Re: [time-nuts] Google public NTP service
On 11/30/2016 3:35 PM, Gary E. Miller wrote: > Not true. NTP has provision for arbitrrary extensions to an ntp packet. > > See RFC 5905. https://www.ietf.org/rfc/rfc5905.txt section 7.3: HA! ntp (the implementation) doesn't follow the RFC, which says that ntp (the protocol) is supposed to count seconds in an epoch. It doesn't, it deliberately miscounts when there's a leap second. Instead of simply counting seconds like TAI, it's broken just like POSIX. ___ 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] Seiko watch "leap second enabled"
On 7/21/2016 12:09 AM, Mike Cook wrote: > « Seiko Astron enters the leap second data receiving mode after the > first GPS signal is received on or after June 1st and December 1st. » > (User Manual) Why 6/1 and 12/1? Leap seconds can happen any month. June and December are only a preference. Sounds like the world's first fundamentally flawed "leap second enabled" watch. ___ 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] patents and hobbyist projects
On 5/14/2016 5:56 AM, Attila Kinali wrote: > For one, patents are about > commercial use only. If you don't sell it, patents don't apply > (this is a bit simplified, but not incorrect). Not sure where you are, but it's definitely incorrect for the US, where mere use, let alone making, can be infringing. Whether an individual would actually be sued for a hobby use is a different matter, but it could happen: 35 U.S.C. 271 Infringement of patent. (a) Except as otherwise provided in this title, whoever without authority makes, uses, offers to sell, or sells any patented invention, within the United States, or imports into the United States any patented invention during the term of the patent therefor, infringes the patent. ___ 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] Cheap 5370A on eBay
On 12/19/2014 10:40 PM, Mark Sims wrote: I few years back i posted on this forum how I restored a 5370A that had a missing ROM board by installing an EEPROM into the empty socket on the CPU board. Based off of that, I did similar, and documented it here: http://www.flatsurface.com/5370A/ ___ 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] NPR Story I heard this morning
On 11/3/2014 3:54 PM, Tom Van Baak wrote: When it comes to frequency standards the official SI second is defined only for sea level. We know time and frequency are bent by speed or gravity; According to the BIPM: At its 1997 meeting the CIPM affirmed that: This definition refers to a caesium atom at rest at a temperature of 0 K. - http://www.bipm.org/en/publications/si-brochure/second.html Isn't weight equivalent to acceleration, and it's therefore not at rest when sitting on a table at sea level? I don't see anything in the BIPM definition of the second regarding sea level. ___ 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] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812A GPSDO system (Bob Camp)
On 10/31/2014 6:14 PM, Bob Camp wrote: check a DB-9-M and DB-9-F ITYM DE-9-P and DE-9-S. Sorry, it's a pet peeve. 'taint no such thing as a DB-9, and the gender is Pin or Socket because male and female are ambiguous given the physical construction. ___ 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] Z38xx rack mounts
On 10/22/2014 4:44 PM, Dave M wrote: The Z38xx units are 11 wide (10-9/16 mounting centers) , and obviously are not suitable for a standard 19 rack cabinet. The Nortel GPSR (aka HP z3801a) was mounted vertically in a chassis which was itself rack mounted. It's 11 tall, not wide. ___ 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] 5370 processor boards available
On 10/8/2014 8:46 AM, Chuck Harris wrote: Other than turning the 5370A into a capable replacement for the 5370B... ? I believe the only significant difference between the A and B is that the B had a slightly more robust input module, and came standard with the 10811 OCXO. There were some firmware differences related to GPIB handling, but the B firmware works in the A. I posted instructions a while back - http://www.flatsurface.com/5370A/ ___ 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] 5370 processor boards available
On 10/8/2014 9:52 AM, Chuck Harris wrote: The B is significantly faster in handling the GPIB interface, and other internal processor functions than the A... Why would that be? They use the same speed processor, and the GPIB interface is unchanged. ___ 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] Correcting jitter on the 1 PPSsignalfromaGPSreceiver.
On 9/15/2014 10:01 AM, Tom Miller wrote: Fast risetime pulses _are_ RF and need to be treated as such. You say that as if simply saying it provides an explanation, or even a reason. Exactly what ill effect on a triggered measurement is there if one does not terminate a PPS signal properly? Does/can termination increase the slew rate or make the speed of propagation more consistent, which might make the measurement more accurate? Like Tom said, what comes after the leading edge of a PPS signal (which is the measurement trigger) seems irrelevant. A simple though experiment. If I take a high impedance measurement at a tap 1M from the source, and the cable ends another 100M away, how can the termination or lack thereof at that end effect my measurement of a single event? It's over 700 ns round trip away? If I repeat that event 1/sec, is it any different? I can see where there would be a difference when I get close to a 700 ns cycle time, and likely before because of ringing. But for a 1 second cycle? Someone will have to provide more than a dismissive just because to convince me. ___ 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] Correcting jitter on the 1 PPSsignalfromaGPSreceiver.
