Re: [time-nuts] HP5370A vs B version

Hi They both run hot and have “interesting” calibration procedures. Count on spending some time running through this and that to get the best performance out of them. The B does seem to run a bit better, but both meet the same basic specs. The SR610 is a very similar device (with some similar

Re: [time-nuts] Efratom MFS system Questions

Hi It’s been more than a while since I last tore into one of those beasts. My recollection is that the output modules have a set of buffer amps on them. Each buffer has filtering appropriate to the designated output frequency. One *could* convert a 5 MHz module to 10 MHz by swapping out a bunch

Re: [time-nuts] Clock accuracy

g this question : I wanted to know what sort of long term > accuracy I could expect from the GPS constellation - looks as if 1 part in > 10 to the 12th is about right. > Cheers!...Donald > C. > > On Sat

Re: [time-nuts] Noob question, NTP stratum 1.

Hi One of the gotcha’s with “cell phone” based timing is discovering that the provider has been a bit lax about making sure the time stamp on the signal is what it should be. The problem is less common with 800 MHz CDMA than other bands / services. One of the reasons we see a lot of this sort

Re: [time-nuts] Hobbyist and prototyping boards with U-blox ZED-F9P

Hi There was a lot of discussion on the Sparkfun F9P board about six months ago. Since then uBlox came out with their own board for the F9P. Like the Sparkfun board and the bare F9P modules it shows up at Digikey “most of the time”. For whatever reason, they go in and out of stock (which is

Re: [time-nuts] HP 10811 stabilizing time

Hi The “most often mentioned” run rate was “about 800 a month". It was never at all clear if that also came out to 10,000 a year or not. ( = how often did they hit that rate). If you wanted to buy one piece, I believe the price was $800. At that price, even 800 a month would be pretty good

Re: [time-nuts] Delayed WNRO ?

Hi Most modern devices have “delayed” rollover. There is some magic week number embedded in the code. Usually it’s the week that the firmware is finalized. Anything *before* that week number is assumed to be in the future. Bob > On Jul 24, 2019, at 1:01 PM, shouldbe q931 wrote: > > Hi All,

Re: [time-nuts] HP 10811 stabilizing time

Hi *Assuming* that we’re talking about 4 to 6x10^-10, you should be able to do better than that with the piston trimmer. I’m in no way suggesting that it is *easy* to do better than that. The bigger question is: how much value is there in doing better than that? What is the aging rate on

Re: [time-nuts] FSA3011 Frequency Stability Analyzer

Hi There was some chat a few weeks back about them and several questions came up about some of the features of the unit. I believe there was an inquiry into the people making the device to get some further information. If that *did* come back and get posted, I missed it. Bob > On Jul 26,

Re: [time-nuts] FSA3011 Frequency Stability Analyzer

Hi One of the questions earlier was about the “offset oscillator” in the device and if it was tuned in any way. If it is not tuned *and* it has modest stability, the exact frequencies you put in may impact the performance you get. Since there seems to be zip for command set, I’d bet there is no

Re: [time-nuts] Capturing NMEA and TICC timestamp data in time-correlated way?

Hi On many receivers the buffering process on the messages has an impact on arrival times. If you *only* use one message and never use any others that might not be a big deal. Most applications use a number of messages to be sure that the software knows what is really going on. You can

Re: [time-nuts] overtone crystal question

Hi You “shape” the blank to trap energy on some crystals. Also the energy distribution on the blank changes with overtone. You can change the electrodes to get more of “what you want” and less of “what does not matter”. Plating thickness also gets optimized based on overtone. There are a long

Re: [time-nuts] overtone crystal question

Hi Bottom line - if you are designing a filter, you need the real values for the Cm, Lm and C0. Guessing at them is likely to lead to trouble if it is a reasonably complex filter. Rm generally goes as the overtone. It can deviate quite a bit from that (as can the other parameters) depending

