[time-nuts] Shameless plug...
For those of you who are going to be in Dayton, Ohio, next weekend for Hamvention, please read this. Thanks for allowing me to post this. Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx A new feature at Hamvention this year will be the Discover Homebrew demo area, in the North Hall. Sponsored by Hamvention, and supported by the members of the Midwest VHF/UHF Society (MVUS), the demo area will provide you with an opportunity to show off your project(s) to everyone at the show. Located in booths 179,180,191,192,203,204, 215, and 216, there will be at least 8 long tables available to accommodate a number of homebrewers at once. Also, we will provide AC power and HF (and possibly VHF) antenna access for you. The demo area will be available during the Inside Exhibits open hours on Friday and Saturday. This is intended to be a very informal activity so that you can have casual conversations and answer questions with the people who stop by. The Discover Homebrew demo area is open to everyone, so if YOU have something you would like to show off, BRING IT! The demo area will operate on an open schedule basis, meaning that you can be there when you want for as long as you want, space permitting. We will have a sign-in sheet where you can record your contact info and anything else you would like. We want to help people find you if they have questions or missed your demo.For those with a lot of ambition, we will provide space for you to leave handouts about your creation. If you have commercial plans for your project, go ahead and talk about them, but please, no active selling. If you have any questions, concerns, or suggestions (Hey, this is our first crack at it, so we expect to learn a thing or two in the process), please contact us at exhib...@hamvention.org. ___ time-nuts mailing 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] And you thought you were old
Yep...built my first radio with one of those. $7.50 then is what, about $150 today? 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 John Green Sent: Tuesday, April 20, 2010 9:30 AM To: time-nuts@febo.com Subject: [time-nuts] And you thought you were old Anyone remember the CK722 transistor? As I remember they were about $7.50, a considerable sum. ___ time-nuts mailing 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] And you thought you were old
Now you have me trying to remember who made them...Raytheon? 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 jmfranke Sent: Tuesday, April 20, 2010 9:43 AM To: time-nuts@febo.com Subject: Re: [time-nuts] And you thought you were old I still have a dozen or more unused CK722 transistors. John WA4WDL -- From: John Green wpxs...@gmail.com Sent: Tuesday, April 20, 2010 9:29 AM To: time-nuts@febo.com Subject: [time-nuts] And you thought you were old Anyone remember the CK722 transistor? As I remember they were about $7.50, a considerable sum. ___ time-nuts mailing 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] Yukon Energy causes time sync problems
Let me see if I've got this straight... The article talked about the locals losing time, hence not as many hours in the day in my interpretation. So the line monitor clock was running fast, as were the clocks of the locals, thus completing 24 hours in something less than that. So far, so good? Now, if the monitor clock was developing bad bearings, thus causing it to run slow, the 'frequency manager' guy would see by comparison to the alleged GPS clock that he needed to crank up the generator RPM's to make up for the apparently slow line frequency. He may have also cranked in a little extra to make up for his perception that they were behind on their 24 hour obligation of 60x60x60x24 (=5184000) cycles per day. (I wonder if they have a chart to tell them how many rpm's to add to make up the shortfall, courtesy of some long forgotten EE who actually understood what was going on and could do the math?) Eventually, someone noticed in the outside world that tempus fugit, and the investigation spotted the fast line monitor clock and the high line frequency. So now the line frequency needs to be reduced below 60 Hz for quite a while maybe to bring everything back to where it should be. Being a somewhat small town, news travels fast and there probably isn't a lot local fluff to print anyway, so it made the paper. But actually, the newspaper article was done to tell the locals to reset their clocks so that the power company wouldn't have to run slow for however long it needed, and avoided further inconvenience to the citizenry. If the local papers in any major metropolis ever got wind of such sloppy frequency control, it would make the Toyota recall story look about as important as one of the editor's frequent grammar errors, while they proclaimed a conspiracy by the power company higher ups to cut down on fuel expenses, cheat on the environmental rules, and inflate usage to bilk consumers, not to mention the government's lax oversight and slow response to the 'crisis'. OK, sorry for that last cynical rant...well, a little sorry anyway. 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 Thomas A. Frank Sent: Saturday, April 10, 2010 12:52 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Yukon Energy causes time sync problems In this case, the reference clock appears to refer to GPS satellite time, but uses a standard wall clock to display it. It is the reference clock that slowed down when it should have failed to work at all. Perhaps the wall clock (maybe it was really a HP 113) needed oil. There's the real question for time nuts: How did the reference clock slow down? I just went and re-read the article. It reads to me that the synchronous clock, not the GPS reference clock, was what suffered the problem. --- quote: The control centre's wall clock was running faster than the satellite clock over the last few days, so staff simply turned down generation as they normally do, without knowing there was an internal problem with their electric clock, he