I wonder how peltier devices would work for this application. Coupled with a temperature feedback servo they could be used to heat/cool the rubidium. Does anyone know if they have any electromagnetic field issues with them, the ones I have seen seem to be completely enclosed in aluminium which should act as a Faraday cage. They have the potential of providing a large thermal transfer capability compared with passive devices.
73, Steve 2009/12/25 Joe Gwinn <[email protected]>: > At 10:06 PM +0000 12/23/09, [email protected] wrote: >> >> Date: Thu, 24 Dec 2009 09:46:13 +1300 >> From: Bruce Griffiths <[email protected]> >> Subject: Re: [time-nuts] Cheap Rubidium >> To: Discussion of precise time and frequency measurement >> <[email protected]> >> >> Joe Gwinn wrote: >>>> >>>> Date: Thu, 24 Dec 2009 08:57:42 +1300 >>>> From: Bruce Griffiths <[email protected]> >>>> Subject: Re: [time-nuts] Cheap Rubidium >>>> To: Discussion of precise time and frequency measurement >> >> >> <[email protected]> >>>> > > [snip] > >>> >> Distributed heating using wire wound or printed heaters perhaps, but >>> to >>>>> >>>>> reduce the associated magnetic field bifilar winding should be >>>>> considered. >>>> >>>> Non-inductive power resistors, which are commercially available, have >>>> very low magnetic fields. >>>> >>>> The low-inductance resistors have Ayrton-Perry windings, which are >>>> bifilar. >> >> No, Ayrton-Perry windings arent bifilar. >> >> Classically a flattened helical winding was made on a insulating card. >> An identical winding was then wound in the opposite direction on top of >> the first winding and the 2 were connected in parallel. >> The idea being that the small magnetic field produced by one flattened >> helix is cancelled by that of the other flattened helix. > > True enough - while there are two conductors, they are not close and > parallel. > > Anyway, the point is that non-inductive components by definition have low > magnetic fields, and that non-inductive power resistors are common. > > To eliminate the field from the loop of resistors, one can have a linear > string of A-P resistors in series, with a pair of return wires in parallel, > with the return wires on either side of the resistor string, thus reducing > the effective loop area. > > Joe > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
