Re: [time-nuts] Lightning arrestors for GPSDO antenna

2014-10-18 Thread Jim Lux
On 10/18/14, 2:05 PM, Bill Hawkins wrote: FWIW, when grounding the metal mast of a boat, three inch wide copper strap is used because it is a better RF conductor. The strap is available in marine supply stores. It's actually more about being convenient to install, and tradition. If you have a

Re: [time-nuts] Lightning arrestors for GPSDO antenna

2014-10-17 Thread Jim Lux
On 10/17/14, 6:26 AM, Chris Albertson wrote: On Thu, Oct 16, 2014 at 7:51 PM, Dave M dgmin...@mediacombb.net wrote: Thanks, Chris. I've done a bit or research on the subject, and think I have a reasonable grip on the necessary steps. I have an 8' ground rod driven into the ground directly

Re: [time-nuts] Lightning arrestors for GPSDO antenna

2014-10-17 Thread Jim Lux
On 10/17/14, 8:17 AM, Chris Albertson wrote: You can use metal conduit as the bonding conductor between grounding systems, for one thing. That works fine, but I think it is disallowed by the electrical code. If you used metallic conduit it MUST be grounded but you can't use it for

Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip Flop

2014-10-16 Thread Jim Lux
On 10/16/14, 3:59 AM, Bob Camp wrote: Hi I wonder what they are using for the “lpf / zero crossers” in that version. Aren't those the usual limiter chain? Described in earlier papers by the same folks. There was a lot of discussion about this architecture on the list a few years ago.

Re: [time-nuts] Lightning arrestors for GPSDO antenna

2014-10-16 Thread Jim Lux
On 10/16/14, 6:27 PM, Chris Albertson wrote: Lightening arrestors are an important part of a protection system but just installing some in the antenna cable is not going to help so much. You need a system approach. If you do it right you can take a direct hit The big problem with grounding is

Re: [time-nuts] Wine cooler as temperature chamber

2014-10-14 Thread Jim Lux
On 10/14/14, 6:13 AM, Chuck Harris wrote: Uhmm? How does that differ from any heat pump, such as say, a freon cycle refrigerator? The COP for thermoelectric coolers (heat moved vs power consumed), particularly at large delta T, is fairly poor, compared to heat pumps. A heat pump might

Re: [time-nuts] Wine cooler as temperature chamber

2014-10-13 Thread Jim Lux
On 10/13/14, 4:17 PM, ed breya wrote: I have this nice little thermoelectric 12-bottle wine cooler (about one cubic foot inside) that I've fixed twice already, and it just crapped out again. It's always the same thing - bad caps in the switching power supply - they're just too small to take the

Re: [time-nuts] GPS jump

2014-10-11 Thread Jim Lux
On 10/11/14, 8:08 AM, Bob Camp wrote: Hi To the extent that anything *is* locked, it’s been done for a lot longer than the 1980’s. Long before common view GPS, Loran-C observations (and corrections via clock trips) were used. You can look at it as a PLL, just a *very* fancy one with *very*

Re: [time-nuts] locking oscillators - an increase in power and/or stability ?

2014-10-11 Thread Jim Lux
On 10/11/14, 9:00 AM, cdel...@juno.com wrote: Came across this. Might be relevant. Cheers, Corby http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930008868.pdf a) Greater than 100% power combining efficiencies have been realized as predicted. This implies that the output power from the

Re: [time-nuts] Sun Outage

2014-10-10 Thread Jim Lux
On 10/9/14, 10:16 PM, Andy wrote: Bob Stewart b...@evoria.net wrote: It occurred to me that one could use satellite signals as a meteorological instrument to measure the water density in the atmosphere above you. I wonder if the NWS does that. WHy yes they do: that's what weather radar

Re: [time-nuts] Sun Outage

2014-10-10 Thread Jim Lux
On 10/10/14, 4:21 AM, Bob Camp wrote: Hi Bringing this back to GPS… The TV stuff is at about 8X the frequency of GPS. That makes a difference in terms of things like rain. That said, yes, there probably is some giant rainstorm that would impact GPS accuracy. Much more likely in a “I can only

Re: [time-nuts] fast switching quiet synthesizer

2014-10-08 Thread Jim Lux
On 10/8/14, 12:52 AM, Hal Murray wrote: br...@ko4bb.com said: Kratos (www.kratosepd.com) do fast switching synthesiser subsystems that can be locked to a reference.. What does fast switching mean in the context of a DDS? How long does it take to load the new phase increment in? I

Re: [time-nuts] fast switching quiet synthesizer

2014-10-08 Thread Jim Lux
On 10/8/14, 7:21 AM, Bob Camp wrote: Hi On Oct 8, 2014, at 3:52 AM, Hal Murray hmur...@megapathdsl.net wrote: br...@ko4bb.com said: Kratos (www.kratosepd.com) do fast switching synthesiser subsystems that can be locked to a reference.. What does fast switching mean in the context of a

