Re: [time-nuts] Cesium Mechanical Chronometer

I believe that attempting to tune any resonator by damping (Q-spoiling) said resonator by adding drag would be a mistake. It would not likely be very effective at tuning, and has great potential for degrading the frequency stability. Hence my preference for injection locking by rocking about an

Re: [time-nuts] Cesium Mechanical Chronometer

I've been looking at M21 photos, trying to decide if it has a single balance wheel, or a pair of contra-rotating balance wheels. I just can't tell. If it's a single wheel, then gently rocking the M21 movement about an axis parallel to that of the balance wheel seems like it could be a viable way

Re: [time-nuts] GPS location inaccuracies from a cell phone

Looks like most of your route was under dense foliage, as well. That could cause GPS signal dropouts. Dana On Sun, Feb 2, 2020 at 11:36 AM Chris Wilson wrote: > > > 02/02/2020 17:28 > > Hopefully not too off topic a question, but GPS experts abound here... > > I am running a tracking

Re: [time-nuts] Digital Pots, wiper noise and fine tweaking oscillators

Perrier, In answer to your 2nd question, I am unaware of any oscillator technology for which tuning the actual oscillator frequency has either (much less both) of instant full response or absolutely zero effect on its frequency drift trend afterwards. Instantaneous full response is generally not

Re: [time-nuts] Digital Pots

Don't "good" OCXOs float the oven stuff and use a separate return pin instead of a GND pin common with the OSC GND pin? Dana On Tue, Feb 4, 2020 at 7:42 AM Bob kb8tq wrote: > Hi > > The great thing about a wire wound pot is that as a voltage divider, it has > a very low temperature

Re: [time-nuts] Pressure sensitivity of Rb vapor cell standards

the rubidium lamp transitions is fairly wide and that the Rb87 > cell is heated and acceptance is also fairly wide-band, it works out > pretty well. > > Maybe I should just take one of my 780 nm diodes and try in the cell > with broken Rb-lamp oscillator, just for fun. > > Cheers, &

Re: [time-nuts] Pressure sensitivity of Rb vapor cell standards

Don't forget that an AO modulator can also be used to tune the frequency over a modest range, (MHz or more), at the cost of the output beam angle's changing slightly as well. Dana On Wed, Feb 19, 2020 at 11:17 AM Attila Kinali wrote: > On Wed, 19 Feb 2020 01:40:56 +0100 > Magnus Danielson

Re: [time-nuts] Pressure sensitivity of Rb vapor cell standards

What's the optimum wavelength for the Rb light source? A laser would certainly have a much narrower linewidth than an LED, provided one can find a laser with the correct wavelength. Many diode lasers have a detector integrated into the same package, making tightly-stabilized output power a snap

Re: [time-nuts] Low Phase Noise Amplifiers

FWIW, at the Arecibo Observatory all our cryogenic LNAs had bias stabilized with active stabilizers based on opamps. Since the opamps do not work at ~15K, bias connections to the drain and gate of the RF FETs were brought out separately from the RF connections, and the opamp circuitry was at room

Re: [time-nuts] Low Phase Noise Amplifiers

measure phase noise of any of the cryogenic amplifiers. Our LNAs mostly have noise temperatures in the range of 2K to 3K, which is roughly 0.03 to 0.04 dB NF. Dana On Sun, Jan 12, 2020 at 3:33 PM wrote: > -Original Message- > From: time-nuts On Behalf Of Dana > Whitlow > Se

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

If anybody knows how to do this, I bet it would be the people who do long-baseline interferometry at millimeter-wave frequencies, such as at the eVLA in New Mexico. Dana On Wed, Jan 15, 2020 at 4:35 PM Attila Kinali wrote: > On Wed, 4 Dec 2019 09:40:34 - > wrote: > > > I'm always being

