Crystal Radios: No Batteries? No Problem!

(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primary means of listening to commercial radio broadcasts until the late 1920s and early 1930s, when they were largely superseded by more sensitive tube-based heterodyne and regenerative receivers.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: • Medical Coils: Zapping...
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/201212282...
earlyradiohistory.us/1917de.htm
eng.libretexts.org/Bookshelve...
www.radiomuseum.org/r/graves_...
www.electronics-notes.com/art...
www.electronics-notes.com/art...
www.nutsvolts.com/magazine/ar...

[@Woffy.]

As a lad during a very hot summer I visited my younger cousin Adrian, I showed him how to build a Crystal set from scrap wire etc. He told me just before his death that he was so fascinated by this magical thing we had built that he went on to study Radio, I only just found out his job was designing receivers for military satellites. Great channel, old school just the way we like it. I wish you were my teacher.

[@foxxy46213]

That is so cool. You showed him something interesting that shaped his whole life. amazing how one little thing can change someone's whole life.

[@Woffy.]

Everyone should make a crystal set it is truly magical to a young mind, thank you Foxxy for your kind words, I only learnt of some of Adrian's achievements in "special radio stuff" when he was gone apparently he developed some funky modulation thingy. We built that crystal set in the mid 60's I can see us now unravelling toilet roll for the cardboard tube to make the coil. His last call to me was to tell me he remembered the set and he wanted me to know how much it meant to him. He died a few days later.

[@foxxy46213]

@@Woffy. No worries, I love stuff like that an how one little thing or moment can change absolutely everything. I've not thought about them since I was a kid an stuffs more freely available in the net so might have a go an make one from some scrap

[@Woffy.]

Go for it, I think I will do the same. @@foxxy46213

[@kayakMike1000]

Sorry for your loss. Sounded like a great engineer.

[@darrylday30]

Built one at the age of 10 from a library book. My dad had all the parts in little glass jars hanging from the ceiling. 40 years later I found myself teaching basic AC electricity to aircraft maintenance apprentices. I am grateful.

[@Woffy.]

" From little Acorns grow great Oak's " Your memory of a special moment ......... What I like about this channel are the long lost memories it restores. It really is a pleasant few minuts in my day.

[@jgharston]

Yes: Ladybird Book How To Build A Radio, also around age 8 or 9 or so.

[@travisadkins5498]

Love this story!!❤

[@paulmaxwell8851]

I received a cheap crystal radio kit for Christmas in about 1966. I had to wind the coil, assemble the parts etc. It didn't work. My grandfather, an aviation radio technician, came over, found the problem and replaced the 1N34 germanium diode. Presto! It worked! I thought he a was a genius. I spent many, many nights listening to radio stations thousands of miles away when I should have been sleeping.

[@briandawkins984]

You sound like me I got a crystal radio set about 1968. I didn’t sleep much after that. I was 10.

[@rodchallis8031]

It's like the Crystal Radio is The Spirit of Radio.

[@davidmacphee3549]

Rush, My home band in Toronto

[@RambozoClown]

Great video. As a kid I read about trench or foxhole radios, and was amazed when I built one and it worked. Razor blade, pencil lead, coil wound on a toilet paper core, the whole shebang. I even surprised my dad.

[@foxxy46213]

Same way I saw them. But had no clue on how to build one an even my library had no info...or I wast just young an looking in wrong place. But I did remember that in one film they put the set in a helmet to amplify it...an I do that now with my phone in a bowl😂

[@spvillano]

@@foxxy46213mom grew up during the Great Depression and WWII, she told me about listening to a few crystal radios, whose earpieces would be put into a glass bowl so that those gathered around could hear the news.

[@Ed_Stuckey]

I built my first crystal set at about seven years of age. That was ~1950. It was like magic. I've been interested in all things electrical and electronic since.

