Re: [time-nuts] Open source
In message cabbxvhujtsd4btdq7dbm88-gfuv9kbesr5_jovaeubvrjnc...@mail.gmail.com, Chris Albertson writes: Many authors ike GPL because they figure I wrote this and I'm giving this away for free, I don't want some other guy to take it, change the title and claim it as his own work and charge money for it. BSD on the other hand allows it The University of Califoornia used BSD because their goal was to get the technology out into the world and allowing someone to make money is a good way to do that. The BSD license does not allow you to claim it is yours, in fact, no license is needed to preserve that right, as the Berne Convention and all copyright laws I know about, protects the creators ideal rights (= the right to be known as the creator) by default. In practice there are a few other wrinkles between GPL and BSD. In particular the GPL code can taint your own code if you get them too close together, so that you can be forced to release your own code as GPL, simply by using a GPL submodule. (This is why some license-fanatics call the GPL a viral license) And one other detail most people overlook, is that the default GPL text gives any users the right to use any later version of the GPL license instead of the one you copypasted. This has only happened once but it had ground-shaking repercussions through out the industry. As for the economy, as an open source author, my experience is that there is more money to be made with the BSD license than with the GPL license, simply because the companies which might be willing to pay, also like the extra freedom of the BSD license. And as was said, there is a ton of other OSS-licenses out there, you can see a sort of a list here: http://opensource.org/licenses/index.html my own contribution to the area, was used on a piece of code I wrote, which during its most popular use-period, protected upwards of 50% of all passwords on the internet: http://en.wikipedia.org/wiki/Beerware -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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 8 December 2012 01:09, Chris Albertson albertson.ch...@gmail.com wrote: BTW you CAN make as much money as you like with GPL'd software. Just look at all Android phones. They contain Linux and a pile of other GPL'd software. Apple is using BSD Unix in there products. That's an important point, and something the person that wrote the GPSDO software might like to consider. You don't need to be the size of Apple to make money from GPL. Plenty of people earn money from providing support for GPL software. There are numerous consultants for R (statistics package), Apache (web server), Wireshark (network analysis) etc. I've made money by selling support for a GPL program I wrote. http://atlc.sourceforge.net/ with hindsight, I could have probably made more, as a commerical company contacted me, asking if I could license it under the LGPL so they could use it in their closed-source commerical software. I refused. But with hindsight, I could have sold them a license to use it in their closed source application. As a company, if you use GPL software, you are not tied to one vendor. If there is a feature you want, you can eitiher add it yourself, ask the original author to add it, or if need be pay someone else to add it. Dave ___ 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] Termination talk
On Fri, 07 Dec 2012 23:42:44 +0100 Magnus Danielson mag...@rubidium.dyndns.org wrote: Only then he made the comment that there might be something in that Black Magic book that I had bought and distributed. Which book would that be? Attila Kinali -- There is no secret ingredient -- Po, Kung Fu Panda ___ 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 8 December 2012 08:36, Poul-Henning Kamp p...@phk.freebsd.dk wrote: And one other detail most people overlook, is that the default GPL text gives any users the right to use any later version of the GPL license instead of the one you copypasted. This has only happened once but it had ground-shaking repercussions through out the industry. I don't agree with that statement. Look at GPL 2 (not the latest version). http://www.gnu.org/licenses/gpl-2.0.html Section 9 states: Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and any later version, you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation. Note the term: *IF* the Program specifies ... My interpretation of the GPL if you specify version 2, and do not specify or any later version, then the code is released under version 2, and can't be used under any later version. This compatibility matrix http://www.gnu.org/licenses/gpl-faq.html#AllCompatibility makes it clear if the code is released under GPL 2, without the or any later version clause, it is incompatible with version 3. And as was said, there is a ton of other OSS-licenses out there, you can see a sort of a list here: http://opensource.org/licenses/index.html Unfortunately, the large number of licenses is a real pain. The Sage mathematics project http://www.sagemath.org/ which aims to create a viable free open source alternative to Magma, Maple, Mathematica and Matlab, is plagued by the problem of incompatible licenses, Sage contains the source code from around 100 different bits of software and needless to say some are incompatible. In some cases, when consideration was given to including the source of some program X released under the GPL 2, the projects lead (William Stein) or someone else has contacted the original author of X, and asked them if they will re license it under Version 2 or any later version. In other instances, packages were made optional, so people could install them if they wanted, but it would be under a different license. Personally I'm not convined that Sage fully complies with the licenses and I'm not the only Sage developer to think that. But the projects lead is happy. The amount of time spent on the Sage developers mailing list discussing license issues is not insignificant. This is a direct result of various components having different licenses. Dave ___ 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] Termination talk
att...@kinali.ch said: Only then he made the comment that there might be something in that Black Magic book that I had bought and distributed. Which book would that be? High Speed Digital Design: A Handbook of Black Magic Howard Johnson (Author), Martin Graham Amazon charges $81.64 (down to $63 through their affiliates ???) I really like it. Mostly, it's covering PCB design for 1993 technology. If you are interested in things like the recent reflection discussion this is what you want. It's probably not good enough for modern superfast logic. -- These are my opinions. I hate spam. ___ 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
In message canx10haonf8mauotcr9w8k9wm-ckbgkqqujm6epq5wzrqp5...@mail.gmail.com, David Kirkby writes: On 8 December 2012 08:36, Poul-Henning Kamp p...@phk.freebsd.dk wrote: And one other detail most people overlook, is that the default GPL text gives any users the right to use any later version of the GPL license instead of the one you copypasted. This has only happened once but it had ground-shaking repercussions through out the industry. I don't agree with that statement. You underestimate the power of blind copypaste here: The point is not that you _can_ modify the license on this detail, but that most people don't realize that they should, and the default has the ...or later language in it. Unfortunately, the large number of licenses is a real pain. [...] The amount of time spent on the Sage developers mailing list discussing license issues is not insignificant. Yes, license-triage is a major task in many Open Source projects, we have spent oodles of time on it in FreeBSD as well. Personally I'm not convined that Sage fully complies with the licenses and I'm not the only Sage developer to think that. And, short of a trip through a court, there is no way you can be sure. All part of life in FOSS... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] PTTI 2012, part 3/3
They did respond back and I am limited to 1. Wanted 2 but such is life. :-) Will order most likely Monday. Regards Paul WB8TSL You were lucky, Paul. I have so far received no response to my query. 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ 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] Frequency generator and counter on same external reference
