Re: [time-nuts] Spectracom 8140T Line Tap Schematic

Julien wrote: I'm somewhat tempted to take the schematic and see if I can fit it in the comparatively tiny Pomona boxes Before getting too excited about the various 8140 module designs, it may be worth reflecting that the performance of the 8140 system is mediocre at best from a time-nuts

Re: [time-nuts] Spectracom 8140T Line Tap Schematic

Nigel wrote: with far too many assorted internal photos plus details of said interesting discovery, with extra brownie points to anyone who might already be thinking foam and cardboard sandwiches:-) Oh, my, that brings back memories! That method of "encapsulation" was used by a number of

Re: [time-nuts] 4046 replacement

donald wrote: Question : In the 74HCT9046BCN - does a high on the inhibit line Knobble the P/F detectors as well as the VCO? I've never had occasion to use the INH pin. The 2009 NXP datasheet says it shuts down the whole circuit: "The inhibit function differs. For the 74HCT4046A a

Re: [time-nuts] WWVB: measuring local 60 KHz noise

Hal wrote: I assume the problem is noise. Is there any simple way to measure the noise around 60 KHz? How about not so simple? Extra credit for a way that others nuts can reproduce so we can compare the noise at my location with other locations. For any location near a city, the noise

Re: [time-nuts] 4046 replacement

Magnus wrote: If you use it without care and knowledge, beware. That goes for any tool we apply Indeed! The Cardinal Rule of design! (So often unfollowed) "An engineer is someone who can figure out what questions need to be asked, figure out how to answer them, and tell when they are

Re: [time-nuts] 4046 replacement

Alexander wrote: but as I wrote a while ego ADI has a bit different chip which is free of dead zone and much faster Hell, there are literally hundreds of PLL chips, lots of them better at various things than the 4046. I did not suggest that the 4046/7046/9046 is the best PLL for any

Re: [time-nuts] 4046 replacement

See below for further information on working with the 4046/7046/9046 PLL families, including must-have design tools for anyone designing with these devices. I wrote: The "flaw" in the 4046 is a dead zone around zero error in Phase Comparator 2 (the PC one generally uses). Magnus responded:

Re: [time-nuts] WWVB: measuring local 60 KHz noise

Alberto wrote: If you have a sound card capable of sampling at 192 kS/s, you don't need an SDR to receive a signal at 60 kHz... just connect the output of an active antenna, like e.g. the mini-whip, directly to the Line-In of the sound card * * * I used this method in the past to

Re: [time-nuts] 4046 replacement

Rick wrote: The book is incorrect. A patent issued in 1976 (US4023116A) covering the Fairchild 11C44 developed by Eric Breeze predates the EDN article by several years. I still remember the big splash the 11C44 made when it was introduced in 1976. The Fairchild ECL data book had a famous

Re: [time-nuts] 4046 replacement

donald wrote: HEF4046BCN`s, but have recently read that this CMOS IC has a design flaw. What would be a better chip to retrofit? As Bill said, the HCT9046 is the improved version of the 4046. The "flaw" in the 4046 is a dead zone around zero error in Phase Comparator 2 (the PC one generally

Re: [time-nuts] Wavecrest DTS2075

John wrote: It's more a burst-mode and averaging analyzer like the HP 5371/5372. But it can do sustained time interval measurements if you mess around enough with the settings. And the resolution is down in the very low picoseconds. But it's big, awkwardly shaped, and has a jet turbine

Re: [time-nuts] ULN regulator with more current capability than LT3042?

Tom wrote: Run two in parallel for twice the current and less noise? This is actually a better solution than using an LT3045, for two reasons. First, as Tom noted, by paralleling two devices, the noise is reduced by sqrt 2 = ~1.4: "Designed as a precision current reference followed by a

Re: [time-nuts] How to properly simulate PLLs?