[@chrisgraham2904]

I built my first crystal radio at 9 years old in 1962 as a project in Boy Scouts. Even then, I was amazed at the technology that performed without batteries or plugged into a wall receptacle. Stringing an antenna wire across the length of my bedroom ceiling and hooking the ground clamp to the hot water radiator, I was tuned into the local rock-n-roll AM station, listening through a single piezo earpiece. My mother, who came from London, England, remembered well her family's first crystal radio that required manipulation of the "cat's whisker" to maintain a broadcast signal. Knowledge of crystal radio technology will be valuable information to have after the zombie apocalypse.

[@chrisgraham2904]

To add to my comment: I just checked and am very pleased to see that AMAZON does carry a number of kits, with all the parts, for building a crystal radio, starting at around $20. That's definitely going to be a stocking stuffer for my grand daughter this year for Christmas and we'll build it together.

[@blueeyeswhitedragon9839]

I won the "Rocket Crystal Radio" in a newspaper contest and loved the way it picked up our local AM radio station and played music, battery free, while Imwas in bed getting ready to go to sleep. The good old days.

[@carlosanvito]

It was the early 1960s. My grade school teacher gave us an assignment to pick up a book at the bookmobile and write a report. None of the books interested me, except for a book by Alfred Morgan, called the Boy's First Book of Radio and Electronics. I was instantly hooked. I built one of the crystal radios and was fascinated that I could actually do that. Fast forward, that interest resulted in me studying electrical engineering in the early 70s which led to a fabulous career. All that, thanks to the humble crystal radio. Too bad kids don't do things like that anymore.

[@boxcarz]

Oh, THAT Alfred Morgan? I have one of his other books, "Things a boy can do with electrochemistry!" It's one of my favorites among my collection, which I admit is partly because it casually mentions going down to the "general store" and picking up some asbestos paper for one recipe like it's nothing at all. Ah, the 50s.

[@oldbatwit5102]

@@boxcarz In the late sixties, as a thirteen year old, I would regularly visit the local chemist to buy sulphur, potassium nitrate, charcoal, magnesium and a bunch of other stuff. It was like a toyshop for me. Oddly, I had to sign for the magnesium but not for anything else. I also had no problems buying matches, 20 boxes at a time, meths, lighter fluid, fireworks etc.

[@20chocsaday]

I failed.

[@ScriptCatz]

I’m 16 and do all sorts of junk like that! I’ve admittedly never made a radio but I’ll dick around with high voltage electronics and old 80s computer systems

[@rihardsrozans6920]

Kids still do all kinds of neat stuff you old fart

[@shmehfleh3115]

My grandmother lived in a relatively small rural community in Illinois, about 30 miles away from St. Louis. Her farm, as well as the rest of the town received its electricity from a diesel generator located in the nearby firehouse. It was only run for a few hours each day, during which everyone ran their washing machines, vacuumed, listened to their radios, or did whatever else required electricity before it was shut off again. I don't think her community was tied to an official 24/7 energized grid until after WWII, and my grandfather, who was a lineman for most of his career, helped do it.

[@shawn.the.alien423]

When I was in Junior High back in the '90s, I had a teacher (Mr. Dollar) who did an exploratory class on radio, and something we got to do was build crystal radios from kits. It taught me a lot about the basics of radio. I have two nephews that, when they get old enough, I'm gonna find some kits and teach them what I learned

[@timd1833]

In 1958, I was 7 years old. My brother-in-law's step-father had a small plastic box with a wire coming out of it with an alligator clip on the end. Also had another wire with an earphone coming out of the other side. He let me listen to it. He opened the back of the plastic box and there was hardly anything in it. Fascinated me! We had a radio at home but it had to be plugged into the wall and turned in different directions to pick up various stations. I wasn't allowed to touch that radio. The crystal set had only one dial, 1-10, and turning it slowly would change the stations. I credit Mr W for getting me interested in electronics, building Heathkits in high school, electronics in the service and then a career with 2 electronics companies. Retired now!

[@Evergreen64]

I hear your "Spirit of Radio" sir. Longtime RUSH fan here. Great video!