Two rules to follow. 1 - use well shielded cables for the 10 MHz distribution if you wish to receive WWV 10 off the air. The skinny cables used for Ethernet generally don't cut it. 2. Most instruments have a high impedance 10 MHz input. Put them in the middle with T connectors left over from your 10 base T days. If you have an instrument that terminates the 10 MHz input, it goes last. Otherwise use a terminator at the end. I have an Advantest spectrum analyzer, HP selective level meter, Racal-Dana counter, Flexradio 1500, and Gigatronics generator daisy chained from a Thunderbolt. Plenty of signal, and the fat (well shielded) cables let me listen to WWV. 08/12/2012 11:30 Thanks for that Chuck, appreciated. -- Best Regards, Chris Wilson. ___ 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] PPS offset between GPS receivers
Date: Fri, 7 Dec 2012 22:28:20 -0500 From: Bob Camp lists at rtty.us Hi A lot depends on exactly what the interrupt structure is. It may also depend on the phase of the cpu clock relative to the pps signal. What's reasonably sure is that there is indeed some offset between the two where the answer is indeed ft's random. Another thing to check - how wide is the random region? Bob On Dec 7, 2012, at 9:19 PM, Chris Albertson albertson.chris at gmail.com wrote: One more test to try. Connect one PPS signal to both GPIO ports and see how close to zero offset you get. It would likely be random which gets read first. I'm using an Atheros ar71xx platform, the GPIO driver does not use interrupts so I'm using an experimental polling PPS driver: http://code.google.com/p/openwrt-stratum1/wiki/PpsGpioPollDriver The jitter is low, about 100 ns p-p (see graph on the main page). A TIC mode could be added to measure the difference between events on two GPIO ports. I had an NTP server which had PPS on the serial port DCD and the parallel port ACK, both derived from the same source. When both are connected, the serial port timestamps are 10 us late. When the parallel port is disconnected, the delay drops to 5 us. Probably the parallel port ISR is executed first and delays the serial port ISR. ___ 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] PPS offset between GPS receivers
Yes, this is a good test: to evaluate how your preferred uP can perform as a time interval counter, you can hook two GPDSOs' PPS to it and see the result. The best would be to have at hand also a real TIC (HP53132A, PM6681, SR620 or similar) and compare. On Sat, Dec 8, 2012 at 4:28 AM, Bob Camp li...@rtty.us wrote: Hi A lot depends on exactly what the interrupt structure is. It may also depend on the phase of the cpu clock relative to the pps signal. What's reasonably sure is that there is indeed some offset between the two where the answer is indeed ft's random. Another thing to check - how wide is the random region? Bob On Dec 7, 2012, at 9:19 PM, Chris Albertson albertson.ch...@gmail.com wrote: One more test to try. Connect one PPS signal to both GPIO ports and see how close to zero offset you get. It would likely be random which gets read first. On Wed, Dec 5, 2012 at 5:37 AM, Gabs Ricalde gsrica...@gmail.com wrote: Hi everyone, As Tom suggested, I redid the test with less than 1 ft. of wire from the PPS output to the GPIO without any logic gates or line receivers. Same result, the SKG25A1 was 2 microseconds ahead of the 58534A. Without any other way of testing, I would probably trust the output of the timing receiver more than the SkyNav module. Anyway the SkyNav board is an inexpensive unit and I wouldn't mind setting an offset in ntpd. I don't have a scope yet, and a low jitter PPS GPIO is the closest thing I have to a TIC. ___ 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. -- Chris Albertson Redondo Beach, California ___ 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 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 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] YIG oscillator drift question
Does anybody have direct experience on playing with YIG oscillators? I have read some specs on drift, but I know they are usually worst cases. I would like to get a raw idea about real measured drifts in reasonably stable temperature for a free running YIG with no tuning current. Yes, of course this depends on make, model etc, but any advise would be appreciated.Thanks in advance,Antonio I8IOV ___ 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] YIG oscillator drift question
I do not have any data on temperature drift, but I can say that most YIG oscillators I have used, with the exception of the Stellex-mini models, have required a tuning current to oscillate. The Stellex-mini models have a strong bias magnet which allows the tuning current to be zero at mid tuning range. John WA4WDL -- From: iov...@inwind.it Sent: Saturday, December 08, 2012 9:17 AM To: time-nuts@febo.com Subject: [time-nuts] YIG oscillator drift question Does anybody have direct experience on playing with YIG oscillators? I have read some specs on drift, but I know they are usually worst cases. I would like to get a raw idea about real measured drifts in reasonably stable temperature for a free running YIG with no tuning current. Yes, of course this depends on make, model etc, but any advise would be appreciated.Thanks in advance,Antonio I8IOV ___ 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 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] YIG oscillator drift question
Hi If you have a magnetic field, the net TC will depend on the core material in the magnet. That can be a that depends sort of thing. The high perm materials are often strange over temperature. I suspect the only real answer will be to measure the one you have in your environment. Bob On Dec 8, 2012, at 9:17 AM, iov...@inwind.it wrote: Does anybody have direct experience on playing with YIG oscillators? I have read some specs on drift, but I know they are usually worst cases. I would like to get a raw idea about real measured drifts in reasonably stable temperature for a free running YIG with no tuning current. Yes, of course this depends on make, model etc, but any advise would be appreciated.Thanks in advance,Antonio I8IOV ___ 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 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] YIG oscillator drift question
I do not have any data on temperature drift, but I can say that most YIG oscillators I have used, with the exception of the Stellex-mini models, have required a tuning current to oscillate. The Stellex-mini models have a strong bias magnet which allows the tuning current to be zero at mid tuning range. John WA4WDL Hi John, zero current is not a demand, but simply an illustrative situation in which current is ruled out as a reason of drift. By the way, I don't have any YIG oscillators on the bench yet, I should buy some. Antonio I8IOV ___ 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] Termination talk
On 12/08/2012 10:27 AM, Hal Murray wrote: att...@kinali.ch said: Only then he made the comment that there might be something in that Black Magic book that I had bought and distributed. Which book would that be? High Speed Digital Design: A Handbook of Black Magic Howard Johnson (Author), Martin Graham Amazon charges $81.64 (down to $63 through their affiliates ???) I really like it. Mostly, it's covering PCB design for 1993 technology. If you are interested in things like the recent reflection discussion this is what you want. It's probably not good enough for modern superfast logic. It is, but it does not cover modern PCB layout technologies, which is why there is a much thicker follow-up book. Cheers, Magnus ___ 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] Search Time-Nuts Archive?
Is there a way to search the Archive? I can find the archive, but there seems to be no way to search the content. Thanks, Mike Michael Garvey Swampscott, MA 01907-1907 USA ___ 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] Search Time-Nuts Archive?
I don't have an internal search engine on the server, but most folks just do a google search using the site:febo.com option and that seems to work well. John On Dec 8, 2012, at 11:24 AM, Mike Garvey r3m...@verizon.net wrote: Is there a way to search the Archive? I can find the archive, but there seems to be no way to search the content. Thanks, Mike Michael Garvey Swampscott, MA 01907-1907 USA ___ 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 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] Search Time-Nuts Archive?
