Hi > On Oct 21, 2020, at 8:40 AM, Wannes Sels <[email protected]> wrote: > > There are conflicting requirements regarding temperature in Rb's: > > - For best performance, the rubidium and quartz oscillators must be kept at > a high and stable temperature. > - For reliability, the supporting electronics must be kept at a lower > temperature. > > The heater takes care of the high temperature. The stability of the > temperature can be improved by increasing the thermal mass, i.e. adding a > block of aluminium or copper.
If you are designing the internals of the OCXO or Rb from scratch, this may help things. If you have a part of eBay … likely not so much. > The electronics can be kept cooler with a heatsink, and forced ventilation > if needed. > > When you stick both the electronics and physics in a small package, this > becomes more difficult. For the PRS-10 some form of heatsink is pretty much > required to keep the electronics cool enough. Although I seem to remember > reading somewhere that the "benchtop" heatsink they offer now is lighter > than older units. The PRS-10 is hardly unique in this regard. All of the small Rb’s ( = anything other than a 5065 sized unit) that I’ve seen really do need a heatsink in order to live a long and happy life. Bob > > If the room temperature is not stable enough, you might want to increase > the size of the heatsink and add a fan. This reduces the temperature swing > inside the unit, while still cooling the electronics, at the cost of > increased power draw for the heater. > > > > > On Wed, Oct 21, 2020 at 5:38 AM Hal Murray <[email protected]> wrote: > >> >>> I spent a lot of years buying Rb’s and putting them on small heatsinks. >> I >>> always was disappointed in their reliability. That continued to be the >> case >>> up to the point that the baseplate temp’s got into the 40C region. In my >>> case, that took a fan …. >> >> How well did it work if the heat sink wasn't small? What is your version >> of >> small? >> >> Do you have any data (or vague memories) of how much it helps to orient >> the >> heat sink so the fins are vertical so they encourage warm air to flow up >> past >> the fins? >> >> -- >> These are my opinions. I hate spam. >> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