[time-nuts] fast switching quiet synthesizer

2014-10-07 Thread Jim Lux
At work, I'm putting together a multichannel stepped frequency CW radar breadboard, and I'm looking for something to serve as a source that I can step quickly. I'm looking at stepping every millisecond or so. Right now, I use a Ardunino type microcontroller driving a serial DAC driving a

Re: [time-nuts] fast switching quiet synthesizer

2014-10-07 Thread Jim Lux
On 10/7/14, 10:28 AM, Poul-Henning Kamp wrote: In message 54341cbf.9080...@earthlink.net, Jim Lux writes: Maybe some DDS in a box product? That will take my nice clean 10 MHz reference? DDS is by far the easiest, but the question is if it is clean enough. Yes, probably clean

Re: [time-nuts] fast switching quiet synthesizer

2014-10-07 Thread Jim Lux
On 10/7/14, 10:32 AM, Magnus Danielson wrote: You should be able to use DDS test-boards and by timing your last write, you should be able to time the frequency jump. The STEL-1173 takes 6 bytes, but writing the last one latches all 6 bytes over to a single 48 bit word. I expect that other DDSes

Re: [time-nuts] fast switching quiet synthesizer

2014-10-07 Thread Jim Lux
On 10/7/14, 12:43 PM, Anders Wallin wrote: We've been using/testing an AD9912 eval-kit board. It can take 10MHz input and has an internal 66x PLL and VCO for a 660MHz DDS sample-clock (just out of spec actually, vco is min 700MHz if I read the datasheet correctly). Output looks like so:

Re: [time-nuts] fast switching quiet synthesizer

2014-10-07 Thread Jim Lux
On 10/7/14, 1:19 PM, Don Latham wrote: I have two versions of the ADF4351 dds. One is the AD eval board, and the other the TPI synthesizer (http://www.rf-consultant.com/calibrated-signal-generator/) at $280 that might do the job. The latter device performs well. It will be as good as the 4351, I

Re: [time-nuts] fast switching quiet synthesizer

2014-10-07 Thread Jim Lux
On 10/7/14, 4:43 PM, Bob Camp wrote: Hi The output spectrum of some DDS’s is pretty rich. You may find that a 1 GHz DDS can be filtered to operate directly over the 3.1 to 3.4 GHz. Oh, clever idea.. Yes.. there is substantial harmonic content, and one could easily arrange to have more. And

Re: [time-nuts] fast switching quiet synthesizer

2014-10-07 Thread Jim Lux
On 10/7/14, 2:26 PM, Poul-Henning Kamp wrote: In message 20141007200046.02aa9406...@ip-64-139-1-69.sjc.megapath.net, Hal Mu rray writes: Timing on Ethernet is as good as RS-232 if you have a point to point link rather than a huge network full of crappy software. That is a truth with

Re: [time-nuts] What sort of oscillator is this?

2014-09-30 Thread Jim Lux
On 9/30/14, 12:44 AM, REEVES Paul wrote: David, Just a thought but have you tried Pasternack? They do 'custom' precision cabling including 2.4mm connector options. regards, Paul, G8GJA Rather than Pasternack, you might find the following sources useful Citrus Cables does nice quality,

Re: [time-nuts] What sort of oscillator is this?

2014-09-30 Thread Jim Lux
On 9/30/14, 4:56 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 30 Sep 2014 14:16, Jim Lux jim...@earthlink.net wrote: On 9/30/14, 12:44 AM, REEVES Paul wrote: David, Just a thought but have you tried Pasternack? They do 'custom' precision cabling including 2.4mm connector options

Re: [time-nuts] Homemade GPS Receiver

2014-09-29 Thread Jim Lux
On 9/28/14, 10:09 PM, Peter Monta wrote: How hard is the beam steering relative to everything else? It's a weighted sum of the antenna signals (as with any phased array), so the cost is the extra arithmetic to do this (on a per-satellite basis). The weights can be computed open-loop from the

Re: [time-nuts] WWVB d-psk-r down conversion method...

2014-09-23 Thread Jim Lux
On 9/23/14, 10:11 AM, Alexander Pummer wrote: there is an interesting side effect with that phase modulation: in case the crystal filter is narrow enough --to use for the old AM format-- the phase change creates an additional AM modulation, if you take in consideration that effect by the

Re: [time-nuts] NAA experiments as a reference

2014-09-14 Thread Jim Lux
a far wide shift then the baud. What you say would match what the tracor book says and the system is designed for. I still do not see why if I offset the LO to -150 hz I get a useful display to judge timing. I am using the lissajous method. Regards Paul WB8TSL On Sat, Sep 13, 2014 at 11:25 PM, Jim

Re: [time-nuts] NAA experiments as a reference

2014-09-13 Thread Jim Lux
On 9/13/14, 7:33 AM, paul swed wrote: Charles I literally just sat down to do some math. What you say is the same thoughts I have. The information I have on NAA says that for 200bit msk its a total of a 100 hz shift +/-50 Hz. That makes no sense I would think it would be at least +/- 100 Hz.

