Re: [time-nuts] Ebay FE-5680A Rb: Connections and Features
In a message dated 12/12/2011 04:00:17 GMT Standard Time, smit...@c-c-i.com writes: But you can query the unit and it will reply with the programmed offset value. If you get it wrong, it won't accept the programmed value. Just query it with: 2d 04 00 29 to verify the offset value. - Yes I know, that's in the manual anyway, but if you do get it wrong and there's no response it might not be immediately obvious where the problem lies, wrong software, wrong settings, or wrong connection for example, so was just trying to offer some quick start up information for anyone who might need it. 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] Subs for obsolete chips in pictic
The 74HC series can handle 6V levels too. The 74HCT series is a 5V logic family. On Sun, Dec 11, 2011 at 9:38 PM, Stanley timen...@n4iqt.com wrote: The 74AC175 can not be subituted as the circuit needs the higher voltage output, contact me off list if you need a few parts, or use the surface mount PC board as these parts are still around. See options here : http://www.ko4bb.com/dokuwiki/**doku.php?id=precision_timing:**pictichttp://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:pictic Stanley - Original Message - From: Azelio Boriani azelio.bori...@screen.it To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, December 11, 2011 2:15 PM Subject: Re: [time-nuts] Subs for obsolete chips in pictic Better use 74HC or 74HCT parts, the 74F should be TTL FAST parts that require high input current to be driven correctly. On Sun, Dec 11, 2011 at 9:04 PM, Chris Albertson albertson.ch...@gmail.com**wrote: Looking at the picric II schematic. Trying to decide on the bet substitute parts for some obsolete parts. It uses a few 74ACxxx locic family parts that are no longer made. I think the 74H or 74F series should work What do you think? I may have to adapt an SMD part. They have to work on 5V supply and the clock is 10MHz. There is also a discontinued op amp but they are easy to sub. -- 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-nuts and follow the instructions there.
Re: [time-nuts] Subs for obsolete chips in pictic
Better use 74HC or 74HCT parts, the 74F should be TTL FAST parts that require high input current to be driven correctly. HC/HCT are pretty slow. I'd carefully check the data sheet timings before substituting for AC. Yes, F/FAST requires some input current, but I wouldn't call it high. It's higher than CMOS but might work in some cases. Again, check the data sheets. (Or try it for a low volume project.) -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Subs for obsolete chips in pictic
Yes, your're right: higher than CMOS, I was too high. On Mon, Dec 12, 2011 at 10:53 AM, Hal Murray hmur...@megapathdsl.netwrote: Better use 74HC or 74HCT parts, the 74F should be TTL FAST parts that require high input current to be driven correctly. HC/HCT are pretty slow. I'd carefully check the data sheet timings before substituting for AC. Yes, F/FAST requires some input current, but I wouldn't call it high. It's higher than CMOS but might work in some cases. Again, check the data sheets. (Or try it for a low volume project.) -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gravity controlled pendulumn clock?
Jim Lux writes: intriguing. From your parenthetical remark, I'm assuming you move the whole assembly up and down to adjust the speed? I was thinking about a huge mass that moves around? Got one already -- it's called the moon! let's see.. period is proportional to sqrt(1/g) g is proportional to 1/r^2, so period is proportional to r. Earth is roughly 7000 km radius, so moving it 1 meter higher or lower changes the period by 1part in 7million... interesting. Yes, cool isn't it? There's an entire history of using pendulums to measure altitude, and latitude -- and time or distance: at some locations on earth a 1 meter pendulum is so close to a 1 second beat there was consideration to define the meter that way. Some articles on gravity, earth tides, and pendulum clocks: http://www.leapsecond.com/hsn2006 John Allen writes: Hi Tom - what is HSN? Horological Science Newsletter, http://www.hsn161.com It's a collection of people who still find precision pendulum clocks fascinating, a specific strain of the time nut disease. It's a small group (officially Chapter #161, Horological Science) of the larger: National Association of Watch Clock Collectors, http://www.nawcc.org /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Subs for obsolete chips in pictic
