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Dallas Historical Society 
 July Special Events
In This Issue
Brown Bag Lecture
The Fourth at Fair Park
Quick Links
The Dallas Historical Society is pleased to bring you a list of special events for July 2010. For more information please contact us at 214-421-4500 or visit www.dallashistory.org.
Thank You,
Dallas Historical Society

Do you know what a Western Electric Model 7021 crystal-oscillator is?  Well, I didn't either when  Ed Millis stopped by our office the other day  to donate one to our collection. I'm ashamed to say that my first response was "a what"?  This one came from the WRR radio station and probably dates from the 1930s.For those of you with a technological bent, a quick check of the internet told me that a crystal oscillator is an electronic circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. This frequency is commonly used to keep track of time, to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is the quartz crystal, so oscillator circuits designed around them were called "crystal oscillators." In short, it is a very precise triode vacuum tube.
The oscillator came to us from the estate of  Earl D. McDonald, by way of his widow, Donna. Mr. McDonald helped take apart the old WRR transmitter on Flag Pole Hill back in the early 1980s and had the foresight to save this artifact from Texas' first, licensed, radio  station.
MARDI GRASWRR received its license at 1310 Kltz in 1921 was originally used by the city's fire department to broadcast emergency information back and forth between the city's firefighters. As the story goes, when the station was not being used for emergency communications, the firefighters would play music and tell jokes. By 1926, WRR had evolved into a commercial station and is still very popular today,  as the only station playing classical music exclusively in the Dallas market.. Like a lot of you, I grew up listening to WRR, so I can only imagine how many hours of entertainment this oscillator helped bring me.
Things like this make me think about just what is an historic artifact? This was, after all, just some inanimate bit of electronics that someone plugged into a transmitter way back in the 1930s. It sat there for decades buzzing away unnoticed and, seemingly, unimportant. Still, when you think of all the music and historical information that it helped broadcast, from the bombing of Pearl Harbor to the Challenger explosion, it is hard to think of it as inanimate.
Were you listening to WRR when you heard about President Kennedy's assassination or when we landed on the moon? Well, that information first passed through this oscillator to get to you. This crystal oscillator is as much an historic artifact as any book or photograph we have. Thank you, Mr. and Mrs. McDonald. 
-Ed Owens
 Sponsored by          
MARDI GRASBrown Bag Lecture 

Texas food festivals and the story of the food discovered by the Spanish in 1517 when they arrived in Texas and how it impacted what we eat in daily Texas life.
July 14th, Noon-1:oo
Presented by: Rose-Mary Rumbley, author, local historian and personality. 
Clampitt Paper's headquarters, 9207 Ambassador Row, Dallas, TX 75247 

Admission is free 
 The Fourth at Fair Park