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

That is true. Is post-processing not an option here? Dana On Wed, Jan 15, 2020 at 5:05 PM Attila Kinali wrote: > On Wed, 15 Jan 2020 16:39:45 -0600 > Dana Whitlow wrote: > > > If anybody knows how to do this, I bet it would be the people who do > > long-baseli

Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

Re cross talk, I'd suggest: Fairly equal levels on all the used outputs, to minimize the effects of crosstalk between them. This is especially important if you're using RG-58 or similar cable, which leaks like a sieve. Crosstalk of this sort will tend to screw up the edges of a PPS pulse,

Re: [time-nuts] IERS leap second bulletins?

blications/Bulletins/bulletins.html > > The current file you want (December 2019) is here: > > ftp://ftp.iers.org/products/eop/bulletinc/bulletinc-058.txt > > The archive for Bulletin C is: > > ftp://ftp.iers.org/products/eop/bulletinc/ > > Bottom line, no leap second

[time-nuts] IERS leap second bulletins?

How does one access the IERS bulletin C (or whatever is applicable these days) for leap second info? Now when I try to do so, I get the following: The requested URL was rejected. Please consult with your administrator. Your support ID is: 11450193631126308915 Well, I am the administrator of my

Re: [time-nuts] PLL suggestions

Don't forget the "regenerative" frequency divider concept, either. At some point you'll need to do some division, and these things seem to have a rep for better phase noise performance than logic-based dividers. Dana On Tue, Dec 31, 2019 at 10:15 AM Dan Kemppainen wrote: > Hi All, > > We've

Re: [time-nuts] Microstepper

Magnus, Why not just clock a good DDS (AD9854) with the reference frequency, and run its I & Q outputs into the motor via suitable LP filters and some power gain? You might need to periodically alternate between two different output frequencies to get the desired rotation speed (as with a

Re: [time-nuts] Microstepper

is after is one to adjust the phase of the output > of > his shiny new (to him) maser. Same name, different beast. > > Bob > > > On Dec 24, 2019, at 9:03 PM, Dana Whitlow wrote: > > > > Magnus, > > > > Why not just clock a good DDS (AD9854) with the ref

Re: [time-nuts] EFOS B Hydrogren maser arrived

Magnus, I hope you'll be keeping a record of frequency drift of your EFOS B over time (not necessarily counting the settling-in period) and making this public. I'd like to compare the numbers with what I remember for the MHM-2010 at Arecibo, which amounted to slowing down by roughly 1E-13 per

Re: [time-nuts] Ultra Stable Rb

Martyn, is there anything special about the design to which you might attribute the low drift? Even if your unit's siblings are not "quite as good", they might still be quite a bit better than the usual run-of-the-mill Rbs. Thanks, Dana On Wed, Apr 8, 2020 at 8:46 AM wrote: > Hi Guys, > >

Re: [time-nuts] Ultra Stable Rb

Bob, what I' was getting at was: what do you do differently 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

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

Seems to me that both GPS receivers and Ligado's transmitters are going to need the "brick-wall" filters. I wonder how lossy such filters will be when sized to fit in handheld GPS receivers, smart phones, and (especially) GPS watches. On the other hand, it may be that many time-nuts will not

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

I've seen PPS ticks as short as 100 nsec from some equipment. Didn't think to try the headphone trick at the time, but am dubious about hearing pulses that short at ordinary pulse amplitudes. Dana On Tue, Apr 21, 2020 at 6:37 AM Bob kb8tq wrote: > Hi > > One of the simplest justifications I

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

Caution: opamps make terrible limiters- their overload behavior is generally ugly and unpredictable. It's much better to use a genuine level comparator, and wire it up so that it has a modest amount of hysteresis. Dana On Fri, Apr 3, 2020 at 6:45 AM Bob kb8tq wrote: > Hi > > The quick way to

