19-Aug-2006

1. Introduction

I've seen several General Radio quartz bars, for example the GR 1190a, which is spring mounted 100 kc bar mounted inside an double insulated thermal chamber for use as a precision frequency standard.

Below is the first time I've seen a 50 kc quartz bar. Not sure where it came from.

2. Photos

50 kc (that's 50 kHz for you young ones):

The crystal sits on a 3½" bakelite base and the black anodized aluminum cover is about 3¼" x 1½". Palm sized:

Outside photos (top, bottom, left, right):

Inside photos:

Close up of upper pressure mount:

Close up of super thin gold(?) wire leads:

A bar in the hand is worth two in the....

Nameplate:

Here are the original photos of the crystal when it first arrived. Note that the quartz crystal bar was skewed. It is mounted rather loosely and so it's not surprising it would shift during shipping. Not sure if the end caps should be flush against the bar. I did not attempt to adjust the end screws.

3. Patents

1931 patent 1,967,184 describes a "vibrator apparatus"

General Radio Quartz Oscillator (Precision Frequency Standard) patents:

• 1931 patent 1,967,184 Vibrator Apparatus
• 1931 patent 1,967,185 Temperature Control Apparatus
• 1933 patent 2,012,497 Electrical System
• 1933 patent 2,029,358 Electromechanical Vibrator

See also GR 1190A