Re: [time-nuts] FE-5680 frequency jump
On Fri, 5 Apr 2013 23:18:49 -0600 (MDT) Don Latham d...@montana.com wrote: Actually, mumetal easily loses permeability, hence shielding ability, by mechanical stress or heat. Some mumetals are made to bend for boxes and the like, sheets available from electronics goldmine, I think. Actually, one of the questions i had in my head when waking up this morning was: Mumetal is pretty sensitive to everything.. but how is it machined if bending and heating damage it? Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing 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-5680 frequency jump
Attila Kinali wrote: On Fri, 5 Apr 2013 23:18:49 -0600 (MDT) Don Lathamd...@montana.com wrote: Actually, mumetal easily loses permeability, hence shielding ability, by mechanical stress or heat. Some mumetals are made to bend for boxes and the like, sheets available from electronics goldmine, I think. Actually, one of the questions i had in my head when waking up this morning was: Mumetal is pretty sensitive to everything.. but how is it machined if bending and heating damage it? Attila Kinali By annealing it afterwards in a hydrogen atmosphere at around 400C. Bruce ___ time-nuts mailing 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-5680 frequency jump
On 04/06/2013 02:22 AM, EB4APL wrote: Thank you for the info, I used to attach a magnetic mount surface thermometer to my FRS-C to check its operating temperature after installing it in a box. I think it is time to power it up and after some days check it against the GPS. Ehm. Rubidiums is tweaked by magnetic field adjustments, and you have my-metal shields to shield of ambient fields as they go in the wrong direction typically, change, etc. Use the C-field EFC input and not magnets to tweak it... Please keep magnets away! Cheers, Magnus Regards, Ignacio EB4APL On 05/04/2013 20:59, Bob Quenelle wrote: I found the cause of the 4 mHz frequency jump. I have an LPRO-101, an FE-5680, power supplies and a Motorola M12T GPS board in a surplus case. When I put the case away to work on another project I piled the hockey puck antenna and lead in the case and it happened to land on the FE-5680. I noticed the antenna stuck firmly to the FE-5680 case when I got the project back out. I found I could get a 6 mHz (0.6 ppb) shift comparing the frequency with residual magnetism from the magnet stuck on the FE-5680 case to the frequency after demagnetizing the FE-5680 case. Unintentional C field adjustment. Dope slap, live and learn. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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-5680 frequency jump
On 04/06/2013 09:34 AM, Attila Kinali wrote: On Fri, 5 Apr 2013 23:18:49 -0600 (MDT) Don Lathamd...@montana.com wrote: Actually, mumetal easily loses permeability, hence shielding ability, by mechanical stress or heat. Some mumetals are made to bend for boxes and the like, sheets available from electronics goldmine, I think. Actually, one of the questions i had in my head when waking up this morning was: Mumetal is pretty sensitive to everything.. but how is it machined if bending and heating damage it? As mentioned on this list, you re-anneal it again. Bruce has more details. http://en.wikipedia.org/wiki/Mu-metal http://www.magnetic-shield.com/pdf/mu-2.pdf 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] FE-5680 frequency jump
On 04/06/2013 10:06 AM, Bruce Griffiths wrote: Attila Kinali wrote: On Fri, 5 Apr 2013 23:18:49 -0600 (MDT) Don Lathamd...@montana.com wrote: Actually, mumetal easily loses permeability, hence shielding ability, by mechanical stress or heat. Some mumetals are made to bend for boxes and the like, sheets available from electronics goldmine, I think. Actually, one of the questions i had in my head when waking up this morning was: Mumetal is pretty sensitive to everything.. but how is it machined if bending and heating damage it? Attila Kinali By annealing it afterwards in a hydrogen atmosphere at around 400C. The link I just tossed in another message says 1121C. 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] FE-5680 frequency jump