Re: [time-nuts] Microsemi XLi SAASM

You could easily do what you want without modifying the receiver, using a 7805 or similar regulator and a pair of bias tees, inserted in the transmission line from the antenna. Dana On Fri, Mar 27, 2020 at 7:33 PM Steve - Home wrote: > I wondered if anyone has a user and/or service manual for

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

When soldering parts with tight pin spacings, don't forget the trick of clearing shorts between adjacent pins using copper braid freshly wet with liquid flux. The message here is: don't panic if you create a short or even a group of shorts while soldering. It happens all the time and is pretty

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

The thing is, the shorter the electrical pulse, the less total energy is available (particularly in the audio frequency range), and no amount of "echoing around" (which is really just a form of filtering) can fix that. So there *are* limits. Dana On Tue, Apr 21, 2020 at 7:49 PM Neville Michie

Re: [time-nuts] potential low-RFI power supply

IIRC the HP3561A goes to 100 kHz. It's a well-built FFT analyzer at heart. Dana On Sun, May 17, 2020 at 4:12 PM Taka Kamiya via time-nuts < time-nuts@lists.febo.com> wrote: > I have an HP audio FFT that starts from sub 1Hz so I can do that when I > get mine. What kind of load shall I use for

Re: [time-nuts] Quick check of a GPS controller oscillator

Is the ProgRock GPS disciplined or a Rb, or is it just a free-running crystal oscillator? And does LH say that the Trimble is locked OK? Unless the PrgRock is GPS disciplined (or is a Rb), it's a pretty safe bet that it has simply grown old and the crystal has aged. And this notion is much

Re: [time-nuts] Model # FE2040B

Gordon, Out of curiosity, what variety of standard is it? Dana On Tue, May 5, 2020 at 10:18 AM Gordon Batey wrote: > Greeting to the timekeepers, > > I have just acquired a Frequency Electronics FE2040B Frequency Standard. > It has been off for a long time. It is mounted on a small chassis

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

Clearly the muQuans clock is a horse of another color from our usual Rb standards. Considering its size and weight, shipping it back to the mfr every few years would be a royal pain, too. I looked over the datasheet and could find no mention of the active atomic species in use. Is it Rb for

Re: [time-nuts] Quartzlock E10-MRX

Taka, There's not much really wrong in making the oven(s) work harder to maintain the desired Rb cell temperatures because of a cooler baseplate temperature. If the thermal design is done well, nothing will run appreciably hotter and most of the electronics will run cooler. However, it is my

Re: [time-nuts] LPRO 101 heat sink question

That's what I did with my LPRO, and it seems to be happy- I've been using it for a couple of years now with no apparent difficulty. Dana On Thu, Sep 10, 2020 at 9:29 AM Jim Harman wrote: > I recently purchased an LPRO rubidium from the auction site. The mounting > surface is covered with a

Re: [time-nuts] GPSDO "accuracy"

Not sure what you mean by "accuracy over a 10 sec interval". If you mean (in)correctness of frequency averaged over a given 10 sec interval, it's more like a few parts in 10^9. But if you mean stability of frequency without regard for its correctness, you might see your 2 parts in 10^12 in at

Re: [time-nuts] Chelsea Chronoquartz dividers

It may be that he's looking for info on how to drive the stepper motor(s), such as pulse sequences etc. Dana On Fri, Sep 11, 2020 at 2:59 PM Graham / KE9H wrote: > 2^22 = 4,194,304 > So divide by two, 22 times in a row to get to 1 Hz. > --- Graham > > > On Fri, Sep 11, 2020 at 12:42 PM Bill S

Re: [time-nuts] WWVB Dephaser Question

Direct IQ demodulation to zero-IF is indeed subject to problems from LO leakage into the mixers. Said leakage will displace the center of the IQ plot away from the origin, which then requires correction later on, which is a pain to do well. A pretty good way to deal with all this is to