[@Albertkallal]

I had many crystal radios as a child - several from Radio Shack. But, out of of all the ones I ever used? That rocket radio blew them all away!!! - don't know why, but wow oh wow - they work beyond well...... And they were dirt cheap - available at the downtown Army and Navy store. I used take my to school, and just clip the alligator clip to the school chain link fence, and it worked rather well. (Grandin School) At home? Just clipped to the heater vent by my bed - listened to CFRN and Irv Shore in the morning. And to not be puny? That CFRN signal was crystal clear. Very cool, and no batteries. Loved that Rocket radio as a child - and it worked really well.

[@Ni999]

Can confirm. 👍👍

[@gtracer6629]

I had one of those rocket radios in college. I would clip the wire to the radiator in my room. About the only thing I can pick up was the compass radio station what was still kind of cool cuz it had no batteries or anything.

[@-danR]

Yes, the rocket radio. My Dad gave me one as a present around 1960, not quite the same design, but prob. the same guts. It wasn't just an intriguing curiosity, it was quite practical as a radio. Every night I lay in bed listening to the local station in Vancouver playing BBC's The Goon Show. So instead of wasting a pointless hour or so sleeping, I was getting an education...

[@briandawkins984]

I also grew up in St Albert until Gr. 4. I attended Sir Alexander Mackenzie. I had a crystal rocket radio when I was 7. I could pick up CHED, CFRN, CJCA amongst others. Those little radios made in Japan? Were impressive considering their simplicity. I would wind the antenna lead around my bed frame. That improved reception capability.

[@Albertkallal]

@briandawkins984 Great memories, thanks for sharing. As noted I had a number of crystal radios but those rocket radios worked the best.

[@3DJapan]

I had a Radio Shack kit as a kid to make one. That's how I learned that a microphone and speaker are the same thing.

[@eyerollthereforeiam1709]

I love your opening gags, but THAT ONE IS THE BEST!!!

[@stevebailey325]

Im 65, but boy, that song brought back some great memories. From what i remember, i saw Rush about 3 times. 😅

[@eyerollthereforeiam1709]

@@stevebailey325 I'm not a big one for concerts, but I wish I had seen them at some point.

[@cougarhunter33]

@@eyerollthereforeiam1709Same. One of my chief regrets is not seeing them a few years before they retired when the were doing the Moving Pictures and Permanent Waves concerts

[@chihuahuaphil]

@@stevebailey325 Saw them 4 times, which is about 40 too few!

[@filmclipuk]

Quite! it's the Spirit ;-)

[@kr6dr]

Discovering the 1N34 Germanium diode at Radio Shack was the greatest thing in my young life. Crystal radio was so much easier without the cat whisker and potted diode.

[@tomweickmann6414]

Wow. Someone out there remembers Radio Shack. I practically lived there as a kid, using my evil genius 🤣 to build spy transmitters. Did you also read Poor Man's James Bond? Bet ya did.

[@enilenis]

I love old vacuum tube radios with large components. You can figure out what everything does, just by looking at it, with no schematics. The orange glow. The warming up of the circuits. Massive mechanical parts. Pure nostalgia.

[@briandawkins984]

If it doesn’t warm up, glow orange and produces heat it just ain’t steam radio😊

[@jp-um2fr]

England. What an excellent video. I built and did terrible things to crystal radios, some of which actually worked. With a roughly 200 ft aerial at 30 ft, I could even use an old extension loudspeaker. I learned more about the history of crystal radios, etc. watching your videos, than all the books I ever read. Well done that man, I'll put you up for a knighthood (but don't hold your breath).

[@DavidFerree54]

My older brother got a little crystal radio for Christmas when he was about 10 years old. It was in a little red rocket ship looking thing. He eventually took it apart and hooked up an antenna to it and was receiving AM signals from all over the country. Years later when he was 14 and I was 13 he had progressed in his electronics tinkering to the point that he used that same little crystal radio as the guts of a broadcast station in our room with a horizontal wire antenna on top of our house. We had a radio show every evening, with me playing records (single 45s) and talking. The kids at school the next day always gave me reviews on our shows. Later still he did things like going through a local computer manufacturer's dumpster to retrieve mistakes they had thrown away and building super computers out of the parts. He joined the Air Force at 17 and his job was repairing guided missile systems. All from getting a toy for Christmas.

