Book Report: Getting Acquainted with Radio
Getting Acquainted with Radio is yet another book available on the irreplaceable Worldradiohistory web site:
https://worldradiohistory.com/BOOKSHELF-ARH/A.P.Morgan/Getting%20Aquainted-With-Radio-Morgan.pdf
One of the many Alfred P. Morgan books on the hobbyist bookshelf of the Worldradiohistory site:
https://worldradiohistory.com/BOOKSHELF-ARH/Bookshelf_Hobbyist.htm
Usually when finding one of these older books I'll just browse through it and then close the file. But this time I decided to read the book all the way through. Of course since it is a 1940 book it features the vacuum tube almost exclusively (crystal detectors are mentioned). And unlike most of Morgan's books this one is less on building and more on the theory of radio.
A couple of items stood out to me:
1) unlike a previous Morgan book mentioned in this blog post:
https://wb9kzy.blogspot.com/2022/07/multi-wire-antennas-early-20th-century.html
Morgan doesn't mention Tesla at all ! No entry in the index. He does mention Edwin Armstrong quite a bit though.
2) this power supply circuit was interesting to me:
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| from page 221 |
It's a conventional 2 diode, full-wave, center tapped circuit but the interesting thing to me was the addition of the two .002 uF caps across the two diodes. He mentions that this will suppress tunable hum. I had to add .01 uF caps to my 12V supply to combat tunable hum with a 40 meter Ramsey DC receiver:
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| the bypass caps are the dark red on the black Schottky diodes |
I had to use 4 caps with the bridge rectifier circuit but it's the same idea: the wisdom of the pioneers translated from vacuum tube diodes to Schottky diodes ! The idea is to bypass any RF that might be radiated from a VFO.
Anyway an interesting book and I always like to see Morgan's wonderful diagrams and drawings - glad I finally read it.
Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm