I am from Argentina. I started with this "hobby" when i was...say...13 years old, thanks to a little magazine called "Lupin", where an entire generation found how to make a radio, a photo camera, rockets, amplifiers, little planes, boats, hovercrafts....and so on...nowadays, being an electronic engineer, specialized in computer networks, I had the urge to " go back to my begginings". So, here I am, looking at your videos with my thirteen years old eyes again! Thanks a lot for the fun!
Dad bought me one of those Remco crystal sets back in the 50s. As we were putting it together (and Dad did the assembly, with commentary and appropriate curses), he told me how he and his brother used to build them out of old wire from Ford ignition coils and crystals from the talus dump at nearby lead mines. He said that he would listen to WLW and KDKA on it . . . which surprised me because at the time Dad and Uncle Nils were living in Arizona. He said he ran a wire for an antenna between the outhouse and the peak of the house roof, which angered his father because Grandpa Tom's peace was disturbed by the wire's resonating in the wind, which made the house hum. ;-) Six decades later I still have a crystal set -- one of Elmer Osterhoudt's MRL #2 DX sets -- and have built many others. Them and the latest micro SDR from China. Six decades of radio from one crystal set and a story my father told. Plus six years in the USN as a radioman, a job title that no longer exists. 73 de W8IJN
I remember using spring loaded laundry pegs glued to a board for wire clips. It did the job, with tacks. So long ago, now am 72. Thanks for triggering my memories.
Thanks for an excellent video, Mike! On an early crystal set, I used a 2-gang variable capacitor from a $1.50 garage sale radio. My antenna was a fifty-foot-long 16 gauge extension cord that had a ground wire. I wired all three terminals together on the plug end with my lead-in wire, then I threw one end of the extension cord up in a tree. Sometimes I've purchased 20 gauge, two-conductor speaker wire at Menards. (Building supply) 100 ft. for 5 bucks or so on sale. It's copper-clad aluminum but it works fine. Separate the two conductors and you have 200 ft. of wire. I've used this same wire to wind coils with good luck. I once built the MRL # 39 crystal set. On a 2" pipe (PVC) I wound 80 turns of 20 gauge wire. I wound one turn of duct tape over the center of this winding, then I wound 40 turns of 20 gauge over this. The set worked really well. One day I was jumpering across different terminals when the sound just boomed in on my headphones. For comfort, I had to tune off the station a bit to decrease the volume. Days later I couldn't recall which terminals I had jumpered. Since then I have often tried to discover what I had done to no avail.
Someday I will build a crystal set. Too many more complicated projects going on. I'd probably experience feature creep on a crystal set too, lol. Thanks for the relaxing 30 minute break from beating my head against the current project.
Great work. I'm so impressed with the performance of your radio and how well matched your coil and capacitor as well as your antenna and loading coil appear. Also I appreciate the demonstration of the effects of the loading coil. Now I know I must construct one. Thanks again for your time and expertise.
You could put a silvered mica capacitor in parallel with your varactor to put it in whatever portion of the band you wanted. Pill bottles make an excellent coil form. I really like the idea of using a varactor. Your radio is far more selective than anything I remember getting with my radios. My friend next door built a crystal set but couldn't get it to work. I found the problem and fixed my first radio at 5 years old.
receiver from kits. Owned a 1930's Hallicrafters S20R shortwave set. This takes me back. Since I can't find the old radios, I'll just make a new crystal set. Thanks .
Excellent presentation! Much nicer than my first "Cats whisker" set I built when I was a kid... I wanted to build up a couple with my grandkids last year but was disheartened when I saw how rare and how much Air variable caps go for these days... You've given me hope that I can still pull this off! Thanks you!
This is a good video and a good radio to build I suppose. I haven't done so. The gentleman has a dry sense of humor and knows his stuff. The only thing missing is a pet dog or cat for a break in the tension. ;)
Mike Great video, As a child growing up in the '60's I remember my Dad's "junk box" of salvaged radio/TV parts. We didn't have much money for spending on hobbies. We used to unwind old flyback CRT transformers for magnet wire. Coil forms were what ever non-metallic tube was available. (In the 70' and 80's it was 35mm film canisters for HF. '90's up plastic Rx bottles) Many a breadboard project was made using those old brass clips and recycled terminal strips. I am sure Dad's soldering iron was actually a lot smaller than the monster in my memory. Sadly most of his "junk" was tossed when my parents moved into a smaller house after us kids grew up. After Dad passed in '93 about all that was left was his Knight kit "Star Roamer" he built in '62 or '63 and his Midlands CB radio.