Re: [time-nuts] NAA experiments as a reference

2014-09-13 Thread Jim Lux
On 9/13/14, 7:13 PM, paul swed wrote: If NAA is transmitting 200 baud then I would expect the MSK carrier to be +/- 100 Hz. Not +/-50 Hz. I'd expect the total shift to be half the baud rate: 100 Hz.. ___ time-nuts mailing list --

Re: [time-nuts] FYI: NPLTime® - a new service providing a precise time signal directly traceable to Coordinated Universal Time (UTC) and independent of GPS.

2014-08-14 Thread Jim Lux
On 8/14/14, 11:12 AM, mike cook wrote: WOW! Guaranteeing compliance with FINRA OATS 7430 ! Here it is.. All computer system clocks and mechanical time stamping devices must be synchronized to within three seconds of the National Institute of Standards and Technology (NIST) atomic

Re: [time-nuts] WWVB for Time Nuts

2014-08-10 Thread Jim Lux
On 8/10/14, 5:41 AM, Bob Camp wrote: Hi Keep in mind that it’s relatively cheap (big company wise) to get a patent. It’s only got major value once the courts uphold it as valid. That process costs real money. I’ve seen a variety of estimates on how many patents get issued that would never

Re: [time-nuts] WWVB for Time Nuts

2014-08-10 Thread Jim Lux
On 8/10/14, 8:30 AM, Bob Camp wrote: Hi …. which also eliminates a full examination and challenge. Bottom line as I still see it - For Time Nuts one off / home use / zero profit/ personal experimentation, I would not worry about the patents that are or are not present on the

Re: [time-nuts] VLF Phase-tracking receivers.

2014-08-10 Thread Jim Lux
On 8/10/14, 9:26 AM, Kenneth G. Gordon wrote: On 10 Aug 2014 at 6:24, paul swed wrote: Hello again, Paul. Thanks for replying. Please see below. On iPhone Yes but those stations are fsk so the offsets an issue. As I understand it from back in the 1970s when I was first working on this sort

Re: [time-nuts] VLF Phase-tracking receivers.

2014-08-10 Thread Jim Lux
On 8/10/14, 11:54 AM, Mike Feher wrote: Unless on what you were working on it had a different meaning, MSK means Minimal Shift Keying. It is still a PSK modulation of any order, however the transition between significant phase locations is not instantaneous, but, shaped in various ways to smooth

[time-nuts] GPS multipath

2014-08-09 Thread Jim Lux
Clarifying my previous question.. There's no doubt that multipath exists, and how to test is fairly straightforward, whether with multiple antennas, cables, or waving cookie sheets around.. What I was really asking is if anyone had observed this in the output of their GPS receiver. That

Re: [time-nuts] GPS multipath

2014-08-09 Thread Jim Lux
On 8/9/14, 9:33 AM, Magnus Danielson wrote: Jim, On 08/09/2014 05:31 PM, Jim Lux wrote: Clarifying my previous question.. There's no doubt that multipath exists, and how to test is fairly straightforward, whether with multiple antennas, cables, or waving cookie sheets around.. Ultimately

Re: [time-nuts] WWVB for Time Nuts

2014-08-09 Thread Jim Lux
On 8/9/14, 10:49 AM, Brooke Clarke wrote: Hi: I've been reading papers by Yingsi Liang who works for Xtendwave and she seems to be the key person developing the new clocks. I've starting collecting info on my web page: http://www.prc68.com/I/Loop.shtml#PhaseMod I don't understand how Xtendwave

Re: [time-nuts] WWVB for Time Nuts

2014-08-09 Thread Jim Lux
On 8/9/14, 12:56 PM, Bob Camp wrote: Hi Keep in mind that the patent(s) do not keep you from building a part for your own use. AS I understand it, this is not technically true. You can practice the patent to gain an understanding of it for the purposes of inventing something new that is

Re: [time-nuts] WWVB for Time Nuts

2014-08-09 Thread Jim Lux
On 8/9/14, 3:49 PM, Bob Camp wrote: Hi That’s not the way it was presented to me. My understanding is that the case law on proving “individual study” versus “individual use” is a bit murky. I’m certainly no lawyer (thank goodness ..). murky is a good way to describe it...

