Re: [time-nuts] AN/URQ13 reference AT cut crystal? ==> Crystal Robot

is “to fast” to get good ADEV …. how would you know that … hmmm .… run another autoclave (all that after you had tooled a giant cold weld package /process machine /welder to do your testing in … yikes ….) Fun !! Bob > On Feb 18, 2021, at 10:40 AM, Poul-Henning Kamp wrote: > > -----

Re: [time-nuts] AN/URQ13 reference AT cut crystal? ==> Crystal Robot

> On Feb 18, 2021, at 9:57 AM, Poul-Henning Kamp wrote: > > -------- > Bob kb8tq writes: > >>> What properties would you program a quartz-crystal-prototyping robot >>> to search for ? >> >> You very much want to (eventually) know about perturbatio

Re: [time-nuts] AN/URQ13 reference AT cut crystal?

gt; shaped curve made no sense. Also I do not recall seeing a crystal curve that > looked like an upside down U. You would need to get down to around -20 C to see the other side of the AT curve. Bob > Regards > Paul > WB8TSL > > On Thu, Feb 18, 2021 at 7:13 AM Poul-Hen

Re: [time-nuts] AN/URQ13 reference AT cut crystal? ==> Crystal Robot

Hi > On Feb 18, 2021, at 6:53 AM, Poul-Henning Kamp wrote: > > -------- > Bob kb8tq writes: > >> Turning an “idea” into a production capable part involves making many >> batches of test samples. Think in the thousands of batches and hundreds >> of parts

Re: [time-nuts] AN/URQ13 reference AT cut crystal?

Hi This is probably a better way to look at the various aspects of a quartz crystal: http://www.mt-berlin.com/frames_ao/descriptions/sio2.htm First thing to look at is the number of directions you get a different speed of sound. Each

Re: [time-nuts] AN/URQ13 reference AT cut crystal?

Hi > On Feb 17, 2021, at 6:31 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> …… and there are whole families of crystal cuts that have been optimized for >> use as thermometers. There is no need to compromise on something like an AT >> or SC if you are after temperature. There are lots of

Re: [time-nuts] AN/URQ13 reference AT cut crystal?

Hi > On Feb 17, 2021, at 2:10 PM, Tim Shoppa wrote: > > Magnus, were they trying to use the SC-cut crystal itself as a calorimeter, > or something else? > > if using a crystal as a calorimeter (essentially self-temperature probe) to > detect axions, they do not want the crystal cut for

Re: [time-nuts] AN/URQ13 reference AT cut crystal?

Hi > On Feb 17, 2021, at 11:08 AM, Magnus Danielson wrote: > > Hi Tom, > > On 2021-02-17 16:24, Tom Van Baak wrote: >> See pages 20-29 in the Mar-1981 HPJ for the "new SC-cut" 10811 >> article(s): >> >> https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1981-03.pdf >> >> It talks about

Re: [time-nuts] AN/URQ13 reference AT cut crystal?

gards > Paul. > > On Wed, Feb 17, 2021 at 9:31 AM Bob kb8tq wrote: > >> Hi >> >> If it was made before 1981 it pretty much certainly is *not* an SC. That’s >> not to say it is an AT. A lot of crystal cuts got used in OCXO’s over the >> years. >>

Re: [time-nuts] AN/URQ13 reference AT cut crystal?

Hi If it was made before 1981 it pretty much certainly is *not* an SC. That’s not to say it is an AT. A lot of crystal cuts got used in OCXO’s over the years. My guess, it broke, somebody took it apart and threw away the defective crystal. It was replaced with a random unit from the junk box

Re: [time-nuts] AN/URQ13 reference AT cut crystal?