Easiest way is to use google with site:febo.com as one of the search words. For example, if one were interested in an old FTS 4050 cesium clock google for: site:febo.com fts 4050 /tvb (iPhone4) On Dec 8, 2012, at 8:24 AM, Mike Garvey r3m...@verizon.net wrote: Is there a way to search the Archive? I can find the archive, but there seems to be no way to search the content. Thanks, Mike Michael Garvey Swampscott, MA 01907-1907 USA ___ 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 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 DO Alternatives
Hello all - People talk about good deals on Thunderbolts but I have yet to see one. It seems peak Thunderbolt passed before I was seriously looking. I would suggest some more serious looking. This guy TRIMBLE GPS RECEIVER 10MHZ CLOCK THUNDERBOLT currently has more than 10 T-bolts for sale on eBay as of this morning for $ 175. Last summer I bought 3 of his units and all were in great condition and worked just fine. the one pictured and all of the ones I obtained had a nice MiniCircuits 2 way splitter that came with it. The splitter is about $ 50 new and usable at 10 MHz and over a wide bandwidth. In fact during the several days of lamenting the lack of T bolts there were several vendors offering them for various prices from good to not so good. As to building a GPS DO some of the recent comments from persons dedicated to precision time and frequency - apparently willing to go to extreme measure to achieve it seem curious to say the least. Here performance seemed to be unspecified and of less importance than what uP to use. As usual there was the temptation to jump to implementations without the steps essential to any good design to wit: 1. A agreed to requirements document 2. A peer reviewed specification 3. A conceptual design and conceptual packaging concepts (What should the box cost?) 4. A conceptual design review 5. A preliminary circuit design, SW design, and final package concept. 6. Implementation and test of the preliminary circuit and SW design. 7. Incorporation of the test results and final design release. Instead the discussion has centered on what microprocessor (of a hundred that would work) and how to eliminate glue logic and and a few analog parts to save money. This is silly - silicon is CHEAP. Major cost items not considered include - somewhat in order of decreasing cost : *The box you put it in - suspending it above the bench on inspirational thought probably will not work. A nice box is easily $ 50.00 so who cares about adding another flip flop or counter at 25 cents each. *The printed wiring board. Most costly per unit up to about 4 pieces * A power supply - you will need a good low noise one. * OCXO So when you look at the total system - any GPS DO when fully developed and packaged into a unit with long term reliability and performance acceptable to this group is a non-trivial project. It is, however a challenging and rewarding project - particularly if well done. -73 john k6iql -Original Message- From: time-nuts-request time-nuts-requ...@febo.com To: time-nuts time-nuts@febo.com Sent: Sat, Dec 8, 2012 2:56 am Subject: time-nuts Digest, Vol 101, Issue 63 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: GPSDO Alternatives - Bert's boards (WB6BNQ) 2. Re: PPS offset between GPS receivers (Chris Albertson) 3. Re: GPSDO Alternatives (David) 4. Re: PPS offset between GPS receivers (Bob Camp) 5. Re: Open source (Poul-Henning Kamp) 6. Re: Open source (David Kirkby) 7. Re: Termination talk (Attila Kinali) -- Message: 1 Date: Fri, 07 Dec 2012 18:06:17 -0800 From: WB6BNQ wb6...@cox.net To: Discussion of precise time and frequency measurement time-nuts@febo.com, ewkeh...@aol.com Subject: Re: [time-nuts] GPSDO Alternatives - Bert's boards Message-ID: 50c2a099.cbfda...@cox.net Content-Type: text/plain; charset=us-ascii Hello Bert, The boards look nice but tell me nothing of the circuitry. How about sending the schematics ?? That way I can appreciate what it is that you have. BillWB6BNQ p.s. By the way, what ever happen with that DMTD you were going to produce about three years ago ? ewkeh...@aol.com wrote: Attached is my latest ExpresPCB layout of a GPSDO. A clear understanding of the GPS limitations, a goal as to what I want to control ,focus on attainability, reproducibility KISS, cost and tests of partials on development boards and what you see if you download the ExpessPCB software is on the right the saw tooth correction, in the middle the analog board with opto isolation to prevent ground loop and on the right the actual GPSDO. This particular unit also allows you to link a 20 Hz offset FRS-C (part of my dual mixer) to my house reference. Total material cost depending how many boards one buys is below $ 40. I will include this particular board along with other designs on my next order and subsequently cut with a sheer. The board on the right could be
Re: [time-nuts] PPS offset between GPS receivers
I use a tee connection and terminated 100 foot (33 m )piece of RG58 coax for a known delay to the stop pulse. Don L Azelio Boriani Yes, this is a good test: to evaluate how your preferred uP can perform as a time interval counter, you can hook two GPDSOs' PPS to it and see the result. The best would be to have at hand also a real TIC (HP53132A, PM6681, SR620 or similar) and compare. On Sat, Dec 8, 2012 at 4:28 AM, Bob Camp li...@rtty.us wrote: Hi A lot depends on exactly what the interrupt structure is. It may also depend on the phase of the cpu clock relative to the pps signal. What's reasonably sure is that there is indeed some offset between the two where the answer is indeed ft's random. Another thing to check - how wide is the random region? Bob On Dec 7, 2012, at 9:19 PM, Chris Albertson albertson.ch...@gmail.com wrote: One more test to try. Connect one PPS signal to both GPIO ports and see how close to zero offset you get. It would likely be random which gets read first. On Wed, Dec 5, 2012 at 5:37 AM, Gabs Ricalde gsrica...@gmail.com wrote: Hi everyone, As Tom suggested, I redid the test with less than 1 ft. of wire from the PPS output to the GPIO without any logic gates or line receivers. Same result, the SKG25A1 was 2 microseconds ahead of the 58534A. Without any other way of testing, I would probably trust the output of the timing receiver more than the SkyNav module. Anyway the SkyNav board is an inexpensive unit and I wouldn't mind setting an offset in ntpd. I don't have a scope yet, and a low jitter PPS GPIO is the closest thing I have to a TIC. ___ 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. -- Chris Albertson Redondo Beach, California ___ 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 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 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. De Erroribus Medicorum, R. Bacon, 13th century. If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ 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 DO Alternatives
On Sat, Dec 8, 2012 at 9:30 AM, johncr...@aol.com wrote: Hello all - People talk about good deals on Thunderbolts but I have yet to see one. It seems peak Thunderbolt passed before I was seriously looking. *The box you put it in - suspending it above the bench on inspirational thought probably will not work. A nice box is easily $ 50.00 so who cares about adding another flip flop or counter at 25 cents each. The goal, well my goal is to build a GPSDO to this set of requirements 1) well under 1/2 the cost of the t-bolt. 2) can be made with common parts and skills most people have 3) is completely modifiable (open source software) So #1 above means you use a low cost box, perhaps the case and old CDROM was once housed in or maybe you gut and old PC chassis #2 pretty much means you have to keep theparts cound way down. Yes a chip might cost only $1 but as soon as you get more then about three of those 25 cent cips you need a PCB. PCB making is not a common everyday skill so #2 means a way-low parts count #3 means the uP is gong to have to come with a very easy to use and free open source toolchain. Adruino is like that, there are others, but a bare uP chip is not going to work You are right that one way to engineer a product is to first set performance numbers. But another more common way is to first identify a target customer and then set a target price. In this case the target customer is a hobbyist with only basic skills who wants a low cost easy to build GPSDO that has can understand and modify himself. Next with those very hard to meet requirements (low cost, low parts count, simple to build) we can ask if the exected perfomance is good enough What is good enough. I'd say if you could use the GPSDO a a local frequency standard for a counter that has 8 digits you are doing well enough. If you can get to 10 digital it is pretty good -- Chris Albertson Redondo Beach, California ___ 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 DO Alternatives
