Re: [time-nuts] Assistance needed to understand some V_OCXO stability concepts.

hould* be taken out by the GPSDO function …. Things that take minutes (or maybe an hour) are what will make things messy. Drafts and other transient temperature effects are the target here. Bob > > Regards > Joe > > > On Sat, Oct 17, 2020 at 6:54 PM Bob kb8tq wrote: > >>

Re: [time-nuts] cheap frequency extension for timepod

Hi I would *think* that the phase noise out of the down converter channel would be the DUT + LO. If indeed you have DUT A + LO B and DUT C + LO D, you then have a lot of A + B vs C + D stuff to sort out …. Bob > On Oct 17, 2020, at 2:48 PM, John Ackermann N8UR wrote: > > FWIW, I have done

Re: [time-nuts] Droitwich Frequency Error

Hi > On Oct 18, 2020, at 10:07 AM, Andy Talbot wrote: > > Hi Folks > I've just joined this list, but have had an interest in accurate frequency > measurement for decades, ever since finding a fully operational HP5061A in > skip with what appears to be plenty of Cs life left in the tube. It

Re: [time-nuts] SMPS or conventional?

Hi What will the output of the box be used for? If low phase noise is an objective, then one needs to be pretty careful about power supply noise. If low phase noise is not a “need” in this case, then (good) switchers can be used for everything. What’s a “good” switcher? You want one that is

Re: [time-nuts] WWVB Dephaser Question

M, John C. Westmoreland, P.E. > wrote: > > Bob, > > Thanks for the answer; but does anyone actually have a documented > specification posted for one of these 'massive' WWVB 60kHz antennas > someplace? > > Thanks. > > 73's, > John > AJ6BC > > &

Re: [time-nuts] WWVB Dephaser Question

o that option is out. I haven't > made a decision on the CPU yet. I will just use whatever it takes for > the job, probably a STM32 part of some sort. I have a couple of STM32 > development boards I can use when I get to that point. > > Ray > > > Original Message --

Re: [time-nuts] WWVB Dephaser Question

ata > for my CPU to process and send to a display. > > I already have a GPS based clock that I built so I thought the WWVB > phase clock would be an interesting project. > > Ray > > Original Message ---- > Subject: Re: [time-nuts] WWVB Dephaser Qu

Re: [time-nuts] WWVB Dephaser Question

E. < >> j...@westmorelandengineering.com> wrote: >> >>> Bob, >>> >>> Thanks for the answer; but does anyone actually have a documented >>> specification posted for one of these 'massive' WWVB 60kHz antennas >>> someplace? >>> >&g

Re: [time-nuts] What's available in the way of DSP for new WWVB?

Hi For a full setup, you could do it a lot of ways. A setup of: Antenna -> front end -> ADC -> MCU -> D/A would be one approach. Various bits like a local clock also would get into the design. There are *many* other approaches. == There are a lot of D/A’s that will clock in the 100’s

Re: [time-nuts] WWVB Dephaser Question

time-nuts group. >> As they say have fun. >> Regards >> Paul. >> WB8TSL >> >> On Thu, Oct 8, 2020 at 5:39 PM wrote: >> >>> Bob, >>> >>> I am using a ferrite rod antenna for the receiver. No outside antenna. >>>

Re: [time-nuts] Aging 5065A ?

Hi Well….. the existing synth in the 5065 is no champion spur wise. Coming up with a DDS that is “as good as” is not all that crazy. The 5 MHz reference is multiplied to 6.x GHz and then mixed with the synth. The close in phase noise of the multiplied signal is mixed with the synth. The

Re: [time-nuts] Experiment in lowering the TAPR TICC noise floor

Hi > On Oct 7, 2020, at 4:25 PM, John Ackermann N8UR wrote: > > Hi Attila -- > > Just a couple of corrections -- the "coarse clock" in the TICC runs at 10 kHz > (100 us), not 1 kHz, and therefore the TDC never sees a measurement interval > longer than 100 us, not 1 ms. > > More importantly,

Re: [time-nuts] Aging 5065A ?

he length of the accumulator. What about the D/A > then? 73 - Mike > > Mike B. Feher, N4FS > 89 Arnold Blvd. > Howell NJ 07731 > 848-245-9115 > > -Original Message- > From: time-nuts On Behalf Of Bob kb8tq > Sent: Wednesday, October 7, 2020 1:55 PM > To: Discussion

Re: [time-nuts] Aging 5065A ?

