Re: [time-nuts] Lucent RFTG-u REF0-REF1 cable

Hi At some very basic level, the GPSDO needs to decide when to go into or come out of holdover. That decision often involves initial setup of the GPS module and subsequent monitoring of the module. The risk in swapping modules is always tripping over an obscure IF statement somewhere that does

Re: [time-nuts] Lucent RFTG-u REF0-REF1 cable

gt;>> without the cable. I thought about splitting the two and using this >>> other GPS unit I have (it was one of the TAPR GPS Kits) to send the >>> other one the 1pps. You’re saying all you need is a plug? I would >>> need two functioning units. >>> >&

Re: [time-nuts] Lucent RFTG-u REF0-REF1 cable

uld need two functioning units. > > Regards, > > Jerry > > > Jerry Hancock > je...@hanler.com > (415) 215-3779 > >> On Nov 14, 2017, at 8:13 AM, Bob Camp <kb...@n1k.org> wrote: >> >> Hi >> >> If you are going to get out the soldering i

Re: [time-nuts] Lucent RFTG-u REF0-REF1 cable

Hi If you are going to get out the soldering iron, why simply make up a plug to run the GPS unit stand alone? Keep the second unit powered down as a set of spare parts….. Yes, it does depend a bit on what you are doing with them …. Bob > On Nov 13, 2017, at 11:50 PM, Jerry Hancock

Re: [time-nuts] Wenzel VHF PLO Oscillators Off Frequency

Hi If the device pulls > 50 ppm at 80 MHz, it’s a wide range VCXO with a heater on it :) That is way more than you can pull a proper (low ADEV) OCXO. Bob > On Nov 13, 2017, at 5:04 AM, Mark Goldberg wrote: > > On Sun, Nov 12, 2017 at 7:02 PM, Mark Goldberg

Re: [time-nuts] GPS III

Hi There are papers from ION and other places detailing testing on the new(er) clocks. They do have quite good ADEV performance. If they start showing up on eBay, expect a bidding war …. The most useful thing for an L1 user is getting the added bits into the datastream for the epoch. That

Re: [time-nuts] Wenzel VHF PLO Oscillators Off Frequency

; 500-14273 wants a 13 MHz input, 500-25010 uses 24.576 MHz, and 500-25009 >> uses 19.2 MHz. So that's probably the issue, if two of them seem to be >> failing the same way. >> >> -- john, KE5FX >> Miles Design LLC >> >> >>> -Original

Re: [time-nuts] Wenzel VHF PLO Oscillators Off Frequency

t; and "15V on the label. Maybe > someone swapped the labels. I did try lowering the supply voltage. It got > to 80 MHz at about 11V and still did not lock to the reference. This > oscillator is specified at 1e-6/year aging. That is way less than it is off > now. > > Ma

Re: [time-nuts] Wenzel VHF PLO Oscillators Off Frequency

et a good unit > and them getting a sale. > > Mark > > > On Sun, Nov 12, 2017 at 9:22 AM, Bob Camp <kb...@n1k.org> wrote: > >> Hi >> >> As a guess - the oven circuit has stopped working. Next step >> would be to tear it open and trace out the sc

Re: [time-nuts] Oscillators and Ovens

Hi I would say there are *very* few companies out there that will sell you high grade precision OCXO crystals in single piece quantities. I think you would get one much quicker and cheaper by pulling it out of an eBay OCXO. You can do good far removed phase noise with a lot of crystals.

Re: [time-nuts] Wenzel VHF PLO Oscillators Off Frequency

Hi As a guess - the oven circuit has stopped working. Next step would be to tear it open and trace out the schematic. After that make reasonable guesses for any parts that are poorly labeled. Much of what shows up on eBay has been through the ringer in China. A high percentage the OCXO's I get

Re: [time-nuts] Favorite counters (current production)?

that goes into the > longlivety of a product, such as access to components, but also strategy of > companies. > > The CNT-90/91 an 53230 both have graphical presentation, which is very > beneficial. The SR-620 still have better performance even being older than > everything else. >

Re: [time-nuts] Favorite counters (current production)?