Hi The temperature of the crystal is driven by the oven design. AT / SC / BT / IT or whatever …. it is going to be over 80C. It’s not a function of the crystal. It is what the physics of the oven force you to do. Inner oven *must* be hotter than outer oven. Outer oven *must* be hotter than the

Re: [time-nuts] Looking for help recovering a Spectracom 9383

Hi If your 9383 is running on a >= 15 year old GPS module, that could be a source of trouble. Most of the modules from that era handle the GPS rollover problem poorly. Bob > On Feb 16, 2021, at 10:00 AM, John Miller via time-nuts > wrote: > > Hello Everyone! > > TL;DR: If anyone with a

Re: [time-nuts] The amazing $5 timestamper with 6ns resolution (next stop: 184ps)

Hi You can indeed do some pretty fancy things with easy to get chips !!! If you take a look at JLPCB https://jlcpcb.com They seem to have a range of STM32’s (though not all of them …. :) ) in stock. You can do up an assembled PCB very cheaply through them. One thing

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

things wrong. Interesting as I peel something > like caulking off the outer board I see what looks like a opamp. But its a > FE house number. The top of the can has NSC. The old national semiconductor > label. Could be a LM709 class opamp. > > On Fri, Feb 12, 2021 at 9:12 PM

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

the inner oven simply reading outer oven leakage. Is there a lead I >> can measure the current of the inner oven >> Thanks >> >> On Fri, Feb 12, 2021 at 11:18 AM Bob kb8tq wrote: >> >>> Hi >>> >>> If it’s 105F “outdoors” tha

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

t;> This conversation has given me some good insights. Later today I will >> disable the outer oven. Just curious to see what possible temps might show >> up. Is the inner oven simply reading outer oven leakage. Is there a lead I >> can measure the current of the inner oven &g

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

>>>> 50C is what I have sort of seen over the years. Just wondered could >> there >>>> have been a lower temp version. That made no sense. But then this beast >> has >>>> never made a lot of sense. The $20 mystery from Frequency Electronics.

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

ve been a lower temp version. That made no sense. But then this beast has >> never made a lot of sense. The $20 mystery from Frequency Electronics. >> Thanks Bob >> Paul >> WB8TSL >> >> On Thu, Feb 11, 2021 at 8:08 PM Bob kb8tq wrote: >> >>> Hi

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

eled 1-9. no other clues > to the function. I noticed 2 positions change with warm up. Sort of > supports the 2 oven theory. > Really do not want to take what might be the outer oven off to put the > probe in. > Thanks everyone. > Paul > WB8TSL > > On Thu, Feb 11, 2021 at 5:

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Hi 110 F makes very little sense unless you are in a very cold climate. For military gear (or any gear for that matter) 43C on the oven just doesn’t work. 110 C would make sense in a very high temperature environment. (think of 85C upper end ….). Bob > On Feb 11, 2021, at 2:18 PM, paul swed

Re: [time-nuts] Better than average Rb oscillator

Hi Cool !! > On Feb 10, 2021, at 6:54 PM, Skip Withrow wrote: > > Hello Time-Nuts, > I just finished an almost 27 day run of one of my Rb oscillators and, > at least, I was impressed. > > This oscillator is a stock standard LPRO-101 with only one slight > modification. The 5k C-field pot was

Re: [time-nuts] More Noise Floor Nonsense

h "inherent" noise the counter has. Test with yet another > amplitude/slew-rate and you can refine that estimate and validate it. > > If you want to have fun, try different trigger directions etc. to see > how well calibrated the inputs are. > > Cheers, > Magnus >

[time-nuts] More Noise Floor Nonsense

Hi Back a few years ago, Keysight did one of their PR videos: https://www.youtube.com/watch?v=4DfLkxVe7Lk It shows a fairly simple setup to see what your two channel counter is doing. A lot of counters have a built in standard deviation function

Re: [time-nuts] 5370A

Hi The gotcha with pretty much all HP counters is that the front end chips are non-standard. In some cases they are part of a multi chip module that is non-standard. Option one is to find a parts donor on eBay and transplant the front panel of your 5370, 5334, 5335, 53131,53230 …. and fix it

Re: [time-nuts] AM/PM conversion on mixer, DMTD

Hi In any DMTD setup, isolation between the mixers can be an issue. Proper termination (at least at the RF ports) is important with any mixer if you want to get the rated spec’s. In terms of “who makes the best double balanced mixer?” there used to be a lot of choices. MiniCircuits rarely came

Re: [time-nuts] Some old Time & Frequency stuff for sale, eastern Ontario, Canada

Hi There’s six pretty big gizmos there. My local UPS store would charge me $20 to $30 a box to pack each of them (and barely do an adequate job). Looking up shipping rates from here to there, each of the 6 packages would run about $70 to ship. Net would likely be in the $400 to $600 range.

Re: [time-nuts] Used Hydrogen Maser

Hi > On Feb 6, 2021, at 5:44 PM, Bill Notfaded wrote: > > Let me know when I can buy one please! I'm not kidding. ;^} > This thread has drifted from Hydrogen Masers, to Mercury Ion clocks, to long beam Cs standards, and passes things like 5071’s while doing so. Which of those items are

Re: [time-nuts] Used Hydrogen Maser

Cool !!! > On Feb 6, 2021, at 1:05 PM, Attila Kinali wrote: > > Moin, > > On Wed, 10 Jul 2019 10:55:07 -0700 > "Richard (Rick) Karlquist" wrote: > >> FWIW, about 20 years ago, Len Cutler and Robin Giffard of 5071A fame >> built several Hg ion clocks to be shipped to some govt customer I >>

Re: [time-nuts] Next step after Trimble Thunderbolt

interesting widgets from China. > Regards > Paul > WB8TSL > > > > On Fri, Feb 5, 2021 at 5:24 PM Bob kb8tq wrote: > >> Hi >> >> Be *very* careful how you look at that number from LH. There really >> is no way to know how good ( = how accurate / how

Re: [time-nuts] Next step after Trimble Thunderbolt

Hi Be *very* careful how you look at that number from LH. There really is no way to know how good ( = how accurate / how valid ) it is. It’s a measure of a watch looking at its self. To get something accurate, you would need to compare it to an external device that was at least in low parts in

Re: [time-nuts] Raspberry Pi 4 oscillator replacement

Hi A lot depends on the intended application of the chip. For a general purpose MCU that could go into a wide range of things and that has very few peripherals, 1 to 40 MHz might be just fine. There are chips out there with much wider clock input ranges. Toss in USB and that locks in a clock

Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

x 1”. It mounts to the plate via 4 small screws. Since you have a cable that fits the round connector, wiring it up to this or that should be pretty easy. Yes, the price keeps climbing …. Bob > On Jan 19, 2021, at 2:43 PM, Bob kb8tq wrote: > > Hi > > I don’t know if anyb

Re: [time-nuts] Raspberry Pi 4 oscillator replacement

cess when I > start it and share it here, might be interesting for some. > > On Thu, Feb 4, 2021 at 5:15 PM Bob kb8tq <mailto:kb...@n1k.org>> wrote: > Hi > > Pretty basic approach: > > 1) Get a Rb standard. > > 2) Grab any of the various conversion chips t

Re: [time-nuts] Raspberry Pi 4 oscillator replacement

Hi Pretty basic approach: 1) Get a Rb standard. 2) Grab any of the various conversion chips to take the 10 MHz to 54 (= I don’t know of a standard that puts out 54 MHz). Wire the 10 into it and pull the 54 off of it. (Yes, the chip needs to be programmed and there will be various bits and

Re: [time-nuts] Repair of HP/Agiletn/Symmetricom 5071A Lab Standards

Hi A bit of digging into the error messages probably is in order. The 5071A isn’t great in this regard so you only can get some of the data. There are two basic possibilities: 1) It’s some sort of random failure. Corby is your best bet here. 2) Far more likely, It’s the tube. Cs tubes only

Re: [time-nuts] Need Complete Service Maintenance Manual for HP Agilent 8593EM EMC Analyzer

Hi Based on repairing a couple of the same era analyzers …. It’s a good bet that you have lots / blown the mixer diode in the front end. There are various parts you can replace it with. It’s not brain surgery to do so on the models I have played with ( which does not include the 8593 …). The

Re: [time-nuts] Long Wave Radio-Frequency standard testing

averaging > then proceeds without those values altering the most probable correct average. > > DaveD > >> On Jan 19, 2021, at 08:49, Bob kb8tq wrote: >> >> Hi >> >> The normal approach to filling a gap is to put in a point that is the av

Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

Hi I don’t know if anybody else bought any of these or not. > On Jan 9, 2021, at 10:20 PM, Bob kb8tq wrote: > > Hi > > Just for the sake of listing all the variations: > > https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/3337787

