The "Sky King" Solid State Regen Radio

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Sky King
Can you imagine how Hollywood, with its sleaze and perversion, would portray the Sky King show today? Perky little Penny all alone out on the ranch with Uncle Sky. Look at Sky with his firm jaw and his "no nonsense" gaze. He's wearing a holster. He's got a gun to shoot bad people with! Quick, change the channel. It's not politically correct, it's "offensive!" The gun is "triggering!"

I'm glad I grew up in the day when a kid could watch good guys shoot bad guys on TV, and you'd feel really good about it.

I found this picture on Wikipedia. I don't know who the dude on the right is. Let's call him "Tie King" because he has a funny little tie.

You have to wonder as you look at this, where are their other hands? I think Sky King and Tie King are grabbing Penny's butt, which is why she has a funny look on her face. However, if it can be said that Sky King and Tie King are grabbing each other's butts, the show can be deemed "diverse" enough for children to watch.

Back to the radio...
The short wave band (Band 4) didn't work very well.
 
radio coils
The forty meter shortwave band is at the top of the green coil, six turns of wire. It works great for broadcasts but I had to turn the volume all the way up to hear any "hams". A coil of ten turns of 24 gauge wire, space wound on a 1 1/4 inch coil form, covers the same band. When dropped inside the main coil. The difference in the radio's volume is dramatic and it also seemed to make the Morse code more stable. (less warbling.)
 
Radio Coil
regen radio
The little coil now lives inside the big coil and is the new "Band 4".  I hooked it up backwards the first time so I used red and black wire to prevent me from getting the wires mixed up.
Useless control
After using the radio for awhile, it was found that the control above, which coupled the RF amp to the tuning coil, did very little. In series with the 365 pF variable capacitor was a 47pF fixed capacitor, which gave a total of 42pF with the plates fully meshed. It was replaced with a 33pF fixed capacitor, which costs about 20 cents versus the variable cap which costs about 20 dollars!

 
How well does this thing work? I give it a score of "pretty good" but you sometimes have to work at it because it's a regen set. Strong local stations come blasting in like it's a superheterodyne. Tuning in a weak station takes some effort, but that's where the fun comes in.  There are two  "flamethrowers" at 1060 and 1440. We listen to 990, 1180 and 1210. The flamethrowers tend to swamp the dial but you can eliminate them completely with a little effort.

After hearing how well the little coil works on Band 4, I may  make a separate coil for each band in the future.


Making the paper face plate. It had to fit on a single piece of printer paper.

Regen radio schematic
The schematic.
 
LM386
The audio section is a standard LM386 configuration. Notice this is set to "Gain = 200." The gain is set with the 10 uF capacitor across pins 1 and 8.

card table
Here's my temporary card table "workshop" in the kitchen.

 
Bardeen Shockley Brattain 1948
William Shockley, John Bardeen, Mike Simpson and Walter Brattain discuss the principles of the basic circuit while listening to "Coast To Coast AM" with George Noory. They are discussing time travel in this episode of the program. That's amazing! as George would say.

 
Gary's regen radio
Remember Garry, the guy who told me to change the value of the source resistor? He built a similar radio that only has one knob.
He used a stick to control the regeneration. I would like to strangle him. Coincidentally, the date on the battery is my birthday.

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