Hi There is no perfect answer. I’d go with the 53230 simply because it *might* be supported the longest. Bob > On Nov 10, 2017, at 11:17 AM, Scott Newell wrote: > > What current production freq counters do people like for general time-nuttery > these days?

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

Hi One interesting thing to look at on modern OCXO’s: Part of the factory alignment *probably* was intended to set the unit at the center of the EFC range. Back in the days of people selecting caps or selecting resistors, that could be a pretty coarse kind of thing. At some point computers got

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

Hi One of the weak points of a normal 10811 is that it is not hermetically sealed. Left in storage for years, they “soak up” humidity. In some cases it can take a fairly long time (weeks, months) for them to fully dry out. Until they have been run for at least a week, don’t get excited about

Re: [time-nuts] ublox NEO-M8T improved by insulated chamber?

Hi If you go back into the NIST evaluations of various receiver modules ….. they don’t always work best with the correct coordinates. Some have guessed there are residual math errors in the devices. Others suggest the “radio side” may be at fault. Indeed varying susceptibility to multipath

Re: [time-nuts] TAPR TICC boxed

Hi You could simply immerse all the cables in a swimming pool full of mercury … :) (bonus points for a link to the prior discussion of that topic ..). Bob > On Apr 2, 2017, at 11:05 PM, Bruce Griffiths > wrote: > > For even more fun you could try to detect the

Re: [time-nuts] GPS first LO need to be locked?

Hi > On Apr 1, 2017, at 11:18 AM, paul swed wrote: > > Thanks everyone but I am working on an austron 2201a so all the discussions > on modern methods won't help. Whats is interesting is indeed the 2201 down > converts to 80KHz and the does sample in an IQ fashion. Its all

Re: [time-nuts] TAPR TICC boxed

Hi The whole delay difference thing does get into a “do you care?” sort of category. The testing process you are doing may well calibrate out (or ignore) an offset of this nature. This is quite true in a number of TimeNut sort of tests. Bob > On Apr 1, 2017, at 4:02 AM, Bruce Griffiths

Re: [time-nuts] more of a time distribution question

Hi The 8736 is a very nice part. I think some sort of group buy would be a good idea. Bob Sent from my iPhone > On Mar 31, 2017, at 12:14 PM, Bob Darlington wrote: > > I guess it's time for me to finish up that NTP cape for the BeagleBone. > I'm using a Furuno

Re: [time-nuts] GPS first LO need to be locked?

Hi There is a limited tracking range for Doppler. You would need to stay inside that. Bob Sent from my iPhone > On Mar 30, 2017, at 9:46 AM, paul swed wrote: > > I am curious if the first local oscillator on a GPS receiver must actually > be locked or coherent to the

Re: [time-nuts] Sub 20 ps time detection

Hi One of the nasty issues doing something like this is the voltage tolerances. If you are after 0.02 ns on a 2 ns edge, that is at the 1% level. If you want a 10X margin to take the voltages out of the picture, you are now at the 0.1% level. If you have 3.3V logic 0.1% is 3.3 mv. That is

Re: [time-nuts] Time Dilation tinkering

Hi Back before GPS and similar systems, hauling Cs standards on commercial aircraft was a bit more common than it is today. One of the critical tricks of the trade was knowing where each power outlet was on a specific plane and how close it was to this or that seat. The next trick was knowing

Re: [time-nuts] Time Dilation tinkering

Hi In this case, the vacuum might work against you. You change the pressure outside the package and you get a flex. Flex translates to dimensional changes. That gives you a frequency shift. People make absolute pressure sensors this way :) Rb’s are by no means the only frequency standard

Re: [time-nuts] PLL Digital Loop Filter

Hi Some quick hints: 1) You need a way to digitize the phase input with adequate resolution. If you have a 1 second period and want 1 ns, you need a way to digitize at a 1:1,000,000,000 sort of level. That’s in the 30 bit range so a simple ADC isn’t going to do it alone. 2) You need a way to

