Re: [time-nuts] Terminators on empty outputs/connectors

As usual, the answer is "it depends." If the output is a single isolated output, then terminating load not required, but no harm providing. If the output is a multiple output, from a single driver, through a resistive or transformer splitter, then the level stability on all ports and the port to

Re: [time-nuts] suggestions on getting 24 Mhz ?

Phase noise is (usually) more important than absolute frequency accuracy. I suggest some kind of low phase noise master oscillator (OCXO) feeding a DDS without an internal multiplier. If internal multiplier in DDS, that, rather than the frequency reference source will set the phase noise floor

Re: [time-nuts] WWVB Time

Did you move it near a desktop PC or other computer, or move a desktop, or other PC, video screen or switching power supply in the vicinity of the Symmetricom or WWVB antenna? I am learning the hard way that PC and LED/LCD video screens are horrible generators of noise in the LF spectrum. ---

Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

> The Chinese have no concept of, or ignore, intellectual property rights. Do not forget that China is a communist government and culture.. And has been since about 1948. So no one left who was raised under a different system of government. Under communism, every thing is owned by "the people."

Re: [time-nuts] "Confessions of a Reformed Frequency Standard Nut"

And if I do some longer term averaging, I can get another one after that. :-) --- Graham == On Fri, Jan 19, 2018 at 11:16 AM, Ron Bean wrote: > https://hackaday.com/2018/01/17/confessions-of-a-reformed- > frequency-standard-nut/ > > "Or are you chasing that last

Re: [time-nuts] minimalist sine to square

SN65LVDS34D --- Graham / KE9H == On Fri, Jan 19, 2018 at 3:45 PM, Vlad <t...@patoka.org> wrote: > > > On 2018-01-19 14:31, Tom Van Baak wrote: > >> John's TADD-2-mini [1] uses the Wenzel sine-to-square converter. It >> performs very well but requires +10 V. >&

Re: [time-nuts] Weird GPSDO behavior

Could be a delivery truck with a GPS jammer on it, that passes your location every morning at the same time. --- Graham == On Fri, Sep 29, 2017 at 7:18 AM, Bob kb8tq wrote: > Hi > > > > On Sep 28, 2017, at 6:59 PM, Mark Sims wrote: > > > > I suspect that it

Re: [time-nuts] Ships fooled in GPS spoofing attack suggest Russian cyberweapon

Remember the military drone that the Iranians tricked into landing in Iran a few years ago? The best explanation I heard of how they did it was that they knew that if it lost its command channel, that it would return to the airport where it took off. So, what they did was spoof the GPS with a

Re: [time-nuts] Thunderbolt - trouble locking with some types of antennas

Dider: This is a CDMA signal. (With a 'chip' rate that far exceeds the information rate.) If you put a different correlator on every multipath signal, which are each differently delayed in time, then they can be independently demodulated. (Or time shifted and added back together with some

Re: [time-nuts] A look inside the DS3231

The typical method of frequency correction is not to add or subtract capacitance across the crystal, (like an old analog engineer would do) but rather to add or subtract pulses to the stream of cycles/pulses coming out of the crystal oscillator. More the kind of correction a digital engineer would

Re: [time-nuts] A look inside the DS3231

nctioning as advertised, it also is legitimate. If it is a clone, it's > a goood one, but I don't think it is. > > Cheers! > -Pete > > -- > Pete Stephenson > > On Thu, Jul 27, 2017, at 10:34 PM, Graham / KE9H wrote: > > Pete: > > > > If you are co

Re: [time-nuts] A look inside the DS3231

die. So, when they copied the die, they really just copied it. Didn't change a thing. It was not like they redesigned it, or were selling their own design with equivalent functionality. --- Graham / KE9H == On Thu, Jul 27, 2017 at 2:31 PM, Pete Stephenson <p...@heypete.com> wrote: &g

Re: [time-nuts] Hints on PPS Buffer design...

