Re: [time-nuts] FE-5680A thermal management
For reference, Ridge Equipment has a photo of one of this year's crop of FE-5680A mounted to a large aluminum plate. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=330233071735 http://i43.tinypic.com/126cpcp.jpg Leigh/WA5ZNU Almost all rubidium standards DO specify the use of some form of a heat sink. For the FRK and M100 units this can be a heat sink with around 1 fins or just bolted to a metal plate or chassis. The military freq standard that had M100's in them had the unit mounted to a 5x5x.2 aluminum plate that was in turn bolted to the chassis. My Efratom PTB-100 time bases for the Tektronix TM500 mainframes have a large heat sink mounted to a FRK style oscillator. LPROs are supposed to be mounted to a metal chassis (they usually come with a thermal pad attached to them). I have seen them lose lock in free air. I saw one mounted in a piece of cell phone equipment. It was bolted to a large heat sink that formed most of the front of the enclosure. I have also seen FE-5680A's in their native habitat (again, cell phone equipment). They were mounted to a thick (1/8?) PCB around 6x16. The side of the PCB that the 5680 was bolted to had a solid ground plane. The 5650A's had one side bolted to a metal chassis. _ Hotmail® has ever-growing storage! Don’t worry about storage limits. http://windowslive.com/Tutorial/Hotmail/Storage?ocid=TXT_TAGLM_WL_HM_Tutorial_Storage_062009 ___ 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 thermal management
le...@wa5znu.org said: For reference, Ridge Equipment has a photo of one of this year's crop of FE-5680A mounted to a large aluminum plate. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=330233071735 http://i43.tinypic.com/126cpcp.jpg Is that an aluminum plate or the top side of a PCB used as a heat sink? To me, the first picture looks green/FR4 around the edges. (and a stripe on the left) -- 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] FE-5680A thermal management
Hal Murray wrote: le...@wa5znu.org said: For reference, Ridge Equipment has a photo of one of this year's crop of FE-5680A mounted to a large aluminum plate. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=330233071735 http://i43.tinypic.com/126cpcp.jpg Is that an aluminum plate or the top side of a PCB used as a heat sink? To me, the first picture looks green/FR4 around the edges. (and a stripe on the left) Yes, that is a portion of the board I described in an earlier message. The board is thick fiberglass plated heavily on both the top and bottom. The board in the picture has been cut both above and below the 5680A. The plating ended about where the lower cut is, but the plating continued farther above the top of the unit in the picture. My earlier message gave the dimensions. One minor note about this board. The screws holding the 5680 to the borad were an unusual type. I can't remember, I think they may have been a square drive. They were difficult to remove as I had no proper tool to unscrew them. I think I made something from steel rod to start them losening. ___ 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 thermal management
They look like Torx Screws. Not so? Thanks, Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rex Sent: Monday, June 15, 2009 2:33 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE-5680A thermal management Hal Murray wrote: le...@wa5znu.org said: For reference, Ridge Equipment has a photo of one of this year's crop of FE-5680A mounted to a large aluminum plate. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=330233071735 http://i43.tinypic.com/126cpcp.jpg Is that an aluminum plate or the top side of a PCB used as a heat sink? To me, the first picture looks green/FR4 around the edges. (and a stripe on the left) Yes, that is a portion of the board I described in an earlier message. The board is thick fiberglass plated heavily on both the top and bottom. The board in the picture has been cut both above and below the 5680A. The plating ended about where the lower cut is, but the plating continued farther above the top of the unit in the picture. My earlier message gave the dimensions. One minor note about this board. The screws holding the 5680 to the borad were an unusual type. I can't remember, I think they may have been a square drive. They were difficult to remove as I had no proper tool to unscrew them. I think I made something from steel rod to start them losening. ___ 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 thermal management
