Pre-war Crystal Holders Part 2: ICA 415 “Button” Crystal Holder

An Insuline Corp. of America (ICA) No. 415 Holder. I met W9QUF (he was W0QUF after the war) at a hamfest somewhere in Nebraska or Iowa years ago, though I acquired this recently. When names are attached to things I leave them as part of the history.

In the last article I made mention of using a small button as an electrode rather than a large metal plate. This was a pretty common technique for getting quartz crystals to oscillate at higher frequencies with flat (and easier to manufacture) electrodes. We’re going to look at the button version of the ICA 415 holder to illustrate how it works.

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Pre-war Crystal Holders Part 1: Bliley BC2 Holders

A BC2 in need of some love….

This is the first in a series of articles on pre-WWII quartz crystal restoration. This article walks through the restoration of an early 30’s crystal holder that is fairly common on the surplus market, pointing out some of the characteristics and challenges that are unique to 1930’s crystal technology.

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