Re: [time-nuts] eLORAN in the Antipodes ? (was: Re: eLORAN will be on the air GRI 99600)

Hi Back in the day, if you hung out for a while in the lobby at Continental Electronics, you would notice a model of an old style transmitter over by one wall. Go over and look a it for a a while and all the usual parts were there. Couple of big tubes, big matching coil insulators here and

Re: [time-nuts] eLORAN in the Antipodes ? (was: Re: eLORAN will be on the air GRI 99600)

in a large garage. The antenna matching gear at the base of one of the antennas …. no way. It’s closer to the size of a small house. Of course as VLF stations go, WWVB is “low power”. Same basic issue, lots of weird interactions and a need to keep the signal very precise. Not as easy as it m

Re: [time-nuts] eLORAN in the Antipodes ? (was: Re: eLORAN will be on the air GRI 99600)

Hi > On Aug 8, 2020, at 7:18 PM, Bill Byrom wrote: > > Yes, the weather can change the phase of the transmitted antenna signal > unless corrections are performed. From the WWVB (60 kHz VLF time/frequency > station at NIST in Fort Collins, CO) website at >

Re: [time-nuts] eLORAN in the Antipodes ? (was: Re: eLORAN will be on the air GRI 99600)

Hi > On Aug 8, 2020, at 4:15 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> Same basic issue, lots of weird interactions and a need to keep the signal >> very precise. Not as easy as it might seem. > > What does "precise" mean in that context? > > I'm not an antenna-nut. Can an

Re: [time-nuts] eLORAN in the Antipodes ? (was: Re: eLORAN will be on the air GRI 99600)

Hi The main point is: If you are looking at a VLF system, phase matters a lot. If your objective is a 100 ns @ 1 second sort of accuracy, you need a very stable phase. At 100 KHz, you are looking at 3.6 degrees of phase shift. Go down to 60 KHz and you are right at 2 degrees. Head to Omega sort

Re: [time-nuts] Satelles PNT from Iridium satellites

Hi > On Aug 9, 2020, at 7:03 PM, Tom Van Baak wrote: > > Hi Stu, > > There's no problem with a semi-commercial posting here. You've been a member > for a decade and frequent contributor plus the subject matter is exactly > on-topic. So thanks for posting. > > I spent a while on your web

Re: [time-nuts] WWVB PM Time Questions

Hi Backing up a bit ….. The WWVB modulation is *very* predictable. Once you have lock, you can guess just about every phase reversal you will see. If you have an “approximate lock” ( = a time pre-load that is within a few seconds) you can guess a lot of them. (There were a few aux data bits

Re: [time-nuts] WWVB PM Time Questions

Hi It also *very* much depends on the stability of your local reference and the stability of the ionosphere. Unless both are “pretty darn good” a hundred second integration is utter nonsense Bob > On Jul 31, 2020, at 5:00 PM, Poul-Henning Kamp wrote: > > -------- > Bob

Re: [time-nuts] WWVB SDR discussion

many > nights. > Enjoying the thread. > Regards > Paul. > > On Tue, Aug 11, 2020 at 7:45 PM John Magliacane via time-nuts < > time-nuts@lists.febo.com> wrote: > >> On Tuesday, August 11, 2020, 07:14:12 PM EDT, Bob kb8tq >> wrote: >> >>&g

Re: [time-nuts] Oscillatek 2352

Hi Oscillatek was acquired by K in the early 1980’s. K was acquired by Dover in the mid 1980’s. Dover acquired Vectron Labs in the early 1990’s. All data on the Oscillatek parts is long gone …. even to the person who ran the company ( = me ) …. Simple answer: Hook up a power supply and

Re: [time-nuts] ! PPS Source

Hi Here’s the “whole story”, sorry if it repeats things you already know … All GPS modules that I have ever seen use a free running clock. The internal oscillator is *not* locked to GPS. When they want to generate a 1 pps output they drop / add cycles from the the internal oscillator to get it

