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a video suggestion id love to see is different techniques to make these type of ac hook ups safer. ie. converting to a 3 prong chassis ground plug. ive looked around and have found very little info on this. love your content i learn so much.
So back in the day when they didn't have polarized plugs and connected two pieces of equipment together how did they know it was safe. I.E. connecting the output of a phonograph to this device here. Since the audio cable jacket is tied to the case on both ends if the power cable is flipped on one of the devices then you have a short between equipment. So how did the general public person with no knowledge of electronics keep from frying things.
Another Knight Kit from my youth! I seem to remember "accidentally" connecting one of those up to my 40 metre long-line and...oh, never mind. I also used to drive my mother crazy when she was trying to listen to Arthur Godfrey and I would interject some German polka music from a 78 rpm shellac record. That must have been about 1959.
You rascal you. In 1969 my father and I took a vacation to California from Texas. I had added a rear speakers to the 64 Ford to the am radio. In the crack of the rear seat was a wire splice. Out of San Francisco with my uncle Buster we went to Lake Tahoe. (First time I ever saw a Hemi CUDA) Buster would be singing away and I would touch the wires together. Buster would say Bobby what's wrong with your radio, dad had a funny look I don't know it's never done that. I am still blessed with my father. And my dear Mother. One of my father's stories is farmtown Bangs Texas a gentleman had his own little station played music. No running water no electricity but they had a battery powered receiver. Dad heard Hank Williams seven encores the Grand Ole Opry. We still go back and visit the 300 Acre Farm.
@@radiorick4975 Great stories. We had Sears battery radio in the 1950s and up into the 1960s up in northern Wisconsin. My dad was a professional symphony musician, so no Hank Williams, but the news and Arthur Godfrey, Amos and Andy and Jack Benny. I got my education on that radio. it had an expensive 15 volt dry battery, as big as a cigar box. We also had no running water or electricity and only a pot-bellied wood stove. Life was good then, too.
Nice video. I would like to see you hook It up to a turntable or other source and then see how far it will broadcast into a real radio. I ran a similar device as a dorm radio station in college. Great fun!
@@auspicioustoot The American Radio Relay League is the formal organization and outreach program for Amateur Radio operators (Ham Radio) and electronics enthusiasts in general. The ARRL handbook is an indispensable guide to learn all about amateur radio and electronics. You can find out more at www.arrl.org/
WOW. I built this unit in about 1959 0r early 60's. We had hours of fun tricking friends with their own car radios into believing the police were coming thru their AM radio's. While sitting out under the apple tree at a table we had hours of fun letting other neighborhood kids hear themselves on AM radio. Thank you Mr Carlson
I am loving this. My first kit. At age 10, I used this kit and was an imaginary DJ to my brother and two sisters. This was followed by a Knight Kit 101 experiments kit, Heathkit IM-13, helping my dad build a Heathkit Shawnee Six, trouble shooting a Collins R-388, then majoring in electrical engineering at Texas A&M. Followed by a career in media production and now as I near retirement I do high res audio engineering tracking, mixing and mastering of pipe organ and jazz performances. All starting with that cute little Knight Kit Broadcaster. 😀
Mr Carlson is well versed in all aspects of electronics including vacuum tube and solid state. He seems to have that natural ability to troubleshoot with both logic and gut feelings. He's probably one of the best electronic troubleshooters that I have ever seen. Bravo Mr Carlson..I love your videos!
MY MOM MAY HAVE MADE THAT 50C5. There was a factory in Norwood Ohio a few miles from here. She LOVED working with those little parts. I recall her telling me as a child and we actually spoke of it a few years ago. She died in April 2017 I have a few little ones around here somewhere. I built my own aprox 300W AM transmitter from parts of schematics from an ARRL handbook in the local library. I used a special order crystal in an army surplus oven, cut for 1610 AM from Jans Crystals, Crystal springs FL. I'm thinking I paid about $10 for that. The rest including Color TV horiz output tubes for the transmitter, x 4 Those were the days, I had a Heath Kit scope to watch the modulation. I was VERY popular around my neighborhood. for about 14 months... I was a bad boy.
m AUSTIN , hope you didn't get in trouble. 😀 Back in the 1960s, a friend of mine did that for about a month. He got a visit from two gentlemen from the FCC, who showed him the "error of his ways." 😀😀😀 Fortunately, he got off only with a warning.
@@jeromewysocki8809 Thank you sir. No I didn't get into trouble. I was about 13 when I started. Ran for 14 months. It was known that they didn't prosecute kids for this. I got a stern speech, made to dissemble the transmitter and they took my crystal. I had a spare but never went on again. That WOULD land you in prison. Not sure how much power. I had 4 x I think 6LQ6 big tube for horiz output with a cap on top for the plate voltage. I only ran about 40% modulation because my audio amp was only about 100w. That was 50 something years ago. The FCC guy was nice. He said they had me on a tracking station near Akron, OH. Had I paid attention in school, I'd have known that Akron is not near Dayton, about 50 miles but near Lake Erie south of Cleveland. My head would have been even bigger. Thanks, the good old days.
Used in series they can be used to access the minimum 10 dimensions proposed in string theory, but for satisfactory operation a power source of 3 G watts is required.
My friend built one in1964 and still broadcasts from it ! OMG, I can still remember his license: "Broadcast amplifier 83Y706 meets the FCC restricted radiation requirements under rule 15.204. Wow, how can I remember that?
It would have been interesting to see the RF waveform as well and see the strength of the RF harmonics. The clean AF suggest that this would be an excellent AM music broadcaster for your vintage radios.
I would like to see a solid state version available in the AM and FM band so that you could play your favorite music from an iphone in your car radio as well as antique radios.
@@audiobuff77 they exist. I've used one. They transmit on FM, but they only get crackle if you're near a transmitter physically, they're otherwise very effective
Paul, I had one of these, back in 1965. I ran a wire, out my bedroom window to my neighbors tree, about 120 feet away. I would load up my 45 record player, with records, and play it into this transmitter for hours, after school. My best friend lived about 5-blocks away, and he would dial it in! Then, one day, it just wouldn’t light up. Stuck it in a box, and mom chucked it, when I was in the USMC. Alas, it was fun while it lasted!
@jimpowell9205 - Semper Fi bro and Merry Christmas! I go back to the good old Radio Shack days, project kits 150 in one etc. My late father, an electronics engineer for USAF 30 years always got me into these type kits etc. Lots of memories with this stuff! To bad your mother tossed it in the garbage. Thanks for your story and service! Semper Fi USMC '75 - '81 OoohRah!
OMG I had this exact transmitter when i was a kid! We got it at a garage sale. I remember the seller saying "oh , oh thats trouble" picking on me for wanting it at 10 years old
@@ricande nope lol we lived 40 acres in the middle of nowhere. But that transmitter worked great. Dont remember what ended up happening to it. Maybe still at my parents house
Believe me your mother threw that “junk” away when you were away in the ( fill in the blank). Military College First out of town job Your own entry here…
We have cut the cable cord many years ago. These days I spend my tv time watching TH-cam videos. This is one subscription I look forward to new videos. Not an electronic guy at all I just enjoy his projects. I will leave watching Grays Anatomy and or any other net work gibberish to others to watch. I will pop my popcorn and watch Mr. Carlson’s Lab.
@@robertcalkjr.8325 Every episode of How the Universe Works and A Spacetime Odyssey is available for free without ads on ihavenotv.com along with 400 other full length astronomy documentaries, including from the Science channel and a lot of other channels, plus 2500 more on all kinds of other subjects. Did you know there was a research study which showed that children who were shown just two TV ads - and were then asked to choose between spending time with either a mean bully with the toy from the ads, or a nice friendly kid without the toy - invariably chose the bully with the toy?
Alden Zenko No, but I don't believe every "study" that I hear about. I don't want to wear my computer out on TV shows. Also, most of the time I DVR shows and skip past commercials or just mute them if I am watching live. I love remote controls!
I love the design of this. If you switch the 50C5s for 35C5s, you can drop in a 35W4 as a substitute for the selenium diode for an all-tube design with the still-working filament string. Can anyone offer information on winding an oscillator coil like that, regarding turn ratio and dimensions? I want to build one of these transmitters.
Augustin Chenault , yes, I would like to see that, too. Perhaps someone can quickly count the number of turns on each coil, and estimate the coil form outside diameter. It should be easy to duplicate the coil, then.
At the age of 5 years in 1965 I build my first own AM radio, a crystal detector with bed as antenna and heating as ground, works nice. Here in germany I never heard about this cool kit for to build your own Radio Broadcaster from 1959. With 1 tube in Meißner circuit I reach about 1 km distance via AM. Now, here sadly here is no AM at all. Would be interesting, to find all the parts Knight Radio Broadcaster And Amplifier (mostly tubes) for to rebuild this device, Dietmar
I built one of these in my early teens. My friends and I had no end of fun with this... Antenna length limitations? That meant to us put on a few hundred feet lol
Hahaha, of course! Must have been neat! I would have broadcast something to my friends up the street :) when I was young I found my grandpa's tube CB radio and I equipped my friends with truck cb's on power adapters so we could talk while we were supposed to be doing homework and not out playing.
My parents lived across the street from a park, had my buddy go over there with a portable radio and I would interrupt a song for a fake news report radio KNOW in the know with radio KNOW. I hadn't thought about that since forever
Within the limitations, AKA how much wire you had for the antenna, 10' or 500' the only limitation that I had was how much I wanted to rewind the antenna on to the spool. early in my life I built one of these from the similar kits out there, I was in a hurry and it didn't work. An old time radio guy fixed it, and it worked great.