No. I have one and it's very appropriate for a piece of Time-Nut equipment. They're Allen screws. :-) Ed J. L. Trantham wrote: They look like Torx Screws. Not so? Thanks, Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rex Sent: Monday, June 15, 2009 2:33 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE-5680A thermal management Hal Murray wrote: le...@wa5znu.org said: For reference, Ridge Equipment has a photo of one of this year's crop of FE-5680A mounted to a large aluminum plate. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=330233071735 http://i43.tinypic.com/126cpcp.jpg Is that an aluminum plate or the top side of a PCB used as a heat sink? To me, the first picture looks green/FR4 around the edges. (and a stripe on the left) Yes, that is a portion of the board I described in an earlier message. The board is thick fiberglass plated heavily on both the top and bottom. The board in the picture has been cut both above and below the 5680A. The plating ended about where the lower cut is, but the plating continued farther above the top of the unit in the picture. My earlier message gave the dimensions. One minor note about this board. The screws holding the 5680 to the borad were an unusual type. I can't remember, I think they may have been a square drive. They were difficult to remove as I had no proper tool to unscrew them. I think I made something from steel rod to start them losening. ___ 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 thermal management
Nevermind. I went back and looked again. The screws are a bit odd and sloppy tolerences, but a 1/16 inch allen wrench seems to work. I guess my memory from a couple years back was a bit off. -Rex Ed Palmer wrote: No. I have one and it's very appropriate for a piece of Time-Nut equipment. They're Allen screws. :-) Ed J. L. Trantham wrote: They look like Torx Screws. Not so? Thanks, Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rex Sent: Monday, June 15, 2009 2:33 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE-5680A thermal management Hal Murray wrote: le...@wa5znu.org said: For reference, Ridge Equipment has a photo of one of this year's crop of FE-5680A mounted to a large aluminum plate. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=330233071735 http://i43.tinypic.com/126cpcp.jpg Is that an aluminum plate or the top side of a PCB used as a heat sink? To me, the first picture looks green/FR4 around the edges. (and a stripe on the left) Yes, that is a portion of the board I described in an earlier message. The board is thick fiberglass plated heavily on both the top and bottom. The board in the picture has been cut both above and below the 5680A. The plating ended about where the lower cut is, but the plating continued farther above the top of the unit in the picture. My earlier message gave the dimensions. One minor note about this board. The screws holding the 5680 to the borad were an unusual type. I can't remember, I think they may have been a square drive. They were difficult to remove as I had no proper tool to unscrew them. I think I made something from steel rod to start them losening. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680A thermal management
In article 2ed501c9e87a$a7a4a850$7900a...@athlon1200, Dave Brown tract...@ihug.co.nz writes Murray et al, The package of both units is clearly meant to be mounted on something-the real question is how much heat sinking would that something have provided? Changing the external heatsinking to achieve the nominal supply current at the nominal supply voltage would appear to be the only simple way to operate the units as intended. I've not gone through this exercise yet with the 5650, but I suspect the amount of heatsinking used is not that critical. Using a variable speed fan to determine the 'correct' mounting plate temperature (corresponding to nominal supply current/voltage) might be a good way to start. The design of a heatsink to achieve the same base plate temperature should be a trivial exercise. Constraining the 'ambient' air temperature to an appropriate range in the vicinity of the unit should certainly help as well. Guys, As a datum point, I have an FE5650A mounted in a 2U 19 inch chassis. This chassis is a Tait T800 reference frequency generator, for use as a controller in quasi-synchronous wide-area mobile radio systems. That chassis has the FE-5650A mounted on an extra block of aluminium, with some finning attached if memory serves, and fitted inside the chassis. There is no internal airflow over the mounting plate, and no external fins on the case. I have the manual for this unit, and Tait make no mention of any special thermal requirements. This suggests that, beyond mounting the Rb on sufficient metal, the exact requirements are non-critical. I'll get the unit out of store and take photos/measurements if required. -- Geoff Powell ___ 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 thermal management
Leigh, I agree with Chuck. I have both an FE-5650A and an FE-5680A. With the former I was concerned about the heat, and so ran it only for short periods, until I understood what was going on. I had the impression from the data sheet that there were different heatsink options for different temperature ranges, and I now believe this led me astray. With the FE-5680A I had the opportunity to study things in more detail. There is no temperature range specification that I could find, and no particular advice in the manual regarding installation. I ran the unit from regulated 15V DC, and monitored the supply current. With no extra cooling, the steady state current was about 700mA. With air blown over it, the current increased. With the unit placed in a poly bag, the current decreased to about 650mA. By the way, the current also decreased when operated from 17V DC. This tells me that the whole structure is part of the thermal package, and we should not attempt to force down the case temperature just because the unit runs hot. My experience with high performance OCXOs tells me that the thermal environment is carefully designed, and part of the calibration process - if you modify this environment (by cooling or extra insulation) you modify the thermal environment, and are at risk of modifying the performance. I'd leave well alone, and run the unit in an open, breeze-free environment. 73, Murray ZL1BPU ___ 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 thermal management
