Re: [time-nuts] gravity controlled pendulumn clock?
Gentlemen, gentlemen and gentlemen! We are time-nuts. Accuracy is paramount. We are scientists. Please steer clear of pounds, feet, cubic yards and other such rubbish. Scientists speak in metric and so should you. Please. Jim On 13 December 2011 16:24, Don Latham d...@montana.com wrote: or you can use a cubic yard of plain sand, about 2700# (depends on how moist it is) -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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] gravity controlled pendulumn clock?
Injection locking: perhaps the first to document this effect was indeed Christiaan Huygens.* * On Tue, Dec 13, 2011 at 10:28 AM, Jim Palfreyman jim77...@gmail.com wrote: Gentlemen, gentlemen and gentlemen! We are time-nuts. Accuracy is paramount. We are scientists. Please steer clear of pounds, feet, cubic yards and other such rubbish. Scientists speak in metric and so should you. Please. Jim On 13 December 2011 16:24, Don Latham d...@montana.com wrote: or you can use a cubic yard of plain sand, about 2700# (depends on how moist it is) -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. ___ 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] FE-5680A
On Mon, Dec 12, 2011 at 05:42:31PM -0800, Chris Albertson wrote: I was searching Google for information on these. Seems if you are not on this list info is hard to come by. I have bought one of these a couple of months ago. It's working, but I have not the opportunity to verify accuracy against anything better. In the first shipping run, the seller didn't include the oscillator you have on the mounting board, probably trying to sell them separately; only the DB9 connector was included. The part number on mine is 217400-30352-1. Best regards, Andrea Baldoni ___ 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] filtering a 10Mhz frequency standard?
Paul's simple filter: http://www.w1ghz.org/small_proj/small_proj.htm Mike - Original Message - From: Bob Bownes bow...@gmail.com To: li...@lazygranch.com; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, December 12, 2011 10:11 PM Subject: Re: [time-nuts] filtering a 10Mhz frequency standard? Paul Wade did a paper on 10Mhz GPSDO filtering for Microwave Update in October. It is in the proceedings. I don't know if it is available elsewhere. Bob On Mon, Dec 12, 2011 at 9:17 PM, li...@lazygranch.com wrote: I think you would want to avoid crystal filters due to microphonics. I've found building good LCR filters harder in real life than on paper. (I've done plenty of leapfrog active filters from LCR based designs.) I've had to make a passive LCR for ADC testing and secondary (parasitic elements of nonideal component) come into play. Nowadays I just buy COTS. --Original Message-- From: Chris Albertson Sender: time-nuts-boun...@febo.com To: Discussion of precise time and frequency measurement ReplyTo: Discussion of precise time and frequency measurement Subject: [time-nuts] filtering a 10Mhz frequency standard? Sent: Dec 12, 2011 5:54 PM What is the best practice for filtering a 10Mhz sine wave frequency standard? I've read that you can do more harm than good. Filter parts (caps, resistors and so on) are all temperature sensitive. But all those $40 Rb oscillators are putting out a pretty rough looking sine wave. Are some types of filters better. I thought about a crystal filters. -- 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 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] gravity controlled pendulumn clock?
Have we no female time-nuts? Interesting. On 12/13/2011 04:28 AM, Jim Palfreyman wrote: Gentlemen, gentlemen and gentlemen! ___ 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] FE-5680A
Just bought two for US99.98 (UK ~£66) with free shipping. Good deal. Will be interesting to see how they perform. Also interesting to know what FEI are currently quoting for new units. Last time I got a quote from them (5 years+) I was quoted over UK£1K each in single qty. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: 13 December 2011 02:17 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE-5680A If someone says or best offer of course I'm going to make a smaller offer when multiple items are for sale. This is what the seller is telling you to do. I bought one and finally tonight hooked it up to see if it ran. After a few minutes it locked up nice. For the price, I think I will pick up a couple more as I have lots of gear for which this would, even uncorrected, be an outstanding reference. I will make up small switching circuits (or even tiny relays, I need projects to use them up) to switch over from the crystal upon lock and light a LED on the front panels. Peter On 12/12/2011 8:42 PM, Chris Albertson wrote: On Mon, Dec 12, 2011 at 4:22 PM, Bob Campli...@rtty.us wrote: Hi My guess is that the supply is in the thousands... We don't know the number of units he has but was can see how many were sold. ebay provides a link to bidding and sales history. I looked and I say so far dozens not thousands. You can also see to first and last characters of the user names of each buyer and how many units each of them bought. Seems most people buy 1 unit but quite a few buy two at a time. I was searching Google for information on these. Seems if you are not on this list info is hard to come by. I'm buying one but I notice his price is or best offer. I'll let you all know what he accepts. I notice in thesales hstory he has accepted several offers and has several more pending. But eBay does not sell you what the offers were. No I'm not being cheap. I'm being curious. 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1415 / Virus Database: 2102/4077 - Release Date: 12/12/11 ___ 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] gravity controlled pendulumn clock?
Yawn! Jim Palfreyman wrote: Gentlemen, gentlemen and gentlemen! We are time-nuts. Accuracy is paramount. We are scientists. Please steer clear of pounds, feet, cubic yards and other such rubbish. Scientists speak in metric and so should you. Please. Jim ___ 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] filtering a 10Mhz frequency standard?
I just ordered the parts for this filter from Mouser Electronics. ~ $30 plus shipping including a shiny new Pomona box. qty 2 542-78F1R0-RC RF Inductors 1.0uH 10% @ $0.18 ea qty 2 140-50S5-271J-RC Ceramic Disc Capacitors 50V 270pF SL 5% Tol @ $0.14 ea qty 1 140-50S5-471J-RC Ceramic Disc Capacitors 50V 470pF SL 5% Tol @ $0.11 ea qty 1 565-3752 Test Connectors SHLD BOX BNC (M/F) @ $29.12 ea (ouch!) That's 75 cents in parts plus the box. Once assembled I'll sweep it with the network analyzer and report back on tweaks made to get it closer to the simulation. -Bob On Tue, Dec 13, 2011 at 4:08 AM, n1...@burlingtontelecom.net wrote: Paul's simple filter: http://www.w1ghz.org/small_**proj/small_proj.htmhttp://www.w1ghz.org/small_proj/small_proj.htm Mike - Original Message - From: Bob Bownes bow...@gmail.com To: li...@lazygranch.com; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, December 12, 2011 10:11 PM Subject: Re: [time-nuts] filtering a 10Mhz frequency standard? Paul Wade did a paper on 10Mhz GPSDO filtering for Microwave Update in October. It is in the proceedings. I don't know if it is available elsewhere. Bob On Mon, Dec 12, 2011 at 9:17 PM, li...@lazygranch.com wrote: I think you would want to avoid crystal filters due to microphonics. I've found building good LCR filters harder in real life than on paper. (I've done plenty of leapfrog active filters from LCR based designs.) I've had to make a passive LCR for ADC testing and secondary (parasitic elements of nonideal component) come into play. Nowadays I just buy COTS. --Original Message-- From: Chris Albertson Sender: time-nuts-boun...@febo.com To: Discussion of precise time and frequency measurement ReplyTo: Discussion of precise time and frequency measurement Subject: [time-nuts] filtering a 10Mhz frequency standard? Sent: Dec 12, 2011 5:54 PM What is the best practice for filtering a 10Mhz sine wave frequency standard? I've read that you can do more harm than good. Filter parts (caps, resistors and so on) are all temperature sensitive. But all those $40 Rb oscillators are putting out a pretty rough looking sine wave. Are some types of filters better. I thought about a crystal filters. -- 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-nutshttps://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-nutshttps://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-nutshttps://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-nutshttps://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] gravity controlled pendulumn clock?
