to Chris What I've seen is that holding 0.1 C AT the SENSOR is pretty easy, (Lady Heather will hold the TBolt's sensor to 0.01 deg using just a fan), AND if you blow a lot of air around, then keeping the air gradients inside a closed 'oven box' below 0.1 deg is also NO problem. to Bert Have you measure what the Temperature coeff is over normal room changes with and without the addition of the temp controller? What is the best configuration to keep the fe5680 freq constant? For the LPRO, what I found by experiment worked best for me is to place the unit upside down so the heat sink was on top. If any air was blown on the non heat sink side, that would greatly effect the frequency stability in a bad way. A way to get around the compromise of where the best place is to put the sensor, either close to the heat source or close to the device. Best answer is BOTH. The way to get high end control and a much more stable control loop, is to use TWO temperature sensors. Put one temperature sensor near the Heat source and a second one at the place you want to hold constant. Then in effect 'AC couple' the heat source sensor, so that it does the course temperature control. One way to do this is to set it up so that the heat source sensor is the feed-forward or "D" input for the main sensor PID control loop. Another way to set it up is so that the device sensor's error slowly changes the temperature set-point of the heat source's temperature control loop. ws *************** >I am, as I reported previously using a SMD LM335 away from the fan and held > down with a screw and a small bracket and I get consistent .1 C. I do not >think that I would get 1 E-12 over weeks when my lab has seen more than >5C temperature changes if my temperature readings are not correct. >Do not forget this was a quick and dirty setup, the final product will look > more professional. >Bert Kehren ************* albertson.chris at gmail.com writes: On Tue, Jan 17, 2012 at 8:38 AM, <EWKehren at aol.com> wrote: >>> I am using a fan that holds it within .1 C Its been month since I >>>measured it but I did report it here and I think it is 42.7C. >>0.1C is very good for just using a fan. What is the fe5680 >>mounted to? just the heat sink or is there a thick metal plate. >>Also what are you using as a heat sensor. Is the sensor press fit to >>the heat sink or. I do remember reading about your temperature >>controlled fan but not the 0.1C part. I'd have guessed you could only >>do about 2.0C with a setup like yours. >>Chris Albertson >>Redondo Beach, California

I tried a simple bang-bang controller (LM35 temp sensor+comparator+pass transistor to drive a small fan) with the LM35 taped to the center of a large finned heatsink. The FE-5680A+heatsink are sitting upside down, so heatsink fins point up. LM35 leads wired with 34 gauge wire, which is taped along heatsink surface. The fan cycle time was about 20 seconds, and the peak variation measured at the LM35 was about 0.2 degrees. Now, of course what I am controlling is the top surface of the heatsink. What's the temperature variation inside? Well, another temperature sensor, a thermistor full bridge attached to the center top surface of the 5680A (which is underneath, in my setup) indicates that surface varies only 4 millidegrees C in the short term (one fan cycle) due to the thermal mass of the assembly. However, long term it drifts much more along with ambient, because I do not have good insulation around the body of the 5680A. I plan to put it in a well-insulated box with just the heatsink exposed, so nearly all the heat transfer happens at the heatsink fin surface, which I am controlling. I am guessing I can manage 0.01 C stability inside the box that way. -John Beale > -------Original Message------- > From: WarrenS <warrensjmail-one@yahoo.com> > To: Discussion of precise time and frequency measurement <time-nuts@febo.com> > Subject: Re: [time-nuts] 5680A update > Sent: 17 Jan '12 11:52 > > to Chris > What I've seen is that holding 0.1 C AT the SENSOR is pretty easy, > (Lady Heather will hold the TBolt's sensor to 0.01 deg using just a fan), > AND if you blow a lot of air around, then keeping the air gradients inside a > closed 'oven box' below 0.1 deg is also NO problem. > > to Bert > Have you measure what the Temperature coeff is over normal room changes with > and without the addition of the temp controller? > What is the best configuration to keep the fe5680 freq constant? > For the LPRO, what I found by experiment worked best for me is to place the > unit upside down so the heat sink was on