On 04/06/2013 01:21 PM, Magnus Danielson wrote: On 04/06/2013 09:34 AM, Attila Kinali wrote: On Fri, 5 Apr 2013 23:18:49 -0600 (MDT) Don Lathamd...@montana.com wrote: Actually, mumetal easily loses permeability, hence shielding ability, by mechanical stress or heat. Some mumetals are made to bend for boxes and the like, sheets available from electronics goldmine, I think. Actually, one of the questions i had in my head when waking up this morning was: Mumetal is pretty sensitive to everything.. but how is it machined if bending and heating damage it? As mentioned on this list, you re-anneal it again. Bruce has more details. http://en.wikipedia.org/wiki/Mu-metal http://www.magnetic-shield.com/pdf/mu-2.pdf These links could be of further use: http://www.magnetic-shield.com/science-research-and-education.html http://www.magnetic-shield.com/faqs-all-about-shielding.html 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] FE-5680 frequency jump
Any TimeNutter worth his/her salt can do that..right! Lester B Veenstra MØYCM K1YCM W8YCM les...@veenstras.com -Original Message- By annealing it afterwards in a hydrogen atmosphere at around 400C. Bruce ___ time-nuts mailing 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-5680 frequency jump
On 4/6/13 6:08 AM, Lester Veenstra wrote: Any TimeNutter worth his/her salt can do that..right! $100 Presto 23 qt canning style pressure cooker, electric heating elements, thermocouple probes, some fiberglass insulation to reduce conductive losses. Do it in your backyard and have a straw broom handy to detect hydrogen fires. Be careful.. 400C is getting close to 660C aluminum melting point. I'm also not sure the gasket in the pressure cooker can take that temperature.. you might want to replace it with something else. Here's the reaction vessel: http://www.target.com/p/presto-23-quart-aluminum-pressure-cooker-canner/-/A-660065#prodSlot=medium_1_5 Now, if it's the 1000C+ that Magnus mentioned, that's a bit trickier.. Probably need a ceramic container. ___ time-nuts mailing 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-5680 frequency jump
Hi On Apr 6, 2013, at 9:39 AM, Jim Lux jim...@earthlink.net wrote: On 4/6/13 6:08 AM, Lester Veenstra wrote: Any TimeNutter worth his/her salt can do that..right! $100 Presto 23 qt canning style pressure cooker, electric heating elements, thermocouple probes, some fiberglass insulation to reduce conductive losses. Do it in your backyard and have a straw broom handy to detect hydrogen fires. Be careful.. 400C is getting close to 660C aluminum melting point. I'm also not sure the gasket in the pressure cooker can take that temperature.. you might want to replace it with something else. Here's the reaction vessel: http://www.target.com/p/presto-23-quart-aluminum-pressure-cooker-canner/-/A-660065#prodSlot=medium_1_5 Now, if it's the 1000C+ that Magnus mentioned, that's a bit trickier.. Probably need a ceramic container. Gee, another use for the Big Green Egg…. I wonder how BBQ grease impacts the annealing process :) I don't think I would want 1000+ C hydrogen running around in a lash up system. There are just to many ways for things to go wrong. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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-5680 frequency jump
On 4/6/13 6:55 AM, Bob Camp wrote: Hi On Apr 6, 2013, at 9:39 AM, Jim Lux jim...@earthlink.net wrote: On 4/6/13 6:08 AM, Lester Veenstra wrote: Any TimeNutter worth his/her salt can do that..right! $100 Presto 23 qt canning style pressure cooker, electric heating elements, thermocouple probes, some fiberglass insulation to reduce conductive losses. Do it in your backyard and have a straw broom handy to detect hydrogen fires. Be careful.. 400C is getting close to 660C aluminum melting point. I'm also not sure the gasket in the pressure cooker can take that temperature.. you might want to replace it with something else. Here's the reaction vessel: http://www.target.com/p/presto-23-quart-aluminum-pressure-cooker-canner/-/A-660065#prodSlot=medium_1_5 Now, if it's the 1000C+ that Magnus mentioned, that's a bit trickier.. Probably need a ceramic container. Gee, another use for the Big Green Egg…. I wonder how BBQ grease impacts the annealing process :) I suggest heading on down to the garden store for some clay pots.. I don't think I would want 1000+ C hydrogen running around in a lash up system. There are just to many ways for things to go wrong. John Strong's book has a picture of how to do it.. Shows small flames (invisible, of course) coming from the lid of the ceramic crucible wrapped in