Re: [time-nuts] ! PPS Source

id > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob > kb8tq > Sent: 13 August 2020 14:39 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] ! PPS Source > > Hi > > Here’s t

Re: [time-nuts] ! PPS Source

Hi > On Aug 13, 2020, at 6:35 PM, ed breya wrote: > > I have often wondered about all this sawtooth correction stuff, and I think > I've asked here too, but never got a definitive answer. Every time this comes > up, there are all sorts of explanations of the characteristic, and inevitably >

Re: [time-nuts] "The Penultimate HP5065 A15"

Hi > On Aug 5, 2020, at 2:55 AM, tim...@timeok.it wrote: > > > I would like to share with you my thoughts on two important points that > concern a little all attempts to modify and upgrade the equipment. > > In general I am very reluctant to modify both the electrically and >

Re: [time-nuts] WWVB SDR discussion

Hi As long as you sample “fast enough”, you can recover phase. Indeed, even if you sub-sample (sample to slow), you can still get phase back with a few relatively minor constraints. Since one of those is “don’t sub sample at exactly a fraction of the carrier”, a sub-sample “locked” receiver

Re: [time-nuts] low power divide by 5

Hi For vacuum tube divide by 5 / 10 circuits, take a look at the schematics of the Beckman EPUT meters….. Bob > On Jul 2, 2020, at 9:48 AM, Tom Van Baak wrote: > > > I'm surprised nobody has suggested using the 12AX7 or 6J6 dual triodes. > > Jim, > > Funny, just yesterday I was looking at

Re: [time-nuts] 1PPS questions

Hi Probably the easiest approach is an L pad at the input to the measurement device. Something like a 470 ohm in series and a 120 ohm to ground. A 50 ohm pad may not make the line driver in the source device very happy …. Something more exotic would be to do a distribution amp. Use a NC7SZ125

Re: [time-nuts] 30 MHz freq adjust by Hz

Hi There is a NIST paper (somewhere) that has an example of doing this. Like any image reject mixer approach, it only does just so well. It’s no different than generating SSB the same way. You get a spur that is 40 to 60 db down at the “image” frequency. You can tweak this or that to get it

Re: [time-nuts] low power divide by 5

Hi > On Jul 2, 2020, at 5:30 PM, jimlux wrote: > > On 7/2/20 11:37 AM, ed breya wrote: >> It's been fun reminiscing about all these dividers and techniques, but >> getting back to the OP, the original search was for a divide by 5 with "low >> power" and operation from 5 to possibly 3.3V, and

Re: [time-nuts] low power divide by 5

Hi > On Jul 2, 2020, at 2:34 PM, Hal Murray wrote: > > >> Funny, just yesterday I was looking at the design of a laboratory cesium >> beam standard from 1963. Sorry, there's no divide-by-5 example in there. But >> the attached images show the 108x multiplier (8.5 MHz to 9180 MHz). Sure >>

Re: [time-nuts] Raspberry Pi NTP server

Hi > On Jul 6, 2020, at 11:43 AM, Matthias Welwarsky > wrote: > > On Samstag, 4. Juli 2020 16:49:11 CEST David J Taylor via time-nuts wrote: > >> Matthias, my feeling is that if you want a precision source, neither BB not >> the RPi is a good solution. Maybe with all the tweak you

Re: [time-nuts] Raspberry Pi NTP server

Hi > On Jul 14, 2020, at 6:13 PM, Trent Piepho wrote: > > On Mon, Jul 13, 2020 at 4:52 PM Hal Murray wrote: >>> Is there any way for a USB device to synchronise with the CPU clock (perhaps >>> via the USB framing) so that a special-purpose device could timestamp the >>> PPS >>> occurrence

Re: [time-nuts] low power divide by 5

Hi > On Jul 2, 2020, at 6:38 PM, jimlux wrote: > > On 7/2/20 2:50 PM, Bob kb8tq wrote: >> Hi >>> On Jul 2, 2020, at 5:30 PM, jimlux wrote: >>> >>> On 7/2/20 11:37 AM, ed breya wrote: >>>> It's been fun reminiscing about all these div

