[time-nuts] Re: Tuning a GPSDO loop for optimal disturbance handling

Eric, Do the observed DAC steps correspond in polarity to the observed frequency changes, or just the reverse? That's a key determination to make in placing blame, for it tells you whether the DAC steps are causative to the frequency changes, or rather the PLL's reaction to problems in, say, the

[time-nuts] Re: HP 5065A, no 2nd harmonic.

TVB, I'm interested in the nitty-gritty of this problem and would appreciate it if you OK this thread's being kept on the group. Dana On Thu, Nov 18, 2021 at 6:58 PM Jared Cabot via time-nuts < time-nuts@lists.febo.com> wrote: > Hi, > Your help is appreciated. We can keep this on-list for now

[time-nuts] Re: FS740 Thoughts?

Bob, I seem to remember reading in the manual on the PRS-10 where they expounded at length about how they took great pains to make the unit work well with typical noisy GPS PPS input. I'm using a CNS Clock II as my primary GPSDO, checking phase slippage with respect to my PRS-10 to make decisions

[time-nuts] Re: FS740 Thoughts?

Poul, You did not really answer the basic question: "Does the 2.5 Hz (or 5 Hz if applicable) C-field reversal cause the 2-sec bump in the ADEV plot for the PRS-10?". BTW, some radio hams are involved with microwave and even MMW communications between mobile stations, and I'd bet they benefit

[time-nuts] Re: FS740 Thoughts?

But if you can stand the ADEV hump around 2 sec, the PRS-10 is delightful. BTW, the ordinary factory new PRS-10 does provide for direct locking to 1 PPS, but many of the available surplus units had that feature removed. Tne new PRS-10's sold for years for $1595, but I see that it has gone up to

[time-nuts] Re: GPS Elevation Mask Values.

Dan, in recent years I've read that DOD (or some such agency) has been running spoofing tests here and there, but always in remote thinly-populated areas (for what should be obvious reasons). As to why not all your receivers exhibit the "finger", I point out that the appearance of a GPS satellite

[time-nuts] Re: GPS Elevation Mask Values.

In fact, I believe that the satellite positions shown on screen plots are those calculated from almanac data. My reasoning is that most GPS receivers seem able to put up such plots first thing after turn-on, before ephemeris data from even a single satellite is available. IMO, if the almanac

[time-nuts] Re: GPS Elevation Mask Values.

Dan, could it be that you have a spoofer in the area? Dana On Sun, Nov 14, 2021 at 4:27 PM Dan Kemppainen wrote: > Hi, > > Still trying to sort out the cause of that 'finger' of signal. > > Hooked up two more different GPS modules. A ZED-F9P, and a Jackson Labs > LTE-LITE eval board. > > The

[time-nuts] Re: GPS Elevation Mask Values.

I own at least two Garmin handhelds that park out-of-service sat symbols at due north on the horizon. But they don't do anything like that finger. Dana On Wed, Nov 10, 2021 at 9:30 AM Bob kb8tq wrote: > Hi > > Your GPS antenna does not have a clue where signals are coming from. The > only >

[time-nuts] Re: GPS Elevation Mask Values.

Hal, that looks suspiciously like the fickle finger of fate to me. Dan, since you have good low-angle coverage I might suggest setting the elevation cutoff as low as 10 deg or so and taking a look at the results for a few weeks. Then start raising the elevation cutoff and repeating the

[time-nuts] Re: Rubidium oscillator : pack it in styrofoam or attach it to a heath-sink?

I wonder what the detailed thermal model of telecom Rb's looks like. I cool my PRS-10's hear sink surface to ~55C with a heatsink, but parts of some other surfaces of the package run several degrees hotter. This rather puzzles me, and worries me. Dana On Tue, Oct 5, 2021 at 10:46 AM Bob kb8tq

[time-nuts] Re: When did computer clocks get so bad?

Alec, I seem to perceive that PC clocks have gotten quite a bit better since their early days. What do others think? Dana On Wed, Sep 29, 2021 at 3:10 PM Alec Teal wrote: > Hi there, > > I have a question and I cannot think of anyone better to ask, for a > project we need to time some things

[time-nuts] Re: Death of a Capacitor

One other thing to consider with LDOs: some types can go unstable and oscillate with the wrong (combination of) capacitors on input and output. So any time you design in an LDO, it is important to closely scrutinize the datasheet and application note(s) and heed their warnings. Unless you like

[time-nuts] Re: ammonia, cesium, masers, etc.