In message be50c3a72eba61449c804b2c8b4ae38101ebb...@neptune.rakon.net, Murra y Greenman writes: With the FE-5680A I had the opportunity to study things in more detail. The PRS10 manual has some good info. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FE-5680A thermal management
In message be50c3a72eba61449c804b2c8b4ae38101ebb...@neptune.rakon.net, Murray Greenman writes: With the FE-5680A I had the opportunity to study things in more detail. The PRS10 manual has some good info. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. Ok, hope everyone can see what above was written by Poul and Murray respectively. ;-) For the FRS-C read page 7 (chapter 2.4 Mounting in the below manual. http://www.to-way.com/frs.pdf It says the base plate should never go above 65 deg C. -- 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] FE-5680A thermal management
- Original Message - From: Murray Greenman murray.green...@rakon.com To: time-nuts@febo.com Sent: Tuesday, June 09, 2009 6:42 AM Subject: [time-nuts] FE-5680A thermal management Leigh, I agree with Chuck. I have both an FE-5650A and an FE-5680A. With the former I was concerned about the heat, and so ran it only for short periods, until I understood what was going on. I had the impression from the data sheet that there were different heatsink options for different temperature ranges, and I now believe this led me astray. With the FE-5680A I had the opportunity to study things in more detail. There is no temperature range specification that I could find, and no particular advice in the manual regarding installation. I ran the unit from regulated 15V DC, and monitored the supply current. With no extra cooling, the steady state current was about 700mA. With air blown over it, the current increased. With the unit placed in a poly bag, the current decreased to about 650mA. By the way, the current also decreased when operated from 17V DC. This tells me that the whole structure is part of the thermal package, and we should not attempt to force down the case temperature just because the unit runs hot. My experience with high performance OCXOs tells me that the thermal environment is carefully designed, and part of the calibration process - if you modify this environment (by cooling or extra insulation) you modify the thermal environment, and are at risk of modifying the performance. I'd leave well alone, and run the unit in an open, breeze-free environment. 73, Murray ZL1BPU Murray et al, The package of both units is clearly meant to be mounted on something-the real question is how much heat sinking would that something have provided? Changing the external heatsinking to achieve the nominal supply current at the nominal supply voltage would appear to be the only simple way to operate the units as intended. I've not gone through this exercise yet with the 5650, but I suspect the amount of heatsinking used is not that critical. Using a variable speed fan to determine the 'correct' mounting plate temperature (corresponding to nominal supply current/voltage) might be a good way to start. The design of a heatsink to achieve the same base plate temperature should be a trivial exercise. Constraining the 'ambient' air temperature to an appropriate range in the vicinity of the unit should certainly help as well. Regards DaveB, NZ ___ 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 thermal management
Almost all rubidium standards DO specify the use of some form of a heat sink. For the FRK and M100 units this can be a heat sink with around 1 fins or just bolted to a metal plate or chassis. The military freq standard that had M100's in them had the unit mounted to a 5x5x.2 aluminum plate that was in turn bolted to the chassis. My Efratom PTB-100 time bases for the Tektronix TM500 mainframes have a large heat sink mounted to a FRK style oscillator. LPROs are supposed to be mounted to a metal chassis (they usually come with a thermal pad attached to them). I have seen them lose lock in free air. I saw one mounted in a piece of cell phone equipment. It was bolted to a large heat sink that formed most of the front of the enclosure. I have also seen FE-5680A's in their native habitat (again, cell phone equipment). They were mounted to a thick (1/8?) PCB around 6x16. The side of the PCB that the 5680 was bolted to had a solid ground plane. The 5650A's had one side bolted to a metal chassis. _ Hotmail® has ever-growing storage! Don’t worry about storage limits. http://windowslive.com/Tutorial/Hotmail/Storage?ocid=TXT_TAGLM_WL_HM_Tutorial_Storage_062009 ___ 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.