On 9/15/2014 3:04 PM, Tom Miller wrote: So does adding ~80 pF per meter or 8 nF for 100 meters (RG58) to your output have any effect on the risetime? Because that is what it will see with an open cable. It's not nearly that simple. 8 nF distributed along 100 M is not the same as an 8 nF cap at the source. The example I gave was measuring 1 M from the source, then 100 M of cable beyond that. If the signal has a rise time of, say, 20 ns (Thunderbolt max spec), then anything added cable of more than 3 M (~ 10 ns one way) simply doesn't matter - there's no time for anything which happens to the signal beyond that distance to return in less than the rise time. The signal during the rise time can't know whether there's 3 M or 1000 M of additional cable, or whether the far end is terminated or not. I don't pretend to fully understand transmission lines, but I do know the basics. ___ 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] GPS antenna in snowy environment
On 8/28/2014 2:15 PM, Attila Kinali wrote: On Thu, 28 Aug 2014 12:00:19 -0400 Dan Kemppainen d...@irtelemetrics.com wrote: However, that raises a good questions, in terms of cones and shedding snow. I wonder how a straight slender vertical pipe with capped end ... But the pipe is not such a good idea. All signals from high elevation angle will have a long path trough the pipe, changing their phase ever so slightly. Use a PVC pipe. ___ 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] Time in Phone System
On 7/21/2014 11:07 PM, Brooke Clarke wrote: Every phone in my house that has an LCD shows the correct date time, but I have never set any of them. I expect that there's date and time information being sent in the header of every phone call, maybe even before the first ring along with the Caller ID info CID is sent using FSK between the first and second rings, and includes the networks idea of TOD. Google can provide details. ___ 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] Synergy-GPS SSR-6tru problems
On 7/15/2014 6:58 PM, Art Sepin wrote: A firmware update including the 8 channel @@Ea message (like the UT+) will be available in the coming months. A 6 channel @@Ba command is also being added so that users of legacy HP timing products that used the old VP Oncore will have an up-grade path. Hope this helps. There are also a bunch of @@C* and @@A* commands (and more) which the HP Z3801A uses. Is that one of the intended targets? ___ 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] 5370 processor boards available
On 2/27/2014 6:38 AM, Poul-Henning Kamp wrote: They generally don't mount their filesystems read/write, but only read/only. I've done similar things with FreeBSD in many systems (see: nanobsd) but I don't have time or clue to figure out how to do that with Linux. The way TiVo does this is to have a RO / partition, and a RW /var partition. Normally, any writing is done in /var. If it gets corrupted, it gets rebuilt at boot time. But, they don't have to deal with user account and changing config files (those are stored outside the Linux partitions). But, the concept could be easily extended so perhaps / is only RW during short times when changes which need to be non-volatile are made. (soft link /tmp to somewhere in /var, too) I belive that busybox is somewhat akin to nanobsd, but don't know how to get that onto the BBB hardware. bb is just an all-in-one binary, which provides many standard *nix commands, often in a form just different enough from the gnu coreutils and POSIX specs to screw things up when you're not watching. ___ 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] Looking for WWVB digital wall clock with digital 24 hour UTC display
On 2/19/2014 8:47 PM, Richard (Rick) Karlquist wrote: Thanks for the suggestions, but the MFJ121 does not display the date and the Lacrosse 8055 and 8016 do not display seconds. I need hour minutes seconds day and date. You wouldn't think that would be so hard. It looks like my only choice is this smallish wall clock (more like a desk clock): How about a cheap Android tablet and a clock application? I assume you're planning on AC power, since LEDs won't run long on battery. Sellout.woot.com has a $60 tablet, and it's not hard to find them under $100. According to the manual, If Sero 7 connected with a Wi-Fi, you can also select use network-provided time. While not strictly WWVB, if you only need 1 second resolution, NTP should be fine. This also assumes you have WiFi available. You can probably find a 10 one for $100. If you stretch, I've seen refurb 1st gen iPads for $150 (pretty sure these can do NTP, too). The real cheap tablets tend to have poor digitizers, but that really doesn't matter for use as a wall clock. http://sellout.woot.com http://hisense-usa.com/tablets/sero7lt https://play.google.com/store/apps/details?id=com.gadgetjuice.dockclock ___ 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] Trimble Thunderbolt 1pps
On 1/27/2014 1:33 PM, Robert Atkinson wrote: I looked at this a while ago. The spec only defines transmission levels, it does NOT specify receive thresholds. It certainly does... 2.1.3 For data interchange circuits, the signal shall be considered in the marking condition when the voltage on the interchange circuit, measured at the interface point, is more negative than -3 volts with respect to Circuit AB (Signal Common). The signal shall be considered in the spacing condition when the voltage is more positive than +3 volts with respect to Circuit AB (see 6.2). The region between +- 3 volts is defined as the transition region. The signal state is undefined when the voltage is in this transition region. - ANSI TIA/EIA-232-F (1997) ___ 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] NIST off-line
On 10/1/2013 4:03 PM, Brooke Clarke wrote: The reason for the lack of voting in Washington in relation to any bill that requires a tax raise is because 219 House and 39 Senate members have signed a pledge that says they will not vote for any tax increases, In what way is trying to create political brouhaha compatible with a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics? The problems with all the animosity in US politics is _exactly_ because of people like you. ___ 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] HP5061B Beam Tubes
On 9/23/2013 7:32 AM, Bob Camp wrote: On Sep 23, 2013, at 2:57 AM, cdel...@juno.com wrote: Per the following Symmetricom instructions, HP/Agilent/Symmetricom tubes or instruments with tubes are exempt from the Hazmat requirements if shipped within the USA. You still have to label them per the instructions and as stated you are considered trained If you understand the instructions. http://www.symmetricom.com/media/files/downloads/product-datasheets/shipp ing_instructions.pdf That link does not lead to anything. It works fine, and points to a pdf containing Shipping Instructions for Caesium Devices You do have to put the link back together, since it's longer than the convention for line length. ___ 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] sub-minute time-precision in court-case
On 9/3/2013 10:56 AM, Jim Lux wrote: In this case, all the messages were presumably handled by the same carrier, so the issue of skew in timestamps is negligible; they're all presumably running off the same clock. But not necessarily the same time. For instance, some cell systems run on GPS time, but the carrier may keep records in UTC, since it's the legal time in most jurisdictions. A phone might time stamp using either (Google has a years-old bug in Android which lets it use GPS time and not UTC). So, different devices on the same network may not be in sync. ___ 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] B.V.A. 8600 for sale
On 8/29/2013 9:01 AM, Dr. David Kirkby wrote: On 29 August 2013 01:00, Mann Weltzeit mweltz...@ymail.com wrote: I offer satisfaction protection in private sale at $3000.00 USD for each unit Am I missing something, or is $3000 more than a little excessive for what a quick Google would suggest is an OCXO? Well, considering it was a first post by Mr. Man Worldtime, I'd say it's an opportunist looking for a sucker. ___ 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] PTPv2 grandmaster with a Z3805A?