My dad worked in the absorption air conditioning field using ammonia and water, and he once told me that ammonia-water was hell on aluminum copper points, or even aluminum tubing that had impurities in the form of tiny copper flakes in it. As to dry ammonia, intuition suggests to me that things

[time-nuts] Re: in-ground clock room

It may be that the time constant of eddy current damping would be too limited by the inavailability of sufficiently good conductors (ar room temp, anyway). To get really long time constants one basically needs superconductivity somewhere in the system. Dana On Sat, Sep 11, 2021 at 11:54 PM Tom

[time-nuts] Re: in-ground clock room

One might also consider mounting smaller items inside the cylinders of the engine block, to get the most out of its thermal mass. Dana On Thu, Sep 9, 2021 at 11:03 AM Joseph Gwinn wrote: > On Thu, 09 Sep 2021 03:30:35 -0400, time-nuts-requ...@lists.febo.com > wrote: > Re: time-nuts Digest,

[time-nuts] Re: in-ground clock room

Tom, Andy brings up good points, especially about water leaks. Are you familiar with "Whitlow's 5th law" (which can be summarized as "everything leaks")? Dana Whitlow On Thu, Sep 9, 2021 at 7:29 AM Andy Gardner, ZL3AG via time-nuts < time-nuts@lists.febo.com> wro

[time-nuts] Re: in-ground clock room

It seems to me that in order to derive much thermal stabilization, the *top* of the space would need to be several feet underground (depending on geographic location). And I think that the means for human access would likely "spoil the broth" unless fairly extreme measures were taken. Wouldn't

[time-nuts] Re: thermodynamics of time keeping

Perhaps the author is trying to include Schmitt triggers to sort of emulate mechanical escapements. I've occasionally used the things (Schmitt triggers) to help square up sinewaves, but never in a case where I was concerned about stability or jitter. BTW, how do three inverters constitute a

[time-nuts] Re: Affordable 160 GHz Sampler

I'm curious- is this a realtime sampler, or is it one of these things like early sampling 'scopes used? Dana On Wed, Sep 1, 2021 at 1:10 PM Mike Monett wrote: > Conventional samplers for home brewers usually go to 1 GHz. The SD-32 > sampler for the Tektronix 11801C mainframe goes to 50 GHz.

[time-nuts] Re: BNC connectors for the distribution of frequency or time...

Another point should be mentioned: Many inexpensive RF products use floating BNC connectors (those with shells that are insulated from the bulkhead in which they are mounted). These are virtually guaranteed to be common-mode leaks, and should be avoided like the plague. Nobody will admit to

[time-nuts] Re: Query about List and about 10 MHz Distro

n coax for 10MHz distribution > Removes all possibility of ground loops > > Andy > www.g4jnt.com > > > > On Sun, 29 Aug 2021 at 15:22, Dana Whitlow wrote: > > > I believe that a significant problem in my case was not leakage through > the shield, > > but &

[time-nuts] Re: About 10 MHz Optical Distro

Paul is right, and it can be difficult to figure out which cable works well at a given wavelength and which connector type is which. A phone conversation with an applications person at the cable supplier ought to help avoid any of the traps At the Arecibo Observatory we had some bad experiences

[time-nuts] Re: Query about List and about 10 MHz Distro

8/28/2021 08:26 PM, Bob kb8tq wrote: > >> Hi > >> > >> Anything you do that has a bunch of 10 MHz cables running out from here > or there > >> will impact your ability to listen to WWV at 10 MHz :) Other than > killing all the sources, > >> there

[time-nuts] Re: Query about List and about 10 MHz Distro

nch of 10 MHz cables running out from here or > there > will impact your ability to listen to WWV at 10 MHz :) Other than killing > all the sources, > there is no silver bullet. > > Bob > > > On Aug 28, 2021, at 7:57 PM, Dana Whitlow wrote: > > > > Bob, my

[time-nuts] Re: Query about List and about 10 MHz Distro

This *assumes* that there is a crossover somewhere practical between > the fiber noise and the noise on the optical gear. You should be able to > work out what it is with some fairly normal phase noise or ADEV testing. > > Bob > > > On Aug 28, 2021, at 3:03 PM, Dana Whitlow wrot

[time-nuts] Re: Query about List and about 10 MHz Distro

I was looking for something similar about 18 months or so ago. Although I haven't taken any action yet, I concluded that one could do a nice job for under $200 per segment, including the transmitter and receiver modules and lots of connectorized multimode fiber. What I *don't* know is what the

[time-nuts] Re: Leviton VTP24 Is this Time Accurate enough?