Attila wrote: my first thought was to use spice to simulate the loop. But I am not sure how the non-linear effects of the PLL, the divider chains etc affect the whole system and whether a spice simulation (which would use a linear approximation of a few components) would model the system

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Poul-Henning wrote: I fully agree, and if it were me, I would absolutely use the best capacitor I could find at a non-insane price. But that was exacly my point: The only thing you (might!) get by spending an *insane* amount of money on that capacitor is PTFE and its better dielectric

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Poul-Henning wrote: The input signal to the integrator is continuous and jump-free and the relevant time constant is sub-second. Dielectric absorption doesn't matter when there are no voltage jumps. That is a very common misconception, probably fostered by the usual test methodology for DA.

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Interesting. I'm inclined to say I stand corrected, BUT: (i) as Mark noted, the datasheet link points to the datasheet for Vishay FC Series HF thin-film resistors [which are really excellent low-reactance T/F resistors, if you need any]; (ii) I cannot find any reference to PC caps on the

Re: [time-nuts] Replacement A9 boards for the HP 5065A

Returning to the topic of what op-amp to use: Bert asked if the LT1793 is a good choice. I suggested the LT1012 as superior in the specific parameters that will provide best performance in the HP circuit (https://www.febo.com/pipermail/time-nuts/2018-February/108964.html). Attila suggested

Re: [time-nuts] Replacement A9 boards for the HP 5065A

The key properties relevant to long-TC integrator capacitors are insulation resistance (leakage) and dielectric absorption (DA). (One response on this thread opined that DA is not important in this circuit, but that is not correct. DA is most definitely a factor in long-TC integrators,

Re: [time-nuts] HP 5065A super

Ais the LT1793 the best choice the time constant is 0.05 seconds with a 10 K resistor and 5 uF Capacitor Bshould we add resistors and decoupling on the + - 15 volt op amp supplies CGold plating the edge connecter, does any one know a reasonable source, or is doing it at home an

Re: [time-nuts] AM vs PM noise of signal sources

Bill wrote: A switching regulator without the steep (and noisy) transients of today's switchers. Well, don't get too giddy about how quiet the scheme is . HP warned that if you use the same 12v (nominal) power supply for the oven control and crystal oscillator circuits, you need to add

Re: [time-nuts] AM vs PM noise of signal sources

Bill wrote: What does the unijunction 2N2646 do in the oven controller? For the following discussion, you need to refer to the *corrected* schematic I mentioned in my last post. If you are looking at the HP schematic, you will wonder how the hell it works (and it wouldn't, if HP actually

Re: [time-nuts] AM vs PM noise of signal sources

Don wrote: I`m looking at the circuit of an HP10544 oscillator - can anybody confirm, please, if the HP transistor types 53-20, and 54-215 have commercial equivalents? 54-215 (full HP part number 1854-0215) is the ubiquitous 2N3904. 53-20 (full HP part number 1853-0020) is 2N3702. 2N4403 is

Re: [time-nuts] TAPR "PulsePuppy" Pot Selection

John wrote: I didn't really notice much backlash, though when setting oscillators I try to approach (slowly) from one direction until it's "good enough" and then stop, to avoid that problem. The hot tip is not to just "sneak[] up on the sweet spot and then walk[] away," as Dana put it.

Re: [time-nuts] External cooling fans - source

David wrote: For what it is worth, my 5370B run very hot, which forced me to check my mains voltage* * * it was consistently high.* * * I managed to get the supply company to reduce the voltage by 5%. Eliminating that small amount of extra dissipation won't get you anywhere

Re: [time-nuts] accurate 60 hz reference chips/ckts

Jeremy wrote: I'm surprised Vlad is seeing as much as six seconds differential but maybe I don't understand the experiment. I've done measurements of the line frequency here in California and never seen much variation. When was the earliest time (year) you started looking seriously at the

Re: [time-nuts] HP5065 - Some OP-Amp, FB and Teflon ...