Re: [time-nuts] FA2 counter Picture

ry > >> On Sep 30, 2019, at 9:39 AM, Bob kb8tq wrote: >> >> Hi >> >> If you look at the date code on the OCXO, it is going on 5 years old. That’s >> a part that >> was bought surplus somewhere. >> >> Bob >> >>> On Sep 30, 2

Re: [time-nuts] Talking Clock

Hi Based on only dimly remembered conversations long long ago: Getting all the “message fragments” so they sound natural and not choppy is not quite as easy as it seems at first. It’s by not quite rocket science, but there is more fiddling involved than one might think. One “solution” is

Re: [time-nuts] Two types of GPDSO / Rubidium

; > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > >On Thursday, September 26, 2019, 11:56:56 AM EDT, Bob kb8tq > wrote: > > Hi > > There are some “simple” answers to this: > > 1) You can (and many of us do) set up to

Re: [time-nuts] Am I doing something wrong?

Hi If the OCXO only makes it 6x10^-10 past 10 MHz, that’s not enough for the unit to lock properly. 40 Hz tune range looks fine so not a shorted tune line. New best guess would still be an OCXO problem. Swap it out and see what happens. The OCXO’s show up on eBay all the time. Who knows what

Re: [time-nuts] Am I doing something wrong?

Hi If your OCXO tunes to 10 MHz at -3.5V and it used to tune at +0.5V, it sounds like the tune line is shorted somewhere. That could be inside the OCXO or outside. If the short is “noisy” (and that is not unusual) you aren’t going to get it to lock. You need to figure out where the short is.

Re: [time-nuts] WWV 100th anniversary event

Hi So …. who else is going? Bob > On Sep 19, 2019, at 6:44 PM, Tom Van Baak wrote: > > The following info via NIST: > > > > NIST is celebrating the 100th anniversary of WWV. The event is limited to 100 > guests, but there is still plenty of space available. > > If you are interested,

Re: [time-nuts] Thunderbolt frequency error when locked

Hi Well, you need to leave a lot out to keep it brief. The answer is “somewhere in the 1x10^-10 to 1x10^-11 range. As long as you are not stating a tau or a confidence factor, any number in that range could be right. = Based on having done this a lot of times there are a couple of ways

Re: [time-nuts] FA2 internal reference oscillator test

Hi If these are like the previous gear from the same designer, the parts (like the OCXO) that go in will vary quite a bit. In the past they seemed to be built by a wide range of people getting parts from a wide range of sources. If there is any ID on the OCXO, it’s probably worth passing

Re: [time-nuts] FA2 counter Picture

Hi If you look at the date code on the OCXO, it is going on 5 years old. That’s a part that was bought surplus somewhere. Bob > On Sep 30, 2019, at 2:15 AM, ew via time-nuts > wrote: > > > > From Juerg my partner in crime > > Atmel MEGA328 > Altera MAX II EPM570T100 > AD8307 > FTDI

Re: [time-nuts] Looking for documentation for GPSTM BY SYMMETRICOM (not Trimble)

Hi Both GPSDO’s were *sold* to Nortel. Neither one was made by them. The two vendors that you most commonly see popping up on eBay are Symmetricom ( now Microchip) and Trimble. There may have been other vendors as well. If you are looking for schematics and block diagrams on any surplus

Re: [time-nuts] Am I doing something wrong?

Hi The steering on the TBolt comes from code phase measurements on the incoming GPS signals. The pps is derived directly from the 10 MHz by division. Since the OCXO is phase locked to the GPS, the PPS follows along. Indeed they have the usual “reset the counter” stuff when things are big time

Re: [time-nuts] Two types of GPDSO / Rubidium

Hi The first gotcah is that the distinction is not very clear. A TBolt varies the frequency of the OCXO in the GPSDO. GPSDO’s that use Rb’s can and often do vary the frequency. Indeed some devices use a DDS to generate an output rather than varying something else. I suspect that is what you

Re: [time-nuts] Are there any company selling refurbished/reconditioned Cesium tubes?