Re: [time-nuts] PDIP package 100 MHz decade dividers

Hi HC is the *slower* version of AC. If it makes it to 50 MHz, you are doing well ….. Bob > On Jul 11, 2020, at 6:00 PM, Perry Sandeen via time-nuts > wrote: > > Learned List, > On previous posts I was looking for a PDIP package 100 MHz decade divider. > Reading just the front of the data

Re: [time-nuts] HP 5316B External Reference

Hi The “typical” HP counter for many decades has phase locked an internal oscillator to the external reference. I have not seen any designs that use injection locking. Given the somewhat crazy math associated with injection locking, this is not a big surprise. By modern standards the 5316 is

Re: [time-nuts] 30 MHz freq adjust by Hz

erators after my years in SDR... > > g > > On 2/07/2020 12:14 am, Bob kb8tq wrote: >> Hi >> >> There is a NIST paper (somewhere) that has an example of doing this. Like >> any image >> reject mixer approach, it only does just so well. It’s no di

Re: [time-nuts] 30 MHz freq adjust by Hz

gt; suppression. in this case, it is just single freq quadrature at 30 Mhz I > need to generate. We will see ! > > cheers > > > > On 02/07/2020 09:40, Bob kb8tq wrote: >> Hi >> >> The same “small fraction of a degree” and “small fraction of a db” issues

Re: [time-nuts] 5071A

Hi My recollection is that if power is cycled, it drops out of “continuous operation mode”. There *might* even be BBC footage documenting this … :) Simply put, all of these devices ( 5071 and the other HP atomic standards I have seen) *only* go into continuous operation when you push a button.

Re: [time-nuts] PPS stats

Hi Do you have any other inputs into your server? NTP compares the various inputs to come up with things like stability. With nothing to compare to, there is no data to show. Bob > On Jul 6, 2020, at 12:04 PM, Keith E. Brandt, WD9GET wrote: > > I have finally got my RPi NTP server set up

Re: [time-nuts] Frequency division by 81

; GC > >> Le 21 juin 2020 à 05:49, Bob kb8tq a écrit : >> >> Hi >> >> *Any* divide approach followed by a flip flop clocked by the input clock >> will meet >> that same basic requirement. While it *sounds* like it would improve things, >> i

Re: [time-nuts] Frequency division by 81

Hi *Any* divide approach followed by a flip flop clocked by the input clock will meet that same basic requirement. While it *sounds* like it would improve things, it very much depends on the details. What are you trying to do? What is the input frequency? What is the phase noise requirement?

Re: [time-nuts] Vibration isolation of quartz oscillators

Hi First thing to find out is what the per axis sensitivities of your oscillators are. There should be significant variation between the three directions. What you find on one may or may not be what you find on the rest. Just about any source of (single directional) vibration will work for this

Re: [time-nuts] Vibration isolation of quartz oscillators

Hi Accelerometer compensation of OCXO’s is indeed possible. There are parts out there that will do the job. Phase shift is your enemy in this case. You are trying to get two AC signals to sum to zero. Fairly small phase shifts will limit the “floor” of a process like this. Mounting the

Re: [time-nuts] Frequency division by 81

Hi What are we trying to do here? What is the input frequency? What is the phase noise of the OCXO? What is the phase noise requirement on the output? Are there other system based requirements on the output? (ADEV maybe ….) = Symmetry (by it’s self) going from 50/50 to 45/55 (or

Re: [time-nuts] Frequency division by 81

Hi The biggest issue is that there are so many variables. They never seem to get nailed down. What you are seeing is the answer to 20 or more “niche” requirements. For instance: Is the “phase noise” requirement close in or broadband? ECL is in general horrible for broadband phase noise. Is