explained. Morgan said when the generation was turned down, electric clocks that were plugged into the wall - alarm clocks, stove clocks, microwave clocks - all slowed down. The change was quite slow and unnoticeable until several minutes had been lost over a few days, he said. --- Or do y'all think I am misinterpreting the story? Easier to believe that the synchronous clock went bad than the GPS clock. On a related note, I visited a remote navy base once and went to talk to the folks running the station power plant, which was comprised of 24 very large diesel generators. They had a $2 synchronous clock sitting next to a $2 battery operated quartz wall clock, and were manually controlling the frequency. I suggested that they at least get a high quality quartz clock, if not a GPS based clock for the reference...but that costs money, so they weren't planning to change. Also related, I have an Electro Industries frequency meter that I use to monitor the power line here in Rhode Island. I have never seen it vary more than .05 Hz from nominal (59.95 to 60.05). On the other hand, during a trip to Scotland, the power frequency went fully 0.5 Hz out, from 49.50 - 50.50, Hz while I was there. In both cases, the average is right on over the course of several days. Tom Frank, KA2CDK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Symmetricom 5115A Phase Noise Allen Deviation TestSet on ePay
Luis... My wife is a great bargain hunter, and loves to come home and tell me how much money she has saved on something she just bought. I've been trying to get her to express the savings in dB$, but she just isn't going for it. Any mention of the word logarithm sends her into serious inattention to anything else I say. I need help! I can't deal with these quantities in non-dB terms! :-). Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: Luis Cupido [mailto:cup...@mail.ua.pt] Sent: Wednesday, April 07, 2010 10:32 AM To: thol...@woh.rr.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Symmetricom 5115A Phase Noise Allen Deviation TestSet on ePay Hi Tom, 10log I have no doubts that money=power... from years of personal experience of little power ;-) ;-). Luis Cupido. ct1dmk. Tom Holmes, N8ZM wrote: Hi Luis... Is that based on 10Log, or 20Log? I'm thinking Money = Power ;-). 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 Luis Cupido Sent: Wednesday, April 07, 2010 9:36 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Symmetricom 5115A Phase Noise Allen Deviation TestSet on ePay about 16dB down (I think). :-) lc ct1dmk. Steve Rooke wrote: Ah! but is it cheaper than US $15,865.00? On 8 April 2010 01:05, Luis Cupido cup...@mail.ua.pt wrote: BTW, I have this recently developed for another application http://w3ref.cfn.ist.utl.pt/cupido/dl/050.jpg it has all it takes to make that type of instrument with all that performance or better. (2x100ms/s 16bit ADC, 40k FPGA and USB2 interface). (both clock and triggers can come externally from low PN sources)... 40ke Cyc III fpga has more than enough multipliers and etc for the sort of conversions and correlations needed... and the display and fancy interface would happen in the PC. Anyone feels attracted to do some coding ??? Luis Cupido ct1dmk. ___ time-nuts mailing 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] FS Symmetricom timing system
The definition of diminishing return? 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 Arthur Dent Sent: Wednesday, April 07, 2010 1:17 PM To: time-nuts@febo.com Subject: [time-nuts] FS Symmetricom timing system My wife has a very simple rule: she doesn't care what I buy as long as it's smaller than what I sell. ___ time-nuts mailing 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] New Most Accurate Clock
Brilliant! If we found a warehouse full of Unobtainium, would we have to change its name to Readiliobtainium? Or Notsorarium? 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 Tom Van Baak Sent: Thursday, April 01, 2010 3:29 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] New Most Accurate Clock I used the new google today and found that a new type of atomic clock has been developed which promises a revolution in timekeeping. Typically national physics laboratories, such as NIST in the United States, develop the most precise atomic clocks. But today the best clock comes from NUTS, a quiet but intense collection of clock enthusiasts, with too much time on their hands. Read the full story here: www.LeapSecond.com/unclock.htm /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] New Most Accurate Clock
I believe the fundamental particle of Aprilfoolarium is the phoolton. 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 Brooke Clarke Sent: Thursday, April 01, 2010 4:35 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] New Most Accurate Clock Hi Tom: I thought that was the atomic decay sequence, i.e.: Unobtainium (looses a proton)- Readiliobtainium Readiliobtainium (looses a proton)- Notsorarium Notsorarium (looses a proton)- Aprilfoolarium Tom Abbott (inventor of the Calculagraph) coined the phrase Time is Money, see: http://www.prc68.com/I/Calculagraph.shtml Have Fun, Brooke Clarke http://www.PRC68.com Tom Holmes, N8ZM wrote: Brilliant! If we found a warehouse full of Unobtainium, would we have to change its name to Readiliobtainium? Or Notsorarium? 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 Tom Van Baak Sent: Thursday, April 01, 2010 3:29 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] New Most Accurate Clock I used the new google today and found that a new type of atomic clock has been developed which promises a revolution in timekeeping. Typically national physics laboratories, such as NIST in the United States, develop the most precise atomic clocks. But today the best clock comes from NUTS, a quiet but intense collection of clock enthusiasts, with too much time on their hands. Read the full story here: www.LeapSecond.com/unclock.htm /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] Surplus Places...