Re: [time-nuts] Long Wave Radio-Frequency standard testing

i, > Yes outliers removal creates gap in Stable32. > The « fill » function can fills gaps with interpolated values. > It does not change much the graphs, except in the low Tau area (see > attached). > Do you know a discussion of impact of outliers removal ? > Gilles. > > &g

Re: [time-nuts] Long Wave Radio-Frequency standard testing

Hi As you throw away samples that are far off the mean, you reduce the sample rate ( or at least create gaps in the record). Dealing with that could be difficult. Bob > On Jan 18, 2021, at 1:33 PM, Gilles Clement wrote: > >> Hi >> >> Very cool !!! >> >> The red trace is obviously the one

Re: [time-nuts] (no subject)

Hi That’s pretty neat !!! At least as I read the posters ( and I could have easily missed something …): Their pulse technique (using the giant telescopes) gives them an instant reading on the distance / delay to the cubesat. Even if there are propagation issues, they are measured (and

Re: [time-nuts] GPSDO won't lock: OCXO aged out?

Hi Ok, what do you know / have a pretty good guess at? 1) There’s an SC (or similar) cut crystal in there 2) That crystal has a curve that looks something like the “0” or “1” curve in figure 7 of: https://coloradocrystal.com/applications/ 3) It

Re: [time-nuts] GPSDO won't lock: OCXO aged out?

> | > > 签名由 网易邮箱大师 定制 > > On 01/16/2021 12:46, Scott Newell wrote: > At 07:49 PM 1/15/2021, Bob kb8tq wrote: >> then indeed, the temperature sensitivity will go >> way up. Most of the OCXO’s off these boards >> are a sub $20 sort of item on eBay. How good

Re: [time-nuts] GPSDO won't lock: OCXO aged out?

Hi Simple answer is to do a general search on eBay for “OCXO” then take a look at the pictures. The descriptions often are a bit off …. Bob > On Jan 15, 2021, at 11:46 PM, Scott Newell wrote: > > At 07:49 PM 1/15/2021, Bob kb8tq wrote: >> then indeed, the temperature sensitiv

Re: [time-nuts] Leakage, tinySA

Hi > On Jan 16, 2021, at 5:32 AM, Hal Murray wrote: > > > My tinySA arrived a few days ago. I'm happy. > > It comes in a nice box with an antenna that extends to a foot, a USB charging > cable (mini, not micro) and a couple of cables. > > It doesn't come with a manual. I haven't found a

Re: [time-nuts] GPSDO won't lock: OCXO aged out?

Hi One of the options is that the EFC has an issue. Another option is that the oven control circuit has a problem. Either one *could* put the center frequency someplace odd. If it’s the heater control (or heater set point) then indeed, the temperature sensitivity will go way up. Most of

Re: [time-nuts] Long Wave Radio-Frequency standard testing

Hi Very cool !!! The red trace is obviously the one to focus on. Some sort of digital loop that only operates under the “known good” conditions would seem to make sense. Thanks for sharing Bob > On Jan 15, 2021, at 9:51 AM, Gilles Clement wrote: > > Hi, > > This is to share current

Re: [time-nuts] CSAC State of Play

PM, Lux, Jim wrote: > > On 1/12/21 3:55 PM, Bob kb8tq wrote: >> Hi >> >> Pretty high up on the list of CSAC projects probably should be locking it up >> to some sort of >> “clean up” oscillator or oscillator chain. > > > In that sense, it's no

Re: [time-nuts] Can a Trimble Thunderbolt cause QRM? Noise can be seen remotely via my SDR.

Hi Best guess is that it’s driving a fairly long un-terminated cable. It could easily have come loose at some point. Indeed there are other possibilities. It depends quite a bit on just what the TBolt is driving … Bob > On Jan 12, 2021, at 6:30 PM, Chris Wilson wrote: > > > > 12/01/2021

Re: [time-nuts] CSAC State of Play

Hi Pretty high up on the list of CSAC projects probably should be locking it up to some sort of “clean up” oscillator or oscillator chain. Yes, there *is* always the CSAC wrist watch :) Bob > On Jan 12, 2021, at 3:58 PM, Nigel gm8pzr via time-nuts > wrote: > > Thanks all for the feedback

Re: [time-nuts] CSAC State of Play

Hi Root cause (as mentioned earlier) seems to be a problem with the seal on the inner “magic guts” of the device. There are units that seem to run on and on forever with no issues, so it’s not a 100% sort of thing. The problem goes back to fairly early CSAC production lots and seems to have

Re: [time-nuts] GPSDO won't lock: OCXO aged out?

