Re: [time-nuts] Affordable PoE 6-digit time displays?

Hi I think this is one of those really small market items. You can probably cobble one together from bits and pieces for less than you can buy a good one. Bob > On Jun 14, 2018, at 9:15 PM, David Andersen wrote: > > I'd hoped that ebay or aliexpress would yield a bounty given how seemingly >

Re: [time-nuts] Spectracom 8140T Line Tap Schematic

Hi > On Jun 14, 2018, at 9:31 AM, gandalfg8--- via time-nuts > wrote: > > > Hi Julien, > > > > Earlier replies that discussed removing the DC supply from the 8140 outputs > gave me the impression your requirement was to connect directly the outputs > of the 8140 without line tap

Re: [time-nuts] Raw phase data of super-5065

Hi I’d say both have a “something” with a period of roughly 18 to 20 hours in their data runs. Bob > On Jun 14, 2018, at 4:54 AM, Attila Kinali wrote: > > On Wed, 13 Jun 2018 08:19:58 -0700 > wrote: > >> Would be interesting to see a long plot of the two 5065 against each >> other! > > I

Re: [time-nuts] Spectracom 8140T Line Tap Schematic

Hi I think you would find a *lot* of smaller outfits “back in the day” running hand soldering lines. Small scale wave solder for through hole did not catch on the way reflow has for SMT. Dip solder was a rare item …. Bob > On Jun 13, 2018, at 11:28 PM, Charles Steinmetz wrote: > > Nigel

Re: [time-nuts] a newbie question: where can I purchase 794.7nm VCSEL for building CPT rubidium clock?

Hi For several decades the Efratom FRK was the only “compact” Rb on the market. By today’s standards it’s a bit large, but in that era it was quite small. They went through a couple of re-designs over the years, but kept the basic form factor and nomenclature. The M-100 is the military

Re: [time-nuts] Raw phase data of super-5065

other pair of >> 5065, one modified and the other not. >> This second test was carried out at another site 300Km from the first one. >> Both tests showed a better and more consistent medium/long term ADEV than >> the unmodified HP5065A. >> I want to clarify that these meas

Re: [time-nuts] Raw phase data of super-5065

er people could carry out the same tests in the medium and long term Adev > stability. > > Luciano > www.timeok.it > > > > > > Da "Bob kb8tq" kb...@n1k.org > A "Luciano Paramithiotti" tim...@timeok.it,"Discussion of precise time a

Re: [time-nuts] Raw phase data of super-5065

ese measures have the objective of verifying the > medium / long term stability and not the short term stability of the Super > version I agree it is improved.. > Luciano > > > Da "Bob kb8tq" kb...@n1k.org > A "Luciano Paramithiotti" tim...@timeok.it

Re: [time-nuts] Mark-- LH Milliseconds Display

Hi Even a “tenth of second” running display is not of much use to the human eye. Most OS’s will struggle with a “hundredth’s of second” display in terms of getting it through the display formatting code. Finding a monitor and display card that will do 1KHz refresh rates / frame rate will be

Re: [time-nuts] Raw phase data of super-5065

eople can compare your setting to there’s does need to be part of the process. Bob > > > > Da "Bob kb8tq" kb...@n1k.org > A "Luciano Paramithiotti" tim...@timeok.it,"Discussion of precise time and > frequency measurement" time-nuts@feb

Re: [time-nuts] nuts about position

Hi Hmmm …… that’s a very big difference between the RINEX and the “precision survey”. How do each compare to other receivers on the same antenna ( and super duper stable mount) ? Even with a tripod on the grass, meter level variations likely are not the tripod’s fault. :) Bob > On Jun 5,

Re: [time-nuts] Raw phase data of super-5065

Hi It is pretty well known that without “help” ( beyond the filter stuff on the super) the 5065 has fairly poor temperature stability and somewhat variable response to pressure and humidity. Taking two samples right off the production line likely would have given you different long term data

Re: [time-nuts] Source for DC-blocking 50-ohm terminators? (Spectracom 8140)