Re: [time-nuts] WWVB for Time Nuts

2014-08-09 Thread Jim Lux
On 8/9/14, 12:27 PM, John Seamons wrote: On Aug 10, 2014, at 5:49 AM, Brooke Clarke bro...@pacific.net wrote: I don't understand how Xtendwave can get patents when their work was partially funded by NIST? We had this discussion a few years back:

Re: [time-nuts] WWVB for Time Nuts

2014-08-09 Thread Jim Lux
On 8/9/14, 9:36 PM, Lee Mushel wrote: Jeeze, Brooke, I wish you hadn't brought up the possible patenting of Time Delay Beam steering antennas! I wonder if my highly esteemed SDR radio which I think uses some such technology, is illegal? long since expired.. (but, I gotta say that a lot of

[time-nuts] multipath on GPS

2014-08-08 Thread Jim Lux
Does anyone have a feel for what the minimum size reflector at some small distance would be detectable on a GPS timing receiver? WOuld you be able to see a change of a 1 meter square reflector 10 meters away? ___ time-nuts mailing list --

Re: [time-nuts] Boeing 787 GPS reception trouble

2014-06-03 Thread Jim Lux
On 6/3/14, 5:51 AM, Chuck Harris wrote: nuts wrote: Regarding radiation, I've used my Geiger counter at mile high altitudes in Nevada and never got a count per second, even with the gamma shield not used. You can look at the DOE CEMP stations: 1 Mile high is still on the ground compared

Re: [time-nuts] Boeing 787 GPS reception trouble

2014-06-02 Thread Jim Lux
On 6/2/14, 1:55 AM, Tom Van Baak wrote: Has anyone else noticed this? Or know about this? Please respond only if you have real information. I can speculate as well as anyone; so it's solid technical, RF, EMF, or composite carbon fiber engineering info I'm looking for. I haven't noticed it

Re: [time-nuts] Boeing 787 GPS reception trouble

2014-06-02 Thread Jim Lux
On 6/2/14, 2:27 AM, Poul-Henning Kamp wrote: It would be trivial to add a passive GPS repeater to the plane, but the airtraffic industry has never been happy about people being able to receive navigation signals inside planes, worrying that somebody might try to blow up the plane at some

Re: [time-nuts] Boeing 787 GPS reception trouble

2014-06-02 Thread Jim Lux
On 6/2/14, 7:16 AM, Brian Lloyd wrote: On Mon, Jun 2, 2014 at 8:57 AM, Jim Lux jim...@earthlink.net wrote: O, and since navigation using the ADF and tuning to a AM broadcast station wasn't unusual. Well, it is quite unusual for IFR (instrument flight rules) operation. But VFR pilots would

Re: [time-nuts] New NIST Time Code to Boost Reception for Radio-Controlled Clocks

2014-05-31 Thread Jim Lux
On 5/31/14, 5:48 PM, Bob Camp wrote: Hi A thousand chips at $1 a chip is a very different thing than a thousand chips at $100 a chip. The next issue might be that they only have them in die form. The issue after that probably is that you really want the version 3 (or 9) chips that actually

Re: [time-nuts] New tide gauge uses GPS signals to measure sea level change

2014-05-30 Thread Jim Lux
On 5/30/14, 2:41 AM, Dr. David Kirkby wrote: On 28 May 2014 14:06, Tom Holmes thol...@woh.rr.com wrote: Which begs the question: just where the heck, exactly, is the center of the Earth given that it is in the 'middle' of a molten and dynamic core. I always thought that the centre was

Re: [time-nuts] New tide gauge uses GPS signals to measure sea level change

2014-05-30 Thread Jim Lux
On 5/30/14, 3:00 PM, Hal Murray wrote: [Structure of Earth's core] jim...@earthlink.net said: Molten, but it's a composite material under a lot of pressure, so the transition between liquid and solid isn't like between ice and water. Think cold peanut butter. Seismic evidence is how they

Re: [time-nuts] New tide gauge uses GPS signals to measure sea level change

2014-05-28 Thread Jim Lux
On 5/28/14, 6:04 AM, Tom Holmes wrote: Which begs the question: just where the heck, exactly, is the center of the Earth given that it is in the 'middle' of a molten and dynamic core. Are the satellite orbits so stable and/or measurable around the center of gravitational pull that the location

Re: [time-nuts] New tide gauge uses GPS signals to measure sea level change

2014-05-28 Thread Jim Lux
On 5/27/14, 9:21 PM, Chris Albertson wrote: On 5/27/14, 10:24 AM, Brooke Clarke wrote: BACK ON TOPIC... What does it take to measure ones distance from the center of the Earth accurately enough to detect geological movement in a reasonable amount of time? Measuring distance really is,

Re: [time-nuts] New tide gauge uses GPS signals to measure sea level change

2014-05-28 Thread Jim Lux
On 5/28/14, 2:11 PM, Tom Holmes wrote: Thanks Jim. So if, just for fun since this is time-nuts after all, I wanted to make a similar measurement in my back yard here in the relatively stable Ohio, would I be able rig something up to monitor the position changes? Obviously a lot of averaging of

Re: [time-nuts] New tide gauge uses GPS signals to measure sea level change

2014-05-27 Thread Jim Lux
On 5/27/14, 10:24 AM, Brooke Clarke wrote: Hi: Classical tide gauges measure the height of the water relative to the gauge. But since the gauge is attached to a tectonic plate it's elevation is changing. This is one of the problems I have with the claim that sea level is rising at 2mm per