On 8/20/2013 1:41 PM, Wojciech Owczarek wrote: True, this will help, and needless to say, dynamic CPU frequency etc. is a no-no, On modern x86 processors, both Intel and AMD, the tsc increments at a constant rate, independent of the CPU frequency. ___ 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] GPIB/HPIB Address 31, Talk Only
On 8/7/2013 3:22 PM, stan, W1LE wrote: Is address 31, for talk only, a HP/Agilent feature only, or do tothers provide talk only on the buss ? My understanding is that 31 is illegal as a device address, used to untalk/unlisten all devices. Perhaps what you mention is something from early HPIB (as opposed to newer GPIB/IEEE-488). There are non-HP talk-only devices, but they would use a normal 0-30 device address. But, I could be wrong, I don't pretend to be an expert on 488. ___ 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] Net4501
On 6/5/2013 6:51 PM, Didier Juges wrote: without using the high stability CPU oscillator option, just the PPS from one of my Thunderbolts. Is that even worthwhile? Will the high resolution built-in counters of the Elan processor be useful without the external oscillator compared to a plain vanilla ARM SBC? It may actually be worse. I've got three running with the ELAN timer tweak, but only the standard CPU crystal. Two with Oncore 12+, one with Garmin 18x. All produce loopstat offsets in the 10's of us, very closely linked to temperature. A tbolt feeding a PC keeps the offset much tighter than any of the three, but has much more jitter. One 4501 will do better than the PC if the temperature is fairly stable (slowly changing 3C diurnal change). I think that's because when NTP sees low jitter, it increases the time constant, so it takes much longer to correct for temperature related excursions. I haven't really looked into it further, there may be an NTP tweak which forces a shorter time constant. ___ 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] Net4501
On 6/5/2013 10:33 PM, Hal Murray wrote: mi...@flatsurface.com said: I haven't really looked into it further, there may be an NTP tweak which forces a shorter time constant. minpoll, maxpoll Polling interval is different than update interval. From a FAQ at ntp.org: Recent versions of ntpd (like 4.1.0) seem to update the correction values less frequently, possibly causing problems. Even if the reference time sources are polled more frequently, the local system clock is adjusted less often. There may also be an issue with how much adjustment NTP applies, rather than how often. ___ 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] Net4501
On 6/5/2013 11:14 PM, Chris Albertson wrote: So other than bragging rights what do you get with a picosecond level NTP server? You're posting to the wrong list. :-) ___ 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] Trimble Acutime Gold PPS
On 5/19/2013 5:03 PM, Miguel Barbosa Gonçalves wrote: - Port A (T+) to R+ on the converter - Port A (T-) to R- on the converter - PPS+ to T+ on the converter - PPS- to T- on the converter On the RS232 part of the converter - TXD (pin 3) to computer pin 1 (DCD) - RXD (pin 2)to computer pin 2 (RXD) - GND (pin 5)to computer pin 5 (GND) I can see the serial time code on the computer yet the PPS (a long 400 ms one) doesn't seem to reach the computer. You're trying to have two different signals sourced on the 422 side converted to 232 outputs. That converter is bidirectional, it converts one signal from 422 to 232, and another from 232 to 422. Your PPS signal is going into an output on the converter. ___ 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] GSP clock stabilitiy, Rb vs Cs
On 5/4/2013 2:40 PM, Attila Kinali wrote: Can anyone shed some light on why the GPS Cs beams have a worse stability than the Rb vapor clocks? I don't know, but it makes me wonder about things like 1) How sensitive is each to C-field tuning - i.e. for the same change in C-field, by how much does each type change in relative frequency? (or maybe it's exactly the same, I know nothing about the Zeeman effect) I'd think there would be orbital changes in frequency, after all, it's orbiting a big magnet. 2) How tight a lock can be obtained on each? i.e. might the physical realizations of Rb clocks have a higher Q-factor? ___ 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] S743 Marketplace Fariness Act - the thing that wouldn't die.
Can we admit that this is completely off-topic for this list, and move on to appropriate topics? ___ 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] NIST DSS5 - Info
On 4/23/2013 10:31 AM, cfo wrote: I don't expect NIST to keep the commandset (manuals) a secret , but doesn't have any contacts at NIST. Can you read the ROM(s), and do a strings on them? ___ 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] Z3805A OCXO p/n 3505A09422?
On 4/18/2013 5:41 PM, Brooke Clarke wrote: It has an OCXO that I haven't seen before with a paper sticker with it's p/n: 3505A09422 The A normally means made in America. It's a double oven HP 10811A, you're looking at the serial number sticker. ___ 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] Connectors
On 4/12/2013 1:58 PM, Rick Karlquist wrote: What are you referring to as scotchguard? I thought that was a discontinued waterproofing spray for fabric. You must be talking about something else. He may have meant Scotchkote, as in Scotchkote Electrical Coating FD. BTW, Scotchgard is used for multiple products, and the fabric spray isn't discontinued, just reformulated. ___ 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] Photodiodes for high frequency OPLL
On 3/30/2013 7:48 AM, Attila Kinali wrote: So far, i figured out that PIN photodiodes can go up to several 100MHz transition frequency and avalanche photodiodes are available up to 2GHz. The only photodiodes that go higher are those for the telecom range at 1-1.5um, which is a bit low for my needs. But, i have seen descriptions of such OPLL that work with multi GHz offsets in the 700-800nm range. Maybe you can find something here: http://www.gcsincorp.com/optical_chips/GaAs%20%20InGaAs%20PIN%20Photodetectors.php They have ones which have a wavelength range of 760-860 nm, and go up to 14 GHz. ___ 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] HP53132A vs SR625
On 3/17/2013 1:56 PM, Ed Palmer wrote: On 3/17/2013 10:41 AM, Said Jackson wrote: The acceptable specs are pretty crappy in tim-nuts terms: +/-350pico * frequency with a 1s gate time. Thats straight from the user manual and assuming no reference error. From the manual: Frequency Accuracy: ± ((100ps typ [350 ps max])/Gate + Timebase Error ) x Frequency That equation looks similar in form to the specs for any counter. What are the comparable equations for the 53132A or the 5370(A or B)? 5370B is similar ±Resolution ±(Time Base Error) x FREQ ± (100 ps Systematic/Gate Time) x FREQ ___ 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] Voltage on antennas
On 3/13/2013 7:36 PM, Ed Palmer wrote: You can also put a 5-volt GPS on port 1 to match your 5-volt antenna and GPSs with other voltages, e.g. 3.3 or even 12 volts, on the other ports. This way, you don't lose the use of one port. That's the last thing I'd want to do, literally, since that means that turning off or disconnecting that one GPS takes all the others down. If/when I need the 4th port for GPS, but not until. ___ 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] Voltage on antennas
On 3/13/2013 6:40 PM, lstosk...@cox.net wrote: Some of the little magnetic attached antennas on eBay will operate on 3-5V. More problematic is using the older antennas which require 5V with the newer chips such as the LEA-5,6,7 series which run on 3.3V. Some distribution amps will all you to inject the voltage you need. I have an HP 58516A (an inexpensive eBay purchase) which passes the voltage from port 1 to the antenna. That also powers the amp. So, I put clean 5 V into port 1, and connect GPS receivers to the other 3. ___ 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] Thunderbolt antenna
On 3/10/2013 12:04 PM, Peter Gottlieb wrote: RG-5910.4 dB/100 ft RG-68.4 dB/100 ft Heliax 7.4 dB/100 ft FSJ1-50A RG-11 5.7 dB/100 ft (Yes, I'm aware of the impedance differences) I used LMR-400. 5.1 dB @1.5 GHz /100 ft, 90 dB shield. And, it's 50 ohms. ___ 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] Hello and new Project
