Re: [time-nuts] Power supply for time source concerns

Hi > On Dec 24, 2019, at 6:40 AM, Poul-Henning Kamp wrote: > > > >> That again depends on topology and control type. The canned converters >> are almost always optimized to have the lowest number of switches and >> work with cheap magnetics (single coil) without easily entering

Re: [time-nuts] Using HP5071A with dead tube along with GPS

Hi Since the devices may sit for a *long* time on the shelf, humidity can soak into parts. Adsorption / desorption rates normally are very different so a brief soak in may mean a *long* soak out. Bob > On Dec 23, 2019, at 4:01 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> Like all

Re: [time-nuts] 10MHz, distribution amplifier.

Hi Well, given the 10:1 price difference, I’d say it’s safe to guess the 58502A is a bit better piece of gear. The BG7TL is quite adequate for normal 10 MHz distribution around the lab / shack. None of these gizmos (including the 58502) are “good enough” if you plan on direct multiplication

Re: [time-nuts] 10811 performance

Hi To that I would add - how long was it on power when measured? Does it run on power 24/7 at the club or is it power down 99% of the time? 10811’s (at least as much as other OCXO’s) “like” to be power on all the time. However using it one way and calibrating it another way may not be the best

Re: [time-nuts] 10811 performance

cility with almost 40 > major buildings. Nothing we can do in our three little ex FEMA trailers > could show up on the electric meter, even if we tried. > > The fun part will be at home, where I try to test the different standards, > using the test equipment I have. > > Robert

Re: [time-nuts] 10811 performance

Hi The simple answer is that a ~ $100 Chinese GPSDO and a ~ $20 MiniCircuits power splitter (all off of eBay) should be able to drive a couple of counters and a few other pieces of gear. If they are all “power on” when the bench is in use, daisy chain from the “important” stuff to the less

Re: [time-nuts] u-Blox ZED-F9T block diagram or timing knowledge available here?

Hi If you go back in the list archives, there is a lot of info on doing this and that with the F9P and the F9T. For a while, there was speculation that the price on them would come down quite a bit. So far that does not seem to be happening. Bottom line is that both the F9P and F9T have

Re: [time-nuts] u-Blox ZED-F9T block diagram or timing knowledge available here?

Hi For a rubidium, the sawtooth error may or may not be as big a deal as for an OCXO. With an OCXO your loop time constant is likely below an hour. Indeed it may be a couple of minutes. Bridges do pass through that sort of loop and mess up the output. The math: 10 ns hanging bridge at 1

Re: [time-nuts] u-Blox ZED-F9T block diagram or timing

gest so I just got inundated with > responses. > > I've cut down the the comments of interest and reply in-line below to > hopefully cut down on the reading. Apologies if this is a mess. > > -Tim > > On Tue, Jan 7, 2020 at 9:00 AM wrote: > >> >> From: Bob k

Re: [time-nuts] Synchronisation of crystal oscillators

Hi To “see” the zero beat, they have to be hooked to some sort of test gear. It’s only going to have just so much isolation. The fine old 3048 phase noise test set was pretty good at injection locking the devices you were testing …. Loaded Q on a “typical” 10 MHz OCXO is likely in the 500K

Re: [time-nuts] HP 5335A and using the HPIB for control

Hi I’ve used the 5335 in exactly this mode for a lot of years. > On Mar 6, 2020, at 7:28 PM, Frank Stellmach > wrote: > > Hello Perrier, > > I'm also a bit confused, what your requirements, and what your capabilities > are. > > The HP5335A definitely can handle gate times up to 10^7

Re: [time-nuts] New Subscriber, DIY GPSDO project (yes, another one)

Hi As far as I know there is no “closed form” solution to tuning a GPSDO. It is very much a measure / tweak / measure / tweak sort of thing. That said, there are a lot of basic design constraints that are pretty well known. Your DAC needs to have a pretty small LSB. Updates are normally done

Re: [time-nuts] New Subscriber, DIY GPSDO project (yes, another one)

ote: > > H > > On 2020-03-08 07:38, Poul-Henning Kamp wrote: >> >> In message <5583e434-4c72-4a4f-a60b-75a4204ef...@n1k.org>, Bob kb8tq writes: >> >>> Backing up a bit …. the objective is not to minimize overshoot or >>> keep the loop