Forrest wrote: I looked up the schematic for the 5065A, couldn't find the OPA111 anywhere The LT1793 in particular is marketed as a drop-in replacement for the OPA111, although some of the specs seem worse. TI points people toward the OPA124 and OPA627 parts. In particular the OPA627 is

Re: [time-nuts] HP5065A C-field mods and optical unit mods

Luciano wrote: what you refer is the resistance relation referred to the LM299 source around 14VDc but you have to consider the tuning range of the pot, in the original HP5065A is 2E10-9. Of course, it depends on the setting value of the variable resistance, but you have to

Re: [time-nuts] HP5065A C-field mods and optical unit mods

Luciano wrote: about the C field ten turn pot you write is a low TC pot. Normally a good Vishay pot is 20 PPM/C, This is in conflict with the 1PPM resistors ad voltage reference. In the schematic Corby posted, the potentiometer (used as a variable resistor) makes up a very small part of

Re: [time-nuts] Input filter for data logger

Bruce wrote: Oops I meat to say: Thats a MOSFET variant of a fairly standard JFET-BJT feedback amplifier. I think you were right the first time. Vlad said in his first post that the input device is a 2N5485 (JFET). I'm not sure why Vlad designed the input squarer that way. If the

Re: [time-nuts] Continously drifting HP 10811...

Ulf wrote: the oscillators exhibit a monotonus EFC voltage drift towards 0 volts. About + 1 mV in 3 minutes. * * * Test time has been 3 Days, and I beleive thata 10811 should have been able to reach thermal equilibrium during this time. There is much more than thermal equilibrium

Re: [time-nuts] Weird GPSDO behavior

Skip wrote: I have a NTGS50AA GPSDO (close cousin to the NTBW50AA and Thunderbolt) with the OCXO removed and a SRS PRS-10 rubidium oscillator in its place. Once per day (about 8am) something disturbs the system. So, the GPSDO spends much of its time recovering and never gives me anywhere near

Re: [time-nuts] HP-103AR frequency beyond adjustment

Jeremy wrote: The only thing I've not adjusted is the oven temperature. I know there's been discussion of this subject here in the past but my searches come up empty—I must be using the wrong keywords. The 103AR is just a toy for me so no harm is done if the frequency can't be raised to 1 MHz

Re: [time-nuts] HP-531xx calibrator nearing completion

Chris wrote: Mark Sims wrote: It takes a 10 MHz input, feeds it through a sine-to square converter (using a biased CMOS gate) Could you send me a snip of what that looks like? Depending on your application and its tolerance for jitter/PN, you may want to use a fast analog comparator to

Re: [time-nuts] GPS Antenna Feed Line Decision

Mike wrote: I tried to see if there was any difference in the signal quality reported by Motorola UT+ and U-Blox Neo 6M (not timing grade but has a good 1PPS) over 30m of 2 different cable types. I only had RG58(75 Ohm) and RG174(50 Ohm). RG58 is 50 ohm. RG59 is the "equivalent" 75-ohm

Re: [time-nuts] GPS Antenna Feed Line Decision

Attila wrote: The supplies for LNAs are usually quite benign given two constraints: * * * 1) Low frequency (0Hz to bandwidth of signal) noise is low * * * But 1) is a bit harder as it also includes 1/f noise, temperature, (upstream) supply and load effects. The LT3042 is better

Re: [time-nuts] Isolated 1PPS-input for distribution-amp?

Anders wrote: I'm looking for a solution for galvanic isolation of a 1PPS signal-input to a distribution amplifier. * * * Does anyone have experience with a circuit with good rise-time and low jitter? Sometimes the simplest solutions can be best. In this case, capacitive coupling

Re: [time-nuts] Machining some aluminum help!

