >> averaging samples that are more frequent than the tau will overestimate >> stability at the tau? If using averaged data, would it be “less lying” to >> multiply the ADEV by the sqrt of the length of the averaging window? >> >> I’d apprec

Re: [time-nuts] Commercial software defined radio for clock metrology

HI Keep in mind that if you apply pre-filtering, an ADEV plot is lying to you …. Bob > On Jul 29, 2016, at 6:58 PM, Kevin Rosenberg wrote: > > Jeff, > > Thanks for your very useful paper Oscillator Metrology with SDRs[1]. I > created a C++ program and checked residuals

Re: [time-nuts] Very Accurate Delta Time RF Pulse Measurements

Hi If you have a need to do < 1 ns with a counter approach, the counter will need to have a GHz clock in it. If you want to use an MCU counter, it will need to have a GHz level clock routed to it. You are unlikely to find an MCU that will do that. An FPGA can get you to 1.25 ns with direct

Re: [time-nuts] Q/noise of Earth as an oscillator

Hi > On Jul 27, 2016, at 12:57 PM, Ron Ott wrote: > > There might be two Qs: one relating to the axil rotation and another > concerning the volume behavior of the earth as a giant bowl of Jello. But > you'd have to figure out how to really slam the planet to excite the

Re: [time-nuts] GPS receiver time message offsets to 1PPS (updated)

Hi So everything is inside a 10 ms sdev except: UBLOX LEA-6T NMEA at 11.1 ms (Binary is much better) Adafruit Ultimate at 39.8 ms Neither one of those are really surprising. NMEA is not the best thing on uBlox. The specs on the Adafruit part have never made much sense for timing. Somebody was

Re: [time-nuts] [LEAPSECS] Leap second to be introduced at midnight UTC December 31 this year

Hi In these days of computers trading with computers, the whole issue of “who did what when” can result in major money trading hands. I’m sure that at some point the financial markets will have to deal with light speed issues and geography if they have not already. Bob > On Jul 25, 2016,

Re: [time-nuts] Symmetricom Power On Counter

Hi Maybe it only has a 20 year life if you power it up 50% of the time :) Somehow I doubt that it only has a 10 year “power on” life. Bob > On Jul 25, 2016, at 3:55 PM, Skip Withrow wrote: > > Hello Time-Nuts, > > I just ran a Symmetricom X72 for 10 days to check the

Re: [time-nuts] [LEAPSECS] Leap second to be introduced at midnight UTC December 31 this year

Hi > On Jul 25, 2016, at 10:21 AM, Martin Burnicki <martin.burni...@burnicki.net> > wrote: > > Bob, > > Bob Camp wrote: >> Hi >> >> The practical problem with any change to leap seconds is transition from >> what we have >> to the “new

Re: [time-nuts] The home time-lab

Hi If you go back far enough in time …. there is another alternative: Big rectifier bank, turning AC into DC, often off of multiple phases or sources. Big DC motor running into a fairly large flywheel. AC generator (or in some cases DC generators) running off of the

Re: [time-nuts] NCOCXO anyone?

Hi A typical double oven design runs about 10 mw or so in the circuitry in the inner oven. The “stuff” inside the outer oven likely doubles that number. The rest of the circuit is put outside the outer oven to reduce heat rise. There could be another 40 mw in that part of the circuit.

Re: [time-nuts] NIST UT1 NTP server results

> On Jul 23, 2016, at 11:52 AM, Steve Allen <s...@ucolick.org> wrote: > > On Sat 2016-07-23T10:10:07 -0400, Bob Camp hath writ: >> Ok, so now what we need are at least 5 other public UT1 NTP servers so you >> can properly >> synch up to a set of them. >

Re: [time-nuts] NIST UT1 NTP server results

Hi Ok, so now what we need are at least 5 other public UT1 NTP servers so you can properly synch up to a set of them. Bob > On Jul 23, 2016, at 8:47 AM, Mike Cook wrote: > > As I suspected NTP client handles the UT1 data ok if there is just that > server configured. >

