Inside the 'Gibson Girl' Survival Radio

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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' ...
*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:
www.radiomanual.info/schemi/Su...
www.radiomanual.info/schemi/Su...
www.wftw.nl/gibsongirl.html

[@stevemcnaughton-kb3jc96]

I was a radioman on a destroyer back in the 70s and I was the one trained on the Gibson Girl. I believe it was left over from WW2. It came in a canvas bag which was padded with some kind of fiberous material, which leaked out all over the place. We had a balloon and a canister which would generate hydrogen gas when submerged in the sea. We all hoped we never had to use it, we doubted the ballon would even fill up. Thanks for bringing back some memories.

[@NickWeissMusic]

“Jennings! Where is our balloon and hydrogen canister?” “We used it at your birthday party, SIR!” “Ah yes, that was very thoughtful.”

[@richbuilds_com]

First thing that struck me when you opened it was: Everything is so *tidy*. Obviously been put together by people who a) knew what they were doing and b) cared about what they were doing

[@davidgold5961]

These were built to aircraft specifications.

[@williamromine5715]

I am 82, and have no electronics back ground. Therefore, I didn't understand anything you said, except you cannot crank it too fast. That's no big deal, however, because I learned that there were some pretty smart people back then to produce such a portable life saver that could survive a ditching into the ocean. Pretty amazing.

[@MostlyPennyCat]

It's pretty simple stuff, if I may. The two oscillators, audio and radio. Where it talks about "L"s and "C"s and then being "tuned". An L is a coil, a C is a capacitor. But, all you need to know is that they are the equivalent of a weight on a spring. It'll bounce at the speed it wants to, it's _tuned_ frequency. For the audio oscillator, it's tuned to go beep. For the radio oscillator it's tuned to make a radio signal. Amplifiers: A Tube is an amplifier. It takes a small signal and makes it bigger. Like putting your thumb over a hosepipe, small movements of the thumb (the audio input) shapes the flow of the water, specifically making it a powerful _copy_ of your thumb signal. So first you amplify the audio signal (beep), then you amplify the radio signal and _then_ you feed the two into _another amplifier_ (this last part is called modulation) So now you have a loud radio signal, modulated to go beep. Finally, there's the morse key. This disconnects the audio signal (shapeless, just goes beeeeeeeeeeeeeeeeep) It's just a switch, like a light switch. So now you can make your radio go dit dit dit dah dah dah dit dit dit (SOS) Any questions? 😁

[@jagmarc]

That techy info in the video is just for radio enthusiasts, to use one you wouldn't had needed to know all the techy diode-doubling plate relay oscillations killohertzing whatnots, just know how to work it as simple as possible. It's made inside just like an aircraft black box flight recorder, just as rugged and dependable

[@MichaelJohnson-tw7dq]

The only thing I don’t understand is, where do you stack the net after you get the fish onboard?

[@MostlyPennyCat]

Yeah, but it's fun to learn. Also it's fun to teach complex stuff with understandable analogies. And audio/radio electronics is almost always explainable with a weight on a spring and a thumb over a hosepipe. 😁

[@johanmetreus1268]

@@jagmarc As an automation technician, I resent being called a radio enthusiast just because I find videos like this highly entertaining ;-p

[@prestongivens3594]

As I recall, you’ve said that you don’t use a teleprompter. If that is true, and you did this from memory, I will give a big round of applause! Rattling off the circuit descriptions like you did takes a tremendous feat of memory, especially if you have not worked with tube circuits for many years. Bravo once again!

[@rorytaylor3761]

Nearly 60 years ago as a child of 9 or 10 I found the the cast-aluminium front panel of one of these in a junk pile in a quarry, “somewhere in England”, and took it home to add to my collection of interesting stuff. All of the electronics was missing but the ground wire and antenna were present. Particularly prized was the little bag of silica gel, which I used for “experiments”. I can’t recall what happened to it but during a subsequent lifetime working in electronics I realised it was probably a search and rescue item because of the yellow paint. And now because of this video, I know the full story! Thank you.

[@jagmarc]

One of the best things about this channel is the sound quality is great without thst massive oversized microphone taking up a third of the screen

[@lorraineq169]

Looks like it could be something like a Sony ECM77.

[@colinsmith458]

Sounds like actually having a lapel for the lapel Mic does wonders for sound quality!