Hi Based on several replacements on a “high performance” 5071 …. 6 to 7 years of 24/7/365 seems to be about the point things start to get flakey. Maybe not dead, but crazy enough that it lets you know it needs a new tube ( = ADEV is not even close to what it should be ..). Cost several years

Re: [time-nuts] generalization of three cornered hat

Hi …….. and if you want to dig into ensembles of “non similar” clocks, you want to look into David Allan’s Smart Clock stuff…. http://www.allanstime.com/Publications/DWA/ There’s also a lot of stuff there on clock ensembles in general. Bob > On

Re: [time-nuts] E1938A source code/ firmware

Hi The gotcha with averaging multiple GPS modules is that there are a lot of common mode issues present. The averaging will help with the random noise stuff, but will not do much for the atmosphere, ephemeris, and other “external” limits. Unfortunately those limits are pretty significant

Re: [time-nuts] Advantages of GNSS ???

Hi On the F9P you have the specific issue of L1 / L2 with older GPS satellites. The device only does L2C. That cuts the “population” roughly in half. This is not a great thing for a “GPS only” setup with that device. BIPM does not directly control or feed timing into the various GNSS

Re: [time-nuts] Switching 1 pps signal

Hi Indeed the fast rise time of just about any modern digital signal gets energy up into the GHz region. Isolation wise, the simple answer is often to just disable the signal when not in use. In a one at a time system, that takes care of cross talk / feed through. There are a lot of “always

Re: [time-nuts] Advantages of GNSS ???

HI Actually a monotonous ( = un-exciting) GPSDO is a *really* good thing :) Having one that does exciting stuff from time to time is *not* at all what you are after :) Now we get to find out what auto spell check did to all of that …... Bob > On Jul 9, 2019, at 3:57 PM, David G. McGaw >

Re: [time-nuts] Advantages of GNSS ???

Hi Well, if you ever get back into it: You play games with varicap diodes to straighten out the curve. You may bias them, you might put them in parallel, you might put a coil or a cap across them. You can get the curve plenty flat enough for a control loop. Hopping / discrete steps

Re: [time-nuts] Advantages of GNSS ???

Hi TCXO’s are very different beasts than OCXO’s. In an OCXO, the crystal is not exposed to any significant temperature change. Bob > On Jul 9, 2019, at 8:05 PM, Mark Goldberg wrote: > > That is the dirty little secret of crystals. Manufacturers will test the > temperature response in one

Re: [time-nuts] Raspberry Pi TCXO Hat

Hi Congratulations !!! You have just invented Sync-E. Seems like *maybe* somebody beat you to it …. https://en.wikipedia.org/wiki/Synchronous_Ethernet Turns out it is one way to get *frequency* to a device (like a cell site). Just how well

Re: [time-nuts] can of worms: time-of-day in a community radio station

Hi Since “rogue” servers are rare, bumping up the number of servers fairly quickly gets you to a very high degree of confidence. Is that 5, 7, 9, or 11? It sounds like a wonderful topic for somebody’s thesis or dissertation :) Given that this is a free resource and that the network usage is

Re: [time-nuts] A simple sampling DMTD

Hi > On Nov 2, 2019, at 8:41 PM, Jan-Derk Bakker wrote: > > Dear all, > > Attila got me thinking with his remark: > > I am a bit astonished by the high noise level you have. I would have >> expected >> this to yield something below 1ps, judging from what we got from what >> Nicolas >>

Re: [time-nuts] Question for my new GPSDO

Hi Stepping back a bit here ….. All oscillators have phase noise. It’s going to vary with the offset from carrier. What you get at 10KHz will be much better than what you get at 1Hz. As long as the EFC does not make this any worse, there is no need to get very crazy. Putting the added noise 40

Re: [time-nuts] A simple sampling DMTD

ith the local VCXO > PLL'ed to the input from their maser; I'm looking at a similar setup (with > the expected LO performance being significantly worse than the incoming > signals). > > JDB. > > On Sun, Nov 3, 2019 at 2:40 PM Bob kb8tq wrote: > >> Hi >>

Re: [time-nuts] Cold Rubidium over hyped?

