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Here is a simple one, gang! My Crystal Clear radio is built
around a coil that was made for me by Master Woodworker
Tom Kipgen. Most of my designer radios
are built around one central component. The rest of the radio follows along.
This beautiful coil is wound on a clear form. Since the coil is space wound
(small distance between the windings), the visual effect is greater, not to mention
the coil Q being greater.
The schematic is shown below. The circuit is much like several of my other
sets. One difference is the use of a link switch to add capacitance to the
main tuning capacitor. I had two look alike capacitors but the capacitance was
only 280 pf. Not enough to tune the entire band. So I added 250 pf to the main
capacitor that can be switched in to tune the bottom of the band. The capacitor
happened to already be attached to the capacitor. No doubt that this was a grid
leak capacitor for an old tube radio.
I used two pieces of plexiglas 9 x 7 inches (23,9 x 17,75 cm) separated
by four ceramic insulators. As you might have guessed, all this is from my
junk box. Having the two pieces of plexiglas gives the radio a more rigid
construction. If I had omitted the bottom piece, the plexiglas might someday
break. The second piece does add nice visual interest too.
Since I first built this radio, I felt it was missing something.
Most of the parts are old time or could have been. (Not sure if they
had plexiglas back in the old days). The germanium diode came around during
World War II, so that had to go. In it's place there is a galena rock and
a "catwhisker" probe. I left the original hardware on the detector area,
so one could switch back to a diode.
This is not a performance radio. No litz, old type capacitors with
phenolic insulators and no audio transformer. It still sounds good and I can
pick up several stations during the daytime and lots at night. This is a fun
radio and something that will look nice on my shelf (and maybe your shelf).
73 and good crystal DX. Dave - N2DS
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