...and just what is 'less accurate' about pounds, feet, cubic yards etc? The metric system (I use the term loosely) is ideal for those people who cannot do mental arithmetic and can only shift decimal points. All 'imperial' measurements can be defined just as the metre, kilogramme (and there is a dodgy one...)can be. Remember that the metre is originally based on (very) inaccurate French surveying techniques, a yard would do just as well. As a (somewhat middle-aged) physicist I'm perfectly happy with either system - although the imperial system is obviously better :-) . Just look what happened when NASA tried to use metric measurements for that Mars probe.. And does it really matter anyway? Paul Reeves, G8GJA -Original Message- From: Jim Palfreyman [mailto:jim77...@gmail.com] Sent: 13 December 2011 09:28 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] gravity controlled pendulumn clock? Gentlemen, gentlemen and gentlemen! We are time-nuts. Accuracy is paramount. We are scientists. Please steer clear of pounds, feet, cubic yards and other such rubbish. Scientists speak in metric and so should you. Please. Jim On 13 December 2011 16:24, Don Latham d...@montana.com wrote: or you can use a cubic yard of plain sand, about 2700# (depends on how moist it is) -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. This email, including any attachment, is a confidential communication intended solely for the use of the individual or entity to whom it is addressed. It contains information which is private and may be proprietary or covered by legal professional privilege. If you have received this email in error, please notify the sender upon receipt, and immediately delete it from your system. Anything contained in this email that is not connected with the businesses of this company is neither endorsed by nor is the liability of this company. Whilst we have taken reasonable precautions to ensure that any attachment to this email has been swept for viruses, we cannot accept liability for any damage sustained as a result of software viruses, and would advise that you carry out your own virus checks before opening any attachment. ___ 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] filtering a 10Mhz frequency standard?
Not to take anything away from Paul's design, but if you have to buy the box new, for three bucks more you can get a complete 10.7 MHz LPF with BNC connectors from MiniCircuits (Model BLP-10.7+, $32.95). They also have quite a few other useful cutoff frequencies -- 1.9 MHz, 5 MHz, 30 MHz, etc. John On 12/13/2011 9:08 AM, Robert Darlington wrote: I just ordered the parts for this filter from Mouser Electronics. ~ $30 plus shipping including a shiny new Pomona box. qty 2 542-78F1R0-RC RF Inductors 1.0uH 10% @ $0.18 ea qty 2 140-50S5-271J-RC Ceramic Disc Capacitors 50V 270pF SL 5% Tol @ $0.14 ea qty 1 140-50S5-471J-RC Ceramic Disc Capacitors 50V 470pF SL 5% Tol @ $0.11 ea qty 1 565-3752 Test Connectors SHLD BOX BNC (M/F) @ $29.12 ea (ouch!) That's 75 cents in parts plus the box. Once assembled I'll sweep it with the network analyzer and report back on tweaks made to get it closer to the simulation. -Bob ___ 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] gravity controlled pendulumn clock?
On 12/13/11 6:37 AM, Reeves Paul wrote: ...and just what is 'less accurate' about pounds, feet, cubic yards etc? The metric system (I use the term loosely) is ideal for those people who cannot do mental arithmetic and can only shift decimal points. All 'imperial' measurements can be defined just as the metre, kilogramme (and there is a dodgy one...)can be. Remember that the metre is originally based on (very) inaccurate French surveying techniques, a yard would do just as well. But it wouldn't be a nice 10,000 km from pole to equator... And besides that's the whole Britannia rules the waves so they get the prime meridian and the French make good maps so they get the meter thing. As a (somewhat middle-aged) physicist I'm perfectly happy with either system - although the imperial system is obviously better :-) . Just look what happened when NASA tried to use metric measurements for that Mars probe.. Actually, when a contractor used U.S. Customary units in data that was supposed to be delivered in Metric. NASA Deep Space Exploration has been metric for decades. I'd have to go look at some old documents to see if Mariner, Ranger, Voyager were inch/pound or metric. (Space Shuttle and part of ISS are U.S. Customary (aka inch/pound) for legacy manufacturing reasons..) And does it really matter anyway? ___ 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] filtering a 10Mhz frequency standard?
If your intent is to take full advantage of the long term as well as short term stability of a reference oscillator, the best approach is a low pass filter that will have small (and stable) phase shift at 10 MHz. Most bandpass filters will have enough temperature sensitivity of the phase shift through the filter to degrade the performance of an Rb. It may look fine on the scope but would not give you good long term adev. If you don't care about long term stability, you probably do not need an Rb in the first place. If you only need good long term frequency stability and phase (or absolute time) is of no concern, then the type of filter (and whether there is a filter or not) does not matter. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Chris Albertson albertson.ch...@gmail.com Sender: time-nuts-boun...@febo.com Date: Mon, 12 Dec 2011 17:54:09 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] filtering a 10Mhz frequency standard? What is the best practice for filtering a 10Mhz sine wave frequency standard? I've read that you can do more harm than good. Filter parts (caps, resistors and so on) are all temperature sensitive. But all those $40 Rb oscillators are putting out a pretty rough looking sine wave. Are some types of filters better. I thought about a crystal filters. -- 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] gravity controlled pendulumn clock?
I thought we were all bi-lingual on this site :-) Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Jim Palfreyman Sent: 13 December 2011 09:28 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] gravity controlled pendulumn clock? Gentlemen, gentlemen and gentlemen! We are time-nuts. Accuracy is paramount. We are scientists. Please steer clear of pounds, feet, cubic yards and other such rubbish. Scientists speak in metric and so should you. Please. Jim On 13 December 2011 16:24, Don Latham d...@montana.com wrote: or you can use a cubic yard of plain sand, about 2700# (depends on how moist it is) -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. ___ 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] gravity controlled pendulumn clock?