Hi The OCXO on the 73090 does not have an internal mechanical trimmer. It is a 0 to 5V tune range. Bob > On Jan 11, 2021, at 8:17 PM, Scott Newell wrote: > > TL, DR: Trimble 73090 5V OCXO won't tune to 10 MHz (9.999 989 MHz at 0 VDC > EFC, 9.999 997 MHz at 4.88 VDC EFC). Worth fixing?

Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

the module off the board has > not been very successful so far. > Regards > Paul > > On Sun, Jan 10, 2021 at 10:03 PM Bob kb8tq wrote: > >> Hi >> >> There appear to be a lot of the cut off boards. The assemblies may well be >> usable “as

Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

d sent me this picture of the back of the cut off > board. Apparently they still have a bunch. > https://www.ebay.com/usr/queen*s_land?ul_noapp=true > > Didier KO4BB > > On Sun, Jan 10, 2021 at 3:47 PM Bob kb8tq wrote: > >> HI >> >> Looking a bit more c

Re: [time-nuts] Negative leap second

Hi I think that the honest answer is that there are *always* systems that get tangled when there is a leap second of any sort. If you dig back a bit on the list there are number of posts talking about abolishing them because of the many difficulties with handling them. One of the reasons

Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

Hi Just for the sake of listing all the variations: https://www.ebay.com/itm/ON-SALE-U-BLOX-ublox-LEA-M8T-0-10-HUAWEI-GPS-Timing-Module-Board/333778776570?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Re: [time-nuts] Ebay Huawei Ublox M8T Modules Warning

Hi The “normal chips” that should be inside the module all have something like a 3.6V max supply rating on them. I would guess that 5V will melt a goodly number of them. Bob > On Jan 9, 2021, at 5:38 PM, Nigel gm8pzr via time-nuts > wrote: > > During the December conversation re LEA-M8T

Re: [time-nuts] small multi-timezone display

Hi > On Jan 7, 2021, at 10:35 PM, Lux, Jim wrote: > > I've got a shelf about 80cm long that I'd like to have 4 timezones displayed > on. > > The obvious easy solution is go buy 4 clocks and put them there. > > But, being a member of this list - anyone know of a off the shelf multizone >

Re: [time-nuts] Rebroadcasting time signals [WAS: La Crosse Clocks - ]

Hi > On Jan 2, 2021, at 8:54 PM, Lux, Jim wrote: > > On 1/2/21 4:31 PM, Bob kb8tq wrote: >> Hi >> >> There is the R-390 and it has a mailing list….. >> >> If you are not running radio, then leakage may not be a problem for you. >> Thus n

Re: [time-nuts] Rebroadcasting time signals [WAS: La Crosse Clocks - ]

Hi There is the R-390 and it has a mailing list….. If you are not running radio, then leakage may not be a problem for you. Thus no need to start hunting for it. Bob > On Jan 2, 2021, at 6:03 PM, Hal Murray wrote: > > Bob kb8tq said: >> If you can hear it on your radio w

Re: [time-nuts] 20th year of time nuts mailing list

Hi Indeed a very Happy New Year to all. Let’s hope that it is *much* happier than 2020 … Thanks very much to Tom and John who put in an enormous amount of work to keep this list running and the interesting place it is. Keep up the good work !!! Bob > On Jan 1, 2021, at 12:02 AM, Tom Van

Re: [time-nuts] Ublox 8T - breakout board

Hi If you are looking at the “raw” output of the uBlox, it is not designed to drive a low impedance. Even if there is a buffer, it may or may not like a low impedance load. Bob > On Dec 31, 2020, at 7:39 PM, Matthias Welwarsky > wrote: > > Happy New Year, Peter. > > If you get the chance,

Re: [time-nuts] Rebroadcasting time signals [WAS: La Crosse Clocks - ]