[@Huskrrrr]

I had one of those Rocket Radios, too.

[@gregmark1688]

That box of flashcubes makes me kinda crazy, for some reason. I built my first crystal radio sometime around 1970. This is absolutely the best explanation of their operation I have ever heard.

[@misterpancakes]

Huh I remember seeing this in Masters of the Air the other day when they crafted one in a POW camp, great timing!

[@12Q46HPRN]

I came to the comments to mention the same thing and wondered if this video was a coincidence or not . . . .

[@megamcee]

@@12Q46HPRN yep, was just about to do the same

[@frankschuler2867]

Funny story. I built a crystal radio for a science fair project as a kid in the 80's...got a blue ribbon! I still remember being fascinated by the ability to build a radio with just a few components and some blocks covered with aluminum foil (you'd slide the blocks over one another to act as a variable capacitor). I still remember Dad having to visit multiple Radio Shack locations to find the right components. I wish I still had it. It was little more than a handful of wire stuck to a block of wood using thumbtacks to complete the junctions.

[@mattheide2775]

Great video.Ispent some time as a radio operator 30 years ago. With the right atmospheric conditions a 10kW AM radio signal can travel around the globe easily. That is why AM radio stations transmit directionally at night here in the US. I used to only have an AM radio in my car and I would tune into some stations from Cali and Texas for fun. That radio had an excellent analog tuner with very fine adjustment. It was a stock radio from a 73 VW bug😊

[@jsnsk101]

strange far off late night am stations were always fun on a drive waiting for them to announce their town

[@thevoiceharmonic]

I built my first in 1972 when I was 13 and then a proper kit 2 years later. I set up massive aerials on my farm, one 300 foot long. My father got a terrible fright one dark windy night when my aerial came out of the sky and took his hat off! I had 3 aerials of different lengths and had to incorporate a volume control. I climbed a lot of trees

[@briandawkins984]

My dad wouldn’t allow me to erect a long wire antenna for fear of a lightning strike.

[@user-pd5ot4zd4b]

Love it, Spirit of the Radio, Eh Canida?!. I'm glad crystal sets are having a bit of a moment again. Still remember by pals RadioHack 101 project kit back in the 70's and grounding to a radiator, wire in a tree, sharing the earpiece. Good times.

[@kensmith5694]

Yes, I am seeing a lot of youtube videos about making them. I even made video to try to help them out on the topic of the 1N34 diode that normally was used as the detector. You can't get real 1N34 diodes easily these days.

[@Woffy.]

Making the detector is the magical bit but as mentioned in the video there are a number of solutions one being carbon and razor blade or a salvaged point contact signal diode. Have fun. Best @@kensmith5694

[@briandawkins984]

I had a three transistor radio shack p box I listened to the fall of South Vietnam and the watergate scandal on VOA. Great stuff.

[@rog2224]

Just before and just after the Great War, my great uncle used to bike around places in the Lincolnshire Wolds to log propagation with a crystal set. He'd post off the logs to some magazine (when he told me, he was in his early 80s and no longer remembered the name of it), as part of a data collection initiative of how weather and time of year affected domestic and international radio.

[@souta95]

I know the ARRL did something collecting reports like that at one time, but I don't know if they had people in England sending in reports. The ARRL's magazine is still being published, it's called QST.

[@MikeinVirginia1]

I was in Cub Scouts in the early 60's, and I built one to get an Arrow Point (the symbol for completing an activity). I bought 100 feet of Belden hookup wire and ran an antenna in my back yard. It didn't work. Then I moved it to sit on our washing machine in the garage. I connected the ground to the cold water pipe. It worked! I was so impressed I later became an electrical engineer and worked in the radio industry. And it all started in Cub Scouts!

[@williamlyerly3114]

Received the Heathkit crystal radio kit in the 1950’s for Christmas. Lived in South Carolina - AM was predominant Father helped me build - was ~8yo. Great memory.