top. > If any air was blown on the non heat sink side, that would greatly effect > the frequency stability in a bad way. > > A way to get around the compromise of where the best place is to put the > sensor, either close to the heat source or close to the device. > Best answer is BOTH. The way to get high end control and a much more stable > control loop, is to use TWO temperature sensors. > Put one temperature sensor near the Heat source and a second one at the > place you want to hold constant. > Then in effect 'AC couple' the heat source sensor, so that it does the > course temperature control. > One way to do this is to set it up so that the heat source sensor is the > feed-forward or "D" input for the main sensor PID control loop. > Another way to set it up is so that the device sensor's error slowly changes > the temperature set-point of the heat source's temperature control loop. > > ws > > *************** > >I am, as I reported previously using a SMD LM335 away from the fan and held > > down with a screw and a small bracket and I get consistent .1 C. I do not > >think that I would get 1 E-12  over weeks when my lab has seen more than > >5C temperature changes if my temperature readings are not correct. > >Do not forget this was a quick and dirty setup, the final product will look > > more professional. > >Bert Kehren > > ************* > albertson.chris at gmail.com writes: > > On Tue,  Jan 17, 2012 at 8:38 AM,  <EWKehren at aol.com> wrote: > >>> I am  using a fan that holds it within .1 C Its been month since I > >>>measured it but I did report it here and I think it is 42.7C. > > >>0.1C is very good  for just using a fan.     What is the  fe5680 > >>mounted  to?  just the heat sink or is there a thick metal plate. > >>Also what are  you using as a heat sensor.  Is the sensor press fit to > >>the heat sink  or.    I do remember reading about your temperature > >>controlled  fan but not the 0.1C part.   I'd have guessed you could only > >>do  about 2.0C with a setup like yours. > > >>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. >

Well done. You have answered a couple of questions for me. The heat sink inside is small so its easy to see why all sides of the case should be close in temperature. Like you in tinkering, I attached 4 reasonable size heat sinks with the case off and noticed I could drop the internal heat sink to 115 degrees. Granted everything cooks inside but it seems a bad way to run things. Though the xtal does need the stability. I think I may follow your lead and attach an external sink to dump extra heat from the regulators. No fan just open air. I hate fans. ;-) Regards Paul WB8TSL On Tue, Jan 17, 2012 at 3:44 PM, beale <beale@bealecorner.com> wrote: > I tried a simple bang-bang controller (LM35 temp sensor+comparator+pass > transistor to drive a small fan) with the LM35 taped to the center of a > large finned heatsink. The FE-5680A+heatsink are sitting upside down, so > heatsink fins point up. LM35 leads wired with 34 gauge wire, which is taped > along heatsink surface. The fan cycle time was about 20 seconds, and the > peak variation measured at the LM35 was about 0.2 degrees. Now, of course > what I am controlling is the top surface of the heatsink. What's the > temperature variation inside? Well, another temperature sensor, a > thermistor full bridge attached to the center top surface of the 5680A > (which is underneath, in my setup) indicates that surface varies only 4 > millidegrees C in the short term (one fan cycle) due to the thermal mass of > the assembly. However, long term it drifts much more along with ambient, > because I do not have good insulation around the body of the 5680A. I plan > to put it in a well-insulated box with just the heatsink exposed, so nearly > all the heat transfer happens at the heatsink fin surface, which I am > controlling. I am guessing I can manage 0.01 C stability inside the box > that way. > > -John Beale > > > -------Original Message------- > > From: WarrenS <warrensjmail-one@yahoo.com> > > To: Discussion of precise time and frequency measurement < > time-nuts@febo.com> > > Subject: Re: [time-nuts] 5680A update > > Sent: 17 Jan '12 11:52 > > > > to Chris > > What I've seen is that holding 0.1 C AT the SENSOR is pretty easy, > > (Lady Heather will hold the TBolt's sensor to 0.01 deg using just a > fan), > > AND if you blow a lot of air around, then keeping the air gradients > inside a > > closed 'oven box' below 0.1 deg is also NO problem. > > > > to Bert > > Have you measure what the Temperature coeff is over normal room