Crystal Set Part 3 Loose Coupler

[@laythabdulwahab9498]

Yes you are history of electronic and communications.i feel happy because you pulled me back to fifties and sixties time.i followed all your videos and i feel in all of them the old nice test of radio and transmitters with valves .it was great days when i made them by my self .so i present my respect and thanks for you for your effort .your videos are history,teaching and development

[@Jomatsch]

In '73 I built a modified MRL-11 crystal set. Five coils were wound on a 2" form using #20 enameled wire. Individual coils were 5,10, 15, 20 and 25 turns, each separated by 1/4". Five DPDT toggle switches. Switches would allow me include or exclude individual coils to eliminate dead-end effects. Devised this circuit during many hours of watch time while in the Navy.

[@clifffiftytwo]

Love the Hickok signal generator @ 26.28 and later - I'm trying to get one working right now. It's oscillating inside but not making it to the output. Work in progress. Now I've got to make a crystal radio, too. Thanks, Mike!

[@KB4QAA]

Great tutorial. Loose couplers aren't discussed much and I have wondered about their construction and usage. Many thanks, 73, bill

[@Inertia888]

Well done sir! You've got my mind running down a whole new path.

[@mikesmuseum]

I really enjoy your videos! Your explanations and insightful comments really add to what you are working on. Your attention to detail is exemplary. Thank you for sharing your knowledge on crystal radios, and showing that awesome mini tube amplifier, and that fantastic loose coupler you made! Keep up the great work!

[@Inertia888]

These few videos are so densely packed with information, if I had watched the final few minutes of this part three before the lesson, my mind would have went blank not grasping what it is that is on the screen. I have a noticeably more firm understanding of this subject now. Time to wrap some coils!

[@acestudioscouk-Ace-G0ACE]

I found this both fascinating and confusing, I guess I have watched too many of your videos too quickly and need to build some sets for it to all sink in. That after all, is what it's about! Thanks.

[@MIKROWAVE1]

Get the hand tools and soldering iron out, and build some of these. But caution: crystal radio building is addictive.

[@acestudioscouk-Ace-G0ACE]

@@MIKROWAVE1 Thanks Mike! I'm collecting parts and am nearly ready to go. I'm fortunate in that I have enough space for a long wire antenna.

[@stephenwilliams5201]

Mine was given by a elmer. At w8ft findlay. I listen to mine for ball games, and foot ball in the fall it's 98 years old. And the elmer told me to keep it for him. De kv4li /// I keep diode and tuning cap on the same board. I kinda show off by putting output on a guitar amp kids get a kick out of that 73

[@MIKROWAVE1]

Wow!

[@radioguy1620]

Well done video, nice shop you have there.

[@Survivalist2008]

Another great series. Thanks!

[@joel6221]

i'd LOVE to see complete plans for this (and other crystal radios). I'm a graphic designer and would love to help you develop them!

[@MIKROWAVE1]

The shop teacher found the instructions in an old Electronic Magazine from the early 70's. I have yet to find the original article. There were many fairly detailed instructions on how to build a loose coupler in the early 20's publications. worldradiohistory.com/UK/Popular-Wireless/1922/Popular-Wireless-1922-11-04-S-OCR.pdf

[@mheermance]

Interesting video. I wish you provided a link to a measured drawing. The injection of a signal to demodulate CW and SSB could be a video on its own.

[@ronaldjorgensen6839]

great to see it all

[@matthiaswilhelm9813]

How many Station can you Sharp receiving in the evening houre.merry Christmas👍🎅💒with my 2 Coil Crystal Set with Schottky bat and 2 Couplet coiles Selfmade i received 16 AM Stations.Matthias.The Telefunken original have 2 Riders in the Coil.

[@StalwartFixer]

Could you show the inside of your secondary coil and it's taps/wire routing in more detail please?

[@samuelsprayberry6797]

I want to build that so badly! So it can be built to do AM and shortwave? And that amplifier is awesome!

[@ludost5178]

it can be built to catch most stuff...

[@StalwartFixer]

Cool radios. I noticed there is a pretty large gap between the secondary coil and the primary coil, If you used a larger former for the secondary coil and had less of a gap how would it effect performance?

[@MIKROWAVE1]

Like all RF transformers that are tuned on one or both sides, there will be a loose value that gives very sharp response but with reduced level, then a critical coupling distance that will give what we are looking for, and finally over coupling, which will provide less selectivity but more output (possibly from interference!).