Read the spec sheet on the part you are using for a driver. The size of the resistor on the paralleled driver side will be set by the maximum current of the devices. Decide how conservative a design you want. Do you want it to drive into a shorted load and survive? [If each output is rated at 20

Re: [time-nuts] TruePosition on the Arduino

it when the serial message shows up. --- Graham / KE9H == On Tue, Jun 6, 2017 at 6:46 PM, Ben Hall <kd5...@gmail.com> wrote: > Good evening all, > > There is a saying: "a man with one watch knows the time, a man with two is > never sure." Clearly, this man wasn't a

Re: [time-nuts] Time-nut going England!

If you have never seen them, you must make a pilgrimage to see the Harrison Clocks at the Greenwich Observatory. If you have not read the book, you must read the book "Longitude" before seeing the clocks. --- Graham On Wed, Apr 26, 2017 at 8:05 AM, Attila Kinali wrote: > Hi

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

Anders: What antenna are you using that you call the "mini-whip?" Specifically, how long is the "whip?" Thanks, --- Graham == On Mon, Mar 6, 2017 at 3:57 AM, Anders Wallin wrote: > FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few days > ago.

Re: [time-nuts] Autodesk Eagle -- maybe they're listening

Or, switch to the best "free" open source solution, which is KiCad. Eagle had a bunch of quirks. I hear KiCad has a different set of quirks. So a learning curve to get up on KiCad and, for me, an issue migrating ten years personal library of component foot-prints. I heard a blogger suggest

Re: [time-nuts] Autodesk Eagle -- maybe they're listening

Mike: You can get Eagle 7.7 at: ftp://ftp.cadsoft.de/eagle/program/7.7/ Somehow, that ftp server is still up and serving downloads. --- Graham == On Mon, Jan 23, 2017 at 6:56 PM, Mike Suhar wrote: > Many companies are trying to jump on the subscription band wagon. It is

Re: [time-nuts] Autodesk Eagle -- maybe they're listening

Hi John: It is still an effective tripling or quadrupling of the cost. I purchased a "non profit" license several years ago for $129. "Non commercial, 4 layers, up to 160 sq cm., all functionality enabled." They converted this to a "standard" license over time. A license was good for the life

Re: [time-nuts] OT: Eagle PC CAD now Autodesk, $500/year

Your existing Eagle license should allow you to run your existing version indefinitely. I think it would be useful for a few years or so. I also think your existing license also allows you to run one copy on Mac, Linux or Windows. So, if you are on Windows 7 and think you might want to migrate to

Re: [time-nuts] Lady Heather Version 5 is now available - date formats

How did the Mayans deal with leap seconds? --- Graham == On Tue, Dec 13, 2016 at 4:28 AM, Mark Sims wrote: > Heather defaults to the unambiguous format 13 DEC 2016. There is a > command for showing the date in the ISO format -ddd where ddd is the > day of the year. >

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

Remember that the internal Voltage reference in the original three terminal regulator designs is a Zener. (Zeners are also useful as RF white noise sources.) The regulator is generally an amplifier with DC feedback. If you look at the application notes on the early regulators, they require

Re: [time-nuts] RPi/ beagle bone-like computer without video

If you are going to go battery powered, I would also recommend staying away from Linux, go with something like a 32 bit PIC32MX or PIC32MZ. Full Ethernet stack, RTOS if you need it, can do deep sleep down into the microamp range when not active. --- Graham. On Wed, Nov 30, 2016 at 8:35 PM, Gary

Re: [time-nuts] RPi/ beagle bone-like computer without video

The BeagleBone Green is a BeagleBone Black with the HDMI and video chip removed. Mouser Part number *Mouser Part #: *713-102010027, $39, In stock. Makes a great little headless server. --- Graham == On Wed, Nov 30, 2016 at 3:51 PM, Clint Jay wrote: > Raspberry Pi

Re: [time-nuts] Inductor core material aging (was: Rohde & Schwarz XSD 2.5 MHz crystal gone bad?)

The core of the inductors are commonly powdered iron (of various alloys), held together with a plastic binder. The early plastics shrank and changed shape with time, changing the inductance over decades. Later binders are much more stable. Not much you can do about it, other than change the

Re: [time-nuts] Rohde & Schwarz XSD 2.5 MHz crystal gone bad?