resistance wire and immersed in some sort of refractory sand. I've seen hydrogen brazing being done at a TWT manufacturing plant, and it's pretty low tech. One could definitely do it in your backyard, maybe even your apartment balcony. I don't know that I'd be generating the hydrogen by using aluminum foil in pool acid, but that's more out of laziness than anything else: getting a tank from the local gas supplier is pretty easy. The pressure of the H2 is basically slightly over atmospheric. Heated to 1000C, it's going to ignite where it leaks out, which is good, so you don't have a problem with hydrogen accumulation (and even that isn't an issue in the backyard) Since the flames are invisible, that's why you need that broom. (or the fancy IR viewing goggles, I suppose) ___ time-nuts mailing 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-5680 frequency jump
On 04/06/2013 04:23 PM, Jim Lux wrote: On 4/6/13 6:55 AM, Bob Camp wrote: Hi On Apr 6, 2013, at 9:39 AM, Jim Lux jim...@earthlink.net wrote: On 4/6/13 6:08 AM, Lester Veenstra wrote: Any TimeNutter worth his/her salt can do that..right! $100 Presto 23 qt canning style pressure cooker, electric heating elements, thermocouple probes, some fiberglass insulation to reduce conductive losses. Do it in your backyard and have a straw broom handy to detect hydrogen fires. Be careful.. 400C is getting close to 660C aluminum melting point. I'm also not sure the gasket in the pressure cooker can take that temperature.. you might want to replace it with something else. Here's the reaction vessel: http://www.target.com/p/presto-23-quart-aluminum-pressure-cooker-canner/-/A-660065#prodSlot=medium_1_5 Now, if it's the 1000C+ that Magnus mentioned, that's a bit trickier.. Probably need a ceramic container. Gee, another use for the Big Green Egg…. I wonder how BBQ grease impacts the annealing process :) I suggest heading on down to the garden store for some clay pots.. I don't think I would want 1000+ C hydrogen running around in a lash up system. There are just to many ways for things to go wrong. John Strong's book has a picture of how to do it.. Shows small flames (invisible, of course) coming from the lid of the ceramic crucible wrapped in resistance wire and immersed in some sort of refractory sand. I've seen hydrogen brazing being done at a TWT manufacturing plant, and it's pretty low tech. One could definitely do it in your backyard, maybe even your apartment balcony. I don't know that I'd be generating the hydrogen by using aluminum foil in pool acid, but that's more out of laziness than anything else: getting a tank from the local gas supplier is pretty easy. The pressure of the H2 is basically slightly over atmospheric. Heated to 1000C, it's going to ignite where it leaks out, which is good, so you don't have a problem with hydrogen accumulation (and even that isn't an issue in the backyard) Since the flames are invisible, that's why you need that broom. (or the fancy IR viewing goggles, I suppose) Back in the 80thies I skipped school to go to the university and play in their lab I made high-temperature semiconductors. We had to do essentially the same thing, but our target temperature was 950 degrees and it was oxygene environment. The over was essentially a ceramic tube with heating wires... just a large power resistor. Very low-tech. It's really the hydrogen environment which makes it a bit tricky, but having a continuous flow of hydrogen and just some minor blocking, and a pilot flame to burn of the leaking hydrogen if it has not been burned of should suffice. I think the main issue will be sourcing the right oven components, but just setting once's mine correctly they should be attainable. The power-bill is the issue. 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] FE-5680 frequency jump