Re: [time-nuts] New Subscriber, DIY GPSDO project (yes, another one)

Hi One of the biggest issues in all this is that while a group of OCXO’s may have some similar characteristics, they most certainly will not all have the *same* characteristics. This one is at 5x10^-13 at 1 second and the next one out of the box is at 5x10^-12 at 1 second. On top of that, your

Re: [time-nuts] Modern Rb atomic reference vs classic Cs

Hi Backing off a bit, as long as GPS is doing it’s part ( or your GNSS system of choice …) an OCXO based setup may do as well as / better than your typical “almost dead” used Cs standard. It is very easy to find a used Cs with a dead tube. It is quite hard to find one with a tube that is

Re: [time-nuts] time-nuts Digest, Vol 188, Issue 22 Re. Pi

Hi Even things like 1N4001’s can be used as varicap diodes …. Bob > On Mar 14, 2020, at 4:08 AM, Andre wrote: > > Hi, what about using an SDR to micro adjust the 19.2 MHz crystal? > > I found that replacing the input capacitor (normally 18-27pF) with a reversed > blue SMD LED seems to help.

Re: [time-nuts] GPS module recommendation for Pi timing

Hi > On Mar 14, 2020, at 10:54 AM, Brian Lloyd wrote: > > On Fri, Mar 13, 2020 at 8:49 PM Bob kb8tq wrote: > >> Hi >> >> If you always operate in fixed locations, your chances of seeing a slip >> are not that high. The original post question and reference

Re: [time-nuts] GPS module recommendation for Pi timing

Hi > On Mar 14, 2020, at 1:36 PM, Brian Lloyd wrote: > > On Sat, Mar 14, 2020 at 10:57 AM Bob kb8tq wrote: > >> Hi >> >> >>> On Mar 14, 2020, at 10:54 AM, Brian Lloyd wrote: >>> >>> On Fri, Mar 13, 2020 at 8:49 PM Bob kb8tq wrot

Re: [time-nuts] Modern Rb atomic reference vs classic Cs

and be happy. I actually run a GPSD-TCXO as a instant > on sort of right there for my ham stuff. Power consumption sub 10 Watts. > Then flip to a HP3801 or any number of alternates including Cesium for > serious stuff like D-PSK-R development. > Signed one lazy ham. > Regards &g

Re: [time-nuts] GPS module recommendation for Pi timing

Hi > On Mar 14, 2020, at 4:10 PM, Brian Lloyd wrote: > > On Sat, Mar 14, 2020 at 12:52 PM Bob kb8tq wrote: > >>> I understand completely. Still, I have to come up with a >> reasonably-priced >>> source of time and it does seem like GPS is the right answer.

Re: [time-nuts] Ultra Stable Rb

Hi A few of the long running FRK’s ( in a very similar package … hmmm ….. wonder why …. yes, I was there way back then and know very well why :) ) have crazy good long term aging. That said, I don’t think that I’ve seen a FRK quite this good. Thanks for sharing !!! Bob > On Apr 8, 2020, at

Re: [time-nuts] Ultra Stable Rb

> On Apr 8, 2020, at 2:32 PM, djl wrote: > > What a tease! OK, very well WHY??? > Don > > On 2020-04-08 08:04, Bob kb8tq wrote: >> Hi >> A few of the long running FRK’s ( in a very similar package … >> hmmm ….. wonder why …. yes, I was there way back then

Re: [time-nuts] The 10811 double oven mystery

Hi Well, based on conversations with the people who designed the part, the outer oven’s only function was to take care of a potential cold end problem. At the time, the telecom guys were thinking of putting GPSDO’s in systems with no heating on the enclosures. That idea died when they ran into

Re: [time-nuts] Ultra Stable Rb

it? > > My granddad worked for a guy in LA called Madman Muntz who made tv's that way > in the late 1940's. They worked. Sorta. For a while. If the signal was strong > enough. > Voila! $X-$400 > > On 2020-04-08 13:51, Bob kb8tq wrote: >> Hi >> At the time EG