Re: [time-nuts] NIST UT1 NTP server results

Hi There have been a number of “unusual” NTP servers running over the years. The whole “how do we handle leap seconds” thing resulted in a lot of variation. Simple answer is still the same: Only connect to servers that you have checked out. Bob > On Jul 22, 2016, at 6:23 PM, John Hawkinson

Re: [time-nuts] [LEAPSECS] Leap second to be introduced at midnight UTC December 31 this year

Hi The practical problem with any change to leap seconds is transition from what we have to the “new system”. Anything other than dropping them altogether involves a *lot* of coordination. You pretty much have to pick a date and bring everything onto the new standard then. For testing

Re: [time-nuts] NCOCXO anyone?

Hi Ideally a phase micro stepper would have an ADEV floor that is lower than anything you would run through it. That way the ADEV in would be the same as the ADEV out. Since there are things out there that are lower ADEV than an OCXO, that’s not a good thing to put in the middle of the beast.

Re: [time-nuts] NCOCXO anyone?

Hi > On Jul 21, 2016, at 7:17 PM, Poul-Henning Kamp wrote: > > > In message <4763643485B04450A76F7C04BA8CFB63@pc52>, "Tom Van Baak" writes: > >> There are highly-prized commercial instruments that do this. But >> no amateur has tried yet. > > It would be more

Re: [time-nuts] LSEM (Leap Second Every Month)

Hi A leap millisecond …. there’s an idea to explain to grandma. If you accept the idea that we need a leap second ever year or three, it’s not going to be a millisecond. Something messy would be required if you went below 100 ms. 100 ms would (barely) accommodate a “once a year” leap

Re: [time-nuts] Leap second to be introduced at midnight UTC December 31 this year

Hi If you have a “zero option” then nothing ever gets tested. It always sits at zero and gets ignored. If you dither back and forth +/- 1 second, it’s tested every month. The faulty system that does not follow the signal gets spotted and fixed. Bob > On Jul 21, 2016, at 3:03 PM, Tom Holmes

Re: [time-nuts] GPS message jitter (preliminary results)

HI > On Jul 20, 2016, at 7:51 PM, Mark Sims wrote: > > I added the ability of Lady Heather to calculate the time offset of the > timing message from "wall clock" time. It calculates the difference between > the system clock time to the time that the (end of) the timing

Re: [time-nuts] How does sawtooth compensation work?

Hi > On Jul 19, 2016, at 7:41 PM, Michael wrote: > > Thanks Tom, Bob, and Mark (wrote my response to Tom first, but didn't hit > send)! > > I've actually been collecting some *ancient* dual-frequency geodetic gear to > play with, some of which have external clock

Re: [time-nuts] How does sawtooth compensation work?

Hi The only way to be sure on either the sawtooth or the cable delay is to try it and see. I have observed it being put in backwards (in both cases) more often than I have seen it put in the right way around. Bob > On Jul 19, 2016, at 12:47 PM, Mark Sims wrote: > >

Re: [time-nuts] How does sawtooth compensation work?

Hi The reason people do not routinely jump to number 3 on the list is cost. The only new GPS modules that I am aware of in category 3 are well over $2K each. That is in comparison to Mark’s favorite $5 modules. You can buy eBay surplus older versions of the fancy boards. So far I have not seen

Re: [time-nuts] How does sawtooth compensation work?

Hi On the sub-set of receivers that send you the sawtooth correction *after* (as in 200 ms after) the PPS …. the delay line correction thing does not work very well. Also in a “strict time nuts” sense, you can only delay the edge. If the sawtooth says the edge was late, you can never get it

Re: [time-nuts] How does sawtooth compensation work?