Hi Without the taps, the Spectracom system really does not do much for you at all. There is no isolation / no buffering / no nice multiple output frequency stuff. Much cheaper and easier to just use a simple 10 MHz amp if that is all you want to do. Since you have significant voltage on the

Re: [time-nuts] Source for DC-blocking 50-ohm terminators? (Spectracom 8140)

Hi DC blocked 50 ohm terminations are indeed a bit odd. One answer is to simply use the 75 ohm version and move on. The gotcha there is that they may / may not have a block that works well at 10 MHz ( = the cap is to small ). The one thing *not* to do is to run the device with no termination

Re: [time-nuts] nuts about position

Hi > On Jun 3, 2018, at 7:35 PM, Mark Sims wrote: > > As far as I'm concerned anything that you can do to improve the position > accuracy, environmental changes, noise environment, etc is a good thing. > Minimizing errors and disturbances can't hurt and may even improve things. > How

Re: [time-nuts] nuts about position

Hi Location will always impact things a bit. At some point it does become a minor contributor. What point that is varies with a lot of things. One of them is indeed the propagation path to the satellites. How much the ionosphere and troposphere mess things up is very much a “that depends”

Re: [time-nuts] nuts about position

Hi If you are doing a longer run into one of the data analysis services - it does not seem to matter much what the spacing on the readings is. One second data does not seem to produce any better result than 30 second data. I don’t think that the 3 second rate on the Trimble will have much

Re: [time-nuts] nuts about position

er aspects > weigh in, as being quick to have reduce biases in position and time. > You can resolve much by averaging etc. but that takes time. > > Cheers, > Magnus > > On 06/01/2018 02:10 PM, Bob kb8tq wrote: >> Hi >> >> I can’t say that’s a big surprise. The sili

Re: [time-nuts] nuts about position

Hi I can’t say that’s a big surprise. The silicon on these gizmos made it past the “overkill” point at least a decade ago. There’s only so much you can do with a noisy signal ….. Yes, there are indeed feature differences, ( like the Furuno pps ). The core of the device seems to have hit a

Re: [time-nuts] HP 5370B using manual start-stop

Hi We ran 5335’s in “long gate” mode via the gate open / gate close commands. It worked, but you had to compensate for rollovers. My guess is that you would run into similar stuff on the 5370A. Simple answer is to try it and see … That’s what we did on the 5335 and then worked through all the

Re: [time-nuts] nuts about position

Hi It’s not real clear what the magic L1 / L2 / L5 gizmo does for you right now today. As far as I can tell, the free processing services all only do two at a time. You can do L1 / L2 or L1 /L5. Possibly at some point in the future that will change. Even with “only two” a fancy device will

Re: [time-nuts] Tektronix FCA3103 ADEV measurement tau setting problem

Hi Any time I have tied a 53132 into TimeLab, I’ve used the serial port. That does a fine job of “talk only” data dump. Bob > On May 30, 2018, at 12:18 PM, Richard (Rick) Karlquist > wrote: > > > > On 5/28/2018 1:44 PM, Bob kb8tq wrote: >> Hi >> TimeLa

Re: [time-nuts] Tektronix FCA3103 ADEV measurement tau setting problem

Hi TimeLab will work with some counters and it will do most of the common plots. It is indeed free ….. Bob > On May 28, 2018, at 3:17 PM, Richard (Rick) Karlquist > wrote: > > I have a Tek FCA3103 300 MHz counter that measures ADEV > as a built in function. When I bring up the settings >

Re: [time-nuts] 58503A VS SR625

ng to Lady Heather I my worst S/N is > 35dB all time > > Pada Senin, 28 Mei 2018 21.17.25 GMT+7, Bob kb8tq <kb...@n1k.org> menulis: > > > Hi > > If you are seeing 0.3 ppb delta between various HP GPSDO’s the first question > would be “on for how long? / under wha

Re: [time-nuts] 58503A VS SR625

Hi If you are seeing 0.3 ppb delta between various HP GPSDO’s the first question would be “on for how long? / under what conditions?". The HP devices take a *long* time to settle in ( like weeks ) to their final best performance loop settings. To fully settle, they need to be locked the