Hi > On Dec 27, 2020, at 10:30 AM, Tim Shoppa wrote: > > Presumably any "rebroadcast" of WWVB is done in the spirit of near-field > communications where any far-field radiation falls off like 1/r^3 from a > small inductive transmitter loop. > > A loop the size of your entire house would be

Re: [time-nuts] Rebroadcasting time signals [WAS: La Crosse Clocks - ]

Hi If you can hear it on your radio with your normal antenna …. it’s leaking. If you want to track it down, normal radio frequency direction finding techniques work. At 10 MHz a loop or rod antenna is likely your best bet. Bob > On Dec 27, 2020, at 5:05 AM, Hal Murray wrote: > > >

Re: [time-nuts] Hp 10811-60159

Hi Is there actually anything on that carrier board worth keeping? The “normal” approach is to pull the board and wire direct to the OCXO. The carrier board is not needed for normal operation (as long as you supply the correct voltages to the device). I don’t have one in front of me so I

Re: [time-nuts] TECs in cooling below ambient

Hi One of the (many) parts of the EG empire made a dew on the mirror setup and (apparently) sold quite a few of them. It was one of the few gizmos that could reliably tell you about very low temperature (like -50C) dew points. Bob > On Dec 23, 2020, at 8:37 PM, Dana Whitlow wrote: > > The

Re: [time-nuts] TECs in cooling below ambient

Hi I think you will find that things work out a whole lot better if you target something just above room temp. If your room runs 22 +/- 3 C , a set point of 27C likely results in better operation than 17C. Bob > On Dec 23, 2020, at 2:57 PM, ed breya wrote: > > This recent TEC talk reminded

Re: [time-nuts] SMPS or conventional?

Hi Depends very much on what sort of environment it’s in …. Bob > On Dec 21, 2020, at 9:03 PM, Dana Whitlow wrote: > > A properly-tuned PID system does not cycle! > > Dana > > > On Mon, Dec 21, 2020 at 6:49 PM Bob kb8tq wrote: > >> Hi >> >>

Re: [time-nuts] DHS Resilient PNT Conformance Framework

eatest importance here, as that has already improved a lot, but other > properties may dominate. > > Cheers, > Magnus > > On 2020-12-21 20:08, Bob kb8tq wrote: >> Hi >> >> I would guess that out of say 100 OEM’s using a GPSDO, at least 99 of them >

Re: [time-nuts] SMPS or conventional?

Hi Finding a data sheet on a TEC that goes past *very* basic stuff is essentially impossible. The bottom line is that the people who make them very much want to sell them to you. Finding information in those data sheets that suggest problems … not so much. The problem is (mainly) physical.

Re: [time-nuts] DHS Resilient PNT Conformance Framework

that way. Bob > On Dec 21, 2020, at 9:56 AM, Magnus Danielson wrote: > > Hi, > > On 2020-12-21 09:02, Poul-Henning Kamp wrote: >> >> Bob kb8tq writes: >> >>> I have seen cases of “goes away until power cycled”. I have not seen any >&g

Re: [time-nuts] DHS Resilient PNT Conformance Framework

Hi I have seen cases of “goes away until power cycled”. I have not seen any cases of “goes away forever” other than the obvious ( = feed it an insane almanac that prevents if from ever locking up ). Even with that said, I have not seen an example ot that sort of thing living through a hard

Re: [time-nuts] DHS Resilient PNT Conformance Framework

Hi > On Dec 19, 2020, at 8:34 AM, Magnus Danielson wrote: > > Hi Bob, > > On 2020-12-19 00:15, Bob kb8tq wrote: >> Hi >> >> You can always cycle the power … :) > Comes to no relief for some cases, as they store state that keeps them > "killed"

Re: [time-nuts] DHS Resilient PNT Conformance Framework

h JTAG and reprogram it with a flimsy Windows > laptop mid-flight. Right? Right. > > Cheers, > Magnus > > > On 2020-12-17 23:55, Bob kb8tq wrote: >> Hi >> >> Gee, GPS modules that go nuts and stay nuts after getting hit with this or >> that. >>

Re: [time-nuts] DHS Resilient PNT Conformance Framework

it needs vendor intervention. So one learning is that the user > must be able to force the receiver into a "known state". > > Cheers, > Magnus > > On 2020-12-17 19:50, Bob kb8tq wrote: >> Hi >> >> Pretty suspicious looking list of contributors. Very mu