Re: [time-nuts] ! PPS Source

Tom, I for one would like to see what you have down that "rabbit hole" regarding the new architecture of the CNS clock, that does not do variable delay line sawtooth corrections. Dana On Sat, Aug 15, 2020 at 1:41 PM Tom Van Baak wrote: > Hi Ed, > > > I'm also aware that some people have

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

Scott, Was anybody even making 3V GPS LNAs 20 years ago? Dana On Fri, Aug 28, 2020 at 6:48 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

Re: [time-nuts] eLORAN 99600 monitoring at 100 KHz

Paul, What time of day did you measure that signal strength? And what are the characteristics of the "standard marine preamp"? Most importantly, what field strength corresponds to 1000 uV output from it? Thanks, Dana On Fri, Aug 14, 2020 at 12:17 PM paul swed wrote: > Hello to the group. >

Re: [time-nuts] eLORAN 99600 monitoring at 100 KHz

g and deduce the actual field strength. > Regards > Paul > WB8TSL > > On Fri, Aug 14, 2020 at 4:08 PM Dana Whitlow > wrote: > > > Paul, > > > > What time of day did you measure that signal strength? > > > > And what are the characteristics of the &

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

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 of up to 10's of nsec p-p. And I also know that the PRS-10 (and probably

Re: [time-nuts] WWVB PM Time Questions

Try looking up the "Costas Loop" and the "frequency doubling loop". They should give you some ideas of how to generate a stable local reference. Dana On Tue, Jul 21, 2020 at 7:47 PM wrote: > I want to decode the WWVB time information using the BPSK information > that is broadcast. I will use

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

Sudden changes in amplitude or phase can also be a local phenomenon, like a loose joint in a rain gutter system for example. One would think that such a problem in a high power transmitter installation would be setting off alarms all over the place and probably automatically tripping the

Re: [time-nuts] 1PPS questions

Dave, I'd suggest putting about a 10-dB RF attenuator in the line between the PPS source and your 5372A. That should bring the level down to about 2V. Dana On Wed, Jul 1, 2020 at 10:44 PM VE7HR wrote: > Are there any suggested method to reduce your 1 PPS signal to a safe level > for your

Re: [time-nuts] 1PPS questions

I like Bob's suggestion about using an L-pad. Even if the line driver *is* happy driving 50 ohm line (which I was admittedly assuming), the L-pad approach will keep the driver cooler which will likely reduce warmup drift of its propagation delay as well as extend its lifetime. Dana On Thu, Jul

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

If compactness is needed and you're operating in anything like a 1 g field, I think that it will be impossible to do a spring suspension that is both compact and effective down to the milli-Hz level (or less). It might be worthwhile doing a compensation scheme based on a 3-axis accelerometer (one

Re: [time-nuts] Precise Pendulum

John, Everything I've read on the subject says that "spooky action at a distance" does *not* provide for FTL communications. Sorry to disappoint- I'd like to see it, too. Dana On Sun, Jun 28, 2020 at 7:47 AM John Moran, Scawby Design < j...@scawbydesign.co.uk> wrote: > Interesting ... > >

Re: [time-nuts] Frequency division by 81

Can you stand a few 10's of nano-Hz error in the 162 kHz signal? If so, a 48-bit DDS can get you that close to 162 kHz when the 10 MHz is right on. However, dealing with the off-the air signal would be problematic as has been pointed out, not to mention the added complication of the signal

Re: [time-nuts] Frequency division by 81

I've read that the so-called regenerative frequency divider has exceptionally low phase noise. You could cascade four of them, each dividing by 3. It's not the simplest thing in the world, but might yield really good phase noise performance. Back when I worked at TEK on the 2710 (low-cost SA)

Re: [time-nuts] ThunderBolt question

I'd like to point out that mismatches at the ends of an antenna cable *can* cause trouble. When both ends are mismatched, each bit of detail in the signal gets partially reflected back and forth, each time delayed by the round trip propagation delay in the cable, and so you have something like