Re: [time-nuts] GNS-500A Rubidium

HI Unless I’m missing something, that’s an *old* Efratom. I would not count on it working without some significant effort. The price is right though. Bob > On May 25, 2018, at 10:21 AM, Clint Jay wrote: > > Just spotted on eBay, a rather sorry looking GNS-500A Rubidium

Re: [time-nuts] 5950 Crystal impedance meter manual

Hi Basically when the modern era of network analyzer / standards calibrated devices came along, it was the end of most of these magic test sets with knobs and dials. The Saunders stuff lived on well into that era, mainly because it was relatively inexpensive and most of the calibration was

Re: [time-nuts] TrueTime XL-AK Issues

Hi My guess would be that they are not in a mode that allows them to lock. Some GPSDO’s require a “start” command. Others hold off locking until a site survey is complete ( or they have verified the last survey is correct ). Bob > On May 23, 2018, at 1:31 PM, Richard Solomon

Re: [time-nuts] 5950 Crystal impedance meter manual

Hi Gizmo’s like that were very common in the days before network analyzers became good enough to measure a crystal. They always were a troublesome item to keep running accurately. Without accuracy, their value was a bit limited. Every place I know of had a big drawer ( or cabinet ) of “magic

Re: [time-nuts] Sawtooth correction: next or previous PPS

Hi > On May 21, 2018, at 9:13 PM, Hal Murray wrote: > > > hol...@hotmail.com said: >> One thing to look out for when messing with sawtooth messages is the >> question of does the message come out before or after the PPS pulse... good >> look finding the answer in the

Re: [time-nuts] NEO-M8N vs. NEO-M8T

Hi Simple answer on any GPSDO is always “that depends”. The sawtooth correction improves the PPS into the device by at least an order of magnitude on most GPS modules. Less noise in pretty much always equates to less noise out. It also takes care of hanging bridges ( sawtooth stuck to one side)

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

Hi Backing up a bit …. If this is all about a system that can quantize to 52 ns at best … your ADEV plot shows everything *well* below that at all offsets you display. If you assume a +/- 1 LSB sort of quantization, you are out to 104 ns. That’s 10X anything on the plot. You would very much

Re: [time-nuts] Motorola GPS Antenna?

Hi Since timing is everything to TimeNuts ….. :) The Motorola TV plant ( known as the Franklin Park North plant, not to be confused with Franklin Park South where they made …. errr ….. oscillators ) to Panasonic in 1974. The whole transaction came as quite a shock to the people involved. The

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

Hi > On May 21, 2018, at 2:08 PM, Gary E. Miller <g...@rellim.com> wrote: > > Yo Bob! > > On Mon, 21 May 2018 14:00:41 -0400 > Bob kb8tq <kb...@n1k.org> wrote: > >>>> Ok, are you trying to hold close to UTC or simply have a second >>>>

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

Hi > On May 21, 2018, at 1:44 PM, Gary E. Miller <g...@rellim.com> wrote: > > Yo Bob! > > On Mon, 21 May 2018 13:41:08 -0400 > Bob kb8tq <kb...@n1k.org> wrote: > >> Ok, are you trying to hold close to UTC or simply have a second that >> is as

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

Hi Ok, are you trying to hold close to UTC or simply have a second that is as close to 1 second as possible? Bob > On May 21, 2018, at 1:33 PM, Gary E. Miller <g...@rellim.com> wrote: > > Yo Bob! > > On Mon, 21 May 2018 10:39:33 -0400 > Bob kb8tq <kb...@n1k.org

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

Hi Ok so they changed that from the earlier parts. Time marches on. Bob > On May 21, 2018, at 1:08 PM, Oleg Skydan <olegsky...@gmail.com> wrote: > > > From: "Bob kb8tq" <kb...@n1k.org> >> You have always been able to poll the time offset message