Joseph wrote: For _forming_, one needs something very viscous, something that lubricates at very high pressures, at the yield strength of the material being formed. I've had excellent results with STP oil treatment, by itself or with added Tungsten disulfide. I frequently tap under power at

Re: [time-nuts] Thunderbolt question

Arthur wrote: I’d say it would be an MMIC amp similar to this device [Avago MGA-87563] If a chip similar to the Avago part Arthur referenced is what is installed, which seems plausible, the 0.749v on the RF input (Pin 3) is a fault and is caused by an external source of voltage (3.417v)

Re: [time-nuts] OCXO inside the FEI AN/URQ-23

Bert wrote: Has any one run tests of the OCXO inside the AN/URQ-23. I've played with several of the pulled oscillators. They're nothing special -- xDEV at most frequencies for the ones I've seen is around 5-20x worse than an HP 10811. I tested them after they had been running for 2-3

Re: [time-nuts] 5370B Input Board Repair

Could it be that someone thought adhesive would be less prone to cracking from stress than solder? More likely, it was a process decision. They most likely wave-soldered the board, but the switch side has gold-plated switch contacts, so they couldn't wave-solder that side. So, to put a few

Re: [time-nuts] DAC performance

Attila wrote: Charles Steinmetz <csteinm...@yandex.com> wrote: how about the LTC1650? * * * [it] is nearly 100x (40dB) quieter (30nV/sqrtHz vs. 280) [than the 1650] I was about to ask the same question :-) Note: I divided 280 by 30 and got "nearly 100x".

Re: [time-nuts] DAC performance [WAS: Papers on timing for lunar laser ranging]

Bert wrote: We limited to affordable and solderable. The LTC1655 was the clear winner because of linearity and temperature * * * Five years later I know no better alternative Well, to name just the first one that comes to mind, how about the LTC1650? Like the 1655, it is

Re: [time-nuts] J06 HP-59992A time interval calibrator for HP-531xx counters

Mark wrote: I need a simple and cheap circuit to level shift the TTL signal to +/- 0.50V It probably needs clean, stable, fast edges and able to drive a 50 ohm load See attached. The resistor values shown assume that the source is a 0-5v rectangular signal able to source +/- 10mA with

Re: [time-nuts] Power connectors continued

Someone previously mentioned "aviation" style connectors (which many will recognize as mobile microphone connectors) (see graphic below). I switched to these for power and other connections long ago, and have been extremely happy with them. One nice thing about them (IMO) is that all chassis

Re: [time-nuts] SR620/PM66xx/CNT-90 input stages

Bruce wrote: If the source impendance at dc is 10k at dc a bias current of a few microamp produces a dc offset of tens of millivolts which may be an issue if the signal amplitude is low and has a low slew rate. Jeez, Bruce, it was nothing but a thought experiment to illustrate why an

Re: [time-nuts] SR620/PM66xx/CNT-90 input stages

Attila wrote: Now, if the downstream circuit would be low impedance, I could understand that, but the sink is a comparator with a high impedance input (only a few µA input current). I am sure the engineers had a good reason to add those amplifiers, but I cannot guess why. Would someone be so

Re: [time-nuts] GPS splitter

Clay wrote: If sharing an active GPS antenna, do you have to DC block all but one receiver port to prevent multiple receivers trying to supply current to the antenna? Yes. Note that you may need to put DC loads on the other receivers to fool them into thinking they have an antenna attached

Re: [time-nuts] GPS discipline oscillator vs phase lock

life-sp...@yahoo.com wrote: Perhaps I could implement an ISM band radio link for the purpose of locking the two oscillators. Of course that wouldn't reach a couple miles either. There appears to be some amount of talking past each other going on here. First, I think you may have a

Re: [time-nuts] Powering up a long inactive 5061A

Hugh wrote: Would welcome feedback on sensible/cautious first steps with the unit - initial need, if possible, is a "simple" go/no go/does it power on ? You may find the information on this page helpful:

