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 Post subject: Norm's 12K5 Regen
PostPosted: Dec Thu 13, 2007 2:34 am 
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I got Norms schematic today so I thought I'd post it.

Image

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 Post subject:
PostPosted: Dec Fri 14, 2007 2:56 am 
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Hi Norm

What size coil form do you recommend???

I have 100/25 turn coils I wound for a 6BM8 xmitter, I'll prob start by removing 23 turns... :lol: I hate windin'... Also have a 12K5, ought to be a "piece O cake" to build... Me getting it to operate, now that's a different story...

Tom


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 Post subject:
PostPosted: Dec Fri 14, 2007 4:04 am 
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Hi Tom

Any coil made for the broadcast band will work. Just add a couple turns for the tickler. I wouldn't remove your 25 turn coil. You might want to use it for antenna and ground input?

Won't have a problem if you are familar with regen radios. If not familar will take a few minutes tuning.

Suggest using a very low value pot for R1. The type used as speaker fader control in car radios will be ok.

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 Post subject:
PostPosted: Dec Fri 14, 2007 4:20 am 
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OK Norm

I've come up with a fairly different form anyway, so I'm going to wind... The 12K5 tests good, I'm on the way...

Hopefully I can make it work, I wanna take pictures... :mrgreen:

Tom


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 Post subject:
PostPosted: Dec Fri 14, 2007 4:52 am 
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Tom,

Looking forward to pictures.

Norm,

Whats the purpose of the .022 speaker cap in this circuit?



Kevin


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 Post subject:
PostPosted: Dec Fri 14, 2007 5:43 am 
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the .022 ufd cap by-passes the RF sig to ground ( b+) while the audio sig is passed by the transformer to the next stage.

RCW

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 Post subject:
PostPosted: Mar Sat 07, 2009 3:22 am 
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Location: Orlando, Florida 32803
A couple questions:
At what voltages should the caps be rated at?
Wattage for the resistor?
Could I use a different coil to receive SW?
Thanks,
-Shane-


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 Post subject:
PostPosted: Mar Sat 07, 2009 9:51 pm 
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Quote:
A couple questions:
At what voltages should the caps be rated at?


Since it uses a 12 V supply, 16 V or 25 V caps should be fine.

Quote:
Wattage for the resistor?


The resistor doesn't dissipate any power so a 1/4 W or 1/2W is fine; whatever you have handy.


Quote:
Could I use a different coil to receive SW?


Yes. You would need fewer turns, of course. You might try about 40 turns with a 6 to 6 turn tickler coil. Experiment! That's where the fun comes in!

Rich


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 Post subject:
PostPosted: Mar Sun 08, 2009 8:15 pm 
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Thanks Rich!


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 Post subject:
PostPosted: Mar Sun 08, 2009 8:21 pm 
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Sorry, I meant to write "6 to 8 " turns for the tickler winding.

Rich


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 Post subject:
PostPosted: Mar Mon 09, 2009 1:47 am 
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I would like to build this radio using a variable tickler instead of the reostat. I am having trouble finding a 12K5 tube though. It seems to be a bit scarce.


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 Post subject:
PostPosted: Mar Mon 09, 2009 2:56 am 
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I got mine off of ebay, Probably paid too much but oh well. There were like 4-5 on there the other day. The one I bought was $10 incl. shipping.
Good luck.

-Shane-


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 Post subject:
PostPosted: Mar Mon 09, 2009 3:23 am 
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Radio Daze and likely the other suppliers have 12K5s for $3...

Tom


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 Post subject:
PostPosted: Mar Mon 09, 2009 3:34 am 
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I went to Tubes And More and they didn't have them so I immediately turned to ebay, Forgot about Radio Daze.....DOH!

On another note I was thinking of making both BC and SW coils complete with their own ticklers for this, and then wiring them in so I can just flip a switch/s depending on which band I want. Based on Rich's earlier post I should be able to do this w/ o mods to the rest of the circuit right?

-Shane-


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 Post subject:
PostPosted: Mar Sat 21, 2009 2:46 am 
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Do you wind the tickler around the broadcast coil or above?


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 Post subject:
PostPosted: Mar Sat 21, 2009 3:05 am 
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Location: Tustin,CA
The tickler/feedback winding can be separated from the main coil by about 1/8" if you're winding it on a standard plug-in coil form. In practice, it can be wound right around the main coil... Although 6-8 turns will suffice, anything in the area of 10-45 turns will work as the setting of the regen control will control the feedback.
Dave - WA6VVL


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 Post subject:
PostPosted: Mar Sat 21, 2009 3:16 am 
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Location: Livermore, CA
Hi

Like mentioned tickler can be wound close to the tuning coil. With this tube tickler only needs a turn or two. I wrote two turns but found even 1 was enough when I built the circuit.

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 Post subject:
PostPosted: Mar Sat 21, 2009 3:32 am 
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Here's a pict of the one I built, you can see the tickler coil waving in the breeze...

Image

Tom


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 Post subject:
PostPosted: Mar Sat 21, 2009 6:46 pm 
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Could I use the audio transformer from my junk Westinghouse WR-179(5 tube AMer)? It looks the same as the one pictured but I don't know the specs.


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 Post subject:
PostPosted: Mar Sat 21, 2009 7:25 pm 
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That was the 1st transformer I tried from a battery portable, wasn't very happy with it or one from a AA5...

Read through my posts in this thread, where I talk about the transformers I tried...



Comments just after the picture and scope waveforms have the most info on transformers...

Tom


Last edited by 35Z5 on Apr Mon 18, 2011 6:33 pm, edited 1 time in total.

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