But it wouldn't be a nice 10,000 km from pole to equator... And surprise! It still isn't! It is more like 12,713.5 km. ... unless you measure it to one significant figure. Metric vs English is purely about a set of arbitrary constants. Decimal pounds, decimal inches and decimal seconds is just as arbitrary, and just as easy to use as the metric system. And besides that's the whole Britannia rules the waves so they get the prime meridian and the French make good maps so they get the meter thing. I think it was more that the French were so ghoulishly violent with their revolution that the rest of Europe was afraid of them. -Chuck Harris ___ 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] gravity controlled pendulumn clock?
Ah yes, God's units as revealed by the French. :-)my mistake Don Jim Palfreyman Gentlemen, gentlemen and gentlemen! We are time-nuts. Accuracy is paramount. We are scientists. Please steer clear of pounds, feet, cubic yards and other such rubbish. Scientists speak in metric and so should you. Please. Jim On 13 December 2011 16:24, Don Latham d...@montana.com wrote: or you can use a cubic yard of plain sand, about 2700# (depends on how moist it is) -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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] gravity controlled pendulumn clock?
What's metric or Common Measure about seconds? ;) Bob On Tue, Dec 13, 2011 at 11:47 AM, Don Latham d...@montana.com wrote: Ah yes, God's units as revealed by the French. :-)my mistake Don Jim Palfreyman Gentlemen, gentlemen and gentlemen! We are time-nuts. Accuracy is paramount. We are scientists. Please steer clear of pounds, feet, cubic yards and other such rubbish. Scientists speak in metric and so should you. Please. Jim On 13 December 2011 16:24, Don Latham d...@montana.com wrote: or you can use a cubic yard of plain sand, about 2700# (depends on how moist it is) -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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] filtering a 10Mhz frequency standard?
see also: www.timeok.it/files/10_mhz_bandpass_filter.pdf Luciano Luciano P. S. Paramithiotti IZ5JHJ - Original Message From: n1...@burlingtontelecom.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] filtering a 10Mhz frequency standard? Date: Dec 13, 2011 12:12 PM Paul's simple filter: http://www.w1ghz.org/small_proj/small_proj.htm Mike - Original Message - From: quot;Bob Bownesquot; lt;bow...@gmail.comgt; To: lt;li...@lazygranch.comgt;; quot;Discussion of precise time and frequency measurementquot; lt;time-nuts@febo.comgt; Sent: Monday, December 12, 2011 10:11 PM Subject: Re: [time-nuts] filtering a 10Mhz frequency standard? Paul Wade did a paper on 10Mhz GPSDO filtering for Microwave Update in October. It is in the proceedings. I don't know if it is available elsewhere. Bob On Mon, Dec 12, 2011 at 9:17 PM, lt;li...@lazygranch.comgt; wrote: gt; I think you would want to avoid crystal filters due to microphonics. gt; gt; I've found building good LCR filters harder in real life than on paper. gt; (I've done plenty of leapfrog active filters from LCR based designs.) I've gt; had to make a passive LCR for ADC testing and secondary (parasitic gt; elements of nonideal component) come into play. Nowadays I just buy COTS. gt; gt; gt; --Original Message-- gt; From: Chris Albertson gt; Sender: time-nuts-boun...@febo.com gt; To: Discussion of precise time and frequency measurement gt; ReplyTo: Discussion of precise time and frequency measurement gt; Subject: [time-nuts] filtering a 10Mhz frequency standard? gt; Sent: Dec 12, 2011 5:54 PM gt; gt; What is the best practice for filtering a 10Mhz sine wave frequency gt; standard? I've read that you can do more harm than good. Filter gt; parts (caps, resistors and so on) are all temperature sensitive. But gt; all those $40 Rb oscillators are putting out a pretty rough looking gt; sine wave. gt; gt; Are some types of filters better. I thought about a crystal filters. gt; gt; -- gt; gt; Chris Albertson gt; Redondo Beach, California gt; gt; ___ gt; time-nuts mailing list -- time-nuts@febo.com gt; To unsubscribe, go to gt; https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts gt; and follow the instructions there. gt; ___ gt; time-nuts mailing list -- time-nuts@febo.com gt; To unsubscribe, go to gt; https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts gt; 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. Sent to you using Uebimiau Webmail version 3.11 Developed by Dave and Todd at http://www.manvel.net and http://www.tdah.us ___ 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] gravity controlled pendulumn clock?
I'm a scientist? :-) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Bownes Sent: 13 December 2011 16:57 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] gravity controlled pendulumn clock? What's metric or Common Measure about seconds? ;) Bob On Tue, Dec 13, 2011 at 11:47 AM, Don Latham d...@montana.com wrote: Ah yes, God's units as revealed by the French. :-)my mistake Don Jim Palfreyman Gentlemen, gentlemen and gentlemen! We are time-nuts. Accuracy is paramount. We are scientists. Please steer clear of pounds, feet, cubic yards and other such rubbish. Scientists speak in metric and so should you. Please. Jim On 13 December 2011 16:24, Don Latham d...@montana.com wrote: or you can use a cubic yard of plain sand, about 2700# (depends on how moist it is) -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. ___ 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] filtering a 10Mhz frequency standard?
I reported a filter design I was working on back in November, using 10 base T LAN filter modules. The first experimental air-wired unit with two modules got to about -75 dBc at 30 MHz, rising to -65 dBc at 70 MHz. After building the same circuit with shielded compartments, it ran about -85 dBc flat over this range, but it should have been over 100. The weak link turned out to be the cross-talk within the modules themselves - there are two 17 MHz LPF sections in each, and I cascaded them all. Four separate modules cascaded, using only the Tx portion of each, should reach about 120 dBc rejection, with about 6 dB insertion loss. The original two-module circuit (or maybe even a single one) would probably suffice for most applications. I haven't yet impedance matched the 100 ohm differential filters to the 50 ohm cable environment - I'm thinking it may not even be necessary. If you have any old LAN cards, hubs, or routers around, you may already have some nice free LPFs for this purpose. The box to put them in (packaging cost) is another matter. 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.