Hi Replacing the synthesizer with something more modern is certainly possible. I have a project (slowly moving along) to do just that. There is nothing crazy on the logic board, it could easily be replaced with something more modern for not a lot of money. The phase detector / photo amp /

Re: [time-nuts] Spectracom 8161 "Standard Frequency Receiver - Oscillator" for WWVB (and question...)

Hi The height of the ionosphere changes night to day. That changes the effective propagation distance. As the day/night (or night/day) transition point crosses the path between you and WWVB the two “modes” compete with each other. They can do fun stuff like cancel out the signal entirely. If

Re: [time-nuts] WWVB Dephaser Question

Hi The “simple” approach is to generate the full modulation pattern for the signal based on a “known good” time source. There are a couple of ambiguous bits so it will only be close. Feed that into your inverter and the result will be (near) clean WWVB. Since you never demodulate the WWVB,

Re: [time-nuts] Time and tide - pendulum clocks and gravity tides

Hi Isn’t there a picture of TVB doing something to that clock? :) Bob > On Oct 19, 2020, at 5:30 PM, Hal Murray wrote: > > Speaking of pendulums... > > BBC: The Clock That Changed the World (BBC History of the World) > https://www.youtube.com/watch?v=T-g27KS0yiY > 29 minutes > > Fantastic

Re: [time-nuts] Assistance needed to understand some V_OCXO stability concepts.

XCO - 101' experience levels, but > thanks for the help! No problem …. happy to help. Bob > > Thanks again! > Regards > Joe > > On Sun, Oct 18, 2020 at 12:31 AM Bob kb8tq wrote: > >> Hi >> >> (see below) >> >>> On Oct 17, 2020, at 4:

Re: [time-nuts] ! PPS Source

Hi Keep in mind that a GPS receiver is *very* sensitive to close in phase noise on the clock source. If you dig into the data sheets on the chip sets, they are quite explicit about this. Any approach you use to steer the TCXO will need to be very quiet. Next, the internal firmware *assumes*

Re: [time-nuts] Looking for specs for a Matsushita CCA532ST02 GPS antenna

Hi > On Aug 28, 2020, at 7:11 PM, Scott Armstrong wrote: > > Hi all, > > I have a Matsushita CCA532ST02 GPS antenna that has been sitting in a parts > box in the garage probably for the past 20 years. > I've done a few searches on the web for specs but have come up empty. I > believe this GPS

Re: [time-nuts] Datasheet for TeleQuarz 20TQG01?

Hi Regardless of who made it, OCXO’s often don’t do well after being knocked around. The process of puling them off pcb’s is stressful to the internals. The shock and vibration in normal “junk box” storage can be an issue. As a result, the original performance data may not be of much use.

Re: [time-nuts] Dead 5065A - Some comments - Some questions... (III)

Hi Unless you are going to dig in and rebuild the microwave part of the physics package, you are limited in terms of what you can or can’t do. The SRD setup seems to be a bit unique in the 5065 so messing with it probably isn’t a good idea. Common wisdom is that there is a filter in the

Re: [time-nuts] Dead 5065A - Some comments - Some questions... (III)

Hi > On Aug 27, 2020, at 10:35 AM, Poul-Henning Kamp wrote: > > -------- > Bob kb8tq writes: > >> Common wisdom is that there is a filter in the cavity match that >> is specific to 60 MHz. Putting in 120 MHz apparently does not work >> well. I haven’t tried it

Re: [time-nuts] time-nuts Digest, Vol 193, Issue 36

Hi Normally the parts I am looking at are the run of the mill eBay parts. They are < 10 years old, but have been on boards. It is rare that they will not tune to frequency (if they have output ….). My guess is that the typical modern OCXO is good for 20+ years before they age out of spec. Bob

Re: [time-nuts] What do people use for measuring temperature?