Hi > On Nov 8, 2019, at 11:18 PM, cdel...@juno.com wrote: > > The pressure sensitivity for a classic design can easily be eliminated. > > I'm pretty sure that the old Varian R20 cell was mostly immune. > > Either using the R20 design or stiffer convex ends in a modern design > would work. > >

Re: [time-nuts] FA-2 questions

tors were a bit loose and rattling but that was an easy fix. > Otherwise it looks good. > > -Bob N3XKB > > On Sat, Oct 26, 2019 at 5:14 PM Bob kb8tq wrote: > >> >> So another question: what firmware / rev’s do people have now? >> >> Bob >> &g

Re: [time-nuts] Mounting thread on TopGNSS GN-GGB0710

tapering. Bob > On Oct 29, 2019, at 11:01 PM, Denny Page via time-nuts > wrote: > > I have two of these. They are both 5/8-11, however they were both tapered. > The taper can be removed with a hand tap. > > Denny > > >> On Oct 29, 2019, at 15

Re: [time-nuts] time-nuts Digest, Vol 184, Issue 13

Hi For less than the price of a brand new tube, you can take it over and get it run through a 3D X-Ray setup. Not cheap, but then you will *know* what’s what in this specific tube. Last time I got into doing that sort of thing it was way more expensive than what I would spend in this case.

[time-nuts] uBlox NEO/LEA M9N

Hi uBlox has out a new series of L1 modules. They appear to run 4 GNSS systems at once. The only thing that is even close to documented is the M9N. One would *guess* that there will be an M9T eventually. Still not much sign of ZED-F9T’s out in the wild other than direct from the uBlox store.

Re: [time-nuts] Confusion over Thunderbolt - noob is going crazy

Hi “Thunderbolt” is the name Trimble uses for their line of GPSDO’s. They have used it for almost 30 years. They have had at least a dozen different models within their line of GPSDO’s. Back about ten to fifteen years ago, a 911 location system started to be scrapped out. It was being

Re: [time-nuts] Confusion over Thunderbolt - noob is going crazy

Hi None of the GPSDO’s commonly available on eBay have firmware updates available for them. They also pretty much all do not have schematics or service manuals. It is rare to find a model that has an operating manual. Bob > On Nov 15, 2019, at 3:20 PM, Taka Kamiya via time-nuts > wrote: >

Re: [time-nuts] Need help in test board pinout for SA22.c oscillator - thanks in advance

Hi You probably need more heat sinking than that assembly provides. It’s a case of “better to much than to little”. The life of the device will extended with more heat sinking. Bob > On Nov 7, 2019, at 2:47 PM, Fio Cattaneo (.US) wrote: > > Hello folks, I just got a Symmetricom SA22.C

Re: [time-nuts] tracking position & orientation

Hi Indeed, I do a better job of detecting the impact of humidity ( = rainy season ) on my deck then I do detecting anything else on a fairly short baseline. I *do* get correct distances and angles between the antennas (as verified with a tape measure). One thing you can do (with some effort)

Re: [time-nuts] tracking position & orientation

Hi At least right now, it is the “king of the hill” in terms of low cost modules that will do L1 / L2. If the target application is precision survey work, you do want (at least) dual band reception. All of the post processing outfits are looking for that sort of data. I do not know of any

Re: [time-nuts] Difference in antennas

Hi Way back in time, the first gear out there to use what we now look at as “normal” antennas was survey gear. For various reasons they decided on a 12V power supply and 40 to 50 db of gain in the preamp mounted in the antenna. They also got into L1 / L2 pretty quickly. A bit later the cell

Re: [time-nuts] Difference in antennas

e: >>> >>> So concensus is, 50dB gain antenna is too much gain, unless feed line >>> is too long, reception is poor, or there are other circumstances extra gain >>> is desired? >>> >>> --- >>> (Mr.) Taka Kamiya >

Re: [time-nuts] tracking position & orientation

Hi If NIST puts their real time data on any of the networks, you may be able to shortcut the process. Goddard puts up data so indeed NIST may also do so. The trick is to stream the data real time into the F9P or into a PC. You effectively solve for the distance and bearing to the “reference”

Re: [time-nuts] Are minutes more important in astronomy than seconds and hours ?