[time-nuts] Fwd: Re: Using a Racal 1992
Here is a plot from the latest GPIB hack which reads frequency and phase
about once per second. Only the phase is shown here. Small tweeks to the
fine freq standard adjustment take several minutes to take effect. Is
the fine adjustment tweeking some parameter related to the oven??? On
12/11/2011 07:34 AM, Larry McDavid wrote: Chuck, what is the time
scale in your plot? That is, why does 1400 = 430 seconds? Larry
On 12/10/2011 10:35 PM, Chuck Forsberg WA7KGX N2469R wrote:
The 1992's A input goes to the Thunderbolt. The 1992's B input goes
to its time base output. The counter is set to A rel B Here's
a blow-up of the phase plot. In this case it takes some 430 seconds
for the phase offset to cycle 360 degrees. In other words, there is
1/430 Hz frequency difference. ... -- Chuck Forsberg WA7KGX
N2469R c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for
Embedded Applications Omen Technology Inc The High Reliability
Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430
attachment: phase3.gif
/***
rdxp.c
Read phase and freq from Racal-Dana 1992
---
***/
#include ctype.h
#include errno.h
#include stdio.h
#include unistd.h
#include stdlib.h
#include stdint.h
#include string.h
#include getopt.h
#include sys/time.h
#include gpib/ib.h
#define LL 132
char line[LL];
long double phase, freq;
struct timeval tv;
long long tt;
FILE *fout;
int ud, minor=0, pad = 15;
const int sad = 0;
const int send_eoi = 1;
const int eos_mode = 0;
const int timeout = T1s;
int once = 1; // discard garbage readings forst time around
main(argc, argv)
{
long long l;
fout = fopen(/o/tmp/rdxp, w);
if (fout == NULL)
fprintf(stderr, Can't open output file.\n);
fprintf(stderr, trying to open pad = %i on /dev/gpib%i ... , pad,
minor);
ud = ibdev(minor, pad, sad, timeout, send_eoi, eos_mode);
if(ud 0)
{
fprintf(stderr, ibdev error\n);
return (-1);
}
fprintf(stderr, ud = %d\n, ud);
ibrsc(ud, 1);
ibsic(ud);
ibclr(ud);
ibsre(ud, 1);
ibwrt(ud, SRS9\n, 5); // set high res
once = 1;
while (1) {
ibwrt(ud, PH\n, 3); // measure phase
line[0] = 0;
Receive (0, 15, line, LL, 012);
if (strncmp(line, PH, 2)) {
fprintf(stderr, PH Timeout\n); continue;
}
// fputs (line, stdout);
sscanf (line+2, %Le, phase);
ibwrt(ud, FA\n, 3); // Measure freq input A
line[0] = 0;
Receive (0, 15, line, LL, 012);
if (strncmp(line, FA, 2)) {
fprintf(stderr, FA Timeout\n); continue;
}
// fputs (line, stdout);
gettimeofday(tv, NULL); tt = tv.tv_sec;
sscanf (line+2, %Le, freq);
/*
* Display freq as deviation from the nearest MHz
*/
l = freq + 5.;
l /= 10;
l *= 10;
freq -= l;
if (once) {once = 0; continue;}
fprintf(stdout, %lld %12.2Lf %3.0Lf\n, tt, freq, phase );
fflush(stdout);
if (fout != NULL) {
fprintf(fout,%lld %12.2Lf %3.0Lf\n, tt, freq, phase );
fflush(fout);
}
}
}
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Re: [time-nuts] Pear shaped earth
Hi I'd second that recommendation. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of lstosk...@cox.net Sent: Monday, December 12, 2011 10:18 PM To: time-nuts@febo.com Cc: time-nuts-requ...@febo.com Subject: Re: [time-nuts] Pear shaped earth Interestingly, until there were artificial satellites, you couldn't tell that the earth is slightly pear shaped. You need to read Measure of the Earth N0UU ___ 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] gravity controlled pendulumn clock?
On 12/13/11 8:19 AM, Chuck Harris wrote: But it wouldn't be a nice 10,000 km from pole to equator... And surprise! It still isn't! It is more like 12,713.5 km. Huh? For WGS84 ellipsoid Equatorial radius 6378km * 2 * pi = 40080.4 km Polar Radius 6357km (Clarke 1866 is 6377.5, 6356.6) At about 49 degrees latitude (e.g. Paris), the radius of curvature is about 6366km which corresponds to .68 km from pole to equator. A more precise calculation gives a meridional radius of 6367.4491 km for a circumference 40007.86 km.. Delambre estimated 6377 for equatorial in 1810. ... unless you measure it to one significant figure. Metric vs English is purely about a set of arbitrary constants. Decimal pounds, decimal inches and decimal seconds is just as arbitrary, and just as easy to use as the metric system. And besides that's the whole Britannia rules the waves so they get the prime meridian and the French make good maps so they get the meter thing. I think it was more that the French were so ghoulishly violent with their revolution that the rest of Europe was afraid of them. Yes, that might have had an effect... -Chuck Harris ___ 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] filtering a 10Mhz frequency standard?
Hi Regardless of the design, what ever filter you use will be sensitive to load. Hooking up a few dozen instruments to a standard line with BNC T's is unlikely to present 50 ohms to the filter. The more complex the filter, generally the more sensitive it will be Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ed breya Sent: Tuesday, December 13, 2011 12:07 PM To: time-nuts@febo.com Subject: [time-nuts] filtering a 10Mhz frequency standard? I reported a filter design I was working on back in November, using 10 base T LAN filter modules. The first experimental air-wired unit with two modules got to about -75 dBc at 30 MHz, rising to -65 dBc at 70 MHz. After building the same circuit with shielded compartments, it ran about -85 dBc flat over this range, but it should have been over 100. The weak link turned out to be the cross-talk within the modules themselves - there are two 17 MHz LPF sections in each, and I cascaded them all. Four separate modules cascaded, using only the Tx portion of each, should reach about 120 dBc rejection, with about 6 dB insertion loss. The original two-module circuit (or maybe even a single one) would probably suffice for most applications. I haven't yet impedance matched the 100 ohm differential filters to the 50 ohm cable environment - I'm thinking it may not even be necessary. If you have any old LAN cards, hubs, or routers around, you may already have some nice free LPFs for this purpose. The box to put them in (packaging cost) is another matter. 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. ___ 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] gravity controlled pendulumn clock?
On 12/13/11 8:57 AM, Bob Bownes wrote: What's metric or Common Measure about seconds? ;) Bob AN excellent point.. aren't seconds the only unit that is the same in basically all measurement systems? there's cgs, mks, SI, Imperial, US Customary, Avoirdupois, etc and they all use seconds. And since this is timenuts.. where did the second originate (I recall a story about Galileo counting heartbeats for his experiments rolling balls down ramps... but that sounds a bit too convenient). Is it just dividing hours by 60 to get minutes and minutes by 60 to get seconds (as my daughter was wont to say when learning fractions: curse those Babylonians) http://tf.boulder.nist.gov/general/pdf/2209.pdf makes it seem to be Claudius Ptolemy ___ 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] filtering a 10Mhz frequency standard?
