Re: [time-nuts] 1pps to 10khz PIC stuff
Hi Ashley, Reading between the lines, are you trying to subsitute a 1pps output GPS for use in the G3RUH 10kHz GPSDO design? If this is the case youwould be better off biting the bullet and going for a design that uses 1pps directly. An example is the classic Brooks Shera design, http://www.rt66.com/~shera/index_fs.htm While it's simple to build, there are limitations to the G3RUH design. Adding extra circuitry to generate the 10kHz is most likely to degrade the perfomance. A good overview of GPSDO's can be found here, http://www.ko4bb.com/Timing/FrequencyReference.php Timing grade Motorola Oncore GPS's are availble cheaply on ebay. Regards, Robert G8RPI. --- On Mon, 22/2/10, ashle...@aol.com ashle...@aol.com wrote: From: ashle...@aol.com ashle...@aol.com Subject: [time-nuts] 1pps to 10khz PIC stuff To: time-nuts@febo.com Date: Monday, 22 February, 2010, 2:13 Hi.has anyone experiemented with programming a PIC to get 10khz out of 1pps GPS pulses ? If so, maybe a link or two please , or some info . Thanks Thank You Kiss-Electronics Ms Ashley Hall 183 N 5th Avenue Cornelius, Oregon 97113 W7DUZ www.kiss-electronics.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.
[time-nuts] 24th European Frequency and Time Forum, 13-16 April 2010
All, This years European TF Forum is being held at ESA-ESTEC in Noordwijk in the Netherlands. Rob Kimberley _ Dear colleague, We are pleased to announce that the programme for the 24th European Frequency and Time Forum, being held 13-16 April 2010 at ESA-ESTEC, The Netherlands, has been published. Please visit the website at http://www.eftf2010.org www.eftf2010.org where you can see all details of the conference programme. One of the novelties of EFTF 2010 is the introduction of Tutorials on topics related to Time and Frequency technologies, techniques and applications. Tutorials will be held on Monday 12 April 2010, the day preceding the beginning of the conference. A visit of the ESTEC Laboratories and Space Facilities will be organised on Friday, April 16th. For registration, the online registration form available at the website http://www.eftf2010.org www.eftf2010.org can be used. Please note that the deadline for the early registration fee is 15 March 2010. We are looking forward to your participation and to welcoming you at ESTEC. With kind regards, On behalf of the organisers, ESA Conference Bureau ___ 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-nuts Digest, Vol 67, Issue 142
Hi.. If the price is right, the 8590 analyzer if healthy makes a good introduction to that class of instruments, you'll learn a lot. Yes, they are not the top of the range, but they are not shabby either. Get yourself signed up to the HP_Agilent group (also on Yahoo) for detailed info, and they are not too dificult to fix either. There is a lithium backup battery that perhaps should be replaced if there is no evidence it has already been done, but look up the correct procedure before you go wading in. Re dim traces/screens. The faceplate protector often gets crudded up on the inside, making things darker than you'd think. Bit of a task to remove and clean, but not dificult. Manuals are available if you ask in the right places. Again, ask before getting the toolbox out. It's also relativley trivial to make a crude converter to get up to 3GHz. In essance, all you need is a stable oscilator, a mixer, and perhaps a crude band pass filter. Not calibrated but you'll see stuff that can help whatever you are trying to do. The choice of frequencies is the interesting bit, avoiding any posible IF leakage, and knowing how to identify (and ignore) images etc. As to usability, bit of a mixed bag. They can be easy to drive, but there are layers of menus too. However, once you find your way round them, no problem. As it has GPIB, look at KE5FX's GPIB software tools for sa's. Very good indeed. As above, if the price is right, get it. A good first SA to own. But see it working first, even if it's just looking at the local broacast FM stations with a bit of wire in the front input socket. No signals (especialy if no 0Hz spur = no buy, unless the price is very very very low, even then, it may just end up as a parts donor.) Dave G0WBX. Original Message Message: 1 Date: Fri, 19 Feb 2010 17:38:50 -0700 From: Joseph Gray jg...@zianet.com Subject: [time-nuts] OT: HP 8590A To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: c793a5fe1002191638j24a8913dnad62d8800dee3...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 Since the list members are familiar with lots of test equipment, I'd like to ask what the folks here think about the HP 8590A Spectrum Analyzer. Is this model ok? Are there any particular failures I should be aware of in this 20+ year old equipment? I have a chance to buy one locally. The only option is has is GPIB. I took a preliminary look at it and it passes the simple test/cal procedure from chapter 1 of the Ops manual. This model only goes to 1.5GHz, but would still be useful for Amateur use. I do wish it would go up to 3GHz, however. I have never owned a spec an, but am somewhat familiar with their usage. Thanks for the input. Joe KA5ZEC ___ 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] Are the days of buying a crystal numbered?