On 2/21/2013 10:05 PM, Martin A Flynn wrote: Hi folks, I picked up a used TS-2100L for use at a local technology museum. Unit powers up, locks, and syncs. (all three front panel LED are green) Using wire shark I can see traffic to the device on 192.168.56.99, however I can't connect to the management page. Any suggestions on how to proceed? Obvious questions - Can you ping it? Did you configure your PC to be on the same subnet (192.168.56.0/24)? Have you tried connecting to the serial console? ___ 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] Possibly off topic - Jitter on Ethernet over power adapters
On 2/10/2013 6:04 PM, Magnus Danielson wrote: You should read TCP/IP as Internet Protocols (notice plural form here). It points to the stack of protocols, Actually, no. IP is Internet Protocol, singular, and is the L3 (mostly - IP predates the ISO/OSI model layers, so IP suite protocols don't map exactly) protocol upon which both TCP and UDP are built. It's defined by RFC 791. TCP/IP, simply because those are the most commonly used protocols in the suite. ___ 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] GPS at 60,000 feet
On 1/29/2013 1:55 PM, saidj...@aol.com wrote: Note that this is higher than the older GPS would support, due to the new Wassenaar speed/altitude limits. What are the current limits? UBlox is Swiss, and therefore subject to Wassenaar. Are there any GPS chip makers in China (or ?), who wouldn't be subject to any limitations? ___ 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] Trimble TB PCB board gpsdo question
On 1/25/2013 9:00 AM, Erno Peres wrote: it has a second frequency output 9,830400 MHz. What is the purpose for this freq in the GSM base station... None that I can think of. But it is 8 times the CDMA chip rate of 1.2288 MHz, so would be useful in a CDMA base station. ___ 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] One Kg Quartz Resonator
On 1/23/2013 3:34 AM, Magnus Danielson wrote: On 01/23/2013 02:32 AM, Mike S wrote: Can you have a Cs under zero acceleration and at zero temperature, the only conditions for which the second is defined? Since most metric units are derived from the definition of the second, are any primary standards, in your opinion? Isn't it defined for zero sea-level, that is standard acceleration? At its 1997 meeting the CIPM affirmed that: This definition refers to a caesium atom at rest at a temperature of 0 K. - http://www.bipm.org/en/si/si_brochure/chapter2/2-1/second.html Sea-level would be 1 g of acceleration, would it not? ___ 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] One Kg Quartz Resonator
On 1/24/2013 10:38 AM, Jim Lux wrote: On 1/24/13 7:24 AM, Mike S wrote: On 1/23/2013 3:34 AM, Magnus Danielson wrote: On 01/23/2013 02:32 AM, Mike S wrote: Can you have a Cs under zero acceleration and at zero temperature, the only conditions for which the second is defined? Since most metric units are derived from the definition of the second, are any primary standards, in your opinion? Isn't it defined for zero sea-level, that is standard acceleration? At its 1997 meeting the CIPM affirmed that: This definition refers to a caesium atom at rest at a temperature of 0 K. - http://www.bipm.org/en/si/si_brochure/chapter2/2-1/second.html Sea-level would be 1 g of acceleration, would it not? which sea? OK, roughly 1 g, but that's missing the point. Which is, a real-world device that realizes the definition of the second is (currently?) impossible. That TAI is a weighted average of many standards I think supports that - real world devices must be compensated to be close, but still imperfect. My question was in response to a claim that if the number and type of atoms in such a standard (proposed 1 kg silicon sphere) couldn't be counted, its not a primary standard. The same logic could be applied to the second, and all derived units. ___ 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] One Kg Quartz Resonator
On 1/22/2013 3:30 PM, Bruce Griffiths wrote: But can the number and type of atoms in such a standard be counted? Otherwise its not a primary standard. Can you have a Cs under zero acceleration and at zero temperature, the only conditions for which the second is defined? Since most metric units are derived from the definition of the second, are any primary standards, in your opinion? ___ 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] Open source
On 12/7/2012 4:08 PM, Scott McGrath wrote: that was my point code is open source means open for inspection by end-user. The tool chain is irrelevant unless it comes from GPL or similar licenses. Back in the mainframe days most code was proprietary but distributed to customer in the form of source code to be compiled by the end user. That code was 'Open Source' e Not by the most commonly accepted definition: http://opensource.org/docs/osd ___ 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] Open source
On 12/7/2012 5:26 PM, Scott McGrath wrote: Well the GPL crowd has kind of conflated open source with code licensed under the GPL. And yes I have met Richard Stallman on many occasions. And I'm sure he would also disagree on my definition of open source You're confusing the two. Stallman promotes Free Software (simply put, libre, not like beer). GPL code is open source code. Open source doesn't have to be GPL. You're certainly free to have your own, unique, definition of open source, but don't expect it to be understood by others. 'There's glory for you!' 'I don't know what you mean by glory,' Alice said. Humpty Dumpty smiled contemptuously. 'Of course you don't — till I tell you. I meant there's a nice knock-down argument for you!' Heck under those terms code released under the BSD license does not qualify as 'open source'. Yes, it does. http://opensource.org/licenses/BSD-3-Clause Note that the definition of open source doesn't prohibit the code from being re-distributed under a non-open license, as the BSD allows, and the GPL prohibits. BSD is open source, but the BSD license allows one to modify the code, then sell it commercially and/or keep the code proprietary (i.e. distribute additional terms) - it's that modified code would no longer be considered open source. ___ 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] GPS antenna in attic?
On 11/26/2012 8:51 PM, Peter Gottlieb wrote: The antenna I got fron Nichegeek on ebay uses British Pipe Threads! Just can't get anything here that matches it. Perhaps I should just get a unit with regular NPT size threads? Why not just get a pipe nipple of close size, and grind off enough of the threads (if necessary) so you can JB Weld it in place, then go from there? ___ 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] Z3801A Problem
On 11/6/2012 2:59 PM, Ed Palmer wrote: But if this is a firmware issue, shouldn't there be lots of Z3801As with this problem? I suspect that there's a fault with my unit, but I can't imagine what. Does your unit by chance have an 8 channel Oncore VP instead of the stock 6 channel one? Also, have you tried a full reset (:system:preset)? ___ 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] Followup (still want a GPS-type NTP refclock)
On 10/18/2012 6:17 AM, Azelio Boriani wrote: Take care that the 1 satellite timing mode comes after having seens more than 4 satellites for at least 1 seconds (usually, or greater). You can't start a timing mode receiver with 1 satellite. Yes, you can. You only need to tell it its own coordinates, or have them previously stored in the unit. ___ 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] Z3801 Replacement GPS Receiver Card
On 9/15/2012 2:11 PM, paul swed wrote: Then respond back with whatever the response might be and then simply pass through in both direction whatever comes next. Could an updated rcvr be used. Is this init command really the only gotcha? It's more than just the init command. The z3801a also sends @@Ca, @@Cg, @@Ab, @@Ah, @@Aj, @@Ak, @@Al, @@An, @@Ar, @@Av, @@Ax, @@Ay, @@AB, @@AC, @@AD, @@Ba, @@Bc, @@Bk, @@Cg, @@At, and @@Bn, none of which are available on an M12 (which would be the logical target if you're going to the trouble of an adapter), so would need to be converted to other commands, and the correct response returned. In addition, the response to the @@Bb command (Visible sat status) would need modification. ___ 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] Reducing lab noise with LED lighting.