Yes, you don't want to send un-buffered (or unprotected) signals - especially right out of a filter - out for distribution. I have found that some pieces of equipment will only take the external reference over a certain small level range, so the distribution amplifier needs to have an assortment of levels, or some that are adjustable. Each instrument should have its own line from the amplifier unit, set to the right level, or for remote sending, a power splitter port from a common line. Ed on Tue Dec 13 17:19:12 UTC 2011 Bob Camp wrote: Regardless of the design, what ever filter you use will be sensitive to load. Hooking up a few dozen instruments to a standard line with BNC T's is unlikely to present 50 ohms to the filter. The more complex the filter, generally the more sensitive it will be ___ 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] gravity controlled pendulumn clock?
Yes, but different seconds. I learned many years ago to use the RSF (rod-stone-fortnight) system of units. Small errors are much smaller... Don Jim Lux On 12/13/11 8:57 AM, Bob Bownes wrote: What's metric or Common Measure about seconds? ;) Bob AN excellent point.. aren't seconds the only unit that is the same in basically all measurement systems? there's cgs, mks, SI, Imperial, US Customary, Avoirdupois, etc and they all use seconds. And since this is timenuts.. where did the second originate (I recall a story about Galileo counting heartbeats for his experiments rolling balls down ramps... but that sounds a bit too convenient). Is it just dividing hours by 60 to get minutes and minutes by 60 to get seconds (as my daughter was wont to say when learning fractions: curse those Babylonians) http://tf.boulder.nist.gov/general/pdf/2209.pdf makes it seem to be Claudius Ptolemy ___ 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. R. Bacon 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] gravity controlled pendulumn clock?
I saw: pole to equator and read: pole to pole, or diameter. A simple literacy problem... -Chuck Harris Jim Lux wrote: On 12/13/11 8:19 AM, Chuck Harris wrote: But it wouldn't be a nice 10,000 km from pole to equator... And surprise! It still isn't! It is more like 12,713.5 km. Huh? For WGS84 ellipsoid Equatorial radius 6378km * 2 * pi = 40080.4 km Polar Radius 6357km ... ___ 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] gravity controlled pendulumn clock?
Number one rule in life - never lose your sense of humour! Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Don Latham Sent: 13 December 2011 18:38 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] gravity controlled pendulumn clock? Yes, but different seconds. I learned many years ago to use the RSF (rod-stone-fortnight) system of units. Small errors are much smaller... Don Jim Lux On 12/13/11 8:57 AM, Bob Bownes wrote: What's metric or Common Measure about seconds? ;) Bob AN excellent point.. aren't seconds the only unit that is the same in basically all measurement systems? there's cgs, mks, SI, Imperial, US Customary, Avoirdupois, etc and they all use seconds. And since this is timenuts.. where did the second originate (I recall a story about Galileo counting heartbeats for his experiments rolling balls down ramps... but that sounds a bit too convenient). Is it just dividing hours by 60 to get minutes and minutes by 60 to get seconds (as my daughter was wont to say when learning fractions: curse those Babylonians) http://tf.boulder.nist.gov/general/pdf/2209.pdf makes it seem to be Claudius Ptolemy ___ 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. R. Bacon 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] gravity controlled pendulumn clock?
On Tue, Dec 13, 2011 at 08:19, Chuck Harris cfhar...@erols.com wrote: Metric vs English is purely about a set of arbitrary constants. Decimal pounds, decimal inches and decimal seconds is just as arbitrary, and just as easy to use as the metric system. I would agree, as long as you stay within a single version of the English system. But where the metric system has an advantage is that the units with the same name are the same size everywhere; that's not true of English units. I can remember mixing Kodak photographic chemicals for darkroom use, where the mixing instructions are in terms of ounces and gallons. But I was in Canada, where the Imperial (British) ounce and gallon are both different volumes than the American (and thus Kodak) units of the same name. I didn't *have* measuring cups with US ounce markings. We solved the problem by converting the foreign units to ml and litres, which we were equipped to measure. If I remember correctly, Ilford's photo chemical mixing directions were already in metric, so they applied worldwide without any units confusion. Fortunately, the inch seems to be the same size everywhere, so I don't have to figure out whether someone is talking about British inches or American inches. I have a small lathe with inch leadscrews, and a small milling machine with metric leadscrews. Neither measurement system is particularly better or worse than the other. Many of my measuring tools can display in either system. Imagine the chaos if the second was a different length of time in different countries. - 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] gravity controlled pendulumn clock?
Having spent more of my adult life in the US than in France, and having been thoroughly exposed to both systems, I can testify (in my own name) that it is easier and faster to get a good approximation when doing mental arithmetic on engineering problems using the metric system than the imperial system. Of course, when you punch numbers in a calculator, the difference is less (even though there are fewer constants involved when using the metric system in general) so there is less typing involved. If you don't care about being accurate, then the imperial system is fine :) A gallon ( a yard, a pound,...) are not the same depending on where you are, and I am not talking about relativistic effects (or maybe I am...). Who cares how much is an ounce of water anyhow? Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Reeves Paul paul.ree...@uk.thalesgroup.com Sender: time-nuts-boun...@febo.com Date: Tue, 13 Dec 2011 14:37:44 To: 'Discussion of precise time and frequency measurement'time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] gravity controlled pendulumn clock? ...and just what is 'less accurate' about pounds, feet, cubic yards etc? The metric system (I use the term loosely) is ideal for those people who cannot do mental arithmetic and can only shift decimal points. All 'imperial' measurements can be defined just as the metre, kilogramme (and there is a dodgy one...)can be. Remember that the metre is originally based on (very) inaccurate French surveying techniques, a yard would do just as well. As a (somewhat middle-aged) physicist I'm perfectly happy with either system - although the imperial system is obviously better :-) . Just look what happened when NASA tried to use metric measurements for that Mars probe.. And does it really matter anyway? Paul Reeves, G8GJA -Original Message- From: Jim Palfreyman [mailto:jim77...@gmail.com] Sent: 13 December 2011 09:28 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] gravity controlled pendulumn clock? Gentlemen, gentlemen and gentlemen! We are time-nuts. Accuracy is paramount. We are scientists. Please steer clear of pounds, feet, cubic yards and other such rubbish. Scientists speak in metric and so should you. Please. Jim On 13 December 2011 16:24, Don Latham d...@montana.com wrote: or you can use a cubic yard of plain sand, about 2700# (depends on how moist it is) -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon 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. This email, including any attachment, is a confidential communication intended solely for the use of the individual or entity to whom it is addressed. It contains information which is private and may be proprietary or covered by legal professional privilege. If you have received this email in error, please notify the sender upon receipt, and immediately delete it from your system. Anything contained in this email that is not connected with the businesses of this company is neither endorsed by nor is the liability of this company. Whilst we have taken reasonable precautions to ensure that any attachment to this email has been swept for viruses, we cannot accept liability for any damage sustained as a result of software viruses, and would advise that you carry out your own virus checks before opening any attachment. ___ 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] Pear shaped earth
Really it is more like potato shaped :) El 13/12/2011 18:12, Bob Camp escribió: Hi I'd second that recommendation. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of lstosk...@cox.net Sent: Monday, December 12, 2011 10:18 PM To: time-nuts@febo.com Cc: time-nuts-requ...@febo.com Subject: Re: [time-nuts] Pear shaped earth Interestingly, until there were artificial satellites, you couldn't tell that the earth is slightly pear shaped. You need to read Measure of the Earth N0UU ___ 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] filtering a 10Mhz frequency standard?