Re: [time-nuts] PLL Digital Loop Filter

Hi Slipped a factor of 1,000 on the DAC … sorry about that … Bob > On Mar 21, 2017, at 7:25 PM, James Peroulas wrote: > > Thanks for the hints and references everyone. I'll dig in and possibly come > back with some more questions. > > BR, > James >

Re: [time-nuts] Time Dilation tinkering

Hi Ummm … e …. it’s a gas cell standard. I’d bet there is a pressure effect. Bob > On Mar 21, 2017, at 7:01 PM, Scott McGrath wrote: > > Noted > > However CSAC not subject to barometric effects as Rb units are > > Content by Scott > Typos by Siri > >> On Mar 21,

Re: [time-nuts] Four hour cycle in GPS NMEA jitter

HI > On Mar 21, 2017, at 4:52 PM, Trent Piepho wrote: > > Thanks to all who responded. Yes, I know PPS is the way get a more > accurate timestamps. That is the plan, but it takes more time to write > FPGA programs. The surprise is not that there is considerable

Re: [time-nuts] TS2100: Which OCXO's work?

Hi > On Mar 21, 2017, at 1:37 AM, Bruce Lane wrote: > > Fellow time-tickers, > > My thanks to Greg for getting back to me (and apologies for the spam > filter bounce) but, apparently, MTI 240 OCXO's have become unobtanium. > > With this in mind: What

Re: [time-nuts] Time Dilation tinkering

H > On Mar 21, 2017, at 4:58 AM, Tom Van Baak wrote: > > Hi Hugh, > >> If I do the math correctly that's about 14ns difference per 24h the >> clocks are separated by that altitude. [1] > > That's correct. For your 1500m elevation gain, the gravitational redshift, > the

Re: [time-nuts] time-nuts equipment verification from scratch (was: WTB: GPSDO)

Hi > On Mar 21, 2017, at 1:07 AM, Chris Albertson > wrote: > > I built one of these using a PWM DAC also. The design was posted to this > list so I can't take credit for the idea. But we used two PWM output > pins. The PWM provides more voltage range than is

Re: [time-nuts] Four hour cycle in GPS NMEA jitter

Hi NMEA sentences are not the best thing to use for timing. If you *do* decide to use them, configure the receiver so that one and only one sentence comes out. Any time you have more than one, you run the risk of collision in the serial buffer on the part. Next thing to do is to pick the

Re: [time-nuts] WTB: GPSDO

or less shelved my plans to discipline one of my high end OCXO's > via a home brew GPSDO scheme. > > Mark Spencer > > >> On Mar 14, 2017, at 5:24 PM, Bob Camp <kb...@n1k.org> wrote: >> >> Hi >> >> >>> On Mar 14, 2017, at

Re: [time-nuts] Optical Cesium or maybe Cesium "light"!

Hi Get a bigger bag :) Bob > On Mar 18, 2017, at 4:45 PM, Wojciech Owczarek > wrote: > > I tried lifting it but it wouldn't fit in my bag :( > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to

Re: [time-nuts] Antique precision timing device without

Hi > On Mar 17, 2017, at 7:41 PM, Morris Odell wrote: > > HI all, > > Thanks to all those who responded to my post and also for the great pics of > other tuning forks. It's amazing that they were still being used for > electronic purposes as recently as the 1960s.

Re: [time-nuts] Smart Phone time display accuracy...?

Hi > On Mar 16, 2017, at 9:43 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> Under normal conditions, the Gold Codes on CDMA are synchronized to < 100 >> ns. > > Is that a full time synchronization, or something like a PPS where they can > get the ticks lined up

Re: [time-nuts] Vectron 233Y5317 OCXO data 250 Mhz

Hi Not an OCXO, but it’s a Vectron 233 https://www.vectron.com/products/xo/co-233_233h.htm The 233’s are all un-compensated XO’s Bob > On Mar 16, 2017, at 4:51 PM, Jeff AC0C wrote: > > Looking for a datasheet for this OCXO, or for the general family. > > Thanks!