Re: [time-nuts] ThunderBolt question

Robert, One does not know what the RF input impedance of the unit is unless one measures it (very carefully at low levels) with a VNA or similar instrument. Just 'cause some manufacturer says that it's 50 ohms does not mean very much- it's not uncommon to see actual impedances off by a factor of

Re: [time-nuts] ThunderBolt question

more. Given the coding of GPS signals which allows several > satellites to share a common frequency band, that is not going to be much > of > a problem. And if only one end of the path actually is 75 ohms, then there > won't be a delayed signal. > > Tom Holmes, N8ZM > > -Origi

Re: [time-nuts] ThunderBolt question

I must take issue with John's statement that "impedance matching is easy". It's easy only in the case of very limited bandwidth and if you are willing to ignore such issues as getting good IMD performance, good noise performance, and good broadband AC stability. The last item is critically

Re: [time-nuts] ThunderBolt question

Yes, to wring the last ounce of performance out of GPS takes attention to > the details, but don’t lose sight of how it was designed to work for users > in less than optimum (military field operations) in the first place. > From Tom Holmes, N8ZM > > > On Jun 6, 2020, at 7:14

Re: [time-nuts] ThunderBolt question

mes, N8ZM > > -Original Message- > From: time-nuts On Behalf Of Dana > Whitlow > Sent: Saturday, June 06, 2020 8:52 AM > To: Discussion of precise time and frequency measurement < > time-nuts@lists.febo.com> > Subject: Re: [time-nuts] ThunderBolt question &g

Re: [time-nuts] ThunderBolt question

Wes, it sounds like you're in pretty good shape with one thing that concerns me. Unless your transmission line is long enough to have substantial loss, that 40 dB gain figure seems awfully high and you may find yourself overloading the front end of your receiver. Most modern receivers are

Re: [time-nuts] ThunderBolt question

pefully Ligado won't be an issue. We'll have to see if their > technical expertise is as good as the PR and lobby lawyers are. > > Wes > > On 6/6/2020 8:49 AM, Dana Whitlow wrote: > > Wes, it sounds like you're in pretty good shape with one thing that > > concerns

Re: [time-nuts] time sync by moonbounce

I also bought my copy of "Uplink-Downlink" through Amazon but had better luck. The cover photo is in color, not quite as sharp as I would have preferred but has no apparent compression artifacts. The text inside is of good quality- nop complaints in this department. However, the photos inside

Re: [time-nuts] WWVB PM Time Questions

t; If I can get the WWVB signal looking clean enough that will probably be > my starting point. > > Ray, > AB7HE > > Original Message > Subject: Re: [time-nuts] WWVB PM Time Questions > From: Dana Whitlow > Date: Mon, July 27, 2020 4:20 pm > To: D

Re: [time-nuts] WWVB PM Time Questions

That phase reversal when the waveform is not at a zero crossing probably adds appreciably more high frequency content than a phase reversal at a zero crossing. In ham parlance, I'd say it would introduce pretty severe "key clicks". Have you considered writing a program to generate the right

Re: [time-nuts] Double balanced mixer question

Peter, it* is* too simplistic. It's very likely that the 10 MHz is also being *phase* modulated at 1 Hz, and clipping will not remove that. Dana On Thu, Jul 23, 2020 at 5:23 PM Peter McCollum wrote: > This may be too simplistic, but you could clip it with a limiter to remove > the amplitude

Re: [time-nuts] PRS10 not locking to 1PPS

n. > > Thanks for your help > > Erik (PE1RQF) > > > > -Original Message- > From: time-nuts On Behalf Of Dana > Whitlow > Sent: maandag 4 januari 2021 21:02 > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts]

Re: [time-nuts] HP 5065 Rb update

Paul, Would it be feasible to add a smaller winding around the outside of the existing C-field winding, and drive it from something other than the crude rheostat circuit? Then you could make finer adjustments than the existing driver permits, and would rely only on the existing driver to provide

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

I wonder if it might be good to power up the ion pump with the heaters cold, then after the ion current trails off to nil, begin operating the filaments at very low voltage (and all other voltages off except for the ion pump) and gradually ramp the the filament voltages up towards normal operating

Re: [time-nuts] HP 5065 Rb update

cal value using that board. Then tune the device by other means. > > Bob > > > On Dec 7, 2020, at 2:31 PM, Dana Whitlow wrote: > > > > Paul, > > Would it be feasible to add a smaller winding around the outside of > > the existing C-field winding, and drive it f

Re: [time-nuts] SMPS or conventional?