My brother and I had this unit for our radio stations when we were kids (1965-1972). We hooked up the antenna output to a 20 foot piece of 12 gauge wire and went off to see how far it transmitted. We walked about a mile or two; the signal had drifted over onto a major station so we high-tailed it back and turned it off! Great device and great show today!!
Wow, you guys did just what I did and I think it was the very same year of 1965 when I had my own radio station each afternoon after school. the call letters were WNUT. It was lots of fun getting my classmates to try and tune in.
Maybe you could explain briefly the aging processes in Se rectifiers? Other parts could be good too - I know apout caps, vacuum tubes... What about resistors, transformers - oil-filled and other types, their "iron" parts? Ferrite too?
I wish there were new kits around like that, nowdays… I'd really much more prefer AM than FM. But that would be only fun in the US. Here in Germany running a low power radio station is pretty much impossible… unless it's just a weak little FM transmitter like those for cars >_>
Sir, would you consider covering selenium rectifiers more in depth? How are they made? What causes them to go bad? What are the symptoms of a failing selenium rectifier? What happens when they completely fail? (I heard it's bad) And how to replace a selenium rectifier with a modern silicone diode while at the same time maintaining the proper output voltage of the circuit. Thank you for your outstanding content.
I'd also love to learn more about them. I have a couple of old ones that I've played around with, and I know they do age and apparently smell horrible when they burn up. I built a "vintage parts only" ~12V power supply from a 6.3V filament transformer and a Se bridge rectifier operating as a voltage doubler, and it made just enough power to plug in a 12V car USB adapter and charge a phone. I even used authentic '60s Cornell-Dubilier electrolytics for the filter cans!
At 40:00 did anyone else think of the "Outer Limits" theme? "There is nothing wrong with your television, do not attempt to adjust the picture............" Another great video Mr C. Wish I knew a small percent of what you do!
I was always interested in electronics. Went to college in 1989 initially to get an AS in electronics. Unfortunately i'm not THAT Mathletic and flunked out. Also, the teachers sucked. They were old at the end of their career and just didn't give a crap. They also couldn't teach in a way that showed you application. I went back for Computer aided design and several years later went back again for plastics. But electronics was always dear to me. 35 years after wanting a Ham radio license I studied and tested directly to General a couple weeks ago. The simple electrical theory rekindled my interest in it. Seeing these videos it's the first time in a long time that things make sense. If I had a teacher like you I probably would have hung with it and had a very different career.
I was surprised to see your scope showing the demodulated signal and not the RF envelope. Old AM guy here. I'm used to watching envelopes. BTW, I'm so old that whenever I see an N-channel FET I imagine it as a triode. 😊 Another well done, informative video. Thanks and 73!
Can't blame you for that. From a teaching / understanding electronics perspective the inner workings of tubes are easier to understand than unipolar or bipolar transistors and for some applications tubes are having near-perfect properties, all good for getting started. What I don't like about tubes, in particular power tubes are the voltages in the kilovolt range near the knuckles while doing adjustments or heat that puts a sauna to the shame ...
@@ralfbaechle Yes, semiconductors take some teaching. But once you understand the theory about how a semiconductor works, it is no more difficult to learn about transistors than it is to learn about valves.
you got it. i was going to say the same. clearly a switch, no actuator means relay minus coil. and it doesn't look bimetallic, so it's not a thermal switch.
No, not thermal. I think the actuation is either by by bending a membrane at the bottom to move the central lever, or by a magnetic field from a solenoid extending into the vacuum part.
@@ariedemuijnck i've had the type you speak of with the actuator at the bottom (used to have one that i got at a hamfest once). if it's one of those, it's of a different type than the one i had. i'm still thinking he's showing a relay without the coil. the distances between the elements is rather large too, guessing decently high voltage 5-10kV?
We built a high school "rock radio" station (studio) and fed one of these Knight broadcasters way up in an attic space, near the roof - had about a 1 mile radius in reception. Big dreams back in the 60's !
Hi, Paul! Love the videos! I worked in the electronics, radio and TV trade all my life (now retired), so I can identify with pretty much everything. One thing I would ask: when you talk about vacuum tubes ('valves' in the UK), would it be possible to mention the European equivalents, if known? For example, 12AX7 = ECC83. They are more familiar to us the other side of the Pond. Keep up the excellent work! ...Jim
i know literally nothing bout this stuff, i just like to watch! Thank you sir!, please produce more content! Great video quality and audio quality! - From everyone who doesnt know what this stuff is but finds it interesting!
In a previous video you mentioned that one of your Christmas habit is to transmit classic Christmas carols to your old radios. I really find that awesome actually. You also mentioned that you will make a vid on how to build a small signal AM transmitter (obviously tube operated) for our self, to do the same thing. I'm really really (really) waiting for that one... At first I thought this will be it. So still looking forward for that! Btw great vid again!
That device you were holding is a vacuum switch or relay. It is perfect for antenna switching, high voltage switching, or isolating because it has very low capacitive coupling.
love your videos so so much!!! i learn a ton and with every vid i always learn so so much from you. again tytytyty . Me and my dad watch your vids all the time. im only 13 and my father is 36 and he makes me get off my phone lol ugh! but i am greatful for him showing me electronics. never thought in a million yrs that it takes so much so much when it comes to all this. i love math and now falling in love with electronic designs and the great minds that invented such works of art. P.S. its made me open my mind to learning more and more math, science, and a very good thought of maybe future E.E. when i finally finish highschool. still seems so far away :(
james Crews , good for you! My father did the same with me when I was your age. (I'm 71, now, and still cherish the fun I had learning this stuff, then.) I'm doing the same with my grand children. They LOVE it!
james Crews , forgot to add this to my comment. We didn't have TH-cam when I was your age. My father gave me all the junk radios and televisions that his customers at his repair shop discarded (because they were too expensive to repair). Under his direction, I built all kinds of neat stuff with the discarded parts. Not everything worked at first, but I learned a lot and had good fun doing so.
Keep up your interest and learning, James! I was about your age when I started fiddling with stuff & taking things apart. I got my first Ham license at age 15...and when I was all of 19, I was recruited by Martin Marietta & was an Electronics Engineering Development Technician who helped design some new electronics for the Space Shuttle! I made my living as an Electronics Tech & STILL have fun with my Ham station! My Grandson is almost 13 (on 2 FEB 20) & he already has an interest in radio & electronics. Whatever you do....HAVE FUN, young man!
Yep, That was the “rig” Dad & I built for my youthful local radio station, albeit I added a long wire, which, as I mentioned in a comment on your post about your Gates Broadcast Xmtr, brought an FCC van cruising my neighborhood, in search of my errant unlicensed station. Knightkits & Heathkits put together on the kitchen table were my electronics “schooling” leading up to ham radio, TV repair, Bourns BioMed bench tech, arcade game tech, then EMI/RFI open field lab test tech with the advent of pc & mainframe computer hardware. An even more beautiful pix of your amazingly organized electronic Garden of Eden-out of camera range, of course, is a workbench covered with caps, resistors, half-breadboarded projects buried in a rat’s nest of spaghetti, smeared with rosin drips & burn marks as the smoke of a well used Weller Station wafts over it all...oh, sorry, I was looking at mine! 73’s, WB6U
Wow - I remember every detail from age 9 when it was a brand new kit; I wish I had kept it. ( I built TWO of them! Worked, but I never could get the range to go beyond a few houses. RF was a complete mystery to me as I experimented with various antenna "wires" and overworked that slot on the tuning capacitor. Unsupervised 110 VAC construction by a kid... good old days! lol)
I have not built a tube type, but I did build a Crystal receiver with the old bare crystal and cat whisker and about 150 feet of antennae with my dad when I was about 9 and it worked! but I think we were smarter back then, kids now days they would have the "stick the wire in your butt and plug it in challenge" HAHAHA
@@kenseastrand7428 YES! I'm happy to hear that (back then) you found the exact sweet spot in that bare crystal. A "modern" germanium glass diode did not produce the same thrill for the next generation... And today, it's got a touch screen.
Illegal maybe but widely practiced years ago & even today. You can easily hack those little mp3 player FM transmitters to send a signal much further than intended! I've tried it myself!
Super glad this vid came across my feed. Total newbie here but just picked up 2-3 garage projects to start learning on very recently. Thanks and Subbed!...
I built one of these as a kid. I do remember the last part of the instructions where it says to attach the supplied wire to point X and said "this is your antenna DO NOT EXTEND this wire!" Needles to say the first thing I did was attach to my 100 foot longwire shortwave receive antenna and the second thing I did was walk around several blocks around the neighborhood listening for the signal (I ran a tape recorder into it). Went several blocks, and I learned how to couple the little pocket transistor radio to a telephone pole to bring it in.
Like the batterytester 93 years old, old stuff really works nice and better, with higher tolerances than today's electronics that barely works with very low tolerance so that it breaks quickly, more often buying of shitty stuff and manufactorers make more money. Good video.
I had one when I was a teenager! I am 73 now! My twin brother and I hooked up a long wire antenna and tested the range with a portable radio and were able to get 5 blocks in the neighborhood!!!
Me too and me too, etc. One way to get all the geezers out of the wood work! I would play Al Hirt on mine. I agree Mr. C should have hooked up some music and used a vintage radio to listen to it. I don’t remember it being AC/DC or getting a bite from it. I’ll point out the 2 meg grid resistors which allowed the small coupling caps and still have good bass and was grid leak biased. The 12ax7 are also grounded cathode to get the most gain. 2 47k resistors we’re all that stood between us and line voltage. Thanks for the blast from the past!
I built one of those as my first kit. I used it as an audio amp with a turntable and speaker . It played my mono Beach Boy albums an an acceptable level and sounded good. I replaced it with a Heathkit stereo vacuum tube amp which served me well. Of course I had no idea it was so dangerous, but everything probably was back then. I still have the albums.