Re: [time-nuts] Phase noise confusion II

e > construed as 6 X the rms value. > > Dana > > > On Fri, Apr 10, 2020 at 6:57 AM Bob kb8tq wrote: > >> Hi >> >> Which of the multitude of definitions are we talking about? >> >> One very common definition looks at peak to peak

Re: [time-nuts] Phase noise confusion II

Hi Which of the multitude of definitions are we talking about? One very common definition looks at peak to peak jitter and does not care about the center. Another looks at +/- peak to edge and then uses the greater of the two numbers. Other definitions look at RMS jitter and generally don’t

Re: [time-nuts] Ultra Stable Rb

y to make a > stable Rb versus one > that drifts a lot? Never mind price issues. > > Could one buy, say, a PRS-10, extract the physics package from it, then > engineer a stable > Rb with that as a core? > > Dana > > > On Wed, Apr 8, 2020 at 4:19 PM Bob kb8tq wrote

Re: [time-nuts] Connector options for HP10811A?

Hi The connector is a very normal 2 x 15 position 0.156” spaced edge connector. You can buy them on Amazon: https://www.amazon.com/gp/product/B0721L5VSD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8=1 From

Re: [time-nuts] Phase noise confusion II

to solving the “problem”. Bob > On Apr 10, 2020, at 12:27 PM, Richard (Rick) Karlquist > wrote: > > > > On 4/10/2020 5:47 AM, Bob kb8tq wrote: >> Hi >> It is not at all uncommon to …. errr …. make that decision, regardless >> of what the customer might thin

Re: [time-nuts] The 10811 double oven mystery

Hi Running a hard disk at -40 C is pretty much a no-go sort of thing. Even finding CPU or FPGA chips rated for operation down there is difficult / expensive. DRAM chips with the “right” timing … not so much. Bottom line - the heater / HVAC costs *way* less than designing all that stuff to

Re: [time-nuts] Connector options for HP10811A?

not install all of the pins? If they do install all of them > why do they show some missing, when they show them installed on the other two > products? I would like to use the through hole pins socket. > > Robert, KA3ZYX > > On 04/08/2020 10:06 PM, Bob kb8tq wrote: >> H

Re: [time-nuts] OCXO and fluctuations after EFC adjustment

d to be done, but these days the usual (and > often only) criterion other than part value (e.g. 15V 200uF +/- 10%) seems to > be cost (cheapest == best). > > Sad isn't it. > > David > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Beh

Re: [time-nuts] Chinese GPSDOs

Hi GPSDO’s come from China for a very simple reason: All the world’s scrap gear is sent to China for “reclamation”. It’s just another element in the great flow of material being recycled. For a variety of reasons China is the destination of choice for electronics scrap. Like it or not,

Re: [time-nuts] LightSquared is back now called Ligado

Hi Was that +9.8 or -98 dbm ? :) At -98 they probably *could* coexist with GPS. Not real clear how well there system would work at that level though. Bob > On Apr 17, 2020, at 1:37 PM, Scott McGrath wrote: > > Supposedly lowering Tx power on terrestrial network from +23 DBm to +9.8 DBm >

Re: [time-nuts] PRS-10 PPS output

r customer gets 5ps using a better reference. I > wanted to explore the precision of the IRIG time stamp system, and am > trying to upgrade my lab as inexpensively as possible to find the limits. > > Anyway, everyone's feedback is appreciated. > > --mike > > On Tue, Apr 7, 202

Re: [time-nuts] PRS-10 PPS output

d free > running 10MHz reference. > With the shown setup I can store the arrival time/ rising edge zero > crossing of all of the inputs to a file for analysis. > > Any further suggestions on test setup? > > --mike > > > > > [image: pps_fail.png] >

Re: [time-nuts] Phase noise principle and measuring confusion

Hi Phase is what drives an ADEV measurement ( frequency from phase ….). Phase noise the noise at a specific offset from a carrier, often normalized to a 1 Hz bandwidth. Phase noise is a different measure than “phase”. ( = they are not the same thing ). Indeed a single mixer can be used as the