Re: [time-nuts] Smart Phone time display accuracy...?

Hi Under normal conditions, the Gold Codes on CDMA are synchronized to < 100 ns. It’s only when something goes wrong that they drift out to the 10 us range. Once they get there, the transmitter needs to shut down. Unfortunately, there is no mandatory connection between the transmitter time

Re: [time-nuts] Bye-Bye Crystals

50 Hz just for the first year. Bob > On Mar 15, 2017, at 6:11 PM, Bruce Griffiths <bruce.griffi...@xtra.co.nz> > wrote: > > Bob > > He stated 0.01Hz EFC tuning range was adequate. > Gave no spec as to how close to nominal frequency is required though. > > Bruc

Re: [time-nuts] Bye-Bye Crystals

Hi > On Mar 15, 2017, at 3:55 PM, Dan Kemppainen wrote: > > Hi Bob, > > If one prototypes any crystal oscillator, and runs it on a bench. Then builds > an 'oven' of sorts and runs it on the same bench. Would you expect to see any > improvement? Sure, the XO likely

Re: [time-nuts] Bye-Bye Crystals

de, but I build a simple oscillator with a 4060 chip > placed in a double oven, and reached 10E-9 short term stability up to 10sec > tau. > Not bad, so wondering if I can get better with a more advanced design. > Gilles. > > >> Le 15 mars 2017 à 12:45, Bob Camp <kb...@n1

Re: [time-nuts] Bye-Bye Crystals

Hi Where do you plan on getting an OCXO grade crystal at an odd frequency like that? Much of the performance of a good OCXO is in the crystal. Doing a proper design on one is a lot of work. You *might* think that having a design for 5.00 MHz would give you a good design for 5.50 MHz. I

Re: [time-nuts] WTB: GPSDO

Hi > On Mar 14, 2017, at 6:33 PM, Tim Lister wrote: > > On Fri, Mar 10, 2017 at 2:35 PM, Chris Albertson > wrote: >> A GPSDO is not hard to make. All you need is some way to compare the >> phase of two signals, an XOR gate can do that. Then a

Re: [time-nuts] Bye-Bye Crystals

ere you need the real > deal or the right stuff. > > Cheers, > Magnus > > > On 03/14/2017 01:06 PM, Bob Camp wrote: >> Hi >> >>> On Mar 14, 2017, at 3:19 AM, Chris Albertson <albertson.ch...@gmail.com> >>> wrote: >>> >>> I

Re: [time-nuts] Bye-Bye Crystals

Hi > On Mar 14, 2017, at 8:49 AM, jimlux <jim...@earthlink.net> wrote: > > On 3/14/17 5:04 AM, Bob Camp wrote: >> Hi >> >>> The cost difference between a complete oscillator package and a simple >>> crystal is tiny. The osc is often cheaper if yo

Re: [time-nuts] Bye-Bye Crystals

gt;> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Bye-Bye Crystals >> >> I got a job in 1975 to design Konel's first synthesized radio, which >> was to obsolete their crystal controlled radios. That's over 40 years >> ago. The o

Re: [time-nuts] Bye-Bye Crystals

Hi > On Mar 14, 2017, at 4:44 AM, Hal Murray wrote: > > > artgod...@gmail.com said: >> I'm not after quality - I do have an application in mind but it doesn't need >> to compete with mass production. Just wondering if it's feasible to make >> something crude that will

Re: [time-nuts] Bye-Bye Crystals

Hi If your application is happy with 0.1% accuracy, you use a simple crystal that costs < 10 cents. If your application requires <0.001% accuracy, you probably are better off using a packaged oscillator. Bob > On Mar 13, 2017, at 8:11 PM, Hal Murray wrote: > > >

Re: [time-nuts] Bye-Bye Crystals

Hi If you are not to picky, you can buy crystals in bulk for < 5 cents each. Why make them from scratch? Best guess is that in small volume, they will cost you > $20 each to make. Labor cost something …. Bob > On Mar 13, 2017, at 9:09 PM, Adrian Godwin wrote: > > I'm