Hi All, Found this interesting device last week while looking for a basic PLL to replace a crystal for an IF offset. Has anyone experimented with the si570/si571 yet? www.silabs.com/Support%20Documents/TechnicalDocs/ http://www.silabs.com/Support%20Documents/TechnicalDocs/Si570.pdf Si570.pdf Regards Gerald VK3GJM ___ 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] Are the days of buying a crystal numbered?
I built a kit and found that it wanders 50 Hz at 10MHz. http://www.cliftonlaboratories.com/si570_kit_from_k5bcq.htm Found this interesting device last week while looking for a basic PLL to replace a crystal for an IF offset. Has anyone experimented with the si570/si571 yet? www.silabs.com/Support%20Documents/TechnicalDocs/ http://www.silabs.com/Support%20Documents/TechnicalDocs/Si570.pdf Si570.pdf Regards Gerald VK3GJM -- Raj, VU2ZAP Bangalore, India. ___ 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] Are the days of buying a crystal numbered?
It's a very good device. Used in 1000's of Softrock SDR's arround the world now. Control software (by various means, including USB) can be found courtesy of the Softrock40 group, on Yahoo. http://groups.yahoo.com/group/softrock40/ 73. Dave G0WBX. -- Message: 6 Date: Mon, 22 Feb 2010 21:59:44 +1100 From: Gerald Molenkamp gera...@commtelns.com Subject: [time-nuts] Are the days of buying a crystal numbered? To: time-nuts@febo.com Message-ID: 50d403a38069bf4196f41887738c03ee544...@companyweb Content-Type: text/plain; charset=us-ascii Hi All, Found this interesting device last week while looking for a basic PLL to replace a crystal for an IF offset. Has anyone experimented with the si570/si571 yet? www.silabs.com/Support%20Documents/TechnicalDocs/ http://www.silabs.com/Support%20Documents/TechnicalDocs/Si570.pdf Si570.pdf Regards Gerald VK3GJM ___ 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] OCXO info?
Hi A picture of the end with the markings on it would be a big help. It looks a lot like a late 50's / early 60's design. I would not count on it's performance being real good by todays standards. Bob On Feb 21, 2010, at 11:18 PM, Larry Snyder wrote: Hi all -- Looking for any docs on a military (US) OCXO that I believe was an option in a transceiver. It's about 2X3X4.5 inches and if I remember correctly, supplied 5 MHz to the box it was installed in. Here's a photo with the identifying marks: http://teamlarry.com/ocxo.jpg I'd like to see if it might be a candidate for GPS disciplining. thanx! -ls- ___ 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] Jupiter GPS Receivers, ( V1.80)
Hi to the list Anyone out there in Time Nuts Land have a working Jupiter receiver (V1.80) or newer they are not currently using and would like to trade for $$ ? Thanks !! Thank You Kiss-Electronics Ms Ashley Hall 183 N 5th Avenue Cornelius, Oregon 97113 W7DUZ www.kiss-electronics.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] Are the days of buying a crystal numbered?
Anybody know what its performance is like under vibration? Henry On Mon, Feb 22, 2010 at 5:32 AM, Marco IK1ODO -2 ik1...@spin-it.com wrote: There are several kits around using the Si570 serires of oscillators. I built the FA-SY and it's very nice: http://www.funkamateur.de/download-files/dl1fac_FA-SY-Umbau.pdf FA-SY includes a program to trum the frequency, and a simple oven to heat the oscillator. It stays in some parts in 10^9, and is spectrally very clean. I expected it to be much worse :-) - I may post some plots, if anyone is interested. Then see http://www.mydarc.de/dg8saq/SI570/index.shtml and http://www.sdr-kits.net/USB/USB_Description.html 73 - Marco IK1ODO ___ 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. -- Henry Hallam Sent from my Laptop ___ 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] OCXO info?