[@jagmarc]

Spoken voice needs sweetening by some natural ambient room reverberation or it sounds dead and sterile. You can tell a professional sound engineers by the way they place mic, away a little bit, to capture just the right amount of room so there's no need to add artificial reverb

[@mightaswellbe]

Twenty years of flying around in a P-3 Orion and we carried one of these Gibson Girl radios. One of the crew was tasked with getting it out of the airplane if we ditched or attach the static line and toss it out the door in a bailout. It came packaged such that it would float and also had a parachute for bailout.

[@PaulLoveless-Cincinnati]

I should like to point out that you look quite dapper. Secondly, as a licensed ham radio operator - I am impressed at your level of RF knowledge.

[@jp-um2fr]

What a smashing video. I knew there were emergency radio transmitters around, but I never imagined they would be so sophisticated and well-built. Thank-you.

[@FlinFarmer]

I have known of the Winnipeg Aircraft museum for years and decided a couple weeks ago to go with a couple female friends. We were all amazed at how much was on display and recommend this as a top 10 places to see if interested in history. As a ham radio guy I found the Gibson Girl interesting and this video gave me the how does it work that I needed.

[@M3talhead2]

Old designs just look so much more better

[@bill-2018]

I remember seeing a Gibson Girl at the long gone Belle Vue Radio Rally, mid 1970's onwards. I didn't have a clue what it was but remember the colour and shape as it's very distinctive. What a great design. G4GHB.

[@Woffy.]

CQ G4GHB DE G8WOF..... Ahhhh the old Belle Vue Rally. Loads of goodies and huge glass insulators which made my antenna installation look more capable than it was. 73's K

[@bill-2018]

@@Woffy. I was G8JJC for 2 - 3 years. Always wanted c.w. and use it mostly. 73, G4GHB.

[@Woffy.]

C.W. a very civilised mode, me RTTY. 73's@@bill-2018

[@bill-2018]

@@Woffy. I've never tried RTTY, although years ago looked at the Creed RTTY stuff. Amazing mechanical equipment. 73, G4GHB.

[@Woffy.]

I had three Creeds getting the Tass, Reuters and AP news. My Dad would sit with a beer on Sunday so he would have the news before his colleagues. Still have several but not run for years. This chap has a great style of presentation, so fluid. 73's @@bill-2018

[@user-gs6lp9ko1c]

My Dad was in the US Navy in WW II, then called back up for Korea, and had a good story about his assignment as a radio tech on a fleet oiler (~30 man crew) off of Korea. One day he decided to test the ship's emergency 500 KC (no Khz in those days) transmitter. He did so at the proper time, and received the proper reply from Japan. As he was shutting down, the ship's cook came in and asked him to look at the cook's personal radio receiver, which just died mysteriously. My Dad noticed the cook had connected the receiver's antenna to the emergency transmitter's antenna. Dad fixed the radio, and from then on he was welcome into the galley anytime day or (especially) night, and given a snack of fresh eggs or whatever. Dad never told the cook what happened because, as he put it, if the snacks dried up, he would have to test the radio again.

[@johnmckee7937]

I'm a 70 yr dinosaur worked in communications all my life. Nice video

[@Woffy.]

A chum of mine got one of these from Super Radio in L-Pool, we had no idea what it was and as young lads didn't have the courage to open it because at that time (Cold War) a lot of Nuclear test gear was about and we thought it may contain ' Magic moonbeams '. Great presentation and you brought back some good memories.

[@souta95]

Videos like this bring the hams out of hiding 😅

[@Woffy.]

I am not here.

[@ShainAndrews]

Mmmmm Steamed Hams...

[@Steve-GM0HUU]

😂

[@pedrodepacas-ic1cb]

​@@ShainAndrews Seymour!!!

[@P_RO_]

dah dah didah di dah dit dah dah didit

[@scratchdog2216]

Paid $75 about 25yrs ago for mine. Still works. Wish we had a day like Grimeton to run these things.

[@Woffy.]

17.2 kHz ?. Grimeton, now that is a proper windup transmitter.

[@scratchdog2216]

@@Woffy. Well like a 500KHz day. Spark-gap day. IDK some time where we could play with these things is what I was thinking about. Obviously impractical but fun topic to kick around.