Re: [time-nuts] backfill

Poul-Henning wrote: Next down the line is hydrogen, which comes with a shitload of issues. No argument there. But other methods all have their own shitloads -- it just depends on which shitload the designers dislike the least. you will find little love for hydrogen cooling [today] In

Re: [time-nuts] backfill

Bob wrote: In this case hydrogen + oxygen (like from oxidized metal) goes to H20. You very much do not want water running around inside your crystal holder… Helium is inert. The insides of mains alternators are almost entirely metal -- tons and tons of copper tubing, and the casings and

Re: [time-nuts] backfill

Bob wrote: You really want to use Helium. Hydrogen is a bit reactive. I don't think it's a problem. The alternators on mains powerplants are filled with Hydrogen under fair pressure, and the internal materials and conditions are not that different from a crystal oscillator inside an oven.

Re: [time-nuts] uC ADC resolution (was: Poor man's oven)

Chris wrote: Assume me goal is to regulate temperer of an aluminum block to within 0.1C, how good must my ADC be? Is an effective 6-bits good enough? * * *If I scale the input to the ADC such that it os 1.0C from 0 to 63 counts then each cunt is 1/64 C which is about 6 times better

Re: [time-nuts] Poor man's oven

Poul-Henning wrote: what I'm interested in is at which exterior temperature OCXO ovens work best ? Jim replied: Here's my guess... 1) you want minimal gradients across the device for a variety of reasons 2) therefore you want least amount of heat from the heater 3) therefore somewhat below

Re: [time-nuts] Poor man's oven

Chris wrote: Today all you need is a reliable way to measure the error between the crystals' current temperature and the set point. That's all that's ever been needed. But it is devilishly difficult to measure the actual quartz temperature, or even to find a good proxy that is easier to

Re: [time-nuts] LPFRS phase ripple?

Matthias wrote: one shows quite some phase ripple (appx. 1 ns RMS with a frequency around 0.007 Hz) which spoils ADEV in the 60 - 200s range, very similiar to the typical GPSDO bump. My first guess would be a problem in the control loop locking the VCXO to the Rb Good guess. The most

Re: [time-nuts] TAPR TICC boxed (input protection)

David wrote: If the 10pA specification is guaranteed by design, then wouldn't they have to be testing the 1pA "A" parts? That assumes the parts are produced by exactly the same process, which is very often not a safe assumption. One of them may undergo extra process steps, for example, or

Re: [time-nuts] TAPR TICC boxed (input protection)

David wrote: I ended up qualifying 2N3904s based on manufacturer and lot and I think we ended up using ones from Motorola. I wish detailed process information like National had was available from every manufacturer. It is, if you ask the process engineers for it. (From the Big Boys, that

Re: [time-nuts] TAPR TICC boxed (input protection)

David wrote: I ended up qualifying 2N3904s based on manufacturer and lot and I think we ended up using ones from Motorola. I wish detailed process information like National had was available from every manufacturer. It is, if you ask the process engineers for it. (From the Big Boys, that

Re: [time-nuts] HP 100D FS [WAS: HP 105D FS]

Perry wrote: The HP oscillator is a 100D Low Frequency Standard.. Sorry for the brain fart. For a bit more information on the 100D (and 100C), see the October, 1949 Hewlett Packard Journal: Note the accuracy and stability specs:

Re: [time-nuts] TAPR TICC boxed (input protection)

David wrote: I mentioned this in connection with some manufacturers using gold doping in transistors which would not normally be expected to have gold doping. So you end up with a bunch of lessor named 2N3904s which meet the 2N3904 specifications but are useless if you were looking for low

Re: [time-nuts] TAPR TICC boxed (input protection)

David wrote: So gold doping does work with PNP devices. Previously when I brought it up, I was told gold doping only applied to NPN devices leading to my confusion. Since I posted, I dug through my books and found a few more references on point: A couple of textbooks say commercial PNP