Hi You would need to find a temperature sensor rather than a voltage reference…. :) The AD590 still seems to be considered a pretty good device after all these years. If there is long term data in the spec sheet, I did not spot it in a quick read. Based on what we saw back in the 1970’s (which

Re: [time-nuts] What do people use for meassuring temperature?

tor-terminology/stability.aspx >> >> <https://www.littelfuse.com/technical-resources/technical-centers/temperature-sensors/thermistor-info/thermistor-terminology/stability.aspx> >> >> >> >> Bruce >> >>> On 27 September 2020 at 11:15 Bob kb8tq &

Re: [time-nuts] What do people use for measuring temperature?

Hi > On Sep 27, 2020, at 11:59 AM, Jeremy Nichols wrote: > >> >> >> >>> We used three thermistors and averaged them. >> >> I assume they were spread around in case one side of the package was >> warmer than the other. >> > >> Could one do an analog “average” by using a set of, for

Re: [time-nuts] HP Z3805A internal PSU questions

Hi Trace around the input filter. There are coils there that may go open. There are also a couple of board mount fuses that pop from time to time. Bob > On Sep 29, 2020, at 8:07 AM, Tim Tuck wrote: > > And as soon as I posted this I found what I was looking for on KO4BB's > website - I

Re: [time-nuts] Help needed with frequency standard

Hi You have a lot of stuff that runs off of GPS L1. Any “common mode” issues (like ionospheric disturbances) will propagate into all of them. What impact that has on each one is very much a “that depends” sort of thing. The firmware and filtering quickly get into the act …. They all will wander,

Re: [time-nuts] What do people use for measuring temperature?

Hi The gotcha with *any* SMT part is that stress / strain from the soldering process gets into the performance of the part for a *long* time. There is no mechanical “buffering” in most parts. Whatever the PCB does is what the guts of the part sees …. Given the popularity here on the list of

Re: [time-nuts] LH and long-term oscillator measurement

Hi An alternative: Take the pps out of a ( or maybe several) GPS modules. Divide your oscillator to (about) 1 pps. Feed them into a counter(s) of some sort (TICC or 53xxx or whatever …) Log the data to a file with any serial program you might pick. = At this point you have a data

Re: [time-nuts] Oscilloquartz BVA has been sold. Thank you all who expressed an interest.

Hi Maximize life = put it on the shelf and *never* power it up. It (may) last for a century that way. How you will *know* it’s still doing fine is very unclear. Maximize utility = power it up and keep it on power all the time. If you can plan well, power it up 9 months before you need to use

Re: [time-nuts] Brand new OCXO/TCXO reccomenations

Hi > On Sep 25, 2020, at 5:44 AM, Hal Murray wrote: > > >> 1) In an unconditioned/semi-conditioned space. The ambient temperature can >> slew 20*C easily over the holdover period. (Think sun hitting an outdoor >> enclosure first thing in the morning - the ambient temperature tends to rise

Re: [time-nuts] Oscilloquartz BVA has been sold. Thank you all who expressed an interest.

Hi How often do you loose power? If it’s once a year for < 1 hour …. how big an issue is this to you? Do you *need* to do precision measurements every day? Is restarting a run once a year a major issue? Option one is to simply restart after an outage. Option two is to protect against it. To

Re: [time-nuts] What do people use for measuring temperature?

Hi Roughly speaking 99.9% of all OCXO’s use thermistors as temperature sensors. The normal evaluation process on a new one *probably* would catch something < 0.01C over a few months. You may do it a couple different ways depending on the target OCXO. The net result is still in the “golly

Re: [time-nuts] Phase Noise and ADCs

Hi > On Sep 26, 2020, at 7:22 PM, Magnus Danielson wrote: > > Hi John, > > On 2020-09-26 17:10, John Ackermann N8UR wrote: >> We know that phase noise scales with frequency, so if you multiply >> frequency by 10 you get a 20 dB increase in noise. >> >> What I don't fully understand is how

Re: [time-nuts] What do people use for measuring temperature?

Hi One interesting “oops” using RTD’s: They are close cousins of strain gauges. Some RTD designs are *very* close. Mount them to this or that and they may tell you more about the stress / strain in the mount than about the temperature. You do *not* want to know how many (hundred) temperature

Re: [time-nuts] Phase Noise and ADCs

Hi In addition, the input to the ADC has it’s own noise issues. If you have a really clean clock (or a poor ADC), the noise floor of the input may dominate the noise floor. Bob > On Sep 26, 2020, at 12:28 PM, jimlux wrote: > > On 9/26/20 8:10 AM, John Ackermann N8UR wrote: >> We know that

Re: [time-nuts] What do people use for measuring temperature?