On Sun, 11 Dec 2011 12:04:35 -0800 Chris Albertson albertson.ch...@gmail.com wrote: It uses a few 74ACxxx locic family parts that are no longer made. This surprises me a bit. Do you have any references to EOL notices from the manufacturers? Yes, they are not as easy to find as they used to be, but that's mostly because less and less people use them. But i'd be really suprised if we already reached the level where they are not worth to be produced anymore. Other than that, check findchips.com. There you can find which of the big distributors has what chips on stock. Oh.. and if you choose SMD varinats instead of DIL, then you get more selection. Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing 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] Subs for obsolete chips in pictic
On Mon, Dec 12, 2011 at 4:28 AM, Attila Kinali att...@kinali.ch wrote: On Sun, 11 Dec 2011 12:04:35 -0800 Chris Albertson albertson.ch...@gmail.com wrote: It uses a few 74ACxxx locic family parts that are no longer made. This surprises me a bit. Do you have any references to EOL notices from the manufacturers?. Other than that, check findchips.com. Thanks. The findchips.com suggestion was good. Seems the 74AC part really is not available but there is a CD74ACxxx part that looks good. The problem is, the PCB is already made so it is hard to adapt the design to other parts. If I were designing from scratch I'd only select parts that were stocked in high volume by most distributers -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Subs for obsolete chips in pictic
Hi The part went gone with the wind right as the board was being released Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Albertson Sent: Monday, December 12, 2011 12:42 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Subs for obsolete chips in pictic On Mon, Dec 12, 2011 at 4:28 AM, Attila Kinali att...@kinali.ch wrote: On Sun, 11 Dec 2011 12:04:35 -0800 Chris Albertson albertson.ch...@gmail.com wrote: It uses a few 74ACxxx locic family parts that are no longer made. This surprises me a bit. Do you have any references to EOL notices from the manufacturers?. Other than that, check findchips.com. Thanks. The findchips.com suggestion was good. Seems the 74AC part really is not available but there is a CD74ACxxx part that looks good. The problem is, the PCB is already made so it is hard to adapt the design to other parts. If I were designing from scratch I'd only select parts that were stocked in high volume by most distributers -- 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] FE-5680A internal signal waveforms (60, 30, 10 MHz)
I have two of the FE-5680A (FEI P/N 217400-30352-1) Rb references, and I'm looking at the signals on digital side of the PCB inside, in particular the Xilinx CPLD, that is the XC9572XL in a 64-pin package. Here is a photo with the signals marked: https://picasaweb.google.com/109928236040342205185/FE5680A#5685304134718133138 pin 64 has a nice looking 60.00 MHz sine wave, I gather this is the input signal to the CPLD. pin 22 has a 30 MHz square wave, although it has some ripples (see scope trace in same Picasa album) pin 49 has a 10 MHz square wave but with a very odd shape. Pin 49 is the signal which is LC filtered (?) to become the 10 MHz sine wave out on the internal J8 mini-connector, and the external DB9. The signal is about 3.3 Vpp, but becomes an 11 Vpp sine wave at the far side of a blue part (inductor?) marked 2R2J. The 10 MHz sine out on my unit has some noticeable amplitude noise, at least a few %. Since I'm only using the signal as a digital clock, I prefer a square wave, assuming the fast edge will give me lower jitter. A 200 MHz Rigol scope reads a risetime of 2 ns on CPLD pin 49, but the waveform looks so noisy and odd (see below), maybe I would be better off just squaring up the output sine. ...maybe if pin 49 was disconnected from the sine output filter, it would be more square (?) https://picasaweb.google.com/109928236040342205185/FE5680A#5685304143859526258 -John Beale ___ time-nuts mailing 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 internal signal waveforms (60, 30, 10 MHz)