[@CathodeRayNipplez]

Intro's just keep getting more 440Hz bizarre and better every upload. 😆 Love this channel. 🤗

[@JohnnyWednesday]

I'm suspicious that this channel might be a secret art project. If he announces an experimental synth album this year? it'll make total sense

[@CathodeRayNipplez]

@@JohnnyWednesday 🤣

[@mackfisher4487]

I love the World War II era boat anchors having used both the transmitters and receivers in earlier days. I particularly enjoy the mechanical engineering of laying out of components necessary for the circuitry, the methodical repairable engineering behind them. When at the Air Force Museum's the engineering is so difference due to the state-of-the-art at that time. Thanks for your well-done presentation.

[@JohnLeePettimoreIII]

#BigClive needs to get his paws on this.

[@Woffy.]

Let the blue smoke out. He has done opened up a couple of Exp...ders.

[@Bartok_J]

Big Clive is scared of anything higher than 60Hz. ;-)

[@pinrouter]

The 12SC7 is a twin triode, not a double diode. A twin triode has two identical sections while a double triode has two dissimilar sections.

[@stevebailey325]

I was a Marine radar repairman in early 80s. Thstill taught us tube theory and i kinda follow along with your circuit explanations. 😊 i absolutely love you channel and am finally seeing you get the subs you deserve!

[@AdamosDad]

I saw one sitting in the corner of a transmitter space, aboard ship, back in the sixties. Thanks for the memory.

[@svgalene465]

I’m an amateur radio operator and I have a transceiver at arms reach, so I immediately tuned it to 8.364 MHz. Nobody is using their Gibson Girl transmitter within range.

[@ReggieArford]

Are those frequencies still used & available for search and rescue?

[@svgalene465]

I don’t know if they’re officially designated as S&R frequencies but, in an emergency, you are allowed use any frequency.@@ReggieArford

[@P_RO_]

@@ReggieArford Though still on lists and charts, there are no more radio distress frequencies; it's all been switched to satellites. The personal units are now pocket-sized, aircraft and ship units somewhat larger and automatic.

[@MichiganPeatMoss]

Well done on the rundown! So much thought put into their design, but then again, motivation is high during war efforts.

[@christophermarshall5765]

The crystal oscillator you speak of is a variant of the Colpitts oscillator. Three types of this exist. First one, using vacuum tube, second one, using solid state devices, & third one using a crystal.

[@stephenwalters9891]

The 12SC7 is a metal enveloped double triode and not a double diode, as you said. G7VFY

[@brucebuckeye]

Interesting, as always! Glad you gave a shout out to Mr Horn. You've got a great assistant there!

[@MaxPivovarov]

A very clever solution is to use a standard dynamotor as a two voltage generator.

[@extylerm]

Super cool, I had never seen one before, but I get why it's called the Gibson "Girl" with an hourglass shape like that.

[@roberts1938]

I am interested in military radios and I have seen these radios many times, but they seemed uninteresting to me. Now, after this episode, I see how wrong I was. These are very well-designed devices. I wonder what planes they were mounted on as rescue equipment? In one fragment you can see two pilots, so I assume that they were not only on the lifeboats of ships, but also in planes, maybe larger ones, but I am not sure.

[@wjodf8067]

Wonderful explanation that old rugged wiring of military stuff was a joy to rip apart and salvage parts thani you for the niceset video series on you tube

[@KeritechElectronics]

An interesting and extremely well built transmitter. It's a surprise that it doesn't have any receiving circuits - not even a crystal/diode detector and a headphone jack. I love the die-cast aluminum case with wells for antenna and ground wires - keeps things together all the time, stays waterproof. Nowadays it would be considered a horrendously expensive excess by the industry, and a thing of beauty and a joy for ever by nerds like us.

[@P_RO_]

Incorporating a receiver would have made it heavier, a lot more complex, and more costly. As any old-time Ham would tell you CW (morse code) transmitters are simple and easy, good receivers are not. Crystal sets need a strong signal to work which would be absent in the middle of an ocean. 500kHz was a world military and civilian standard distress frequency with people always monitoring for a call worldwide, so odds were great that someone would hear you thus no receiver was necessary. The other frequencies were military standards. It has all been switched to satellites now and there are no more international radio distress frequencies so this set would be ineffective today.

[@tylerkimble715]

We are going to need compilation videos of your awsome intros from time to time. They rock and stand alone well, as entertainment in there own right. Kinda like a short comic.

[@thisissoeasy]

incredibly interesting documentation! Thank you and, cheers from outback Australia!