Hi The sawtooth process “picks” the closest clock edge and spits out the PPS based on it. If the internal TCXO is off of a point that divides to 1Hz, the edge guess changes fairly often and you can average it out. A drifting TCXO will (effectively) never be at a modulo 1 Hz frequency long

Re: [time-nuts] GPS message jitter (preliminary results)

Hi Very nice data !! Hmmm….. software averaging against the MCU (or FPGA) clock source … NTP seems to get some pretty good results down into the single digit ms (or lower) doing that based on some equally jittery inputs. Looking at the data by eyeball (maybe not the best way): A 10 to 30

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

Hi > On Jul 18, 2016, at 12:19 PM, David J Taylor > wrote: > > I suppose it is one of those cases where, the GPS designers decided you > shouldn't ever use the serial data for sub-second timing, and consequently > spent no effort on serial latency and jitter. >

Re: [time-nuts] GPS Antenna

Hi > On Jul 17, 2016, at 2:35 AM, David J Taylor > wrote: > > The GPS Antenna Micropulse Z1001 appears to be what is now designated > GPS-TMG-26N > > Lester B Veenstra MØYCM K1YCM W8YCM > les...@veenstras.com > __ > > Why

Re: [time-nuts] GPS for Nixie Clock

Hi The gotcha is that it’s the sum of the radiation arriving in the vicinity of the gas. Supplying a bit can flood small variations, but they still are present. You are trying to get what is essentially a neon bulb to trigger accurately to a very tight budget. There is a lot of prior art on

Re: [time-nuts] GPS for Nixie Clock

Hi Since we have moved into synchronizing this stuff at the nanosecond level (maybe we are even lower than that by now ..), simply getting a wide band enough signal off of a Nixe socket is going to be “interesting”. An array of picosecond photo diodes on each tube may be the only way to go. How

Re: [time-nuts] GPS for Nixie Clock

Hi > On Jul 15, 2016, at 11:40 PM, jimlux <jim...@earthlink.net> wrote: > > On 7/15/16 5:25 PM, Bob Camp wrote: >> Hi >> >> You can do a pretty good job with a high speed photo diode. They are not >> cheap, but >> you can get fast ones if your

Re: [time-nuts] GPS for Nixie Clock

) 518-1389 > > On 7/15/2016 8:55 PM, Bob Camp wrote: >> Hi >> >> As this is going, it’s not a clock at all. It’s a GPSDO with a Nixie display >> on it >> and now with IRIG timing output. >> >> Do we put an Rb in it or go straight to a Cesium? &g

Re: [time-nuts] GPS for Nixie Clock

Hi As this is going, it’s not a clock at all. It’s a GPSDO with a Nixie display on it and now with IRIG timing output. Do we put an Rb in it or go straight to a Cesium? Bob > On Jul 15, 2016, at 9:38 PM, Clay Autery wrote: > > I, for one, will be following your

Re: [time-nuts] GPS for Nixie Clock

> > > On Fri, Jul 15, 2016 at 3:53 PM, John Swenson <johnswens...@comcast.net> > wrote: >> Yep, that is theory. The fun part is going to be getting the right edge for >> the new PPS. Half the time it will the one before the PPS from the GPS and >> half the time i

Re: [time-nuts] GPS for Nixie Clock

which is which to align it to the new LO. > > John S. > > > On 7/15/2016 3:17 PM, Bob Camp wrote: >> Hi >> >> If you are going to go “full boat” then you probably should get the sawtooth >> correction out of >> the GPS and feed that into your control loo

Re: [time-nuts] GPS for Nixie Clock

Hi >From what I have seen, both uBlox and Furuno are very consistent in their serial timing. I’ve looked at a lot of modules, but those two come to mind pretty quick. Bob > On Jul 15, 2016, at 4:50 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> Well, if you

Re: [time-nuts] GPS for Nixie Clock

y will do an FPGA controlled PLL for the fun of it (I have > done that before). > > John S. > > On 7/15/2016 9:54 AM, Bob Camp wrote: >> Hi >> >> >> >>> On Jul 15, 2016, at 9:44 AM, David J Taylor <david-tay...@blueyonder.co.uk> >>

Re: [time-nuts] HP5370 power supply measurements

Hi Back when these pieces of gear were being made “new”, HP Spokane had a “fan silencer machine”. They used a strobe and a microphone to identify imbalanced blades and then took chunks out of them. They *claimed* it made the fans significantly less noisy….Watching it in action on a noisy