changes > with > > and without the addition of the temp controller? > > What is the best configuration to keep the fe5680 freq constant? > > For the LPRO, what I found by experiment worked best for me is to place > the > > unit upside down so the heat sink was on top. > > If any air was blown on the non heat sink side, that would greatly > effect > > the frequency stability in a bad way. > > > > A way to get around the compromise of where the best place is to put the > > sensor, either close to the heat source or close to the device. > > Best answer is BOTH. The way to get high end control and a much more > stable > > control loop, is to use TWO temperature sensors. > > Put one temperature sensor near the Heat source and a second one at the > > place you want to hold constant. > > Then in effect 'AC couple' the heat source sensor, so that it does the > > course temperature control. > > One way to do this is to set it up so that the heat source sensor is the > > feed-forward or "D" input for the main sensor PID control loop. > > Another way to set it up is so that the device sensor's error slowly > changes > > the temperature set-point of the heat source's temperature control loop. > > > > ws > > > > *************** > > >I am, as I reported previously using a SMD LM335 away from the fan and > held > > > down with a screw and a small bracket and I get consistent .1 C. I do > not > > >think that I would get 1 E-12 over weeks when my lab has seen more > than > > >5C temperature changes if my temperature readings are not correct. > > >Do not forget this was a quick and dirty setup, the final product will > look > > > more professional. > > >Bert Kehren > > > > ************* > > albertson.chris at gmail.com writes: > > > > On Tue, Jan 17, 2012 at 8:38 AM, <EWKehren at aol.com> wrote: > > >>> I am using a fan that holds it within .1 C Its been month since I > > >>>measured it but I did report it here and I think it is 42.7C. > > > > >>0.1C is very good for just using a fan. What is the fe5680 > > >>mounted to? just the heat sink or is there a thick metal plate. > > >>Also what are you using as a heat sensor. Is the sensor press fit to > > >>the heat sink or. I do remember reading about your temperature > > >>controlled fan but not the 0.1C part. I'd have guessed you could > only > > >>do about 2.0C with a setup like yours. > > > > >>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. >

Hi Since they used a magnetic outer case I'd keep it in place. Rb's are sensitive to magnetic field. Anything that attenuates external fields is helping you out. Bob -----Original Message----- From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of paul swed Sent: Tuesday, January 17, 2012 4:02 PM To: beale; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 5680A update (temperature stabilization) Well done. You have answered a couple of questions for me. The heat sink inside is small so its easy to see why all sides of the case should be close in temperature. Like you in tinkering, I attached 4 reasonable size heat sinks with the case off and noticed I could drop the internal heat sink to 115 degrees. Granted everything cooks inside but it seems a bad way to run things. Though the xtal does need the stability. I think I may follow your lead and attach an external sink to dump extra heat from the regulators. No fan just open air. I hate fans. ;-) Regards Paul WB8TSL On Tue, Jan 17, 2012 at 3:44 PM, beale <beale@bealecorner.com> wrote: > I tried a simple bang-bang controller (LM35 temp sensor+comparator+pass > transistor to drive a small fan) with the LM35 taped to the center of a > large finned heatsink. The FE-5680A+heatsink are sitting upside down, so > heatsink fins point up. LM35 leads wired with 34 gauge wire, which is taped > along heatsink surface. The fan cycle time was about 20 seconds, and the > peak variation measured at the LM35 was about 0.2 degrees. Now, of course > what I am controlling is the top surface of the heatsink. What's the > temperature variation inside? Well, another temperature sensor, a > thermistor full bridge attached to the center top surface of the 5680A > (which is underneath, in my setup) indicates that surface varies only 4 > millidegrees C in the short term (one fan cycle) due to the thermal mass of > the assembly. However, long term it drifts much more along with ambient, > because I do not have good insulation around the body of the 5680A. I plan > to put it in a well-insulated box with just the heatsink exposed, so nearly > all the heat transfer happens at the heatsink fin