Hi Going back a bit to get closer to the original request ….. Indeed a thermistor is the “high resolution” king of the hill when it comes to temperature measurement. Resistance change of 3% (30,000 ppm) per degree is not uncommon, you can do better … They come in all sorts of packages for not

Re: [time-nuts] Oscilloquartz BVA has been sold. Thank you all who expressed an interest.

Hi Properly charging batteries is a bit complicated. Why does “properly” matter? You want them to be fully charged, but not damage them in the process. That generally involves some sort of variable voltage for the charging source. If you decide to go with Lithium based parts, you can get BMS

Re: [time-nuts] Oscilloquartz BVA has been sold. Thank you all who expressed an interest.

Hi If you run a straight linear regulator setup, then you *do* indeed have a battery voltage that is (nominally) much higher than the “target” voltage. If you run a diode voting input, then the “normal” voltage will be even higher. You can easily get into the 35 to 40V range doing this. Bob

Re: [time-nuts] Help getting 53131A to talk over RS232

Hi The 53131 RS232 thinks it is talking to a printer. You need to enable that on the sub menu *and* then restart ( = power cycle ) the counter. Once it is turned on, you can muck with the serial parameters to get them to line up with your needs. Bob > On Sep 30, 2020, at 5:39 PM,

Re: [time-nuts] Help needed with frequency standard

Hi > On Sep 30, 2020, at 11:45 AM, Luiz Alberto Saba wrote: > > > > Em 29/09/2020 14:08, Bob kb8tq escreveu: >> Hi >> >> You have a lot of stuff that runs off of GPS L1. Any “common mode” issues >> (like ionospheric disturbances) will propagate into a

Re: [time-nuts] Assistance needed to understand some V_OCXO stability concepts.

Hi > …….. > So, I am a little lost in understanding how to characterise this animal, > and how to measure what. I get the feel its performance is actually very > good, but I don't know why, nor how to defend that statement. > > HELP!! > > …... Unfortunately the only accurate way to

Re: [time-nuts] Assistance needed to understand some V_OCXO stability concepts.

gt; Kind Regards > Joe > > > On Thu, Oct 1, 2020 at 5:58 PM Bob kb8tq wrote: > >> Hi >> >>> …….. >>> So, I am a little lost in understanding how to characterise this animal, >>> and how to measure what. I get the fe

Re: [time-nuts] Help needed with frequency standard

Hi > On Sep 29, 2020, at 10:23 PM, Dana Whitlow wrote: > > Mark: > > I don't have a PPS syncable PRS-10 yet, but will probably be getting one > within a > year or so. My expectations are not great, however, because I already know > that > the received GPS time has diurnal wiggles to the tune

Re: [time-nuts] Symmetricom XPRO rubidium

Hi > On Sep 27, 2020, at 10:19 PM, Stewart Cobb wrote: > > I have a Symmetricom* XPRO rubidium which appears to be reaching its end of > life. The very sparse manual says that it sets a "service" flag when the > lamp voltage reaches 600 mV. When I got it, that parameter was at about > 540.

Re: [time-nuts] GPS Distribution amp selection?

Hi Depending on your setup, a very normal passive power splitter could do the job quite well. The 8 port Mini Circuits versions show up on eBay for $20 to $30 (delivered). Bob > On Sep 28, 2020, at 4:25 AM, Kevin Rowett wrote: > > I’m in need of a GPS distribution amp. Looking at choices

Re: [time-nuts] Symmetricom XPRO rubidium

ack to the well? > > David > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob > kb8tq > Sent: 28 September 2020 14:23 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Symmetricom XPRO rub

Re: [time-nuts] What do people use for measuring temperature?