Was the probe grounded using a spring clip off the probe tip, hitting the nearest ground that is tied directly to the 9572? If not, the waveform captured is not the waveform present during operation. Also, using a 10pF probe on a 2ns risetime signal is quite a heavy load / impedance mismatch. I've used 100:1 low capacitance probes (Zin = 5000 Ohms, Cin = 2pF or less) to mitigate that problem at less cost than a good FET probe. I also suspect the filter impedance is not constant versus frequency, leading to additional distortion of the square wave. Bob LaJeunesse From: beale be...@bealecorner.com To: time-nuts@febo.com Sent: Mon, December 12, 2011 1:29:24 PM Subject: [time-nuts] FE-5680A internal signal waveforms (60, 30, 10 MHz) ... A 200 MHz Rigol scope reads a risetime of 2 ns on CPLD pin 49, but the waveform looks so noisy and odd (see below), maybe I would be better off just squaring up the output sine. ...maybe if pin 49 was disconnected from the sine output filter, it would be more square (?) https://picasaweb.google.com/109928236040342205185/FE5680A#5685304143859526258 -John Beale ___ time-nuts mailing 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 internal signal waveforms (60, 30, 10 MHz)
Hi If you are getting 11 V p-p, I'd bet you don't have the 10 MHz output terminated in 50 ohms. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of beale Sent: Monday, December 12, 2011 1:29 PM To: time-nuts@febo.com Subject: [time-nuts] FE-5680A internal signal waveforms (60, 30, 10 MHz) I have two of the FE-5680A (FEI P/N 217400-30352-1) Rb references, and I'm looking at the signals on digital side of the PCB inside, in particular the Xilinx CPLD, that is the XC9572XL in a 64-pin package. Here is a photo with the signals marked: https://picasaweb.google.com/109928236040342205185/FE5680A#56853041347181331 38 pin 64 has a nice looking 60.00 MHz sine wave, I gather this is the input signal to the CPLD. pin 22 has a 30 MHz square wave, although it has some ripples (see scope trace in same Picasa album) pin 49 has a 10 MHz square wave but with a very odd shape. Pin 49 is the signal which is LC filtered (?) to become the 10 MHz sine wave out on the internal J8 mini-connector, and the external DB9. The signal is about 3.3 Vpp, but becomes an 11 Vpp sine wave at the far side of a blue part (inductor?) marked 2R2J. The 10 MHz sine out on my unit has some noticeable amplitude noise, at least a few %. Since I'm only using the signal as a digital clock, I prefer a square wave, assuming the fast edge will give me lower jitter. A 200 MHz Rigol scope reads a risetime of 2 ns on CPLD pin 49, but the waveform looks so noisy and odd (see below), maybe I would be better off just squaring up the output sine. ...maybe if pin 49 was disconnected from the sine output filter, it would be more square (?) https://picasaweb.google.com/109928236040342205185/FE5680A#56853041438595262 58 -John Beale ___ time-nuts mailing 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 12/12/2011 01:37 AM, Jim Lux wrote: On 12/11/11 4:04 PM, Tom Van Baak wrote: GCPC -- gravity controlled pendulum clock (elevation) intriguing. From your parenthetical remark, I'm assuming you move the whole assembly up and down to adjust the speed? I was thinking about a huge mass that moves around? let's see.. period is proportional to sqrt(1/g) g is proportional to 1/r^2, so period is proportional to r. Earth is roughly 7000 km radius, so moving it 1 meter higher or lower changes the period by 1part in 7million... interesting. Hmm... how does the near-field gravitational pull behave? The far-field is surely r^-2, but wonder about the near-field effect. Need to grab some paper and pen and convince myself. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ebay FE-5680A Rb: Connections and Features
Realterm is a good one too: http://realterm.sourceforge.net/ Cutecom works perfectly: http://cutecom.sourceforge.net/ inline: image001.gif___ time-nuts mailing 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?