Hi Assuming it's an R1051 standard you then have to know who made it. Some of the later parts made by the replacement parts empire were of questionable performance / reliability. The side with the markings likely would tell us a lot. Simple answer - when it's not Chinese New Year, the auction sites are full of $20 OCXO's (including shipping) that will do a *lot* better. If you are patient, you likely can get below $10. How they can do that with shipping is a total mystery. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Arthur Dent Sent: Monday, February 22, 2010 10:12 AM To: time-nuts@febo.com Subject: [time-nuts] OCXO info? It looks like the 5Mhz frequency standard module from a R-1051 receiver. You might find info on it here. http://www.jamminpower.com/main/r1051.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. ___ 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] Are the days of buying a crystal numbered?
From: Henry Hallam he...@pericynthion.org Subject: Re: [time-nuts] Are the days of buying a crystal numbered? Anybody know what its performance is like under vibration? Henry Just guessing here . . . poor Unless it is a specifically G-hardened device, it is sure to be microphonic. All crystals are. G-hardened is just somewhat better. Clay ___ 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] Advice on 10 MHz isolation/distribution (Bob Camp)
Hello Bob, My 15mA estimate for the output stage was based on AC coupling the output, which is how I connected it. The IC is then sourcing 25mA into 100R for half the time and sinking 25mA the rest of the time, so the mean supply current drawn is 12.5mA. The extra is to allow for the IC's dissipation capacitance x 5V x 10MHz. As I was just doing this as a feasibility check, the 74AC163 was on a board on its own, powered from a linear bench supply with loads of RC filtering plus local decoupling, so no problem with interaction with other components. The input was biased to half the supply voltage, and AC coupled to the oscillator which gave ~18dBm sine wave into 50R. Slew rate wasn't much of an issue as it was being driven at 100MHz. Garry Hi Yup, that works. A couple of *very* minor points: - My guess is that your output stage will be pulling a bit more than 15 ma. This assumes you are running a 50 ohm load and a 50 ohm output impedance to deliver 13 dbm (~ 2.5 V p-p). More or less, 100 ohms from +5 to ground would be 50 ma half the time. The stage likely will pull 25 or more ma. (Says Bob who hopefully hasn't done any typos in the last minute or so). You might also want to parallel two (or more) gates to get the output current into the safe region. The Datum LPRO manual on page 18 shows some data for AC gates driven with very simple circuits (just bias the gate ...). The data they show would be adequate for the proposed application (if I remember the numbers right). Power supply bypassing is indeed an issue no matter how you do this. AC gates create some *major* supply line spikes. Depending on how you look at ground bounce, it might be an issue in terms of isolation. Good layout practices required The gate approach also lets you generate an almost differential signal without a lot of crazy effort. One 74AC86 should do the trick. Not real sure that Clay is a big fan of lots of harmonics or of filters. Bob Pascall Electronics Ltd - Registered in England No: 1316674 VAT Registration No: GB 448705134 Registered Office: Brunswick Road, Cobbs Wood, Ashford, Kent, TN23 1EH The transfer of any controlled technology contained in or attached to this email is covered by the Open General Export Licence (Technology for Military Goods), granted by the United Kingdom Secretary of State. The information contained in this email is provided as a personal communication of the sender and, as such, is not binding on Pascall Electronics Ltd. unless the intended recipient has been notified by signed postal or fax communication that the sender is authorised to commit Pascall Electronics Ltd. on the subject matter concerned.The contents of this email are confidential to the intended recipient at the email address to which it has been addressed. It may not be disclosed to or used by anyone other than this addressee, nor may it be copied in any way. If received in error, please contact Oli Poole, at opo...@pascall.co.uk, quoting the name of the sender and the addressee and then delete it from your system. ___ 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] OCXO info?
Yes, it is the R-1051 frequency standard, I have one. It was made by General Dynamics, and was rated, if I recall, at 1x10E-8 per day. See also this archive at http://www.mail-archive.com/time-nuts@febo.com/msg02674.html Antonio I8IOV Messaggio originale Da: li...@cq.nu Data: 22/02/2010 18.17 A: Discussion of precise time and frequency measurementtime-nuts@febo.com Ogg: Re: [time-nuts] OCXO info? Hi Assuming it's an R1051 standard you then have to know who made it. Some of the later parts made by the replacement parts empire were of questionable performance / reliability. The side with the markings likely would tell us a lot. Simple answer - when it's not Chinese New Year, the auction sites are full of $20 OCXO's (including shipping) that will do a *lot* better. If you are patient, you likely can get below $10. How they can do that with shipping is a total mystery. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Arthur Dent Sent: Monday, February 22, 2010 10:12 AM To: time-nuts@febo.com Subject: [time-nuts] OCXO info? It looks like the 5Mhz frequency standard module from a R-1051 receiver. You might find info on it here. http://www.jamminpower.com/main/r1051.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. ___ 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] OCXO info?