Hi Indeed the most stable (long term) standard is a very high end RTD. These devices have a lot of voodoo in their design. Even with all that, they still arrive with a note on the box that reads “ for applications requiring < 10 mk, re-calibrate before use”. More or less, you *also* need a

Re: [time-nuts] Brand new OCXO/TCXO reccomenations

Hi > On Sep 23, 2020, at 8:20 PM, Forrest Christian (List Account) > wrote: > > I'm hoping some of the list are familiar with the newer currently-available > oscillators available from the distributors. > > Some background: > > I'm starting to play with a short-term 1PPS holdover

Re: [time-nuts] Brand new OCXO/TCXO reccomenations

Hi > On Sep 24, 2020, at 6:32 AM, Hal Murray wrote: > > >> I'm starting to play with a short-term 1PPS holdover application, mainly to >> cover up brief GPS signal loss events (a few minutes at most). > >> I'm probably looking for an OCXO instead of a TCXO, although it looks like >> some

Re: [time-nuts] Oscilloquartz BVA has been sold. Thank you all who expressed an interest.

Hi Two basic types of SLA / VRLA batteries out there: AGM and Gel. For the AGM variety, you want a bit more to your charger. I haven’t worked with Gel cells in a while so they may indeed be easier. Bob > On Sep 25, 2020, at 4:17 PM, Poul-Henning Kamp wrote: > > -------- > Bob

Re: [time-nuts] Alltest used test equipment and parts

Hi I bought a Fluke 732A from them back about 2 months ago. Not exactly cheap and maybe more on topic for Volts Nuts. It came in well packed with no damage. To my limited ability to verify it’s performance, it is in good working order …. (Yes, if I had three of them I could start doing

Re: [time-nuts] Looking for data on a couple of XO's

Hi Both part numbers are “OEM” numbers. In both cases, the official company policy is to not hand out the specs. There are a number of reasons for this, including the time needed to dig out the latest spec. (it’s not as easy to go through 50+ years and > 60,000 paper specs as it might seem …).

Re: [time-nuts] Looking for data on a couple of XO's

ent but like to keep the > smoke in the can. > > Any help is appreciated. > Thanks > Dave > VE7HR > > Sent from my iPad > >> On May 25, 2020, at 5:05 AM, Bob kb8tq wrote: >> >> Hi >> >> Both part numbers are “OEM” numbers. In b

Re: [time-nuts] Looking for data on a couple of XO's

leabay purchase but a gift from a good friend. Here I > thought you might like this. :-) > I shall report back my findings. > Thanks > Dave > > > On Mon, May 25, 2020 at 7:48 AM Bob kb8tq wrote: > >> Hi >> >> It’s a good bet that the power is as indicated. I

Re: [time-nuts] UBlox F9T and Lady Heather

Hi There is indeed a version of LH that *does* work just fine with the F9T and F9P parts. A year ago it was a beta ….. Bob > On May 28, 2020, at 7:12 PM, Ben Hall wrote: > > On 5/28/2020 4:26 PM, Chris Burford wrote: >> I too posted a similar issue with my F9P on the EEVBlog with the exact

Re: [time-nuts] TAPR TICC and TADD-2 Minis

Hi Scope basics: It is not unusual for a scope to have an input channel with a capacitance of 10 to 20 pf. That does not sound like much but …. A 10 MHz square wave has significant energy at 30, 50, 70, 90 MHz (and on up). Unless a coax is terminated at all these frequencies they will be

Re: [time-nuts] TAPR TICC and TADD-2 Minis

anything you look at …. Bob > On Jun 2, 2020, at 1:18 PM, Frank O'Donnell wrote: > > On 6/1/20 9:11 AM, Bob kb8tq wrote: > >> Scope basics: > > > Thanks for the comments. Very helpful as background beyond this immediate > project. > > >> A 10 db pa

Re: [time-nuts] OSA 8600 8607 questtion.

Hi Most OCXO’s similar to the 8600 series use a glass bead thermistor up around 100K ohms. The range of betas available is pretty limited up there. They likely used two in an attempt to reduce the impact of forced cooling to one side vs another. Bob > On Sep 20, 2020, at 8:59 AM, ew via

Re: [time-nuts] IEEE 1588 PTP support on raspberry pi 4 compute module

Hi > On Oct 21, 2020, at 7:28 PM, Wojciech Owczarek > wrote: > > Hi Bob, > > On Wednesday, 21 October 2020, Bob kb8tq wrote: > > >> *Networking* hardware is the issue ….. >> > > Undeniably so, but to what extent? Simply that you can get i

Re: [time-nuts] SMPS or conventional?