Re: [time-nuts] The ultraAtomic clock for home

Jim wrote: Charles wrote: [blob over wire bond construction] is also extremely unreliable, particularly WRT environmental effects such as temperature changes, humidity, and atmospheric pollutants. In my view, it is unsuitable for use in anything but dirt cheap, purely disposable devices like

Re: [time-nuts] The ultraAtomic clock for home

Bob wrote: The epoxy over wire bond construction approach is low cost, and not very experimenter friendly. It is also extremely unreliable, particularly WRT environmental effects such as temperature changes, humidity, and atmospheric pollutants. In my view, it is unsuitable for use in

Re: [time-nuts] TAPR TICC boxed (input protection)

David wrote: what doping is used for PNP RF transistors and saturated switches if it is not gold? Does it also increase leakage? I replied: Gold doping doesn't affect the speed of BJTs in the active region very much -- its purpose is to reduce minority carrier lifetime and, thereby, to

Re: [time-nuts] TAPR TICC boxed (input protection)

David wrote: I know one thing to watch out for if you are looking for low leakage is gold doping Anything that increases carrier mobility increases leakage current (all else equal -- i.e., for each particular device geometry). This accounts for the much higher leakage of Schottky and

Re: [time-nuts] TAPR TICC boxed (input protection)

David wrote: So collector-base junctions make good low leakage high voltage diodes although they are slow I guess it depends on what one means by "slow" and "fast." The B-C junction of an MPSH10/MMBTH10 or 2N/PN/MMBT5179 switches on in <1nS and off in <2nS, which is comparable with Schottky

Re: [time-nuts] TAPR TICC boxed (input protection)

nal diodes and *much* lower cost). Best regards, Charles On 3/31/2017 9:39 PM, Alex Pummer wrote: FJH1100 Ultra Low Leakage Diode Alex On 3/31/2017 6:00 PM, Charles Steinmetz wrote: Mark wrote: I thought about using the clamp diodes as protection but was a bit worried about power supply noi

Re: [time-nuts] TAPR TICC boxed

Mark wrote: I thought about using the clamp diodes as protection but was a bit worried about power supply noise leaking through the diodes and adding some jitter to the input signals... It is a definite worry even with a low-noise, 50 ohm input, and a potential disaster with a 1Mohm input.

Re: [time-nuts] What interrupts aging?

John wrote: We know of OCXO that have been continuously running for years and have exceptional aging, supposedly as a result. What does it take to interrupt that? A momentary loss of power? The oven cooling down? Some long period of off-time? Or, once the oscillator has baked in will it

Re: [time-nuts] Distribution amplifier (again!) - now mostly ok but has gain peaking

Ruslan wrote: Have you looked at the design of the HP/Agilent/Keysight E1750A (sine timebase of various standard frequencies)...? According to the specifications on the 5087A/E1750A/E1752A spec sheet, the 1750A is no better WRT phase noise than the 5087A, and the 5087A is distinctly ...

Re: [time-nuts] Distribution amplifier (again!) - now mostly ok but has gain peaking

Scott wrote: Parasitic capacitance on the inverting terminal from routing and the input capacitance of the opamp itself, adds another pole to your opamp's loopgain, burning phase margin. A small compensation cap across the top leg of your feedback divider, would boost your phase margin.

Re: [time-nuts] 10MHz to 25MHz

Bob wrote: That gets me to a quick intro to the episode and a link to watch the whole thing. The watch the whole thing link sends me off to another episode entirely Huh. Worked fine for me, originally and just now. Charles ___ time-nuts mailing

Re: [time-nuts] 10MHz to 25MHz

jimlux wrote: I forgot to watch (actually, I knew it was today, but I thought it would be on this afternoon, not at 7AM).. (and, I'll get a call from management on Monday.. uh, Jim, about that interview) LOL Try this:

