Uploaded March 2024 | Updated September 2026, 2 weeks ago
(To those who swear I've covered this topic before: I have; I just wasn't satisfied with my original video)
Remarkably simple and requiring no power source, crystal radios were the primary means of listening to commercial radio broadcasts until the late 1920s and early 1930s, when they were largely superseded by more sensitive tube-based heterodyne and regenerative receivers. However, they continue to be built by hobbyists and are a popular project for teaching children the basics of radio technology.
Huge shout-out to Julian Horn and United Nuclear for their invaluable assistance in putting together this video. Check out United Nuclear's fascinating catalogue at: unitednuclear.com
Medical Coils/Batteries Video: youtu.be/NufNhuWI1iA
0:00 Introduction
0:52 Spark Gap Transmitters
2:02 Coherer Receivers
3:05 Magnetic Hysteresis Detectors
4:38 Reginald Fessenden and the Dawn of AM Broadcasting
5:06 Parallel Tuned Circuits /LC Resonators
6:29 Rectifying/Envelope Detectors
7:23 Hot-Wire Barretter
8:19 Electrolytic Detector
9:18 Early Crystal Detectors
9:50 Crystal Radio Basics
12:17 Cat's Whisker Detectors
12:56 P/N and Metal-Semiconductor Junction Diodes
14:39 Later Crystal Detectors and Diodes
16:26 1923 Ariel Crystal Set
17:11 Self-powered Crystal Radios
17:50 Crystal Radio Optimization and Range
20:52 Foxhole Radios
22:27 Obsolescence of Crystal Radios
23:05 1950s Miniman Rocket Radio
24:18 Outro
SOURCES:
web.archive.org/web/20121228200010/http://www.ieee.ca/millennium/radio/radio_differences.html
earlyradiohistory.us/1917de.htm
eng.libretexts.org/Bookshelves/Materials_Science/Supplemental_Modules_(Materials_Science)/Semiconductors/Metal-Semiconductors_Contacts
radiomuseum.org/r/graves_ariel_crystal_set.html
electronics-notes.com/articles/radio/radio-receivers/how-does-crystal-radio-work.php
electronics-notes.com/articles/history/radio-receivers/cats-whisker-crystal-radios-sets.php
nutsvolts.com/magazine/article/remembering-the-crystal-radio
(To those who swear I've covered this topic before: I have; I just wasn't satisfied with my original video)
Remarkably simple and requiring no power source, crystal radios were the primary means of listening to commercial radio broadcasts until the late 1920s and early 1930s, when they were largely superseded by more sensitive tube-based heterodyne and regenerative receivers. However, they continue to be built by hobbyists and are a popular project for teaching children the basics of radio technology.
Huge shout-out to Julian Horn and United Nuclear for their invaluable assistance in putting together this video. Check out United Nuclear's fascinating catalogue at: unitednuclear.com
Medical Coils/Batteries Video: youtu.be/NufNhuWI1iA
0:00 Introduction
0:52 Spark Gap Transmitters
2:02 Coherer Receivers
3:05 Magnetic Hysteresis Detectors
4:38 Reginald Fessenden and the Dawn of AM Broadcasting
5:06 Parallel Tuned Circuits /LC Resonators
6:29 Rectifying/Envelope Detectors
7:23 Hot-Wire Barretter
8:19 Electrolytic Detector
9:18 Early Crystal Detectors
9:50 Crystal Radio Basics
12:17 Cat's Whisker Detectors
12:56 P/N and Metal-Semiconductor Junction Diodes
14:39 Later Crystal Detectors and Diodes
16:26 1923 Ariel Crystal Set
17:11 Self-powered Crystal Radios
17:50 Crystal Radio Optimization and Range
20:52 Foxhole Radios
22:27 Obsolescence of Crystal Radios
23:05 1950s Miniman Rocket Radio
24:18 Outro
SOURCES:
web.archive.org/web/20121228200010/http://www.ieee.ca/millennium/radio/radio_differences.html
earlyradiohistory.us/1917de.htm
eng.libretexts.org/Bookshelves/Materials_Science/Supplemental_Modules_(Materials_Science)/Semiconductors/Metal-Semiconductors_Contacts
radiomuseum.org/r/graves_ariel_crystal_set.html
electronics-notes.com/articles/radio/radio-receivers/how-does-crystal-radio-work.php
electronics-notes.com/articles/history/radio-receivers/cats-whisker-crystal-radios-sets.php
nutsvolts.com/magazine/article/remembering-the-crystal-radio
![A-4 Gun Bomb Rocket Sight: The Sabres Edge
[In case you are wondering, it is Fringe Theatre Festival time and I shaved my beard for my production. It will return shortly.]
Fitted to many 1950s/1960s American jet fighters, the A-4 Gun Bomb Rocket Sight system incorporated a gyroscope, ranging radar, and analogue computer to calculate the correct deflection for various aerial weapons. Though initially plagued with technical issues and disliked by pilots as cumbersome to use, the A-4 and its predecessor the A-1C(M) helped American pilots in Korea and subsequent conflicts to achieve extremely high kill ratios.
Gunsight video Pt.I: https://youtu.be/evwD36mtj5s
Gunsight video Pt.II: https://youtu.be/CDdrggsC3VY
Gunsight video Pt.III: https://youtu.be/XcsNt9oaZss
Gun Camera video: https://youtu.be/UrX4mnaqJBE
0:00 Intro
1:33 A-1C(M) Sight
2:36 Exterior Controls
5:52 Peripheral Controls 1
6:46 Rocket Firing System
7:52 Gunsight Computer
8:45 Bomb Aiming System
9:44 Peripheral Controls 2
10:37 Interior Components
12:22 Combat Performance
13:46 Outro
SOURCES
https://usaf-sig.org/index.php/references/downloads/4-technical-orders/38-type-specific/56-f-86-sabre-north-american
https://www.glennsmuseum.com/items/a4_sight/
https://apps.dtic.mil/sti/tr/pdf/AD0017568.pdf
https://grinnellidesigns.github.io/f-100d-manual/Weapon_System/a-4-gunsight.html
https://www.sas1946.com/main/index.php?topic=3406.0 A-4 Gun Bomb Rocket Sight: The Sabres Edge](https://i.ytimg.com/vi/6OnhXklkPsw/mqdefault.jpg)