Excellent video as usual! And of course EXCELLENT CHANNEL! One of my FAVORITES! This video, and so many others like it are great, but they always assume a fair amount of knowledge and experience from the start. That’s fine and dandy, BUT, let’s face it: WE WERE ALL BEGINNERS AT ONE TIME. I still have a TON to learn myself. That said, SO MANY videos and TH-camrs like this TALK about safety, but never actually SHOW the safety procedures. Yeah, yeah, I know: If you don’t have experience working with this stuff, you shouldn’t be doing it. But let’s face it: Nine out of ten REALLY GOOD technicians on TH-cam, AND IN THE REAL WORLD, are SELF TAUGHT. I took correspondence courses from the Cleveland Institute of Electronics 30 years ago, but it was all theory, almost no hands on, and we all know that the learning doesn’t RRREALLY start until we roll up our sleeves and STICK OUR HANDS INSIDE. These self-taught, now-EXPERTS, are people that INDEED stuck their hands in places and at times they shouldn’t have. How about making some videos, or just appending an extra five minutes to future videos ACTUALLY SHOWING THE DISCHARGING PROCESS; actually SHOWING the do’s and don’ts of SAFETY. MOST TH-cam channels like this show scene cuts AFTER something has ALREADY been done (this channel included): New scene: “Ok, now you can see that I have replaced all the caps.”.... NNNNO!!! SHOW yourself replacing the caps! SHOW yourself discharging the unit before sticking your hands in there. SHOW yourself taking measurements, and SHOW beginners that lethal voltages REALLY ARE present BEFORE any discharging takes place. If you do this, you will foster a LOT more education, and especially, A LOT MORE SAFETY. In short, show, SHOW, SSSHHHOOOWWW! ... Or just like the song by Canadian band, Rush, says, “SHOW ME, DON’T TELL ME!”... Great video, great channel, and I am a faithful viewer, follower, and fan, but SHOW rather than just tell! Thanks!
My dad bought me one of these about 60 years ago. Both of us put it together. Had lots of fun with it. BTW, here is a picture of me with it. It was $12.95 plus postage. ($112 today) makearadio.com/transmitters/images/knight-kit-dave.jpg The photo is from my homemade radios site. That device looks like a rotary vacuum switch relay.
Ah, this brings back memories of when I fired up my own AM broadcast station as a teen long ago. Via surplus and for about $5, I'd gotten the LF oscillator accessory that was installed in some WWII ART-13s. It was intended to let that Collins-made HF aircraft transmitter tune down the ship frequencies below the AM broadcast band. Since it tuned into the low end of the broadcast band, that gave me an idea. For modulation, I took an audio output transformer that converted from a high impedance (tube) to a speaker (low). I reversed it, feeding the low impedance speaker output of my SW radio into it and feeding the power for the oscillator through the high impedance winding. For an antenna, I hooked up both sides of the coax feeding my 10-meter beam, so that meant about a 20-foot high vertical. Oh, and I hooked a high-voltage capacitor from a TV between the plate of that oscillator and the antenna, so the antenna wouldn't be hot with about 250 volts. Since this wasn't exactly to FCC regulations, I took two precautions. First, I put it on the air on Christmas Day. Surely, I told myself, they won't be working today. And second, for audio I supplied it with what a local AM station was broadcasting. If anyone tuned it in, they'd wonder why that station was on a different frequency. Then I took off in the family car to see how far I was getting. On one direction, a dry, sandy hill top, it petered out after about five blocks. In the other, with damp soil, it was still strong when I got to a wood almost a mile away. That way, it was probably getting about two miles. Here's what I was using: ----- Low Frequency Coverage and More Accessories - The standard ART-13 transmitter frequency range is from 2.0mc to 18.0mc, however many Navy ATC and T-47/ART-13 transmitters and later USAAF T-47A/ART-13A transmitters were equipped with a plug-in Low Frequency Oscillator (LFO) module that allowed the transmitter to operate from 200kc to 600kc or 200kc to 1500kc (at somewhat reduced power, CW only for electrically short antennae.) Early LFOs had a frequency range of 200kc to 1500kc in six ranges designated as O-16/ART-13, while the later LFOs cover 200kc to 600kc in three ranges and is designated as O-17/ART-13A. The LFO modules used a single 1625 tube. When the LFO is in operation the ART-13 Multiplier section is bypassed and the LFO output directly drives the PA. --- The ART-13 was probably the most beautifully made of the WWII transmitters, as you can see from the interior photos here. www.radioblvd.com/art13.htm
I took my 1961 Knight Kit Broadcaster mobile one time. Using one of my friend's dad's shaver inverter, plugged into the cigarette lighter of the ole 1949 Chevy, and the car radio antenna disconnected and hooked to the Broadcaster. My friend could hear me about a mile away, as I remember (a relatively open area). Bet that little inverter was huffing and puffing and I can't remember if it survived the test.
As a kid in the 1950's I worked and experimented with various electronic devices such as this, was shocked numerous times and never experienced issues. Is there any evidence that people were actually killed by these devices other than having them thrown in a bath while someone was in the tub?
Boy that brings back memories. Built one in the 50s. Had my own radio station in my neighborhood. I'm 73 now. Was talking to one of my neighbors who I hadn't seen for 60 years the other day and she asked me if I remembered being a DJ back then. Amazing this pops up on my internet coincidentally.
I made an AM transmitter for my grade 8 science project, the design was from Howard Sam's "Having fun with Transistors". It used 2 2n107 germanium transistors and I had to wind my own antenna coil. It had a range of 6 feet and appeared on 7 different points on the tuner dial.
Seems to me it's easier to build modulation circuits with tubes than with Transistors/FETS. It's like they give you more options, like the screen, to modulate with. What type of oscillator is that last tube working as? Would you say that 47K resistor going to the audio section could be a form of decoupling as well?
Back in the day, Stancor and Triad were the big dogs on the street for transformers and could easily run up to 1/2 the cost of the kits or more, so line voltage design, while "tasty", allowed a fairly affordable build for the hobbyist kid- like I was. My best friend and I would head to the dump about once a month and harvest components from old t.v.'s and radios we dug up for our reuse. Once we took a bucket of tubes to the local supermarket that had one of those courtesy tube testers there, but we were thrown out after about a half- hour of using their electricity and not buying any of their tubes. ☺ Damn, those were fun times for a coupla entrepreneurs!
The thing that always confused me about valves/vacuum tubes... is the fact that north america and europe used totally different designations for the same tube. Same thing still happens today in other sectors... but I like the explanation of the North American designation system... 12 ax 7 being 7 useful elements in the tube... clever!
Lafayette Radio made these AM broadcasters also--and in fully built form. They continuously but slowly would drift off frequency--even after being on for 5 or 6 hours--requiring listeners to retune every 15 minutes or so. But for $5, the broadcasters still were a good deal and lots of fun.
Thx Mr. Carlson ! Your explanations are both clear and concise and entertaining often ! I wish I had decided to become an instructor years ago as I think I would have followed your lead. My instructors were quite dry most of the time and thus quelled most of my original desire to learn electronics as originally intended. I look forward to following your coursework. The materials of CREI were my original material obtained and it was quite good. They were sold to another company and quickly went downhill , dang shame as many followed them at the time.
I'm going to be building a little transmitter with a 1Zh37b rod pentode once I get all of the parts ready. These unique Soviet subminiature tubes use closely spaced rods rather than grids and have unusually good low-voltage performance.
lmao, butter knife and torch. when i was like 7 years old and i started taking my first electronic stuff apart all i had was a butter knife and the stove top. i still have a faint scar on my wrist from where i was trying to resoldier a pair of headphones and slipped and laid the end of the redhot end of it on there. later on, i begged my dad for an iron after that.
I used a piece of copper, i think it was a copper nail, tied to a piece of thick wire (no idea what it was, but you couldn't bend it with your hands). But still on the stove top :) i guess, a lot of us start there.
Growing up near Chicago was always torn in my locality between Knight kit and Heath kit. My first kit was a Knight VTVM, saved up all summer 1961 between 8th grade and freshman high school.
My brother and I had something very similar to this back in the 70's. It was a 7 or 9watt AM broadcast amp. We would broadcast our radio station WAMAMFM through out our neighborhood. I'll never forget the fun we had. Sometimes my brother would walk up to Mr. Doughnuts at the end of our street to buy cigarettes from the vending machine there for 45¢ and he'd have his transistor radio with him to check our signal strength while I would broadcast. I'd broadcast what kind of doughnut I'd want him to bring home and would have to promise over the air to pay him back. It was sooo cool when he brought home the right flavor doughnut.
I never knew there were that many young guys like me that loved to “experiment” making our own broadcast stations. Later on I bought an FM kit and supposedly it had a limited range. I was able to pump out a signal for about a half mile or so. Didn’t have a PLL so the signal would drift. But it was fun.
Another really interesting video of yours, and I appreciate it's not intended to be a high-spec device, but could we have a bit more technical analysis of it please? What was the maximum undistorted modulation depth? And min and max modulation frequencies at the 6dB points? How many mV required at the input for maximum modulation? Was there a significant amount of FMing on the simple AM transmitter circuit - particularly as modulation is applied to an L/C oscillator? How much does it drift from switch-on? With the recommended antenna, what is the approximate range using an average radio for reception? What was the frequency coverage? Was it the full AM band or just a section? In your opinion is it worth any of us sourcing the parts and building a reproduction of this vintage design - despite the obvious safety issues? Thanks.