[@wutzerface77]

Loved this channel before but throw in a Rush reference... now you're God tier

[@UltimateSeduction]

Build my first short wave crystal receiver 45 years ago when I was 7,thanks for this! ❤

[@jamesslick4790]

In the 1970's I put together a crystal radio kit (from Radio Shack..Natch..) AND an AM transmitter (Also from RS.) Both worked, No great distances covered, but they were FUN. Been into radio of all kinds ever since!

[@jackmambawitsin]

You have a great teaching style. You explained the theory around that circuit in such a way my squishy brain actually understood it 😊 I can tell you love your work and it shows, thank you.

[@tamasmihaly1]

Look at whose channel is blowing up. Congrats my friend. You’re awesome.

[@JamesHalfHorse]

At an AM station I engineer for I occasionally do tricks like putting some headphones on someone, touch the jack with my finger sometimes touch a ground and you can hear the broadcast in a similar principle to how a crystal radio works. l can also hold a curly bulb near the tuning coil (matches the transmitter to the antenna) and it will blink along with the modulation. Visitors think it's neat. Former engineer and mentor has some radios from the 20s when they were still experimental in his collection. They are beautiful both in looks and design for their time. I can sit for hours and talk with him about a 75 year career in radio learning as much as I can and do whenever I can while I still can. The engineers and teachers like him that really know this stuff that were there through most of its important evolutions and really know the history are a rapidly dying breed.

[@Borsia]

I had a crystal radio as a child, around 1958, that looked like an egg with a knob on one end that you turned to tune, a wire with an alligator clip that I clipped to the steel frame of the bunkbed and a earpiece. I loved that thing and could get all of the local AM stations. Thanks for reminding me of it 🙂

[@y_x2]

Very complete description of all old technology. Thank you

[@Gr0g234]

I was literally watching your videos and then videos about crystal radios all week, this is freaking me tf out lol

[@bok..]

Your description of Semiconductors was very good!

[@ThomasGrillo]

Back in the early 70s, I had a crystal radio kit from Radio Shack. After assembling it, I was hearing an AM station through it's earphone. Very cool. Thanks for sharing this.

[@bellofbelmont]

In the late 1960's the "party line" (shared landline connection) to our farm was replaced by underground cable which left almost 2 kilometers of overhead, insulated, soft iron wire in an "L" shape unused. So I connected my crystal set! I could listen to 2GZ Orange NSW Australia from about 130km (80miles) away. :-) .. Jim Bell (Australia)

[@sovietunion8304]

That’s awesome

[@InvestigationsDepartment]

I find your radio related videos to be interesting and a good contribution to the youtube community. Thanks!

[@spaceshantynow1851]

Great explanations of how crystal radios work! Thank you!

[@hagen-p]

When I was 12 years old, German Yps-Extra Nr.1 came with a germanium diode detector receiver. I used it a lot for listening to Sci-Fi radio dramas. Good times, nice memories.

[@oconnorsean12]

My entire family loves your channel! Especially my 20 something children who are fascinated by the technology that I grew up with 😀

[@charlesdudek7713]

When I was in elementary school my older brother had made a crystal radio mounted in a cigar box. He showed it to me and after checking it out I made my own. I would regularly fall asleep at night listening to radio stations and I remember a feeling of satisfaction listening to stations on a radio I had made myself.

[@caseynimmo4440]

Wonderful explanation of the resonate tank circuit.

[@bobingridshaw5361]

An absolutely supurb description of early equipment and theory of operation! Thank you!

[@hookeaires6637]

My first radio as a kid in the 60’s was a crystal set. Built it myself (grandfather helped). It was magic.

[@Jeremyak]

That's really cool they can be powered by the radio signal itself, it reminds me of "the thing" which was a soviet listening device that was activated by a directed radio signal which made it nearly impossible to locate with standard bug sweeping technologies. The very definition of elegant design.

[@NephilBlade]

Something this simple "wows" me more than the more complex things. To get something that works with so few components is amazing.

[@imark7777777]

Both videos still stand well on their own this was a nice update.

[@ricdintino9502]

Nice intro. I first saw Rush in 1977, likely before you were born.

[@elkneto4334]

man gilles so cool that your channel took off, so well deserved, such aweseome videos, greetings

[@_c_y_p_3]

You are awesome. So seriously interesting. Amazing that people have evolved these ideas.