[@MichaelCowden]

Love your videos, Jim! Thank you so much for all your research and no nonsense explanations, as well as great audio and video production and graphics and animations. Looking forward to more!

[@imark7777777]

That was an interesting deep dive.

[@ghsfdl4350]

IM glad you are working on your set. Old background was too distracting. You are getting there.

[@ibrahimkocaalioglu]

Good job. Thank you.

[@alexandermcalpine]

Well done! Great post.

[@Allan_aka_RocKITEman]

Great video, Gilles...👍

[@jamesrodrigues7391]

Nice piece.

[@TomKappeln]

GOLD ! Thank you

[@jeffreyyoung4104]

And now, the aircraft are equipt with automatic transmitters that can communicate with the GPS satellites and provide exact location to the search and rescue parties.

[@DavidLee-nd2sx]

That coffee looked piss weak. 😁. two more spoons and let it brew. That's just me though. You do you. Love the channel, I learn new interesting things.

[@MaxPivovarov]

The indicator of tuning scheme with a directional divider that I expected to see in the first transmitter appears in the second one.

[@Steve-GM0HUU]

👍Thanks for video.

[@cherrybacon9790]

Nice video!!!! Though... I was waiting for you to add a small speaker to the LF in order for us to hear the real transmission...

[@graemezimmer604]

Was also expecting to hear a signal from a nearby receiver.

[@W4BIN]

He erred, C101 between the two sections of the audio oscillator tube sections is part of the feed forward of the signal path, not the grounded connection shown. He mentioned K201 (not shown) I think it is K101. (speed regulation) Ron W4BIN

[@jagmarc]

I'm pretty sure I saw one of these being used in a USAF training film for flight crew who have to ditch at sea

[@demizer1968]

Testing it out once a year was a highlight for us Radiomen aboard ship.

[@Steve-GM0HUU]

Read your comment and remembered being trained on a Marconi emergency radio at college many years ago. I think it might have been a Marconi Survivor (Clifford and Snell 610). There was some sort of planned maintenance. Cannot remember the details but I think you were supposed to crank it in some sort of test mode and check it set off the alarm receiver. I do remember thinking, hope I don't ever have to use one of these for real.

[@graemedavidson499]

I have a Marconi Salvita from a merchant navy vessel that’s like a heavy yellow barrel version of this!

[@canadaisdecent1635]

Would you ever consider doing a video on Soviet AI-2 medkits?

[@MostlyPennyCat]

That is the weirdest switch mode power supply I've ever seen. A _physical relay_ does the switching

[@jagmarc]

That's similar to the rpm speed regulator the tone generator for 1920s telephone exchange. Fluttering contact voltage regulator is also over 100 years ago used in motor vehicles until 60s

[@P_RO_]

Look into 'vibrator tubes' which were in car radios and converted DC to a form of AC which the radio circuits required.

[@jagmarc]

@@P_RO_ Those aluminum can things I remember those. Today there's a mosfet forward converter, to replace them, one example I saw used a PIC microcontroller to make the complementary drive with a few percent deadband.

[@usmcbrat2]

Interesting device. Thanks! I would have liked to hear just 1-2 brief use cases. Did it save anyone? Etc.

[@matisseenzer2383]

Cool! I wonder what the modern equivalents are?

[@praveenb9048]

The Gibson Girl : An electrical device that Airmen and Mariners could strap between their legs and crank-operate when stuck somewhere far from civilization.

[@xenia5101]

For an excellent film that shows it in action- check out Ernest Gann's Island in the Sky starring John Wayne. Great explanation and yes, I have been trained to use it.

[@cwtrain]

Is my sleep schedule ass or do you just upload precisely when I'm ready for it?

[@manitobaoutdoors7705]

Hey, wow this was a great video. Man , your channel is really cool. I'm a ham radio operator. What quality content, too bad this will never be huge----ppl are too busy with tweeting about taylor swift's new thing to talk about

[@andrejrockshox]

why dont you put a link to the first video in description?

[@truthsRsung]

Google's Closed Captioning considers the winding of a generator as "Applause." Machines work as well together as Humans.😢😂😢

[@artyzinn7725]

theoretically those transmitters still work and you could pick up the signal with an AM radio sat close to it, with the coil antennas at least exposed. should make an interesting video by itself or epilogue.

[@roland985]

I wonder if we'll see this in Masters of the Air, the TV show?