It is of course illegal to create radio transmissions without a licence in the Uk, be they commercial or amateur. apart from certain radio bands such as CB Radio (27 Mhz) and 315MHz, 433MHz, 868MHz, 915MHz and 2.4GHz
If that kit was available in the UK the chassis would have to be earthed (grounded), especially as it is a transformer-less circuit. Thinking about it, it would have a mains transformer to improve safety and use 6.3 volt heater (filament) valves (tubes). The UK and Europe have 240 volts mains, so dropping the filament voltage would be less easy.
I know Mr Carlson is being deadly serious when he says "You're doing so at your own risk".... but I still chuckle every time. It's like his signature tagline. It wouldn't be a proper Mr Carlson video without it. Imagine if he uses that line in his day to day life. Like he wakes up and makes coffee, and hands a cup to his wife. "If you're drinking coffee with me, you're doing so at your own risk." ... Then he takes his kids to school... "If you're getting less than A's in math, you're doing so at your own risk." ... Then he goes to work... "If you're collating those documents, you're doing so at your own risk." ... Then he comes home and the wife calls, saying she'll be late and to please go pick up her mother at the airport. He replies... "If you're asking me to go pick up my mother in law, you're doing so at your own risk." His tone is especially calm and neutral for this one, sending shivers up the wife's spine. ... I'm just joking around, but High Voltage is no joke. Don't play with it unless you know what you're doing. Keep one hand in your pocket at all times, and remember... you're following along at your own risk!
Mr. Carlson, Dating myself here but, When I was a kid back i'm guessing in the mid 50's or so. Myself and a couple friends used to order stuff from Allied radio all the time. Transistors were I believe about .99 cents each, We built transistor radios with 2 or 3 transistors in them (that was fancy stuff at the time) Anyway one of us bought and built that kit, I believe they called it a wireless oscillator at the time. I lived about 1 mile away from Paul (he's the one that had it). When I left Paul's house I could hear him till I got almost all the way home.
Ok, I'll be the gumby to say it. Mr Carlson looks like a very young version of the doc. This is really episode 4 where he's stuck in 2020 and misses his childhood transmitter. And, yes the radios RF output is 1.21GW.
Years ago, I built a Ramsey FM stereo radio transmitter. I didn't know what to expect but the Ramsey transmitter can transmit a high fidelity stereo signal about a half mile with the small antenna that comes with the kit. You could probably transmit a better signal with a better external antenna but I have never tried it.
Great video. As a kid I built a Radio Shack low power AM transmitter and adjusted the tuning up to the TV channels so I could jam the video of our own TV. We had only one TV and if I jammed the channel my sisters wanted then I would get to watch something better on another channel ! Worked great but eventually I got caught. I guess it became obvious finally as after an argument over what channel was going to be watched I would run upstairs and tune the transmitter until I heard screams of displeasure downstairs 😂.
Omg, I built one of these when I was 12. 1958? How cool to see it again. I used it to re-transmit my favorite FM jazz station (KRHM) so I could listen to Miles Davis out in the backyard. Man was I a hepcat kid or what? 😂. Thanks so much Mr. Carlson!
Hi Paul, I would like to ask why you don't use nano-farad? You say 0.0047uF or 4700pF, but we normally use 4.7nF. In the past, multiples of nF were not really used much, but today they are commonly used.
I could really see myself using this in my teens. I used a really crude Walkie talkie setup and for longer transmissions a mobile. This was when Mercury released a free 6pm-6am tariff. Man I was wondering what the blue & black device was doing, displaying random numbers. Then I realised it was my phone's voltage.
I learned the hard way about no Isolation when I was a teenager I tried hooking up a ground on a tube radio and when I touched the ground to the chassis, KER_POW!!!!, ARCED and blew the house fuse! Luckily the wire I used was insulated.
I wanna see one for shortwave radio. I’d set up a hifer radio beacon at 13.565.000 MHz under fcc part 15 lol. Hifer is the acronym for high frequency experimental radio.
An interesting video. I had not heard of this device. In my ham career I've played around with Knight Kit transmitters. AM radio, hmmm I may or may not have "accidentally" warped the tuning of my Viking Valiant's 160 Meter vfo into the top end of the broadcast band.
Omg all the oscopes around you.. can I buy one.?they all look like 70"s to 70s models. Kudos on an amazing video I will now subscribe..I have just found your vids . Btw can this be used with an FCC license?
Wow did that bring back memories. That was the first transmitter I ever had. I put it in a wooden box and modified it to also be an intercom. I somehow lost the unit over the years but it was the beginnings of my lifelong carrier in TV, Radio and Microwave broadcast RF engineering. Thank you Knight Kit and Mr., C
This episode sure brings back memories! I built many Knight-kits (and Heath-kits) in ages past. I didn't build this particular one, but some of my contemporaries copied the schematic, added an RF amp stage, and began broadcasting AM radio, playing 45 rpm records. The signal carried several miles, but had to be retuned when someone accidentally bumped the counter!
Boy is that thing dangerous, I usually avoid anything without a transformer. Even if you got the plug in the right way, when you turned off it's power switch, which is in the neutral side, everything is going to float up to 120V, lovely. I once saw a design for the ultimate in dangerous NiCad battery chargers, it had a light bulb, a diode, and the battery holder strung directly across the mains! They did recommend putting it in a box with a lid switch to isolate things when you opened the lid........
I still have my Knightkit Broadcaster. I built it around 1961. Three of us in our neighborhood used them to "ham" with. I also used it for a guitar amplifier. And I subsequently got my Ham license....56 years now.
A relay, actuated by the effect of a magnetic field developed by the current in its energizing coil(s). There used to be 4 manufacturers who built this device, now there are still 3 offering it to the market. Originally, this device was used by the military (like many of those things). BTW, Paul, next time please hide the part number on the device. This one was easy to read and google offered the answer right away. :)
Are you feeling all right Mr Carlson because this must be the first time ever that old capacitors have not met the Carlson's lab bin of death...........I thought the weird valve thing was some sort of training aid but I know I am wrong!!......Great video .:)
Wow - I went back to my own little example. Replaced C-7, the 470pf - I had no suitable mono caps, so I used a 470pf silver-mica. It's as stable as the transistor radio I'm using to 'preview' it. It used to drift for about 20 minutes before it warmed up. Thanks!
Hm. I've been trying to build a gilbert cell in ltspice and studying the superhet again. I just learned earlier today the definition of "heterodyning" as a verb(Weird we never discussed it as that term in my communications class), so I actually knew what you meant when you said that. Fancy coincidence.
Items such as what you presented here, can be found at Ham radios swap meets. I like to pick up such items as they probably do not work, and see if I can make them work. Some of my favorites are Heathkits of all kind, as these items where all built by someone, and the manuals for them can usually be found on the Internet. I like the simple kits, as they are fun and easy for me to trouble shoot and they maybe useful in my Ham radio. Thanks again for a great job of explaining how all of this "old stuff" works!
You might have restored it and compared its "new" specs with the old ones... commenting on the change. A frequency plot of the transmitted audio would have helped, also... to show that "small is also useful." I owned one back in the early 60's and used it at a boy's camp for fun. I also taught amateur radio and was a swimming instructor as well as having a cabin full of kids.
I had the Ramsey Am Broadcast TX kit, fun to build and use for my local neighbors, they liked listening to me every evening. Miss the closure of Ramsey Kits!
Mr Carlson, I am not an engineer nor do I know anything about electronics. I simply enjoy watching your content. You are so intelligent. I learn new words every video. Haha. 43 and still learning and entertained. Thanks
Paul, I've watched this video a couple times now and this time the came to me, " Why doesn't Mr. Carlson build a AM broadcaster like this ... only better" and post it to Patreon!
Mr Carlson, have you tried to back feed audio through the secondary of the audio transformer from another amplifier? As I recall from my youth, that will improve the audio quality of the Knight broadcaster.
To learn electronics in a different and effective way, and also get access to my personal electronic designs and inventions, click here: www.patreon.com/MrCarlsonsLab
a video suggestion id love to see is different techniques to make these type of ac hook ups safer. ie. converting to a 3 prong chassis ground plug. ive looked around and have found very little info on this. love your content i learn so much.
@@xcreeperify i agree that would be highly useable!!!
I love your videos! I just became a patreon this morning. keep up the good work!
So back in the day when they didn't have polarized plugs and connected two pieces of equipment together how did they know it was safe. I.E. connecting the output of a phonograph to this device here. Since the audio cable jacket is tied to the case on both ends if the power cable is flipped on one of the devices then you have a short between equipment. So how did the general public person with no knowledge of electronics keep from frying things.
Excellent audio quality!
Remember, all real radios glow in the dark.
And so do the people who still use them
Well I just used a radioactive dildo and now my ass is glowing.I guess radioactive stuff makes us glow once we use it.
Yessir
Go Radium!
Another Knight Kit from my youth! I seem to remember "accidentally" connecting one of those up to my 40 metre long-line and...oh, never mind. I also used to drive my mother crazy when she was trying to listen to Arthur Godfrey and I would interject some German polka music from a 78 rpm shellac record. That must have been about 1959.
Also metal clothes lines make great (and long) antennas ;D
@@BillAnt LOL!!
You rascal you. In 1969 my father and I took a vacation to California from Texas. I had added a rear speakers to the 64 Ford to the am radio. In the crack of the rear seat was a wire splice. Out of San Francisco with my uncle Buster we went to Lake Tahoe. (First time I ever saw a Hemi CUDA) Buster would be singing away and I would touch the wires together. Buster would say Bobby what's wrong with your radio, dad had a funny look I don't know it's never done that. I am still blessed with my father. And my dear Mother. One of my father's stories is farmtown Bangs Texas a gentleman had his own little station played music. No running water no electricity but they had a battery powered receiver. Dad heard Hank Williams seven encores the Grand Ole Opry. We still go back and visit the 300 Acre Farm.