Is your oven doing what it is supposed to be doing? Sounds more like an oven problem than a crystal problem. --- Graham == On Sun, Nov 20, 2016 at 7:00 PM, Alan Melia wrote: > Michael a couple of wild thoughts, make sure there is no 500kHz there > (this is the

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

You need a definition of "Quality" to work with. One definition might be "does it meet published specs? under what conditions?" Another definition might be associated with reliability and ruggedness. Longevity in outdoor conditions. Another might be with the antenna supporting your use case.

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

If you are in a position where you are worried about damaging the PCB. (And I would really be worried cutting any part in half with cutters, or cutting leads off an IC with diagonal cutters.) For two leaded parts, "Hot tweezers" work fine. For parts with more leads, like ICs, you need hot air

Re: [time-nuts] Opening an Isotemp OCXO

Here is the TI document on "Case Marking." It may not be a 74S30. http://www.ti.com/lit/an/snoa039c/snoa039c.pdf --- Graham == On Fri, Oct 28, 2016 at 11:27 AM, Adrian Godwin wrote: > That's one sweet soldering iron. Is it an American Beauty ? > > > On Fri, Oct 28, 2016

Re: [time-nuts] For those that insist on using switching power supplies

Actually, if they have the "CE" stamp on the product, then they have very specific radio interference limits that they must test and meet. It must have been tested, certified, and the certification package available for inspection. Whether they actually met it, then pulled the interference

Re: [time-nuts] New PPB rated TCXO

If you have a legitimate application for the part, and some volume associated with the application, and you convince their sales person of that, then the data sheets are made available. --- Graham On Tue, Oct 11, 2016 at 8:01 AM, jimlux wrote: > On 10/10/16 11:27 PM, djl

Re: [time-nuts] Need Time Help

For the group. This ham is trying to work EME. Earth-Moon-Earth propagation path. Aka, "moonbounce." He is trying to time synchronize a system, where the other station he is communicating with can be any other place on the Earth that can also see the Moon. So the system time sync is for a little

Re: [time-nuts] Need Time Help

al time OS, such as Linux with a real-time kernel. This does not cure the problem, but does put bounds on it. --- Graham / KE9H == On Tue, Oct 4, 2016 at 7:03 AM, Bob Camp <kb...@n1k.org> wrote: > Hi > > As others have mentioned, you have two strikes against you: > > 1) Mod

Re: [time-nuts] Subject: Re: Working with SMT parts (Bob Albert)

A good source for experimenters / home builders of small quantities of tin-lead solder paste is: http://kd5ssj.com/ http://kd5ssj.com/solderpaste The supplier, Cash Olson, KD5SSJ, is an amateur radio operator that for some extra pocket money in his retirement, repackages fresh Kester 256 solder

Re: [time-nuts] Working with SMT parts.

The best type of stereo microscope to use for SMT assembly is referred to as an "Inspection Microscope." Magnification greater than 10 is not needed or desirable for normal assembly. Something in the range of 5 to 10 works well. A wide field of view and a good light source are desirable. Just as

Re: [time-nuts] phase noise in digital divider, 2nd harmonic

It is not traditional phase noise, and not a normal Nyquist filtering problem, but, yes, presence of significant second harmonic energy in your DDS output will shift/dither your squaring input. It is hard, with practical filters and filter components to get much better coverage than one-half

Re: [time-nuts] Q/noise of Earth as an oscillator

42 On Sat, Jul 23, 2016 at 7:59 PM, Hal Murray wrote: > > t...@leapsecond.com said: > > Earth is a very noisy, wandering, drifting, > incredibly-expensive-to-measure, > > low-precision (though high-Q) clock. > > What is the Q of the Earth? It might be on one of your

Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

Don Latham said to Discussion I do not see why a small pick and place assist system could not be built on a 3-d printer. Lots of problems to be solved... How do you take loose parts or cut tape or tape reels and get the right part out, and into the chuck, oriented in the right direction? How

Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

We use "Advanced Assembly" in Colorado for prototype assembly. http://aa-pcbassembly.com/ For just one or two boards, it is faster to hand solder the parts, as long as no BGA's or similar. If complex soldering like BGAs, or more than three boards, we use a proto assembly house. --- Graham ==

Re: [time-nuts] Measuring receiver...