Chris wrote: The goal, well my goal is to build a GPSDO to this set of requirements 1) well under 1/2 the cost of the t-bolt. 2) can be made with common parts and skills most people have 3) is completely modifiable (open source software) * * * if you could use the GPSDO a a local frequency standard for a counter that has 8 digits you are doing well enough. If you can get to 10 digital it is pretty good OK, if we assume that a Thunderbolt is $200 these days, the GPSDO module (no PS, no antenna) needs to be well under $100. So, $75-80? And to be clearly good enough for an 8-digit counter with one-digit overrange using gate times of 1 and 10 seconds, it should have an ADEV ~ 1e-10 at tau = 1 and 10 seconds. Go down one power of ten for each digit over 8, and up one if the counter does not have overrange. The performance at tau = 1 and 10 seconds will be largely dependent on the quartz oscillator used, assuming that its performance over the next two or three decades allows one to set the time constant of the discipline loop out in the 500 second range. 1e-10 is a bit more than one order of magnitude worse than an average Thunderbolt. [1e-12 (what you would need for a 10-digit counter with one digit overrange) is somewhat better than you can expect from an average Thunderbolt. 1e-11 (what you would need for a 10-digit counter with no overrange, or a 9-digit counter with one digit overrange) is just about what an average Thunderbolt delivers.] The holdover performance of the DIY box would likely not be as good as the Thunderbolt, because any sub-$100 implementation that can be made with common parts and the skills most people have is unlikely to include Kalman filtering or other predictive steering during holdover (but as I said in a previous message, holdover performance may not be required by many amateur time nuts, who can simply restrict their use of the standard to periods when it is performing nominally). As we have discussed many times here, the control loop is much easier to design if it is comparing the 10 MHz output to a frequency much higher than 1 Hz. This is why the original Miller DIY GPSDO (http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm) (http://www.jrmiller.demon.co.uk/projects/ministd/manual.pdf) is able to achieve such good results (comparable to an average Thunderbolt) with a very simple design -- it uses Jupiter GPS engines with a disciplined 10 kHz output. I believe the PC card may still be available, for those who can find a Jupiter to use it with. (Note that Mr. Miller also supplies a ready-made version of the GPSDO with Axtal OXCO, but that one costs well more than a Thunderbolt.) The design goals stated above are ambitious, and I suspect it will be a challenge to come in on budget even with the relaxed stability requirement compared to a Thunderbolt. But I do hope you give it a go, and will be most interested to see what you come up with. Best regards, Charles ___ 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] YIG oscillator drift question
Yes, something must supply the minimum magnetic field to activate the oscillator - but the current determines the field, so it's necessarily part of the drift characteristic. It also depends on whether the YIG sphere is heated - usually to 80 deg C or so, to help stabilize it. Without any other frequency control, you can expect it to stay within about +/- 10 MHz of the frequency predicted by its tuning curve. It is very linear with magnetic field, hence tuning current, until the core material begins to saturate at high flux levels, so the tuning current needs to be increased to compensate. The most common type is one-octave 2-4 GHz, used in spectrum analyzers from the 1970s on, and also the first microwave band of many generators. Another common one is the 2-6.X GHz also used for the same purposes, but covering a wider direct range. The next bands up are typically 4-8, 6-12, 8-12, and 12-18 GHz, used in generators, at least in older gear. You can expect to find about +10 to +18 dBm output power range, and fairly flat with frequency. The minimum setup is one or two power supplies, plus a variable coil current driver up to one amp or so. You don't need the heater to run it. Don't bother with the FM coil - it's not needed for basic experimenting, and it's easy to burn out if you screw up. The main coil is more robust, but it can be burned out with too much current, so don't go too far beyond the maximum tuning current spec. It can also shock you from inductive kickback, so the coil needs clamping too. It's best study the circuits of existing sweepers and such to get ideas on how it's all done. Your best bet is to get an old HP8620 or Wiltron 610 sweeper with some plug-ins. They are simple enough to dig into the guts and modify/experiment. These are regular old analog sweepers with no synthesis - look at their specs to see what kind of stability can be expected. Ed ___ 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] PPS offset between GPS receivers
OK, I use the two GPSDOs method because I can set the PPS position but the cable is useful and only one GPSDO (or any other stable PPS source) is enough. On Sat, Dec 8, 2012 at 6:53 PM, Don Latham d...@montana.com wrote: I use a tee connection and terminated 100 foot (33 m )piece of RG58 coax for a known delay to the stop pulse. Don L Azelio Boriani Yes, this is a good test: to evaluate how your preferred uP can perform as a time interval counter, you can hook two GPDSOs' PPS to it and see the result. The best would be to have at hand also a real TIC (HP53132A, PM6681, SR620 or similar) and compare. On Sat, Dec 8, 2012 at 4:28 AM, Bob Camp li...@rtty.us wrote: Hi A lot depends on exactly what the interrupt structure is. It may also depend on the phase of the cpu clock relative to the pps signal. What's reasonably sure is that there is indeed some offset between the two where the answer is indeed ft's random. Another thing to check - how wide is the random region? Bob On Dec 7, 2012, at 9:19 PM, Chris Albertson albertson.ch...@gmail.com wrote: One more test to try. Connect one PPS signal to both GPIO ports and see how close to zero offset you get. It would likely be random which gets read first. On Wed, Dec 5, 2012 at 5:37 AM, Gabs Ricalde gsrica...@gmail.com wrote: Hi everyone, As Tom suggested, I redid the test with less than 1 ft. of wire from the PPS output to the GPIO without any logic gates or line receivers. Same result, the SKG25A1 was 2 microseconds ahead of the 58534A. Without any other way of testing, I would probably trust the output of the timing receiver more than the SkyNav module. Anyway the SkyNav board is an inexpensive unit and I wouldn't mind setting an offset in ntpd. I don't have a scope yet, and a low jitter PPS GPIO is the closest thing I have to a TIC. ___ 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. -- Chris Albertson Redondo Beach, California ___ 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 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 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. De Erroribus Medicorum, R. Bacon, 13th century. If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ 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 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] Nifty MINI TIC for DMTD work please hold off, 4 channel picture attached
What is the status of this project ? I may have missed a few e-mails. Thanks, Dick, W1KSZ On 11/19/2012 2:52 PM, ewkeh...@aol.com wrote: listPlease hold off, tomorrow I will have a detailed description of the total project. Interest seems to be large and soon we will find a way to make it available to every one. Waiting for Juerg my partner in crime to review what I will say tomorrow The 4 channel picture is attached Bert Kehren In a message dated 11/19/2012 4:38:16 P.M. Eastern Standard Time, mspr...@suddenlink.net writes: MINI-TIC for DMTD work Please add me to the list. Thanks Maury Sproul W5UGQ ___ 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 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 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 DO Alternatives