Bob Camp li...@cq.nu wrote: Hi Assuming it's an R1051 standard you then have to know who made it. Some of the later parts made by the replacement parts empire were of questionable performance / reliability. The side with the markings likely would tell us a lot. That was the side with the markings, such as it is. CAGE # comes back to 'Target Corporation', so aftermarket spares? And yes, it is certainly from/for an R1051. Simple answer - when it's not Chinese New Year, the auction sites are full of $20 OCXO's (including shipping) that will do a *lot* better. If you are patient, you likely can get below $10. How they can do that with shipping is a total mystery. I'm looking to cheaply upgrade an early non-oven Miller GPSDO. Looking at the schematic, there's no native way to pull this guy. I can wait for the CNY festivities to wind down. :) Thanks Bob Arthur! -ls- ___ 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] 5370A upgraded to 5370B ?
Last week I bought a very clean 5370B, in near new condition (missing OCXO but I have a spare one). It has a HP tag on the top edge of the rear frame, under the top cover, which says: Date 12 09 97 5370A to 5370B by 28457 The serial number is 2116A01177. The front panel template is marked 5370B. I understand that it was a 5370A factory upgraded to B, and I'm wondering if such an upgrade might have been requested by the customer (Digital in the case) and why, or the item was a resurfaced old stock, just sold after the upgrade. Any idea? Messaggio originale Da: iov...@inwind.it Data: 22/02/2010 20.47 A: time-nuts@febo.com Ogg: Re: [time-nuts] OCXO info? Yes, it is the R-1051 frequency standard, I have one. It was made by General Dynamics, and was rated, if I recall, at 1x10E-8 per day. See also this archive at http://www.mail-archive.com/time-nuts@febo.com/msg02674.html Antonio I8IOV Messaggio originale Da: li...@cq.nu Data: 22/02/2010 18.17 A: Discussion of precise time and frequency measurementtime-n...@febo. com Ogg: Re: [time-nuts] OCXO info? Hi Assuming it's an R1051 standard you then have to know who made it. Some of the later parts made by the replacement parts empire were of questionable performance / reliability. The side with the markings likely would tell us a lot. Simple answer - when it's not Chinese New Year, the auction sites are full of $20 OCXO's (including shipping) that will do a *lot* better. If you are patient, you likely can get below $10. How they can do that with shipping is a total mystery. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Arthur Dent Sent: Monday, February 22, 2010 10:12 AM To: time-nuts@febo.com Subject: [time-nuts] OCXO info? It looks like the 5Mhz frequency standard module from a R-1051 receiver. You might find info on it here. http://www.jamminpower.com/main/r1051.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. ___ 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] 5370A upgraded to 5370B ?
I apologize for having left some unwanted quoted text in my previous post. 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] Are the days of buying a crystal numbered?
The trick of including a PLL in an oscillator package has been around for a while. The initial ones were programmed at the factory or distributor. The idea was to avoid the long wait while they polished the crystal to your specific frequency. They stocked them in a handful of frequencies and programmed the right one when they got your order. Early ones had a bad reputation due to lots of jitter. These look good to me. (But I don't work in this area so maybe their marketing stuff fooled me.) This is time-nuts. What is good for one application will be useless for another. Spurs might be a problem, it depends on your application and the exact numbers of the target frequency and the crystal frequency. -- These are my opinions, not necessarily my employer's. 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] TimeKeeper?