[@ok9nja741]

I've made one of these couple of years ago. It was fascinating to build this very simple receiver with like 5 parts and then actually hear it work.

[@marknesselhaus4376]

You nailed this video very nicely. I started building crystal radios since the 1960's and had a sizable collection of early 1920's sets. I have been a Ham ( wa4jat ) since 1974 and still enjoy building crystal radio circuits for the short wave bands.

[@brivaneijm]

Thank you for sharing! This was a very informative video.

[@tseckwr3783]

Great video and history on radio. Thanks.

[@jimpalmer1969]

My parents bought me a crystal radio similar to the rocket ship radio at the 1962 World's Fair in Seattle. I went on to build other crystal sets including the foxhole radio using a blue raiser blade. When my son was in the Cub Scouts I out together a project for the boys where they built a crystal radio set on a board. I found a forum on line for crystal radios. The guys on the forum were so generous they mailed me the ear pieces, geranium diodes and variable capacitors needed so each boy had their own set. Pass it on.

[@Valery0p5]

Such a simple and elegant device. I didn't know about the variable capacitor models!

[@ronjones4069]

What a great explanation! I learned so much in spite of my 60 years of working with radio circuits. Thank you for this lesson.

[@jerryocrow1]

Fantastic presentation. Simple, basic, understandable, and for kids today, a look into the past. WOW.

[@AdvantestInc]

Fascinating deep dive into the history and impact of crystal radios on communication technology!

[@0dbm]

Excellent, thank you for your presentation, I really enjoyed it

[@earthoid]

Great detailed and historical video! You brought back memories of me in the 1950"s moving a cat whisker over a crystal and then being amazed at picking up a radio station.

[@tissuepaper9962]

You're a very brave man to speak about amateur radio and semiconductor physics on KZbin. There are lots of experts around just *dying* to correct miniscule mistakes and criticize simplifications made for clarity to a lay audience. Good video.

[@sparky6086]

20 years ago, a guy I knew bought a couple of mysterious boxes from an estate sale for nearly nothing, as no one knew what they were. They featured electrical terminals & knobs, but he couldn't figure out where a battery or other power supply hooked up, much less figure out what they were, or what they were supposed to do? He knew, that I was good at figuring things out, so he asked me. They were a couple of ready made crystal radio sets, which resembled if not identical to the Ariel one featured in the video. He was a technical person, who'd grown up making Radio Shack "Science Fair" kits & working on cars, so he knew about crystal radio sets, but had always thought of them as homemade, & never realized, that they were once a commercial product, placed in an attractive wooden cabinet! History books had always depicted crystal sets as diy contraptions.

[@uvman6648]

Of course I'm going to subscribe! Excellent description of crystal radio technology. Thank you for producing this wonderful video.

[@thatwontwork9046]

Your visuals are great!!

[@joewoodchuck3824]

I was building these in the 1950's. Led to a great career. Always a hobby as well to this day.

[@Erintel]

THANK YOU FOR THE HISTORICAL TUTORIAL. WHAT A GIFT OF NATURE! UNDERSTOOD AND ENABLED BY CLEVER PEOPLE, SHRINKING THE WORLD. EXCELLENT EDUCATIONAL APPROACH.

[@tfrowlett8752]

I loved your video on practice bombs, I was lucky enough to find an 8.5lb Mk2 practice bomb in an antique store

[@alastairchestnutt6416]

Great presentation. Thanks

[@jjmcrosbie]

Thank you for a clear and educational video. I live in France. France no longer has medium wave AM radio transmissions, so I was unable to test the crystal set which I had made for my grandson in Perth, Australia. He should get good reception as he lives just 7km from a 50kW transmitter! Like some other responders, I was given a crystal set when I was 12, in 1953. I eventually left school to study electrical engineering at university and ended my career as a head of a section of electronic engineers, having worked my way through the various levels of electronic engineering.

[@naughtiusmaximus830]

That was amazingly well done!

[@greggweber9967]

Very good refresher of some of my college electronics education from the early 1970s. You said something, and I knew that I knew what that word meant.