Bob > Before I read the previous tread, I was thinking of electronic thermostat/fan > but... > > Em 20/10/2020 10:34, Bob kb8tq escreveu: >> Hi >> >> Not very well organized message here …. I’m still working on my first cup of >> coffee …:) >> >> Fi

Re: [time-nuts] SMPS or conventional?

Hi I must admit, the longevity of the compressor based setup in the typical kitchen fridge continues to amaze me. :). === TEC’s have a fairly limited “pumping range”. It is not uncommon to discover you need to stack them to get this or that job done. We wound up with a stack of 5 to get

Re: [time-nuts] Looking for "The Theory and Design of Quartz Crystal Units" by V.Bottom

Hi > On Oct 23, 2020, at 5:11 PM, Attila Kinali wrote: > > Moin, > > I'm again hunting for some old stuff. Quite a few older papers, > books and technotes (including an article by Bernd Neubig from 1978) > reference V.Bottom's "The Theory and Design of Quartz Crystal Units" > from 1974 This

Re: [time-nuts] Query about insulated coax panel connectors?

Hi Mini-circuits will sell you the transformers already in a box. Needless to say, they do charge a bit for that. Occasionally, you can find them on eBay for a more rational price. If you are going the DIY route, incorporating a couple of common mode chokes on both sides of the transformer is

Re: [time-nuts] Looking for "The Theory and Design of Quartz Crystal Units" by V.Bottom

Hi The gotcha is that if you want to *use* what’s in that book ( I have a copy and went to the course back in the 1970’s) the first step is to grab a chunk of quartz. Next you head over to your X-ray setup and work out what you have. After that you go over to the saw and chop some raw blanks.

Re: [time-nuts] Assistance needed to understand some V_OCXO stability concepts.

it. > > I let it run for 4 days to settle a little, and did a 12 hour run recording > the output from the (analogue) TIC. > Attached is the Adev per TimeLab...will run for a week or so and see what > develops. > > Thanks so far to all the people who have commented and steered my &

Re: [time-nuts] Looking for "The Theory and Design of Quartz Crystal Units" by V.Bottom

Hi > On Oct 25, 2020, at 3:43 AM, Bernd Neubig wrote: > > > > Hi, > >> On Fri, 23 Oct 2020 19:32:16 -0400 >> Bob kb8tq wrote: >> Those authors pretty much only focus on *oscillator* design. ( = >> electronics). >> Bottom is a “crystal guy

Re: [time-nuts] Mentorship needed in learning about Allan Deviation and variation.

hips yet.. A lot of this is simply getting the data into a form that this or that program “likes”. It’s just a lot of tweaking and seeing if the result comes out right. Bob > > Thank You! > Joe > > > On Mon, Oct 26, 2020 at 4:21 PM Bob kb8tq wrote: > >&g

Re: [time-nuts] Rapco 1804M manual and Control Mode Access ?

Hi Normally a date roll over bug is a non-fixable item in these older devices. The basic GPS modules simply did not start to have the “smarts” to handle this until at least a decade after they went out of production. Simple answer is to leave it as is and just use the frequency output. If you

Re: [time-nuts] Mentorship needed in learning about Allan Deviation and variation.

( this is the number of points in the file) > So 141879 seconds is 1day 15hours, but the plot X Axis shows 2 > seconds... > > I cannot find anything wrong with the sample data - no missing samples, etc. > Is this not representing the averaging process? > > Thank You again for

Re: [time-nuts] Mentorship needed in learning about Allan Deviation and variation.

than you probably should be counting on to be useful. Bob > > I cannot find anything wrong with the sample data - no missing samples, etc. > Is this not representing the averaging process? > > Thank You again for your explanations! > Joe > > > On Mon, Oct 26,

Re: [time-nuts] Mentorship needed in learning about Allan Deviation and variation.

