Andy Wallace, KA1GTT, writes on the Billerica Amateur Radio Society website:
I’m very happy to announce that our next virtual speaker will again be David Kruh, WB2HTO, with his talk entitled Stories from the Shop – this time, Part 2, the sequel! David enjoys repairing antique radios – ones using vacuum tubes – and has learned a lot about how they function and also about why they were designed and produced the way they were. I have enjoyed David’s blog posts immensely and he does a great job connecting the dots between the cutting-edge electrical engineering work of today and the heritage that came before.
Working on antique radios takes a special kind of detective skill. Often the circuits are simple. Five-tube radios were common. But in producing consumer electronics, manufacturers had to cut costs which can leave today’s hobbyist scratching his or her head as to why performance or safety could be at risk. Dave has a great slide deck prepared with illustrations of what he has encountered and will explain the logic behind the original design and the way to get these antique sets playing safely again. Remember, there is real radio theory inside a broadcast-band radio. He will field questions after each section of his presentation as well.
This should be a fascinating talk! He was only able to get through two subjects last speaking engagement, so this time he will finish up with “Philco and the State of the Art” and “A Bad Reputation – the Story of the 6X5 Rectifier”.[Full story]