Dayton Hamvention, May 14-16. Always lots of surplus equipment dealers in flea market. Good opportunity to haggle over price, see what you are buying in person, and see a lot of other junque as well. www.hamvention.org 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 Burt I. Weiner Sent: Wednesday, March 31, 2010 3:25 PM To: time-nuts@febo.com Subject: [time-nuts] Surplus Places... In the Southern, California - Los Angeles area, we have a place called Apex Electronics. Some of the prices in the past have been outrageous, but now seem to becoming more reasonable. Right now there seems to be a ton of NTSC TV stuffs coming in the doors. I think you could spend days foraging around at Apex. Here's a link that really doesn't even begin to do it justice: http://www.apexelectronic.com/ Burt, K6OQK Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net K6OQK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna splitters
Ashley... Regardless of how you ask your questions here, you can count on a complicated answer :-). Sorry guys, I couldn't resist. 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 ashle...@aol.com Sent: Friday, March 26, 2010 4:41 PM To: p...@b737.co.uk; time-nuts@febo.com Subject: Re: [time-nuts] GPS antenna splitters Thank you ! Ashley Thank You Kiss-Electronics Ms Ashley Hall 183 N 5th Avenue Cornelius, Oregon 97113 W7DUZ www.kiss-electronics.com -Original Message- From: Gerard PG5G p...@b737.co.uk To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Mar 26, 2010 1:37 pm Subject: Re: [time-nuts] GPS antenna splitters for a company called keep it simple you have a complicated way of asking questions ashle...@aol.com wrote: Hi Everyone After a lot of learning, sweating (yes, girls do sweat), hand wringing, and a LOT of emails and great help , we have two of Mr Miller (G3RUH) GPSDO units up and working fine. Disciplined 10mhz all over the place. Now what we need is a GPS antenna splitter. S, we're looking for links, do-it-yourself articles, hints from you guys who have built them.. Ebay is really barren for these things, only one or two listed, but I thought we would try Time Nuts first and see ... Thank you everyone for all of your help with this GPSDO project !! Ashley 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 mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna splitters
Dave, that's like my wife asking if her dress makes her butt look bigger...there is no answer that won't put me in the doghouse. Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: David C. Partridge [mailto:david.partri...@dsl.pipex.com] Sent: Friday, March 26, 2010 5:41 PM To: thol...@woh.rr.com; 'Discussion of precise time and frequency measurement' Subject: RE: [time-nuts] GPS antenna splitters Now you couldn't possibly be referring to Bruce Griffiths could you? :-) Cheers Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Holmes, N8ZM Sent: 26 March 2010 21:12 To: 'Discussion of precise time and frequency measurement'; p...@b737.co.uk Subject: Re: [time-nuts] GPS antenna splitters Ashley... Regardless of how you ask your questions here, you can count on a complicated answer :-). Sorry guys, I couldn't resist. 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 ashle...@aol.com Sent: Friday, March 26, 2010 4:41 PM To: p...@b737.co.uk; time-nuts@febo.com Subject: Re: [time-nuts] GPS antenna splitters Thank you ! Ashley Thank You Kiss-Electronics Ms Ashley Hall 183 N 5th Avenue Cornelius, Oregon 97113 W7DUZ www.kiss-electronics.com -Original Message- From: Gerard PG5G p...@b737.co.uk To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, Mar 26, 2010 1:37 pm Subject: Re: [time-nuts] GPS antenna splitters for a company called keep it simple you have a complicated way of asking questions ashle...@aol.com wrote: Hi Everyone After a lot of learning, sweating (yes, girls do sweat), hand wringing, and a LOT of emails and great help , we have two of Mr Miller (G3RUH) GPSDO units up and working fine. Disciplined 10mhz all over the place. Now what we need is a GPS antenna splitter. S, we're looking for links, do-it-yourself articles, hints from you guys who have built them.. Ebay is really barren for these things, only one or two listed, but I thought we would try Time Nuts first and see ... Thank you everyone for all of your help with this GPSDO project !! Ashley 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 mailing 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] nubie querie