Re: [time-nuts] Phase measurement of my GPSDO

s of a fancy piece of gear. Bob > > > Tobias > > > > On Mon., 13 Apr. 2020, 23:53 Bob kb8tq, wrote: > >> Hi >> >>> On Apr 13, 2020, at 5:06 PM, Tobias Pluess wrote: >>> >>> Hi Bob >>> awesome, thanks! of cour

Re: [time-nuts] Phase measurement of my GPSDO

not just one HP5335? Your test > setup has two output. One goes to start, the other goes to stop. Measure > the time interval. Isn't that the goal? > > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > > On Monday, April 13

Re: [time-nuts] Phase measurement of my GPSDO

> Can you give some hints on that? > > Best > Tobias > HB9FSX > > > > > On Fri, Apr 3, 2020 at 1:45 PM Bob kb8tq wrote: >> >>> Hi >>> >>> The quick way to do this is with a single mixer. Take something like an >>> o

Re: [time-nuts] Phase measurement of my GPSDO

I want to see how it actually > works. ;-) Be careful any time you code this stuff for the first time. It’s amazingly easy ( = I’ve done it ….) to make minor errors. That’s in no way to suggest that you should not code it up yourself. I generally do it in Excel or in C. Bob > > >

Re: [time-nuts] Phase measurement of my GPSDO

, MDEV and TDEV calculations in Matlab by > myself. I use TimeLab to see what numbers I should expect, and then I want > to compute it all myself in Matlab because I want to see how it actually > works. ;-) > > > Best > Tobias > > > > On Mon, Apr 13, 202

Re: [time-nuts] OCXO and fluctuations after EFC adjustment

Hi Spurs on an ADEV plot look like ripples in the curve. If you have a part with good close in phase noise / good short tau ADEV, you probably can see effects from spurs that 120 db down in the vicinity of 10 Hz. Bob > On Apr 11, 2020, at 4:22 PM, Hal Murray wrote: > > >

Re: [time-nuts] OCXO and fluctuations after EFC adjustment

Hi Would you *really* want to read a book about how from August of 1986 to January of 1993 AVX NPO’s had some sort of issue ( not that the issue is clearly known, just that they are flakey) and that by 1994 the parts with values below 220 pf in 0805 seemed to be fixed? Again, the task was

Re: [time-nuts] OCXO and fluctuations after EFC adjustment

Hi > On Apr 11, 2020, at 8:10 PM, Richard (Rick) Karlquist > wrote: > > > > On 4/11/2020 2:25 PM, Bob kb8tq wrote: >> Hi >> Would you *really* want to read a book about how from August of 1986 to >> January of 1993 AVX NPO’s had some sort of issue ( no

Re: [time-nuts] OCXO and fluctuations after EFC adjustment

Hi Well….. Once upon a time, there was a design review on a space part. There was an tantalum cap used in a couple of places in the design. It was a 50V part and running at 12V. We got dinged for it. Turns out if you over derate electrolytics (of any sort) there is a failure mechanism that

Re: [time-nuts] Phase measurement of my GPSDO

ldn't be a problem, right? > > But I agree, if you cannot correct for the spillovers it becomes even more > difficult. > > > Tobias > > On Tue., 14 Apr. 2020, 01:38 Bob kb8tq, wrote: > >> Hi >> >> The gotcha with using a conventional counter (as

Re: [time-nuts] Phase measurement of my GPSDO

stop. >> Measure the time interval. Isn't that the goal? >> >> ----------- >> (Mr.) Taka Kamiya >> KB4EMF / ex JF2DKG >> >> >>On Monday, April 13, 2020, 5:53:52 PM EDT, Bob kb8tq >> wrote: >> >>

Re: [time-nuts] OCXO and fluctuations after EFC adjustment (Ben Bradley)

Hi Electrolytic caps have a lot of leakage. That’s the bad news. The good news is that if you maintain a stable voltage on a tantalum part, the leakage decays ( = drops off) with time. In a system with a fixed EFC, you probably can get away with a tantalum part. You will have to wait a bit for

Re: [time-nuts] Phase measurement of my GPSDO

sign on my bucket list since quite a while. I planned to > make my own time-tag counter with two TDC7200 as interpolators, to get ps > resolution, very similar to the TAPR TICC. > > > Tobias > > > On Tue, Apr 14, 2020 at 1:48 PM Bob kb8tq wrote: > >> Hi