Re: [time-nuts] Improving ocxo temp control

mp needs to be very accurately > controlled. > Any similar experience ? > Could you suggest papers describing high performance analog or digital > controllers ? > Thx, > Gilles. > > >> Le 19 mai 2018 à 16:09, Bob kb8tq <kb...@n1k.org> a écrit : >

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

018, at 11:05 AM, Oleg Skydan <olegsky...@gmail.com> wrote: > > Hi! > > From: "Bob kb8tq" <kb...@n1k.org> >> Not by default You go through the 390 pages of their manual and eventually >> find the bits to turn this and that on. When you do, those magi

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

Hi > On May 20, 2018, at 11:49 PM, Mark Sims wrote: > > I think what Gary really wants is a GPS receiver with the most stable PPS > output available. Unfortunately that’s not how any of these devices are designed to be used. They all ( including the Furuno ) have a

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

Hi > On May 20, 2018, at 10:58 PM, Gary E. Miller <g...@rellim.com> wrote: > > Yo Bob! > > On Sun, 20 May 2018 22:53:37 -0400 > Bob kb8tq <kb...@n1k.org> wrote: > >> If you look at the section under “timing (page 79)” in the uBlox >> manual you

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

, you can get down to below 1x10^-9 at one second on your plot. The T version will automatically output the magic message with the data in it. Bob > On May 20, 2018, at 10:06 PM, Gary E. Miller <g...@rellim.com> wrote: > > Yo Bob! > > On Sun, 20 May 2018 19:26:33

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

Hi Just as a reference point, one can get 0.006/0.006/0.012 sort of errors with a fairly rotten antenna and 24 hours of data from a 2004 era L1 / L2 receiver. One key consideration is that the error bars on the “estimated locations” of the reference stations are close to those numbers. Bob

Re: [time-nuts] ✘NEO-M8N vs. NEO-M8T

Hi The “big deal” features on the T series are the ability to do single satellite timing and the auto output of the sawtooth correction information. Cranking sawtooth correction into your data will move the line down most of the way to the “JL” line. Bob > On May 20, 2018, at 7:03 PM, Gary

Re: [time-nuts] Cesium Clock Avialable

Hi At least these days, a 5071 comes back from the factory with the same Hazmat labels on it as it ships into their factory with. Bob > On May 19, 2018, at 4:43 PM, Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: > > > In message <b17ed93d-0178-456f-b448-a9369

Re: [time-nuts] Cesium Clock Avialable

all actually isn't. > There was a document from HP. But its been a long time. > I will bet folks ship the 5061s all the time without a thought either way. > Just saying. Neither right or wrong. > > Regards > Paul > > On Sat, May 19, 2018 at 2:18 PM, Bob kb8tq <kb...@n1k.org> wrote:

Re: [time-nuts] Cesium Clock Avialable

cheap as it came from a company that most likely gets > a discount we don't. > > Regards > Paul > WB8TSL > > > On Sat, May 19, 2018 at 1:02 PM, Bob kb8tq <kb...@n1k.org> wrote: > >> Hi >> >> >> >>> On May 19, 2018, at 11:

Re: [time-nuts] Cesium Clock Avialable

them putting it in. Bob > > Dana > > > On Sat, May 19, 2018 at 10:01 AM, Bob kb8tq <kb...@n1k.org> wrote: > >> Hi >> >> Unfortunately there really is no way to tell how much Cs is left in the >> tube. You can >> look at beam current and make a gues

Re: [time-nuts] Cesium Clock Avialable

Hi Unfortunately there really is no way to tell how much Cs is left in the tube. You can look at beam current and make a guess. All that really will tell you is that the fuel gauge is on empty or at least just off of empty. Bob > On May 19, 2018, at 2:30 AM, Paul Bicknell

Re: [time-nuts] Improving ocxo temp control

Hi One key point about the need for “zero gradient”: Crystals and many other components are quite sensitive to thermal gradients. Very small fractions of a degree (as a gradient ) can have significant impact on the frequency of an oscillator. One of many “interesting things” about

Re: [time-nuts] Improving ocxo temp control

Hi There are a number of papers out and about about the limits on OCXO performance. The bottom line is that coming up with a high resolution control circuit is the easy part of the task. Simple answer to the question: Set up a thermistor bridge and feed the difference into an op amp. Crank up