Those spartan scrap and junk parts and projects from younger days are highly regarded by many who frequent this channel! It really is a whole contruction philosophy and style in itself, that can last a lifetime.
Your presentation is very interesting and descriptive. I am inspired to build my own crystal radio. Only occupying recycled and reused material. Many greetings.
My first crystal radio in my youth had the ends of the coil enamel wire scraped off and stuck between the lid of two flat sigar tins. Sheet of paper in between and there was my variable capacitor. Germanium diodes were still the standard in those days, so they were easy to get for pennies. Funny how these crystal ear pieces haven't changed in 50 years. Still the same skin color-ish yucky color and a twisted pink wire 🙂
@@MIKROWAVE1 I did some investigation as to why they fail and it's usually because the leads aren't secured to the piezo disc inside. They're just held on with a dab of glue. It's possible to open them up and fix the issue
I've made many Crystal set Radios over the years. I would love to have a longer garden, mine is about 16 feet and that is where my problem is. I have two long wire antennas, one in the garden and one in the loft, which is also 16 feet. These antennas are good enough for a simple regen shortwave radio, but that is about it. I have some parts ready to make an antenna tuner similar to yours, it might just help a little bit more.
Try an indoor loop antenna on a form and use 18 gauge lamp cord "zip wire" closely spaced (edge to edge) which makes 50 Ohm impedance then solder to R58 coax (must have copper braid to solder well). You will have to experiment with some sort of variable capacitor across that junction to get the coverage you want, but I think it would be fun. I have 2 loop antennas mounted up above my roof and they work great. One uses 14 gauge TTF wire (control wire) close wound and the other uses TTF 16 gauge spaced 3 inches apart and a Balun to RG6 coax with a capacitor tuner circuit at the Balun--this works well for shortwave and AM.
When I was a kid, I built a crystal set that had a fixed capacitor. The coil was sanded on the top to remove the insulation and an "L" shaped piece of metal, screwed to the board and was set to rotate over the coil forming a variable coil. I believe I was a cub scout at the time and I believe that the scouts were selling these kits in the Boy Scout stores that were around the country at that time. it worked pretty well. That would save the cost of the 365 pf variable.
yeah, definitely makes sense to have a fixed cap. even with the variable cap, I thought there’d be a fixed cap in parallel. - I’ve hand-built a capacitor before, (it was large, and had a tiny capacitance, but technically it worked.) can say with confidence, it was “variable,” 😅 physically squishing it to get the plates closer together increased it’s capacitance! let go, they’d spring apart some, decrease capacitance. 😂 one day I’ll have to try doing this to a crystal radio.
I love the gentle humour you put into these videos, especially this one. I followed this with great interest and will have a go at building one, if I ever get a day off work!. I'm fortunate in that my garden or "lot" is 460ft long, so should manage 200ft of antenna easily. Have you ever built a crystal radio which will work on the ham bands. I would be interested to know if it is possible with the right coil windings etc. 73. Ace G6XIB
@@paulsengupta971 Thanks for your reply, although there isn't much AM on the ham bands, there is some and our licences allow us to use it. It would be good to fire up my rig on AM and see what a crystal set picked up. I don't think a BFO is required for CW, Carrier Wave but it would not be out of the question for SSB. I like the challenge of a crystal set on such frequencies and it would be fun to try, even if picking up my own test transmissions. I have several friends who like to play with AM and I may experiment with double sideband in the future. Also, hopefully a crystal set will slope detect FM. Best 73 G6XIB
Amazing explanation and practical demonstration. You Sir are an exceptional instructor.. you've made it digestible for a novice like myself! Thank you for your time! Subscribed (Check)
You can never have too many variations or crazy things to do with a device. I worked with this guy at ADI, Walt Jung, who wrote a book called the 555 Cookbook. Do you think that was enough 555 circuits for everyone?
Mike.. do you use the variable inductor antenna tuner..a la Tuggle??. I find that works pretty well.. I have used PVC couplers as coil forms..3, 4, and 5 inch.. may be my imagination but the 5" with #18 or 20 wire seemed best for me .. but getting it all on the form was sometimes a challenge.. I'm interested in the varacter.. never did that..
I'm curious about how far away a crystal set can pick up broadcast stations. My closest AM station is 80 miles away in Ottawa and 130 to Toronto. I have room to put up a 200 foot antenna about 30 to 40feet high . Any recommendations for making it pick up distant stations?
