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In my last video on the 'Gibson Girl', survival radio I went over the basic design, controls, and accessories of the WWII-era SCR-578 model.In this follow-up video, I peer beneath the case of the SCR-578 and the post-war AN/CRT-3 variant to reveal the ingenious engineering behind these classic pieces of emergency signalling gear.

A huge thanks to Julian Horn for his invaluable assistance with this video.

Original Gibson Girl Video:    • SCR-578 'Gibson Girl' Survival Radio:...  


*NOTE: the 12SC7 valve is a double TRIODE, not diode; I misspoke.

0:00 Introduction
1:11 Evolution of the 'Gibson Girl'
6:15 SCR-578 Disassembly
6:55 SCR-578 Power Source: Gearing and Auto Signalling Cams
8:20 SCR-578 Power Source: Dynamo and Power Regulation System
10:24 SCR-578 Transmitter: Peripheral Features
10:59 SCR-578 Transmitter: Basic Design
11:28 SCR-578 Transmitter: Audio and RF Oscillator Circuits
13:25 SCR-578 Transmitter: Antenna Tuning System
13:42 AN/CRT-3 Disassembly
14:00 AN/CRT-3 Power Source: Gearing and Signalling/Frequency Switching Cams
14:42 AN/CRT-3 Transmitter: 8280/8364 kHz Tank Circuit
15:20 AN/CRT-3 Transmitter: Frequency Switching System
15:41 AN/CRT-3 Transmitter: Antenna Indicator System
16:56 Outro

SOURCES:
http://www.radiomanual.info/schemi/Su...
http://www.radiomanual.info/schemi/Su...
http://www.wftw.nl/gibsongirl.html