tvb... Not to kick sand in your face, but it seems that in order for your automated turn-over device to work, as well as to accurately measure the time intervals, you would need a means to determine when the sand quits flowing. Possibly an accelerometer or microphone, with the added benefit of being able to hear the close-in phase noise. I admire your dedication to monitoring the hour long periods of the sand timer so diligently. Truly a time-nut! 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 Tom Van Baak Sent: Friday, March 05, 2010 1:44 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] nubie querie In the last slide you show a sand timer. Do you have accuracy data for it? Hi Brooke, The past 3 hours the one hour timer measures 56:24, 56:19, and 56:30. That's at 67 F room temp. Somewhere I have enough clean data to compute the ADEV; it's more stable than accurate. It also has a tempco (one day when my wife wasn't looking I collected data inside the kitchen refrigerator, and oven). I would guess it has very little dependence on barometric pressure or humidity since all the sand is sealed inside the blown glass bulb. Eventually I will mechanically automate the hourly turn-over and get 24x7 long-term data. If I also model the tempco it may be possible to temperature compensate the rate error. I don't know where the flicker floor will be. My prediction is this hour-glass will gradually speed up as the glass or the sand slowly wear over time. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] Primary Standards...
Dave... I went back and checked in my college Physics textbook, Halliday Resnick, Vol. II, circa 1960, and you are correct about the Ampere being defined based on the force between two parallel wires. However, HR does not specify a vacuum nor negligible wire cross section. The latter seems reasonable to minimize the effects of geometry. They also say that at the time, NBS was using a balance beam technique with a moving coil between two fixed coils as the primary measurement standard. Where Avogadro's number comes in is that 1 coulomb is defined as the amount of charge that flows through a given cross section of wire in one second IF there is a steady current of one Ampere. In other words, if I moved a coulomb of charge in one second, then the current must have been one Ampere. Kind of a strange way to state it given that one of the equations given for charge is Q= the integral of I*d(t), implying that current and time are the are the measurables. So I think in a way we are both correct: you have the definition of the standard, and I cited an equivalence that is based on the fundamental units of the mks system. In a table in the appendix called Symbols, Dimensions, and Units for Physical Quantities there are listed about 60 quantities and their primary units (Length, Mass, Time, and Charge). For example, capacitance has dimensions of T^2 * Q^2 / M^2 * L^2, with the derived unit Farad. Force has dimensions of M*L/T^2, with derived units of newtons. This fits with F=MA, that is, force is derived from mass, length, and time, all of which have fundamental standards. The Kg is a slug of something carefully stashed in a cave in France ( a little license here, please), the meter is a bunch of wavelengths of a Krypton dance, and the second is based on...oh, wait, this is the time-nuts forum. So what is bugging me is that the Newton, a derived unit, is being used to define the Ampere, which appears to be a fundamental part of the definition of the Coulomb, a primary unit. This strikes me as backwards. However, it does make sense that the method used to determine a 'standard' value for the Ampere might not be possible using such a strict dependency on direct ties to primary units. OK, I think I have meandered far enough OT once again as to put this to rest for now. 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 Dr. David Kirkby Sent: Tuesday, February 23, 2010 8:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Primary Standards... Tom Holmes, N8ZM wrote: My recollection of the definition of an Ampere is 6.02 x 10^23 electrons per second (Avogadro's Number, I believe) passing a point in a conductor. To this day, I wonder how they managed to count all those electrons. But it does suggest that the silver deposit approach might be a better method of building a standard. Seems, though, like you'd have to make a darned high resolution weight measurement. That certainly was not the definition I learned during my EE degree, and neither is it the one given on Wikipedia - not that I'd call Wikipedia a standard. My recollection is the same as Wikipedia's - though I could not remember the bit about it needing to be a vacuum. But if you stuffed mu-metal between the wires, it would tend to reduce the force, so I can well believe its defined in a vacuum. I think as someone else said, this depends on one's definition of a standard. There's no one standard definition of a standard (pun intended). 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. ___ time-nuts mailing 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] Primary Standards...