If you are going to buffer the output, why does the filter have to be passive? Did I miss something here? Today 10MHz is in the realm of active filters. [Hey, not that I made an active filter at 10MHz.] Sensitivity is a function of the denominator. The only advantage to a LPF over a BPF is the BPF has to be centered at 10MHz, while you could bump the corner of the LPF to a higher frequency so there is less sensitivity at 10MHz This presumes you are only getting rid of harmonics and not spurs. For lowest component sensitivity, leap frog designs are best. But in continuous time designs, they require many op amps per pole. ___ 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] filtering a 10Mhz frequency standard?
If your concern is harmonics, the best combination is a low pass filter that cuts high enough to have no (or negligible) group delay at 10 MHz, and one or more notch filters for the harmonics, as many as necessary to get the attenuation you desire. These filters should have no measurable effect on the fundamental. If you have phase noise or spurs near the carrier, you need a cleanup PLL with a good crystal and a narrow BW. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: gary li...@lazygranch.com Sender: time-nuts-boun...@febo.com Date: Tue, 13 Dec 2011 13:27:54 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] filtering a 10Mhz frequency standard? If you are going to buffer the output, why does the filter have to be passive? Did I miss something here? Today 10MHz is in the realm of active filters. [Hey, not that I made an active filter at 10MHz.] Sensitivity is a function of the denominator. The only advantage to a LPF over a BPF is the BPF has to be centered at 10MHz, while you could bump the corner of the LPF to a higher frequency so there is less sensitivity at 10MHz This presumes you are only getting rid of harmonics and not spurs. For lowest component sensitivity, leap frog designs are best. But in continuous time designs, they require many op amps per pole. ___ 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] gravity controlled pendulumn clock?
I find the biggest problem in units is when you want to solve a physics problem and need data on typical physical properties of substances, for instance design of thermal insulation for an OCXO. You can look through dozens of books with tables of typical values, most of which are in units of BTU/square foot/inch/hour, and a bewildering mixture of other units, and are usually wrong! Decimal points are slipped, or the values are reciprocals, or the numbers have been lifted from a different industry book that uses different units. It is quite messy to have to measure these things from first principles. At least with metric you can keep looking until you find 5 books that agree, you can see the value with the slipped decimal, and then you may have values that may be reliable or at least stolen from the same source. And you get your answer in Watts. cheers, Neville Michie ___ 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] Ebay FE-5680A Rb I see the price has gone up for these
I guess they figured out they had some value. Such is life. Regards Paul WB8TSL/1 ___ 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] Fwd: Re: Using a Racal 1992
Chuck wrote: Small tweeks to the fine freq ... adjustment take several minutes to take effect. Is the fine adjustment tweeking some parameter related to the oven??? I doubt it, but I do not have actual knowledge of the inner workings. I have found that the heat loss (I assume) through the open adjustment plug screw causes an error -- you can get them adjusted as closely as you can (in my experience, about 1E-9 with lots of hair-pulling) and they will sit there stably for as long as you want, then when you put the plug screw back in they drift several parts in e-9 or more over a period of 10-15 minutes and stabilize at a new value. The good news is that the Racal oscillators in my 1992s are very stable long-term performers -- and significantly less position-sensitive than many others. So, you don't have to adjust them very often. The bad news is that getting them really, really close to the desired frequency is like herding cats. Other than the flaky pushbuttons on some of them, I have found that 1992s are extremely dependable. When a 9-digit counter will do, they are a great choice. (Of course, as time/frequency nuts we quickly outgrow 9-digit counters. Doesn't every measurement require 12 digits referenced to an H-maser?) I think it's been asked, and recently, but I haven't seen a positive response. Does anybody have schematics for the Racal OCXOs they can make available? 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] Ebay FE-5680A Rb I see the price has gone up for these
Make an offer and see what happens. On 12/13/11, paul swedpaulsw...@gmail.com wrote: I guess they figured out they had some value. Such is life. Regards Paul WB8TSL/1 ___ time-nuts mailing list -- [1]time-nuts@febo.com To unsubscribe, go to [2]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. References 1. mailto:time-nuts@febo.com 2. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ 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] Fwd: Re: Using a Racal 1992
On 12/13/2011 2:44 PM, Charles P. Steinmetz wrote: I think it's been asked, and recently, but I haven't seen a positive response. Does anybody have schematics for the Racal OCXOs they can make available? Charles, I have a hand drawn circuit diagram of the 9442 rapid warm up oven which I made, no guarantee as to accuracy, a copy of which you are welcome to. There is a person advertising others on the net, but he never has bothered to answer my repeated emails, see: http://www.antronic-data-systems.co.uk/page76.html In any case he charges more than I have paid for the ovens themselves on eBay. The one in the US mil version of the 1992 was only used in that from my experience. Yes, it is a good oven, and tricky to adjust. If you want better accuracy, that's why there is an external input :^) Dan ___ 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] gravity controlled pendulumn clock?