On 04/06/2013 08:39 AM, Jim Lux wrote: On 4/6/13 6:08 AM, Lester Veenstra wrote: Any TimeNutter worth his/her salt can do that..right! $100 Presto 23 qt canning style pressure cooker, electric heating elements, thermocouple probes, some fiberglass insulation to reduce conductive losses. Do it in your backyard and have a straw broom handy to detect hydrogen fires. Be careful.. 400C is getting close to 660C aluminum melting point. I'm also not sure the gasket in the pressure cooker can take that temperature.. you might want to replace it with something else. Here's the reaction vessel: http://www.target.com/p/presto-23-quart-aluminum-pressure-cooker-canner/-/A-660065#prodSlot=medium_1_5 Now, if it's the 1000C+ that Magnus mentioned, that's a bit trickier.. Probably need a ceramic container. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. I had use for a kiln recently - found a very reasonable priced one at Vulcan Kilns: http://vulcankilns.com/ I got the JK-1 - 2250F (1232C) max temp. Easy to use benchtop unit. I added an inexpensive thermocouple controller unit to improve the temperature control. Has been very useful in annealing some metal springs for a project. I have no relationship with Vulcan other than being a satisfied customer. -- = Bob Smither, PhD Circuit Concepts, Inc. Every election is a sort of advance auction sale of stolen goods. -- Libertarian H.L. Mencken smit...@c-c-i.comhttp://www.C-C-I.Com281-331-2744 = attachment: smither.vcf___ time-nuts mailing 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-5680 frequency jump
I found the cause of the 4 mHz frequency jump. I have an LPRO-101, an FE-5680, power supplies and a Motorola M12T GPS board in a surplus case. When I put the case away to work on another project I piled the hockey puck antenna and lead in the case and it happened to land on the FE-5680. I noticed the antenna stuck firmly to the FE-5680 case when I got the project back out. I found I could get a 6 mHz (0.6 ppb) shift comparing the frequency with residual magnetism from the magnet stuck on the FE-5680 case to the frequency after demagnetizing the FE-5680 case. Unintentional C field adjustment. Dope slap, live and learn. Bob -Original Message- From: Magnus Danielson Sent: Monday, April 01, 2013 5:13 PM To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680 frequency jump On 04/02/2013 01:12 AM, Attila Kinali wrote: On Mon, 01 Apr 2013 23:57:48 +0200 Magnus Danielsonmag...@rubidium.dyndns.org wrote: On 04/01/2013 10:06 PM, Bob Quenelle wrote: I’ve been running an FE-5680 for maybe a total of 50 hours over the last several months. I found that an offset setting of 180 made it track GPS and (previously-set) LPRO-101 10 MHz signals. Even with power cycling, after about 1/2 hour, with an offset setting of 180 the FE-5680 was stable. The last time I turned on the FE-5680, it drifted with a setting of 180 and needed a new setting of –415 to track the other signals. That’s a change of 595 counts and with a resolution of 6.8 uHz per count, a frequency change of 4 mHz (0.004 Hz) and 0.4 ppb. Operation at the new setting is stable for now. The lock signal indicates lock and the power supply voltage is still 15V. I haven’t checked lamp voltage or VCXO voltage as that requires opening the case. How long have it been turned on since last power-up? Let it sit for a day at least. I've found that it is easy to be in too much hurry to judge the situation and trim things efter power-up. The crystal oscillator just doesn't get the time to settle in. That might be indeed the case. Figure 3 in [1] gives quite high frequency aging differences after switch on and long run time. Attila Kinali [1] http://www.pi5.uni-stuttgart.de/common/show_file.php/lectures/100/blaetter/The%20Rubidium%20Clock%20and%20Basic%20Research.pdf You are confusing the VCXOs frequency drift with that of the rubidiums (which is the result of the FLL locking of the VCXO to the rubidium resonance). If the VCXO still has a fair distance to drift, then false locking can occur while compating the initially quite vigorous drift rate. The only real way to handle that is to sit and wait for it to settle down. Only after that may trimming of the oscillator be done to zeroize the integrator state. A small commercial rubidium doesn't need very long to get a feel if it is in good condition or not, but sitting on your hands and let it warm up gives you a fair idea of just how skewed situation it is. That's also true for caesium clocks. So, sit on your hands and let it settle. Better yet, leave on while you do other things. Just recall to put enought cooling on it! 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] FE-5680 frequency jump