[time-nuts] time messages

2014-05-26 Thread Jim Lux
I'm in the middle of implementing a lightweight time distribution system using SpaceWire (a fast point to point serial link with simple routers to build networks). SpaceWire provides a special token called a timecode which propagates from a tick source to various nodes, but that just provides

Re: [time-nuts] time messages

2014-05-26 Thread Jim Lux
On 5/26/14, 11:13 AM, Magnus Danielson wrote: Hi Jim, On 05/26/2014 07:43 PM, Jim Lux wrote: I'm in the middle of implementing a lightweight time distribution system using SpaceWire (a fast point to point serial link with simple routers to build networks). SpaceWire provides a special token

Re: [time-nuts] Low cost GPS module for 100ns timestamping error

2014-05-04 Thread Jim Lux
On 5/2/14, 7:07 PM, Tony wrote: On 03/05/2014 02:07, Edesio Costa e Silva wrote: Welcome! Take a look at NavSpark from SkyTraq (http://www.skytraq.com.tw/). They had an Indiegogo (https://www.indiegogo.com/projects/navspark-arduino-compatible-with-gps-gnss-receiver) campaign recently and

Re: [time-nuts] Low cost GPS module for 100ns timestamping error

2014-05-04 Thread Jim Lux
On 5/4/14, 8:40 AM, Chris Albertson wrote: Looks like this is all you'd need for most timing projects. Just add your favorite OCXO and some wire. The SPARC (not Spark) is actually a step up from ARM. It was developed by Sun Microsystems (now Oracle) it is optimized for things like fast

Re: [time-nuts] Low cost GPS module for 100ns timestamping error

2014-05-04 Thread Jim Lux
On 5/4/14, 10:07 AM, Bob Camp wrote: Hi Well some of us still have RSX-11M (and RSTS/E) code floating around ….. B As do I, but the stuff I'd actually reuse is pretty OS independent (signal processing code in FORTRAN, and in reality, I'd most likely rewrite it anyway.) I suspect you'll

Re: [time-nuts] Low cost GPS module for 100ns timestamping error

2014-05-04 Thread Jim Lux
On 5/4/14, 11:38 AM, Chris Albertson wrote: These guys claim IEEE-754 FPU. But this is not the board to use for a Posix-like OS. For that you'd want disk controller, networking and so on. Ah, so they did include the FPU: that's handy. Actually, an in-ram file system, along with a decent

Re: [time-nuts] Low cost GPS module for 100ns timestamping error

2014-05-04 Thread Jim Lux
On 5/4/14, 11:44 AM, Bob Camp wrote: Hi Well I do have those Sparc machines sitting over in the shed ….. I suspect hauling over the CRT monitor to go with it would be a bit of a pain. I doubt I would win the “low power GPSDO of the year” award with it. Like it or not, once you get to 64

Re: [time-nuts] Symmetricom chip scale atomic clock

2014-04-25 Thread Jim Lux
On 4/24/14, 11:14 PM, Attila Kinali wrote: On Fri, 25 Apr 2014 08:33:06 +0300 MailLists li...@medesign.ro wrote: The recently acquired cash cow isn't working exactly as expected/advertised. We still don't have a clue when/if the fundamental (as in physics laws) design (we can't officially

Re: [time-nuts] Symmetricom chip scale atomic clock

2014-04-25 Thread Jim Lux
On 4/24/14, 11:43 PM, Magnus Danielson wrote: Jim, On 04/25/2014 05:32 AM, Jim Lux wrote: On 4/24/14, 6:26 PM, Said Jackson wrote: Hi Magnus, Bob, Thanks much for your kind words. The failure rate is thankfully so low that we are not greatly alarmed, and Microsemi has been a champ

Re: [time-nuts] Symmetricom chip scale atomic clock

2014-04-24 Thread Jim Lux
On 4/24/14, 6:26 PM, Said Jackson wrote: Hi Magnus, Bob, Thanks much for your kind words. The failure rate is thankfully so low that we are not greatly alarmed, and Microsemi has been a champ in resolving any failures with/for us when they did show up. We are awaiting the results of the full

Re: [time-nuts] GPS antenna in silicon/RTV encapsulation

2014-04-18 Thread Jim Lux
On 4/17/14, 11:09 AM, Lester Veenstra wrote: The classic DIY test of material for RF use is give it 60 seconds in a microwave oven. If it gets warm, it’s not a good candidate. that's fine if you're looking for a gross measure of suitability. If you're concerned about things like dielectric

Re: [time-nuts] GPS antenna in silicon/RTV encapsulation

2014-04-16 Thread Jim Lux
On 4/15/14, 8:16 PM, nuts wrote: I don't use the surf board resin. I use http://www.tapplastics.com/product/fiberglass/polyester_resins/tap_marine_vinyl_ester_resin/34 I don't have specifics on what Tap sells, but vinyl ester resins have a dielectic coeficient around 4 and dissipation of at