Re: [time-nuts] 10MHz to 25MHz

Bob wrote: is a $250,000 OCXO that is 1 cubic meter in size appropriate for your application? The answer to that one is universally - NO Well, it'll be a lot cheaper when it shows up on ebay. The shipping might be a killer, though. ;-) Best regards, Charles

Re: [time-nuts] 10MHz to 25MHz

Chris wrote: I have always wondered why we build our "standard" with such a low frequency. Why not a 100MHz GPSDO? Why 10MHz Quartz crystals work better at lower frequencies, predominantly because they have higher Q. 10MHz was chosen because it is low enough for excellent performance

Re: [time-nuts] Thunderbolt Harmonics

Is what your seeing a harmonic (2nd? 3rd?) or a spur i.e what frequency is the "harmonic" ? The OP attached a spectrum analyzer screen shot to his initial post -- go back and have a look. It shows the harmonic series from 1 to 7, with H6 close to the noise level. Loudest harmonic is H2 at

Re: [time-nuts] Thunderbolt Harmonics

I suppose I should have said that Trimble specifies the Tbolt with harmonics -40dBc max, according to the User Guide v.5.0 (2003). Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] Thunderbolt Harmonics

Rhys wrote: I was looking at the output of my Trimble Thunderbolt GPSDO and was rather surprised to see really "loud" harmonics in there. ~ 60dB down from the 10Mhz signal. Welcome to the world of RF. Loudest harmonic at ~ -60dBc (dB with respect to carrier) is actually pretty good for a

Re: [time-nuts] Low CostTemperature sensor

Tom wrote: That article has a major error. Anyone know what it is? Well, the author says the reverse current of a diode is "directly" proportional to temperature. This could suggest that he means the relationship is linear (the relationship is actually exponential with absolute

Re: [time-nuts] Cure for hot 5370B counters

Bob wrote: If you can touch the heat sink for 2 seconds, you're made of sterner stuff than I am! They run very hot. As I've said before, get a little desk fan (see attached photo). Position it behind the counter, blowing straight into the heatsink from 2-3 inches away. The ones I have

Re: [time-nuts] HP Z3801 RB fun

paul wrote: The 10811 is far more difficult to pin down as several articles from TVB and others say the 10811 actually has a wider control range then the standard. Something like 10 Hz over 10V. Traditional is 1 Hz over 10 V. But as I say seems to be different answers depending on what you

Re: [time-nuts] Why is holdover LED on HP 58503A not lit

David wrote: This does appear now to be working - see below. I'm not exactly sure what was the secret to getting this to work, but the above procedure seemed ok. Time. It is not at all unusual for a 58503A that has no almanac (or an out-of-date almanac) to take several days to achieve

Re: [time-nuts] Lady Heather for homebrew GPSDO

Mark wrote: The Z3801A does have a request for getting/setting the DAC value as a absolute (hex) number. Neither format tells you what you really want to know... the actual DAC voltage. If the hex number isn't the DAC output voltage, what is it? The code being fed to the DAC? Just

Re: [time-nuts] Temperature weirdness with Thunderbolt & Lady Heather 5

Tom wrote: There's something very odd going on here, either with Pete's TBolt, and/or with Mark's Heather v5. 2) It also shows some truly erratic behavior the last day and a half, with multiple, massive, sudden temperature drops going down several degrees. I've never seen this. I think

Re: [time-nuts] Austron 2010B Manual.

Bob wrote: I found my Austron manuals CD last night while cleaning up the ham shack. I'll send a copy tonight. Bob, perhaps you could also upload the 2010B manual (and any other Austron manuals you have that are not currently in circulation) to Didier's site:

Re: [time-nuts] Totally unrelated, but..

Ed wrote: It would be helpful to give some specific info about the circuit and regulators used for these experiments, such as operating voltage, load current, and regulator type. I concur. It would also be helpful to have more detail about the phenomenon you are observing (see below).

