crystal controlled transmitter circuit was manufactured and used in an early police in-car video system. Let me tell you the story behind it. For years I published
electronic plans. I had a customer down in El Dorado, Arkansas by the
name of Don Shryock. He bought everything I produced.
Years ago he sent me a letter ( No Email Back Then ) that he was
manufacturing a new IN-CAR video system for police cars.
was mounting a camera on the front window, and a system in the trunk
using a modified regency scanner that I had described in a newsletter –
The Tech-2008 and would like to implement the Pro-033a crystal
controlled transmitter circuit as his master transmitter to sell the
system commercially. I gave him my approval without any royalties. Thus
the Police IN-CAR Viper Video system was born from Shryock
He sold thousands of these systems to virtually
every Police Department in America and more Federal Agencies that I can
If you ever watched some of the earlier versions of “COPS”, this
crystal controlled transmitter circuit was the one that was worn on the
officers belt. When he got out of his patrol car, he switched on the
transmitter which activated the system in the trunk of his patrol car.
If you want to know more about how he put his system together,
I have written a book on how he did it with much more called “Packaging
and Repackaging For Law Enforcement Agencies” that you can purchase
below, and just click into the link.
Don passed away a few years ago
like many others in my craft, but the
technology is still good and this crystal controlled transmitter
circuit can be applied to modern day uses. I have scanned my originally
functional prototype schematic and it is shown below. C1 and C2 and C3
are 2 to 22 Pf Adjustable Capacitors. The special Coil forms L1 and L2
shown are Digi-Key Electronics 3368k-ND Coil Forms Shown in the image
below. Any fiber washers that you can find at Home Depot, etc. will
work fine as long as they are the same size of the Digy-Key Washer.