Hi If you have a mountain nearby, it does indeed impact the local field. I believe they first measured that in the 1700's. Bob On Dec 12, 2011, at 5:19 PM, Magnus Danielson wrote: On 12/12/2011 01:37 AM, Jim Lux wrote: On 12/11/11 4:04 PM, Tom Van Baak wrote: GCPC -- gravity controlled pendulum clock (elevation) intriguing. From your parenthetical remark, I'm assuming you move the whole assembly up and down to adjust the speed? I was thinking about a huge mass that moves around? let's see.. period is proportional to sqrt(1/g) g is proportional to 1/r^2, so period is proportional to r. Earth is roughly 7000 km radius, so moving it 1 meter higher or lower changes the period by 1part in 7million... interesting. Hmm... how does the near-field gravitational pull behave? The far-field is surely r^-2, but wonder about the near-field effect. Need to grab some paper and pen and convince myself. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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 12/12/2011 1:19:31 PM, Magnus Danielson (mag...@rubidium.dyndns.org) wrote: On 12/12/2011 01:37 AM, Jim Lux wrote: On 12/11/11 4:04 PM, Tom Van Baak wrote: GCPC -- gravity controlled pendulum clock (elevation) intriguing. From your parenthetical remark, I'm assuming you move the whole assembly up and down to adjust the speed? I was thinking about a huge mass that moves around? let's see.. period is proportional to sqrt(1/g) g is proportional to 1/r^2, so period is proportional to r. Earth is roughly 7000 km radius, so moving it 1 meter higher or lower changes the period by 1part in 7million... interesting. Hmm... how does the near-field gravitational pull behave? The far-field is surely r^-2, but wonder about the near-field effect. Need to grab some paper and pen and convince myself. For a spherical homogenious mass of radius R; g goes as r^+1 for rR and as r^-2 for rR. (This is a freshman undergraduate Physics problem.) Bill Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time- nuts and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing 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?
Aha, there is a near-field for gravity too? Interesting... going to google for gravitational near-field at once! On Mon, Dec 12, 2011 at 11:19 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 12/12/2011 01:37 AM, Jim Lux wrote: On 12/11/11 4:04 PM, Tom Van Baak wrote: GCPC -- gravity controlled pendulum clock (elevation) intriguing. From your parenthetical remark, I'm assuming you move the whole assembly up and down to adjust the speed? I was thinking about a huge mass that moves around? let's see.. period is proportional to sqrt(1/g) g is proportional to 1/r^2, so period is proportional to r. Earth is roughly 7000 km radius, so moving it 1 meter higher or lower changes the period by 1part in 7million... interesting. Hmm... how does the near-field gravitational pull behave? The far-field is surely r^-2, but wonder about the near-field effect. Need to grab some paper and pen and convince myself. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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?
Folks, Actually, the USGS goes around measuring the local gravitational constant in various places. There was a gravimeter set up in the basement of one of the local universities a few years back doing just that. And some time ago, the U.S. spent a fair amount of time, money and effort (presumably as did the Soviet Union and others) mapping the Earth's external gravitational field to correct for its effect on ballistic missile trajectory. Probably still do. Francis On Dec 12, 2011, at 5:19 PM, Magnus Danielson wrote: On 12/12/2011 01:37 AM, Jim Lux wrote: On 12/11/11 4:04 PM, Tom Van Baak wrote: GCPC -- gravity controlled pendulum clock (elevation) intriguing. From your parenthetical remark, I'm assuming you move the whole assembly up and down to adjust the speed? I was thinking about a huge mass that moves around? let's see.. period is proportional to sqrt(1/g) g is proportional to 1/r^2, so period is proportional to r. Earth is roughly 7000 km radius, so moving it 1 meter higher or lower changes the period by 1part in 7million... interesting. Hmm... how does the near-field gravitational pull behave? The far-field is surely r^-2, but wonder about the near-field effect. Need to grab some paper and pen and convince myself. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gravity controlled pendulumn clock?