Hi That’s a very unique piece of history. Hopefully you were able to get it. Bob > On Nov 23, 2019, at 3:29 AM, Jean-Louis Rault wrote: > > Hi all > > A friend of mine offered me a secondary electric clock that was in use at > Observatoire Royal de Belgique, in Brussels, at the end of the

Re: [time-nuts] Difference in antennas

modern GPS that expects modest antenna gain when it's > plugged into a system with a 50dB gain antenna at the top. > > Thanks! > John > > > On 11/21/19 8:00 AM, Bob kb8tq wrote: >> Hi >> >> Way back in time, the first gear out there to use what we now look

Re: [time-nuts] tracking position & orientation

plus rotation > around the axes. > > What hardware/software would be suitable for a TimeNuts (PositionNuts?) > project like this? > > — Eric K3NA > > >> On 11/21/19 8:00 AM, Bob kb8tq wrote: >> Hi >> >> Way back in time, the first gear out there to

Re: [time-nuts] Difference in antennas

ception is poor, or there are other circumstances extra gain is > desired? > > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > >On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq > wrote: > > Hi > >

Re: [time-nuts] Synchronization

should equate to at least microsecond synchronization I think > > > > > On Tue, Dec 3, 2019 at 10:01 PM Bob kb8tq wrote: > >> Hi >> >> It looks like “your thread” just ran into “my thread” :) >> >> I’m doing some digging on a l

Re: [time-nuts] Trimble Tbolt temperature

Hi The temperature chip is there to “learn” the TC of the unit while it is in lock. If and when the unit goes into holdover that information is used to compensate the unit. If the environment does not change much when you are in holdover this may be a benefit. If the HVAC goes when the holdover

Re: [time-nuts] WiFi timings

Hi That’s good data, if a bit depressing :( …. I had hoped for a bit better performance. I may need to rethink some of this. I’m slowly building up a pile of parts and will take a shot at something to see what’s what. Thanks! Bob > On Dec 3, 2019, at 8:52 PM, Hal Murray wrote: > > I have

Re: [time-nuts] 1 pps Accuracy in two locations

Hi Taking “a few ps” to mean 1 ps (which is *not* what was said), you likely need to have a pulse to pulse performance that was good to << 1x10^-12 at 1 second. First step is to get a couple of standards that have an ADEV below 1x10^-13 at 1 second. How much below that level is going to depend

Re: [time-nuts] Synchronization

Hi Welcome ! The answer to any good question will always be “that depends” :) First depends is what sort of module: Just about any GPS that is doing a reasonable job will sync to under 50 ns. That’s without correcting for sawtooth error. The sync would be device to device over a local

Re: [time-nuts] Synchronization

Hi Ok, for survey work there *is* an alternative. It takes care of the location of the “rover” as well as the time. uBlox has a ZED-F9P module for around $100 that will do the trick. It is L1/L2, but the cost penalty isn’t all that great in this case. I don’t know if that would be a practical

Re: [time-nuts] Lowest Power NTP Server

Hi > On Dec 3, 2019, at 7:55 AM, Hal Murray wrote: > > > If a Raspberry Pi fits your energy budget, that's probably the simplest way > to > go. There are lots of them running with GPS hats. > >> More or less, 0.5W on a 5AH 12V battery runs for 120 hours. Something at 5W >> only runs for 12

Re: [time-nuts] Synchronization

Hi It looks like “your thread” just ran into “my thread” :) I’m doing some digging on a low power WiFi based NTP setup. RPi’s will be part of (but not all of) the mix there. So far the conclusion is that milisecond timing is what you are going to get from a NTP on a WiFi based RPi. If

Re: [time-nuts] Lowest Power NTP Server

Hi There are a bunch of devices out each doing their own thing. Some are running 100% of the time, others get power cycled “as needed”. There also are a range of OS’s involved. Having everybody wake up at once …. not practical. However if the “broadcast” NTP approach was the method of choice,