Re: [time-nuts] DHS Resilient PNT Conformance Framework

Hi Pretty suspicious looking list of contributors. Very much so about half way down the list :) …. congratulations !!! ( I guess …) Bob > On Dec 17, 2020, at 12:52 PM, Magnus Danielson wrote: > > Fellow time-nuts, > > DHS just published the work on Resilient PNT Conformance Framework, that >

Re: [time-nuts] Examples of traditional phase noise analyzers

Hi This is probably a more “citation worthy” version of the Fluke App note everybody used: A Test Set for the Accurate Measurement of Phase Noise on High-Quality Signal Sources https://ieeexplore.ieee.org/document/4313904 Bob > On Dec 17, 2020, at 6:02 AM, Attila Kinali wrote: > > Good

Re: [time-nuts] Examples of traditional phase noise analyzers

Hi The “original reference” for doing phase noise was a Fluke app note published back in the late 60’s / early 70’s. Pretty much everybody used it as a starting point when setting up measurements. Just why Fluke came out with the information before HP or GR is one of life’s mysteries …. A

Re: [time-nuts] Repair for HP 5071A Cesium Clock

Hi The usual “best guess” is that the tube has reached end of life. The answer is to send it back to Beverly MA. They will replace the tube and re-adjust the device to work with that tube. The process involves getting a “shipping kit” from them. The device goes back in that box and does so as

Re: [time-nuts] HP105B Help

al arm > 10 MHZ form HP GPSDO to start > Stop is 5 MHz output from HP105B 5MHz > The ADEV is terrible > There is a sawtooth on the Original Phase difference linear residual that > seems very repeatable and may explain the apparent jitter of the output. > > Dave > > >

Re: [time-nuts] HP105B Help

Hi If the inside of the 105 went under water long enough to rust out a lot of parts on the boards, it’s a good bet that the 10811 in the unit got hit pretty hard as well. Simple answer: Spend $40 on an eBay replacement for the 10811. It should just plug in …. Bob > On Dec 13, 2020, at 5:15

Re: [time-nuts] Ublox 8T - breakout board

). No, that’s not a recommendation that one operate that way, only a recognition that a lot of people *do* operate that way. Bob > On Dec 12, 2020, at 11:59 AM, Matthias Welwarsky > wrote: > > On Samstag, 12. Dezember 2020 14:40:11 CET Bob kb8tq wrote: >> Hi >> >>

Re: [time-nuts] Ublox 8T - breakout board

Hi If you are going to drive much with the timepulse output, you will need to buffer it. This is true for just about any practical length of coax. It also applies to other cables once they get past the “few inches” range. Ideally the coax buffer would be something like 4 or so ‘125 buffers in

Re: [time-nuts] Ublox 8T

Hi The LEA footprint is what uBlox sold as “T” variants in previous generations. The NEO footprint is sorta kinda the “consumer” footprint. My guess is that they decided to begin the process of moving everything over to a single footprint. The LEA is there to drop into older designs. The NEO is

Re: [time-nuts] Ublox 8T

e time on the same day I went to order magically they went up $5 > each. I did submit a offer that was rejected. Oh well. > Not that I needed 10 units. :-) > Ones good enough. > Regards > Paul > > On Thu, Dec 10, 2020 at 7:10 PM Bob kb8tq wrote: > >> HI >>

Re: [time-nuts] Ublox 8T

ut might it be a case of removing a neo6 and replacing it with a > 8T? > I have an 8T on order so one way or another will need to do something. > Regards > Paul > WB8TSL > > On Thu, Dec 10, 2020 at 10:31 AM Bob kb8tq wrote: > >> Hi >> >> I’ve looked

Re: [time-nuts] Ublox 8T

; Washington DC area. I got the bare boards from OshPark and you can > order your components from distributors and send them directly to > Small Batch. I preferred using my own parts from known sources, but > they have a stock of components also. > > Regards, > > Mark > > On Th