[@bradlevantis913]

Another excellent video. Thanks

[@superhawk1k382]

Thanks for this informative video - explained a lot as I’ve always liked listening to radio at night and listening to AM channels across the country (Skip was a listener‘a best friend)

[@old_guard2431]

Clear and comprehendible explanations, as we have come to expect and should not take for granted. The explanation of the difference between single and multi-strand conductors for AC is interesting. I always thought it was about flexibility, which would explain why the wiring for the main circuits in a house are single-strand while the connection wires for appliances, lamps, etc. are multi-strand. I assume the use of single strand wiring for main circuits is essentially a trade-off between economy and efficiency. With the price of copper these days, it seems like converting to multi-strand wires for mains might be worthwhile.

[@sharedknowledge6640]

Great video. I’m just old enough there were still crystal radio DIY kits available at Radio Shack and elsewhere when I was a kid despite battery powered transistor radios having been out for a long time.

[@bloguetronica]

Very informative! Thanks!

[@stuartchapman5171]

Built one from a kit, early 70's, loved it, started my passion for audio tech. Although an amateur, I've installed PA at Notting Hill Carnival, amongst countless parties, festivals, set up SW stations for sonic art projects, built and sold countless experimental fx, mixer, tape devices. I'd like to say it's kept me out of trouble, but I'm too honest, lol.

[@leifhietala8074]

That's a nice touch, a splash of "Spirit of Radio" to open things. What better intro?

[@davida1hiwaaynet]

Fascinating things. Thanks for sharing this!

[@ai4px]

I love the intros you've been doing..... Rush, spirit of radio. Pun intended.

[@kenbakker3241]

They are also Canadian, eh!

[@ai4px]

@@kenbakker3241 Did you know the way they came up with the name Canada? They started pulling letters out of a hat. First letter was "C", so the man pulling the letter says "C" eh. "N" eh. "D" eh. and a nation was born.

[@gristlevonraben]

great great video, i thank you guys for this!

[@lemonkey]

This was a really good explanation.

[@markdraper3469]

The little set I got in '63 from the Sunset House was egg shaped clear plastic on molded tripod feet. I was able to clip it to a ceiling light and got quite a few stations (it was L.A. of course) but the best reception came from KNX and KFAC.

[@umbrellacorp.]

I grew up in the 80's and 90's but I would of loved to live in those olden days 1920's. Life seemed so easy and comfortable back then.🥰👍💯

[@andrewmunz1639]

spectacular! thank you!

[@0MetallicaManX0]

That intro was so many kinds of satisfying 🤘

[@silvertube52]

As a boy I had a crystal radio. I lived in Michigan and loved that I could get stations from Chicago and New York.

[@pancudowny]

Looking at the Rocket Radio, it's easy to imaging a discreet pocket-sized crystal radio in the form of a fountain- or clip-style pen, with the wires being disguised as the strap/chain for a pair of eyeglasses/sunglasses.

[@midinotes]

Brilliant explanations of modern semiconductor diodes and tuned circuits. Fascinating to see these historic crystal sets, I've built a few over the years but these days it's getting increasingly difficult to find germanium diodes and crystal earpieces. Coupled with the fact there are fewer transmissions now on AM, unfortunately it's becoming less relevant to youngsters of today.

[@Mylestech-AU7]

I find it quite fun to build Crystal radios and radios in general your profile picture for this channel I still happen to have that exact tube

[@hallucinati]

That was awesome 👌 Thanks! 😊

[@chronobot2001]

Excellent video. I had a spy pen radio like the ones advertised in the old comic books as a kid. It worked great.... But that was when I lived in the city. I've tried to recreate it since with no success. I think the reason is because I live in a rural area now. I had no idea the detection range was so limited. Thanks for the video.

[@ibrahimkocaalioglu]

Well done. Hope you reach 100k subscribers soon. 👍

[@DiddleWithCare]

As a kid I had a crystal radio kit from Radio Shack. My dad strung a 1000ft wire between the house and a barn, terminating in my bedroom. I could pick up overseas stations, well, crystal clear.