On 12/8/12 9:30 AM, johncr...@aol.com wrote: Instead the discussion has centered on what microprocessor (of a hundred that would work) and how to eliminate glue logic and and a few analog parts to save money. This is silly - silicon is CHEAP. Silicon is cheap, but for one-off fabrication by a hobbyist that isn't always the case. As was mentioned in a couple of the mails in the long discussion, for a single person to build something like this requires a combination of skills and materials. Someone may be fine at software, but doesn't want to fabricate circuitry, or vice versa. So, there was discussion of what could you do that would literally be plug and play with minimal hardware design and assembly required (so the playing would be with software). This isn't an unusual scenario.. The AMSAT folks have run into it vis a vis ground stations. So have others (APRS). A colleague of mine (N5BF) comments that what you really need is something where someone can impulse buy enough to do something useful fairly quickly. The kit idea: buying $100 worth of parts and then having to spend 6 weeks assembling and testing means that lots of people will have $100 parts bags sitting on a shelf, unused. You'd be better off selling a $200 assembled and tested widget. Yes, you won't sell quite as many, but a LOT more of them will be actually used than those bags o'parts. A particularly attractive model is where you have a hardware component that is delivered pretty much ready to go, with basic software, and the fooling around is with changes in the software or parameters. For the GPSDO world, this might be experimenting with different filters and holdover strategies, or maybe tuning it to work with your particular OCXO. This is why the Arduino is so popular. No or minimal soldering required, a wealth of simple software that almost does what you need it to, be it monitoring the temperature of your beer fermentation, turning on and off sprinklers or whatever. Anything where the software is quite complex, that will inhibit experimentation, unless there's a lot of documentation of the theory of operation and software design, and the software has to be written to facilitate modification. For the Arduino, the limited amount of storage sort of self limits the complexity of applications. Once you move into the PC world it gets a lot harder. And realistically, a lot of hobby written software doesn't have a good architecture or underlying design. It sort of just growed in place with successive modifications to add features, etc. And it works, but it's not very easy to figure out how to modify 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] GPS DO Alternatives
I've only been following this thread distantly, however, I have been playing with arduinos quite a bit of late. If you wanted to incorporate one as the processor of choice in a new design, the cost is quite low, under $4.00us for the processor in quantity one. I've used one in a new design in the last week and it really simplified life. As to the capabilities, remember that pretty much any AVR chip can run the arduino code. The atmega128 has more oomph for about the same price for example. Additionally, if you don't like the language for the arduino, C takes about 5 minutes to get running. Bob On Dec 8, 2012, at 17:52, Jim Lux jim...@earthlink.net wrote: On 12/8/12 9:30 AM, johncr...@aol.com wrote: Instead the discussion has centered on what microprocessor (of a hundred that would work) and how to eliminate glue logic and and a few analog parts to save money. This is silly - silicon is CHEAP. Silicon is cheap, but for one-off fabrication by a hobbyist that isn't always the case. As was mentioned in a couple of the mails in the long discussion, for a single person to build something like this requires a combination of skills and materials. Someone may be fine at software, but doesn't want to fabricate circuitry, or vice versa. So, there was discussion of what could you do that would literally be plug and play with minimal hardware design and assembly required (so the playing would be with software). This isn't an unusual scenario.. The AMSAT folks have run into it vis a vis ground stations. So have others (APRS). A colleague of mine (N5BF) comments that what you really need is something where someone can impulse buy enough to do something useful fairly quickly. The kit idea: buying $100 worth of parts and then having to spend 6 weeks assembling and testing means that lots of people will have $100 parts bags sitting on a shelf, unused. You'd be better off selling a $200 assembled and tested widget. Yes, you won't sell quite as many, but a LOT more of them will be actually used than those bags o'parts. A particularly attractive model is where you have a hardware component that is delivered pretty much ready to go, with basic software, and the fooling around is with changes in the software or parameters. For the GPSDO world, this might be experimenting with different filters and holdover strategies, or maybe tuning it to work with your particular OCXO. This is why the Arduino is so popular. No or minimal soldering required, a wealth of simple software that almost does what you need it to, be it monitoring the temperature of your beer fermentation, turning on and off sprinklers or whatever. Anything where the software is quite complex, that will inhibit experimentation, unless there's a lot of documentation of the theory of operation and software design, and the software has to be written to facilitate modification. For the Arduino, the limited amount of storage sort of self limits the complexity of applications. Once you move into the PC world it gets a lot harder. And realistically, a lot of hobby written software doesn't have a good architecture or underlying design. It sort of just growed in place with successive modifications to add features, etc. And it works, but it's not very easy to figure out how to modify 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. ___ 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] YIG oscillator drift question
Yes, something must supply the minimum magnetic field to activate the oscillator - but the current determines the field, so it's necessarily part of the drift characteristic. It also depends on whether the YIG sphere is heated - usually to 80 deg C or so, to help stabilize it. Without any other frequency control, you can expect it to stay within about +/- 10 MHz of the frequency predicted by its tuning curve. It is very linear with magnetic field, hence tuning current, until the core material begins to saturate at high flux levels, so the tuning current needs to be increased to compensate. The most common type is one-octave 2-4 GHz, used in spectrum analyzers from the 1970s on, and also the first microwave band of many generators. Another common one is the 2-6.X GHz also used for the same purposes, but covering a wider direct range. The next bands up are typically 4-8, 6-12, 8-12, and 12-18 GHz, used in generators, at least in older gear. You can expect to find about +10 to +18 dBm output power range, and fairly flat with frequency. The minimum setup is one or two power supplies, plus a variable coil current driver up to one amp or so. You don't need the heater to run it. Don't bother with the FM coil - it's not needed for basic experimenting, and it's easy to burn out if you screw up. The main coil is more robust, but it can be burned out with too much current, so don't go too far beyond the maximum tuning current spec. It can also shock you from inductive kickback, so the coil needs clamping too. It's best study the circuits of existing sweepers and such to get ideas on how it's all done. Your best bet is to get an old HP8620 or Wiltron 610 sweeper with some plug-ins. They are simple enough to dig into the guts and modify/experiment. These are regular old analog sweepers with no synthesis - look at their specs to see what kind of stability can be expected. Ed Ed, thanks for your advices. Accuracy vs tuning current is not an issue for me, but stability does. I should experiment. But I begin to understand that they are orders of magnitude far from even the worst crystals. Antonio I8IOV ___ 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 DO Alternatives