Re: [time-nuts] Bye-Bye Crystals

zero-charlie > > -Original Message- From: Bob Camp > Sent: Monday, March 13, 2017 5:19 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Bye-Bye Crystals > > Hi > > …. ummm …. errr … Add to that: > > X-ray gear to

Re: [time-nuts] Bye-Bye Crystals

Hi > On Mar 13, 2017, at 7:12 PM, jimlux <jim...@earthlink.net> wrote: > > On 3/13/17 3:19 PM, Bob Camp wrote: >> Hi >> >> …. ummm …. errr … Add to that: >> >> X-ray gear to work out the orientation of the (possibly natural) bar you are >

Re: [time-nuts] Bye-Bye Crystals

Hi …. ummm …. errr … Add to that: X-ray gear to work out the orientation of the (possibly natural) bar you are sawing Lapping gear to get the blanks flat (as optically flat) Automated / sorting X-ray gear to figure out what’s what after they are lapped Rounding equipment to turn the square

Re: [time-nuts] Bye-Bye Crystals

got a job in 1975 to design Konel's first synthesized radio, which > was to obsolete their crystal controlled radios. That's over 40 years > ago. The other trend (not mentioned) is that since 20 years ago or > so, complete oscillator sales have vastly outnumbered sales of loose > crys

Re: [time-nuts] Bye-Bye Crystals

Hi International’s main business was re-channeling non-synthesized radios and replacing broken crystals in various pieces of com gear. It’s been a *lot* of years since the last of the non-synthesized radios came out. The business probably has been dropping off pretty steadily for many

Re: [time-nuts] Thunderbolt Rollover Testing

Hi > On Mar 6, 2017, at 1:38 AM, Mark Sims wrote: > > Does it have a saved/surveyed position? With a saved position you can > reasonable time performance with 1 sat. Without a saved position all bets > are off, there is no way for the receiver to determine the >

Re: [time-nuts] RFDO - Experience and questions

Hi One way to “cheat” at recovering a time signal is to demodulate it with known information. Once you know the information from the first “frame” of data (time, date, etc) you can predict what the information in the next frame will be. Yes it does take a little work. If the signal is completely

Re: [time-nuts] Fwd: Dusty 53131A

Hi 53131’s are dust magnets. It is not at all uncommon for them to fill up with dust, overheat, and die. Popping them open every 10 years or so to clean them out is well worth the effort. Bob > On Mar 5, 2017, at 8:54 PM, Scott Stobbe wrote: > > Recently the fan

Re: [time-nuts] Thunderbolt Rollover Testing

Hi > On Mar 5, 2017, at 6:31 AM, Trevor N. wrote: > > On Sat, 4 Mar 2017 20:39:45 -0800, you wrote: > >> Matthias Jelen did a test on the Trimble Thunderbolt here: >> >> https://www.febo.com/pipermail/time-nuts/2014-September/086664.html >>

Re: [time-nuts] Coming to a drive-way near you: Optical Lattice clocks

Hi > On Feb 24, 2017, at 5:02 AM, Michael Wouters <michaeljwout...@gmail.com> > wrote: > > On Fri, Feb 24, 2017 at 10:27 AM, Bob Camp <kb...@n1k.org> wrote: >> Hi >> >> I agree with their premise that to be useful you need transportable clocks. >&g

Re: [time-nuts] Coming to a drive-way near you: Optical Lattice clocks

Hi I agree with their premise that to be useful you need transportable clocks. I’m not quite sure that something the size (and weight) of a pickup truck is really transportable. Yes one can move it around (unlike a small mountain) …. Transporting something like that from here to Europe and

Re: [time-nuts] TTimelab question

Hi > On Feb 21, 2017, at 11:45 PM, Mark Sims wrote: > > I doubt that it is something TAPR would do. Building complete systems gets > into all sorts of issues (mainly regulatory). There’s also the issue of cost. If you need to sell maybe 200 gizmos at $100 to make