My recollection of the definition of an Ampere is 6.02 x 10^23 electrons per second (Avogadro's Number, I believe) passing a point in a conductor. To this day, I wonder how they managed to count all those electrons. But it does suggest that the silver deposit approach might be a better method of building a standard. Seems, though, like you'd have to make a darned high resolution weight measurement. Now with tongue still planted firmly in cheek, I have to think that THE primary standard time interval reference is whatever NIST (and other such outfits) tells me it is. Anything else would seem to be a secondary standard as it would have to be compared to NIST to be sure it is right (OK, its error to NIST is known), especially based on all of your comments. But as even NIST pointed out, primary vs. secondary seems to be in the context of the beholder. Thanks for the enlightening discussion; you've really encouraged me to think about this a bit. 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 Don Latham Sent: Tuesday, February 23, 2010 7:33 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Primary Standards... Gosh. I remember the ampere as the current that would deposit a given weight of silver in a fixed time... Also saw a note about one part in e-20. As the universe is apparently about 5e17 sec old, can we make a standard that is good to 1 sec in 1e20 sec??? Don Dr. David Kirkby David C. Partridge wrote: No they cannot be - yet. At the point where (e.g.) the second is re-defined in terms of the aluminium quantum clock, then the aluminium quantum clocks are then by definition the primary standards of time, and all the Cs clocks are now secondary standards as the second is no longer defined in terms of the Cs beam clock. Dave Does that mean that there is no primary standard for the Ampere? An Ampere is defined as the current which will produce an attractive force of 2 × 10–7 newtons per metre of length between two straight, parallel conductors of infinite length and negligible circular cross section placed one metre apart in a vacuum. Since its impossible to build such a system, does that mean there is no primary standard for an amp? 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. -- 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] 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] OT: HP 8590A
Joe... I had an 8590A a number of years ago, and was able to do a lot with it. As others have pointed out, it does tend to drift and the frequency accuracy, especially in the HF range, isn't that great, but that's why counters were invented. These guys were intended for the portable service market, such as cable TV and what passed for cell phone base stations 20 years ago. As others have mentioned, if the display is not badly burned and the input attenuator hasn't been popped, it should be a very useful tool for a lot of the things you would want to see. Yes, parts can be tough to get for it, so keep that risk in mind. My credo has long been that you should always take your first measurement with some skepticism until you have something to corroborate it. This is frequently called a sanity check. So if you can get it for a price that you think is reasonable for the condition, go for it. Any way to look at the spectrum content is better than nothing. 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 Joseph Gray Sent: Saturday, February 20, 2010 9:35 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT: HP 8590A Thanks to all for the advice. I agree with Said that a 8560E would be much nicer. However, I may be able to get this 8590A very inexpensively. Considering the price difference between this unit and a newer/better SA, I'm inclined to go with this one. I'm thinking of this as training wheels. Once I gain some hands on with a SA, I'll know better what I want in a future purchase. Joe KA5ZEC On Sat, Feb 20, 2010 at 5:20 PM, Bob Camp li...@cq.nu wrote: Hi There are drop in replacement video sections for some of the older instruments. It's not a duplicate of the original, but a form / fit / function sort of thing. I have no idea if there is one for the 8590. They still cost more than most of these gizmos sell for used. Bob On Feb 20, 2010, at 5:53 PM, Rick Karlquist wrote: The CRT's went out of production something like 20 years ago. The factory stock was exhausted long ago. Of course there could be NOS forgotten somewhere, like in a barn with a 1957 Chevy with 50 miles on it :-) Rick N6RK Lux, Jim (337C) wrote: And make sure the CRT has life left. On a lot of older units, either the faceplate is burned with the graticule and noise floor, or they're so dim that you have a hard time reading it. I suspect that replacement CRTs cost more than the whole used analyzer. On 2/20/10 11:27 AM, life speed life_sp...@yahoo.com wrote: Date: Fri, 19 Feb 2010 17:38:50 -0700 Subject: [time-nuts] OT: HP 8590A 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 I personally do not like these low-end spectrum analyzers. They have poor dynamic range and phase noise performance. However, I design microwave circuits for a living and can be a test equipment snob. If you think it is adequate for your purposes, I would at least connect it to a calibrated signal generator and verify amplitude accuracy is within 3 dB. Most old spec ans I have seen are way off, even broken. Still show a signal on the display, but not very helpful. Also check for spurious across many frequencies. 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. ___ time-nuts mailing 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
Re: [time-nuts] More IKEA hardware...
While we are briefly back on the subject of IKEA, I recall someone commenting that IKEA does not do web sales. According to the catalog my better half received a couple of weeks ago, in the States it is www.ikea-usa.com for web sales. But I admit I haven't tried it out, yet. 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 Poul-Henning Kamp Sent: Monday, February 01, 2010 7:17 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] More IKEA hardware... http://wiki.eth-0.nl/index.php/LackRack (Please try to avoid a long wandering thread on this one...) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] More IKEA hardware...
Hi Brooke... Ah, so I see. Curious that they have 200+ in stock at the store 40 minutes away from me. Maybe they don't ship cheaply or without high risk of breakage. But enough conjecture for this reflector; on to the fun stuff! Thanks! Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: Brooke Clarke [mailto:bro...@pacific.net] Sent: Monday, February 01, 2010 3:55 PM To: thol...@woh.rr.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] More IKEA hardware... Hi Tom: You can NOT order lamps in the U.S on line. Have Fun, Brooke Clarke http://www.PRC68.com Tom Holmes, N8ZM wrote: While we are briefly back on the subject of IKEA, I recall someone commenting that IKEA does not do web sales. According to the catalog my better half received a couple of weeks ago, in the States it is www.ikea-usa.com for web sales. But I admit I haven't tried it out, yet. 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 Poul-Henning Kamp Sent: Monday, February 01, 2010 7:17 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] More IKEA hardware... http://wiki.eth-0.nl/index.php/LackRack (Please try to avoid a long wandering thread on this one...) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Low temperature coefficient capacitors for DMTD
And if my recollection from my days running a product validation lab many years ago is correct, the failure mode of most polycarbonate caps was shorted and flaming. 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 Poul-Henning Kamp Sent: Monday, January 25, 2010 5:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Low temperature coefficient capacitors for DMTD In message 20100125.140436.3508.5.cdel...@juno.com, Corby Dawson writes: Most manufacturers no longer make polycarbonate capacitors. The advent of CD's made polycarbonate ridiculously expensive and priced them out of the market... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] HP10811 losing EFC
While on the subject of 10811's, I have one which appears to have a blown fuse. Bypassing same, it seems to work OK, so suspect that tiny filament or whatever simply succumbed to some shock or vibration, or maybe just old age. I don't recall the current draw now, but it seemed reasonable at the time, and it came up on frequency and appeared to be controlling the oven temp OK. Would like to replace the fuse with something more correct than a #22 before I let it go online full time. Any ideas for where to get replacement, or a suitable substitute? Thanks. This is a fun list to monitor. I learn more in a day here than anything else I've ever done. 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 Rick Karlquist Sent: Friday, January 15, 2010 7:54 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP10811 losing EFC No one has mentioned the fact that the cathode of the varactor is connected to an internal 6.8V Zener diode voltage reference. This is another source of trouble. Rick Karlquist N6RK Bob Camp wrote: Hi I sure would do some quick continuity checks on the EFC line before I started swapping varicaps out. A bum solder joint opening up is a lot more likely than the varicap going nuts in a fashion that still lets the oscillator run. Bob On Jan 15, 2010, at 7:08 PM, Neville Michie wrote: Hi, I have two HP10811 oscillators that do not respond to EFC voltage. The latest to fail had been quite accurately set against a TBOLT, one morning (after being on standby in a HP5328A) it was off frequency and would not shift with EFC but would adjust with the coarse adjust. I have bought in two Phillips varicap diodes, BBY40 and BB149A, but before I did some damage fault finding in the HP10811s I thought it wise to ask for any advice that was available. While I am playing with them I may try to readjust the temperature setting of the oven to get on top of the turnover. Can anyone point me to that article? 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 mailing 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] HP10811 losing EFC
HI Rick... That helps a lot. It also tells me the real reason why the fuse is open ;-(. Thanks! Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx -Original Message- From: Rick Karlquist [mailto:rich...@karlquist.com] Sent: Friday, January 15, 2010 8:48 PM To: thol...@woh.rr.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP10811 losing EFC Tom Holmes, N8ZM wrote: While on the subject of 10811's, I have one which appears to have a blown fuse. Bypassing same, it seems to work OK, so suspect that tiny filament or whatever simply succumbed to some shock or vibration, or maybe just old age. I don't recall the current draw now, but it seemed reasonable at the time, and it came up on frequency and appeared to be controlling the oven temp OK. Would like to replace the fuse with something more correct than a #22 before I let it go online full time. Any ideas for where to get replacement, or a suitable substitute? Thanks. This is a fun list to monitor. I learn more in a day here than anything else I've ever done. Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx The fuse in an interesting topic. It is a thermal fuse, not an electrical one. It deals with oven failure. It does not prevent the oven from failing, but rather limits the amount of damage and smoke if the oven runs away. The main purpose is to limit toxic outgassing, rather than to protect the oscillator, although it may accidentally do that. I have never heard of a case of an oven running away, although it is theoretically possible, for example, if the thermistor is open or disconnected. (I have never heard of a thermistor failing either for that matter.) The fuse cannot be soldered in for the obvious reason that it cannot tolerate solder temperatures. It is instead inserted into a non gold plated socket. In 99+% of fuse failures, the fuse has not blown (as can be confirmed with an ohmmeter) but instead is not making contact. You might see if your fuse is still good. In any event, I recommend bypassing the fuse with a jumper and not worrying about it. There is far more chance of the fuse failing than the oven running away. Rick Karlquist N6RK ___ time-nuts mailing 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] Trimble GPS RX info needed
Have obtained a Trimble P/N 23632-20 device which appears to be a GPS of the type often seen mounted on a pole at a cell site. A search of the web has not been successful in providing the connections or other info. The connector is a small 12 pin type, possibly an ITT/Cannon. The unit is housed on a plastic (for the purists, polymer) snap together case, which I have so far been unable to open, as it appears that all 8 tabs must be released simultaneously to accomplish that feat. Any help would be appreciated. Thanks. Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx ___ time-nuts mailing 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] Trimble info needed...
Thanks guys! That was very useful! Regards, Tom Holmes, N8ZM Tipp City, OH EM79xx ___ time-nuts mailing 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] Rubidium standard
From my experience as a Design Validation Lab manager, MTBF and its equivalents were never more than a method for comparing the design revisions. The relationship to reality is quite bogus unless your tests are an exact replication of the world the item will experience. Cost and available time, not to mention the fact that each unit will have a different life experience ( just like people), makes testing in the actual environment difficult, and renders any extrapolation of test results to reality an exercise in fantasy. Which explains why the marketing and upper management types love it. Most testing that produces MTBF figures is also based on hitting the extremes of the environment such as temperature, rate of change of temperature, and humidity. These usually are only loosely related to reality, but are based, hopefully, on some real world data. It is the correlation factor that is suspect. My contention is that MTBF is only valid when based on data from the units operating in the field, and is essentially after-the-fact. By that time, what's done is done. If you have real world experience with a statistically valid number of units, then you can determine MTBF with some confidence. Otherwise, it is just a SWAG. But it can be a useful SWAG for comparison purposes. Frankly, I would distrust any outfit that puts it into their advertising without some sort of disclaimer regarding how it was determined, and the ubiquitous YMMV. 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 Alan Melia Sent: Wednesday, November 18, 2009 9:27 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Rubidium standard The big problem with MTBF is that it doesnt really mean ANYTHING if you invoke the proper statistical properties of the calculation! It is a process dreamed up out of thin air by Military and other users who felt they needed an index of quality and at least some life testing on the product they were buying without elevating the price too much, as proper life tests would. Mathematically it is highly suspect, but that depends on how the figures are used and most involvedmanagement level :-)) dont understand Statistics... so they are invariably mis-used ! Alan G3NYK - Original Message - From: Mike S mi...@flatsurface.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, November 18, 2009 12:54 PM Subject: Re: [time-nuts] Rubidium standard At 05:22 AM 11/18/2009, Steve Rooke wrote... The point I should have made is that most quoted MTBF figures have a reasonable bearing on the lifetime of the item, But your point would then be almost perfectly incorrect. MTBFs are not meant to, nor do they, predict product lifetimes. They are measures/predictions of product reliability. What does MTBF have to do with lifetime? Nothing at all! - http://www.ece.cmu.edu/~ganger/ece546.spring02/readings/mtbf.description MTBF represents the statistical approximation of how long a number of units should operate before a failure can be expected. It is expressed in hours and does not represent how long the unit will last. - Learn (or review) the difference between MTBF and lifetime, Control Engineering, 9/24/2008; http://www.controleng.com/article/312365-Learn_or_review_the_difference_betw een_MTBF_and_lifetime.php I don't grant Wikipedia strong authority, but it is useful, and has this to say: MTBF is commonly confused with a component's useful life, even though the two concepts are not related in any way. For example a battery may have a useful life of four hours, and an MTBF of 100,000 hours. These figures indicate that in a population of 100,000 batteries, there will be approximately one battery failure every hour during a single battery's four-hour life span. There's much more out there, if you make the effort. I felt that an example based on humans was not really applicable to the real world of electronic items but that is my own opinion and I'm happy if you disagree with me. MTBFs are not exclusive to electronics. Statistics, math and MTBFs are objective matters, so your opinion really doesn't make any difference. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] Getting GPIB to work on HP5382B Universal counter
Jerome... I can appreciate the frustration you are experiencing with this. I don't like to do much programming anymore because of so many undocumented rules and procedures needed to make things work that ought to be simple. However, in your case, I think I can be of some help. The Agilent IO Libraries will load and peacefully coexist with the NI libs, as they are designed that way. You can even specify one or the other as primary. Personally, I'd make the Agilent version primary, as you are using their hardware. I believe that NI's can only function as primary. Interestingly, Agilent's IO Libs make an effort to support most NI hardware and work with LabView, and NI reciprocates a little. So in many cases, you can get by with just one installed. Agilent's Connection Expert should not only see the 82357A and 83250, but you should also be able to see or add the 5382B as being connected to one of those. Personally, I'd go with the USB/GPIB adapter, if only for convenience. Once you can see the counter in the Agilent CE, you can send commands to it. As one writer mentioned, you need to enter the correct commands for your box, as the ones listed in CE are to the newer standards, such as SCPI. If you enter a command that requires reading back data, there is a command that both sends and reads. Even a data array can be read back through CE and displayed in the window. If you are able to make that work satisfactorily, then your program should just need to point to the name of the IO device, usually gpib0, or in some cases, to the name of the instrument once you have it defined in your program. VEE does this very nicely, and I'm sure that LabView has similar capability. VB may require a more explicit identification in each IO command. Hope this helps. If you still have trouble, ping the list again. 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 Jerome Peters Sent: Wednesday, October 14, 2009 6:16 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Getting GPIB to work on HP5382B Universal counter I have not yet met with success, but I have a little more experience ;) Since so many people have made helpful suggestions, I thought I'd include the current status. Just downloaded the most recent version of NI-488.2 version 2.5 off the NI website. It downloaded/unzipped/installed without any apparent issue. The Devices and Interfaces - Measurement Automation Explorer shows several different applications in the software tree, but does not recognize either of the two HP-IB interfaces that are installed/attached: - USB to HPIB (Agilent 82357A) - PCI to HPIB (HP 82350) I did go back to the Agilent Connection Expert (it still sees the two devices) I did check the Enable Agilent GPIB cards for 488 programs The MS Win XP Device Manager sees both of them. I did learn that you cannot just re-install NI-488.2 from the downloaded zip file, but have to use the MS software uninstall process first. Still no joy in recognizing the interface card(s) Thanks again Regards, Jerome KC6ENE -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David C. Partridge Sent: Wednesday, October 14, 2009 2:27 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Getting GPIB to work on HP5382B Universal counter Dave, I don't remember being your college tutor on this - in fact I never was a college teacher, but what you've laid out below is pretty much what I taught all the trainee programmers I had.You've done a very good job of putting it in a nutshell. The objective of the whole is to achieve understandability so that the next poor sap (this might be you two years later) who comes along to work on this thing (whatever it is) can get stuck in to fix it without having to reverse engineer the thought processes of the original author. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Dave Baxter Sent: 14 October 2009 10:15 To: time-nuts@febo.com Subject: Re: [time-nuts] Getting GPIB to work on HP5382B Universal counter Hi... I use mostly NI GPIB cards adapters, but from the little work I've done with the HP/Agilent stuff, I think the same overall principle applies, re software development for instrument control. First step... Install the USBGPIB adapter drivers, tools and utilities Exactly as the instruction say to for whatever OS you are running. Run and verify any diagnostics they supply too. If anything does not work as expected, find out what and why. Then, in the folder tree all that will probably create somewhere on your system, there will be some documentation, and probably some worked examples in various languages, VB, C, Delphi etc, as to how to do the basic (as in simple) IO communication stuff. NI