With a fine antenna like that, and no overpowering station close by, you are in a place that would make most of us jealous! Just wait till 7PM! You may need to reduce coupling by reducing the input (primary turns) and your tuner can be less turns like 150T of thicker # 22 or 24 with an antenna that long. You will hear stations as far as Winnepeg and Nova Scotia Ha. US Clear channels at full power like WNBC 660 kHz New York should sail in.
Mike, I don't remember what I used in 1975 when I did my first crystal set for my antenna. Now I want to do one with my grandkids. Do you think the insulation can be left on some small telephone wire for an antenna? I have a few miles of that !!! I don't want to disappoint them once we get it all done. Our local AM station is about a mile for them and about thirty miles for my house.
You can do everything with good old telephone wire! I don't know how long it would last but 75 to 100 feet of wire should do it. I suppose you could twist a pair for more strength.
@@MIKROWAVE1 I'll give it a go then. I want to try it out before they come over and I disappoint them not knowing what I'm doing. Thanks for the reply.
Hey Mike. That's not a real crystal set. The real deal was the Philmore crystal set with a piece of galena with a cat's whisker , a coil of wire with a slider (no taps) and head phones. I got one in 1953. Hooked it to my bed springs and have been hooked on radio ever since. Love your channel. I wish I lived next door to you. If you reply to me with your mailing address I will send you two things which you can really appreciate and maybe amaze you.
@@MIKROWAVE1 Hi Mike. Thanks for the reply. I was kidding of course. Your videos are the best. I have several nice pieces of galena if you are interested.
So glad you went the full measure with using an appropriately rated, voltage wise, bypass capacitor. You might also consider in future videos recommending that the viewer, if they construct the project, use it only as intended... no edible parts... etc. In other words, all applicable safety warnings, alerts, shout-outs, pleas, and so forth and so on... with the international symbols indicating danger, warning, caution, etc. posted as well. No sense opening up oneself to legal entanglements. As we all should know by now... these projects are for educational purposes only and no medical cures for post nasal drip, flat feet, acne, etc. are implied either. 73s, 45s, and 33 & 1/3s to you!! 😊
@@MIKROWAVE1 Yes... new solder... the kinder & gentler one... “lead free”, you know. No accidental brain damage should one mistake wire solder for... I don’t know... a 100 foot long ‘Twizzler’ candy or such. Perhaps the solder manufacturers could flavor the flux. Anyway... stepping back in to reality... love your channel. Keep the projects coming. Life is for learning and I enjoy your teaching style.
@@kennethandrysiak4130 As well as Mikes 1kv cap warning you should always use a insulated tuning knob no larger than six inches or the coil could get damaged by static! /
Many moons ago in one of your vids, you said you were going to use a diode tube in a crystal radio circuit. Did you ever do that vid? Thanks, I always look forward to your videos.
as always good video... hey talked to ur nabor today. AL. TP. iam sure u know what TP is. asked today on net if anyone knew ya hahhah.. he admited to it lol.. your not much of a net guy ? more a code type of guy hey ? and waiting for the varactor build
MIK ROWAVE 1 I got a crystal set to billed when I was a kid my dad help me billed it from radio shack and I. Got a shortwave radio kit from radio shack when I was a kid my dad help me billed it and it work will I wish I stail. Had it
I think the important thing about crystal radios and other simple receivers is that it allows you to start experimenting, often because you can't get the specified parts, as you described very well at the start of your video. My first mod was to add a transistor as an audio amplifier, which in 1960 was a "Yellow Spot" germanium p-n-p device. It cost nearly £1, here in the UK, which was $2.80 in those days. It had been used in a pocket radio kit which my brother had given up on. It was handled with great care as it was worth more than a week's pocket-money.
I probably made 100 crystal radios in my life and I couldn't get them NOT to work, regardless how bad my building techniques were or how shitty my parts were I was always able to pick up local AM radio station.
You don't need to spend a hundred dollars on the parts just about$25 all you need is a coil that you can salvage from a radio that has been thrown away and a .365 mfd veritable capacitor and a germanium diode and a crystal earphone and a thin board or perfboard
When it comes to antennas i really became a huge fan of these "cobweb" antennas that lets you put all length into a smaller space and even making it become an integral part of your crystal set. Smaller footprint is definitely possible :)
Great vid, love CRs & thanks for sharing the knowledge. Just to verify, you stated the need for a variable loading resistor when using an external amplifier. What value is optimal, or is a fixed resistor possible for that purpose?