Re: [time-nuts] Trimble Tbolt temperature

Hi Again, since it’s a Kalman, even the people who designed it were a bit unclear about just what was going on inside. Was 0.1C data useful vs 1C ?…. nobody really knew. Based on many measurements of the TC of the DAC / Ref on the TBolt, it could indeed use some “help” when in holdover. One

Re: [time-nuts] Phase Detectors/Mixers for DMTD and PN measurements

HI For quite a while, the “quick and easy” way to do it has been to run one of the Mini Circuits RPD parts into a > 5K load at audio. You get a nice big output voltage without a lot of crazy effort. Follow it with the highest voltage / lowest noise op amp you can find …. Bob > On Dec 11,

Re: [time-nuts] Trimble 57963

Hi 5V and even 3.3V OCXO’s are fairly common these days. They show up in the catalog pages of a number of outfits and have for a decade or two. Trimble buys OCXO’s on the open market. They have used several suppliers over the years. The spec’s are indeed unique to Trimble, but by no means

Re: [time-nuts] Quartz oscillator slow drift/aging

Hi That’s unexpected on an OCXO that may have been power off for a decade or more. Let it run for a month and see how it’s doing then. Bob > On Dec 2, 2019, at 2:30 PM, AC0XU (Jim) wrote: > > Time Gurus- > > I have a FPS 1150A quartz oscillator with the 1 PPS disciplining option. With >

Re: [time-nuts] Trimble Tbolt temperature

Hi Since the DAC / reference is the main source of error, placing the sensor a bit away from the OCXO makes sense. You also don’t want to watch the OCXO heat the board. You want data on the outside temperature. Since it’s all buried away in a Khalman filter, even the people who designed it

Re: [time-nuts] Synchronization

Hi One timing issue could be that USB is not that great for timing. Since it is packet based it introduces jitter in the link. Running NTP on a “traditional” RPi is unlikely to produce numbers below a milisecond. Indeed I’m digging into that for what I’m working on ….. Bob > On Dec 5, 2019,

Re: [time-nuts] Quartz oscillator slow drift/aging

Hi Yikes That should read “expected on an OCXO” !!! Sorry !!! Bob > On Dec 5, 2019, at 8:05 AM, Bob kb8tq wrote: > > Hi > > That’s unexpected on an OCXO that may have been power off for a > decade or more. Let it run for a month and see how it’s doing then. >

Re: [time-nuts] Synchronization

busy while I’m also trying to sent time. Bob > On Dec 5, 2019, at 2:21 PM, jimlux wrote: > > On 12/5/19 5:16 AM, Bob kb8tq wrote: >> Hi >> One timing issue could be that USB is not that great for timing. Since it is >> packet based it introduces jitter in the link. Ru

Re: [time-nuts] Synchronization

ming on the USB at all > > > On Thu, Dec 5, 2019 at 6:00 PM Bob kb8tq wrote: > >> Hi >> >> One timing issue could be that USB is not that great for timing. Since it >> is >> packet based it introduces jitter in the link. Running NTP on a >> “tradit

Re: [time-nuts] 88Sr+ ion-clock live stream

Cool !!! > On Dec 6, 2019, at 10:39 AM, Anders Wallin > wrote: > > Hi all, you may find our live-stream from the lab amusing: > https://www.youtube.com/watch?v=z9VFbs4FogY > > The central bright dot is fluorescence at 422nm from laser cooling a single > trapped 88Sr+ ion. The ion emits about

Re: [time-nuts] can of worms: time-of-day in a community radio station

Hi Once you dig into all the sources of delay, the asymmetry is much more likely to be dimensioned in miliseconds than in microseconds. There are a lot of things that contribute to the total. Bob > On Oct 20, 2019, at 7:31 PM, Hal Murray wrote: > > > f...@cattaneo.us said: >> Maybe I