This is heavily used in cellular system security and cellular unit identification and tracking. Do a google search on patents using the the term "RF fingerprinting" and you will get quite a few hits. Mostly recent application to cellular systems. You might look at the prior art listings and see

Re: [time-nuts] HF frequency counting receiver

Most of the folks doing the FMT these days use some sort of audio spectrum analyzer program and estimate the frequency using that. Or use the audio spectrum analyzer to measure the difference between the frequency being measured and the precision reference. You are correct, it is usually not a

Re: [time-nuts] HF frequency counting receiver

You need to be able to measure frequency accurately in the milli-Hertz range to be competitive in the frequency measuring contests. I doubt the Selective Voltmeters have that level of resolution. I think they 'only' read to 0.1 Hz. --- Graham On Mon, Jun 20, 2016 at 11:52 AM, Pete Lancashire

Re: [time-nuts] HF frequency counting receiver

Nick: You can do it this way, but it requires you to totally understand the mathematics and granularity of ALL of the frequency sources and synthesizers in the superhet receiver. And if there are any audio soundcards or sampling devices involved, the specifications and origin of the sampling

Re: [time-nuts] Simple solution for disciplining OCXO with 1 PPS

If you want an "existence proof" for a simple, mostly analog, a few digital counters, no software or microprocessor GPSDO, look at the "Miller" GPSDO. He designed it for his own use, then put it into production because of demand for a simple, cheap GPSDO. It has been characterized, and works well

Re: [time-nuts] AM335x/Beaglebone Black memory bus (was: 1 PPS 50-ohm driver)

I think the more common way to do this is SPI or the I2S / DSP type transfer formats. You are likely to find existing Verilog modules that do these transfer formats. --- Graham / KE9H == On Mon, Apr 18, 2016 at 2:10 AM, Attila Kinali <att...@kinali.ch> wrote: > On Sun, 17 Apr 2016

Re: [time-nuts] Building a mains frequency monitor

For all you Powerline Time nuts, and maybe GPSDO time nuts, too. Consider this new PIC.PIC16F1619 $1.60 USD, quantity one at Mouser. It was designed to be an AC motor controller. So has some interesting built in hardware peripherals: Mains Zero crossing detector. Runs up to 32 MHz

Re: [time-nuts] Advise on building a DIY GPSDO?

The lowest jitter way to do this kind of conversion is to multiply the signal up to some common multiple frequency, then divide it back down to where you want to be. For instance, with 8 or 24 MHz, multiply up to 240 MHz, then divide by 24 to get 10 MHz. Modern clock generator chips have this

Re: [time-nuts] Microsonics TCXO

to Moore's Law. https://upload.wikimedia.org/wikipedia/commons/0/00/Transistor_Count_and_Moore's_Law_-_2011.svg --- Graham / KE9H == On Sun, Mar 20, 2016 at 12:42 AM, Joseph Gray <jg...@zianet.com> wrote: > I got my hands on some of these. > > https://dl.dropboxusercontent.com/

Re: [time-nuts] Inside a CTS 1960017 OCXO

Rob: Are you sure you were running it with a clean power supply? Any 60 Hz ripple on the supply could show up as AM/PM modulation. You might want to try another 5V power supply before you give up on the oscillator. --- Graham On Sat, Feb 27, 2016 at 11:35 AM, Rob Sherwood. wrote:

Re: [time-nuts] Inside a CTS 1960017 OCXO

they solicit you, or did you solicit them for the work? Or did they just see and copy your stuff on Oshpark? --- Graham / KE9H On Sat, Feb 27, 2016 at 10:48 AM, Daniel Watson <watsondani...@gmail.com> wrote: > Hi, > > I'm sure many of you are tracking the cheap CTS 10MHz OCXOs avai

Re: [time-nuts] Z3801 Newbie Question

. Just cant > explain why all of us see a sporadic jumps in PPS error for an hour or two > once or twice a day > > Dave > NR1DX > ArtekManuals.com > > A man with a watch always knows what time it is > A man with two watches is never quite sure > > . On 1/28/2016 6:23 P

Re: [time-nuts] Z3801 Newbie Question

Please describe your Antenna setup and location. How much of the sky can it see, in which directions. Which directions are blocked for direct line of sight, and must depend on reflections from nearby buildings or objects? --- Graham == On Thu, Jan 28, 2016 at 11:25 AM, Tom Van Baak