On 9/16/2012 8:09 PM, Tom Knox wrote: In this green era here in the USA there is a big push toward CFL lighting. Problem is I can see my CFL lighting on my PN measurements and other equipment. I am finding it is very noisy Run 12 VDC lighting, or hydrocarbon (NG/propane/naptha, which is noisy in a different way. ___ 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] Z3801 Replacement GPS Receiver Card
On 9/13/2012 1:39 PM, Chris Albertson wrote: On Thu, Sep 13, 2012 at 10:22 AM, gandal...@aol.com wrote: The GPS receiver in my Z3801 has died and I need to replace it. Go to ebay and type oncore in the search box. There are MANY available starting at just about $20. Search for oncore vp (which is what a z3801a needs), and you won't find ANY, at any price. ___ 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] Z3801 Replacement GPS Receiver Card
On 9/13/2012 2:00 PM, Chris Albertson wrote: On Thu, Sep 13, 2012 at 10:53 AM, Mike S mi...@flatsurface.com wrote: Search for oncore vp (which is what a z3801a needs), and you won't find ANY, at any price. Really? It can't use the newer UT? I thought the UT is identical except for better performance. Yes, really. The z3801a starts by sending a @@Ca (self test) command. None of the later models have that, so it fails. When they brought the self test back with the M12s, it was changed to @@Ia. Then it sends @@Cg (go to Position fix mode). They don't have that, either, it was changed to @@At on the UT/GT/SL, @@Gd on M12s. There are probably others, but that's more than enough to make anything later than a VP fail. ___ 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] RE; New Wrist watch
On 9/13/2012 4:45 PM, Azelio Boriani wrote: OK, listening to the 32KHz EM field, not to the acoustic 32KHz. I'm impressed by your special powers. ___ 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] Re; New Wrist watch
On 9/11/2012 11:58 AM, David McGaw wrote: Curious. Civil time is based on UTC, not GPS. Shouldn't the smart phones account for the difference from GPS time? We have the technology. The problem is, Google doesn't have a clue. The issue was first reported to them almost 3 years ago - http://code.google.com/p/android/issues/detail?id=5485 BTW, my Verizon CDMA dumb phone is currently only 1 second ahead, NOT 16 secs. It likely has a fixed correction built into firmware, and was in sync with UTC prior to the recent leap second. ___ 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] Re; New Wrist watch
On 9/10/2012 6:36 PM, Bob Smither wrote: May not be redundant for time nuts! I have an NTP client on my Android and it shows the network time (Sprint in my case) is often as much as 2 seconds behind UTC. So that makes it, what, 21 seconds off? It should be 19 seconds ahead of UTC, since Sprint has a CDMA network, which works on GPS time. It's likely you have multiple processes trying to pull the clock in different directions. Left alone, Android devices sync to network time, which is GPS, not UTC, in many cases. It's a bug, IMHO, but that's the way it is. ___ 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] What size graphs do people like? (How big is yourscreen?)
On 8/8/2012 1:41 PM, Chris Albertson wrote: On Tue, Aug 7, 2012 at 11:57 PM, Hal Murray hmur...@megapathdsl.net wrote: ps and pdf, at least the way I see them, are not in the same boat as SVG. SVG is an image format that can easily be included in a html page. ps and pdf are stand alone. They assume they control the whole setup and are targeted at paper. Think 8.5x11 or A4. Here is a random counterexample to the above. http://www.acousticscale.org/wiki/index.php/File:SHAR_PGW_2009_Staves.eps ?? That's a page, which despite its title, contains a .png image, so the image is viewable in a browser. The eps is here: http://www.acousticscale.org/wiki/images/a/a0/SHAR_PGW_2009_Staves.eps Try opening the real eps in your browser. ___ 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] web presentation of data
On 8/6/2012 12:57 PM, John Ackermann N8UR wrote: IMG SRC=image.big WIDTH=50% HEIGHT=50% The viewer can then right-click on the image and via the view image or similar menu open up the full-sized version for the fine detail. That worked on my browser and monitor, but apparently not on some other combinations. So, it's back to the drawing board. Try IMG SRC=image.big WIDTH=675 HEIGHT=506 (assuming a 1350x1012 original). Specifying an exact size is preferred, since it makes page rendering faster - the browser can do the layout before having to download the image to determine the size. ___ 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] Tag Heuer Mikrogirder
On 8/1/2012 12:19 PM, Brooke Clarke wrote: What's the claim for the Tag Heuer Mikrogirder? Their timekeeping can't be very good, as their alarms obviously don't work - their SSL certificate (*.tagheuer.com) expired 1/4/2012 11:59:00 PM GMT. ___ 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] Thunderbolt mounting
On 7/11/2012 8:15 PM, Chris Wilson wrote: Does anyone know if there's a means to log max and min temps for these things? I was going to make a crude box for mine out of 2 inch cavity wall insulation hard foam, The TB reports it's own temperature. Lady Heather will track it. I'm surprised no one has mounted one to a Peltier cooler, and stabilized the temp with PID control, based on the self-reported temp. Why not run it cooler than ambient? I'd assume a simple microcontroller could handle the task, but don't have any deep PID control knowledge myself. ___ 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] Leap second? Yay or nay?
On 7/2/2012 9:41 AM, Chuck Harris wrote: I know this is hard for you Mike, try and pay attention. Are insults really a necessary part of your argument? ___ 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] Leap second? Yay or nay?
On 7/2/2012 9:28 AM, Jim Lux wrote: but if we ARE going to establish artificial connections between wall clock time (work hours, store opening times, bar closing times, etc.) and the sun, why not do it gradually. Time and the sun are certainly a _natural_ connection, not an artificial one. Units of time start with the day. Subdivided, we get HMS, measured from the maximum height of the sun. Greater, years, which were measured in days. It's the artificial definition of the SI second which has caused all the problems. ___ 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] Leap second? Yay or nay?
On 7/2/2012 1:04 PM, Chuck Harris wrote: Clearly when you called me a Luddite you were passing me a complement? I called you no such thing. I asked if you were arguing from that point of view, since you were arguing against using technology because of the risk. That seems to be characterized fairly as a luddite view. There are groups of people who hold luddite views against technology, I don't agree with them, but wouldn't disrespect them by implying that a comparison to them was an insult. The question I posed has gone unanswered. All software has bugs, and that creates risk. Do you have some formula to determine a universally acceptable risk/benefit cutoff? For whatever reason, you have taken it upon yourself to behave like an ass towards me whenever I post on this group. Again, your arguments rely on insults, which only shows their value. If you feel threatened by arguments against positions you hold, it might be better to not mention them in the first place. The only group that really needs to have time match the Earth's rotation is astronomers. They can take care of their own needs by simply feeding a TAI like timescale to a library function that will apply the correction. As if TAI were the One True God, from which all else must flow. And that it's you who gets to decide what all others should need or want. there is no need for the time to perfectly match the earth's revolution for 99.99% of the population. OK, then there is no need for atomic clock precision wall/civil time for 100% of the population. Where such precision is needed, properly designed devices already use TAI or a variant (e.g. GPS, cellular systems). The artificial definition of the SI second is what created this mess. Better that they would have, like the meter before, simply created a new unit instead of usurping an existing one with a well understood meaning and a long historical record. Why not 1 chron = 10 Cs periods, instead of unlinking the second from astronomical time? Beyond that, as I've said, anyone who doesn't like leap seconds but uses UTC anyway has made their own bed. If they've been somehow forced into using it, live with it, or appeal to the authority which made that choice. Breaking what UTC was specifically meant to be (a close link to UTx) by eliminating leap seconds is simply the lazy man's kludge. It's very presumptuous to say we made a bad choice to use this thing with a messy characteristic we don't require, so let's change it and break things for those who made the choice precisely because they need/want that characteristic. ___ 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] Leap second? Yay or nay?