If my watch were that bad, I'd toss it out and go shopping for a new one. I wonder if Leviton offers a version with an external ref input. Dana On Fri, Aug 27, 2021 at 12:12 AM D. Resor wrote: > I inquired with Leviton as to the accuracy of the VTP24 24 Hour > Programmable > Timer with DST. >

[time-nuts] Re: uncertainty/SNR of IQ measurements

he other. > > --- Graham > > == > > On Thu, Aug 26, 2021 at 4:43 PM Dana Whitlow > wrote: > > > Hi Jim, > > > > I think the best way is to view the signal as a phasor, with any > > noise present adding a > > random trajectory (a fuzzball) to the ti

[time-nuts] Re: uncertainty/SNR of IQ measurements

Hi Jim, I think the best way is to view the signal as a phasor, with any noise present adding a random trajectory (a fuzzball) to the tip of the signal vector. Conceptually speaking, this eliminates needing to worry about the distribution of power between I & Q, etc. It lets you view the whole

[time-nuts] Re: Comparison/evaluation of u-blox timing receivers

Thanks very much, John. Dana On Mon, Aug 23, 2021 at 8:52 PM John Ackermann N8UR wrote: > In 2020 I did an extensive evaluation of the timing ability of the > u-blox LEA-M8F, NEO-M8N, NEO-M8T, NEO-M9N, ZED-F9P, and ZED-F9T. The > work was made possible by support from the HamSci consortium >

[time-nuts] Re: Efratom LPRO-101 Rubidium question....

s of a GPSDO and the Rb > >under test using a simple quadrature demodulator, with the I & Q outputs > >displayed on a 2-chan DSO. > > Can you explain what you do? Do you just connect the two 10 MHz signals > to the input of the demodulator? > > Robert > > > On 08/

[time-nuts] Re: Efratom LPRO-101 Rubidium question....

; > > On 8/23/2021 3:30 AM, time-nuts-requ...@lists.febo.com wrote: > > Message: 4 > > Date: Sun, 22 Aug 2021 10:16:56 -0500 > > From: Dana Whitlow > > Subject: [time-nuts] Re: Efratom LPRO-101 Rubidium question > > To: Discussion of precise time and frequency

[time-nuts] Re: Efratom LPRO-101 Rubidium question....

C'mon guys- when you speak of a frequency error in Hz, you should also specify "at what frequency" *in the same breath*. Or better yet, always specify frequency errors in relative terms. Hundreds of Hz at 10 Mhz is unthinkable for a Rb. Even at 8.2 GHz, 100 Hz error is about 12E-9, which is

[time-nuts] Re: Testing a GPS mag mount antenna

I love Dan's idea, with one caveat. The transmission through a powered-down LNA is an unknown, probably even to the manufacturer. Thus comparing output signal levels with power on or off is pretty meaningless. But his test with power on should be a great way to get some clue that the antenna is

[time-nuts] Re: Testing a GPS mag mount antenna

Skipp, Several responders have correctly referred to the "noise floor", but I believe that none have said what level that is. And it's not trivial to say so, either, because it is dependent on the extent to which the antenna under test sees the sky and ignores blackbody radiation from the

[time-nuts] Re: Antenna return loss

Andy, Good point, up to a point. But even if the antenna's amplifier itself has a good return loss, cheap cables like RG-174 are pure garbage and could be doing just about anything along their length. And if the bottom end connector is put on by a person without training and the correct

[time-nuts] Re: Trimble GSPDO - ISSUE

y rarely hit a 14 db return loss spec in any case. Indeed > there are a lot of attenuators out there that don’t get to 14 db at 1.5 > GHz. > > Trimble did a *lot* of testing before they put the F connector on the > TBolt. > They could find no impact at all. > > Bob >

[time-nuts] Re: Trimble GSPDO - ISSUE

Most general purpose passive splitters for the L-band regime are essentially variations on the Watkinson splitter, which provides good isolation between the output ports, if (and only if) the input port is driven from a matched source. So if your GPS antenna, whether active or passive, has a good

[time-nuts] Re: GPS antenna question

I think there might be a down side to using more sensitive GNSS receivers, which is that such a receiver will be willing to include more impaired signals in its time and/or position solutions, leading to poorer overall accuracy. Does anybody know? I certainly concur that good antenna siting is

[time-nuts] Re: Thunderbolts

-10 you get that hump in the ADEV. I’m not saying that it’s > the > end of the world, but it really does bug me that it’s there …. > > Bob > > > On Jul 20, 2021, at 10:03 PM, Dana Whitlow > wrote: > > > > Bert, remember that I need a very long locking loop time c

[time-nuts] Re: Thunderbolts

Bert, remember that I need a very long locking loop time constant setting in order to smooth out GPS noise, so in a sense the GPSDo is *almost* in a holdover state anyway, all the time. Probably the smartest thing for me to do is to buy a spanking new PRS-10, with the PPS locking feature present.

[time-nuts] Re: Thunderbolts ...

My experiences with the T'Bolt have not been entirely satisfactory. If I set the loop lime constant long enough to get a satisfying smoothing of the GPS noise (a few hundred seconds), then the thermal sensitivity of the VCXO on the T'Bolt rears its ugly head and I see a lot of my HVAC system

[time-nuts] Re: Thunderbolts ...