Re: [time-nuts] low noise multiplication to 100 MHz

There are clock distribution parts designed to do this low noise frequency conversion and distribution. Consider TI LMK04100 Ignore PLL1 Put your 10 MHz as the reference input to PLL2. Set Internal VCO to ~1200 MHz Set the internal dividers to get 100 MHz out, and 10 MHz back to the PLL2 phase

Re: [time-nuts] PRS10 C900 replacement

You will need to know the capacitance value. Usually expressed in uF (micro Farad). Then some idea of the physical size, so the replacement will fit in the current space. --- Graham == On Tue, Jan 19, 2016 at 4:21 PM, davidh wrote: > Hi All, > > While still appearing to

Re: [time-nuts] Generating a solid PPS from 10Mhz source

The programmable PIC or AVR or ... chip that will do the job are same or less than a 555 chip, and a lot more flexible. --- Graham On Fri, Jan 15, 2016 at 11:55 AM, Adrian Godwin wrote: > Why use a board full of TTL when an $1 8-pin chip will do it ? > > > On Thu, Jan 14,

Re: [time-nuts] beaglebone black, debian, NTP client

The Debian 8.x (jessie) releases for the BeagleBone run systemd-timesyncd, which is installed and on by default. As long as the Beaglebone is hooked to the internet, it has correct time to +/- 10 milliseconds or so. Probably good enough for a time-nut lawn sprinkler. systemd-timesyncd is a

Re: [time-nuts] PPS phase between two GPS units.

Are they running off the same power supply? If so, I would run them from different power supplies as an experiment. --- Graham == On Tue, Dec 22, 2015 at 6:19 AM, Attila Kinali wrote: > On Tue, 22 Dec 2015 11:57:55 +0100 > Mike Cook wrote: > > > > A

Re: [time-nuts] Need tiny 5MHz 10x amplifier

I would consider using a LVDS line receiver. http://www.digikey.com/catalog/en/partgroup/lvds-differential-line-receivers/11820 They are available in SOT-23 package, and can have built-in hysteresis, and 3.3V CMOS output. --- Graham == On Sat, Nov 28, 2015 at 6:35 PM, Poul-Henning Kamp

Re: [time-nuts] NAVSTAR proteus GPS time and frequency unit

GPS Time ignores (does not deal with) "Leap Seconds." It is dealt with in the software translation from GPS time to UTC or local time. That is part of the reason there is a 16 second time difference between GPS Time and UTC/local time. --- Graham == On Mon, Nov 9, 2015 at 4:15 PM, Chuck Harris

Re: [time-nuts] Bad date out of HP Z3805A

Yes, you are missing 1024 weeks. Google: GPS week rollover. --- Graham == On Sun, Nov 1, 2015 at 7:19 PM, Charlie wrote: > I have used a HP Z3805A for my shack for a number of years. I recently > wished to get the date output. Hooked up my laptop, and found that

Re: [time-nuts] Beginners GPS locked frequency counter question

Chris: If by "purely mathematical" you mean with infinite precision and infinite accuracy in the calculations, then the answer is "No." The counter is using integer mathematics, in a world with propagation delays and clock jitter, and uncontrolled phase relationships. So resulting rounding

Re: [time-nuts] Celestial Navigation instruction being reinstated in the US Navy

Both the sextant and the slide rule will still function after an EMP event. Not much other electronic stuff will. --- Graham / KE9H == On Mon, Oct 26, 2015 at 4:20 PM, paul swed <paulsw...@gmail.com> wrote: > Crazy bit of humor/timing in all of this I guess. > > Oddly at the

Re: [time-nuts] UBLOX LEA-5T Programming?

There is a lot of jitter on a GPS 1 PPS output. You need a big "flywheel" to smooth out the jitter errors. GPS modules only have room for small flywheels. --- Graham On Fri, Oct 9, 2015 at 9:16 AM, Clint Jay wrote: > I am still learning and want to understand, if the PPS

Re: [time-nuts] I've designed a GPSDO, but how good is it?