On 7/1/2012 8:24 PM, Jim Palfreyman wrote: Thoughts? UTC was specifically defined/specified to closely track the other UTx timescales. Breaking that link penalizes those who use it as it was intended. If being close to solar time isn't important for some applications, and they don't want to deal with leap seconds, they shouldn't be using UTC. There are multiple non-leap timescales already available for their use, or they can create a new one. If there are legal reasons they need to use UTC, work to change the laws. Returning to GMT (or a UTx scale not linked to the TAI rate) would be a logical choice. Eliminating leap seconds from UTC breaks it. ___ 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] Leap second coming...
On 6/29/2012 11:15 PM, Said Jackson wrote: This is one day not to be flying in a commercial airplane when it happens.. Who knows if the gps units crash, if their designers never checked mid-year leapseconds.. ? GPS uses GPS time, which doesn't have leap seconds. And, it's not like this is the first time there's been a mid-year leap second. The last one was 1997, so even mass market GPSs have been exposed to them. ___ 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] Leap second coming...
On 6/29/2012 2:46 AM, Hal Murray wrote: That's Friday, the 29th. The leap second doesn't happen until Sat, 30th. I think 23:59:59 UTC is 16:59:59 PST. UTC is 7 hours earlier than PST. For a time-nuts list, there sure seems to be a lot of confusion. He was off a day, you're off an hour. 23:59:59 UTC is 15:59:59 PST 23:59:59 UTC is 16:59:59 PDT (which I assume most wall clocks are set to) ___ 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.
[time-nuts] NTP leap second status...
OK, less than a day to go. At this point, properly configured NTP servers should show leap_add_sec, leap=01, and possibly leapsec=20120701. To check, do an ntpq -crv. ntpq -crv ipaddress to check a remote host (if it allows it). ___ 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] Spoofing GPS
On 6/26/2012 7:57 PM, li...@lazygranch.com wrote: If the GPS is jammed, the UAV goes into a failsafe mode. If the GPS _knows_ it has been jammed, the UAV goes into a failsafe mode. There, fixed that for you. ___ 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] Spoofing GPS
On 6/26/2012 9:53 PM, li...@lazygranch.com wrote: I have been around military jamming. The GPS goes to zilch. It isn't a soft degradation. Whoosh. The (off-topic) discussion is about civilian GPS, as used by civilian drones. I take it you didn't read the linked article from the OP, which described the successful operation of a $1000 spoofer. ___ 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] Thunderbolt GPS rollover
On 6/7/2012 9:45 PM, k4...@aol.com wrote: believe me, there is no fool proof solution to this. I don't believe you. One need only provide a command to allow manually setting the checkpoint date. ___ 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] Thunderbolt GPS rollover
On 6/7/2012 8:02 PM, Bob Camp wrote: One could put in a routine that looks at the date the software was written and fix any date that shows up as being in the past. After all the issues seen after the last rollover, I'd think receivers would have been made robust against this. One obvious method would be to keep a checkpoint date (or 1024 week cycle # + week offset) in EEPROM. To avoid issues with using up EEPROM r/w cycles, only update it anytime the currently received date is more than a year beyond the currently stored date. ___ 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] zero crossing of venus
On 6/6/2012 9:09 AM, Jim Lux wrote: does anyone have a reference to the math and process used to measure distance from earth to sun using transit of venus? http://transitofvenus.nl/wp/getting-involved/measure-the-suns-distance/ ___ 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] Serial port server .. any interest in a write up on using ?
On 5/22/2012 3:39 PM, Ed Palmer wrote: I've played with a Lantronix single port server and a Digi 16 port server with no problems for simple COM port emulation. But I wonder if they would work well with an NTP server. Has anyone tested that? Is the network delay a problem due to either amount of delay or variation in the delay? I use a Moxa NPort 5610 with a Thunderbolt for NTP. Only the serial goes through the Moxa, the PPS goes direct to DCD on a local serial port. I do that because the Moxa allows multiple access to the attached serial device, so I can run both NTP and Lady Heather against the Thunderbolt. Since NTP locks to the PPS, and only uses the serial for TOD, latency isn't an issue. The Linux drivers are, um, interesting, but they do work, once you get them configured and running. It appears as a serial device under /dev/. ___ 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] Why are 1PPS signals so skinny?
On 5/15/2012 2:45 PM, shali...@gmail.com wrote: The narrow pulses are easily filtered by the power supply because the frequency distribution of the power consumption has a much smaller component at 1Hz. But, since PPS is the leading edge, if the power draw for a longer pulse width causes timing problems, then a short pulse would too, unless the edge can somehow see into the future to know how long the pulse will last. ___ 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] Why are 1PPS signals so skinny?
On 5/15/2012 3:59 PM, Azelio Boriani wrote: seeing into the future for doing? Equalize the amplitude? Injecting/reducing the current to adjust the dV/dt? Can you explain? Once the leading edge has occurred, the only information of significance has been transmitted. What happens after doesn't matter. So what problem does a short pulse solve? ___ 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] Why are 1PPS signals so skinny?
On 5/15/2012 4:19 PM, Attila Kinali wrote: If the PPS pulse is short, it contains very little energy, which means the energy can be supplied by the small capacitors at the output driver. The longer the pulse gets, the more energy it needs. The pulse is meaningless. It's only the leading edge that matters. I understand how shorter pulses may make for marginally cheaper electronics. Which might have a negative effect on their performance. I might win the lotto. The question is exactly _how_ does it effect their performance, especially if they're synchronizing to the PPS signal. it's no use of having a fast rising edge, if the pulse colapses a couple ns later. Huh? If ns is too short, and ms is too long, what makes us just right? And why are there so many timing receivers that only output on the order of 20 us, when there are so many inputs which may require a few ms? PPS is edge triggered, not level triggered. Once the leading edge is transmitted (and it by necessity has a very fast rise time, so it looks to capacitors, transformers, etc. as a high frequency signal), the shape of the pulse really doesn't matter much. Some devices need more than a minimum above some threshold, but what ones need less than a maximum? If it doesn't look like a flat topped pulse, so what? As long as the decay is basically monotonic, and the receiver has some hysteresis (reasonable assumptions), it makes no difference. ___ 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] Why are 1PPS signals so skinny?
