AK1WI: “Vacuum Tubes: A Little Bit of Nothing in a Glass Bottle” at New England Sci-Tech ARS Meeting, November 9, 2021

New England Sci Tech logoThe New England Sci-Tech Amateur Radio Society will meet on-line and in-person on November 9, 2021 at 7 PM and feature Derek Rowell, AK1WI,  who will present on “Vacuum Tubes: A Little Bit of Nothing in a Glass Bottle.”
This talk is an introduction to the STARS project to restore a 1960s vintage Drake 2B ham-band receiver to full operation. The 2B is a vacuum tube radio, and to help understand the restoration I will introduce vacuum tubes, which were the only “active” devices available for radio design and construction until the development of semiconductor devices in the ‘50s and ‘60s.  Now, of course, they have all but disappeared from electronics.   They were power-hungry, large, hot, operated at dangerously high voltages, and needed multiple power supplies, but they were all we had at the time.
I will describe thermionic emission, the construction and operation of diodes, triodes, tetrodes, and pentodes (I bet most of you haven’t heard of most of these).  We will look at the common shapes and sizes and pinouts of vacuum tubes. Then we will look at simple power supply and amplifier circuits from the “good old days.”
I will conclude the talk with a brief look at the Drake 2B.  The one that STARS owns looks to be in very good condition, but we do not know when it was last powered up.  We will attempt an unrehearsed restoration to full operation on the morning of Saturday November 13 at NEST, taking all the recommended precautions for restoring antique radios, including capacitor replacement.  All STARS members are invited to attend.  We plan to also broadcast the restoration project on Zoom. 
For Zoom conference information, email Bob Phinney, K5TEC, at bobphinney -at- nescitech -dot- org or call 508-720-4179.

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