Hi I’m pretty sure you can find multiple posts from me spelling it any of a half dozen ways ….. :) Bob > On Oct 27, 2020, at 9:29 PM, jimlux wrote: > > On 10/27/20 6:16 PM, Tom Van Baak wrote: >> Alberto, >> Thanks for asking. The correct spelling is Allan variance or Allan >> deviation,

Re: [time-nuts] 5065A Rb Cavity Rx - SRD repair

Hi As part of your “simple replacement” … keep in mind that it needs to act both as a multiplier *and* as a mixer. The two modes need to be reasonably separate from each other or you (likely) get a real mess. Bob > On Oct 25, 2020, at 4:26 PM, Ulf Kylenfall via time-nuts > wrote: > > >

Re: [time-nuts] Mentorship needed in learning about Allan Deviation and variation.

Hi What are we trying to measure with ADEV? On a frequency source, it’s used to measure the noise of that source. Mostly we put up plots of ADEV to show how quiet our source is. (Yes, we might also measure noise floor or amplifier contributions ….). That’s the statistics part. Now for the

Re: [time-nuts] Mentorship needed in learning about Allan Deviation and variation.

Hi Any practical measure you feed into an ADEV computation will be a look at “device A” versus “device B”. In this case one of them is your GPSDO. What is the other device? ( = your TIC has a DUT input and a REF IN, it compares one to the other ….). If you feed your measurement system with the

Re: [time-nuts] Mentorship needed in learning about Allan Deviation and variation.

even ship toNamibia! > > Having learned a lot from you chaps, for which I am grateful, I think I now > at least know the size of the cliff above of me! > > > Thanks to all.. > regards > Joe > > On Tue, Oct 27, 2020 at 3:29 PM Bob kb8tq wrote: > >>

Re: [time-nuts] Looking for "The Theory and Design of Quartz Crystal Units" by V.Bottom

Hi > On Oct 24, 2020, at 7:43 AM, Attila Kinali wrote: > > On Fri, 23 Oct 2020 19:32:16 -0400 > Bob kb8tq wrote: > >> This book is an introduction to designing AT cut resonators. It came out >> before the SC existed. It’s very much a “starter” book on the subject.

Re: [time-nuts] Looking for "The Theory and Design of Quartz Crystal Units" by V.Bottom

Hi >From what I can see, all are essentially editions of the same book, updated as he continued to do his classes. Bob > On Oct 23, 2020, at 9:50 PM, Wes wrote: > > Attila, > > Amazon says (Out of print): > > * Publisher : McMurray Press; 1st Edition (January 1, 1968) > * Language: :

Re: [time-nuts] Frequency Counter Choice

Hi …. and now I have a copy :) Bob > On Oct 22, 2020, at 6:12 PM, Attila Kinali wrote: > > On Thu, 22 Oct 2020 13:29:07 -0400 > Bob kb8tq wrote: > >> There is a paper running around behind the IEEE paywall by Collins that >> details >> one approach

Re: [time-nuts] IFCS 2020 tutorial - low noise electronics for time/frequency metrology

Hi The gotcha is that all X7R tells you is that the temperature dependence of the part falls inside a certain set of limits. Back many decades ago there were very few formulas out there to make this or that spec part. Pretty much everybody made a part type with the same material. Since the

Re: [time-nuts] WWVB PM Time Questions

Hi Or … you can cheat. If the objective is a lab reference of some sort (and not a stand alone clock), cheating may be an acceptable solution. Add a real time clock into the mix and you know the month / day / hour / minute before you ever see the first cycle from the antenna. Indeed, you

Re: [time-nuts] time-nuts Digest, Vol 193, Issue 1

Fri, 31 Jul 2020 21:00:13 + >> From: "Poul-Henning Kamp" >> To: Discussion of precise time and frequency measurement >>, Bob kb8tq >> Subject: Re: [time-nuts] WWVB PM Time Questions >> Message-ID: <85171.1596229...@critter.freebsd.dk> &

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

Hi > On Aug 3, 2020, at 6:32 PM, Poul-Henning Kamp wrote: > > > Attila Kinali writes: > >>> The main reason I dont just repair/replace the A15 is that >>> I want to find out how much instability the PSU contributes. >> >> There are very few points where supply voltage (in)stability

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

Hi > On Aug 4, 2020, at 3:50 PM, Poul-Henning Kamp wrote: > > -------- > Bob kb8tq writes: > >>> I have not given much thought to A11 yet, and I do find a certain >>> elegance in the wien-bridge approach. It is worth noting that the >>> actual hea