On 12/13/11 12:26 PM, shali...@gmail.com wrote: Having spent more of my adult life in the US than in France, and having been thoroughly exposed to both systems, I can testify (in my own name) that it is easier and faster to get a good approximation when doing mental arithmetic on engineering problems using the metric system than the imperial system. Of course, when you punch numbers in a calculator, the difference is less (even though there are fewer constants involved when using the metric system in general) so there is less typing involved. If you don't care about being accurate, then the imperial system is fine :) A gallon ( a yard, a pound,...) are not the same depending on where you are, and I am not talking about relativistic effects (or maybe I am...). Who cares how much is an ounce of water anyhow? Oh, then you're getting into all sorts of interesting units. Gallons, corn gallons, Scots gallons, etc. And when speaking of drink, for some amount of time in England, if you bought it in a bar, it could only be served and priced in fractions of a gill (for distilled spirits) or no less than a pint (for cider, beer, etc.) (a pint is, of course, 4 gill (except in Scotland), and since a gill is 5 fluid ounces, that makes the pint of beer some 20 ounces). And we are not speaking here of archaic units that haven't been seen in centuries. I think the UK went away from the gill fraction thing in bars (I don't recall seeing the sign about all spirits sold in this establishment... last winter in Heathrow), but it certainly existed in the early to mid 90s. (There's this weird alcohol unit thing, but I have no idea what that is.. probably some quasi metric measure of equivalent ethanol). I think, also, that in Australia, the pint of beer varies among states. And the stone is still used as a measure of human weight (and for perhaps other purposes) My wife's English relatives talk about gaining a stone over the holidays. And when hiring a horse to ride in the southwest of England, they tend to ask what you weigh in stone (but the horse business is the epitome of archaic.. Even in the more modern US we run races in furlongs, timing them in 1/5ths of a second, measure height of the horse in hands, although we do weigh jockeys in pounds) There are also a whole host of fair weight and measure laws in most countries which regulate the minimum sale quantity of something (e.g. you cannot buy a loaf of bread weighing less than a pound in the state of Oregon, raising an issue if you wish to purchase a demi-baguette). Likewise, vegetables and fruit have minimum sale quantities (the odd dry pint). I think in Germany, there's a minimum sale quantity for beverages, as well. ___ 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] Fwd: Re: Using a Racal 1992
Didier's site has a manual for the 1995-1996 which shows the OCXO's doubler circuit, if that helps. I think it's the same as in the 1992. http://www.ko4bb.com/Manuals/Racal/RACAL19951996OperationandService.pdf Aart Olsen - Original Message - I think it's been asked, and recently, but I haven't seen a positive response. Does anybody have schematics for the Racal OCXOs they can make available? ___ 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] Software for Tektronix FCA3100 Counter -- AKA Pendulum CNT91
Earlier this year I got a very good deal on an as new Tektronix FCA3100 Timer/Counter/Analyzer, which turned out to be a rebadged Pendulum CNT91. Pendulum offers what looks to be some very nice software for this unit, what it calls its TimeView Modulation Domain Analyzer, but Tektronix have quoted me a price for that in excess of what I paid for the counter itself. Does anybody know of any similar software that can be used with these counters, ideally free:-), but at the very least a lot cheaper than the 600 or 700 GBP I was quoted by Tektronix? Regards Nigel GM8PZR ___ 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] gravity controlled pendulumn clock?
I don't understand at all the arguments against the metric system and the polemic remarks about. I second the statements of Neville and Jim. Without these intelligent french Astronomers like Jean-Baptiste-Joseph Delambre, Pierre-François-André Méchain and J.J. Lalande (more infos: Ken Alder, The Measure of All Things), we would still have the severe problems they had centuries ago! Reading WIKIPEDIA, http://en.wikipedia.org /wiki/German_units_of_measurement, we find a good example of weird units (just for only a part of Germany): Before the introduction of the metric system in Germany, almost every town had its own definitions of the units shown below, and supposedly by 1810, in Baden alone, there were 112 different standards for the Elle around Germany. The metric system was a much-needed standardisation in Germany. This was not only a german problem, and we still have today some problems in the world in this area. I believe we should think more about what we are saying and doing, so we would do a big step forward to become a world community. ... Sorry for this personal opinion and comments, let us come back to timing problems with scientific and technical discussions, regards, Arnold Am 14.12.2011 00:15, schrieb Jim Lux: On 12/13/11 12:26 PM, shali...@gmail.com wrote: Having spent more of my adult life in the US than in France, and having been thoroughly exposed to both systems, I can testify (in my own name) that it is easier and faster to get a good approximation when doing mental arithmetic on engineering problems using the metric system than the imperial system. Of course, when you punch numbers in a calculator, the difference is less (even though there are fewer constants involved when using the metric system in general) so there is less typing involved. If you don't care about being accurate, then the imperial system is fine :) A gallon ( a yard, a pound,...) are not the same depending on where you are, and I am not talking about relativistic effects (or maybe I am...). Who cares how much is an ounce of water anyhow? Oh, then you're getting into all sorts of interesting units. Gallons, corn gallons, Scots gallons, etc. And when speaking of drink, for some amount of time in England, if you bought it in a bar, it could only be served and priced in fractions of a gill (for distilled spirits) or no less than a pint (for cider, beer, etc.) (a pint is, of course, 4 gill (except in Scotland), and since a gill is 5 fluid ounces, that makes the pint of beer some 20 ounces). And we are not speaking here of archaic units that haven't been seen in centuries. I think the UK went away from the gill fraction thing in bars (I don't recall seeing the sign about all spirits sold in this establishment... last winter in Heathrow), but it certainly existed in the early to mid 90s. (There's this weird alcohol unit thing, but I have no idea what that is.. probably some quasi metric measure of equivalent ethanol). I think, also, that in Australia, the pint of beer varies among states. And the stone is still used as a measure of human weight (and for perhaps other purposes) My wife's English relatives talk about gaining a stone over the holidays. And when hiring a horse to ride in the southwest of England, they tend to ask what you weigh in stone (but the horse business is the epitome of archaic.. Even in the more modern US we run races in furlongs, timing them in 1/5ths of a second, measure height of the horse in hands, although we do weigh jockeys in pounds) There are also a whole host of fair weight and measure laws in most countries which regulate the minimum sale quantity of something (e.g. you cannot buy a loaf of bread weighing less than a pound in the state of Oregon, raising an issue if you wish to purchase a demi-baguette). Likewise, vegetables and fruit have minimum sale quantities (the odd dry pint). I think in Germany, there's a minimum sale quantity for beverages, as well. ___ 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] Ebay FE-5680A Rb I see the price has gone up for these
Anyone who is interested in buying these units should take a look at the completed listings and be guided accordingly when making an offer. I recently picked up a couple for ~ $35 each, including shipping. True the price may be going up, but it looks like you can still get them for under $40 with shipping if you don't mind waiting for the slow boat from China. For experimentation, that is still a good deal. (I must admit that I didn't need them, but want to try pairing them with a couple Thunderbolts.) ___ 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] gravity controlled pendulumn clock?