Re: [time-nuts] HP Z3801A Software

Any other software out there for the "Z-Box" besides SatStat (clock works, nothing else) or GPSCon (too pricey for this Olde Yankee) ? I'm surprised nobody has mentioned the late Ulrich Bangert's free software, "Z38xx". Still available on Ulrich's web site:

Re: [time-nuts] Excel logarithmic function

Rick wrote: The one thing I can say is that it is good to keep the crystal ovenized at all times. Even a momentary oven outage tends to reboot aging. That has been my observation, as well. Same with mechanical shock and with interruptions of oscillation (even if the oven remains

Re: [time-nuts] Inside of FT1200-100

Christopher wrote: And of course it is a discontinued part. Taking suggestions for a replacement. COG(NP0)? I applaud your ingenuity and resourcefulness in tackling this project! I just love seeing nice old tech restored to service. Your three basic choices are mica, C0G/NP0 ceramic,

Re: [time-nuts] How can I measure GPS Antenna quality?

Mark wrote: The tricky bit is interpolating signal levels between logged points (there is a display options for showing the raw signal level data). Heather interpolates between adjacent azimuth points at each elevation angle. I always wondered about the "filled in" (interpolated) plot.

Re: [time-nuts] 53132 replacement fan

Adrian wrote: This one's pretty quiet. But the airflow is a bit lower. This one moves a little more air than the original (7.7 cfm) and is somewhat quieter than the original (by 2dB): If you want to improve cooling, this one moves much more air

Re: [time-nuts] 53132 replacement fan

Tom wrote: EFB0412MD Airflow 7.17 CFM 6300 RPM Noise 24 dBA FBK04F12U Same exact form factor. Air Flow 9.2 CFM 9500 RPM Noise 42 dB(A) Note the 18dB greater noise (that's a HUGE difference). Even with bad bearings in the original fan, it is probably considerably quieter (by 10dB or more)

Re: [time-nuts] Inside of FT1200-100

Christopher wrote: Despite running out the three sloted screws on the "top" around the circumference, I'm not into the inside yet. I don't have the right thin-walled socket to remove the nuts at the opposite end. It looks like a standard 5/32" nut driver will work fine.

Re: [time-nuts] quartz drift rates, linear or log

Attila wrote: Yes, depending on the data you show, it is not clear whether one should do a linear or a logarithmic fit. When the purpose is correcting a GPSDO local oscillator during holdover, it depends on how long one expects to trust the corrected frequency. Practical realities make it

Re: [time-nuts] Nutty time-nuttery with WWVB

Alex wrote: And how about that many, many "radiator" which are moving up and down with their carriers and don't give a damn about FCC Part 15 and radiating radiating day and night with substantial power, I meant that FFC approved and not approved switching mode power supplies SMPSs are

Re: [time-nuts] Nutty time-nuttery with WWVB

Peter wrote: Could I implement my own personal WWVB transmitter that would be powerful enough to be picked up by the clocks in my house? * * * Has anyone tried this? Some on the list have, and I'm sure they will provide the details. Others have mentioned the potential problems with

Re: [time-nuts] Subject: Re: I love the smell of tantalum in the morning

Jeremy wrote: Amazon indicates the different lenses simply snap in and out. Any idea how easy/practical this is? It it better to have two completely different visors each holding different magnification lenses? Quite easy -- the lens plates are held onto the front of the visor by two plastic

Re: [time-nuts] eLORAN on the air for 30 days

Magnus wrote: You describe why I say it's clearly not dead yet. No, as I said, it is well and truly dead -- all that remains is to sign the death certificate. The decisionmakers have made their final decisions, and further "tests," demonstrations, and whining by proponents is not going

Re: [time-nuts] eLORAN on the air for 30 days

Magnus wrote: It's interesting in that it's clearly not dead yet, rather the opposite. No, it's well and truly dead. Of the people I know on the political and regulatory sides, not one thinks there is even the slightest possibility of a revival. The only chance appears to be if, before

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