Thank you for this information, Bob! I have to reconsider the frequency jumps of my GPSDOs... Volker Am 05.04.2013 20:59, schrieb Bob Quenelle: I found the cause of the 4 mHz frequency jump. I have an LPRO-101, an FE-5680, power supplies and a Motorola M12T GPS board in a surplus case. When I put the case away to work on another project I piled the hockey puck antenna and lead in the case and it happened to land on the FE-5680. I noticed the antenna stuck firmly to the FE-5680 case when I got the project back out. I found I could get a 6 mHz (0.6 ppb) shift comparing the frequency with residual magnetism from the magnet stuck on the FE-5680 case to the frequency after demagnetizing the FE-5680 case. Unintentional C field adjustment. Dope slap, live and learn. Bob -Original Message- From: Magnus Danielson Sent: Monday, April 01, 2013 5:13 PM To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680 frequency jump On 04/02/2013 01:12 AM, Attila Kinali wrote: On Mon, 01 Apr 2013 23:57:48 +0200 Magnus Danielsonmag...@rubidium.dyndns.org wrote: On 04/01/2013 10:06 PM, Bob Quenelle wrote: I’ve been running an FE-5680 for maybe a total of 50 hours over the last several months. I found that an offset setting of 180 made it track GPS and (previously-set) LPRO-101 10 MHz signals. Even with power cycling, after about 1/2 hour, with an offset setting of 180 the FE-5680 was stable. The last time I turned on the FE-5680, it drifted with a setting of 180 and needed a new setting of –415 to track the other signals. That’s a change of 595 counts and with a resolution of 6.8 uHz per count, a frequency change of 4 mHz (0.004 Hz) and 0.4 ppb. Operation at the new setting is stable for now. The lock signal indicates lock and the power supply voltage is still 15V. I haven’t checked lamp voltage or VCXO voltage as that requires opening the case. How long have it been turned on since last power-up? Let it sit for a day at least. I've found that it is easy to be in too much hurry to judge the situation and trim things efter power-up. The crystal oscillator just doesn't get the time to settle in. That might be indeed the case. Figure 3 in [1] gives quite high frequency aging differences after switch on and long run time. Attila Kinali [1] http://www.pi5.uni-stuttgart.de/common/show_file.php/lectures/100/blaetter/The%20Rubidium%20Clock%20and%20Basic%20Research.pdf You are confusing the VCXOs frequency drift with that of the rubidiums (which is the result of the FLL locking of the VCXO to the rubidium resonance). If the VCXO still has a fair distance to drift, then false locking can occur while compating the initially quite vigorous drift rate. The only real way to handle that is to sit and wait for it to settle down. Only after that may trimming of the oscillator be done to zeroize the integrator state. A small commercial rubidium doesn't need very long to get a feel if it is in good condition or not, but sitting on your hands and let it warm up gives you a fair idea of just how skewed situation it is. That's also true for caesium clocks. So, sit on your hands and let it settle. Better yet, leave on while you do other things. Just recall to put enought cooling on it! 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. ___ time-nuts mailing 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-5680 frequency jump
Thank you for the info, I used to attach a magnetic mount surface thermometer to my FRS-C to check its operating temperature after installing it in a box. I think it is time to power it up and after some days check it against the GPS. Regards, Ignacio EB4APL On 05/04/2013 20:59, Bob Quenelle wrote: I found the cause of the 4 mHz frequency jump. I have an LPRO-101, an FE-5680, power supplies and a Motorola M12T GPS board in a surplus case. When I put the case away to work on another project I piled the hockey puck antenna and lead in the case and it happened to land on the FE-5680. I noticed the antenna stuck firmly to the FE-5680 case when I got the project back out. I found I could get a 6 mHz (0.6 ppb) shift comparing the frequency with residual magnetism from the magnet stuck on the FE-5680 case to the frequency after demagnetizing the FE-5680 case. Unintentional C field adjustment. Dope slap, live and learn. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680 frequency jump