Re: [time-nuts] Frequency division by 81

>> https://dabbledoo.weebly.com/halcyon-ofs-1.html >> >> If you live very close to the transmitter site, it may work to condition and >> then divide the 162 kHz signal, but if not, you will not be happy. >> >> Best regards >> Ole >> >>> Den 21-06-202

Re: [time-nuts] Frequency division by 81

Hi A lot depends on the output frequency of your OCXO. If it puts out 900 MHz, that’s a bit different than if it puts out 9 MHz. For “normal” OCXO’s in the sub 30 MHz region, CMOS logic will do the division just fine. If a PICDIV is a candidate, I’m guessing the OCXO is in this range. You

Re: [time-nuts] Frequency division by 81

Hi The gotcha is that the “HC” logic families have pretty high broadband noise floors compared to newer parts. At 20 log (N), divide by 81 gets you about 38 db of phase noise improvement. If you started off at -130 dbc/Hz, you come out at -168 dbc / Hz. That (of course) assumes you don’t hit

Re: [time-nuts] Vibration isolation of quartz oscillators

Hi There are tables made for low vibration test setups. They are (essentially) a big heavy cast iron table sitting on air cushions under each of the legs. Not a great approach for a low G OCXO …. Bob > On Jun 27, 2020, at 8:09 PM, Neville Michie wrote: > > An old trick I learned from an

Re: [time-nuts] Problems with Lady Heather and Asus Aspire A515-55 laptop with an HP 58503A GPS receiver

Hi Having done *exactly* the same thing a while back: Be very careful about what the “to” address is when you try to do a private message. The headers get populated with the TimeNuts email address. It’s not as easy to do an off list reply as it seems …. Bob > On Jun 7, 2020, at 5:48 PM,

Re: [time-nuts] ThunderBolt question

Hi Do a little research and You will find that a 3 db noise figure is as good as it gets with a receiver who’s front end is a perfect match to the transmission line …. (Signal goes down 6 db when you match, noise drops by 3 db ….). Unless you are using some sort of ferrite isolator on the

Re: [time-nuts] ThunderBolt question

Hi A “cable echo” looks like any other multi-path signal. Your local environment provides *lots* of those all the time. That's regardless of how hard you try to get rid of them. If they are *stronger* than the main signal (which they can be in a “bounce off a building" case) they really mess

Re: [time-nuts] ThunderBolt question

Hi Their engineering group also backs up this statement if you ask them about it face to face. The answer that comes back is: “We ran a bunch of tests with 75 and 50 ohm cable, we could see no difference in the results”. Bob > On Jun 6, 2020, at 1:30 PM, Taka Kamiya via time-nuts > wrote: >

Re: [time-nuts] Trigger circuit for TIC

Hi (wandering a long way away from the original post …..) When you design a DMTD that runs into a counter, by far the biggest part of the DMTD design is the limiter(s) that turn the mixer output into a “useable” square wave. Even high end commercial counters are unable to process the output of a

Re: [time-nuts] Tale of Two GPStars...

Hi Ok, let’s put some numbers on this. What goes into your typical “Rb GPSDO” gizmo is a telecom Rb. They normally start off around 2x10^-11at 1 second. They drop by the square root of tau as you go on out. Indeed the PRS-10 has an odd bump in the 1 to 10 second range, there is an exception

Re: [time-nuts] Interesting application for really nutty timing

Hi Back in the 1970’s this was a fun dinner conversation with the JPL guys. It always seemed to end up with “in a year or two we’ll have it worked out ….” Bob > On Jun 2, 2020, at 5:49 PM, Hal Murray wrote: > > I watched the video of an astronomy talk yesterday. (Info below. I thought >

Re: [time-nuts] WWVB PM Time Questions

His unit was not an oven as I recall. >> Just maybe a bit too good was actually bad. >> Hard to say and no time to play right now. >> Regards >> Paul >> WB8TSL >> >> On Wed, Jul 22, 2020 at 6:06 PM Bob kb8tq wrote: >> >>> Hi >>> >

