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PostPosted: Mar Wed 25, 2009 9:04 pm 
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Will a 25 ohm rheostat from radioshack work? http://www.radioshack.com/product/index ... Id=2062299


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PostPosted: Mar Wed 25, 2009 9:44 pm 
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In the write up on page one, Norm says anything between 10 & 100 ohm will work... I have a 10 ohm in mine and was thinking of trying something a little higher to see how it effects the regen operation...

Tom


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PostPosted: Mar Wed 25, 2009 10:15 pm 
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What is the value on the coil?(I am going to wind my coil on a film canister so I need the value to put in the coil calculator)

Edit: I wound a coil that works


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PostPosted: Mar Fri 27, 2009 1:41 am 
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If it helps, I have approx 95-100 turns on a 35mm film container...

Tom


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PostPosted: Mar Fri 27, 2009 4:36 am 
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As a benchmark, the Knight Kit Ocean Hopper uses a dual-gang tuning cap with a total of 620uuf to cover the entire AM BCB. The inductance of the coil is 136uHy (73 turns on a 1-1/4" dia). Keep in mind that early regens used a "standard" 140uuf tuning cap that required TWO coils to cover the entire AM BCB (typically 115uHy and 412uHy respectively).
Dave - WA6VVL


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PostPosted: Mar Fri 27, 2009 8:28 pm 
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I wound a 350uHy coil. 133 turns on a film canister with 30GA wire and I am using a 365 pf variable capacitor.

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PostPosted: Apr Sat 25, 2009 8:36 pm 
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Well I built mine and it works! I have to hook it up to the computer mic to hear anything though. Hooking it up to a speaker is very faint. I am using an output trans from a radio with a 50L6 output tube which I realize is not optimal, just using it till I can find something better.
I have a question though, what sort of lytic do I use to reduce hum?
I tried a 30mfd @160v and the filament won't glow with it wired in (the smallest I have at the moment).
-Shane-


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PostPosted: May Mon 04, 2009 2:15 am 
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If you are using a power supply for the b+ dont. use one of those N batteries. I am not looking at the schematic but I think you can use ac on the filament because it has a cathode.

Edit: never mind Im wrong about the filament with ac. Try two caps.

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PostPosted: May Mon 04, 2009 2:44 am 
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I used a '60s car radio p/s to power mine, and it also performed with no issue on a 12v DC @1A wall wort...

Tom


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PostPosted: Apr Mon 05, 2010 2:15 am 
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Can someone tell me if when you role the wire on the coil form does it matter if the wires lay on top of each other ? Or do they have to lay next to each other ?

Thanks,
Carlos


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PostPosted: Apr Mon 05, 2010 10:47 am 
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Side by side.
Curt

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PostPosted: Apr Mon 05, 2010 6:26 pm 
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The antenna coils I see in my AA5 radios have the wires on top of each other, just curious as to why that is ?

Thanks and forgive my ignorance, I should just try it out myself to see what happens if I wrap the coils with one wire on top of the other.

Carlos


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PostPosted: Apr Mon 05, 2010 7:05 pm 
Silent Key

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Maybe I am misunderstanding you? But if you can wrap the magnet wire into a coil with one turn on top of another, you are a greater person than I am!
Curt

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PostPosted: Apr Mon 05, 2010 7:27 pm 
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Below is a picture of a pill bottle that i am using as a coil form to the right of the picture you can see where each wire is next to each other and towards the left you can see where all the wires are piled up on each other.

Do the wires have to be laid out next to each other or can they go on top of each other when I wind the coil ?

Carlos


Image


Last edited by boxjoint on May Wed 12, 2010 6:36 am, edited 1 time in total.

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PostPosted: Apr Mon 05, 2010 7:44 pm 
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There are more than 6 answers:

With 1 coil, you have 3 "usual" ways of winding it.

1) you start at one end, and very neatly, go to the other end of your coil form, 1 time. You may adjust inductance by making a space between each winding too in doing this. <== This is what Curt said originally, the wire is laid side by side, neat across in one layer I do believe.

2) you can do what I am going to do for a coil soon, and make a 'multi layer' coil. On my 1.25" form, I will go neatly one end over 100 turns nice and smooth, then I comeback over-top that first layer with 100 turns nice and smooth, then once more over nice and smooth 43 turns. This gives me 989uH I believe.

3) Scatter Wound. Same as taking your hand and just going around a finger or three how ever many turns are needed. Jack showed a 3ish mH coil as 300 turns scatter wound around about an inch in diameter eraser. See this thread http://antiqueradios.com/forums/viewtop ... &start=220

Scatter winding affects wire to wire capacitance, I am not sure how but that is the difference between that approach and neatly winding. There is another winding method that is multi layer that you don't do by hand, but use a winding machine for that is also done because of the effect of capacitance. I think it is diminished in this method.

This is a cool tool, and there is a member of ARF that did this, he has a thread on his building one if you search:

http://www.youtube.com/watch?v=FIOocMoRsYQ


2 (or more) Coils have three forms of winding.

1) each "coil" physically separated by a space from each other, this is called a loosely coupled coil.

2) each coils wire used at the same time to be wrapped is called bi-filler winding. This is tightly coupled.


3) wind one coil, then wind the second ontop of the first. This is tightly coupled.

I believe the difference between 2 and 3 is the coil to coil capacitance. I also think when you are doing 2 or more coils on a single form, you would not scatter wind.

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Last edited by KeeperOfTheGood on Apr Mon 05, 2010 7:54 pm, edited 2 times in total.

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PostPosted: Apr Mon 05, 2010 7:51 pm 
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Now that was an awesome explanation !! Thank you very much !!

Carlos


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PostPosted: Apr Mon 05, 2010 7:56 pm 
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8) Carlos, all is good. I may edit my post another time or two LOL a couple typos and some links too. Maybe need to fix the info a bit as well, but I think the basses of an answer is there for you.

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PostPosted: Apr Mon 05, 2010 8:44 pm 
Silent Key

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OK, I see what you mean now. We always called that scramble wound. But one turn on top of another would make a spirial type of coil.
Curt

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PostPosted: Apr Wed 07, 2010 4:02 am 
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Avoid multilayer coils in tuning tanks when you need wide tuning range. Their parasitic capacitance is a lot higher than a plain single layer coil. If you absolutely want or need multilayer coil use either basket or "universal" winding types.


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PostPosted: May Wed 12, 2010 6:26 am 
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I built a very similar version of this last fall, it's a great little tube. On a lark, I re-arranged the pinout to match a 12BL6 I had on hand and immediately noticed that the K5 has a far brassier, tinnier sound than the BL6. Beats me why.

I had to use 1100-ohm headphones on mine, though, b/c at the time I didn't have an audio xformer.

Thanks for the circuit!


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