Hi A standard that is good to 8 digits can be done manually. That's far cheaper than your goal and the software is totally open source. It can be done with off the shelf parts and no wiring at all. Problem solved? I suspect not…. Bob On Dec 8, 2012, at 1:59 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sat, Dec 8, 2012 at 9:30 AM, johncr...@aol.com wrote: Hello all - People talk about good deals on Thunderbolts but I have yet to see one. It seems peak Thunderbolt passed before I was seriously looking. *The box you put it in - suspending it above the bench on inspirational thought probably will not work. A nice box is easily $ 50.00 so who cares about adding another flip flop or counter at 25 cents each. The goal, well my goal is to build a GPSDO to this set of requirements 1) well under 1/2 the cost of the t-bolt. 2) can be made with common parts and skills most people have 3) is completely modifiable (open source software) So #1 above means you use a low cost box, perhaps the case and old CDROM was once housed in or maybe you gut and old PC chassis #2 pretty much means you have to keep theparts cound way down. Yes a chip might cost only $1 but as soon as you get more then about three of those 25 cent cips you need a PCB. PCB making is not a common everyday skill so #2 means a way-low parts count #3 means the uP is gong to have to come with a very easy to use and free open source toolchain. Adruino is like that, there are others, but a bare uP chip is not going to work You are right that one way to engineer a product is to first set performance numbers. But another more common way is to first identify a target customer and then set a target price. In this case the target customer is a hobbyist with only basic skills who wants a low cost easy to build GPSDO that has can understand and modify himself. Next with those very hard to meet requirements (low cost, low parts count, simple to build) we can ask if the exected perfomance is good enough What is good enough. I'd say if you could use the GPSDO a a local frequency standard for a counter that has 8 digits you are doing well enough. If you can get to 10 digital it is pretty good -- Chris Albertson Redondo Beach, California ___ 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 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 DO Alternatives
Hi A little math: You can get an OCXO that will do 1x10^-10 per day and has a sub 5x10^-10 temp performance. It's likely that the temperature impact will be minimal in a normal environment. If you are after 1x10^-8, you need to correct roughly every 100 days. That's not anything you need a cpu to handle. Even if you are after 1x10^-9, the aging is likely predictable. A bump every 10 days and a measurement once a month likely does the trick. Still not much of a need for a CPU. For a much easier / cheaper / less work solution - grab a cheap rubidium. Manually set it to ~ 1x10^-11. It will hold your 9 digits for at least a year. With some luck I'll hold 10 digits. Bob On Dec 8, 2012, at 1:59 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sat, Dec 8, 2012 at 9:30 AM, johncr...@aol.com wrote: Hello all - People talk about good deals on Thunderbolts but I have yet to see one. It seems peak Thunderbolt passed before I was seriously looking. *The box you put it in - suspending it above the bench on inspirational thought probably will not work. A nice box is easily $ 50.00 so who cares about adding another flip flop or counter at 25 cents each. The goal, well my goal is to build a GPSDO to this set of requirements 1) well under 1/2 the cost of the t-bolt. 2) can be made with common parts and skills most people have 3) is completely modifiable (open source software) So #1 above means you use a low cost box, perhaps the case and old CDROM was once housed in or maybe you gut and old PC chassis #2 pretty much means you have to keep theparts cound way down. Yes a chip might cost only $1 but as soon as you get more then about three of those 25 cent cips you need a PCB. PCB making is not a common everyday skill so #2 means a way-low parts count #3 means the uP is gong to have to come with a very easy to use and free open source toolchain. Adruino is like that, there are others, but a bare uP chip is not going to work You are right that one way to engineer a product is to first set performance numbers. But another more common way is to first identify a target customer and then set a target price. In this case the target customer is a hobbyist with only basic skills who wants a low cost easy to build GPSDO that has can understand and modify himself. Next with those very hard to meet requirements (low cost, low parts count, simple to build) we can ask if the exected perfomance is good enough What is good enough. I'd say if you could use the GPSDO a a local frequency standard for a counter that has 8 digits you are doing well enough. If you can get to 10 digital it is pretty good -- Chris Albertson Redondo Beach, California ___ 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 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] Help support the microwave addiction.
Hi all! Having finally moved and having been able to sort the stuff, there's some goodies for sale: Do have a few more items that would be of interest to the time and frequency folks, but here's the first two. I have two Shera based gpsdo kits available. One board is built, tested and working. The other is a complete kit of all parts and the A+A engineering pc board. Included in each kit: 1 HP 10811a-60111 1 sma unknown 5v active patch gps L1 antenna 1 HP 58535a gps active splitter 1 Motorola M12+T gps receiver The built kit gets an HP rack mount enclosure with a LCD display of the efc voltage. Feel free to use the boards inside, but as you will see, it was my first attempt at a partial kit where YOU the builder must buy to spec and then integrate according to a plan. Looks like hell. Works ok, though.. Would like to trade for equipment. Particularly microwave attenuators, mixers, preamps. Will trade + cash for a signal generator good to 18 GHz. Kit one (built board with enclosure and power supply. Ask for photos.) $250 Kit two $210 All reasonable offers considered. ___ 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] Help support the microwave addiction.
Hi, May I see pictures of both kits off list please? xe1xus at amsat dot org Thanks. Regards, Edgardo Molina Dirección IPTEL www.iptel.net.mx T : 55 55 55202444 M : 04455 10045822 Piensa en Bits SA de CV Información anexa: CONFIDENCIALIDAD DE INFORMACION Este mensaje tiene carácter confidencial. Si usted no es el destinarario de este mensaje, le suplicamos se lo notifique al remitente mediante un correo electrónico y que borre el presente mensaje y sus anexos de su computadora sin retener una copia de los mismos. Queda estrictamente prohibido copiar este mensaje o hacer usode el para cualquier propósito o divulgar su en forma parcial o total su contenido. Gracias. NON-DISCLOSURE OF INFORMATION This email is strictly confidential and may also be privileged. If you are not the intended recipient please immediately advise the sender by replying to this e-mail and then deleting the message and its attachments from your computer without keeping a copy. It is strictly forbidden to copy it or use it for any purpose or disclose its contents to any third party. Thank you. On Dec 8, 2012, at 6:59 PM, Lizeth Norman normanliz...@gmail.com wrote: Hi all! Having finally moved and having been able to sort the stuff, there's some goodies for sale: Do have a few more items that would be of interest to the time and frequency folks, but here's the first two. I have two Shera based gpsdo kits available. One board is built, tested and working. The other is a complete kit of all parts and the A+A engineering pc board. Included in each kit: 1 HP 10811a-60111 1 sma unknown 5v active patch gps L1 antenna 1 HP 58535a gps active splitter 1 Motorola M12+T gps receiver The built kit gets an HP rack mount enclosure with a LCD display of the efc voltage. Feel free to use the boards inside, but as you will see, it was my first attempt at a partial kit where YOU the builder must buy to spec and then integrate according to a plan. Looks like hell. Works ok, though.. Would like to trade for equipment. Particularly microwave attenuators, mixers, preamps. Will trade + cash for a signal generator good to 18 GHz. Kit one (built board with enclosure and power supply. Ask for photos.) $250 Kit two $210 All reasonable offers considered. ___ 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 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 DO Alternatives