On 12/12/11 2:19 PM, Magnus Danielson wrote: On 12/12/2011 01:37 AM, Jim Lux wrote: On 12/11/11 4:04 PM, Tom Van Baak wrote: GCPC -- gravity controlled pendulum clock (elevation) intriguing. From your parenthetical remark, I'm assuming you move the whole assembly up and down to adjust the speed? I was thinking about a huge mass that moves around? let's see.. period is proportional to sqrt(1/g) g is proportional to 1/r^2, so period is proportional to r. Earth is roughly 7000 km radius, so moving it 1 meter higher or lower changes the period by 1part in 7million... interesting. Hmm... how does the near-field gravitational pull behave? The far-field is surely r^-2, but wonder about the near-field effect. Oh.. I see.. you're thinking that approximating the field as that of a point mass when you're close to the surface of a sphere isn't valid. Hmm. this sounds like one of those integration over a volume problems I was doing 35 years ago in school. integrate (1/r^2)dm for dm over a sphere.. ___ time-nuts mailing 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 12/12/11 2:19 PM, Magnus Danielson wrote: On 12/12/2011 01:37 AM, Jim Lux wrote: On 12/11/11 4:04 PM, Tom Van Baak wrote: GCPC -- gravity controlled pendulum clock (elevation) intriguing. From your parenthetical remark, I'm assuming you move the whole assembly up and down to adjust the speed? I was thinking about a huge mass that moves around? let's see.. period is proportional to sqrt(1/g) g is proportional to 1/r^2, so period is proportional to r. Earth is roughly 7000 km radius, so moving it 1 meter higher or lower changes the period by 1part in 7million... interesting. Hmm... how does the near-field gravitational pull behave? The far-field is surely r^-2, but wonder about the near-field effect. If the mass is spherically symmetrical (which I assumed), then Gauss's law says that the gravitational force at a distance r from the center is M* G/r^2 pointing directly inward where M is the total mass within radius r. Mass beyond radius r has no net effect (like potential inside a conductive sphere, it all exactly cancels) wikipedia Shell Theorem has a nice exposition. (which I will readily confess I did not remember) As other posters have pointed out, if the mass distribution isn't spherically symmetric, then g will change. Interestingly, until there were artificial satellites, you couldn't tell that the earth is slightly pear shaped. ___ time-nuts mailing 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?
Folks, Actually, the USGS goes around measuring the local gravitational constant in various places. There was a gravimeter set up in the basement of one of the local universities a few years back doing just that. And some time ago, the U.S. spent a fair amount of time, money and effort (presumably as did the Soviet Union and others) mapping the Earth's external gravitational field to correct for its effect on ballistic missile trajectory. Probably still do. Francis Your intertial naviation systems accelerometers will always sense gravity. The INS computations will need to substract the local gravity vector before integrating acceleration to velocity and then position. This becomes very critical for high accuracy applications where GPS is either not available (submarines) or ICBMs which should work even with GPS knocked down. This is a reason to map gravity anomalies. -- Björn ___ time-nuts mailing 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?
OK, you are referring to the gravitational field just inside the mass as near field. I was thinking about something like the near EM field. On Tue, Dec 13, 2011 at 12:46 AM, b...@lysator.liu.se wrote: Folks, Actually, the USGS goes around measuring the local gravitational constant in various places. There was a gravimeter set up in the basement of one of the local universities a few years back doing just that. And some time ago, the U.S. spent a fair amount of time, money and effort (presumably as did the Soviet Union and others) mapping the Earth's external gravitational field to correct for its effect on ballistic missile trajectory. Probably still do. Francis Your intertial naviation systems accelerometers will always sense gravity. The INS computations will need to substract the local gravity vector before integrating acceleration to velocity and then position. This becomes very critical for high accuracy applications where GPS is either not available (submarines) or ICBMs which should work even with GPS knocked down. This is a reason to map gravity anomalies. -- Björn ___ time-nuts mailing 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] FE-5680A
I blame you all .. I have no reason to get one of the $40 units, but sigh .. I did. wonder how many of the 40 odd the seller had, were bought by TN's -pete ___ time-nuts mailing 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
Hi My guess is that the supply is in the thousands... Bob On Dec 12, 2011, at 7:16 PM, Pete Lancashire p...@petelancashire.com wrote: I blame you all .. I have no reason to get one of the $40 units, but sigh .. I did. wonder how many of the 40 odd the seller had, were bought by TN's -pete ___ time-nuts mailing 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
Though I have not purchased one or two and at this point they won't arrive before Christmas, I suspect that we time nuts really have not made a huge dent measured by the posts here. This is indeed one of those deals. Regards Paul. On Mon, Dec 12, 2011 at 7:22 PM, Bob Camp li...@rtty.us wrote: Hi My guess is that the supply is in the thousands... Bob On Dec 12, 2011, at 7:16 PM, Pete Lancashire p...@petelancashire.com wrote: I blame you all .. I have no reason to get one of the $40 units, but sigh .. I did. wonder how many of the 40 odd the seller had, were bought by TN's -pete ___ time-nuts mailing 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 4:22 PM, Bob Camp li...@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.