Re: [time-nuts] Using speaker / earphone for PPS testing (not a question)

Hi One of the simplest justifications I can think of for a dirt cheap “Chinese” digital ’scope is to capture short burst stuff like narrow pps pulses. 10 us / non-adjustable is a *very* common spec for a 1 PPS. Bob > On Apr 21, 2020, at 4:56 AM, Chris Burford wrote: > > I reached out to

Re: [time-nuts] The 10811 double oven mystery

was hard to get to. I realize that in practice this is likely > to be difficult (: > > Mark Spencer > > m...@alignedsolutions.com > 604 762 4099 > >> On Apr 8, 2020, at 7:09 PM, Bob kb8tq wrote: >> >> Hi >> >> Running a hard disk at -40 C i

Re: [time-nuts] Quartz crystal aging -- unlocked Z3801A

Hi Welcome > On Apr 6, 2020, at 7:29 PM, Louis Taber wrote: > > Hi All, My first note to the mailing list. > > I never thought I would be able to do see a quartz crystal age. All > earlier attempts were buried in the noise & temperature effects. This data > set results in a very

Re: [time-nuts] GPS module recommendation for Pi timing

Hi Pretty much any generic GPS module will get you to 1 ms without a lot of effort. There is certainly no need for the M9F or M9T sort of parts. A typical module will deliver a pps signal that is better than 100 ns as far as timing. How good you can do via serial on a Pi depends a bit on how

Re: [time-nuts] GPS module recommendation for Pi timing

;> https://crin.eng.uts.edu.au/~darryl/Publications/Pi-hat_current.pdf > > > Thank you. Perfect. Reading now. > > Bob KB8TQ: We are laying out our own board as it will be doing other things > besides GPS time/frequency keeping. Trying to avoid the use of USB. 1pps > will go directly to

Re: [time-nuts] GPS module recommendation for Pi timing

Hi One of the ways a GPS module “freaks out” is to slip by one code cycle (which is just slightly over 1 ms). If you have a surveyed location, some firmware will reject the solution and at least you will be in holdover. In a case where the *only* thing you can trust is the GPS, filtering isn’t

Re: [time-nuts] GPS module recommendation for Pi timing

generations of Raspberry Pi as well >> as the stability profile of the uBlox M8Q: >> >> https://crin.eng.uts.edu.au/~darryl/Publications/Pi-hat_current.pdf > > > Thank you. Perfect. Reading now. > > Bob KB8TQ: We are laying out our own board as it will be doing other

Re: [time-nuts] GPS module recommendation for Pi timing

Hi If you always operate in fixed locations, your chances of seeing a slip are not that high. The original post question and reference here were to timing in a *mobile* situation. Bob > On Mar 13, 2020, at 4:14 PM, Hal Murray wrote: > > > Thanks. > > kb...@n1k.org said: >> One of the ways a

Re: [time-nuts] Buffer amplifier, OP Amp, vs MMIC, vs discrete?

Hi The file you reference is showing a rather complex single mixer setup. It simply omits the mixer from the schematic. The audio amplifier that is part of that setup is going to improve the measurement floor by a couple of db. With most people saying that it’s way to complex to set up to

Re: [time-nuts] PRS-10 PPS output

, Vol 189, Issue 7 > - >> >> Message: 1 >> Date: Fri, 3 Apr 2020 15:48:50 -0400 >> From: Bob kb8tq >> To: Discussion of precise time and frequency measurement >> >> Subject: Re: [time-nuts] PRS-10 PPS output >> >> Hi >> >> At least acc

Re: [time-nuts] Noise Floor

Hi The amplifier board was sitting in mid air with no shielding. Stray pickup from who knows where *is* a possibility. Bob > On Mar 25, 2020, at 6:32 PM, John Miles wrote: > >> -Original Message- >> From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of >>

Re: [time-nuts] Crystal filters in test equipment

Hi Narrowband filters have significant amounts of delay. Any change in that delay (like from temperature or ……) will phase modulate the oscillator. Conventional wisdom these days is that your ADEV will be better without the filter. Phase noise wise, you can only get just so close to the …