A properly-tuned PID system does not cycle! Dana On Mon, Dec 21, 2020 at 6:49 PM Bob kb8tq wrote: > 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.

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

The optical sensing of despoint by dew-on-the-mirror was used in a device designed at the Whirlpool Research labs in St. Joseph, MI. It apparently never made it into production, but a number of units were built and sold or given away (I'm not sure). I know about this because I interned at the lab

Re: [time-nuts] HP105B Help

If you're thinking it's the 10811, here's something to try: Arrange to measure output frequency, and tune voltage, and put the curves up on a dual-trace o'scope. If the output frequency fluctuations correlate in the correct direction of the tune voltage fluctuations, then the problem is probably

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

It just occurred to me that one of the TinySA's could be handy for tracking down leaks like this. Dana On Sun, Dec 27, 2020 at 8:02 AM Bob kb8tq wrote: > Hi > > If you can hear it on your radio with your normal antenna …. it’s leaking. > > If you want to track it down, normal radio frequency

Re: [time-nuts] L1/L2 survey antenna $125 new

Thanks, Bob. I zoomed in on the image that shows the connector without the cover, and it sure looks like a female connector to me (contradicting what the SparkFun description says). I could not determine which handedness applies to the threads, however- not quite enough resolution in the photo.

Re: [time-nuts] L1/L2 survey antenna $125 new

I quote the description on the SparKfun page via the WIndows clipboard: "Note: This antenna has a TNC Male RP connector found on nearly all surveying antennas. We recommend a TNC Male RP to SMA adapter or cable when

Re: [time-nuts] L1/L2 survey antenna $125 new

gt; Tom Holmes, N8ZM > > -Original Message- > From: time-nuts > On Behalf Of Dana Whitlow > Sent: Friday, November 13, 2020 3:17 PM > To: Discussion of precise time and frequency > measurement > Subject: Re: [time-nuts] L1/L2 survey antenna $125 > new > > Thank

Re: [time-nuts] power supply for Z3801

For heaven's sake don't try to power equipment from a trickle charger. The thing may be more like a current source than a voltage source. Also it may not be isolated from the safety ground, which would rule out connecting several in series. A good power supply is so crucial to happiness and

Re: [time-nuts] ES100 Atomic Clock Receiver Back in Stock

Just to be clear, is the ES-100 the receiver used in the Ultratomic clocks made by Lacrosse? Dana On Thu, Oct 29, 2020 at 7:38 AM Ben Hall wrote: > Good morning all, > > Universal Solder is showing the ES-100 WWVB BPSK clock kits back in > stock. Just put me one on order. :) > > < >

Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

And for the serious low-noise enthusiast, a side benefit of cooling to cryogenic temperatures like 15K or so is that the thermal conductivity of copper is something like 25X what it is at room temperature. Dana On Fri, Oct 30, 2020 at 9:11 PM Mark Sims wrote: > > And (if I remember the

Re: [time-nuts] SMPS or conventional?

I prefer the use of non-switching power supplies, in part because I am forced to use indoor receiving antennas not very far from my equipment setup. However, one of my Rb standards, an used L-Pro which I bought from another ham, came with a SMPS and I've never noted any particular problem. So,

Re: [time-nuts] Holiday Hydrogen Glow!