Re: [time-nuts] GPS for Nixie Clock

Hi As a single pulse flash of light you can “detect” very narrow pulses. When you start trying to decide “which one came first?” and *resolve* visual information, things slow down quite a bit. You can play a game to see how well people do. With most groups and most “targets”, anything under

Re: [time-nuts] GPS for Nixie Clock

the number, it’s not likely to change. Bob > On Jul 15, 2016, at 2:23 PM, Gary E. Miller <g...@rellim.com> wrote: > > Yo Bob! > > On Fri, 15 Jul 2016 12:54:43 -0400 > Bob Camp <kb...@n1k.org> wrote: > >> To get a time resolution of 10 ms (yes 10X 1 ms), you d

Re: [time-nuts] GPS for Nixie Clock

Hi > On Jul 15, 2016, at 9:44 AM, David J Taylor > wrote: > > Hi > > Ok, I guess we need to go into this again: > > All of the output signals generated by one of these cheap GPS modules > come from the internal TCXO on the module. All the signals. > >

Re: [time-nuts] GPS for Nixie Clock

Hi Ok, I guess we need to go into this again: All of the output signals generated by one of these cheap GPS modules come from the internal TCXO on the module. All the signals. None of the TCXO’s on any of these modules are tuned to match the GPS. None of them, zero, not any.

Re: [time-nuts] OXCO Spurious Output at Line Frequencies

Hi ummm …… errr ….. yes. If you mount the OCXO that drives an 800 MHz FM narrowband transmitter in the middle of a wall panel on the rack, you *can* measure the rotation speed of the blowers. That’s not a guess, that’s empirical knowledge :) Bob > On Jul 12, 2016, at 8:24 PM, Hal Murray

Re: [time-nuts] OXCO Spurious Output at Line Frequencies

needed a test site on the far side of the Moon :-)) > Alan > G3NYK > > - Original Message - From: "Bob Camp" <kb...@n1k.org> > To: "Discussion of precise time and frequency measurement" > <time-nuts@febo.com> > Sent: Tuesday, July 12

Re: [time-nuts] OXCO Spurious Output at Line Frequencies

Hi The “practical” solution often is to ship it to an office of the same company that happens to have 60 Hz power. The spur moves to 60 / 120 / 180 and they move on with their evaluation. I have also played the “let’s do it with batteries" approach. Screen rooms were of little benefit.

Re: [time-nuts] GPS for Nixie Clock

Hi The T version makes it easy to get at the sawtooth correction on the pps. That lets you go from 10’s of ns on the pps to below 1 ns. All of that is a bit beyond the response speed of a Nixie tube.:). It also takes an MCU to work out what’s going on and some way to incorporate the correction

Re: [time-nuts] GPS for Nixie Clock

Hi For $15 to $45 a number of places will sell you a uBlox receiver card that runs off of 5V and has an internal antenna. They are quite sensitive and have a timing output. They are plenty good enough for what you are trying to do. The practical issue is getting good enough GPS signals at an

Re: [time-nuts] Good GPSDO on eBay?

Hi The EEVB guys have been going around on these GPSDO’s for about a year now. Lots of people have tried to get refunds on them. Pretty much every trick in the book (replacement is in the mail …. need one more piece of information from you … shipping clerk in the hospital with bubonic plague …)

Re: [time-nuts] GPS disciplined Mars clock

Hi …. but what time is it on Titan :) Bob > On Jul 9, 2016, at 6:35 PM, Mark Sims wrote: > > I just added code to Lady Heather to calculate time in Terrestrial Time (TT) > and Geocentric Terrestrial Time (TCG). The difference is basically the time > dilation

Re: [time-nuts] GPS disciplined Mars clock

Hi Obviously time for a Kickstarter campaign to put a set of observatories on Mars …. Bob > On Jul 9, 2016, at 5:59 PM, jimlux wrote: > > On 7/9/16 1:40 PM, Joe Fitzgerald wrote: >> >> >> On 7/9/2016 3:00 PM, jimlux wrote: >>> >>> TAI my friend, TAI... >>> >> Hmm,

Re: [time-nuts] Does doubling a frequency alter the original ADEV of the frequency?