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPSdecoding cards

Hi > On Feb 21, 2017, at 9:50 PM, Trevor N. wrote: > > On Tue, 21 Feb 2017 07:37:34 -0500, BC wrote: >> >> Some 1588 chip sets have (or had, I haven’t looked recently) external sync >> pins. >> This does get into the whole, what’s a motherboard / what’s a peripheral >>

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPSdecoding cards

Hi > On Feb 20, 2017, at 9:26 PM, Trevor N. wrote: > > SA6CID wrote: >> >> So, I thought actually of the jitter added on the way between our >> accurate source (GPS rx), until we can capture our timer. How much can >> this be? As far as I see we don't have a capture mode

Re: [time-nuts] Have done some more cutting on the Cs beam tube

Hi The high performance tube runs at a higher beam current than the standard tube. One would guess that a bit more Cs boils off to supply the beam at the higher temperature. There are rumors that the high performance tubes were “selected” out of the batch. Even if that was once true, who knows

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

else to brew up the peripheral you need. Bob > On Feb 18, 2017, at 10:45 AM, Thomas Petig <tho...@petig.eu> wrote: > > Hi Bob, > > On Sat, Feb 18, 2017 at 08:36:51AM -0500, Bob Camp wrote: >> Hi >> >>> On Feb 18, 2017, at 4:53 AM, David J Taylor

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

Hi > On Feb 18, 2017, at 4:53 AM, David J Taylor > wrote: > > Hi, > > I was wondering whether there is some data/information available on the > claimed +/- 100 ns jitter? I guess the previous was not complete enough. I routinely measure PPS jitter on GPS

Re: [time-nuts] Installing GPS Antenna

Hi Let’s back off a bit here. If the chimney is above the rest of the house, simply putting the antenna a foot or two above the chimney will get you past the immediate issues of the house blocking or reflecting stuff. If the top of the chimney has a view to the south down to about 10

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

s > DK6KD > SA6CID > > PS: > Raw data is here, if you want to zoom in: (1.7 MiB, one row per PPS > offset in us) > http://petig.eu/pps-usb.txt > > On Tue, Feb 14, 2017 at 07:26:23AM -0500, Bob Camp wrote: >> Hi >> >> A direct port might be a +/- 100

Re: [time-nuts] Problems with CHU

Hi Not quite sure what happened to the original message before it got here … The voice / time announcements on WWV and CHU date back quite a ways. I wonder just how old the gear they currently are using is? Once upon a time it was done with a mechanical marvel of a device. Bob > On Feb

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

Hi Whatever you do on the server, the same impacts will be felt on the client side. You may be able to do this or that on a server to allocate resources. On a client workstation, resource allocation is likely to be a bit more difficult. You may not even have control over which OS is being

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

Hi > On Feb 16, 2017, at 1:30 AM, Ruslan Nabioullin wrote: > > On 02/15/2017 01:17 PM, Chris Albertson wrote: >> Why set up a dedicated NTP server if you only have two computers >> that will use it?Your server will be accurate to a few >> microseconds but your two

Re: [time-nuts] Vintage Frequency Measurement

Hi Silly Canadians :) It seems that the term either has drifted a bit over the last 70 years or there is indeed another British / US difference here. Bob > On Feb 15, 2017, at 5:00 PM, iovane--- via time-nuts > wrote: > > This Canadian RCA apparatus was also called

Re: [time-nuts] Vintage Frequency Measurement

t; http://www.vmarsmanuals.co.uk/archive/724_Wavemeter_Class_D_No2_Working_Instructions.pdfSo > here in the UK the 221 was often also called a wavemeter. Classic wavemeters > were also available for example the Marconi TF975. > Robert G8RPI. > > From: Bob Camp <kb...@n1k.org> > To: Discussion of pre

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

Hi > On Feb 14, 2017, at 9:23 PM, Chris Albertson > wrote: > > On Tue, Feb 14, 2017 at 7:31 AM, MLewis wrote: > >> >> >> - a dedicated machine/box for unencumbered acceptance of PPS, and >> - for systems with a business need, a dedicated