It appears that the pink glow is reaching at least several inches from the discharge region. Am I correct in thinking that it stems from recombination of electrons and protons into neutral atome? And regardless of the precise mechanism, do any significant number of the glow-causing species make

Re: [time-nuts] Leakage, tinySA

Another data point: My newly-received TinySA has a big birdie at 10 MHz, which is a disappointment since I had hoped to use the unit as a sniffer to track down leaks in my 10 MHz distribution system. This birdie in the TinySA persists even when nothing is connected to the input and does not vary

Re: [time-nuts] Leakage, tinySA

t; looking into to see if you have a sub-par copy. > > Dan > > > > > On 1/16/2021 12:00 PM, time-nuts-requ...@lists.febo.com wrote: > > Date: Sat, 16 Jan 2021 05:45:19 -0600 > > From: Dana Whitlow > > To: Discussion of precise time and frequency

Re: [time-nuts] Leakage, tinySA

Hal, my 10 MHz birdie is at a level of about -95 dBm, which puts it a little more than 10 db above the noise floor in 3 kHz BW. I've found that the "spur removal" function sometimes works, but not always, if I change the IF frequency setting to 433.9 MHz. It's mostly bimodal behavior- sometimes

Re: [time-nuts] Leakage, tinySA

I'm aware of. Also they have the best > price in US you can find for obvious reasons. FWIW I don't have spurs at > 10MHz. > > Bill in AZ > > On Sun, Jan 17, 2021, 5:35 PM Dana Whitlow wrote: > > > Hi Dan, > > > > I remember seeing the list of checks to make r

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

Hal, I just ordered a "TinySA", largely with leak tracking in mind. I won't have it until about mid month (January), but have high hopes for it. I'm planning to use it with a small single-turn electrostatically-shielded loop, which I believe will yield adequate sensitivity for the purpose while

Re: [time-nuts] PRS10 not locking to 1PPS

Erik, the PRS-10 does have provisions for changing the internal synthesizer's "ratio", which could provide a way of getting an essentially fresh start on aging. There's a big table of values somewhere in the documentation (but not necessarily in any convenient order). My old PRS-10 is getting

Re: [time-nuts] "Q for dummies"

If anybody can even approach doing justice to the Q concept, including why it matters, in just two sentences, that person will have definitely earned the "Qulitzer prize" in technical journalism. Here's my entry: "A circuit's Q is closely related to its internal energy losses compared to

[time-nuts] Re: PRS-10 heatsink design

I mount my PRS-10 vertically (so that the channels between the fins are vertical), with the connector on top. This orientation was chosen simply for best access to the connector, but yields heat sink temperatures down around 45C to 50C. The unit is open and fully exposed to the air. I run it at

[time-nuts] Re: Help ID'ing Frequency Standard

John, At least you seem to have enough info to power it up safely. From its evident complexity, I think it might well be a Rb standard. Dana On Sun, Jun 6, 2021 at 9:23 AM John Ackermann N8UR wrote: > Looking through the junk box I came upon a metal box labeled: > > Frequency Standard >

[time-nuts] Re: LH "No usable sats"

I believe that your problem still remains somewhat unsolved, as you should be getting good coverage over most of the compass except for the northern "doughnut hole". Instead, you're apparently getting coverage only to the W through NW. BTW, when using a T'Bolt I have my AMU thresholds set at

[time-nuts] Re: GPS antenna distribution???

A resistive splitter has essentially no useful port-to-port isolation, in addition to the excess splitting loss problem. For this reason, resistive splitters are usually used only when very broad frequency ("DC to daylight") coverage is needed. Many RF splitters are of the Wilkinson variety, or

[time-nuts] Re: GPS antenna distribution?

Could be that north-facing window/reflector is actually helping you a bit with signals from the south coming through the house. Stranger things have happened ... Dana On Mon, Jun 28, 2021 at 4:03 PM wrote: > Thanks guys. Opened a lot of things to think of. Makes me wonder how I > get any

[time-nuts] Re: GPS antenna distribution?