Hi The simple answer is that most doublers that are ok for phase noise will not degrade ADEV. The issues with ADEV come when your doubler is out in a changing environment and your oscillator is not ( = it’s an OCXO). The answer to that problem is pretty simple if you have an issue … ovenize

Re: [time-nuts] GPS disciplined Mars clock

Hi You haven’t even scratched the surface yet …. What time is it on each of the moons? :) Bob > On Jul 9, 2016, at 12:36 PM, Mike Cook wrote: > > Calculating the local planetary time is fine for solid objects with an > accepted (or proposed) prime meridian , but I don’t

Re: [time-nuts] The home time-lab

Hi Yes indeed they do run a bit warm. You need a mounting location that gets them out of the way. Having them somewhere you can bump into them …. not good at all. The newer “toroid” designs are a bit quieter than the older versions. Bob > On Jul 9, 2016, at 2:41 AM, Rob Sherwood.

Re: [time-nuts] The home time-lab

Hi If you try this, be very careful with the voltage at the junction of the L and the C. Bob > On Jul 8, 2016, at 9:52 PM, David wrote: > > I wonder how well a pair of high voltage transformers wired back to > back with a 60 Hz series resonate LC circuit between them

Re: [time-nuts] The home time-lab

Hi A 5335 / 5334 generation counter will spot a 30 ns blip. A modern MCU demo board probably can to the same sort of thing. The cost of another (cheap) couple of counters is probably less than mucking around with power line monitors and giant banks of batteries. The most likely output of a

Re: [time-nuts] The home time-lab

Hi Have you been through the full alignment process on one or both of the 5370’s ? They are as much an analog beast as they are digital. They *do* drift out of calibration / alignment / adjustment. When they go it’s usually not all of a sudden. They just gradually get worse and worse as the

Re: [time-nuts] The home time-lab

Hi As has been mentioned a few times before …. the best approach is to run batteries to supply the gear in question off of DC power. Running everything off of it’s own battery may not be practical if you have gear that is looking for 12V, 15V, 18V, 24V, 28V, 48V and -12V. The practical answer

Re: [time-nuts] Heliostat

Hi The most common use was to reverse the process …. you used it to obtain local solar time. Bob > On Jul 2, 2016, at 3:12 PM, Brooke Clarke wrote: > > Hi: > > I recently got an Eastern Science Supply Co. demonstration heliostat, that's > to say it's small enough to

Re: [time-nuts] python or matlab/octave for Keysight instruments?

Hi > On Jul 2, 2016, at 1:58 PM, Hal Murray wrote: > > > jim...@earthlink.net said: >> I'm fine with writing the SCPI commands and parsing the output, I'm just >> looking for the "glue" between "send_message_to_instrument" or >> "read_message_from_instrument" and the

Re: [time-nuts] Switching transistors, current sources, nonidealties and noise

istor as you can get it. You want the resistor right up against the base. Inductance in the base lead is a really bad thing in this case. Bob > On Jul 2, 2016, at 1:00 PM, Attila Kinali <att...@kinali.ch> wrote: > > On Fri, 1 Jul 2016 12:28:44 -0400 > Bob Camp <kb...@n1k.org&

Re: [time-nuts] Switching transistors, current sources, nonidealties and noise

Hi Works for both. Bob > On Jul 1, 2016, at 2:54 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> There is also the somewhat non-intuitive need to stick a low value resistor >> in the base. Done properly, they are very reproducible and reasonably >> insensitive to

Re: [time-nuts] Switching transistors, current sources, nonidealties and noise

Hi > On Jul 1, 2016, at 7:56 AM, Attila Kinali wrote: > > Moin, > > Thanks everyone for the answers! > > On Mon, 20 Jun 2016 01:45:24 -0400 > Charles Steinmetz wrote: > >> The transation frequency of the current source transistor is part of the >>