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

Hi > On Aug 4, 2020, at 5:23 PM, Poul-Henning Kamp wrote: > > -------- > Bob kb8tq writes: > >>> The "modern" approach to that is to modulate or dither with a >>> good long PRNG to whiten the noise, and while good in theory, >>> it is not _t

Re: [time-nuts] eLORAN will be on the air GRI 99600

en 3 and 5 “bands” depending on how you count them. Various chunks of spectrum between 1 and 2 GHz get used by this or that system. Bob > > But, a good quality terrestrial option would be useful too. > > On Thu, Aug 6, 2020 at 3:40 PM Bob kb8tq wrote: > >> Hi >> &g

Re: [time-nuts] eLORAN will be on the air GRI 99600

Hi The problem with CDMA timing is that not all network operators sync their systems to GPS in all areas. That results in some really strange timing issue when using one of the CDMA based devices. More or less, Symmetericom got a *lot* of devices into the field before they found that out …..

Re: [time-nuts] eLORAN will be on the air GRI 99600

Hi > On Aug 6, 2020, at 4:40 PM, jimlux wrote: > > On 8/6/20 9:17 AM, Taka Kamiya via time-nuts wrote: >> Someone in this thread mentioned "at least 2 satellite time and frequency >> solutions" exists already. I only know of GPS (GNSS) constellations. >> What's the other? > > Transit? > >

Re: [time-nuts] eLORAN will be on the air GRI 99600

Hi The Russians put up the Gloanss system many years ago. It took a while to get all the kinks out of it. It has been running pretty well for over a decade: https://en.wikipedia.org/wiki/GLONASS The European Union is in the process of fleshing out the

Re: [time-nuts] Looking for information on Brightline oscillator

Hi In that era, 12 and 24V are the two candidate supply voltages. Assuming there are no wires to the other pins, no need to supply power to them. What to do: Try 12V and see what happens. If you get a stable output at > +7 dbm and good ( = low ) harmonics. That’s the supply. If not, slowly

Re: [time-nuts] eLORAN will be on the air GRI 99600

Hi > On Aug 6, 2020, at 9:38 PM, Forrest Christian (List Account) > wrote: > > I probably need to clarify where I'm coming from in relation to my previous > message. > > I have a fair bit of background in dealing with using GPS clock sources for > synchronization at communication sites.

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

Hi The idea is that over a limited coverage area, you can supply “correction” info to reduce the impact of propagation. GPS (and other GNSS systems) do this sort of thing already. Just as with GNSS, the corrections will (likely) only get you just so far. Bob > On Aug 7, 2020, at 11:32 AM,

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

) Taka Kamiya > KB4EMF / ex JF2DKG > > > On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq > wrote: > > Hi > > > >> On Aug 9, 2020, at 7:03 PM, Tom Van Baak wrote: >> >> Hi Stu, >> >> There's no problem with a semi-co

Re: [time-nuts] WWVB SDR discussion

Hi The problem with the crystal is that it has a temperature coefficient. As a narrow band filter, it will have a *lot* of delay. Crystal resonance moves (with temperature) and the delay changes. How much delay depends a lot on a bunch of fiddly details. A 10 to 100 Hz wide bandpass could

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

ed by just listening into what's > > already transmitted (like GPS) and do some math on our side. > > > > On more broader sense, was GPS originally designed to provide timing > > service? Or is it a byproduct of needing to measure location and speed, > > thus

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

Hi If a more extensive rebuild is in the works ….. +/-20V is (as has been observed) not an ideal voltage for “modern” electronics. If you dig into each of the boards, there is a lot of “drop it down right now” regulation done on a board by board basis. More or less what might be there: A1

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

Hi > On Aug 4, 2020, at 2:49 PM, Poul-Henning Kamp wrote: > > -------- > Bob kb8tq writes: > >>>> I would go for the LTZ1000 if you can. The LM399 has gone out of >>>> fashion for a reason: [...] >>> >>> Yes, I know, being also

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

Hi > On Aug 4, 2020, at 3:07 PM, Poul-Henning Kamp wrote: > > -------- > Bob kb8tq writes: > >> If a more extensive rebuild is in the works ….. > > Yes, that's where we're headed eventually, but I prefer to do it > incrementally. > >> +/-20V is (as

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