The beautiful irony in all of this, is that the negative statements about metric and the desire not to change to the metric system comes from the US, yet it was Benjamin Franklin and Thomas Jefferson who took the original idea to France when they were ambassadors. The French ran with it and the US didn't (missing out by only a few votes). Oh well. Jim On 14 December 2011 12:01, Arnold Tibus arnold.ti...@gmx.de wrote: I don't understand at all the arguments against the metric system and the polemic remarks about. I second the statements of Neville and Jim. Without these intelligent french Astronomers like Jean-Baptiste-Joseph Delambre, Pierre-François-André Méchain and J.J. Lalande (more infos: Ken Alder, The Measure of All Things), we would still have the severe problems they had centuries ago! Reading WIKIPEDIA, http://en.wikipedia.org /wiki/German_units_of_measurement, we find a good example of weird units (just for only a part of Germany): Before the introduction of the metric system in Germany, almost every town had its own definitions of the units shown below, and supposedly by 1810, in Baden alone, there were 112 different standards for the Elle around Germany. The metric system was a much-needed standardisation in Germany. This was not only a german problem, and we still have today some problems in the world in this area. I believe we should think more about what we are saying and doing, so we would do a big step forward to become a world community. ... Sorry for this personal opinion and comments, let us come back to timing problems with scientific and technical discussions, regards, Arnold Am 14.12.2011 00:15, schrieb Jim Lux: On 12/13/11 12:26 PM, shali...@gmail.com wrote: Having spent more of my adult life in the US than in France, and having been thoroughly exposed to both systems, I can testify (in my own name) that it is easier and faster to get a good approximation when doing mental arithmetic on engineering problems using the metric system than the imperial system. Of course, when you punch numbers in a calculator, the difference is less (even though there are fewer constants involved when using the metric system in general) so there is less typing involved. If you don't care about being accurate, then the imperial system is fine :) A gallon ( a yard, a pound,...) are not the same depending on where you are, and I am not talking about relativistic effects (or maybe I am...). Who cares how much is an ounce of water anyhow? Oh, then you're getting into all sorts of interesting units. Gallons, corn gallons, Scots gallons, etc. And when speaking of drink, for some amount of time in England, if you bought it in a bar, it could only be served and priced in fractions of a gill (for distilled spirits) or no less than a pint (for cider, beer, etc.) (a pint is, of course, 4 gill (except in Scotland), and since a gill is 5 fluid ounces, that makes the pint of beer some 20 ounces). And we are not speaking here of archaic units that haven't been seen in centuries. I think the UK went away from the gill fraction thing in bars (I don't recall seeing the sign about all spirits sold in this establishment... last winter in Heathrow), but it certainly existed in the early to mid 90s. (There's this weird alcohol unit thing, but I have no idea what that is.. probably some quasi metric measure of equivalent ethanol). I think, also, that in Australia, the pint of beer varies among states. And the stone is still used as a measure of human weight (and for perhaps other purposes) My wife's English relatives talk about gaining a stone over the holidays. And when hiring a horse to ride in the southwest of England, they tend to ask what you weigh in stone (but the horse business is the epitome of archaic.. Even in the more modern US we run races in furlongs, timing them in 1/5ths of a second, measure height of the horse in hands, although we do weigh jockeys in pounds) There are also a whole host of fair weight and measure laws in most countries which regulate the minimum sale quantity of something (e.g. you cannot buy a loaf of bread weighing less than a pound in the state of Oregon, raising an issue if you wish to purchase a demi-baguette). Likewise, vegetables and fruit have minimum sale quantities (the odd dry pint). I think in Germany, there's a minimum sale quantity for beverages, as well. ___ 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] gravity controlled pendulumn clock?
Arnold Tibus wrote: I don't understand at all the arguments against the metric system and the polemic remarks about. I second the statements of Neville and Jim. Without these intelligent french Astronomers like Jean-Baptiste-Joseph Delambre, Pierre-François-André Méchain and J.J. Lalande (more infos: Ken Alder, The Measure of All Things), we would still have the severe problems they had centuries ago! Reading WIKIPEDIA, http://en.wikipedia.org /wiki/German_units_of_measurement, we find a good example of weird units (just for only a part of Germany): Before the introduction of the metric system in Germany, almost every town had its own definitions of the units shown below, and supposedly by 1810, in Baden alone, there were 112 different standards for the Elle around Germany. The metric system was a much-needed standardisation in Germany. This was not only a german problem, and we still have today some problems in the world in this area. Standardization is fine. Attempting to force the world's largest economy to bend to the wishes of Europe isn't fine. The US system has been standardized for more than a century, and works very nicely. Decimal inches, decimal pounds, and seconds is every bit as valid a measurement system as the equally arbitrary meter, kilogram and second. Decimal inches, decimal pounds, and seconds flies most of the airframes in the world, won WWII, and took mankind to the moon and beyond. Saying that the use of pounds, and yards is imprecise is simply ignorant. I believe we should think more about what we are saying and doing, so we would do a big step forward to become a world community. ... Regardless of our measurement systems, we are already a world community. The strife we see in the world today is not the result of measurements, but rather is the result of religion, politics, and culture. -Chuck Harris ___ 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] On topic (sort of): odd units of measure
The good Lady Heather can display temperature values in all sorts of archaic measurement systems. And buried in there somewhere (I think its still there) can display phase errors in femtofortnights. I once worked for a company famous for its insistence on endless specs and paperwork that nobody ever read. I wrote a spec for a board where all the times were in ffn. It was years before anybody asked what an ffn was. ___ 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] filtering a 10Mhz frequency standard?
Come to think of it, you will have more noise if you use a LPF rather than a BPF, given noise being proportional to the square root of bandwidth. ___ 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] gravity controlled pendulumn clock?
cfhar...@erols.com said: Standardization is fine. Attempting to force the world's largest economy to bend to the wishes of Europe isn't fine. The US system has been standardized for more than a century, and works very nicely. Decimal inches, decimal pounds, and seconds is every bit as valid a measurement system as the equally arbitrary meter, kilogram and second. Decimal inches, decimal pounds, and seconds flies most of the airframes in the world, won WWII, and took mankind to the moon and beyond. I don't think force is the right word. Rather, it's a simple mater of voting with their pocketbook. The US may be the world's largest economy if you sort by country, but the total GDP of the countries using metric far outweighs all the others. The economy has shifted from local to global. If we want to sell our stuff to the rest of the world it will be easier/cheaper/better if the stuff we are trying to sell fits their measurement system. A friend used to tell the story of Sri Lanka being the number 2 or 3 country using non-metric. What does Britain use to measure bolts? (rather than beer) If anybody has recent info, please update me/us. (My memory could well be wrong, but it was something close to that.) -- Years ago (20-30?) a friend who worked for Ford reported that all new design work was using metric. They weren't dumping the old stuff, just not doing any new designs. (Most of?) The silicon industry shifted to metric for packages many years ago. Yes, drawings are often dual dimensioned. -- If you were an alien landing on Earth for the first time, which system would make more sense to you? I have a set of metric wrenches from Sears that are at least 30 years old. My local hardware stores stock metric screws. Their collection probably isn't as good as their non-metric stuff, but it's a good start. I'm in Silicon Valley. Many years ago (20-30?), a friend told me about a store named Mr Metric. They sold metric screws/bolts/nuts. That was back before ordering over the net was even on the radar. The point was that they could get anything and stocked most stuff you were likely to need. If you needed a metric bolt for your car, they had it in stock. http://www.mrmetric.com/ -- 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.
