# Degaussing a Hewlett-Packard Cesium Atomic Clock

**URL:** <https://scanalyst.fourmilab.ch/t/degaussing-a-hewlett-packard-cesium-atomic-clock/2204>\
**Category:** Tracking with Closeups\
**Tags:** hewlett-packard, atomic-clock, hp-10638-degausser, cesium-frequency-standard, hp-5061b-cesium-clock\
**Created:** [26 October 2022 13:10 UTC](https://scanalyst.fourmilab.ch/t/degaussing-a-hewlett-packard-cesium-atomic-clock/2204 "2022-10-26T13:10:20Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![johnwalker](https://scanalyst.fourmilab.ch/user_avatar/scanalyst.fourmilab.ch/johnwalker/32/17415_2.png) [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\
**Post date:** [26 October 2022 13:10 UTC](https://scanalyst.fourmilab.ch/t/degaussing-a-hewlett-packard-cesium-atomic-clock/2204/1 "2022-10-26T13:10:20Z")

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[![](https://scanalyst.fourmilab.ch/uploads/default/original/2X/b/b60e9cc829878b17bfc93f9410d0ec5eca660795.jpeg "HP 10638A Degausser: checking vintage HP equipment with more vintage HP equipment!") ](https://www.youtube.com/watch?v=hvxX5A1nTIU)

To obtain the maximum accuracy from your Cesium clock, there must be no residual magnetic field which could affect the oscillation of the cesium beam. To ensure this, the old Hewlett-Packard applied their legendary over-engineering skills to this de-gausser, which applies a precisely calculated exponentially decreasing alternating magnetic field to coils engineered into the cesium ion tube. The test equipment required for this procedure weighs even more than the atomic clock.

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**Author:** ![1789Libertarian](https://scanalyst.fourmilab.ch/user_avatar/scanalyst.fourmilab.ch/1789libertarian/32/1089_2.png) [@1789Libertarian](https://scanalyst.fourmilab.ch/u/1789Libertarian)\
**Post date:** [27 October 2022 17:24 UTC](https://scanalyst.fourmilab.ch/t/degaussing-a-hewlett-packard-cesium-atomic-clock/2204/2 "2022-10-27T17:24:31Z")

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And here is a real degaussing machine:

[![](https://scanalyst.fourmilab.ch/uploads/default/original/2X/e/e3127f5475171247667d3dc788dfde122f9f92c3.jpeg "King's Bay Submarine Degaussing Facility") ](https://www.youtube.com/watch?v=DnbkfisD1yg)

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**Author:** ![civilwestman](https://scanalyst.fourmilab.ch/user_avatar/scanalyst.fourmilab.ch/civilwestman/32/25_2.png) [@civilwestman](https://scanalyst.fourmilab.ch/u/civilwestman)\
**Post date:** [27 October 2022 17:38 UTC](https://scanalyst.fourmilab.ch/t/degaussing-a-hewlett-packard-cesium-atomic-clock/2204/3 "2022-10-27T17:38:15Z")

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Where does the sub go for its ‘treatment’? Underwater? Does this device move to a drydock?

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**Author:** ![1789Libertarian](https://scanalyst.fourmilab.ch/user_avatar/scanalyst.fourmilab.ch/1789libertarian/32/1089_2.png) [@1789Libertarian](https://scanalyst.fourmilab.ch/u/1789Libertarian)\
**Post date:** [27 October 2022 17:44 UTC](https://scanalyst.fourmilab.ch/t/degaussing-a-hewlett-packard-cesium-atomic-clock/2204/4 "2022-10-27T17:44:36Z")

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If memory serves the boat just surfaces inside the mechanism. Or more likely it is gently guided into the mechanism from one of the ends. I wasn’t a bubblehead so I am not exactly sure. I served on a Destroyer, also known as a target.

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**Author:** ![civilwestman](https://scanalyst.fourmilab.ch/user_avatar/scanalyst.fourmilab.ch/civilwestman/32/25_2.png) [@civilwestman](https://scanalyst.fourmilab.ch/u/civilwestman)\
**Post date:** [27 October 2022 17:45 UTC](https://scanalyst.fourmilab.ch/t/degaussing-a-hewlett-packard-cesium-atomic-clock/2204/5 "2022-10-27T17:45:56Z")

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> [@1789Libertarian](#):
>
> a target

Usually a moving target, I imagine.

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**Author:** ![1789Libertarian](https://scanalyst.fourmilab.ch/user_avatar/scanalyst.fourmilab.ch/1789libertarian/32/1089_2.png) [@1789Libertarian](https://scanalyst.fourmilab.ch/u/1789Libertarian)\
**Post date:** [27 October 2022 17:46 UTC](https://scanalyst.fourmilab.ch/t/degaussing-a-hewlett-packard-cesium-atomic-clock/2204/6 "2022-10-27T17:46:12Z")

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Depends on the helmsman!