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

/www.newegg.com/Product/Product.aspx?Item= >> N82E16813157497_re=j1900-_-13-157-497-_-Product> >> >> There are other boards like this that use the same J1900 CPU. I'm >> thinking about using this as th machine tool (milling machine) controller. >> >> On Tue

Re: [time-nuts] Vintage Frequency Measurement

sure what it would be. > > Interestingly they describe the thermometer as space-saving and trouble > free alternative to a heater and thermostat apparatus (I guess they weren't > called ovens yet?) > > On Mon, Feb 13, 2017 at 10:11 PM, Bob Camp <kb...@n1k.org> wrote: > >> Hi &g

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

Hi > On Feb 14, 2017, at 10:31 AM, MLewis <mlewis...@rogers.com> wrote: > > > > On 14/02/2017 7:26 AM, Bob Camp wrote: >> Hi >> >> A direct port might be a +/- 100 ns sort of thing most of the time and a >> +/-10 us >> thing every so of

Re: [time-nuts] Vintage Frequency Measurement

gt; wrote: > > just be careful, because if you under-heat the cathode you could kill it > > 73 > > Alex > > > On 2/13/2017 7:11 PM, Bob Camp wrote: >> Hi >> >> >>> On Feb 13, 2017, at 8:15 PM, Scott Stobbe <scott.j.sto...@gmail.com> wro

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

Hi A direct port might be a +/- 100 ns sort of thing most of the time and a +/-10 us thing every so often under some OS’s. Most desktop operating systems are not designed to prioritize random pin interrupts. A dirt cheap MCU coded with a few (hundred) lines of assembly code may be a better

Re: [time-nuts] Vintage Frequency Measurement

Hi > On Feb 13, 2017, at 8:15 PM, Scott Stobbe <scott.j.sto...@gmail.com> wrote: > > On Mon, Feb 13, 2017 at 6:41 PM, Bob Camp <kb...@n1k.org> wrote: > >> >> >> I think what you would find is that it *is* a fairly normal AT cut and the >> da

Re: [time-nuts] Vintage Frequency Measurement

Hi > On Feb 13, 2017, at 10:35 AM, Scott Stobbe wrote: > > Hi Mike, > > First of all, Wow what an interesting read, thanks for sharing some of the > history and your experiences with the 105. A second thanks for uploading > the manual, which I found to be a great

Re: [time-nuts] Vintage Frequency Measurement

Hi With a VFO running, you have a heterodyne frequency meter. That is (at least to me) a very different device than an absorption wave meter. I know way to put power into a BC-221 and use it as an absorption device. I’m not in any way saying that the LM or the 221 are less useful. They are

Re: [time-nuts] Vintage Frequency Measurement

Hi Ok, so how does that make a BC-221 a wave meter? Bob > On Feb 12, 2017, at 7:15 PM, Wes <w...@triconet.org> wrote: > > On 2/12/2017 12:51 PM, Bob Camp wrote: >> Hi >> >> Maybe I’ve been wrong for the last many decades … >> >> To me a wave m

Re: [time-nuts] Vintage Frequency Measurement

Hi The GR is a classical wave meter that works off of a tuned circuit and a broadband detector. The BC-221 works on an entirely different principle and has no ability at all to run in the mode that the GR operates in. Bob > On Feb 12, 2017, at 9:13 PM, Alan Hochhalter

Re: [time-nuts] Vintage Frequency Measurement

Hi If you look at a typical BC-221 in use, it goes from “calibrated” in a nice warm hut to the back of a jeep. It heads out to an ice cold flight line and the switch turns the batteries back on again. It bumps in and out of a batch of B-17’s setting each one up for the day’s net frequencies.