There's something in the back of my mind that MuMetal is easily magnetized. If that's true, and if the FRS-C and/or FE-5680 cases are made of MuMetal (seems like a good chance), they should be demagnetized anytime they come in contact with a magnet. Ed On 4/5/2013 6:22 PM, EB4APL wrote: Thank you for the info, I used to attach a magnetic mount surface thermometer to my FRS-C to check its operating temperature after installing it in a box. I think it is time to power it up and after some days check it against the GPS. Regards, Ignacio EB4APL On 05/04/2013 20:59, Bob Quenelle wrote: I found the cause of the 4 mHz frequency jump. I have an LPRO-101, an FE-5680, power supplies and a Motorola M12T GPS board in a surplus case. When I put the case away to work on another project I piled the hockey puck antenna and lead in the case and it happened to land on the FE-5680. I noticed the antenna stuck firmly to the FE-5680 case when I got the project back out. I found I could get a 6 mHz (0.6 ppb) shift comparing the frequency with residual magnetism from the magnet stuck on the FE-5680 case to the frequency after demagnetizing the FE-5680 case. Unintentional C field adjustment. Dope slap, live and learn. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680 frequency jump
Actually, mumetal easily loses permeability, hence shielding ability, by mechanical stress or heat. Some mumetals are made to bend for boxes and the like, sheets available from electronics goldmine, I think. Ed Palmer There's something in the back of my mind that MuMetal is easily magnetized. If that's true, and if the FRS-C and/or FE-5680 cases are made of MuMetal (seems like a good chance), they should be demagnetized anytime they come in contact with a magnet. Ed On 4/5/2013 6:22 PM, EB4APL wrote: Thank you for the info, I used to attach a magnetic mount surface thermometer to my FRS-C to check its operating temperature after installing it in a box. I think it is time to power it up and after some days check it against the GPS. Regards, Ignacio EB4APL On 05/04/2013 20:59, Bob Quenelle wrote: I found the cause of the 4 mHz frequency jump. I have an LPRO-101, an FE-5680, power supplies and a Motorola M12T GPS board in a surplus case. When I put the case away to work on another project I piled the hockey puck antenna and lead in the case and it happened to land on the FE-5680. I noticed the antenna stuck firmly to the FE-5680 case when I got the project back out. I found I could get a 6 mHz (0.6 ppb) shift comparing the frequency with residual magnetism from the magnet stuck on the FE-5680 case to the frequency after demagnetizing the FE-5680 case. Unintentional C field adjustment. Dope slap, live and learn. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. De Erroribus Medicorum, R. Bacon, 13th century. If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] FE-5680 frequency jump
I’ve been running an FE-5680 for maybe a total of 50 hours over the last several months. I found that an offset setting of 180 made it track GPS and (previously-set) LPRO-101 10 MHz signals. Even with power cycling, after about 1/2 hour, with an offset setting of 180 the FE-5680 was stable. The last time I turned on the FE-5680, it drifted with a setting of 180 and needed a new setting of –415 to track the other signals. That’s a change of 595 counts and with a resolution of 6.8 uHz per count, a frequency change of 4 mHz (0.004 Hz) and 0.4 ppb. Operation at the new setting is stable for now. The lock signal indicates lock and the power supply voltage is still 15V. I haven’t checked lamp voltage or VCXO voltage as that requires opening the case. Before I start poking around, thought I’d ask if anyone has seen a similar symptom. Time to open it up? Thanks, Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680 frequency jump
Hi Bob, On 04/01/2013 10:06 PM, Bob Quenelle wrote: I’ve been running an FE-5680 for maybe a total of 50 hours over the last several months. I found that an offset setting of 180 made it track GPS and (previously-set) LPRO-101 10 MHz signals. Even with power cycling, after about 1/2 hour, with an offset setting of 180 the FE-5680 was stable. The last time I turned on the FE-5680, it drifted with a setting of 180 and needed a new setting of –415 to track the other signals. That’s a change of 595 counts and with a resolution of 6.8 uHz per count, a frequency change of 4 mHz (0.004 Hz) and 0.4 ppb. Operation at the new setting is stable for now. The lock signal indicates lock and the power supply voltage is still 15V. I haven’t checked lamp voltage or VCXO voltage as that requires opening the case. Before I start poking around, thought I’d ask if anyone has seen a similar symptom. Time to open it up? How long have it been turned on since last power-up? Let it sit for a day at least. I've found that it is easy to be in too much hurry to judge the situation and trim things efter power-up. The crystal oscillator just doesn't get the time to settle in. When triming up caesiums, I did this mistake myself, altered my ways and got a much better result. 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] FE-5680 frequency jump