Really the load needs to be as high as possible for the greatest voltage output; but 2000 Ohm headphones ruled for years. Now most folks use crystal earpieces and a 47K resistor across the output. Fancy radios use transformers between the output and the headphones for maximum power to the ears! So for an amplifier keep the impedance high.
My first working radio used a vacuum diode instead of a Germanium diode. Given that I loaded the tank circuit too much this probably was a good choice due to the low forward voltage.
My first radio was much simple, you just need a radio antenna a germanium diode EFD 108,a speaker(2000 ohm impedance) from a old phone with carousel dial, a ground connection and you can listen AM local radio station no battery needed.
Hi! Just for G.P. , A lot of the parts I ordered from walmart- 1n34a, mag wire, var cap, crystal earphone phone, etc., prices aren't too bad, Shipping is often free, Also, whenever I find any thrown out radio, or other electronics, I strip it for parts- I'm retired now, sooooooo, This is something to do 4 fun- Anyway, GOOD VIDS!
Never heard a crystal radio pick up so many stations. You're antenna tuner made all the difference. Before I was a teen-ager and many years after, I had a crystal set beside my bed that I listened to as as I fell asleep. My crystal ear piece went bad and haven't played with it for quite a while. In my 2020 issue 1 Nuts and Volts magazine they built a replica Crystal radio kit Allied Electronics in Chicago sold years ago and is very similar to the set you built.
Those old crystal radio projects in the magazines are fun to read. Many are scanned and online now. This design is pretty standard for a basic set. The Loose Coupler approach takes it to a higher level. The fancy air low loss coils and proper High-Z output transformers take it even higher.
I’ve been tinkering with crystal radio for quite some time and when it becomes much more than that I get lost . I did however figure out that an antenna was a giant capacitor . I’ve made a few different types from lo AM broadcasting band into shot wave . I enjoy watching your crystal radio builds as you explain it well . I only wish I could have learned more from a local operator called Doc before he died . One of the simplest books I’ve read about crystal radio is one by KE Edwards , and for all of those who say they can’t afford the parts Edwards tells how much of what he built was scavenged from old style TVs with a picture tube . Not every one I’ve made worked . Never got Boston stations till I put an amp on it , but I did get NY , Canada , and as far south as Washington an Virginia without an amp .
I'm here because I'm trying to rectify EMF to do RF energy harvesting. I picked up BAT46-TR diodes, they start conducting as low as ~150 mV and they're rated for up to 150 mA of rectified current. I managed to pick up 6 V for charging a capacitor and 125 uA of short circuit current flow.
My crystal set in 1990's pick up strong SW station "Неметская волна" from Russia. Today many stations shut down and crystal radio go to silent... Good alternative is a TRF receivers from 1..3 transistors.
I buy old 70's radios at thrift stores and salvage the double ganged aluminum variable capacitors that are normally found in them. I also found that the type of variable capacitor used in Am/Fm transistor radios from the 60s & 70s are available on EBay for very little. As far as diodes, if you can only find silicon diodes a bias applied to the diode will do the job as well as or nearly as well as a 1n34a diode.
Mike, I truly enjoy watching your videos; you explain things so clear and effective that the new person without electronic background can understand and not get overwhelmed. Thank you so much for taking your valuable time and teaching us your techniques so we can preserve part of the history and older technology. Have a great day! Regards, Jay
I think I would go for a capacitor made from aluminum foil and paper. Basically places them one on top them other for maximum capacitance and then slide one off the other to tune to less capacitance.
I was on my bench one day and on a whim, I measured the inductance of a spring. I then found you could change the inductance of that spring by a good 20% by stretching it a reasonable amount. You couldn't expect it to be very stable but you could use that as a tuning mechanism just for fun. I've never seen that done before.
Crystal and Ceramic earphone do not provide the required DC path to make the circuit current flow. The audio current through the resistor causes the voltage. The capacitor filters out the RF and causes the audio to be peaked DC level.