@@radiorick4975 Great stories. We had Sears battery radio in the 1950s and up into the 1960s up in northern Wisconsin. My dad was a professional symphony musician, so no Hank Williams, but the news and Arthur Godfrey, Amos and Andy and Jack Benny. I got my education on that radio. it had an expensive 15 volt dry battery, as big as a cigar box. We also had no running water or electricity and only a pot-bellied wood stove. Life was good then, too.
Nice video. I would like to see you hook
It up to a turntable or other source and then see how far it will broadcast into a real radio. I ran a similar device as a dorm radio station in college. Great fun!
Oh Thank God! A Breathe of Sanity in the Waves of Bullshittery! You Sir Rock!
right
Yah, I am so sick of what is played on stations today.
Dude, you're the living ARRL handbook! Great video and fun teardown!
Lance Emil MY GOD YOU’RE RIGHT! He’s 🖖!
What’s that?
@@auspicioustoot The American Radio Relay League is the formal organization and outreach program for Amateur Radio operators (Ham Radio) and electronics enthusiasts in general. The ARRL handbook is an indispensable guide to learn all about amateur radio and electronics. You can find out more at www.arrl.org/
WOW. I built this unit in about 1959 0r early 60's. We had hours of fun tricking friends with their own car radios into believing the police were coming thru their AM radio's. While sitting out under the apple tree at a table we had hours of fun letting other neighborhood kids hear themselves on AM radio. Thank you Mr Carlson
I am loving this. My first kit. At age 10, I used this kit and was an imaginary DJ to my brother and two sisters. This was followed by a Knight Kit 101 experiments kit, Heathkit IM-13, helping my dad build a Heathkit Shawnee Six, trouble shooting a Collins R-388, then majoring in electrical engineering at Texas A&M. Followed by a career in media production and now as I near retirement I do high res audio engineering tracking, mixing and mastering of pipe organ and jazz performances. All starting with that cute little Knight Kit Broadcaster. 😀
Thanks for sharing your story Gordon!
Appointment today?
Mr Carlson is well versed in all aspects of electronics including vacuum tube and solid state. He seems to have that natural ability to troubleshoot with both logic and gut feelings. He's probably one of the best electronic troubleshooters that I have ever seen. Bravo Mr Carlson..I love your videos!
MY MOM MAY HAVE MADE THAT 50C5. There was a factory in Norwood Ohio a few miles from here. She LOVED working with those little parts. I recall her telling me as a child and we actually spoke of it a few years ago. She died in April 2017 I have a few little ones around here somewhere. I built my own aprox 300W AM transmitter from parts of schematics from an ARRL handbook in the local library. I used a special order crystal in an army surplus oven, cut for 1610 AM from Jans Crystals, Crystal springs FL. I'm thinking I paid about $10 for that. The rest including Color TV horiz output tubes for the transmitter, x 4 Those were the days, I had a Heath Kit scope to watch the modulation. I was VERY popular around my neighborhood. for about 14 months... I was a bad boy.
m AUSTIN , hope you didn't get in trouble. 😀 Back in the 1960s, a friend of mine did that for about a month. He got a visit from two gentlemen from the FCC, who showed him the "error of his ways." 😀😀😀 Fortunately, he got off only with a warning.
@@jeromewysocki8809 Thank you sir. No I didn't get into trouble. I was about 13 when I started. Ran for 14 months. It was known that they didn't prosecute kids for this. I got a stern speech, made to dissemble the transmitter and they took my crystal. I had a spare but never went on again. That WOULD land you in prison. Not sure how much power. I had 4 x I think 6LQ6 big tube for horiz output with a cap on top for the plate voltage. I only ran about 40% modulation because my audio amp was only about 100w. That was 50 something years ago. The FCC guy was nice. He said they had me on a tracking station near Akron, OH. Had I paid attention in school, I'd have known that Akron is not near Dayton, about 50 miles but near Lake Erie south of Cleveland. My head would have been even bigger. Thanks, the good old days.
Pretty sure that's a 6 way flux capacitor.
Used in series they can be used to access the minimum 10 dimensions proposed in string theory, but for satisfactory operation a power source of 3 G watts is required.
i was going for an arc relay ... and dont know any thing about most of what is talk about on this channel .... lol
My friend built one in1964 and still broadcasts from it ! OMG, I can still remember his license: "Broadcast amplifier 83Y706 meets the FCC restricted radiation requirements under rule 15.204. Wow, how can I remember that?
It would have been interesting to see the RF waveform as well and see the strength of the RF harmonics. The clean AF suggest that this would be an excellent AM music broadcaster for your vintage radios.
Yes, I was hoping to see the modulated RF carrier envelope to be able to assess symmetry of up/down modulation. Nice, entertaining video in any case.
I would like to see a solid state version available in the AM and FM band so that you could play your favorite music from an iphone in your car radio as well as antique radios.
@@audiobuff77 they exist. I've used one. They transmit on FM, but they only get crackle if you're near a transmitter physically, they're otherwise very effective
Paul, I had one of these, back in 1965. I ran a wire, out my bedroom window to my neighbors tree, about 120 feet away. I would load up my 45 record player, with records, and play it into this transmitter for hours, after school. My best friend lived about 5-blocks away, and he would dial it in! Then, one day, it just wouldn’t light up. Stuck it in a box, and mom chucked it, when I was in the USMC. Alas, it was fun while it lasted!
@jimpowell9205 - Semper Fi bro and Merry Christmas! I go back to the good old Radio Shack days, project kits 150 in one etc. My late father, an electronics engineer for USAF 30 years always got me into these type kits etc. Lots of memories with this stuff! To bad your mother tossed it in the garbage. Thanks for your story and service! Semper Fi USMC '75 - '81 OoohRah!
@@JohnPiperBoots I’m older………..67 - 71
OMG I had this exact transmitter when i was a kid! We got it at a garage sale. I remember the seller saying "oh , oh thats trouble" picking on me for wanting it at 10 years old
WELL??? What happened? You got in to trouble, didn't you? :)
@@ricande nope lol we lived 40 acres in the middle of nowhere. But that transmitter worked great. Dont remember what ended up happening to it. Maybe still at my parents house
Believe me your mother threw that “junk” away when you were away in the ( fill in the blank).
Military
College
First out of town job
Your own entry here…
@@josephpadula2283 My Mom would neatly line up shiny solder balls but stuff nasty ol' green circuit boards in the trash . . .
Great! I built the Graymark broadcaster kit in High School electrical shop in the early 70's. It used a pair of 50C5s and a 12AV6 if I remember.
We have cut the cable cord many years ago. These days I spend my tv time watching TH-cam videos. This is one subscription I look forward to new videos. Not an electronic guy at all I just enjoy his projects. I will leave watching Grays Anatomy and or any other net work gibberish to others to watch. I will pop my popcorn and watch Mr. Carlson’s Lab.
There are other stuff on cable, you know. I am multitasking and watching the Science channel right now about supernovas and other good stuff!
@@robertcalkjr.8325 Every episode of How the Universe Works and A Spacetime Odyssey is available for free without ads on ihavenotv.com along with 400 other full length astronomy documentaries, including from the Science channel and a lot of other channels, plus 2500 more on all kinds of other subjects.
Did you know there was a research study which showed that children who were shown just two TV ads - and were then asked to choose between spending time with either a mean bully with the toy from the ads, or a nice friendly kid without the toy - invariably chose the bully with the toy?
Alden Zenko No, but I don't believe every "study" that I hear about. I don't want to wear my computer out on TV shows. Also, most of the time I DVR shows and skip past commercials or just mute them if I am watching live. I love remote controls!
I love the design of this. If you switch the 50C5s for 35C5s, you can drop in a 35W4 as a substitute for the selenium diode for an all-tube design with the still-working filament string.
Can anyone offer information on winding an oscillator coil like that, regarding turn ratio and dimensions? I want to build one of these transmitters.
Augustin Chenault , yes, I would like to see that, too. Perhaps someone can quickly count the number of turns on each coil, and estimate the coil form outside diameter. It should be easy to duplicate the coil, then.
At the age of 5 years in 1965 I build my first own AM radio, a crystal detector with bed as antenna and heating as ground, works nice. Here in germany I never heard about this cool kit for to build your own Radio Broadcaster from 1959. With 1 tube in Meißner circuit I reach about 1 km distance via AM. Now, here sadly here is no AM at all. Would be interesting, to find all the parts Knight Radio Broadcaster And Amplifier (mostly tubes) for to rebuild this device,
Dietmar
I built one of these in my early teens. My friends and I had no end of fun with this... Antenna length limitations? That meant to us put on a few hundred feet lol
Hahaha, of course!
Must have been neat! I would have broadcast something to my friends up the street :) when I was young I found my grandpa's tube CB radio and I equipped my friends with truck cb's on power adapters so we could talk while we were supposed to be doing homework and not out playing.
My parents lived across the street from a park, had my buddy go over there with a portable radio and I would interrupt a song for a fake news report radio KNOW in the know with radio KNOW. I hadn't thought about that since forever
Within the limitations, AKA how much wire you had for the antenna, 10' or 500' the only limitation that I had was how much I wanted to rewind the antenna on to the spool. early in my life I built one of these from the similar kits out there, I was in a hurry and it didn't work. An old time radio guy fixed it, and it worked great.
My brother and I had this unit for our radio stations when we were kids (1965-1972). We hooked up the antenna output to a 20 foot piece of 12 gauge wire and went off to see how far it transmitted. We walked about a mile or two; the signal had drifted over onto a major station so we high-tailed it back and turned it off! Great device and great show today!!