On Mon, 01 Apr 2013 23:57:48 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: On 04/01/2013 10:06 PM, Bob Quenelle wrote: I’ve been running an FE-5680 for maybe a total of 50 hours over the last several months. I found that an offset setting of 180 made it track GPS and (previously-set) LPRO-101 10 MHz signals. Even with power cycling, after about 1/2 hour, with an offset setting of 180 the FE-5680 was stable. The last time I turned on the FE-5680, it drifted with a setting of 180 and needed a new setting of –415 to track the other signals. That’s a change of 595 counts and with a resolution of 6.8 uHz per count, a frequency change of 4 mHz (0.004 Hz) and 0.4 ppb. Operation at the new setting is stable for now. The lock signal indicates lock and the power supply voltage is still 15V. I haven’t checked lamp voltage or VCXO voltage as that requires opening the case. How long have it been turned on since last power-up? Let it sit for a day at least. I've found that it is easy to be in too much hurry to judge the situation and trim things efter power-up. The crystal oscillator just doesn't get the time to settle in. That might be indeed the case. Figure 3 in [1] gives quite high frequency aging differences after switch on and long run time. Attila Kinali [1] http://www.pi5.uni-stuttgart.de/common/show_file.php/lectures/100/blaetter/The%20Rubidium%20Clock%20and%20Basic%20Research.pdf -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing 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-5680 frequency jump
On 04/02/2013 01:12 AM, Attila Kinali wrote: On Mon, 01 Apr 2013 23:57:48 +0200 Magnus Danielsonmag...@rubidium.dyndns.org wrote: On 04/01/2013 10:06 PM, Bob Quenelle wrote: I’ve been running an FE-5680 for maybe a total of 50 hours over the last several months. I found that an offset setting of 180 made it track GPS and (previously-set) LPRO-101 10 MHz signals. Even with power cycling, after about 1/2 hour, with an offset setting of 180 the FE-5680 was stable. The last time I turned on the FE-5680, it drifted with a setting of 180 and needed a new setting of –415 to track the other signals. That’s a change of 595 counts and with a resolution of 6.8 uHz per count, a frequency change of 4 mHz (0.004 Hz) and 0.4 ppb. Operation at the new setting is stable for now. The lock signal indicates lock and the power supply voltage is still 15V. I haven’t checked lamp voltage or VCXO voltage as that requires opening the case. How long have it been turned on since last power-up? Let it sit for a day at least. I've found that it is easy to be in too much hurry to judge the situation and trim things efter power-up. The crystal oscillator just doesn't get the time to settle in. That might be indeed the case. Figure 3 in [1] gives quite high frequency aging differences after switch on and long run time. Attila Kinali [1] http://www.pi5.uni-stuttgart.de/common/show_file.php/lectures/100/blaetter/The%20Rubidium%20Clock%20and%20Basic%20Research.pdf You are confusing the VCXOs frequency drift with that of the rubidiums (which is the result of the FLL locking of the VCXO to the rubidium resonance). If the VCXO still has a fair distance to drift, then false locking can occur while compating the initially quite vigorous drift rate. The only real way to handle that is to sit and wait for it to settle down. Only after that may trimming of the oscillator be done to zeroize the integrator state. A small commercial rubidium doesn't need very long to get a feel if it is in good condition or not, but sitting on your hands and let it warm up gives you a fair idea of just how skewed situation it is. That's also true for caesium clocks. So, sit on your hands and let it settle. Better yet, leave on while you do other things. Just recall to put enought cooling on it! 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.