On 5/15/2012 5:14 PM, saidj...@aol.com wrote: it is the effect of what follows after that leading edge, and propagates down the power supplies to cause side effects that is being discussed here. I'm asking What side effects? I haven't seen any mentioned. And really, if an increase in power draw of 10 watts for an entire lab environment causes any problems, I'd question the quality of the power supplies, and ask what happens when you simply turn on the light? ___ 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] Why are 1PPS signals so skinny?
On 5/15/2012 8:58 PM, shali...@gmail.com wrote: Mike, here is the effect of the A/C cycling on and off during a warm spring day on the delay through a piece of RG-8 cable maybe 3 feet long: You're comparing the effect of voltage droop due to a 10W load on a 120V (or 240V, for Euros) AC feed with the temperature cycling plus voltage droop due to a 1000W+ HVAC unit? (Was your RG-8 in a separate climate enclosure? Or might you be including source/sink changes in your measurement?) Not only is 10W on a AC power feed pretty insignificant, but unless you're receiving a separate circuit from the substation, the building (or neighbor's) HVAC cycling will have more effect. All other comments have been unique to the performance of individual devices, not the propagation of PPS through a lab. ___ 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] Why are 1PPS signals so skinny?
On 5/14/2012 8:21 PM, Tom Van Baak wrote: one day during an experiment where I was comparing a large set of clocks I noticed my lab's digital AC power meter was jumping by tens of watts every second. The last thing you want in a precision timing lab is to load your AC line down exactly once a second. How does a short pulse help? It's still tens of watts every second, but instead of lasting 0.5 seconds, it lasts 0.5 seconds. Less power used overall, but still the same sudden change on the second. ___ 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] Faster than light of a different type
On 5/7/2012 7:22 PM, Cliff Sojourner wrote: one more thing, people need to learn to hit the delete key if they don't like a particular email. I prefer to simply subscribe to low noise sources, where I'm not required to get manually intervene. get over it. Don't tell me what to do. Get over yourself. ___ 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] NTGS50AA, better than Thunderbolt
On 5/3/2012 4:16 PM, Dan Rae wrote: Yes, he did. Unfortunately I didn't check since I still had the page open from earlier, and didn't find out till I went to Paypal... He certainly isn't getting positive feedback from me. You'd let your own oversight affect the feedback you leave? It's not his fault you didn't check the current listing. He has every right to change the price and/or shipping. ___ 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] Setting up PRS10 with M12+T GPS
On 5/2/2012 5:18 PM, Tom Knox wrote: I cannot believe my Guidetech GT4000 was left off your list. No worries. He didn't list the HP 5370A, either. ___ 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] NTP jitter with Linux
On 4/5/2012 2:51 AM, David J Taylor wrote: Mike, have you tried FreeBSD instead? Does it show the same problems? I have a couple of Soekris Net 4501s running FreeBSD and NTP. They don't have much jitter, but they're a very different architecture. The machine with the jitter is my home do all machine - router, firewall, file/email/print/web/ntp server, etc. It's certainly not critical to get rid of the jitter, it's a time-nuts thing. It bothers me. I noticed that when my backup process ran, NTP jitter dropped very significantly. I'm sure it's related in some way to interrupt latency - the first thing the PPS driver does when a PPS interrupt comes in is to save a nanotimestamp. Dennis Ferguson mentioned the OS idle loop. So, I added no-hlt to the kernel boot line. This did improve things quite a bit. All else the same, it reduces jitter to the 3-4 us range - better than the 20 us without, but not as good as the 1-2 when I simply load up the processor. ___ 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.
[time-nuts] NTP jitter with Linux
I asked this on an NTP list, got some guesses, but no knowledgeable responses. I've got a Trimble Thunderbolt PPS source for NTP, Linux 2.6.35, on a quad core CPU. PPS source is coming into a multiport serial card, which /proc/interrupts shows is sharing IRQ with some inactive USB ports (IRQ 17). It's a PCI-E card, so it would be using MSI interrupts. My understanding is that those aren't really shared, in the traditional sense, but IDK. The kernel clocksource is TSC, which is claimed to be core invariant on my processor (AMD Athlon II 610e). Changing to HPET doesn't help. Running normally, I'll get about +- 20 us ptp of jitter (as reported by ntpq -p, and in loopstats). If I load up the CPU (load average 4 is swell), jitter will shrink to +- 1-2 us. I've played around with different cpufreq setting, thinking it might be related to the processor speed during an IRQ varying, but that seems to have minimal impact (performance vs. conservative vs. ondemand). I've also tried irqbalance, with no change in performance. So, running a process(es) which keep the CPU completely busy reduces the jitter. The busier, the better. Why? I'm guessing it has something to do with interrupt latency, but why does a busy CPU make it more consistent - I'd expect the opposite? The difference is very obvious. Is there something else I can do to keep the jitter low? Aside: Something which I believe was discussed here a few weeks ago - clocksource speeds changing between reboots. I patched the kernel to allow statically setting the TSC frequency ( http://old.nabble.com/-PATCH--tsc_khz%3D-boot-option-to-avoid-TSC-calibration-variance-td23494975.html ). This eliminates the semi-random, often 30-40 ppm change in frequency reported by NTP between reboots. After tweaking, it's now consistently 1 us, reboots be damned. This should be in the mainline kernel! This made no difference to the jitter mentioned above, although non was expected. ___ 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] NTP jitter with Linux
On 4/4/2012 6:51 PM, Eric Williams wrote: Could the CPU be reducing its clock rate when it's not being loaded? Just a guess, most multi-core processors these days have power saving features like that. On Wed, Apr 4, 2012 at 3:22 PM, Mike Smi...@flatsurface.com wrote: I've played around with different cpufreq setting, thinking it might be related to the processor speed during an IRQ varying, but that seems to have minimal impact (performance vs. conservative vs. ondemand). Setting /sys/devices/system/cpu/cpuX/cpufreq/scaling_governor to performance should lock that core to the max clock rate. In looking that up, I found that the script I made to set this was just doing cpu0 (i.e. one of four cores). Doh! I've changed it to do all 4 cores, and am trying that again to see if that's it. ___ 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] NTP jitter with Linux
On 4/4/2012 10:41 PM, Steve . wrote: breaking the 1pps down as far as 10micro seconds,The most obviously problem is that you are trying to use an inaccurate clock source(the pc) Your reply ignores the simple fact that it _does_ track within a couple of microseconds, as long as the processor is busy. The PC is _not_ the clock source, a PPS signal derived from GPS is. A PC is perfectly capable of 10 us accuracy. Even slower processors are capable of significantly better accuracy - http://www.febo.com/pages/soekris/ . Trying to tweak a PC to get 10microseconds (nyquist, 5microseconds max) ??? Maybe your PC runs in MHz, but mine runs in GHz. Are you confusing us with ns? ___ 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] Antenna for t-bolt
On 4/2/2012 5:39 PM, Bill Riches wrote: Question is that I am looking for suggestions for GPS antenna for t-bolt. I use an Andrew GPS-QBW-26N (quadrifilar). 26 db amp + 4 db antenna gain, through an HP 58516 distribution amp. Works well for me. ___ 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] Yahoo group not receiving emal
On 3/29/2012 3:16 PM, Attila Kinali wrote: If you are using yahoo as your webmail, change! quickly! They're not called yahoos for nothing. But, Microsoft and Google aren't far behind in Internet cluelessness. http://www.merriam-webster.com/dictionary/yahoo ___ 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] Best reason
On 3/28/2012 1:42 PM, David McGaw wrote: I never have considered quartz watches to be better unless they can be adjusted, which most cannot. Most decent ones can be. I've got some Citizens and Seikos, which have a small trimmer cap you can adjust. There's usually a test point nearby with a easy to figure out frequency output you can look at with a good counter (I think I've seen both 100 Hz and 32768 Hz outputs). ___ 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] Distribution amp - Use a video amp unit ?