Re: [time-nuts] GPS antenna in silicon/RTV encapsulation

2014-04-15 Thread Jim Lux
On 4/15/14, 1:53 AM, nuts wrote: I'd be inclined to look at radome construction. http://www.mpdigest.com/issue/articles/2008/may/mfg/default.asp The E-3 AWACS is mostly S-2 glass, but they need the strength. For a radome sitting outside, you might be able to do better. Radome design is

Re: [time-nuts] GPS antenna in silicon/RTV encapsulation

2014-04-15 Thread Jim Lux
On 4/15/14, 8:13 AM, ewkeh...@aol.com wrote: Working off list on a super high performance GPSDO but low cost thanks to a time nut (sorry forgot his name) he directed me to DX.com which have ublox with antenna for lwss than $ 23. Super performance and though they are out of the one with 1 pps

Re: [time-nuts] GPS antenna in silicon/RTV encapsulation

2014-04-15 Thread Jim Lux
On 4/15/14, 11:02 AM, ewkeh...@aol.com wrote: The Gerber Baby Food Jar at Wall Mart $ 0.49 Is there a particular kind of food that works best? Perhaps strained prunes has the best regularity? ___ time-nuts mailing list -- time-nuts@febo.com To

Re: [time-nuts] GPS antenna in silicon/RTV encapsulation

2014-04-14 Thread Jim Lux
On 4/14/14, 12:11 PM, ewkeh...@aol.com wrote: Am experimenting with small low cost GPS antennas and am considering as an alternative RTV/silicon. Any information on RF attenuation of RTV/silicon at 1.6 GHz ? Are you potting the antenna in a solid mass of silicone? Or using it to seal an

Re: [time-nuts] ARM boards for low-cost GPSDOs

2014-04-12 Thread Jim Lux
On 4/12/14, 12:50 PM, Bob Camp wrote: Hi I’ve been working with some friends on an ARM based Arduino project. The support for ARM in the Arduino tool chain is still not really up to speed. It’s actually been faster / easier to take the stuff we need over to another board and tool chain than

Re: [time-nuts] ARM boards for low-cost GPSDOs

2014-04-10 Thread Jim Lux
On 4/10/14 2:38 PM, Hal Murray wrote: Does anybody have a favorite low-cost ARM board? I'm looking for a simple Arduino like setup rather than something that runs Linux. The idea is to get 32 bit counters so a bunch of the recent discussion can be ingnored. teensy3.1.. ARM Cortex M0 in the

Re: [time-nuts] Water on Enceladus - What does this imply about NASA'a ability to measure frequency?

2014-04-04 Thread Jim Lux
On 4/3/14 8:17 PM, Chris Albertson wrote: I just read about a discovery of a liquid water ocean on Saturn's moon Enceladus. The method used was to measure the velocity of a spacecraft as it makes a close fly-by. Gravitational anomalies will cause the spacecraft to speed up or slow down as it

Re: [time-nuts] Water on Enceladus - What does this imply about NASA'a ability to measure frequency?

2014-04-04 Thread Jim Lux
On 4/3/14 11:17 PM, Chuck Forsberg WA7KGX wrote: One needs to know the carrier frequency. Must be a high quality reference for the Cassini transmitter. Two way measurements are most likely here (although Cassini does carry a USO). So the downlink is locked to the uplink which comes from a

Re: [time-nuts] Water on Enceladus - What does this imply about NASA'a ability to measure frequency?

2014-04-04 Thread Jim Lux
On 4/4/14 4:30 AM, Bob Camp wrote: Hi Back when they were designing this stuff, they were very interested in getting into the parts in 10 to the 15th. They didn’t get there, but that was the desire. Roughly that... http://lasp.colorado.edu/~horanyi/graduate_seminar/RSS.pdf is a good

Re: [time-nuts] Water on Enceladus - What does this imply about NASA'a ability to measure frequency?

2014-04-04 Thread Jim Lux
On 4/4/14 7:39 AM, Bill Hawkins wrote: Jim, Thanks for sharing the details and preventing this subject from turning into shared ignorance. It was working on this kind of thing that led me to time-nuts in the first place.. Deep Space nav is probably one of the most precise measurements made

Re: [time-nuts] Water on Enceladus - What does this imply about NASA'a ability to measure frequency?

2014-04-04 Thread Jim Lux
On 4/4/14 5:01 AM, Dr. David Kirkby wrote: On 4 Apr 2014 08:55, Tom Knox act...@hotmail.com wrote: 90 microns is approx a freq res of about 1 x 3.66 -12 Thomas Knox Since the Doppler shift is prortional to the frequency, I can't see how one can determine the absolute frequency. But

Re: [time-nuts] Water on Enceladus - What does this imply about NASA'a ability to measure frequency?

2014-04-04 Thread Jim Lux
On 4/4/14 9:34 AM, Chris Albertson wrote: On Fri, Apr 4, 2014 at 6:19 AM, Jim Lux jim...@earthlink.net wrote: Radio science and navigation measurements are quite impressive in their accuracy and attention to detail. measuring range to cm (out of a billion km, i.e 1 part in 1E14) and velocity

Re: [time-nuts] Water on Enceladus - What does this imply about NASA'a ability to measure frequency?