Or, it could be that the UV coating is really a multi-layer dielectric coating, not metal at all, in which case it would have negligible impact on L-band signals. Dana On Mon, Jun 28, 2021 at 6:17 PM Dana Whitlow wrote: > Could be that north-facing window/reflector is actually helping

Re: [time-nuts] Daft idea with the National Grid

Not daft at all, Andy. Closely related would be measurements of phase change between near the switched load and far away, over a stretch of a few system time constants. This would be more challenging, but perhaps doable. Dana K8YUM On Sun, Feb 7, 2021 at 3:44 PM Andy Talbot wrote: > The UK

[time-nuts] Re: Water in connectors

Ole, You did not mention whether this timing anomaly is periodic or steadily growing. That information could be of considerable diagnostic significance. Dana On Sat, Mar 27, 2021 at 6:08 AM Ole Petter Ronningen wrote: > Hi, All > > I am trying to chase down a 2-3-4 ns/day "anomaly" in a

[time-nuts] Re: Water in connectors

take the maser out of the equation.. (and reseal the connectors > properly) > > > > 27. mar. 2021 kl. 14:04 skrev Dana Whitlow : > > > > Ole, > > > > You did not mention whether this timing anomaly is periodic or steadily > > growing. > > That informati

[time-nuts] Re: The Collapse of Puerto Rico’s Iconic Telescope [April 5th, 2021 New Yorker]

Arecibo's long-standing maser (Symmetricom MHM-2010) died right at the end of 2018. In communications with the mfr it came to pass that "repair" was deemed to be economically infeasible. so the observatory fell back on a FS725 locked to PPS from a CNS Clock II, both of which I had purchased a few

[time-nuts] Re: Ublox NEO-M8T-0-10​as a LO question

Chris, It may be that the modulation and subsequent demodulation scheme used for satellite TV and the like is rather more robust than many people give it credit for. Dana On Wed, Mar 31, 2021 at 7:09 AM Chris Wilson wrote: > Hello everyone > > Monday, March 29, 2021 > > Thanks for the

[time-nuts] Re: Ublox NEO-M8T-0-10​as a LO question

ons, and the LB GPSDO > being moderately good close in. Phase noise out beyond a few kHz goes > more or less unnoticed on SSB > > Andy > www.g4jnt.com > > > > On Wed, 31 Mar 2021 at 13:35, Dana Whitlow wrote: > > > Chris, > > > > It may be that the

[time-nuts] Re: The Collapse of Puerto Rico’s Iconic Telescope [April 5th, 2021 New Yorker]

I have not yet heard what GB wants to do, but if it's long range work (return time of 10's of sec or longer), the problems related to T/R switching, Tn degradation of the receiver, etc, get a lot more tractable than one might suppose. At Arecibo, the S-band radar was intended solely for long

[time-nuts] Re: Sparkfun lists SA.35m

"rubidium laser" ??? Dana On Sat, Apr 3, 2021 at 2:15 AM Poul-Henning Kamp wrote: > I know it's not a particular outstanding atomic clock, but I was still > surprised to see that Sparkfun lists the SA.35m for $1995... > > https://www.sparkfun.com/products/14830 > > Not in stock

[time-nuts] Re: Sparkfun lists SA.35m

4/3/21 4:22 AM, Dana Whitlow wrote: > > "rubidium laser" ??? > > > > Dana > > I don't know about the MAC, but the CSAC uses a VCSEL to shine through > the gas cell. > > The MAC is a pretty big thing compared to the CSAC - it's in the usual > 2x2"

[time-nuts] Re: Water in connectors

predictably that only served > to uncover more questions than it answered.. > > > 27. mar. 2021 kl. 17:39 skrev Dana Whitlow : > > > > My own belief is that almost everything can be blamed on GPS, but then > much > > if not > > most is my own fault for us

<    1   2   3   >