So the goal then is automate the process, not to make it better. I figure once you have an easy-to-modify and easy-to-replicate design up and running then with many people able to experiment the performance will improve. You can almost not count the cost of the Arduino. This is a self contained part that can be used in many projects. Same with a 12VDC power supply. Lots of people like to play with these and have them already. So, as for performance, let's just say for not that it only has to work as well as one could do by hand and eye and a 'scope. Let's say 10E-8 What if I use a flip flop. The PPS from the GPS connects to the set input of the FF and also to the Arduino interrupt. The output of the OCXO goes to the reset pin of the same FF. The interrupt handler reads the value of the FF. It will be either 1 or 0 depending if the phase of the OCXO leads or lags the phase of the PPS. The software will try to keep the FF average value at exactly 0.500 On Sat, Dec 8, 2012 at 4:25 PM, Bob Camp li...@rtty.us wrote: Hi A standard that is good to 8 digits can be done manually. That's far cheaper than your goal and the software is totally open source. It can be done with off the shelf parts and no wiring at all. Problem solved? I suspect not…. Bob On Dec 8, 2012, at 1:59 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sat, Dec 8, 2012 at 9:30 AM, johncr...@aol.com wrote: Hello all - People talk about good deals on Thunderbolts but I have yet to see one. It seems peak Thunderbolt passed before I was seriously looking. *The box you put it in - suspending it above the bench on inspirational thought probably will not work. A nice box is easily $ 50.00 so who cares about adding another flip flop or counter at 25 cents each. The goal, well my goal is to build a GPSDO to this set of requirements 1) well under 1/2 the cost of the t-bolt. 2) can be made with common parts and skills most people have 3) is completely modifiable (open source software) So #1 above means you use a low cost box, perhaps the case and old CDROM was once housed in or maybe you gut and old PC chassis #2 pretty much means you have to keep theparts cound way down. Yes a chip might cost only $1 but as soon as you get more then about three of those 25 cent cips you need a PCB. PCB making is not a common everyday skill so #2 means a way-low parts count #3 means the uP is gong to have to come with a very easy to use and free open source toolchain. Adruino is like that, there are others, but a bare uP chip is not going to work You are right that one way to engineer a product is to first set performance numbers. But another more common way is to first identify a target customer and then set a target price. In this case the target customer is a hobbyist with only basic skills who wants a low cost easy to build GPSDO that has can understand and modify himself. Next with those very hard to meet requirements (low cost, low parts count, simple to build) we can ask if the exected perfomance is good enough What is good enough. I'd say if you could use the GPSDO a a local frequency standard for a counter that has 8 digits you are doing well enough. If you can get to 10 digital it is pretty good -- Chris Albertson Redondo Beach, California ___ 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 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. -- Chris Albertson Redondo Beach, California ___ 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 DO Alternatives
Hi Have an alarm go off on your PC and do the correction once a month. Bob On Dec 8, 2012, at 8:56 PM, Chris Albertson albertson.ch...@gmail.com wrote: So the goal then is automate the process, not to make it better. I figure once you have an easy-to-modify and easy-to-replicate design up and running then with many people able to experiment the performance will improve. You can almost not count the cost of the Arduino. This is a self contained part that can be used in many projects. Same with a 12VDC power supply. Lots of people like to play with these and have them already. So, as for performance, let's just say for not that it only has to work as well as one could do by hand and eye and a 'scope. Let's say 10E-8 What if I use a flip flop. The PPS from the GPS connects to the set input of the FF and also to the Arduino interrupt. The output of the OCXO goes to the reset pin of the same FF. The interrupt handler reads the value of the FF. It will be either 1 or 0 depending if the phase of the OCXO leads or lags the phase of the PPS. The software will try to keep the FF average value at exactly 0.500 On Sat, Dec 8, 2012 at 4:25 PM, Bob Camp li...@rtty.us wrote: Hi A standard that is good to 8 digits can be done manually. That's far cheaper than your goal and the software is totally open source. It can be done with off the shelf parts and no wiring at all. Problem solved? I suspect not…. Bob On Dec 8, 2012, at 1:59 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sat, Dec 8, 2012 at 9:30 AM, johncr...@aol.com wrote: Hello all - People talk about good deals on Thunderbolts but I have yet to see one. It seems peak Thunderbolt passed before I was seriously looking. *The box you put it in - suspending it above the bench on inspirational thought probably will not work. A nice box is easily $ 50.00 so who cares about adding another flip flop or counter at 25 cents each. The goal, well my goal is to build a GPSDO to this set of requirements 1) well under 1/2 the cost of the t-bolt. 2) can be made with common parts and skills most people have 3) is completely modifiable (open source software) So #1 above means you use a low cost box, perhaps the case and old CDROM was once housed in or maybe you gut and old PC chassis #2 pretty much means you have to keep theparts cound way down. Yes a chip might cost only $1 but as soon as you get more then about three of those 25 cent cips you need a PCB. PCB making is not a common everyday skill so #2 means a way-low parts count #3 means the uP is gong to have to come with a very easy to use and free open source toolchain. Adruino is like that, there are others, but a bare uP chip is not going to work You are right that one way to engineer a product is to first set performance numbers. But another more common way is to first identify a target customer and then set a target price. In this case the target customer is a hobbyist with only basic skills who wants a low cost easy to build GPSDO that has can understand and modify himself. Next with those very hard to meet requirements (low cost, low parts count, simple to build) we can ask if the exected perfomance is good enough What is good enough. I'd say if you could use the GPSDO a a local frequency standard for a counter that has 8 digits you are doing well enough. If you can get to 10 digital it is pretty good -- Chris Albertson Redondo Beach, California ___ 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 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. -- Chris Albertson Redondo Beach, California ___ 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 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 DO Alternatives
Hi Here's the easy way: Feed the GPS and the PPS from the OCXO into NTP. Let it discipline to the GPS and simply monitor the OCXO. That will give you all the time data you would ever need. Once a month / week run a script to steer the OCXO by the error divided by X. Play with X and you can optimize the process. Bob On Dec 8, 2012, at 8:59 PM, Bob Camp li...@rtty.us wrote: Hi Have an alarm go off on your PC and do the correction once a month. Bob On Dec 8, 2012, at 8:56 PM, Chris Albertson albertson.ch...@gmail.com wrote: So the goal then is automate the process, not to make it better. I figure once you have an easy-to-modify and easy-to-replicate design up and running then with many people able to experiment the performance will improve. You can almost not count the cost of the Arduino. This is a self contained part that can be used in many projects. Same with a 12VDC power supply. Lots of people like to play with these and have them already. So, as for performance, let's just say for not that it only has to work as well as one could do by hand and eye and a 'scope. Let's say 10E-8 What if I use a flip flop. The PPS from the GPS connects to the set input of the FF and also to the Arduino interrupt. The output of the OCXO goes to the reset pin of the same FF. The interrupt handler reads the value of the FF. It will be either 1 or 0 depending if the phase of the OCXO leads or lags the phase of the PPS. The software will try to keep the FF average value at exactly 0.500 On Sat, Dec 8, 2012 at 4:25 PM, Bob Camp li...@rtty.us wrote: Hi A standard that is good to 8 digits can be done manually. That's far cheaper than your goal and the software is totally open source. It can be done with off the shelf parts and no wiring at all. Problem solved? I suspect not…. Bob On Dec 8, 2012, at 1:59 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Sat, Dec 8, 2012 at 9:30 AM, johncr...@aol.com wrote: Hello all - People talk about good deals on Thunderbolts but I have yet to see one. It seems peak Thunderbolt passed before I was seriously looking. *The box you put it in - suspending it above the bench on inspirational thought probably will not work. A nice box is easily $ 50.00 so who cares about adding another flip flop or counter at 25 cents each. The goal, well my goal is to build a GPSDO to this set of requirements 1) well under 1/2 the cost of the t-bolt. 2) can be made with common parts and skills most people have 3) is completely modifiable (open source software) So #1 above means you use a low cost box, perhaps the case and old CDROM was once housed in or maybe you gut and old PC chassis #2 pretty much means you have to keep theparts cound way down. Yes a chip might cost only $1 but as soon as you get more then about three of those 25 cent cips you need a PCB. PCB making is not a common everyday skill so #2 means a way-low parts count #3 means the uP is gong to have to come with a very easy to use and free open source toolchain. Adruino is like that, there are others, but a bare uP chip is not going to work You are right that one way to engineer a product is to first set performance numbers. But another more common way is to first identify a target customer and then set a target price. In this case the target customer is a hobbyist with only basic skills who wants a low cost easy to build GPSDO that has can understand and modify himself. Next with those very hard to meet requirements (low cost, low parts count, simple to build) we can ask if the exected perfomance is good enough What is good enough. I'd say if you could use the GPSDO a a local frequency standard for a counter that has 8 digits you are doing well enough. If you can get to 10 digital it is pretty good -- Chris Albertson Redondo Beach, California ___ 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 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. -- Chris Albertson Redondo Beach, California ___ 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 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 mailing list -- time-nuts@febo.com To unsubscribe, go to