Re: [time-nuts] 3D printed tourbillon clock

Hi Very cool !! I’m guessing a couple hundred hours to print the parts and maybe the same sort of time to clean them all / fit them together ….. Bob > On Jul 25, 2020, at 2:40 AM, Mark Sims wrote: > > https://www.youtube.com/watch?v=E9prY3ky6Bo >

Re: [time-nuts] 3D printed tourbillon clock

; > > > Link to STL files: > > > > https://www.myminifactory.com/object/3d-print-tourbillon-mechanica-tourbillon-escapement-mechanical-clock-assembly-guide-pdf-in-description-124938 > > > > Approximate run-time on PETG spring: 10 minutes > > Total Print Ti

Re: [time-nuts] PDIP package 100 MHz decade dividers

Hi If you want to get the 74AC74 (or better the 74LVC74) running it’s best: 1) Power it off of 5.50V 2) Transform the drive signal so that it presents 5.5 to 5.8V p-p to the gate input. 3) Bias the AC signal so that it swings from about 0 to 5.5V Bob > On Jul 19, 2020, at 8:18 AM, Magnus

Re: [time-nuts] WWVB PM Time Questions

Hi > On Jul 22, 2020, at 3:51 PM, paul swed wrote: > > Ray watch out for my comment on the KD2BD solution. That oscillator isn't > available and I have not been able to map something else into it. Tried > several good grade Oven oscillators. Just be aware of that issue. > Would need to do

Re: [time-nuts] Double balanced mixer question

Hi Mixing those two frequencies *should* give you 10.01 MHz and 1 Hz at equal levels. Any amplitude inequality will be due to filtering. Feed two tones like that into various amps and you will drive them into compression. You need a good linear amp to handle both at once. Indeed some form

Re: [time-nuts] WWVB PM Time Questions

I am dealing with is an efc range control issue. > Perhaps the swing is to large... > Regards > Paul > WB8TSL > > On Thu, Jul 23, 2020 at 8:58 AM Bob kb8tq wrote: > >> Hi >> >> 10 MHz *is* a frequency at which you can find a pretty good $3 to $6 OCXO. >>

Re: [time-nuts] WWVB PM Time Questions

Hi > On Jul 30, 2020, at 5:11 PM, Hal Murray wrote: > > >> I'm sure there are a lot of transistors in their IC to handle all the phase >> tracking and time decoding. > > They aren't doing phase tracking, just decoding time data. All that crap > about Atomic Time is just advertising BS. > >

Re: [time-nuts] sub harmonic VCO locking

Hi > On Jul 30, 2020, at 7:56 AM, glen english LIST > wrote: > > Before I commit the soldering iron, can anyone share their sub-harmonic > injection locking experiences ? > > I have to make 393.216 from 49.152 . > Yes, lots of ways I know. > > injection locked at 1/8 of the frequency

Re: [time-nuts] WWVB PM Time Questions

Hi > On Jul 30, 2020, at 3:01 PM, rcb...@atcelectronics.com wrote: > > So the $64 million dollar question is this. How do the La Crosse > distributors sell the ULTRATOMIC clock for $35-$40. That means La > Crosse's manufacturing cost is probably around $15-$20. Building a > million clocks would

Re: [time-nuts] PDIP package 100 MHz decade dividers

Hi One very simple “fix” for the low voltage sine wave: Put in an L network and transform the load output to a higher impedance. Voltage goes up as square root of impedance change. For modest (2X ~ 4X) voltage changes, the lowpass L network still has modest Q and low component sensitivities.

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] 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] 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] 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] 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] Well priced GPSDO that outputs IRIG-B

Hi My concern would be the level of documentation that comes with the part. There are (obviously) a lot of external connections required to get it to do all they claim. I would think that documenting all that variability would be a fairly involved task …. It’s also not quite clear if there is

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] 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] 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] 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

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] SMPS or conventional?