Re: [time-nuts] Phase measurement of my GPSDO

Hi What you have measured *is* the noise floor of a 5335 when trying to use it to measure ADEV. Anything past the numbers on your plot will be “past” what the 5335 can “see”. Indeed, even when you get close to those numbers, things may get a bit weird due to the fact that you are measuring

Re: [time-nuts] Phase measurement of my GPSDO

Hi The quick way to do this is with a single mixer. Take something like an old 10811 and use the coarse tune to set it high in frequency by 5 to 10 Hz. Then feed it into an RPD-1 mixer and pull out the 5 to 10 Hz audio tone. That tone is the *difference* between the 10811 and your device under

Re: [time-nuts] Phase measurement of my GPSDO

> > > Tobias > > On Fri, Apr 3, 2020 at 1:45 PM Bob kb8tq wrote: > >> Hi >> >> The quick way to do this is with a single mixer. Take something like an old >> 10811 and use the coarse tune to set it high in frequency by 5 to 10 Hz. >&

Re: [time-nuts] Phase measurement of my GPSDO

Dana > > > On Fri, Apr 3, 2020 at 6:45 AM Bob kb8tq wrote: > >> Hi >> >> The quick way to do this is with a single mixer. Take something like an old >> 10811 and use the coarse tune to set it high in frequency by 5 to 10 Hz. >> >> Then feed

Re: [time-nuts] Phase measurement of my GPSDO

eBay > GPSDO, and as we all know, these are sometimes of doubtful pedigree. > But still, below the 10s tau, the ADEV and MDEV are so close to the noise > floor that I would say this measurement is useless. > > But it still does not explain why my 5335A is so bad. > > > Tobias > HB9

Re: [time-nuts] Phase measurement of my GPSDO

ially the same as comparing two 1PPS signals, isn't it? >>> Ok there is a minor difference: since the 1PPS signals are divided down >>> from 10MHz, their noise is also divided down, which is not the case for >> the >>> DMTD. >>> However, in t

Re: [time-nuts] Buffer amplifier, OP Amp, vs MMIC, vs discrete?

Hi With many (but not all) of the MMIC’s the phase noise / ADEV degrades more than a bit as you drive them near their “rated” output. Since you don’t *need* a lot of gain in a distribution amp, their high(er) gain is of no benefit. If you pad them on the input, noise figure degrades. If you

Re: [time-nuts] Phase measurement of my GPSDO

gt;> >>> Tobias >>> >>> >>> On Fri, Apr 3, 2020 at 3:30 PM Dana Whitlow >> wrote: >>> >>>> Caution: opamps make terrible limiters- their overload behavior is >>>> generally ugly >>>> and unpredictable. It's m

Re: [time-nuts] Phase measurement of my GPSDO

ed to > compare *two* clock signals, so a single mixer won't be of much use, would > it? > > Tobias > > On Sat., 4 Apr. 2020, 01:51 Bob kb8tq, wrote: > >> Hi >> >> A *single mixer* setup is something that can be done quickly and easily. >> The *dua

Re: [time-nuts] Power glitch - Sat morning

Hi One minor point: If you *do* decide to digitize the line, think about how much headroom you want on the digitizer. That applies both in the amplitude and time domains. On a 120V 60 Hz line, is an 800V 300 us pulse of interest? How about a half cycle at 2X or (1/4) line voltage? If you

Re: [time-nuts] Power glitch - Sat morning

Hi I agree that it shouldn’t be something that happens. That’s why half the house going dark was a bit weird ….. Bob > On Mar 31, 2020, at 10:53 AM, Chris Caudle wrote: > > On Tue, March 31, 2020 8:28 am, Bob kb8tq wrote: >> If you have a two phase circuit, are both pha

Re: [time-nuts] Power glitch - Sat morning

Hi At some point the rational question would be - how does this relate to timing? Getting a sound card so that it will do a reasonable job of time tagging edges can be “fun”. My approach was always to feed a “known” signal into that second channel ….. Bob > On Mar 31, 2020, at 8:46 PM, Hal

Re: [time-nuts] New Thunderbolt monitor

Hi The gotcha with 3D printing is that it’s not cheap. That plastic whatzit that you buy in the store at 10 for a dollar likely will cost you $10 to print. In addition, the part from the store (done in a proper mold) looks and works a lot better. That said, it’s *way* cheaper than CNC