[@KB4QAA]

Stalwart: Your proposal would increase the coupling between the two coils. However, we are not seeking maximum coupling (efficiency). We have more than enough coupling, and indeed the name of the component is a "Loose Coupler". by using loose coupling we make the tuning less critical (sharp) and can make adjustments more easily. bill

[@chrischris6147]

interesting thank a lot for vidéos about crystal and regenerative receivers

[@Jeffrey314159]

1:20 There no AM broadcast stations prior to 1915.

[@nor4277]

I would love to see you help our scout troop, to make simple version .pass on your skills

[@clytle374]

Extra credit... Tube amplifies RF back into the antenna coil, RF portion of signal goes though the cap across the phones. Tube also amplifies audio signal and also works as the detector. I can't think of the term for the radio that uses the tube for both RF and audio... I might be wrong, circuit could just be an oscillator lol Can you share the source of this circuit?

[@wa1ufo]

Wonderful!

[@AINews13]

You said you don't see the utility of the dual slider system, but the text then says "unless you want to double tune." What is double tuning? Is there an advantage to it? BTW, I'm eatin' this stuff up! Thanx for the great informative videos!

[@MIKROWAVE1]

I meant a slider on the primary and a slider on the secondary with each tuned - and the coupling sets the passband. This could give more selectivity at the expense of gain.

[@AINews13]

Thank you for the answer! This was the 1st KZbin video that got me interested in building my 1st radio. I built a loose coupler (and the componants that go with it.) But I've searched your videos and can't find how to build a wave trap or band-stop filter because there's a station near me that blasts over all but 2 other stations. Do you have a vid on building a wave trap? BTW, you are the easiest to understand for a novice like me! Thanks again for your great instructional videos!

[@mikepasko7493]

were can you get the parts to make the slider ??? and how can you improve the coil ant on the back of a 5 tube radio thank you

[@joel6221]

I'd like to know this as well ... i've tried making my own to no avail.

[@IndoCropCirclesOfficial]

Could you make a crystal FM set in the next video

[@kb9agt]

Sort of like the MFJ antenna tunners, you want to set the capacitor midway then tune the coil.

[@edmaurus2511]

I'm in Detroit and at night WBZ takes over for the local station we get here.

[@deltayanki7461]

saya banyak belajar dari anda tentang redio crystal

[@MIKROWAVE1]

Apakah Anda siap untuk membangun radio kristal mewah sekarang?

[@carlosmarmeli1581]

Que maravilha como existem novas coisas por se aprender e tomar conhecimento isto é muito bom Alécio muito e gosto muito exelent abs 73.

[@red_ford23]

Do you get the longwave Morse beacons or any interesting data burst or time sync signals? On the big one I mean I did watch until the end, just commented too soon.

[@MIKROWAVE1]

Now here is where the BFO idea really comes in, as most of these are based on carriers than an AM detector can not handle. NDBs should come in with a long antenna ( think at least 200 ft!) since they have AM modulation.

[@chrismosley409]

is there any activity on the low frequencies that the big one was made for? on the little one, did you use the same guage wire for both coils? how many turns? I like the stain you used. what was it?

[@MIKROWAVE1]

+Chris Mosley I actually used # 20 on the primary (Larger coil) and # 22 on the Secondary. The stain was Minwax Dark Walnut. You just paint it on and then in 5 minutes, wipe it with a cloth. Then 24 hours later, put a finish on like paste wax or Polyurethane. The old guy had no stain and it was finished with a powdered stinky mix called Deft that we made up in the wood shop. Kid used to sniff that to get high in class.

[@StalwartFixer]

Could you tell us specifically which polyurethane you used for your formers?

[@MIKROWAVE1]

Nothing special. Minwax semi gloss! I worked for a company that rebuilt IF transformers, variable inductors and RF toroids in college as a Co-Op student. There we used very special Hi-Q varnish with proscribed baking and the Q was measured at each step. Those were for military radios. This ain't that!

[@StalwartFixer]

Thanks for responding.

[@graplingurty]

Very very nice! KC0ZQB said that

[@logger90]

hi !! very nice !!!

[@TinnTinn72]

Nice!!!

[@Jomatsch]

When building a loose-coupler or variometer/ variocoupler what inductance do you prefer for the primary and secondary? Sometimes you see 240/240uh, other times it's maybe 240/150 uh. Always wondered which way to go and why.

[@MIKROWAVE1]

There is no best answer because of your unknown antenna situation. Hence the variable slider and tapped secondary affords complete adjustability on each side.

[@Jomatsch]

Thank you for your reply. @@MIKROWAVE1

[@joel6221]

@26:38 Can we get details on creating a slider?

