The Isoscelodyne — Dave's #34 Radio
I have a new box supplier! Still basswood but different shapes. This one is in the shape of an isosceles triangle. As with all smaller box radios, the trick is getting everything to fit properly. It is a good time to put away the alcohol for a while.
The circuit is familiar to all my regular visitors. It is a single coil, dual capacitor type. This gives me a reasonable performing set, enough for me to consider putting the plans on my web site for you.
The coil form is made from 1/16 inch styrene, the same as my Überlitz coils. The diameter is 3-1/2 inches with a 1 inch hub. These forms can be easily made on a scroll saw. There are 53 turns of 40/44 litz wire, with a tap for the diode at 35 turns. The total inductance is nearly 150 µH. The inductance is slightly higher than usual. I wanted a little better tuning at the low end of the band. I believe that this set will tune nearly to 1700 khz, depending on the antenna.
I have to say that this radio went together very well. The coil fit in the top with only a little wood trimming where the edge of the coil touches the wood. The fit is excellent. That way there is no glue or other visible means of support. The triangular panel was easy to cut and work with. It is also 1/16 inch styrene. Styrene melts very easy, so when doing your soldering on the lugs, make sure they are not attached to the panel. You will have a bad meltdown situation. I used three 1/2 inch dowels to attach the panel to the box. The panel is recessed so there would be room for those old time radio knobs.
Looking good if I say so myself. I will enjoy making these radios in my new boxes. Keep looking!
73 and good crystal DX. Dave - N2DS