Re: [time-nuts] GPS Antennas

Hi There are a lot of 3D printers out there that happily print ABS …. Bob > On Oct 15, 2019, at 10:17 AM, Attila Kinali wrote: > > On Fri, 6 Sep 2019 10:07:29 -0700 > Nick Sayer via time-nuts wrote: > >> I’m late to the party, but my go-to antenna is the Gilsson marine antenna. >> If >>

Re: [time-nuts] FA2 internal OCXO orientation sensitivity

Hi A lot depends on the source of the tip sensitivity. If it is acceleration then indeed vibration will get to you. It’s also possible that the sensitivity is due to thermal issues. In that case, vibration will not be as big an issue. Worst axis is about +/- 3 ppb so it could be from either

Re: [time-nuts] GPSDO+PC as a NTP server

Hi The “ideal” solution (at least to me) would be a setup that let you estimate the time based on each system independently. Even things like survey locations vary a bit system to system. Give each one the “fix” that it thinks is best and go from there. Then report the output PPS time offset

Re: [time-nuts] HP5071A with bad tube.... can I get one used?

> (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > > On Thursday, October 24, 2019, 2:23:39 PM EDT, Bob kb8tq > wrote: > > > Hi > > Based on running a high performance tube version of the 5071A for a number of > years, t

Re: [time-nuts] HP5071A with bad tube.... can I get one used?

Hi Based on running a high performance tube version of the 5071A for a number of years, the tubes last about 5 to 7 years when run 24/7/365. Once they die, the practical ($$$) alternative is to send the beast back to the factory for a new tube. Indeed given the price and the complexity of

Re: [time-nuts] HP5071A with bad tube.... can I get one used?

ogether. > Cheers; > > Tom Knox > > 303-554-0307 > > act...@hotmail.com > > "Peace is not the absence of violence, but the presence of Justice" Both MLK > and Albert Einstein > > ____ > From: time-nuts on behalf of

Re: [time-nuts] Mounting thread on TopGNSS GN-GGB0710

Hi The ones I’ve seen all thread fine onto the standard survey poles. I believe that is a 5/8-11 thread. Bob > On Oct 29, 2019, at 7:54 AM, David C. Partridge > wrote: > > Hi all, > > I just received one of these and of course it doesn't fit the Shakespeare > 4705 Adapter (1" mast to 1"

Re: [time-nuts] Question for my new GPSDO

Hi You (sort of) have run into two problems: 1) The GPSDO takes forever and ever to lock ( = the gain is to low / the time constant it to long) 2) The GPSDO has to much jitter ( = the gain is to high / the time constant is to short) Obviously, you can’t solve both of these problems by

Re: [time-nuts] HP 5065A owners, a question!

Hi If I’m doing stuff, they both are powered up. I run a GPSDO as the local standard so that is what runs 24/7/365. In a normal year, they are powered up about 50% of the year. Bob > On Oct 23, 2019, at 11:34 AM, wrote: > > Hi, > > How many of you leave your 5065A on all the time? > >

Re: [time-nuts] can of worms: time-of-day in a community radio station

Hi A very normal internet based NTP setup will do what you wish to do. The main task is to make sure that your devices are *really* running NTP and not some odd thing built into their OS. The more devices / operating systems / OS versions / system configurations you have the more exciting

Re: [time-nuts] can of worms: time-of-day in a community radio station

y experience. > Regards > Paul > > > On Fri, Oct 18, 2019 at 6:02 PM Bob kb8tq wrote: > >> Hi >> >> A very normal internet based NTP setup will do what you wish to do. The >> main task is to make >> sure that your devices are *really* running NTP and not

Re: [time-nuts] Using commercial video amplifier for 10MHz clock distribution.