Re: [time-nuts] Hetrodyning concept

Hi If you feed two identical signals into a double balanced mixer, you get 2X the input frequency and a DC component as the “ideal” outputs. You also have the input feed through and N x the input bouncing around as “non-ideal” signals. ( = the full expansion has a *lot* of terms in it). A

Re: [time-nuts] Vaperware Parts and pulse stretching circuits

Hi For around $10, you likely can get a stencil with your board order. Screening solder on the board can be set up with masking tape and a few scrap boards as “stops”. With the solder paste already in the correct locations, there is a lot less need for messing around. The board can be reflowed

Re: [time-nuts] On choosing reasonable synthesizer PN requirements

Hi The “wiggles” he is chasing are about 2-3 Hz (by eyeball on his charts). At 2.4 GHz, that is a fairly convenient ~1 ppb. The Z-3801 (if it was in good health) should be easily able to hold that level of performance. It’s not clear which MD-011 he is using, but it is a pretty good bet it

Re: [time-nuts] On choosing reasonable synthesizer PN requirements

Hi Assuming you know the power level you will be delivering to the sat and the noise figure of the receiver on the sat, the calculation is just as presented earlier. If the antenna on the sat has gain, that also gets into this and that. Using some made up numbers, since I do not have the

Re: [time-nuts] GPSDO advice

Hi > On Apr 24, 2020, at 12:56 PM, Wes wrote: > > No, I'm not looking for advice on how to build one but what I might buy. My > need is strictly hobbyist (ham radio). I currently have a Bodnar dual > frequency unit, that gives me frequency and a TAPR, (Synergy Systems) that > gives me 1

Re: [time-nuts] Vaperware Parts and pulse stretching circuits

Hi Metcal’s are great soldering setups. They also are *expensive* soldering setups. I mumble and grumble each time I do a re-stock on tips. I know of several plants that tooled up on Metcal’s and then switched to something else after a few years. The issue was never performance. It always

Re: [time-nuts] GPSDO advice

ly is “worse” for frequency. ( yes, some are pretty bad at both …). A SRS 740 with the Rb option is one of the alternatives….. Pricing for all the options is on their web site. Bob > > > On 4/24/2020 10:14 AM, Bob kb8tq wrote: >> Hi >> >>> On Apr 24, 2020, at 12:5

Re: [time-nuts] time-nuts Digest, Vol 189, Issue 37

Hi Based on a 30 db carrier to noise floor at the sat: Going from -120 dbc/Hz to -60 dbc/Hz will have << 0.1 db impact. Going from -60 dbc / Hz to -30 dbc/Hz would be in the 3 db range. Simply put, the signal is way down in the noise by the time it gets to the sat. There is very little gain

Re: [time-nuts] NTP server using an OCXO, GPS chip and Raspberry Pi

Hi Assuming you can get a good sky view for the GPS / GNSS device, that’s about all you need. Feed it into whatever computer you decide to use and move on. The OCXO is simply a power hungry “non contributor” in this case. Bob > On Apr 24, 2020, at 2:46 PM, Andreas Kempe wrote: > > Hello

Re: [time-nuts] Vaperware Parts and pulse stretching circuits

Hi One gotcha with Metcal’s is when using a variety of solders. This may not apply in a home environment. It certainly does in industry. Different alloys have different melting temperatures. To match up with them, you change the tip on a Metcal. There are other systems that do this with the

Re: [time-nuts] What to do with your dead cesium

Hi If people are scrapping out 5065’s there just *might* be a few of us interested in the various boards and modules that now are surplus to the “new” use. Contact me off list. I’ll gladly pay shipping. Bob > On Apr 21, 2020, at 3:48 PM, ed breya wrote: > > I did a similar thing with an

Re: [time-nuts] Using speaker / earphone for PPS testing (not a question)

ources. That was for PPS. (you know I'm behind a rack stepping over > wires and trying to see if pps is actually coming out?) > > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > >On Wednesday, April 22, 2020, 2:16:17 PM EDT