Re: [time-nuts] Cable length calibration

Hi > On Jul 1, 2016, at 3:40 AM, Mike Cook wrote: > > >> Le 29 juin 2016 à 22:18, Poul-Henning Kamp a écrit : >> >> >> In message <20160629192850.19c29406...@ip-64-139-1-69.sjc.megapath.net>, Hal >> Mu >> rray writes: >> At one point

Re: [time-nuts] The Nature of Noise

Hi If you are measuring noise, then C is the bad one in the group. If you are measuring something else, then it is possible that you are getting bad information. This is a classic argument about comparing devices from the same lot of parts. They might both have a very similar warmup curve or

Re: [time-nuts] GNSS antenna delays

Hi There are a lot of variables in all this. If you have a good antenna, it’s got a filter ahead of the preamp. It may also have a filter after the preamp. Just how wide these filters are … that depends. If you grab a bunch of SAW filter data sheets, you see numbers in the 10 to 25 ns range.

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

Hi > On Jun 29, 2016, at 5:08 AM, Pete Stephenson wrote: > > On Tue, Jun 28, 2016 at 12:14 AM, Van Horn, David > wrote: >> >> >> p...@heypete.com said: >>> I'm a little concerned about the speed at which the pulses need to be >>>

Re: [time-nuts] Datum Starloc II GPSDO issues

Hi I wonder if these were production line discards rather than pulled from equipment parts? That would explain the missing manufacturing date. They may still have production test code in them rather than final ship code. Bob > On Jun 27, 2016, at 9:32 PM, Mark Sims

Re: [time-nuts] OCXO noise as they retrace

Hi For most OCXO’s most certainly not. The typical OCXO improves on ADEV as it runs. That said, a good OCXO should have a 1 second ADEV of at least parts in 10^-12 rather than 10^-11. A 5370 should have a floor at 1 second of around 2x10^-11. You may be measuring your counter doing something

Re: [time-nuts] pick and place problems/design

Hi This whole thing *is* a multi solution problem. There is no one right answer for everybody and everything. It is refreshing to get past the whole “the world ends when we run out of DIP packages” hysteria that often grips us when talking about *building* a Time Nut gizmo. A *lot* of the

Re: [time-nuts] Impact of GPS antenna height measurments

Hi What are you using to determine the “correct” altitude of the antenna? In a lot of cases, the GPS is more correct (relative to it’s specified ellipsoid) than the reference being used. Bob > On Jun 26, 2016, at 9:02 AM, Mark Barettella via time-nuts > wrote: > > Using

Re: [time-nuts] Quartz Crystal Motional Movement

u...@t-online.de> wrote: > > Bob Camp: >> Every paper I have ever read on the intrinsic Q of quartz makes the claim >> that Q * F is a constant ( Q goes up as frequency goes down). Unless blank >> diameter gets in the way, this has been true for any >crystals I have ever

Re: [time-nuts] Quartz Crystal Motional Movement

Hi The key trick that is often missed while watching it done is the need to set it (tune it) to operate at the frequency you are looking for. In other words, if you are testing a 4 MHz crystal, you need to first tune the machine to 4 MHz. If you truly have a bag full of “mystery parts” that’s

Re: [time-nuts] Quartz Crystal Motional Movement

Hi Every paper I have ever read on the intrinsic Q of quartz makes the claim that Q * F is a constant ( Q goes up as frequency goes down). Unless blank diameter gets in the way, this has been true for any crystals I have ever used. Q does change as overtone changes, but that is not related

Re: [time-nuts] pick and place problems/design (was: OT stuffing boards)

Hi > On Jun 25, 2016, at 12:56 PM, Chris Albertson > wrote: > > At home I have a parts bin and I find I need to stock about two dozen > resister values. Ok, chip resistors run about ten for a penny. Buy 1,000 of each for a buck a value. So far you have spent $24

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