Re: [time-nuts] WTB: HP/Agilent/Symmetricom 58517A Distribution Amplifier

Hi What you really want is an LNA plus some filtering. MiniCircuits will sell you all sorts of “adequate” amplifiers. They show up surplus for reasonable prices. The key point is that ultra low noise figure it not needed. A 3db NF is just as good as 0.3 db in this case. The antenna sets the

Re: [time-nuts] WTB: HP/Agilent/Symmetricom 58517A Distribution Amplifier

rol variables somewhat. > > *Clay Autery > (318) 518-1389 > * > On 05/18/18 08:50, Bob kb8tq wrote: >> Hi >> >> From what I have seen, it is a rare setup that requires all amplified >> distribution. Yes, >> it is possible. Unless you are in that rare case, t

Re: [time-nuts] WTB: HP/Agilent/Symmetricom 58517A Distribution Amplifier

Hi >From what I have seen, it is a rare setup that requires all amplified >distribution. Yes, it is possible. Unless you are in that rare case, the MiniCircuits eight and sixteen port splitters do a great job for *way* less money. Bob > On May 17, 2018, at 10:33 PM, Clay Autery

Re: [time-nuts] TruePosition GPSDO Holdover Issues

Hi > On May 15, 2018, at 3:52 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> One thing to consider - if you get far enough north, the “hole” closes and >> you can get sat tracks from the other side of the north pole. Yes they are a >> *long* ways away. It’s no

Re: [time-nuts] TruePosition GPSDO Holdover Issues

lly well but for something like this might be akin to > watching grass grow:-) > > Nigel, GM8PZR > > > > > > > > > > -Original Message- > From: Bob kb8tq <kb...@n1k.org> > To: gandalfg8 <gandal...@aol.com>; Discussion of precis

Re: [time-nuts] TruePosition GPSDO Holdover Issues

with the hole to the north noticeably reduced and tending more to a > closed circle and signal levels generally higher all round too, partially at > least perhaps due to a change in antenna gain but either way another can of > worms opened and begging further investigation:-) >

Re: [time-nuts] China, GCJ-02 & cartography

Hi Running with a very normal WGS-84 GPS “by the sea shore” can easily show you underwater. That is very much a normal result of the model. It does not tell you what high (or low) tide level is going to be at your location. That stuff is simply to complex. The rest of it …… a lot of

Re: [time-nuts] Electronic Research Co. Precision Crystal Oscillator.

Hi Keep in mind that roughly 99.9% of all OCXO’s produced went into OEM specific applications with spec sheets that reflected the OEM’s requirements. Both the OEM and the manufacturer had reasons to keep those documents private. In both cases it made it more difficult for competitors to

Re: [time-nuts] Question about frequency counter testing

Hi > On May 14, 2018, at 1:50 PM, Oleg Skydan <olegsky...@gmail.com> wrote: > > Hi! > > From: "Bob kb8tq" <kb...@n1k.org> >>> If such conditions detected, I avoid problem by changing the counter clock. >>> But it does not so

Re: [time-nuts] Question about frequency counter testing

Hi > On May 14, 2018, at 5:25 AM, Oleg Skydan <olegsky...@gmail.com> wrote: > > Hi Bob! > > From: "Bob kb8tq" <kb...@n1k.org> >>> I think it will be more than enough for my needs, at least now. >>> >>>> From the 2.5 ns s

Re: [time-nuts] Question about frequency counter testing

Hi > On May 13, 2018, at 5:13 PM, Oleg Skydan wrote: > > Hi Magnus, > > From: "Magnus Danielson" >> I would be inclined to just continue the MDEV compliant processing >> instead. If you want the matching ADEV, rescale it using the >>

Re: [time-nuts] GPS Timing Antenna Failure - Long

Hi The shape of the radome on your typical timing antenna is all because of birds. If the antenna is 60 feet up a cell tower you do *not* want to have to pay a crew to go up there and knock the nest off of the antenna. Even in the flatlands, you can get multipath. All it has to do is bounce