Le 22/02/2010 03:02, Alexander Sack a écrit : Has anyone seen this: http://www.drdobbs.com/linux-open-source/223000197;jsessionid=LEYQTVQD4D24TQE1GHPCKH4ATMY32JVN?pgno=1 Excuse if its been talked about but I don't see it in my mail archives. I thought some of the ntpd'ers on this list might be interested. -aps ___ 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. Am I cynical in thinking that the article is just product sales pitch? The writer has not been objective in using realistic NTP configurations and practices by taking the worst case , where neither the local oscillator drift is known (deleting the drift file)nor the local clock value at NTP startup is near reality (deliberate offset ). No one is going to either remove their drift file without good reason, nor allow arbitrairy local clock values at startup. That said NTP is very conservative in validating the stability of clock sources. I have not delved into the code, but it is obvious that even a refclock like a GPS receiver doesn't get any favours. Why should it? Who knows whether the clock is dodgy or not? However the times he was reporting for the offsets to drop to less than 1ms did look excessive. Anyway, just to see if I was seeing a similar profile, I did a stop/start on a Soekris server/client pair . I don't have the same software/hardware config but that shouldn't make a huge difference. ntp is 4.2.0 on FreeBSD 6.2 no fancy hardware. Motorola Oncore UT+ on COM2 reset server conf to sample JUST its UT+ PPS receiver. using the oncore driver out of the box. stopped daemons backed up then removed the /etc/ntp/drift file removed all the loopstat/peerstat logs shifted the system clock down 500ms on both client and server restarted the server daemon wait 30s restart the client daemon Then checked how long client / server got back to a 1ms offset From this test it took the server approx 600secs to get to an offset less than 1ms. The client, started 30secs after the server was sync'd to the same offset shortly afterwards. Not brilliant, but not as bad as those stats shown in the article for linux. I then did a restart with the original drift files and a clock estimate from ntpdate directed at NIST. This is a more realistic event. since even in the event of a system crash, that data is available. Even then, it is a bit unusual for both client and server to be restarted at the same time. In this case, the ntp server was serving with an offset of less than 1ms after 2 mins and the client sync'd just about as fast. So in more realistic ;), one refclock scenario NTP can still get down to a reasonable accuracy in good time after a restart and in a similar timeframe to Timekeeper. ___ 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] TimeKeeper?
That said NTP is very conservative in validating the stability of clock sources. I have not delved into the code, but it is obvious that even a refclock like a GPS receiver doesn't get any favours. Why should it? Who knows whether the clock is dodgy or not? The NMEA strings from low cost GPS units have a lot of noise/jitter. In particular, the SiRF units are horrible. (They are also low cost and widely available.) The time offset has a sawtooth pattern with a long time constant that would be nasty to filter out. Think of hanging bridges. http://www.megapathdsl.net/~hmurray/ntp/GPSSiRF-off.gif However the times he was reporting for the offsets to drop to less than 1ms did look excessive. I've seen lots of comments about ntpd being slow to converge. I haven't investigated carefully, but they seem credible. One way to get in trouble is to have a bad drift file. You can get that if you have a warm system, shut it down, wait for it to cool off, then restart it. -- These are my opinions, not necessarily my employer's. 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] Jupiter GPS Receivers, ( V1.80)
I forgot what your goal was, but if you just want an accurate 10 MHz / 1 pps reference, why not just buy a Thunderbolt or Z3805A? Many on this list have had good results dealing with fluke.l on ebay. I just did a search (select 'advanced search' and put fluke.l in the seller field down the page) and he has several Tbolts starting at $150 and at least one Z3805A at $350. Seems to me you'll get instant gratification and probably better results than with a Jupiter receiver. Or you can search on thunderbolt or Z3805A. There are probably other sellers - I only looked at fluke.l's listings. BTW, in the name fluke.l, the letter after the '.' is lower case L, not one (as has been mistyped on recent postings.) Unless you enjoy the challenge of reinventing this GPS-timing wheel, I'd suggest buying one of these reasonably priced units. -Rex ashle...@aol.com wrote: Hi to the list Anyone out there in Time Nuts Land have a working Jupiter receiver (V1.80) or newer they are not currently using and would like to trade for $$ ? Thanks !! Thank You Kiss-Electronics Ms Ashley Hall 183 N 5th Avenue Cornelius, Oregon 97113 W7DUZ www.kiss-electronics.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] Days of buying crystals numbered...??
Hello, Time-Nutters-- I am in need of a 110 MHz VCXO for a mixer input to provide the needed offset for a tracking generator I am building for my Tek 494P Spectrum Analyzer. The 110 MHz VCXO only needs to be pullable/pushable by +/- 100KHz in order to center the tracking gen signal in the passband of the spectrum analyzer. So-- here is the question: Can programmable oscillators such as the Silicon Labs Si570/571 be configured to be pullable/pushable so as to serve as a stand-alone VCXO...? It would appear that phase noise requirements are very loose for this particular application. Any thoughts on this? Thanks!! Mike Baker -- ___ 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] TimeKeeper?