Beautiful fox hole radio model nice video sir please make new video testing fox hole radio without amplifier testing on Mike I am waiting sir from india good job sir
I don't recall reading about using a varactor before for a crystal radio. Immediately, what came to mind was using aluminum foil or aluminum duct tape (copper also) or using aluminum cans with plastic bottles or packaging tape as the dielectric since there are so many sizes now days. Whether two sheets or stacked design (PCB's can be used as well) or the tubular designs (scrap copper pipe can be used)... those are way cost effective. Just Google DIY or Homemade Variable Capacitor. I still have the habit of saving my cardboard tubes (just a few days back saved a large Oatmeal one) and have a stash of odd sized cans and bottles just for variable caps or inductors. One can even invest in one of those ~$17 LCR-T4 Mega328 and just checking that I see IMSAI Guy found a newer $17 one that doesn't looks so ESR'ish than the LCR-T4 I use.
I punch tiny holes and run the wire through the tube after measuring how much winding I want - so I have a beginning and end ready -to anchor both ends. Then run the spool from a spindle through a couple of books with weight on them to tension - and carefully wind!
Wfin, Wfob, wima, wspd, and wtbn were my favorites. Summered in Bascom ohio. Wintered in arcadia ohio wtam came with some tweaking. wjr , CKLW, woai, and WBAP came at ft hood texas in my army days and for the cost of a wrecked aa5(striped CHASIS) found in a trash bin. Was the cats back side back side beeing that I got paid about 90 bucks. A month. It was cheep. ( No power) interesting to my CO. That I got a (unused closet). On the top floor. Of our barracks.( No strings) as he would visit. And tune through the band. (Circa1972) thanks. retired Sargent williams. Thanks ps he promoted personal hobby's said it cut down on AWOL rates. As we were on a ready LINE. For flights to disaster area's we were a multiplex phone unit. That was put in place to compensate for storm dammage.
Could you explain the antenna again clearer please? I don't understand, how was that tune to another antenna? What I'm specifically trying to figure out is how to improve the AM reception on my stereo. I'm thinking of building something overkill in the attic. I have a 2 story steep pyramid shaped roof (I can walk up there) and was thinking like a big coil around the sides so I can still receive signals from all directions. I thought there was a way I could also build some sort of wireless antenna resonator for the downstairs that I could alligator clip my stereo to.
Even a small loop antenna can improve AM reception. A tabletop tuned loop is useful, but I like untuned coax loops that you can place remotely and not have to tune. An untuned loop in the attic with a rotator will allow you to maximize signals and more importantly, null out noise. chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/www.nonstopsystems.com/radio/pdf-ant/article-antenna-magloop-EWS-MW.pdf
Would that work in all directions or would I have to point that around to maximize amplitude reception from the stations? I came across this design before, was even thinking of modifying this into more of a spear shaped coil (I hate being an audiophile) so I can just hang it up there and leave it alone. I got plenty of room I could do probably a 6 foot sphere. I think for my case using foam-board for the support structure in the center won't interfere with the reception. Is my logic wrong? I'm new to this and trying to learn more.@@MIKROWAVE1
@TheTarrMan OK I get what you want to do now. Yes a simple length of wire in the largest geometric shape forming a loop is a good plan. I assume that your receiver has an external antenna connector?
Yes, (Pioneer SX-1250). Finally moved into my first house and I want to set up my stereo. (The T style antenna for the FM works awesome but the plastic coil Amazon thingy for the AM is crap.) Thank you for your help. @@MIKROWAVE1
Yes. I own a Pioneer SX-1250. (Basic thumb-screw terminal on back. I'm going to need to make sure the ground terminal is connected to this also, aren't I?) Finally moved into my first house and I want to set up my stereo. The T-style antenna for FM works awesome but the Amazon plastic coil thing is crap. (At least my experience, probably because I have a lot of interference.) So I guess I'll do a big spear. . . maybe three turns. I'm going to put some mylar thermal blankets underneath it to shield any noise coming from below, should just be the sky then. Thank you for your help, those links were useful. @@MIKROWAVE1
First found your channel when you did the loose coupler and crystal radio. Full circle thing? If you want unobtanium, try making a proper .01 cap from cigarette foil and cellophane. 30 tears ago I could ask a couple of friends for their empties when out for coffee. Now......
This brought back some memories.. Back in junior high school.. one of our class projects was to build a crystal radio from a kit.. (I think RadioShack)... very simple and inexpensive.. and it worked..!
I had a good laugh watching this. But yes I’m from Europe. And today I was looking for a simple tungsten filament lightbulb. Did you think I could find one in the hardware store? Nope, Apparently. Thats now an industry use only! I had to order one from my nextdoor country😆 Also 50volt Mylar caps that are not cheap China unbranded for a restoration project. That are also through hole. But I like that headphone you showed. I’m gonna look up that one. Thanks for sharing you’re knowledge.