Re: [time-nuts] Question about frequency counter testing

Hi > On May 13, 2018, at 1:31 PM, Oleg Skydan <olegsky...@gmail.com> wrote: > > Hi Bob! > > From: "Bob kb8tq" <kb...@n1k.org> >> I guess it is time to ask: >> >> Is this a commercial product you are designing? > > No. I hav

Re: [time-nuts] TruePosition GPSDO Holdover Issues

Hi When you are looking at timing, the SBAS / WAAS sat’s really don’t count as part of the total of 4 that you need for a basic fix. There also iis the subtle distinction of “tracking” vs “locked to” on some devices. Tracking means we might get adequate data soon and locked means it is good

Re: [time-nuts] TruePosition GPSDO Holdover Issues

Hi Assuming the device has the “normal stuff” in it, it will look at the location in memory and compare that to the current solution. If the solution is off by more than the limit, it will reject it. If it rejects enough data ( = no good solution) it goes into holdover. Some devices will

Re: [time-nuts] Question about frequency counter testing

Hi I guess it is time to ask: Is this a commercial product you are designing? If so, that raises a whole added layer to this discussion in terms of “does it do what it says it does?”. Bob > On May 13, 2018, at 3:07 AM, Oleg Skydan <olegsky...@gmail.com> wrote: > > Hi Bob!

Re: [time-nuts] GPS Timing Antenna Failure - Long

Hi As mentioned a number of times, quadrafilar antennas were only popular for a very short while back in the 1980’s. Once people started using GPS for “stuff” they rapidly lost out in the antenna race. They were made popular by an early NIST paper. Later on NIST effectively said “oops !!” in

Re: [time-nuts] Question about frequency counter testing

Hi > On May 12, 2018, at 1:20 PM, Oleg Skydan <olegsky...@gmail.com> wrote: > > Hi! > > From: "Bob kb8tq" <kb...@n1k.org> >> There is still the problem that the first post on the graph is different >> depending >> on the technique.

Re: [time-nuts] Commercially available empty ovens for oscillator testing?

Hi There are places that sell them. Most are looking for a couple thousand dollars for one. If that is inside your budget you might get in touch with them. Far cheaper to get an eBay scrap OCXO and use its parts. An OCXO depends on the combination of two things to make it stable: 1) The

Re: [time-nuts] Anybody have suggestions for time related science fair projects?

Hi > On May 12, 2018, at 7:01 AM, jimlux wrote: > > On 5/11/18 9:08 PM, Jeff Woolsey wrote: >> David.vanhorn wrote: >>> Measuring the speed of light (Fizeau or Michelson method? Other ways) >>> >>> >>> I saw a great demo of this at the Exploratorium in SF. They had a

Re: [time-nuts] Help Identifying this surplus Timing Module

Hi Ok, the gizmo on the front it an Altera CPLD. Not a lot of gates, so not a lot going on there. Whatever the real functions are, they are in the chip with no labeling. Even with the full information (let’s say): Takes in a 16 stream OC-blah blah and provides the following alarms on the

Re: [time-nuts] Help Identifying this surplus Timing Module

Hi The big chip with the sticker on it is an Altera FPGA. A picture of the back side might help a little (if there is anything on the back side …). Simple answer - it’s a nice source of parts …. Bob > On May 11, 2018, at 7:16 PM, CubeCentral wrote: > > Hello All! > >

Re: [time-nuts] Help Identifying this surplus Timing Module

Hi Given the frequency of the oscillator, it’s some sort of sync module for a telecom system. What data rate and what sort of coding …. who knows … Bob > On May 11, 2018, at 7:16 PM, CubeCentral wrote: > > Hello All! > > > > I would like to enlist your help in

Re: [time-nuts] HP 5372A

HI > On May 11, 2018, at 3:12 PM, Magnus Danielson > wrote: > > Hi Don, > > On 05/10/2018 02:59 PM, Don Murray via time-nuts wrote: >> Hi Magnus... >> >> >> Appreciate any help! >> >> I participate in the ARRL Frequency Measuring Test, >> and I would like to