Re: [time-nuts] GPS DO Alternatives
Bob, Charles, Chris, If the goal is a GPS locked frequency counter then there is no need for disciplining the LO at all. Just let the XO or OCXO or Rb free-run. Use a two channel counter: one capture input to measure the frequency of the DUT and another capture input to leisurely and independently monitor the 1PPS. Over time the counter will know the frequency error (and drift) rate of the LO relative to GPS, which it then applies as a *math* correction to all DUT frequency readings before the user sees them. I do this all the time -- an XO-based picPET measuring a GPS 1PPS is really measuring the XO using GPS, not the other way around. It takes one line of code to apply a *(1+e) correction to a reading. The averaging interval over which e is calculated replaces the GPSDO time constant. Effectively you are disciplining the readings rather than the oscillator. No DAC used. This also allows you to use oscillators that lack EFC. The LO doesn't need to be a nice number like 10 MHz either. Saving e in EEPROM is effectively holdover mode. This GPSDFC is simpler than a GPSDO-frequency counter but delivers the same accuracy. Note any stable 1PPS source will do; doesn't have to be GPS. The quality of the LO determines the short gate time stability. The accuracy of the 1PPS determines the long gate time accuracy. /tvb ___ 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] YIG oscillator drift question
Another thing you should be aware of is that they have quite a bit of hysteresis - so even with the same tuning current the output frequency might differ by several MHz depending on whether you approached that setpoint from above or below. The YIG sphere also has a substantial temperature coefficient - so although you don't *need* the heater in order to get the oscillator working not having it will substantially degrade your frequency stability. On Sun, Dec 9, 2012 at 6:45 AM, iov...@inwind.it iov...@inwind.it wrote: Yes, something must supply the minimum magnetic field to activate the oscillator - but the current determines the field, so it's necessarily part of the drift characteristic. It also depends on whether the YIG sphere is heated - usually to 80 deg C or so, to help stabilize it. Without any other frequency control, you can expect it to stay within about +/- 10 MHz of the frequency predicted by its tuning curve. It is very linear with magnetic field, hence tuning current, until the core material begins to saturate at high flux levels, so the tuning current needs to be increased to compensate. The most common type is one-octave 2-4 GHz, used in spectrum analyzers from the 1970s on, and also the first microwave band of many generators. Another common one is the 2-6.X GHz also used for the same purposes, but covering a wider direct range. The next bands up are typically 4-8, 6-12, 8-12, and 12-18 GHz, used in generators, at least in older gear. You can expect to find about +10 to +18 dBm output power range, and fairly flat with frequency. The minimum setup is one or two power supplies, plus a variable coil current driver up to one amp or so. You don't need the heater to run it. Don't bother with the FM coil - it's not needed for basic experimenting, and it's easy to burn out if you screw up. The main coil is more robust, but it can be burned out with too much current, so don't go too far beyond the maximum tuning current spec. It can also shock you from inductive kickback, so the coil needs clamping too. It's best study the circuits of existing sweepers and such to get ideas on how it's all done. Your best bet is to get an old HP8620 or Wiltron 610 sweeper with some plug-ins. They are simple enough to dig into the guts and modify/experiment. These are regular old analog sweepers with no synthesis - look at their specs to see what kind of stability can be expected. Ed Ed, thanks for your advices. Accuracy vs tuning current is not an issue for me, but stability does. I should experiment. But I begin to understand that they are orders of magnitude far from even the worst crystals. Antonio I8IOV ___ 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 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] For Arduino lovers and haters
I'm posting this seemingly off topic information, because many times a Time Nut needs to do something with a microcontroller (witness the recent discussion about GPSDO's). Sometimes, you just want to throw something together for a quick test or for a temporary project... I have never used an Arduino, but I see them mentioned all the time, with numerous projects and code posted on the net. A while back, I did pick up a few MSP430 Launchpads, as they were so inexpensive. I started teaching myself C, but kept getting sidetracked with other things. In any event, the simplified C-style of an Arduino program, and the huge quantity of code out there is attractive. What does Arduino have to do with the MSP430 Launchpad? Well, a few guys ported the Arduino IDE to the launchpad. The project is called Energia and is found here: http://energia.nu/ With some minor pin remapping, many Arduino programs (I won't call them sketches) can be run on the Launchpad. Considering that the Launchpad is $4.30 (with free shipping) and an Arduino board is several times that, it makes the Launchpad even more attractive. Of course, you don't have the Arduino addon boards (shields) with the Launchpad, but you may not need all that for a particular project. One item of particular note - the Energia IDE was just updated to include the new TI Stellaris Launchpad. This is a very powerful ARM Cortex board that costs very little. I got two for $5 each with free shipping, on a pre-release special deal. As an example of just getting something done without reinventing the wheel, I just got in one of those AD9851 DDS modules that you find online from China. For now, I just wanted to make sure that the module worked (I have a particular use for it later). I quickly found an Arduino program online that uses the same DDS module. All it took was some pin remapping to make it work with the MSP430 Launchpad and the Energia IDE. I was able to quickly verify that the DDS module works just fine. Sorry for the long winded post, but I thought some here would find this information of use. Eventually, I'll get back to learning C. Right now, the project I'm doing requires me to learn Python :-) Joe Gray W5JG ___ 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 DO Alternatives
albertson.ch...@gmail.com said: What if I use a flip flop. The PPS from the GPS connects to the set input of the FF and also to the Arduino interrupt. The output of the OCXO goes to the reset pin of the same FF. I don't think that is going to do what you want. The problem is what happens if set and reset are on at the same time? If I was doing that, I'm make the PPS from the OCXO 50% duty cycle and use the PPS from the GPS as a clock with the PPS from the OCXO as the data input. Which brings up another worm for the can. How are you going to get a PPS from the OCXO? That's going to be hard without some soldering. My straw man would be to use the OCXO to clock whatever uP you end up using and generate the PPS with a counter/timer. An alternative would be 7 TTL chips or a CPLD/FLGA. -- These are my opinions. I hate spam. ___ 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] Help support the microwave addiction.
Pictures at: http://www.flickr.com/photos/n3ykf/ ___ 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.