Nick: From your description, it sounds like you have a frequency locked loop with a maximum frequency sensitivity of 1 ppb, as opposed to a phase locked loop. At the end of the 100 second count period, do you start over with a counter set to zero, or do you carry forward any error from the

Re: [time-nuts] wtd: WWVB info

, the bandwidth will be nearly 96kHz, typically at least 80kHz, not limited to 20kHz. That is the POINT of 192kHz sampling. David N1HAC On 8/5/15 10:03 PM, Graham / KE9H wrote: Scott: You won't be able to use an off-the-shelf audio card, because they will have filters that cut off just

Re: [time-nuts] wtd: WWVB info

kHz. You would only need a preamp if you were running some negative gain antenna. Lots of dynamic range. Won't overload until 2 Volts peak-to-peak or so. A very simple, high performance digital receiver front-end. --- Graham / KE9H == On Wed, Aug 5, 2015 at 6:15 AM, Bob Camp kb...@n1k.org

Re: [time-nuts] wtd: WWVB info

, ie., no Tayloe mixer required. Just the (audio) data converter and the DSP. --- Graham / KE9H == On Wed, Aug 5, 2015 at 5:47 PM, Scott Newell newell+timen...@n5tnl.com wrote: At 12:40 PM 8/5/2015, Graham / KE9H wrote: Content-Transfer-Encoding: 8bit There are several high end audio Analog

Re: [time-nuts] 10MHz Square to Sine Wave Conversion

All you need is a 10 MHz low pass filter. How far down do you need the harmonics/spurious to be? If 40 dB suppression of the 2nd and 3rd harmonics is adequate, (you can't see the distortion with the eye on an oscilloscope) you can make your own for about $2 in parts, not including a PC board or

Re: [time-nuts] IRIG-B audio decoder circuits and ICs sought

Be aware that there are about 100 variations on IRIG B, that is, B000 through B257. You should obtain a copy of IRIG STANDARD 200-04, the 2004 version, which I believe is the most current. It is available on line, if you Google for it. --- Graham / KE9H == On Tue, May 19, 2015 at 8:11 PM, Neil

Re: [time-nuts] Mini-time lab cost and maintenance

Adam: It depends. What are you trying to do? How much accuracy is needed? Do you mean just time, or some other metrics, too? --- Graham == On Mon, Apr 6, 2015 at 11:30 AM, Adam Blakney akblak...@gmail.com wrote: I was wondering how expensive it would be to have even a small and lower level

Re: [time-nuts] Comparing the BeagleBone Black Raspberry Pi asNTP servers

David: If you are running headless, that is, not using the on board video-graphics system, all interaction with the unit is via the console, local or SSH. In this case, I would use the console version as described above. It is about one tenth the size of the version you are using. You will

Re: [time-nuts] Comparing the BeagleBone Black Raspberry Pi as NTP servers

David: On the BBB, were you running the fully loaded release, or the minimum console version of the OS? Which specific version of the OS? Thanks, --- Graham == On Sat, Mar 21, 2015 at 11:23 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: Folks, I've just put up my first draft of a

Re: [time-nuts] 50 ohm driver

a driver that can push sine-waves at over a few GHz. Not 10 MHz. --- Graham / KE9H == On Sat, Mar 7, 2015 at 7:58 AM, Didier Juges shali...@gmail.com wrote: Martyn, if you only need 1Hz, I recommend you use a MOSFET driver like the MIC4420 series or the UCC27531, powered from 10V with a 50 ohm

Re: [time-nuts] 50 ohm Driver

, but only draw one half the DC current. In the event of no input, the receiver voltage will go to half scale. Make sure your system will not misbehave when this happens. Alternate driver is to use a video line driver with sufficient bandwidth. --- Graham / KE9H == On Wed, Mar 4, 2015 at 7:54 AM, John

Re: [time-nuts] Motorola Oncore M12+T Sawtooth

line is supposed to change, but if it is a 20 MHz CPU clock, it can only change every 50 ns. The sawtooth correction is the difference between the constrained transition and the ideal transition. --- Graham / KE9H == On Thu, Jan 29, 2015 at 4:27 PM, Tom Van Baak t...@leapsecond.com wrote: google