Re: [time-nuts] HP 5372A

Hi Well, having actually run FMT virtually “in the back yard” of the transmitting station …. it’s surprising what 70 miles will do. In this case, back yard really does mean on the premises. There is a lot that gets into even fairly sort distance propagation. Bob > On May 11, 2018, at 1:52

Re: [time-nuts] Question about frequency counter testing

: > > Hi > > ---------- > From: "Bob kb8tq" <kb...@n1k.org> >> The most accurate answer is always “that depends”. The simple answer is no. > > I have spent the yesterday evening and quite a bit of the night :) reading > many interesting papers and several rela

Re: [time-nuts] Anybody have suggestions for time related science fair projects?

Hi NTP time offsets through various phases of the distribution process ….. Bob > On May 11, 2018, at 12:55 AM, Hal Murray wrote: > > > A few months ago, I was a judge for the county level middle school science > fair. (I'm not very good at what they wanted, but

Re: [time-nuts] Question about frequency counter testing

Hi > On May 10, 2018, at 1:44 PM, Oleg Skydan <olegsky...@gmail.com> wrote: > > Bob, thanks for clarification! > > From: "Bob kb8tq" <kb...@n1k.org> >> If you collect data over the entire second and average that down for a >> sin

Re: [time-nuts] Question about frequency counter testing

better sense > as it provides some measure > of defense against taking a sample that happens to be an outlier, yet > avoids the flaw of tending to average > the reported ADEV towards zero. > > Dana (K8YUM) > > > On Thu, May 10, 2018 at 9:21 AM, Bob kb8tq <kb...@n

Re: [time-nuts] Question about frequency counter testing

Hi If you collect data over the entire second and average that down for a single point, then no, your ADEV will not be correct. There are a number of papers on this. What ADEV wants to see is a single phase “sample” at one second spacing. This is also at the root of how you get 10 second ADEV.

Re: [time-nuts] how long dues this rubidium standard last for

Hi Rubidium standards are a “who knows” sort of thing in terms of life. Best guess for the telecom Rb’s is 10 to 20 years. For a normal Cs standard with a high performance tube, the life may be in the 6 or 7 year range ( I have replaced a couple of those). The HP 5065 is a rare beast. One sold

Re: [time-nuts] Ashtech Z12 question.

Hi What you describe sure sounds like a ram battery died sort of thing. I’ve never noticed one in the boards I’ve torn apart. I’d also admit that was a few years back …. Bob > On May 6, 2018, at 6:12 PM, Mark Sims wrote: > > I just added support for the Z12 to Lady

Re: [time-nuts] WWVB: measuring local 60 KHz noise

Hi First off, I don’t think there *is* an ideal antenna that “just works”. Maybe a proper set of EMAG probes that come with calibration sheets come close. For a home built this or that …. there are a lot of variables. First up is very much part of receiving WWVB in the first place. Coax to

Re: [time-nuts] WWVB: measuring local 60 KHz noise

Hi The sample rate on a sound card is not always a good indication of it’s performance. Some 192 KS/s cards have cutoff’s below 50 KHz. Others have a noise spectrum that rises quite a bit past 30 or 40 KHz. Lots to dig into …. Bob > On May 5, 2018, at 5:42 PM, Alberto di Bene

Re: [time-nuts] WWVB: measuring local 60 KHz noise

Hi If you want delay ( hardware delay and not propagation), calibrating a SDR should not be to nutty. Some boards ( the Lime SDR comes to mind) will generate a signal as well as receive one. That could be piped into a scope to make the measurement fairly easy. Once you know what is going into

Re: [time-nuts] WWVB: measuring local 60 KHz noise

Hi Even if you get the 60 KHz process working, a $20 GPS module ( or maybe $50) will do a much better job. That’s not saying *don’t* do the WWVB stuff. Just realize it’s limitations. A second limitation is that the new phase modulation process makes comparison a bit more complex. 60 KHz

Re: [time-nuts] LEA-6T TCXO measurements

in the time record. If you dig into the archives, there are lots of plots showing typical data. Bob > On May 4, 2018, at 5:18 AM, Gabs Ricalde <gsrica...@gmail.com> wrote: > > On Thu, Apr 26, 2018 at 8:36 PM, Bob kb8tq <kb...@n1k.org> wrote: >> Hi >> >> What y

Re: [time-nuts] What is considered the best deal now days on ...