surface, which I am > controlling. I am guessing I can manage 0.01 C stability inside the box > that way. > > -John Beale > > > -------Original Message------- > > From: WarrenS <warrensjmail-one@yahoo.com> > > To: Discussion of precise time and frequency measurement < > time-nuts@febo.com> > > Subject: Re: [time-nuts] 5680A update > > Sent: 17 Jan '12 11:52 > > > > to Chris > > What I've seen is that holding 0.1 C AT the SENSOR is pretty easy, > > (Lady Heather will hold the TBolt's sensor to 0.01 deg using just a > fan), > > AND if you blow a lot of air around, then keeping the air gradients > inside a > > closed 'oven box' below 0.1 deg is also NO problem. > > > > to Bert > > Have you measure what the Temperature coeff is over normal room changes > with > > and without the addition of the temp controller? > > What is the best configuration to keep the fe5680 freq constant? > > For the LPRO, what I found by experiment worked best for me is to place > the > > unit upside down so the heat sink was on top. > > If any air was blown on the non heat sink side, that would greatly > effect > > the frequency stability in a bad way. > > > > A way to get around the compromise of where the best place is to put the > > sensor, either close to the heat source or close to the device. > > Best answer is BOTH. The way to get high end control and a much more > stable > > control loop, is to use TWO temperature sensors. > > Put one temperature sensor near the Heat source and a second one at the > > place you want to hold constant. > > Then in effect 'AC couple' the heat source sensor, so that it does the > > course temperature control. > > One way to do this is to set it up so that the heat source sensor is the > > feed-forward or "D" input for the main sensor PID control loop. > > Another way to set it up is so that the device sensor's error slowly > changes > > the temperature set-point of the heat source's temperature control loop. > > > > ws > > > > *************** > > >I am, as I reported previously using a SMD LM335 away from the fan and > held > > > down with a screw and a small bracket and I get consistent .1 C. I do > not > > >think that I would get 1 E-12 over weeks when my lab has seen more > than > > >5C temperature changes if my temperature readings are not correct. > > >Do not forget this was a quick and dirty setup, the final product will > look > > > more professional. > > >Bert Kehren > > > > ************* > > albertson.chris at gmail.com writes: > > > > On Tue, Jan 17, 2012 at 8:38 AM, <EWKehren at aol.com> wrote: > > >>> I am using a fan that holds it within .1 C Its been month since I > > >>>measured it but I did report it here and I think it is 42.7C. > > > > >>0.1C is very good for just using a fan. What is the fe5680 > > >>mounted to? just the heat sink or is there a thick metal plate. > > >>Also what are you using as a heat sensor. Is the sensor press fit to > > >>the heat sink or. I do remember reading about your temperature > > >>controlled fan but not the 0.1C part. I'd have guessed you could > only > > >>do about 2.0C with a setup like yours. > > > > >>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.

Electronic Goldmine has nickel-iron magnetic shielding sheet, 6"x9" x.005" for 6 bucks p/n G18646 peel and stick at that. Don Bob Camp > Hi > > Since they used a magnetic outer case I'd keep it in place. Rb's are > sensitive to magnetic field. Anything that attenuates external fields is > helping you out. > > Bob > > -----Original Message----- > From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On > Behalf Of paul swed > Sent: Tuesday, January 17, 2012 4:02 PM > To: beale; Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] 5680A update (temperature stabilization) > > Well done. > You have answered a couple of questions for me. The heat sink inside is > small so its easy to see why all sides of the case should be close in > temperature. > Like you in tinkering, I attached 4 reasonable size heat sinks with the > case off and noticed I could drop the internal heat sink to 115 degrees. > Granted everything cooks inside but it seems a bad way to run things. > Though the xtal does need the stability. > I think I may follow your lead and attach an external sink to dump extra > heat from the regulators. No fan just open air. > I hate fans. ;-) > Regards > Paul > WB8TSL > > On Tue, Jan 17, 2012 at 3:44 PM, beale <beale@bealecorner.com> wrote: > >> I tried a simple bang-bang controller (LM35 temp >> sensor+comparator+pass >> transistor to drive a small fan) with the LM35 taped to the center of >> a >> large finned heatsink. The FE-5680A+heatsink are sitting upside down, >> so >> heatsink fins point up. LM35 leads wired with 34 gauge wire, which is > taped >> along heatsink surface. The fan cycle time was about 20 seconds, and >> the >> peak variation measured at the LM35 was about 0.2 degrees. Now, of >> course >> what I am controlling is the top surface of the heatsink. What's the >> temperature variation inside? Well, another temperature sensor, a >> thermistor full bridge attached to the center top surface of the 5680A >> (which is underneath, in my setup) indicates that surface varies only >> 4 >> millidegrees C in the short term (one fan cycle) due to the thermal >> mass > of >> the assembly. However, long term it drifts much more along with >> ambient, >> because I do not have good insulation around the body of the 5680A. I >> plan >> to put it in a well-insulated box with just the heatsink exposed, so > nearly >> all the heat transfer happens at the heatsink fin surface, which I am >> controlling. I am guessing I can manage 0.01 C stability inside the >> box >> that way. >> >> -John Beale >> >> > -------Original Message------- >> > From: WarrenS <warrensjmail-one@yahoo.com> >> > To: Discussion of precise time and frequency measurement < >> time-nuts@febo.com> >> > Subject: Re: [time-nuts] 5680A update >> > Sent: 17 Jan '12 11:52 >> > >> > to Chris >> > What I've seen is that holding 0.1 C AT the SENSOR is pretty easy, >> > (Lady Heather will hold the TBolt's sensor to 0.01 deg using just a >> fan), >> > AND if you blow a lot of air around, then keeping the air gradients >> inside a >> > closed 'oven box' below 0.1 deg is also NO problem. >> > >> > to Bert >> > Have you measure what the Temperature coeff is over normal room >> changes >> with >> > and without the addition of the temp controller? >> > What is the best configuration to keep the fe5680 freq constant? >> > For the LPRO, what I found by experiment worked best for me is to >> place >> the >> > unit upside down so the heat sink was on top. >> > If any air was blown on the non heat sink side, that would greatly >> effect >> > the frequency stability in a bad way. >> > >> > A way to get around the compromise of where the best place is to >> put > the >> > sensor, either close to the heat source or close to the device. >> > Best answer is BOTH. The way to get high end control and a much >> more >> stable >> > control loop, is to use TWO temperature sensors. >> > Put one temperature sensor near the Heat source and a second one at >> the >> > place you want to hold constant. >> > Then in effect 'AC couple' the heat source sensor, so that it does >> the >> > course temperature control. >> > One way to do this is to set it up so that the heat source sensor >> is > the >> > feed-forward or "D" input for the main sensor PID control loop. >> > Another way to set it up is so that the device sensor's error >> slowly >> changes >> > the temperature set-point of the heat source's temperature control > loop. >> > >> > ws >> > >> > *************** >> > >I am, as I reported previously using a SMD LM335 away from the fan >> and >> held >> > > down with a screw and a small bracket and I get consistent .1 C. >> I do >> not >> > >think that I would get 1 E-12 over weeks when my lab has seen >> more >> than >> > >5C temperature changes if my temperature readings are not correct. >> > >Do not forget this was a quick and dirty setup, the final product >> will >> look >> > > more professional. >> > >Bert Kehren >> > >> > ************* >> > albertson.chris at gmail.com writes: >> > >> > On Tue, Jan 17, 2012 at 8:38 AM, <EWKehren at aol.com> wrote: >> > >>> I am using a fan that holds it within .1 C Its been month >> since I >> > >>>measured it but I did report it here and I think it is 42.7C. >> > >> > >>0.1C is very good for just using a fan. What is the fe5680 >> > >>mounted to? just the heat sink or is there a thick metal plate. >> > >>Also what are you using as a heat sensor. Is the sensor press >> fit > to >> > >>the heat sink or. I do remember reading about your >> temperature >> > >>controlled fan but not the 0.1C part. I'd have guessed you >> could >> only >> > >>do about 2.0C with a setup like yours. >> > >> > >>Chris Albertson >> > >>Redondo Beach, California >> > >> > >> > _______________________________________________ >> > time-nuts mailing list -- time-nuts@febo.com >> > To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> > >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- "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