Wow, you guys did just what I did and I think it was the very same year of 1965 when I had my own radio station each afternoon after school. the call letters were WNUT. It was lots of fun getting my classmates to try and tune in.
Maybe you could explain briefly the aging processes in Se rectifiers? Other parts could be good too - I know apout caps, vacuum tubes... What about resistors, transformers - oil-filled and other types, their "iron" parts? Ferrite too?
I wish there were new kits around like that, nowdays… I'd really much more prefer AM than FM. But that would be only fun in the US. Here in Germany running a low power radio station is pretty much impossible… unless it's just a weak little FM transmitter like those for cars >_>
Sir, would you consider covering selenium rectifiers more in depth? How are they made? What causes them to go bad? What are the symptoms of a failing selenium rectifier? What happens when they completely fail? (I heard it's bad) And how to replace a selenium rectifier with a modern silicone diode while at the same time maintaining the proper output voltage of the circuit. Thank you for your outstanding content.
I'd also love to learn more about them. I have a couple of old ones that I've played around with, and I know they do age and apparently smell horrible when they burn up. I built a "vintage parts only" ~12V power supply from a 6.3V filament transformer and a Se bridge rectifier operating as a voltage doubler, and it made just enough power to plug in a 12V car USB adapter and charge a phone. I even used authentic '60s Cornell-Dubilier electrolytics for the filter cans!
At 40:00 did anyone else think of the "Outer Limits" theme? "There is nothing wrong with your television, do not attempt to adjust the picture............" Another great video Mr C. Wish I knew a small percent of what you do!
Felt like ages mr. Carlson uploaded something. Great upload :)
I guess his project videos take a lot of time to put together because he's such a perfectionist. Always great to see a new upload
I was always interested in electronics. Went to college in 1989 initially to get an AS in electronics. Unfortunately i'm not THAT Mathletic and flunked out. Also, the teachers sucked. They were old at the end of their career and just didn't give a crap. They also couldn't teach in a way that showed you application. I went back for Computer aided design and several years later went back again for plastics. But electronics was always dear to me. 35 years after wanting a Ham radio license I studied and tested directly to General a couple weeks ago. The simple electrical theory rekindled my interest in it. Seeing these videos it's the first time in a long time that things make sense. If I had a teacher like you I probably would have hung with it and had a very different career.
I was surprised to see your scope showing the demodulated signal and not the RF envelope. Old AM guy here. I'm used to watching envelopes.
BTW, I'm so old that whenever I see an N-channel FET I imagine it as a triode. 😊
Another well done, informative video. Thanks and 73!
I tend to think of it more as a pentode (without the screen grid) because of the high drain resistance.
Can't blame you for that. From a teaching / understanding electronics perspective the inner workings of tubes are easier to understand than unipolar or bipolar transistors and for some applications tubes are having near-perfect properties, all good for getting started.
What I don't like about tubes, in particular power tubes are the voltages in the kilovolt range near the knuckles while doing adjustments or heat that puts a sauna to the shame ...
@@ralfbaechle Working around tubes does teach you to be careful. And to keep one hand in your pocket.
@@ralfbaechle Yes, semiconductors take some teaching. But once you understand the theory about how a semiconductor works, it is no more difficult to learn about transistors than it is to learn about valves.
That's a vacuum relay. Looks like a DPDT type. Movement though the base (membrane?). Solenoid is missing?
you got it. i was going to say the same. clearly a switch, no actuator means relay minus coil. and it doesn't look bimetallic, so it's not a thermal switch.
No, not thermal. I think the actuation is either by by bending a membrane at the bottom to move the central lever, or by a magnetic field from a solenoid extending into the vacuum part.
@@ariedemuijnck i've had the type you speak of with the actuator at the bottom (used to have one that i got at a hamfest once). if it's one of those, it's of a different type than the one i had.
i'm still thinking he's showing a relay without the coil. the distances between the elements is rather large too, guessing decently high voltage 5-10kV?
We built a high school "rock radio" station (studio) and fed one of these Knight broadcasters way up in an attic space, near the roof - had about a 1 mile radius in reception. Big dreams back in the 60's !
Doesn't matter how many times I see Mr. Carlson's equipment room I am always in awe
Free Saxon same
It looks like a frickin spaceship
Hi, Paul!
Love the videos! I worked in the electronics, radio and TV trade all my life (now retired), so I can identify with pretty much everything.
One thing I would ask: when you talk about vacuum tubes ('valves' in the UK), would it be possible to mention the European equivalents, if known? For example, 12AX7 = ECC83. They are more familiar to us the other side of the Pond.
Keep up the excellent work!
...Jim
i know literally nothing bout this stuff, i just like to watch! Thank you sir!, please produce more content! Great video quality and audio quality! - From everyone who doesnt know what this stuff is but finds it interesting!
Same here except I'm lost after positive and negative.
In a previous video you mentioned that one of your Christmas habit is to transmit classic Christmas carols to your old radios. I really find that awesome actually. You also mentioned that you will make a vid on how to build a small signal AM transmitter (obviously tube operated) for our self, to do the same thing. I'm really really (really) waiting for that one... At first I thought this will be it. So still looking forward for that! Btw great vid again!
Amen
That device you were holding is a vacuum switch or relay. It is perfect for antenna switching, high voltage switching, or isolating because it has very low capacitive coupling.
love your videos so so much!!! i learn a ton and with every vid i always learn so so much from you. again tytytyty . Me and my dad watch your vids all the time. im only 13 and my father is 36 and he makes me get off my phone lol ugh! but i am greatful for him showing me electronics. never thought in a million yrs that it takes so much so much when it comes to all this. i love math and now falling in love with electronic designs and the great minds that invented such works of art.
P.S. its made me open my mind to learning more and more math, science, and a very good thought of maybe future E.E. when i finally finish highschool. still seems so far away :(
james Crews , good for you! My father did the same with me when I was your age. (I'm 71, now, and still cherish the fun I had learning this stuff, then.) I'm doing the same with my grand children. They LOVE it!
james Crews , forgot to add this to my comment. We didn't have TH-cam when I was your age. My father gave me all the junk radios and televisions that his customers at his repair shop discarded (because they were too expensive to repair). Under his direction, I built all kinds of neat stuff with the discarded parts. Not everything worked at first, but I learned a lot and had good fun doing so.
Keep up your interest and learning, James! I was about your age when I started fiddling with stuff & taking things apart. I got my first Ham license at age 15...and when I was all of 19, I was recruited by Martin Marietta & was an Electronics Engineering Development Technician who helped design some new electronics for the Space Shuttle! I made my living as an Electronics Tech & STILL have fun with my Ham station! My Grandson is almost 13 (on 2 FEB 20) & he already has an interest in radio & electronics. Whatever you do....HAVE FUN, young man!
Zback in the 50s we were told to keep your left hand in your back pocket. While working on these. Ac dc radios.
Yep, That was the “rig” Dad & I built for my youthful local radio station, albeit I added a long wire, which, as I mentioned in a comment on your post about your Gates Broadcast Xmtr, brought an FCC van cruising my neighborhood, in search of my errant unlicensed station. Knightkits & Heathkits put together on the kitchen table were my electronics “schooling” leading up to ham radio, TV repair, Bourns BioMed bench tech, arcade game tech, then EMI/RFI open field lab test tech with the advent of pc & mainframe computer hardware.
An even more beautiful pix of your amazingly organized electronic Garden of Eden-out of camera range, of course, is a workbench covered with caps, resistors, half-breadboarded projects buried in a rat’s nest of spaghetti, smeared with rosin drips & burn marks as the smoke of a well used Weller Station wafts over it all...oh, sorry, I was looking at mine!
73’s, WB6U
Wow - I remember every detail from age 9 when it was a brand new kit; I wish I had kept it.
( I built TWO of them! Worked, but I never could get the range to go beyond a few houses. RF was
a complete mystery to me as I experimented with various antenna "wires" and overworked that
slot on the tuning capacitor. Unsupervised 110 VAC construction by a kid... good old days! lol)
I have not built a tube type, but I did build a Crystal receiver with the old bare crystal and cat whisker and about 150 feet of antennae with my dad when I was about 9 and it worked! but I think we were smarter back then, kids now days they would have the "stick the wire in your butt and plug it in challenge" HAHAHA
@@kenseastrand7428 YES! I'm happy to hear that (back then) you found the exact sweet spot in that bare crystal. A "modern" germanium glass diode did not produce the same thrill for the next generation... And today, it's got a touch screen.
A very interesting video. I wasn't aware that anyone could broadcast am in the USA. This is illegal in the Uk. Great video good to see you back.
Illegal maybe but widely practiced years ago & even today.
You can easily hack those little mp3 player FM transmitters to send a signal much further than intended! I've tried it myself!
Super glad this vid came across my feed.
Total newbie here but just picked up 2-3 garage projects to start learning on very recently.
Thanks and Subbed!...
I Still Have Mine From A Kit My Dad Built Back In 1965.
I built one of these as a kid. I do remember the last part of the instructions where it says to attach the supplied wire to point X and said "this is your antenna DO NOT EXTEND this wire!" Needles to say the first thing I did was attach to my 100 foot longwire shortwave receive antenna and the second thing I did was walk around several blocks around the neighborhood listening for the signal (I ran a tape recorder into it). Went several blocks, and I learned how to couple the little pocket transistor radio to a telephone pole to bring it in.
Like the batterytester 93 years old, old stuff really works nice and better, with higher tolerances than today's electronics that barely works with very low tolerance so that it breaks quickly, more often buying of shitty stuff and manufactorers make more money. Good video.