Re: [time-nuts] FE-5680A
Some of the offers include free shipping, others not. That affects the calculation. On 12/12/2011 05:42 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. -- 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 ___ time-nuts mailing 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
I had thought of doing the same .. but trying trying to keep the junk pile lower then the roof On Mon, Dec 12, 2011 at 5:42 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Mon, Dec 12, 2011 at 4:22 PM, Bob Camp li...@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. ___ time-nuts mailing 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?
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.
Re: [time-nuts] FE-5680A
Hi There are several dozen listings for the FE-5680's if you count up all the different sellers, shipping options, and PC board / no pc board choices. My *guess* is that there are also another batch of listings if you dig into the European and Asian eBay listings. That's a lot of activity ... Bob On Dec 12, 2011, at 8:42 PM, Chris Albertson wrote: On Mon, Dec 12, 2011 at 4:22 PM, Bob Camp li...@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. ___ time-nuts mailing 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?
On 12/12/2011 5:54 PM, Chris Albertson wrote: 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. The LC filter in the TADD-1 is very effective. Mind you the coil winding information given in the parts list is incorrect. 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] FE-5680A
Pete I have been trying to keep your pile down. ;-) If I do buy them it will be a pair also. Regards Paul WB8TSL On Mon, Dec 12, 2011 at 8:48 PM, Pete Lancashire p...@petelancashire.comwrote: I had thought of doing the same .. but trying trying to keep the junk pile lower then the roof On Mon, Dec 12, 2011 at 5:42 PM, Chris Albertson albertson.ch...@gmail.com wrote: On Mon, Dec 12, 2011 at 4:22 PM, Bob Camp li...@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. ___ time-nuts mailing 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?
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.
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.
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.
Re: [time-nuts] gravity controlled pendulumn clock?
Let's see, arguably the most accurate pendulum clock was the Shortt clock. It was good to 200 microseconds/day, or about 2 E-9, where you could see the effect of the moon and the sun, just. Suppose I have one of those beauties in my basement, with the requisite apparatus to compare it to a Caesium clock disciplined by GPS. Suppose my wife drives her 3000 pound car out of the garage, about 20 feet away. What will be the affect of that local change in mass? Could I discipline a Shortt clock to GPS by using a PLL that slid a one ton mass along the basement floor near the free pendulum? Sliding the one ton mass is left as an exercise for the reader, as is installing it in the basement. Yours in search of more perfect knowledge outside my field, Bill Hawkins ___ time-nuts mailing 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
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.
Re: [time-nuts] gravity controlled pendulumn clock?
Suppose I have one of those beauties in my basement, with the requisite apparatus to compare it to a Caesium clock disciplined by GPS. Suppose my wife drives her 3000 pound car out of the garage, about 20 feet away. What will be the affect of that local change in mass? Could I discipline a Shortt clock to GPS by using a PLL that slid a one ton mass along the basement floor near the free pendulum? Sliding the one ton mass is left as an exercise for the reader, as is installing it in the basement. The one ton weight in the basement could be a lot closer than 20 feet. One ton is not a big deal if you have the resources for a basement setup good enough to get the best from a Shortt clock. Iron is 491 lbs/ft^3, so that's only 2x2x1 foot for a ton. The book Tuxedo Park describes Alfred Loomis' home lab. He had 3 Shortt clocks setup in a basement cave cut into bedrock. They would get into lock step unless they were arranged in a triangle all facing the middle. I don't know if the coupling was gravity or mechanical. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gravity controlled pendulumn clock?
Instead of a GPS disciplined one ton mass, Huygens used a second clock on his mantel. The very slight acceleration that each pendulum exerted on the mantel caused the other clock to displace slightly, so its escapement triggered either earlier or later, and finally the clocks became synchronized with their pendulums 180 degrees out of phase. I'm sure a large oscillating mass anywhere near your house -- i.e. wherever a seismograph would detect it -- would do the same thing, regardless of gravity. Aart Olsen - Original Message - From: Bill Hawkins b...@iaxs.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, December 12, 2011 9:17:07 PM Subject: Re: [time-nuts] gravity controlled pendulumn clock? Could I discipline a Shortt clock to GPS by using a PLL that slid a one ton mass along the basement floor near the free pendulum? Sliding the one ton mass is left as an exercise for the reader, as is installing it in the basement. ___ time-nuts mailing 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?
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.