Hi If the objective is convergence to 1 ms any timing optimized gps receiver will do just fine. Non-timing receivers are going to do all sorts of bizarre things every so often. I don't think we can blame this all on the GPS. The NTP setup he's running in the article is broken. Setting the proper time offset for the GPS you have is part of basic configuration. He alludes to several other setup issues in his distribution. NTP is deliberately damped when things are messed up. Looking at the data, Timekeeper is going to do some really strange things when varying asymmetric delays are involved. That's what NTP is trying to *not* do Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Monday, February 22, 2010 5:03 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] TimeKeeper? That said NTP is very conservative in validating the stability of clock sources. I have not delved into the code, but it is obvious that even a refclock like a GPS receiver doesn't get any favours. Why should it? Who knows whether the clock is dodgy or not? The NMEA strings from low cost GPS units have a lot of noise/jitter. In particular, the SiRF units are horrible. (They are also low cost and widely available.) The time offset has a sawtooth pattern with a long time constant that would be nasty to filter out. Think of hanging bridges. http://www.megapathdsl.net/~hmurray/ntp/GPSSiRF-off.gif However the times he was reporting for the offsets to drop to less than 1ms did look excessive. I've seen lots of comments about ntpd being slow to converge. I haven't investigated carefully, but they seem credible. One way to get in trouble is to have a bad drift file. You can get that if you have a warm system, shut it down, wait for it to cool off, then restart it. -- These are my opinions, not necessarily my employer's. 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. ___ 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] TimeKeeper?
Just to add a little fuel...Did I count the leading zeros incorrectly? He often stated Timekeeper was better than 1 uSec, yet many of his graphs were 10 uSec per division, and he barely made that. Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Monday, February 22, 2010 5:22 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] TimeKeeper? Hi If the objective is convergence to 1 ms any timing optimized gps receiver will do just fine. Non-timing receivers are going to do all sorts of bizarre things every so often. I don't think we can blame this all on the GPS. The NTP setup he's running in the article is broken. Setting the proper time offset for the GPS you have is part of basic configuration. He alludes to several other setup issues in his distribution. NTP is deliberately damped when things are messed up. Looking at the data, Timekeeper is going to do some really strange things when varying asymmetric delays are involved. That's what NTP is trying to *not* do Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Monday, February 22, 2010 5:03 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] TimeKeeper? That said NTP is very conservative in validating the stability of clock sources. I have not delved into the code, but it is obvious that even a refclock like a GPS receiver doesn't get any favours. Why should it? Who knows whether the clock is dodgy or not? The NMEA strings from low cost GPS units have a lot of noise/jitter. In particular, the SiRF units are horrible. (They are also low cost and widely available.) The time offset has a sawtooth pattern with a long time constant that would be nasty to filter out. Think of hanging bridges. http://www.megapathdsl.net/~hmurray/ntp/GPSSiRF-off.gif However the times he was reporting for the offsets to drop to less than 1ms did look excessive. I've seen lots of comments about ntpd being slow to converge. I haven't investigated carefully, but they seem credible. One way to get in trouble is to have a bad drift file. You can get that if you have a warm system, shut it down, wait for it to cool off, then restart it. -- These are my opinions, not necessarily my employer's. 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. ___ 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] Are the days of buying a crystal numbered?
Hal Murray wrote: The trick of including a PLL in an oscillator package has been around for a while. The initial ones were programmed at the factory or distributor. The idea was to avoid the long wait while they polished the crystal to your specific frequency. They stocked them in a handful of frequencies and programmed the right one when they got your order. Early ones had a bad reputation due to lots of jitter. They where pretty bad. It got worse that the reps where denying that there was a problem. Single-cycle jitter (which was relevant for that app) was clearly vissible and didn't take much effort to measure and toss the samples over the shoulder. But they where fairly simple PLL designs. One case I saw would allow the PLL to oscillate badly sometimes when you started it. For that app it was totally useless. These look good to me. (But I don't work in this area so maybe their marketing stuff fooled me.) This is time-nuts. What is good for one application will be useless for another. Spurs might be a problem, it depends on your application and the exact numbers of the target frequency and the crystal frequency. I could not agree more. These are good contribution to the design-scope for some applications. 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.