Great job .. haven't seen a Knight Radio Broadcaster And Amplifier since I was a kid. You covered a lot in 45 minutes!
My very first electronic kit when I was a kid in the 60's! Thank you so much for that nostalgic trip! Brings back a lot of memories!
Glad you enjoyed it Ken!
I had one when I was a teenager! I am 73 now! My twin brother and I hooked up a long wire antenna and tested the range with a portable radio and were able to get 5 blocks in the neighborhood!!!
Me too and me too, etc. One way to get all the geezers out of the wood work! I would play Al Hirt on mine. I agree Mr. C should have hooked up some music and used a vintage radio to listen to it. I don’t remember it being AC/DC or getting a bite from it. I’ll point out the 2 meg grid resistors which allowed the small coupling caps and still have good bass and was grid leak biased. The 12ax7 are also grounded cathode to get the most gain. 2 47k resistors we’re all that stood between us and line voltage. Thanks for the blast from the past!
I built one of those as my first kit. I used it as an audio amp with a turntable and speaker . It played my mono Beach Boy albums an an acceptable level and sounded good. I replaced it with a Heathkit stereo vacuum tube amp which served me well. Of course I had no idea it was so dangerous, but everything probably was back then. I still have the albums.
Excellent video as usual! And of course EXCELLENT CHANNEL! One of my FAVORITES! This video, and so many others like it are great, but they always assume a fair amount of knowledge and experience from the start. That’s fine and dandy, BUT, let’s face it: WE WERE ALL BEGINNERS AT ONE TIME. I still have a TON to learn myself. That said, SO MANY videos and TH-camrs like this TALK about safety, but never actually SHOW the safety procedures. Yeah, yeah, I know: If you don’t have experience working with this stuff, you shouldn’t be doing it. But let’s face it: Nine out of ten REALLY GOOD technicians on TH-cam, AND IN THE REAL WORLD, are SELF TAUGHT. I took correspondence courses from the Cleveland Institute of Electronics 30 years ago, but it was all theory, almost no hands on, and we all know that the learning doesn’t RRREALLY start until we roll up our sleeves and STICK OUR HANDS INSIDE. These self-taught, now-EXPERTS, are people that INDEED stuck their hands in places and at times they shouldn’t have. How about making some videos, or just appending an extra five minutes to future videos ACTUALLY SHOWING THE DISCHARGING PROCESS; actually SHOWING the do’s and don’ts of SAFETY. MOST TH-cam channels like this show scene cuts AFTER something has ALREADY been done (this channel included): New scene: “Ok, now you can see that I have replaced all the caps.”.... NNNNO!!! SHOW yourself replacing the caps! SHOW yourself discharging the unit before sticking your hands in there. SHOW yourself taking measurements, and SHOW beginners that lethal voltages REALLY ARE present BEFORE any discharging takes place. If you do this, you will foster a LOT more education, and especially, A LOT MORE SAFETY. In short, show, SHOW, SSSHHHOOOWWW! ... Or just like the song by Canadian band, Rush, says, “SHOW ME, DON’T TELL ME!”... Great video, great channel, and I am a faithful viewer, follower, and fan, but SHOW rather than just tell! Thanks!
My dad bought me one of these about 60 years ago. Both of us put it together. Had lots of fun with it. BTW, here is a picture of me with it. It was $12.95 plus postage. ($112 today)
makearadio.com/transmitters/images/knight-kit-dave.jpg
The photo is from my homemade radios site. That device looks like a rotary vacuum switch relay.
Thanks for sharing that photo Dave! You have a great site as well.
Ah, this brings back memories of when I fired up my own AM broadcast station as a teen long ago. Via surplus and for about $5, I'd gotten the LF oscillator accessory that was installed in some WWII ART-13s. It was intended to let that Collins-made HF aircraft transmitter tune down the ship frequencies below the AM broadcast band. Since it tuned into the low end of the broadcast band, that gave me an idea.
For modulation, I took an audio output transformer that converted from a high impedance (tube) to a speaker (low). I reversed it, feeding the low impedance speaker output of my SW radio into it and feeding the power for the oscillator through the high impedance winding. For an antenna, I hooked up both sides of the coax feeding my 10-meter beam, so that meant about a 20-foot high vertical. Oh, and I hooked a high-voltage capacitor from a TV between the plate of that oscillator and the antenna, so the antenna wouldn't be hot with about 250 volts.
Since this wasn't exactly to FCC regulations, I took two precautions. First, I put it on the air on Christmas Day. Surely, I told myself, they won't be working today. And second, for audio I supplied it with what a local AM station was broadcasting. If anyone tuned it in, they'd wonder why that station was on a different frequency.
Then I took off in the family car to see how far I was getting. On one direction, a dry, sandy hill top, it petered out after about five blocks. In the other, with damp soil, it was still strong when I got to a wood almost a mile away. That way, it was probably getting about two miles.
Here's what I was using:
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Low Frequency Coverage and More Accessories - The standard ART-13 transmitter frequency range is from 2.0mc to 18.0mc, however many Navy ATC and T-47/ART-13 transmitters and later USAAF T-47A/ART-13A transmitters were equipped with a plug-in Low Frequency Oscillator (LFO) module that allowed the transmitter to operate from 200kc to 600kc or 200kc to 1500kc (at somewhat reduced power, CW only for electrically short antennae.) Early LFOs had a frequency range of 200kc to 1500kc in six ranges designated as O-16/ART-13, while the later LFOs cover 200kc to 600kc in three ranges and is designated as O-17/ART-13A. The LFO modules used a single 1625 tube. When the LFO is in operation the ART-13 Multiplier section is bypassed and the LFO output directly drives the PA.
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The ART-13 was probably the most beautifully made of the WWII transmitters, as you can see from the interior photos here.
www.radioblvd.com/art13.htm
I took my 1961 Knight Kit Broadcaster mobile one time. Using one of my friend's dad's shaver inverter, plugged into the cigarette lighter of the ole 1949 Chevy, and the car radio antenna disconnected and hooked to the Broadcaster. My friend could hear me about a mile away, as I remember (a relatively open area). Bet that little inverter was huffing and puffing and I can't remember if it survived the test.
Thanks for sharing your story John, there sure have been some interesting entries here.
As a kid in the 1950's I worked and experimented with various electronic devices such as this, was shocked numerous times and never experienced issues. Is there any evidence that people were actually killed by these devices other than having them thrown in a bath while someone was in the tub?
nice find! elegant little circuit there, and at least the person who built it knew his ass from his elbows.
Boy that brings back memories. Built one in the 50s. Had my own radio station in my neighborhood. I'm 73 now. Was talking to one of my neighbors who I hadn't seen for 60 years the other day and she asked me if I remembered being a DJ back then. Amazing this pops up on my internet coincidentally.
I made an AM transmitter for my grade 8 science project, the design was from Howard Sam's "Having fun with Transistors". It used 2 2n107 germanium transistors and I had to wind my own antenna coil. It had a range of 6 feet and appeared on 7 different points on the tuner dial.
7 points simultaneously? Lots of harmonics..
Seems to me it's easier to build modulation circuits with tubes than with Transistors/FETS. It's like they give you more options, like the screen, to modulate with.
What type of oscillator is that last tube working as?
Would you say that 47K resistor going to the audio section could be a form of decoupling as well?
Back in the day, Stancor and Triad were the big dogs on the street for transformers and could easily run up to 1/2 the cost of the kits or more, so line voltage design, while "tasty", allowed a fairly affordable build for the hobbyist kid- like I was. My best friend and I would head to the dump about once a month and harvest components from old t.v.'s and radios we dug up for our reuse. Once we took a bucket of tubes to the local supermarket that had one of those courtesy tube testers there, but we were thrown out after about a half- hour of using their electricity and not buying any of their tubes. ☺
Damn, those were fun times for a coupla entrepreneurs!
The thing that always confused me about valves/vacuum tubes... is the fact that north america and europe used totally different designations for the same tube. Same thing still happens today in other sectors... but I like the explanation of the North American designation system... 12 ax 7 being 7 useful elements in the tube... clever!
Lafayette Radio made these AM broadcasters also--and in fully built form. They continuously but slowly would drift off frequency--even after being on for 5 or 6 hours--requiring listeners to retune every 15 minutes or so. But for $5, the broadcasters still were a good deal and lots of fun.
The mystery tube appears to be some type of vacuum switch or relay.
Id want to add a 50,000 watt linier amplifier, and start a guerilla radio station.
Thx Mr. Carlson ! Your explanations are both clear and concise and entertaining often ! I wish I had decided to become an instructor years ago as I think I would have followed your lead. My instructors were quite dry most of the time and thus quelled most of my original desire to learn electronics as originally intended. I look forward to following your coursework. The materials of CREI were my original material obtained and it was quite good. They were sold to another company and quickly went downhill , dang shame as many followed them at the time.
I'm going to be building a little transmitter with a 1Zh37b rod pentode once I get all of the parts ready. These unique Soviet subminiature tubes use closely spaced rods rather than grids and have unusually good low-voltage performance.
My dad has one of these back in the fifties but it broadcast in FM. I didn't Knight Kit made an AM model.
lmao, butter knife and torch. when i was like 7 years old and i started taking my first electronic stuff apart all i had was a butter knife and the stove top. i still have a faint scar on my wrist from where i was trying to resoldier a pair of headphones and slipped and laid the end of the redhot end of it on there. later on, i begged my dad for an iron after that.
fml many tears were shed trying to work with no flux and a hot butter knife before i knew what was up.
I used a piece of copper, i think it was a copper nail, tied to a piece of thick wire (no idea what it was, but you couldn't bend it with your hands). But still on the stove top :) i guess, a lot of us start there.