Re: [time-nuts] What to do with your dead cesium

Hi I figured it wouldn’t hurt to ask. Who knows, maybe all this talk has somebody else sending the innards of one off to oblivion. Bob > On Apr 21, 2020, at 5:02 PM, ed breya wrote: > > Sorry Bob, but in my case, it was long ago, and the few unnecessary 5065A > boards are long gone. The

Re: [time-nuts] Using speaker / earphone for PPS testing (not a question)

Hi A lot also depends on what sort of voltage / power the speaker is expecting. If it’s a high impedance voice coil gizmo things aren’t going to be as easy as with a piezo gizmo designed to work in a 1.3V battery powered greeting card. Where did I leave that 10KV output amplifier ….. should be

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

Hi Very cool !!! Sort of sounds like we will not be doing this in a basement lab any time soon :( Bob > On Apr 23, 2020, at 11:27 AM, Anders Wallin > wrote: > > Today (a mere 4-and-a-half months since my post below) we managed to lock > the ultra-stable laser to 3 pairs of Zeeman-components

Re: [time-nuts] GPS antenna splitter recommendation?

Hi The original splitters mentioned most certainly do *NOT* short the DC to ground. I have used those splitters for decades to power GPS gear. We have used them in production for runs of thousands of parts …. Before anybody goes off and spends $1,000 on a splitter, think very hard about what

Re: [time-nuts] GPS antenna splitter recommendation?

As a result I'm reading this > thread with interest since it seems that a lot of the answers would be > suitable for what I'm hoping to do as well. > > > On Thu, Apr 30, 2020 at 2:51 PM Bob kb8tq wrote: > >> Hi >> >> The original splitters mentioned most certainly

Re: [time-nuts] TICC / TimeLab fun

Hi You have three inputs to the TICC: 1) The “frequency standard” input that delivers 10 MHz to the device. 2) The (likely pps) to channel A 3) the (likely also pps) to channel B The device runs a continuous time count based on the frequency standard input. Each edge it sees on channel A

Re: [time-nuts] GPS antenna splitter recommendation?

30/2020 7:33 AM, Bob kb8tq wrote: >> Pretty much all the Mini Circuits splitters will pass DC. > > Hi Bob and all, > > That's absolutely correct. Something you might consider is what I did - I > got a pair of Mini-Circuits ZC6PD-1900W's cheap on the e-place. > Frequenc

Re: [time-nuts] GPS antenna splitter recommendation?

Hi Pretty much all the Mini Circuits splitters will pass DC. The only ones that don’t are the ones that show “goes to DC” on the data sheet. Those are resistive splitters. I’ve run thousands of GPS modules through a lot of different Mini Circuit splitters. None of the “right”. ones have ever

Re: [time-nuts] Salvaged OCXO by ar electronique

Hi If you have not already spotted a Vref pin on the unit, your magic 8V pin may be the Vref for the EFC. It also could be “factory use only / do not connect “. There are OCXO’s on eBay in the < $30 range that should do about as well as what the spec sheet shows for the part you have. The

Re: [time-nuts] Interesting 1-60 MHz =/- 50 ppb Stratum-3 TCXO chip

Hi If the idea is to run things standalone, a generic eBay OCXO would work better than these devices. The OCXO would be more stable. It also should be lower noise / better ADEV. If the idea is to lock these up to the TBolt, it’s not at all clear what benefit that would have. Bob > On May 1,

Re: [time-nuts] GPSDO advice

Hi I would guess that the vast majority of folks on the list and an even larger percentage doing the FMT are buying their GPSDO’s on eBay. Which ones they buy and how well the work is very much a “that depends sort of thing”. The crop of devices at low(er) prices changes every 3 to 5 years.

Re: [time-nuts] power supplies

Hi Spend some time on eBay looking for Power Designs bench supplies. They went out of business years ago so they are not a popular item. Thus the price is usually pretty reasonable. I have never seen one that was a switcher…. Bob > On May 1, 2020, at 2:51 PM, jimlux wrote: > > What with

Re: [time-nuts] FE-5680A - Newbie capacitor question

Hi The only way to work out what you have is to find the data sheet on that part. It *should* translate between the manufacturer’s markings and the exact part number. That part number will tell you as much as can be known about the part. Some data sheets are a lot more complete than others.

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