2014-04-04 Thread Jim Lux
On 4/4/14 9:58 AM, Alex Pummer wrote: gravitation measurement, particularly gravitation measurement in space is based on the Eotvos -effect see here: http://en.wikipedia.org/wiki/E%C3%B6tv%C3%B6s_effect and here: http://en.wikipedia.org/wiki/Lor%C3%A1nd_E%C3%B6tv%C3%B6sand from the begin

Re: [time-nuts] M12+T module questions

2014-04-04 Thread Jim Lux
On 4/4/14 6:51 PM, Chris Albertson wrote: The data connector is a standard 0.05 inch double row of male headers. These are common but not nearly so common as the 0.1 type. I used a 2032 coin cell battery and holder I un-soldered from an dead PC motherboard. Even a coin cell will last its shelf

Re: [time-nuts] new GPSDO kit

2014-04-04 Thread Jim Lux
On 4/4/14 5:45 PM, paul swed wrote: I mean no disrespect to anyone here. Jacksonlabs makes some very fine components. Brookes comment was spot on. What happens etc. I did run out to the site and take a quick read. The short piece I read did not have a lot of specifics or I simply missed them. It

[time-nuts] GPS-18x behaving weirdly

2014-03-27 Thread Jim Lux
I've got some GPS-18x LVC units i'm using for a time reference, and they're showing an odd behavior: the position isn't updating. I moved them across the US (from Los Angeles to the east coast), and when I powered them up here, it's returning the LA Lat/Lon (34N,118W), the (reasonably

Re: [time-nuts] GPS-18x behaving weirdly

2014-03-27 Thread Jim Lux
On 3/27/14 8:53 AM, David J Taylor wrote: From: Jim Lux [] Has anyone seen a similar behavior? I've tried the power cycling, and the Garmin reset command. I've not done the clear non-volatile memory which makes it forget the almanac. === What

Re: [time-nuts] FEI-5660 Rubidium Oscillator

2014-03-27 Thread Jim Lux
On 3/27/14 4:10 PM, Tom Van Baak wrote: Recently I happened across an eBay listing for an Antelope Audio Isochrome, a device that apparently packages an SRI-PRS10 rubidium oscillator and distribution amplifier in a box and sells to audiophiles for a price in the True, the PRS10 is a better

Re: [time-nuts] Airraft Ping Timing

2014-03-25 Thread Jim Lux
On 3/24/14 10:18 PM, David McGaw wrote: I am surprised it took them this long. A number of satellite telemetry systems can use doppler as a matter of course for locating transmitters, such as Iridium and Argos. Those are actually designed for measuring Doppler.. That's really the difference..

Re: [time-nuts] Airraft Ping Timing

2014-03-25 Thread Jim Lux
On 3/25/14 11:38 AM, J. Forster wrote: Could well be. I never saw the bird, of course. The portable ground station was roughly the same size as an OD Manpak radio of the period and read out Lat/Long on LED digital readouts. In retrospect, it may have been in the early 1980s. Transit,

Re: [time-nuts] NIST time services

2014-03-24 Thread Jim Lux
On 3/23/14 10:48 AM, Paul wrote: On Sun, Mar 23, 2014 at 1:08 PM, Bob Camp li...@rtty.us wrote: I suspect that what NIST is looking for is somebody in the cloud business (Amazon, Google, Microsoft, IBM) to step up and mention that they have 2,989,875 server racks scattered about the world and

Re: [time-nuts] Airraft Ping Timing

2014-03-24 Thread Jim Lux
On 3/24/14 6:15 PM, Chris Albertson wrote: Yes, word is that they were able to determine the Doppler shift in the plane's signal. I'm surprised this was even recorded but it must have been in the satellite's telemetry downlink. Projecting radial velocity and constraining it to be close to the

Re: [time-nuts] Aircraft ping timing

2014-03-22 Thread Jim Lux
On 3/21/14 8:52 PM, nuts wrote: On Thu, 20 Mar 2014 14:42:42 -0400 Joe Leikhim jleik...@leikhim.com wrote: I just red somewhere that the last ping was the only one recorded by Inmarsat system, Pings up to that point were presumed to occur due to known reporting intervals. So there is no track.