Re: [time-nuts] Beaglebone NTP server

Neil Schroeder wrote: Graham make sure you read up on dtb and fdt. Many if not most distros don't have what you might call a default. I have done several device tree overlays on the BBB, so I think I can usually get the I/O lines and pin-mux to do what I want them to do. It was a total pain

Re: [time-nuts] Beaglebone NTP server

Dan: When you forced/locked the CPU frequency at 1 GHz, did you by any chance measure what it did to the CPU case/package temperature? Or current drain? I note that you used BBB pin P8.7 for PPS input. That allowed you to use it for either pps-gpio or TIMER4 pps-gmtimer, by just changing the

Re: [time-nuts] Beaglebone NTP server

. Thanks, --- Graham / KE9H == On Tue, Dec 9, 2014 at 11:18 AM, Bob Darlington rdarling...@gmail.com wrote: Hourly cron jobs, perhaps? -Bob On Tue, Dec 9, 2014 at 8:04 AM, David J Taylor david-tay...@blueyonder.co.uk wrote: Thanks for pointing this out David, Compiling an new kernel

Re: [time-nuts] Beaglebone NTP server

wrote: On Tue, Dec 9, 2014 at 12:59 PM, Graham / KE9H ke9h.gra...@gmail.com wrote: I guess I am asking if the kernel pps-gpio has a specific preferred pin, or whether it can be mapped to any available gpio pin. The provided-with-stock-dtb pin is: 0x40 which is P9 pin 15. I use the only

Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812A GPSDO system

Bill: On cable TV systems, 50 MHz to 500 (or higher) are the forward channel. (Head-end to client.) Below 30 MHz is the reverse channel, for data going from the client to the cable company. The band 30 to 50 is a cross over zone for the band splitting filters. It is designed to not amplify the

Re: [time-nuts] Really fast ADC needed

A startup in Massachusetts named Hypres has/had exactly what you want. It is a cryogenic delta-sigma converter using some kind of quantum logic. As I remember it did about four bits per sample at up to 40 Giga-samples per second. You have to run it submerged in liquid Helium. But they would sell

Re: [time-nuts] Is this measurement for real?

of the computer. --- Graham / KE9H == On 12/7/2013 2:24 PM, quartz55 wrote: I've been testing my soundcard measurement capability with Speclab, so I hooked my LPRO Rb to lock my Moto Service Monitor, fed the 1K audio out into the sound card and I measured the freq over about a half hour. I got

Re: [time-nuts] Strange 100ns jumps on Motorola M12+T

jump equal to the apparent change in location of the receiver, for the different solution. With heavy multi-path/reflections, antennas just a few cm apart will be looking at different solutions, and will jump time/location at different times. --- Graham / KE9H == On 11/19/2013 10:45 AM, Chris

Re: [time-nuts] Off Topic Sortof: Board Rework Stations

John: We have one at work. It basically works as represented. It takes some skill to run, and takes some time to develop the safe settings for soldering different sized items. It puts out a tremendous amount of infrared heat, and you can melt things if you are not careful. For instance, it

Re: [time-nuts] Surface Mount OCXO Questions

the oven. I have seen all three cases. As usual, it is suggested that you read the [] manual. Best regards, --- Graham / KE9H == On 10/29/2013 9:18 PM, John C. Westmoreland, P.E. wrote: Hello, I was wondering if I could get some recommendations on surface mount OCXO's vs. the traditional

Re: [time-nuts] Surface Mount OCXO Questions

On Wed, Oct 30, 2013 at 6:54 AM, Graham / KE9H time...@austin.rr.comwrote: John: All SMT OCXO's will either have a recommended PCB footprint in the spec sheet or will refer you to a recommended footprint in another document. Some don't care about a ground plane under the part, some require

Re: [time-nuts] Coax cable for volute antenna

Or contact Jeremy directly (W7EME) and see if he can help you out. --- Graham / KE9H == On 10/16/2013 11:30 PM, Jim Lux wrote: On 10/16/13 8:26 PM, quartz55 wrote: I've been searching for the small copper hardline I can use for the feed on the gps volute (egg beater) antenna. Can anyone steer me

Re: [time-nuts] HP E1938A Oscillator

? Instructions on how to calibrate and compensate it? My impression is that it is a lot easier for an experimenter to manage an HP10811 oscillator where you just put power on it and a signal comes out. Thanks, --- Graham / KE9H == ___ time-nuts mailing

Re: [time-nuts] Zendulum

On 6/8/2013 1:40 PM, Don Latham wrote: Neat! The path shape can be calculated to be isochronous, if I remember aright... Don Hi: Here's a kit I just built that's a pendulum that's a metal ball powered by a small solar cell. Haven't done any measurements yet, but the period is about a second.

