3 ms·
So they used twisted pair DC cabling to minimize torque errors due to DC magnetic field (and the torque follows direction of cavity orientation), but.... I'm wo
by madengr 10y ago
So they used twisted pair DC cabling to minimize torque errors due to DC magnetic field (and the torque follows direction of cavity orientation), but.... I'm wondering if there is DC current circulating in the cavity due to rectification from oxides or impurities on the copper surface; i.e. Passive Intermodulation Distortion (disclaimer I'm an RF EE). They said the torque was strongly non-linear with applied power; which is a hint.
DC cavity currents were not listed as a potential error source, but these phenomenon could show up with high power and high Q.
Anyway, I just emailed a couple of the NASA guys; see what they say.
- isaiahg 10y agoWould be interested to see how they reply.
- londons_explore 10y agoI don't understand why they don't just use a battery to power the experiments... Now all power supply related concerns are gone.
- madengr 10y agoNo, the RF sources (magnetron) still require DC current.
- walrus01 10y agoon the scale of micronewtons being measured, batteries change significantly thermally as they're discharged. You would have to account for the chemical and thermal activity of the battery which is not a 100% inert thing.