Re: [time-nuts] NIST time services

2014-03-22 Thread Jim Lux
On 3/19/14 9:50 AM, Chris Albertson wrote: So they want to in-invent NTP? I think NTP already services way more than 6.5 billion per day. The problem with NTP is while it is nearly optimal and provides the best time accuracy for a given hardware/network setup it is not technically traceable

Re: [time-nuts] Aircraft ping timing

2014-03-20 Thread Jim Lux
On 3/20/14 12:07 AM, Poul-Henning Kamp wrote: In message 279331507.5734621395275538874.JavaMail.actor@webmail5, iovane@inw ind.it writes: My question was on what would be the expected accuracy of the circle's radius. Projected onto the surface of the earth, the uncertainty leaves a band

Re: [time-nuts] Aircraft ping timing

2014-03-20 Thread Jim Lux
On 3/20/14 8:53 AM, Poul-Henning Kamp wrote: In message 40280C39FE7D43C79313A1755BCAF58D@StanleyPC, Stanley writes: Would think they have many other aircraft with known position stationary or moving with location known to help improve the estimate. They might have been able to do that while

Re: [time-nuts] NIST time services

2014-03-19 Thread Jim Lux
On 3/18/14 10:18 PM, Tom Van Baak wrote: If you can design a system that can handle 6.5 billion requests per day, this opportunity is for you... https://www.fbo.gov/spg/DOC/NIST/AcAsD/RFI_InternetTimeServiceComments/listing.html Solicitation Number: RFI_InternetTimeServiceComments For

[time-nuts] Fwd: Re: NIST time services

2014-03-19 Thread Jim Lux
Original Message Subject: Re: [time-nuts] NIST time services Date: Wed, 19 Mar 2014 10:21:17 -0700 From: Jim Lux jim...@earthlink.net To: time-nuts@febo.com On 3/19/14 9:50 AM, Chris Albertson wrote: So they want to in-invent NTP? I think NTP already services way more than

Re: [time-nuts] Aircraft ping timing

2014-03-19 Thread Jim Lux
On 3/19/14 5:21 PM, Bill Hawkins wrote: They only got one ping from INMARSAT at 64E above the Indian Ocean. There was no other ping to triangulate the position. One ping projects a circle on the Earth. The maximum flying range of the plane determined the ends of the NE and SE arcs of that

Re: [time-nuts] Power Supply for AD9852 / AD9854

2014-03-16 Thread Jim Lux
On 3/16/14 8:13 AM, d0ct0r wrote: Thanks ! Looks like I am on the right track. I've attached couple of documents which could be useful. I'am going to use two separated voltage regulators for VCC/AVDD and DVDD. And use 10 Ohm / 100Mhz ferrite board and few capacitors to separate VCC and AVDD.

Re: [time-nuts] Power Supply for AD9852 / AD9854

2014-03-16 Thread Jim Lux
On 3/16/14 9:34 AM, d0ct0r wrote: I would assume that using two voltage regulators will spread the load. For the AD9851 I'am planning to put external radiator glued on top of it. It's not the power dissipation of the regulators that's the concern, it's the dissipation of the 9854. A

Re: [time-nuts] PLL Math Question

2014-03-13 Thread Jim Lux
On 3/12/14 10:06 PM, Chris Albertson wrote: On Wed, Mar 12, 2014 at 9:13 PM, Daniel Mendes dmend...@gmail.com wrote: This is a FIR x IIR question... moving average = FIR filter with all N coeficients equalling 1/N exponential average = using a simple rule to make an IIR filter Isn't his

Re: [time-nuts] Another atomic clock question

2014-03-07 Thread Jim Lux
On 3/7/14 12:31 PM, Chris Albertson wrote: On Fri, Mar 7, 2014 at 10:28 AM, Lars Walenius lars.walen...@hotmail.com wrote: Chris, about using one Arduino for two GPSDO controllers: Even if a microcontroller has lots of capacity I would recommend to use separate controllers for each

Re: [time-nuts] Another atomic clock question

2014-03-07 Thread Jim Lux
On 3/7/14 3:33 PM, Chris Albertson wrote: Let's see what is needed. The ADC is 10-bits so it can read to one part in 1024. It's a 5 volt full scale so we are only able to measure 5 millivolt increments if you use the teensy3 it has a 16 bit ADC with realistically, about 13 bits

Re: [time-nuts] Another atomic clock question

2014-03-03 Thread Jim Lux
On 3/3/14 2:18 AM, Hal Murray wrote: Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C albertson.ch...@gmail.com said: So does this mean I can epoxy a sandstone power resister to a junk crystal and keep the frequency exactly perfect by varying the power in the resister?

Re: [time-nuts] FSCM 38243 Power Distribution Module

2014-03-02 Thread Jim Lux
On 3/2/14 8:32 AM, Glen Hoag wrote: FSCM 38243 is the manufacturer information. FSCM is the Federal Supply Code for Manufacturers, which appears to be a subset of CAGE (Commercial and Government Entity) codes maintained by the Defense Logistics Agency. FSCM 38243 appears to be PG Electronics

Re: [time-nuts] Another atomic clock question

2014-03-02 Thread Jim Lux
On 3/2/14 11:09 AM, Chris Albertson wrote: Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C So does this mean I can epoxy a sandstone power resister to a junk crystal and keep the frequency exactly perfect by varying the power in the resister? Yes.. but you have to hold

<    1   2   3   4   5   6   7   8   9   10   >