On 3/25/2012 9:54 PM, gary wrote: MMBD914 !=1n914. 1n914BWTm i.e. using a suffix, is something I haven't seen before, but technically 1N914BWT != 1n914. That is, in the strict sense, the 1n914 has to be a diode in that glass package. As long as we're being pedantic, you're wrong. What you say is only true if it is a JEDEC 1n914 that you're talking about. 1n914 cannot be trademarked or copyrighted. A manufacturer is perfectly free to make a device in a non-glass package and call it a 1n914, which means it _is_ a 1n914, as long as they stay away from JEDEC. Then again, following your lead in being impractically, completely, worthlessly pedantic, it's a JEDEC 1N914, not a 1n914. In the strict sense, the latter cannot exist under JEDEC. No one cares is probably an understatement. ___ 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] Distribution amp - Use a video amp unit ?
On 3/26/2012 10:10 AM, Chuck Harris wrote: The glass used to make the body of the diode melts at something like 1500C! I think they're sintered, not melted, and it's more like 700 C - http://www.us.schott.com/epackaging/english/glass/technical_powder/passivation.html# ___ 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] FCC Chair Talks Spectrum, Gets GPS Letter
On 3/6/2012 10:37 PM, saidj...@aol.com wrote: I'm sorry, but Mr. Javad is on crack. Yeah right. In what world does he live in? The one in which he's head of the only company who offers GNSS receivers with ... LightSquared Inside. http://javad.com/jgnss/javad/news/pr20110921.html ___ 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] Low-Cost Rubidium Performance
On 2/9/12 4:51 AM, WarrenS wrote: Indeed, ADEV is for random freq variation not easily measured by other means. Temperature fluctuations do not cause random freq changes and the temperature's effect should be removed if one wants accurate long term ADEV numbers. Why? Unless the unit is spec'd for use only at a constant temperature, temperature variations are something it needs to deal with, and should be included in any measurement of how good it is. In what way is temperature variability special, that it shouldn't be included in ADEV measurements, but all other contributors to variability should be? Certainly, there may be a large non-random component to temperature (diurnal, annual, in many environments), but there's also a significant part which is random - should you somehow correct for one, but not the other? Shouldn't one expect the ADEV be better for a double oven OCXO than for a bare crystal? The only issue I see is it may make fair comparison difficult, unless units are compared under identical conditions. ___ 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] Low-Cost Rubidium Performance
On 2/9/2012 11:34 PM, ws at Yahoo wrote: You can of course use the ADEV math function for anything, but MY definition of true and accurate ADEV numbers must include a set up that gives repeatable results. If you test is done over different or unknown temperature changes that have major effects, then I'm calling that poor ADEV data (taking). Then you had better control acceleration (gravity/shock/vibration), voltages, humidity, pressure, electromagnetic fields, et al, if you want validity. Again, what makes temperature a unique case? ___ 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] (OT) linkedin spam
On 2/3/2012 3:40 PM, J. Forster wrote: In theory only. I have been on both FaceBook and LinkedIn Do Not Contact lists, and I got another spam within the last two days. That may merely be phishing. I've seen quite a few lately, which are made to look like they originate from LinkedIn, but don't. Headers make it obvious, but URIs also don't match, and probably point to some website which tries to get personal info. ___ 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] Invitation to connect on LinkedIn
On 1/25/2012 5:02 PM, J. Forster wrote: This is intolerable data mining by LinkedIn. FaceBook does the same thing. It is spread either by malware or purposeful deception by those companies. I don't think so. AIR, when you sign up for LinkedIn, it offers to harvest your address book for potential links. It's up to the user to accept. Presumably, this is the case of a clueless newbie, who subscribes to this list, stripping naked before them. ___ 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] hijacking threads
On 1/23/2012 4:41 AM, Hal Murray wrote: You didn't cleanup the headers. Your message contained: References:cabbxvhtj3b3kbzshesqqzca_do8fak2fxnam4foekttokfw...@mail.gmail.co That's not really his fault. Thunderbird does it wrong. RFC 1036: 2.2.5. References - This field lists the Message-ID's of any messages prompting the submission of this message. It is required for all follow-up messages, and forbidden when a new subject is raised. Of course, threading has been messed up from day one. Not all MUAs support the desired headers, and many get it wrong. Instead of complaining when threading breaks, people should be thankful when it works. That's just the nature of the beast. ___ 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] hijacking threads
On 1/23/2012 9:58 AM, Chuck Harris wrote: I don't think it is clear that editing the Subject line is the same as raising a new subject. In the context of the References header, as was being discussed in the RFC, that's all it _can_ be (editing the subject line). When creating a message from scratch, there's no References header to deal with, and no Message-ID being replied to, so the comment simply doesn't apply. ___ 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] finding time astronomically.
On 1/23/2012 3:02 PM, Jim Lux wrote: How well could you do with something like the camera in the iPhone4 facing up. The front camera is VGA resolution A lower bound can be estimated. A cell phone (iPhone 4 rear camera) camera sensor has a resolution of what? ~2600 pixels wide with a 45 degree field of view - that's ~ 60 arc seconds per pixel, which is about 4 seconds of time. The Dawes limit is about 1 second (17 arc-seconds) for a perfect .25 lens. Obviously worse with a VGA resolution camera. Can such a camera even see stars? ___ 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] 15 Seconds error...??
On 1/18/2012 4:36 PM, Magnus Danielson wrote: Use of TAI is fine, as long as you won't tell anyone near the timelords, as obvious TAI is supposed to be hands off. You said something similar a couple of times. Where does that come from? Who says you're not supposed to use TAI, and why not? Why would there be a well defined time scale which isn't meant to be used? ___ 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.