Hi What is the objective? If this is a setup to feed a bunch of RF test gear on a lab bench, that’s a petty typical thing for roughly 99% of the “need” out there. The gear sits there forever and ever connected to the end of the same piece of cable. It has a PLL of some sort inside the box

Re: [time-nuts] GPS Antennas

Hi The standard process after printing ABS is to vapor the part. That forms a solid surface. Bob > On Oct 15, 2019, at 12:16 PM, Attila Kinali wrote: > > On Tue, 15 Oct 2019 11:29:08 -0500 > Bob kb8tq wrote: > >> There are a lot of 3D printers out there that happily p

Re: [time-nuts] HP5071A with bad tube.... can I get one used?

by the regulation. Visit the Symmetricom >> web sites for more information. >> 3. Attach a Dangerous Goods Declaration (authorized, red-stripe bordered >> document) and fill identification as follows: Proper name CAESIUM; >> Class 4.3; UN No. UN1407; Packing group I; Quantity

Re: [time-nuts] GPSDO+PC as a NTP server

Hi There are a number of GPS errors that turn into “long period” disturbances. A normal OCXO (even a good one) runs with a fast enough loop that they do appear in the output of the GPSDO. One (of many) sources of this sort of error is the 12/24 hour cyclical nature of GPS orbits. Another is

Re: [time-nuts] Cold Rubidium?

Hi If you look at the ADEV plot, there is some sort of bump out in the 1 to 2 days region. That would suggest it’s not 100% immune to the local environment…. The box is big enough that you *might* fit a chiller in it. If so, heat would need to be vented. I see no (obvious) vents or heatsinks.

Re: [time-nuts] FA-2 questions

Hi Taking the “questions” topic in a bit different direction ….. If the FA-2 is like the other projects from the same people, there is active work being done on the project. That is likely to create updated code for the device as issues are spotted. Is anybody on the list linked into that side

Re: [time-nuts] "Ancient 5065..."

ent. Annoying was his comment. > Regards > Paul > > On Mon, Oct 21, 2019 at 11:07 PM Bob kb8tq wrote: > >> Hi >> >> I think that you never really know what’s what until *you* can poke at it >> and try to fire it up. >> If the device (any device) was run

Re: [time-nuts] "Ancient 5065..."

Hi I think that you never really know what’s what until *you* can poke at it and try to fire it up. If the device (any device) was run for decades, parts probably were swapped to keep it running. Bob > On Oct 21, 2019, at 4:16 PM, Ulf Kylenfall via time-nuts > wrote: > > Hmm... > > On

Re: [time-nuts] Digital Phase Lock Loops

Hi Unless the 100 MHz “VCO” is an OCXO, it is going to be tough to keep things locked at a fractional Hz sort of bandwidth. It’s simply a matter of how much the phase / frequency is likely to change while you are trying to get it to lock / keep it locked. Things like shock and vibration get into

Re: [time-nuts] Chinese NTP Time server

Hi One might *guess* that the blurred area has even more workmanship issues than some other places on the board ….. :) If you look at it as a GPSDO + NTP (if that’s what it is, the listing talks a lot about “optional” this and that) then the price isn’t totally insane. My biggest question

Re: [time-nuts] Estimating expected time error using info from manufacturers' data sheets

Hi One issue you will quickly run into is the nature of the data sheet parameters. If you are buying a device you can afford, they rarely have a lot of detail. This is hardly unique to frequency references. The real device may exceed the spec’s by a very wide margin. It also may just barely (if

Re: [time-nuts] 100 MHz decade divider advice needed

Hi 74AS161 / 163 are rated to 125 MHz. Bob > On Nov 29, 2019, at 6:50 PM, Perry Sandeen via time-nuts > wrote: > > Yo Bubba Dudes!, > I'm considering attempting making a 10 MHz frequency difference meter sort > of based on the Ticor 527. > The design calls for using 100 MHz OCXO's and

Re: [time-nuts] John Fluke test equipment tutorial

Hi Both the Frequency Control Symposium and the PTTI proceedings are archived by their respective parent organizations. DVD’s are available with the old versions on them. The papers done by NIST are on the NIST website. Much of the rest is protected / restricted. Bob > On Nov 27, 2019, at

Re: [time-nuts] Lowest Power NTP Server

Hi So something like one of the many ESP32 based boards? Of course when it comes to the “code from scratch” part there is the problem that I’m pretty (most would say very …) lazy :) :) :) Bob > On Dec 1, 2019, at 12:29 PM, Poul-Henning Kamp wrote: > > > > You can do better than

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