Re: [time-nuts] Vintage Frequency Measurement

Hi That’s not the *accuracy* of the crystal mind you. That’s how close you do the zero beat to something else that is more accurate. The crystal is out in the open and it drifts quite a bit as the unit warms up or changes temperature due to being moved around. Bob > On Feb 12, 2017, at

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

you do all three tests in parallel? One unit under test driving >> three counters. >> Each counter using a different reference signal, one on a OCXO, one on a >> rubidium, >> and one on a GPS disciplined oscillator. At each point in time during >> the test simply >

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

reference signal, one on a OCXO, one on a > rubidium, > and one on a GPS disciplined oscillator. At each point in time during the > test simply > choose the one that gives the best ADEV? > > Pete. > > On 2/11/2017 6:52 PM, Bob Camp wrote: >> Hi >> >> Usin

Re: [time-nuts] Vintage Frequency Measurement

Hi Maybe I’ve been wrong for the last many decades … To me a wave meter is a tuned circuit device that tells you the frequency by a resonance peak. They are a very common old school item for microwave frequency measurement in a teaching setting.

Re: [time-nuts] Vintage Frequency Measurement

Hi Counters go back at least into the early 1950’s. I started out with fully vacuum tube (except for diodes) counters obtained as surplus in the mid 1960’s. They used some odd gas filled triodes. Everything in them could have been on the market in 1947. They were not a common thing until the

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

two > regions using difference references for each? If so, are there generally > accepted "gold" standards anyone can recommend for crystal products with the > best stability to use as a reference between 0.1 and 100 seconds, for > example? > > > > On February 11, 20

Re: [time-nuts] Neoprene rubber drops GPS multipath signals to zero

Hi For any microwave material, the good old “toss it in a microwave” test is a quick and dirty one. If the material heats up, it’s lossy. Yes, there are other fairly exciting things that can happen other than it warming a bit …. Bob > On Feb 11, 2017, at 5:51 PM, MLewis

Re: [time-nuts] The USFS Frequency Standard...

Hi One *could* make a WWVB “new modulation” receiver with some sort of MCU demo board and a handful of parts. It would be fine for a basement lab / learning sort of project. Given the way the semiconductor world works, the longer you wait to start that project, the better a board you will have as

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

Hi Backing up a bit here. > On Feb 10, 2017, at 7:35 PM, gkk gb wrote: > > Hello experts, I need a Rubidium frequency reference for my company, and > wonder if I also need to GPS discipline it. > > > I characterize crystal-based OCXOs for ADEV, MTIE, and TDEV, and my

Re: [time-nuts] Line Frequency standard change - Possible ?

Hi To be fair to these guys, they have a number of challenges that have nothing to do with technology. They cross link to other companies and have little control over how each one operates. Here in the US, we have multiple regulatory agencies (it happens at the state, federal, and international

Re: [time-nuts] The USFS Frequency Standard...

Hi The simple answer is that WWVB still has the good old AM modulation on it. Any of the old *time* receivers will work just fine with the current broadcast format. There are a number of them that show up on the surplus market. The gotcha is those receivers that wanted to get both frequency and

Re: [time-nuts] Line Frequency standard change - Possible ?

Hi > On Feb 9, 2017, at 6:55 PM, Poul-Henning Kamp wrote: > > > In message >

Re: [time-nuts] Line Frequency standard change - Possible ?

Hi If you are talking about big power gizmos, putting a GPSDO on them is pretty simple cost and system wise. Given the fact that 10 ns sync is not required, the actual implementation might be pretty cheap. Bob > On Feb 9, 2017, at 5:19 PM, Peter Reilley wrote: >

Re: [time-nuts] Line Frequency standard change - Possible ?

> On Feb 9, 2017, at 4:31 PM, Poul-Henning Kamp wrote: > > > In message > <4fbdd81ddf04fc46870db1b9a747269202916...@mbx032-e1-va-8.exch032.ser > verpod.net>, "Thomas D. Erb" writes: > >> I was wondering if anyone was familiar with this proposal, is this >> a

Re: [time-nuts] eLoran is up and operating. Looking good

Hi P > On Feb 7, 2017, at 11:17 PM, Gary E. Miller <g...@rellim.com> wrote: > > Yo Bob! > > On Tue, 7 Feb 2017 21:38:52 -0500 > Bob Camp <kb...@n1k.org> wrote: > >> Teaching >> the NTP drivers when not to use the data and how to compare data is a

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