[@MIKROWAVE1]

Nested square Brass Tubing can be had at hobby shops and sites. K&S Brass is a good start.

[@estpst]

how do you attach the primary coil to the end pieces?

[@MIKROWAVE1]

In the originals, typically the end pieces were turned so you could make an undercut that would allow it to slip into the tube. three small screws were then used to keep it in place. In the modern one I just glued them after testing!

[@BonsaiBrandy]

Would there be any benefit to putting a variable capacitor before the primary coil?

[@MIKROWAVE1]

Experiment ! The primary on the loose coupler is useful as an antenna tuning element. A cap in series with the coil can make a series tuned circuit to select a single frequency. In parallel you get a double tuned circuit but you would need a second slider for the antenna .

[@robbie8825]

You should do tutorial videos on Morse code!!!

[@kennynvake4hve584]

Does it matter what diameter the wire is...I realize the smaller it is the more turns you can get on the spool.

[@MIKROWAVE1]

Yes it will effect the inductance according to the wire diameter, especially on a close wound solenoid coil. Fortunately the formula takes length into consideration and this automatically adjusts the answer for wire diameter. It's all approximate, but in general the inductance goes down and the coil would have to be longer with thicker wire, all other things being equal.

[@MIKROWAVE1]

Your SDR will be so happy. Seriously, putting some selectivity and matching in front of a broadband SDR, is a great starting place for better performance.

[@attilarivera]

👏👏👏👏👏👏👏👏👏👏👏👏

[@andrzejpl9897]

👍👍👍

[@chrismosley409]

is the primary resting on the baseboard or is there a small gap?

[@MIKROWAVE1]

+Chris Mosley Hi Chris, The Primary coil is suspended above the base and I just glued it to the front and back wood. Some people make a ring or a half moon shape glued to the ends that suspend the coil from the inside and keep it from moving up or down.

[@bassdowg]

I have an mfj Random wire length Matching Tuner that use to match my xnceiver's input/output to my outside mounted Covert antenna sys. Can i use that mfj tuner also ??? 73s

[@MIKROWAVE1]

Typical HF Tuners work fine above 3 MHz.

[@bassdowg]

MIKROWAVE1 tyvm much Sir, watching your series on xtal radio rcvrs really IS A Pleasure and a Great Tip on Faraday shields, i added a faraday shield on my home brew matching tuner that i use with an NVIS celing mounted Ant. And quickly Noticed that it is now easier to Tune and obtain a match and greatly eliminated "Hand" capacitance whn i operate the Knobs of d var. capacitors. Great videos Sir TYVM !!!

[@chrismosley409]

ok. thanks.

[@stephenwilliams5201]

Have one given to me by a elmer. At w8ft it's date of manufacture may of 1921 I follow foot ball games on a 97 year old radio. Hope to see it's 100 th year of service de kv4li PS it's name plate is Toledo duck

[@chrismosley409]

thanks. is the amount of turns just a matter of experimenting? I used a 1 and a quarter inch wooden dowel with 160 turns of 26 guage magnet wire for my crystal radio. is that too much for the broadcast band? it seemed to work fine with this huge 3 gang variable but when I switched to a smaller one I hardly got any volume at all.

[@MIKROWAVE1]

Yes! All Coil Charts represent is a starting point. Too many variables to say exactly how many turns!

[@matthiaswilhelm9813]

PS. The opened End of the Coil ist not so good🐤🐤🐤🐒🙀Open freewaves in the coil...make the Slider Hifrequenzy Just a little Bit Bad and poor.

[@ingussilins6330]

I have convert loose coupler to LW variometer and add goniometer coil

[@MIKROWAVE1]

A Goniometer is the Ne Plus Ultra of low frequency direction finding in the teens and 1920's and it allows you to steer your antennas without physically moving them. Think multiple fixed verticals or crossed loops.

[@lomgshorts3]

I hope you didn't take the tuner knob out of a National Receiver. That would be a crime against a collector radio that Hams search for intact with no mods. Better than Collins receivers any day.

[@GENESUTUBE69]

I JUST DO NOT GET IT. WHAT IS THE FASINATION WITH CRYSTAL SETS . THEY ARE A THING OF THE PAST. TODAY WE HAVE SUPER HETRODYNE RADIOS WITH GREAT SELECTIVITY AND SENSITIVITY AND QUALTY SOUND AND VOLUME. LET'S CONCENTRATE ON BRINGING BACK THE HORSE DRAWN CARRIAGE.