Re: [time-nuts] Ublox 8T

020, at 2:48 AM, Matthias Welwarsky > wrote: > > On Mittwoch, 9. Dezember 2020 23:58:51 CET Bob kb8tq wrote: >> One note: JLPCB is the only “fab + assembly” outfit I’ve tried. Their boards >> are no better / no worse than a lot of other board fab outfits. I have no >>

Re: [time-nuts] Ublox 8T

B needs just a few more parts, two resistors, a protection chip and a > receptacle. > > >> >> Philip >> >> On Wed, Dec 9, 2020 at 3:27 PM Matthias Welwarsky >> >> wrote: >>> On Mittwoch, 9. Dezember 2020 14:57:55 CET Bob kb8tq wrote: >>>> Hi &

Re: [time-nuts] Ublox 8T

or the less common ones. I then hand solder the connectors on when I > get the boards. > > Philip > > On Wed, Dec 9, 2020 at 3:27 PM Matthias Welwarsky > wrote: > >> On Mittwoch, 9. Dezember 2020 14:57:55 CET Bob kb8tq wrote: >>> Hi >>> >>&g

Re: [time-nuts] Ublox 8T

Hi I think the key point is: *IF* somebody wants to do a layout using the M8T, Bert already *has* a “known good” PCB layout footprint in his inventory of useful stuff. Since the uBlox is a really odd part, you aren’t going to find that footprint built into the standard layout programs. Bob

Re: [time-nuts] HP 5065 Rb update

e mu-metal will likely change over time > due to > physical knocks, changes in orientation of the Rb in the Earth's field, > temperature > changes, etc, all of which will make the Rb less stable than it could be. > > Dana > > > On Mon, Dec 7, 2020 at 6:18 PM Bob kb8tq wrot

Re: [time-nuts] HP 5065 Rb update

Hi The existing c field winding is *inside* the magnetic shield on the physics package. Simply getting a second winding inside that package involves some (scary to most of us) tearing apart (an re-assembly) of the physics package. Next up, the mag field needs to be reasonably uniform. That

Re: [time-nuts] HP 5065 Rb update

Hi What we are dealing with here is a transistor circuit that does indeed need the low value pot. It also needs to beL *very* stable. Lots of details on just how stable at: HP5065A Bob > On Dec 5, 2020, at 4:37 PM, ed breya wrote: > > Paul, if the pot

Re: [time-nuts] HP 5065 Rb update

Hi Crazy as it seems, running at a higher C Field current makes the device more sensitive to stray mag field. If you want to “soup up” your 5065, you would adjust the synthesizer for minimum (but still in range) C Field current. Why not go to zero ( or real close to it) ? There are multiple

Re: [time-nuts] HP5061 Cesium ion pump question

Hi Having watched a number of Cs tubes die ….. Measuring ADEV on your Cs is a good idea. As the tube goes downhill the signal to noise often gets worse. This shows up even at relatively short tau ADEV ( like 100 to 1000 seconds). On a 5061 era device, this means doing ADEV at the 1x10^-11 to

Re: [time-nuts] HP5065a cfield issue

ing. But it did not seem to > impact the the cesiums or many many other pieces of equipment. > The 5065 is still super stable. > Regards > Paul > > > > On Thu, Dec 3, 2020 at 11:57 AM Bob kb8tq wrote: > >> Hi >> >> I don’t believe that the quantum transiti

Re: [time-nuts] HP5065a cfield issue

Hi I don’t believe that the quantum transitions are sensitive enough to minor temperature shifts to account for a 1 or 2 ppb sort of shift….. Magnetic field, ( giant magnetic play toy moved next to Rb … ) yes that will do the trick, but temperature … tough to do … Everything I can find

Re: [time-nuts] HP5065a cfield issue

numbers from memory 3 seconds for 5ns drift and the units slow. Will > confirm and reshare. > Regards > Paul. > > > On Wed, Dec 2, 2020 at 2:52 PM Bob kb8tq wrote: > >> Hi >> >> Just double checking….. Are we still after a change went past 1/3 of the >>

Re: [time-nuts] HP5065a cfield issue

Hi Just double checking….. Are we still after a change went past 1/3 of the pot range? Can we get the pot back to the original location and measure the frequency offset (even if only in a crude fashion)? Best guess is still that this should be a ppb or more of shift. If it’s down in the

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