[@bradlevantis913]

The introduction 😂😂😂

[@nooneyouknow9399]

Real radios glow. Tubes rock.

[@Laundry_Hamper]

@0:41 I recognize that trick

[@tjtarget2690]

Notification Squad! :D

[@2degucitas]

Looks straight out of Fall Out Las Vegas.

[@BobSaget69]

Is there anything that prevented the enemy from using captured Gibson Girls to ambush rescue aircraft’s?

[@Surestick88]

I mean, honestly, it's a survival situation, we're gonna need coffee. The shoulder strap on the earlier model looks to be over engineered by a couple of orders of magnitude. I've seen less substantial vehicle tow straps.

[@HouseholdDog]

Pipboy aesthetics.

[@Subgunman]

Are these transmitters still being monitored ? Seems a bit out of date especially the frequencies used. Most modern E Transmitters worked on 121.5 MHz and more recently at 243 MHz. I keep seeing videos on this platform saying it is illegal to "crank this transmitter" exactly who monitors this old stuff?

[@P_RO_]

Transmitting on any frequency without proper licensing or official permission is illegal except in extreme emergencies, though certain low-power transmissions are allowed. 121.6MHz is a 'guard' frequency no longer used for emergency 'beacons' like this; all that has gone to satellites now. 243MHz was used by the US and other militaries; I don't know that status. 2182kHz was once used as a worldwide maritime distress frequency along with 500kHz but no more.

[@Muonium1]

Were any of these ever actually used to successfully rescue anyone?

[@P_RO_]

Yes, it saw lots of use in the Pacific theater of WW2 and probably elsewhere as well.

[@kingfish4575]

First! Love the channel! Keep up the great work!

[@islakkie]

Now you have to explain an kettle to the Americans 😂

[@rickyrico80]

Where the heck do you keep finding this glorious glorious garbage?

[@pazsion]

and no battery, yet it stays powered?

[@wearemany73]

Why ohh why would you plunge the coffee straight after the water went in?!?!?! 😩

[@bazzaar1869]

He called the first device a double diode when its a double triode.

[@souta95]

I caught that too... He also had the wrong designation for the power supply regulator relay, but that could be due to a schematic revision.

[@mysticmarble94]

fallout radio 😯

[@ArnoSchmidt70]

By the way: It was invented by the Germans. The US Version is just a copy.

[@Iowa599]

All that stuff but no mic or speakers!?! Damn…what good is a radio if it can't bump!

[@charlesurrea1451]

Using b-roll to pan across the face of the objects being described would be preferred to your hard cuts.

[@greggweber9967]

I hope that it didn't transmit.

[@daviddavidson2357]

At the start of the video? No antenna. If it managed to transmit anything at all you'd be lucky to pick it up from a few feet away.

[@CathodeRayNipplez]

@@ricko.4411 😁

[@P_RO_]

Those frequencies are no longer in use for emergencies, and a lot of the old radio gear has components which fail with age so odd are that none of these work now unless they've been refurbished.

[@kiereluurs1243]

Ehm, too much detail. I was only interested in functionality. Cut.

[@kob8634]

What??? "sub seek went" in place of "sub se qnt" How did this happen all of a sudden? How is it that ORDINARY WORDS are showing up everywhere with these ridiculous pronunciations -- so eff's weird that I have to catch myself sometimes, "What'd he day.. huh, wha??" The word "subsequent" has been around for CENTURIES and there's NEVER been a "seek" in the middle of it until about the year 2020 or so... why??? why? YOU are old enough to pronounce this correctly young man! Oh yeah, unsub'd... I don't need this in my life!

[@jeffdroog]

I hope you find peace some day lol

[@JohnnyWednesday]

Love from England : please see the word "Sequence" while imagining a planet that's larger than your house

[@FrancisE.Dec.Esquire]

uBlock Origin stops ads 100%

[@JohnSmith-fq3rg]

Don't forget sponsorblock to block included sponser breaks in youtube videos. The sooner youtubers go back to just random people making cool stuff for fun, not profit, the sooner youtube will be fun again.

[@CathodeRayNipplez]

@@JohnSmith-fq3rg This is a business not a fukin charity John. 🙄

[@JohnSmith-fq3rg]

@@CathodeRayNipplez No man, this is a hobby.

[@CathodeRayNipplez]

@@JohnSmith-fq3rg Your hobby. His business. Stop being a freeloading panhandler.

[@VikingTeddy]

For now :/