AE%B1bd4kc%40126.com%22%5D>签名由 > 网易邮箱大师 <https://mail.163.com/dashi/dlpro.html?from=mail88> 定制 > > On 11/23/2020 22:15, Bob kb8tq <mailto:kb...@n1k.org> wrote: > Hi > > There are two “zones” in the typical Rb physics package. They both need to be > hea

Re: [time-nuts] SMPS or conventional?

Hi There are two “zones” in the typical Rb physics package. They both need to be heated. Unfortunately they need to be heated to *different* temperatures. This makes for an interesting design. Insulate things to well and the one that is supposed to be at a slightly lower temperature is heated

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] 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

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

; 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] EOL Motorola Oncore Remote Antenna

Hi You are going to fabricate the “base” as a solid piece. Getting a coax style connector into that is just a matter of your credit limit. The larger issue on the device is making the “cover” out of metal. That probably isn’t going to work very well :) Now you are off into a glass cover of

Re: [time-nuts] EOL Motorola Oncore Remote Antenna

Hi The gotcha with the device in question is that roughly 90% of the volume is in the microwave path to the antenna. Most of the remaining 10% if filled with electronics …. One (as yet unmentioned) solution is to equip the device with an air inlet *and* a small bleed hole. You

Re: [time-nuts] HP5065a cfield issue

. All sorts of things > can drift with this setup. > Will use a 5371b counter later tonight and get serious. > But that said have I actually lost a bit in the synthesizer. In the > diagrams, looks like diodes and other ancient devices to consider. > Regards > Paul > > On Tue, Dec 1

Re: [time-nuts] HP5065a cfield issue

Hi …… the synth output comes right out of the BNC on the front panel. Pretty easy to hook a counter to. Also a good place to feed in an external synth. Bob > On Dec 1, 2020, at 2:11 PM, paul swed wrote: > > Corby I like the 3325 suggestion. I have a 3335 that I can lock together > with

Re: [time-nuts] Early Christmas - DMTD up and running

Hi When doing DMTD “noise floor” with a common oscillator, you need to use a “line stretcher” between the inputs to the DMTD. In the case of a 5 MHz system, you would need about 30 to 50’ of coax to get the job done. There is no need for infinitely fine steps, a set of 3 cables at 20 / 10 / 5

Re: [time-nuts] HP5065a cfield issue

measurements. Will have to look them up. > Regards > Paul. > > On Tue, Dec 1, 2020 at 8:51 AM Bob kb8tq wrote: > >> Hi >> >> The C field coil resistance is low enough that you have something in the >> vicinity >> of 10mv across it. If you want to c

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] Voyager space probe question

Hi The Voyger probes are very complex setups. There are a *lot* of frequency references in them. The “on the ground” rover happens to have used a Vectron TCXO …. Bob > On Nov 28, 2020, at 5:06 PM, donald collie wrote: > > Can any group member describe the onboard frequency reference[s] used

Re: [time-nuts] HP5065a cfield issue

Hi The C field coil resistance is low enough that you have something in the vicinity of 10mv across it. If you want to check the C field regulator, I’d just pop a wire and put a meter in series with the coil. My bet: your synthesizer has slipped a bit somewhere. I’d check it’s output against

Re: [time-nuts] HP5065a cfield issue

Hi Ok, if the synth is off the “suspect” list …. *and* it’s a good solid lock. Back to the C field. If it jumped 4x10^-11, that’s a very different thing than jumping 2x10^-9. Finding the “source” of a 0.04 ppb shift is going to be a lot harder than finding a 2 ppb gotcha. Best to nail down

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

Re: [time-nuts] EOL Motorola Oncore Remote Antenna

Hi > On Nov 30, 2020, at 6:08 PM, jimlux wrote: > > On 11/30/20 1:22 PM, Art Sepin wrote: >>> To me it looks more like water ingress through micro-cracks in the >>> plastic-dome, and the O-ring did its job and kept that water in. >> Interesting. That's the first we've heard about micro-cracks

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] 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] 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] 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 - 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

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] 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] 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

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 >

<    5   6   7   8   9   10   11   12   13   14   >