Growing up near Chicago was always torn in my locality between Knight kit and Heath kit.
My first kit was a Knight VTVM, saved up all summer 1961 between 8th grade and freshman high school.
My brother and I had something very similar to this back in the 70's. It was a 7 or 9watt AM broadcast amp. We would broadcast our radio station WAMAMFM through out our neighborhood. I'll never forget the fun we had. Sometimes my brother would walk up to Mr. Doughnuts at the end of our street to buy cigarettes from the vending machine there for 45¢ and he'd have his transistor radio with him to check our signal strength while I would broadcast. I'd broadcast what kind of doughnut I'd want him to bring home and would have to promise over the air to pay him back. It was sooo cool when he brought home the right flavor doughnut.
I never knew there were that many young guys like me that loved to “experiment” making our own broadcast stations. Later on I bought an FM kit and supposedly it had a limited range. I was able to pump out a signal for about a half mile or so. Didn’t have a PLL so the signal would drift. But it was fun.
Another really interesting video of yours, and I appreciate it's not intended to be a high-spec device, but could we have a bit more technical analysis of it please?
What was the maximum undistorted modulation depth? And min and max modulation frequencies at the 6dB points? How many mV required at the input for maximum modulation? Was there a significant amount of FMing on the simple AM transmitter circuit - particularly as modulation is applied to an L/C oscillator? How much does it drift from switch-on?
With the recommended antenna, what is the approximate range using an average radio for reception? What was the frequency coverage? Was it the full AM band or just a section?
In your opinion is it worth any of us sourcing the parts and building a reproduction of this vintage design - despite the obvious safety issues?
Thanks.
Sir you are the Albert Einstein of electronics , once again great work . Your friends from NYC
It is of course illegal to create radio transmissions without a licence in the Uk, be they commercial or amateur. apart from certain radio bands such as CB Radio (27 Mhz) and 315MHz, 433MHz, 868MHz, 915MHz and 2.4GHz
If that kit was available in the UK the chassis would have to be earthed (grounded), especially as it is a transformer-less circuit. Thinking about it, it would have a mains transformer to improve safety and use 6.3 volt heater (filament) valves (tubes). The UK and Europe have 240 volts mains, so dropping the filament voltage would be less easy.
I know Mr Carlson is being deadly serious when he says "You're doing so at your own risk".... but I still chuckle every time. It's like his signature tagline. It wouldn't be a proper Mr Carlson video without it.
Imagine if he uses that line in his day to day life. Like he wakes up and makes coffee, and hands a cup to his wife. "If you're drinking coffee with me, you're doing so at your own risk."
...
Then he takes his kids to school... "If you're getting less than A's in math, you're doing so at your own risk."
...
Then he goes to work... "If you're collating those documents, you're doing so at your own risk."
...
Then he comes home and the wife calls, saying she'll be late and to please go pick up her mother at the airport. He replies... "If you're asking me to go pick up my mother in law, you're doing so at your own risk." His tone is especially calm and neutral for this one, sending shivers up the wife's spine.
...
I'm just joking around, but High Voltage is no joke. Don't play with it unless you know what you're doing. Keep one hand in your pocket at all times, and remember... you're following along at your own risk!
Mr. Carlson, Dating myself here but, When I was a kid back i'm guessing in the mid 50's or so. Myself and a couple friends used to order stuff from Allied radio all the time. Transistors were I believe about .99 cents each, We built transistor radios with 2 or 3 transistors in them (that was fancy stuff at the time) Anyway one of us bought and built that kit, I believe they called it a wireless oscillator at the time. I lived about 1 mile away from Paul (he's the one that had it). When I left Paul's house I could hear him till I got almost all the way home.
Ok, I'll be the gumby to say it. Mr Carlson looks like a very young version of the doc. This is really episode 4 where he's stuck in 2020 and misses his childhood transmitter. And, yes the radios RF output is 1.21GW.
Very clean. You could probably send CW a mile or two.
Years ago, I built a Ramsey FM stereo radio transmitter. I didn't know what to expect but the Ramsey transmitter can transmit a high fidelity stereo signal about a half mile with the small antenna that comes with the kit. You could probably transmit a better signal with a better external antenna but I have never tried it.
Great video. As a kid I built a Radio Shack low power AM transmitter and adjusted the tuning up to the TV channels so I could jam the video of our own TV. We had only one TV and if I jammed the channel my sisters wanted then I would get to watch something better on another channel ! Worked great but eventually I got caught. I guess it became obvious finally as after an argument over what channel was going to be watched I would run upstairs and tune the transmitter until I heard screams of displeasure downstairs 😂.
Omg, I built one of these when I was 12. 1958? How cool to see it again. I used it to re-transmit my favorite FM jazz station (KRHM) so I could listen to Miles Davis out in the backyard. Man was I a hepcat kid or what? 😂. Thanks so much Mr. Carlson!
Hi Paul,
I would like to ask why you don't use nano-farad? You say 0.0047uF or 4700pF, but we normally use 4.7nF. In the past, multiples of nF were not really used much, but today they are commonly used.
You're making my life more fun just listening to you!
I could really see myself using this in my teens. I used a really crude Walkie talkie setup and for longer transmissions a mobile. This was when Mercury released a free 6pm-6am tariff.
Man I was wondering what the blue & black device was doing, displaying random numbers. Then I realised it was my phone's voltage.
I learned the hard way about no Isolation when I was a teenager I tried hooking up a ground on a tube radio and when I touched the ground to the chassis, KER_POW!!!!, ARCED and blew the house fuse! Luckily the wire I used was insulated.
I wanna see one for shortwave radio. I’d set up a hifer radio beacon at 13.565.000 MHz under fcc part 15 lol. Hifer is the acronym for high frequency experimental radio.
An interesting video. I had not heard of this device. In my ham career I've played around with Knight Kit transmitters. AM radio, hmmm I may or may not have "accidentally" warped the tuning of my Viking Valiant's 160 Meter vfo into the top end of the broadcast band.
Omg all the oscopes around you.. can I buy one.?they all look like 70"s to 70s models. Kudos on an amazing video I will now subscribe..I have just found your vids . Btw can this be used with an FCC license?
Wow did that bring back memories. That was the first transmitter I ever had. I put it in a wooden box and modified it to also be an intercom. I somehow lost the unit over the years but it was the beginnings of my lifelong carrier in TV, Radio and Microwave broadcast RF engineering. Thank you Knight Kit and Mr., C
This episode sure brings back memories! I built many Knight-kits (and Heath-kits) in ages past. I didn't build this particular one, but some of my contemporaries copied the schematic, added an RF amp stage, and began broadcasting AM radio, playing 45 rpm records. The signal carried several miles, but had to be retuned when someone accidentally bumped the counter!
Boy is that thing dangerous, I usually avoid anything without a transformer. Even if you got the plug in the right way, when you turned off it's power switch, which is in the neutral side, everything is going to float up to 120V, lovely.
I once saw a design for the ultimate in dangerous NiCad battery chargers, it had a light bulb, a diode, and the battery holder strung directly across the mains! They did recommend putting it in a box with a lid switch to isolate things when you opened the lid........
I still have my Knightkit Broadcaster. I built it around 1961. Three of us in our neighborhood used them to "ham" with. I also used it for a guitar amplifier. And I subsequently got my Ham license....56 years now.
Are you operating these days? I have a tech license, but am crrently taking a break.
A relay, actuated by the effect of a magnetic field developed by the current in its energizing coil(s). There used to be 4 manufacturers who built this device, now there are still 3 offering it to the market. Originally, this device was used by the military (like many of those things). BTW, Paul, next time please hide the part number on the device. This one was easy to read and google offered the answer right away. :)
Are you feeling all right Mr Carlson because this must be the first time ever that old capacitors have not met the Carlson's lab bin of death...........I thought the weird valve thing was some sort of training aid but I know I am wrong!!......Great video .:)
Wow - I went back to my own little example. Replaced C-7, the 470pf - I had no suitable mono caps, so I used a 470pf silver-mica. It's as stable as the transistor radio I'm using to 'preview' it.
It used to drift for about 20 minutes before it warmed up.
Thanks!
Hm. I've been trying to build a gilbert cell in ltspice and studying the superhet again. I just learned earlier today the definition of "heterodyning" as a verb(Weird we never discussed it as that term in my communications class), so I actually knew what you meant when you said that. Fancy coincidence.
Items such as what you presented here, can be found at Ham radios swap meets. I like to pick up such items as they probably do not work, and see if I can make them work. Some of my favorites are Heathkits of all kind, as these items where all built by someone, and the manuals for them can usually be found on the Internet. I like the simple kits, as they are fun and easy for me to trouble shoot and they maybe useful in my Ham radio. Thanks again for a great job of explaining how all of this "old stuff" works!
You might have restored it and compared its "new" specs with the old ones... commenting on the change. A frequency plot of the transmitted audio would have helped, also... to show that "small is also useful." I owned one back in the early 60's and used it at a boy's camp for fun. I also taught amateur radio and was a swimming instructor as well as having a cabin full of kids.
I had the Ramsey Am Broadcast TX kit, fun to build and use for my local neighbors, they liked listening to me every evening. Miss the closure of Ramsey Kits!
Mr Carlson, I am not an engineer nor do I know anything about electronics. I simply enjoy watching your content. You are so intelligent. I learn new words every video. Haha. 43 and still learning and entertained. Thanks
Paul, I've watched this video a couple times now and this time the came to me, " Why doesn't Mr. Carlson build a AM broadcaster like this ... only better" and post it to Patreon!
Mr Carlson, have you tried to back feed audio through the secondary of the audio transformer from another amplifier? As I recall from my youth, that will improve the audio quality of the Knight broadcaster.