Hi Outputs a pps is not impossible to find on an L1 / L2 receiver. Outputs 10 MHz is very unusual on an L1 / L2 device. Bob > On May 3, 2018, at 7:42 PM, Pete Lancashire wrote: > > ... a L1 / L2 receiver that also outputs either one PPS or 10 megahertz > > -pete >

Re: [time-nuts] nuts about position (cheap receiver)

Hi …… and the quoted errors are in the 10’s of cm range. Thus you need a few years, even if you are moving an inch per year. Bob > On May 3, 2018, at 2:19 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> If you have a very good survey grade receiver and take a

Re: [time-nuts] Racal 9475 Rubidium

Hi You *really* need to keep the baseplate of the FRK series devices down. Their reliability drops quite a bit as you go from 40 to 50 to 60 C on the baseplate. I would avoid boosting the input voltage without a very good heatsink ( or heatsink + fan ) setup. I’ve …. ummm ….. cooked … a

Re: [time-nuts] nuts about position (cheap receiver)

Hi If you have a very good survey grade receiver and take a long enough data set, yes you can watch your location drift in some parts of the world. In most locations, fixes a few years apart would be a better bet. Indeed this does get a bit far from the world of timing …… The distances

Re: [time-nuts] nuts about position (cheap receiver)

Hi The sites are aimed at improving position information. To the degree that having an accurate location for your antenna improves timing, simply doing that is a step forward for your GPSDO. Most sites also will give you information that shows the timing solution at a given point in time. To

Re: [time-nuts] nuts about position (cheap receiver)

Hi Thank goodness it now is almost all self contained. Typing three or for lines of a script is *so* last century :) Sounds very cool !! LH continues to do amazing things. She is an impressive lady. Do you ever have time to sleep? My guess is that some sort of write up for doing the

Re: [time-nuts] Racal 9475 Rubidium

Hi Ok, quick intro to Rb standards: On an Rb you have a light bulb. It’s a really weird bulb but a bulb none the less. On most (but not all ) designs the bulb has a finite life. Various improvements over the years have stretched out the life. Just when which outfits did which improvements ….

Re: [time-nuts] nuts about position

Hi The “drops stuff” problem is exactly what I saw trying to run at lower baud rates. The port is *not* full of data, there’s plenty of time to get it all out at a lower baud rate. For some reason (buffers maybe) these modules start dropping data *way* earlier than you would think they should.

Re: [time-nuts] nuts about position

Hi You mean that LH does not translate the data to the correct format *and* submit it for post processing ? There *is* a lot of data when you turn all this stuff on. If you can get above 115K baud, it’s well worth it. = One important qualifier to re-state. L1 post processing is

Re: [time-nuts] nuts about position

Hi If you are looking at doing a self survey on a timing module, there is a lot of information in the archives. It turns out that (like it or not) there is very likely to be a ~24 hour periodicity in your self survey data. Therefor something like a two, three, or four day survey will enhance

Re: [time-nuts] Question about frequency counter testing

> On Apr 27, 2018, at 2:47 PM, Oleg Skydan <olegsky...@gmail.com> wrote: > > Hi > > From: "Bob kb8tq" <kb...@n1k.org> > Sent: Friday, April 27, 2018 4:38 PM >> Consider a case where the clocks and signals are all clean and stable: >> >> B

Re: [time-nuts] Question about frequency counter testing

Hi So what’s going on here? With any of a number of modern (and not so modern) FPGA’s you can run a clock in the 400 MHz region. Clocking with a single edge gives you a 2.5 ns resolution. On some parts, you are not limited to a single edge. You can clock with both the rising and falling

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