Re: [time-nuts] NTP Clock suggestions?

Miguel: If you are going to build your own, I would recommend you start with something like the Microchip PIC32 Ethernet Starter Kit. Comes with a free GCC C/C++ compiler and an Ethernet stack. I happened to have one for another project, that already had a four line serial LCD display hooked to

Re: [time-nuts] NTP Clock suggestions?

On 5/27/2013 2:40 PM, Kenton A. Hoover wrote: A useful reference to own: http://www.amazon.com/gp/aw/d/0521702380/ref=mw_dp_sim_ss1?pi=SL500_SY125 -- Kenton A. Hoover ken...@nemersonhoover.org +14158305843 Kenton: Thanks. I ordered from Amazon. --- Graham ==

Re: [time-nuts] Follow-up question re: microcontroller families

On 5/25/2013 3:40 PM, Bob Camp wrote: You can get a part with 1MB of flash, 128KB of ram, 6 UARTS, 4 16 bit A/D's, 10/100 Ethernet, USB, and a bunch of other stuff for less than $10. Drop this and that, go to half the flash, and yup, the price is 1/2. Comes with a free toolchain and two

Re: [time-nuts] OT, looking for a good science forum

. Just pure acetone works well at dry ice temperatures. We used crushed dry ice in acetone as an alternative when the liquid nitrogen truck was late making its delivery for the cryro lab. --- Graham / KE9H == ___ time-nuts mailing list -- time-nuts

Re: [time-nuts] Thermal noise contribution to phase noise

temperature) and the single side band phase noise measurement, which only looks at half the noise, since it only looks on one side of the reference signal? --- Graham / KE9H == On 1/15/2013 1:38 PM, Bruce Griffiths wrote: I've noticed a disturbing tendency to quote the thermal noise contribution

Re: [time-nuts] Cell timing error

calculations. --- Graham / KE9H == ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.

Re: [time-nuts] Cell timing error

Greg: You should switch to Verizon. They are inherently accurate to milliseconds. Sub micro-seconds inside the base stations. --- Graham / KE9H == On 12/15/2012 12:51 PM, Greg Troxel wrote: In central mass, ATT and tracfone (? carrier) are showing phone times very close to 1 min slow

Re: [time-nuts] getting a grip on 10811 drift (trying to read my instruments)

Chris: This says your EFC circuit is not working, and you are only getting 0.05 Hz frequency change across the -5 to +5 EFC range. The spec on the HP10811 is 1.0 Hz minimum. And, yes, in a counter the EFC circuit is not used, so no one would know if it failed. It is very simple circuit. The

Re: [time-nuts] getting a grip on 10811 drift (beginner-ish question)

operation before they rejoin their spec sheet drift specification. --- Graham / KE9H == On 11/5/2012 8:49 AM, Chris Howard wrote: I built a GPSDO using my own power supply, a VE2ZAZ board, a Trimble Resolution T GPS and a surplus HP 10811 oscillator. I'm having a bit of trouble with it. I

Re: [time-nuts] getting a grip on 10811 drift (beginner-ish question)

operation before they rejoin their spec sheet drift specification. So, they will drift more for a little while, then settle down to meet or exceed the spec sheet. --- Graham / KE9H == On 11/5/2012 8:49 AM, Chris Howard wrote: I built a GPSDO using my own power supply, a VE2ZAZ board, a Trimble

Re: [time-nuts] multi time zone display for wall mounting?

On 10/9/2012 6:04 PM, Mark Sims wrote: Lady Heather supports a digital clock display. You can zoom it to full screen. It would not be difficult to add the two time zones to that display. You could use three of these: http://www.sparkfun.com/tutorials/47

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