Agreed, Ziggy. I'm actually thinking (a little bit) about getting a Thunderbolt E. But the price does kind of hurt. Dana On Mon, Jul 19, 2021 at 1:08 PM Ziggy wrote: > $650 for the _starter_ kit - $124 for the carrier board with module. So > I'd say that's affordable. But the ±7us over a

[time-nuts] Re: Z3801A Temperature

Hal, in cases where it is physically applicable, the temperature rating is generally that of the flange which is intended to be bolted to a heat sink. Dana On Mon, Jul 19, 2021 at 7:30 AM Hal Murray wrote: > > I have one sitting on a shelf. No air-conditioning. The top plate is > warm, >

[time-nuts] Re: Thunderbolts ...

t; > These guys: > > https://novotech.com/products/timing-modules.html < > https://novotech.com/products/timing-modules.html> > > At least have a listing suggesting you can buy a Thunderbolt E. > > Bob > > > > On Jul 17, 2021, at 3:28 PM, Dana Whitlow wrote: > &g

[time-nuts] Re: Thunderbolts ...

Dave, The usual source for old used Thunderbolts is either on eBay, or private sales by individuals. I've twice now requested a quote for a new model from Trimble, and they did not even bother to respond. Perhaps there are distributors, but if so I haven't been able to identify any. Dana On

[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?

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

[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: 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: time-nuts Digest, Vol 201, Issue 24

Dave, you just did it yourself. So there! Dana On Thu, Apr 15, 2021 at 7:39 AM Dave B via time-nuts < time-nuts@lists.febo.com> wrote: > Someone used 'php' and 'secure' in the same sentence? :-) > > Dave G8KBV > > > On 15/04/2021 08:30, time-nuts-requ...@lists.febo.com wrote: > > php =

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

Jim, how large is the Goldstone antenna to which you referred? Dana On Tue, Mar 30, 2021 at 4:01 PM Lux, Jim wrote: > On 3/30/21 6:40 AM, Wes wrote: > > Was a pity. China's FAST is receive only. I believe that leaves > > Green Bank as the biggest transmitting telescope. > > More likely the

[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: 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

[time-nuts] Re: Water in connectors

and-dirty check, so a months is not in the cards > - but that second antenna/receiver is climbing on my list of priorities, in > imminent danger of surpassing «doing nothing on the couch»! :) > > > 27. mar. 2021 kl. 16:52 skrev Dana Whitlow : > > > > Ole, > > >

[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: 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

Re: [time-nuts] Grandfather clock sync'd to 1PPS (from time-nuts Digest, Vol 200, Issue 4)

Philip, You and I are definitely "in sync" regarding cheating to alter the pendulum motions! I had a very similar thought for effectively making the pendulum based system into sort of a VCO, except that instead of a metal plate, use a small Nd magnet polarized vertically, stealthily-attached to

Re: [time-nuts] World's most precise.... wall clock

Hal, The older (and probably the newer models, too) Trimble Thunderbolt GPSDOs have a user-adjustable time constant accessible via the serial port using a program like "Tboltmon.exe" (from Trimble). I suspect that "Lady Heather" may also do this. I am fortunate in owning a still functioning

Re: [time-nuts] Old Crystal.

easurement > setup? Is there something that will give more accurate results, given > the equipment on hand? Certainly the Q value seems unreasonably high, > and Rs seems quite low. However, these are large low frequency > resonators (being 25mm in dia.). > > > Thanks, > Dan &g

Re: [time-nuts] Old Crystal.

Blue LEDs under Nixie tubes might have a deeper purpose than appearance- they can also help the Nixie tubes get started upon turn-on (especially if they're getting old). I once stayed in a hotel room whose light switches had neon indicators to help one find them in the dark, and the one near the

Re: [time-nuts] U-blox teaser

Thanks for the link, Bob. I got to know both Victor Zhang and Mike Lombardi during my stay at Arecibo, but to my regret have never met either in person. Dana On Sat, Feb 27, 2021 at 6:01 PM Bob kb8tq wrote: > Hi > > > > > On Feb 27, 2021, at 11:18 AM, Dana Whitlow >

Re: [time-nuts] U-blox teaser

b 27, 2021 at 9:08 AM Bob kb8tq wrote: > Hi > > > > > On Feb 27, 2021, at 9:41 AM, Dana Whitlow wrote: > > > > I've long understood that ionospheric delays and variations thereof lead > to > > *position* > > uncertainties in GPS navigatio

Re: [time-nuts] U-blox teaser

I've long understood that ionospheric delays and variations thereof lead to *position* uncertainties in GPS navigation receivers, to the tune of perhaps 10m (2DRMS IIRC)., and that these are said to constitute the single largest GPS error source. Q1: Would this not imply timing errors of

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

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

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] 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

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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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] 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

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] 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] 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] 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] 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] 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] 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] 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] 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

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