Uploaded February 2024 | Updated September 2026, 2 weeks ago
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: youtube.com/watch?v=odqEA-8OxMw
*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:
radiomanual.info/schemi/Surplus_NATO/AN-CRT-3_Gibson_girl_serv_user_AN16-30CRT3-2_1947.pdf
radiomanual.info/schemi/Surplus_NATO/SCR-578A_B_serv_user_AN08-10-94_1943.pdf
http://www.wftw.nl/gibsongirl.html
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: youtube.com/watch?v=odqEA-8OxMw
*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:
radiomanual.info/schemi/Surplus_NATO/AN-CRT-3_Gibson_girl_serv_user_AN16-30CRT3-2_1947.pdf
radiomanual.info/schemi/Surplus_NATO/SCR-578A_B_serv_user_AN08-10-94_1943.pdf
http://www.wftw.nl/gibsongirl.html








![Reflex Gunsights Part II: Gyro and Radar Gunsights
*NOTE: I state that the moisture sensing paper is impregnated with Copper Sulphate. I was mistaken: it is Cobalt Chloride. *
Thank you to FlexiSpot for sponsoring this video. Upgrade your setup with FlexiSpot and pick up your favorite one! Use my code YTE7P50 to get EXTRA $50 off on the E7 Plus and E7L standing desk.
USA: https://bit.ly/47VjChA
CAN: https://bit.ly/4my0NqY
While reflector or reflex gunsights offered numerous advantages over traditional iron sights, they still did not solve the fundamental problem of aerial gunnery: computing the correct deflection or lead needed to hit a distant moving target. As a result, in the early 1940s British and German engineers developed Gyro Gunsights, which used gyroscopes to measure the aircrafts rate of turn and automatically compute the aircrafts rate of turn - and in turn the correct deflection. Highly effective in combat, just after WWII gyro gunsights were further enhanced via the integration of radar to automatically input the target range.
Reflex Gunsights Part I: https://youtu.be/evwD36mtj5s
Window Chaff video: https://youtu.be/qLEsI-TdAgE
TIFO Microwave Oven video: https://www.youtube.com/watch?v=Xetyi84Fu10&t=16s&pp=ygUbdG9kYXkgaSBmb3VuZCBvdXQgbWljcm93YXZl
TIFO Battle of the Beams video: https://www.youtube.com/watch?v=j-TPOppvpMs&pp=ygUkdG9kYXkgaSBmb3VuZCBvdXQgZm9yZ290dGVuIHRlY2ggd2Fy
TIFO Operation Biting video: https://www.youtube.com/watch?v=mBwYO_N5bh0&pp=ygUpdG9kYXkgaSBmb3VuZCBvdXQgc3RlYWxpbmcgaGl0bGVyJ3MgcmFkYXI%3D
0:00 Introduction
1:13 FlexiSpot Ad Integration
3:21 Gyro Gunsights Origins
5:07 G.G.S. Mk.I
6:30 G.G.S. Mk.II
6:54 G.G.S. Mk.IV Overview
9:06 Operating Procedure
12:51 Internals: Fixed Reticle
13:59 Internals: Gyro System
15:36 G.G.S. Mk.I Internals
16:07 Internals: Ranging System
16:24 Internals: Desiccant, Camera, Retractible Mount
17:57 Production and Combat Use
19:15 German Gyro Gunsights
20:22 Radar Gunsights
22:19 G.G.S. Mk.VIII
23:19 APG-30
23:42 Outro
SOURCES
https://ww2aircraft.net/forum/threads/gyro-gunsights.50788/page-2
https://prc68.com/I/NavyMk18GunSight.html#Patents
https://patents.google.com/patent/US2229645A/en
https://militaryantiquestoronto.com/product/canadian-rcaf-vampire-jet-aircraft-gun-sight-mk-4e-ferranti/
https://www.ibiblio.org/hyperwar/USN/ref/Ordnance/GS-Mk14/index.html
https://www.airwar.ru/other/manuals/[aviation] - [manuals] - Gyro Gun Sight Mk 5B and 5D.pdf
https://www.aviatorsdatabase.com/wp-content/uploads/2013/07/Gyro-gunsights.pdf
https://www.airministrymilitaria.com/en-GB/aircraft-parts/gyro-gunsight-and-retractable-mounting/prod_10573 Reflex Gunsights Part II: Gyro and Radar Gunsights](https://i.ytimg.com/vi/CDdrggsC3VY/mqdefault.jpg)

