10-24-2015, 05:58 PM
> Would this coil work to tune the circuit being that the variable capacitor in the 51 circuit tunes the antenna rather than the primary coil, like in a 1 tube regen.
The '51 schematic is goofy it that it looks like tuning condenser is adjusting the coupling of the antenna. But it's just a series tuned with a switch to change the inductance/frequency of the circuit. Regeneration is achieved by moving the feedback coil closed to the antenna coil.
Typically a variocoupler will have three windings. An antenna winding (smallest), the tuned circuit (largest and in parallel with a 365mmfd condenser will resonate at the BC band)and is connected to the grid of the tube though the grid leak, and the tickler or feedback winding ( size wise it's about 25 percent of the tuned circuit) and is connected to the plate of the tube. Phasing is critical if it doesn't oscillate flip the plate and b+ connections
If she would like to build something on primitive side check out pg 12 here:
http://americanradiohistory.com/Archive-...935-03.pdf
The 30 tube could be an 01A or 199 to keep it in the 1920's.
Big fan of regens! Very simple, sensitive, and selective. They just don't like strong signal (overload easily)
Terry
The '51 schematic is goofy it that it looks like tuning condenser is adjusting the coupling of the antenna. But it's just a series tuned with a switch to change the inductance/frequency of the circuit. Regeneration is achieved by moving the feedback coil closed to the antenna coil.
Typically a variocoupler will have three windings. An antenna winding (smallest), the tuned circuit (largest and in parallel with a 365mmfd condenser will resonate at the BC band)and is connected to the grid of the tube though the grid leak, and the tickler or feedback winding ( size wise it's about 25 percent of the tuned circuit) and is connected to the plate of the tube. Phasing is critical if it doesn't oscillate flip the plate and b+ connections
If she would like to build something on primitive side check out pg 12 here:
http://americanradiohistory.com/Archive-...935-03.pdf
The 30 tube could be an 01A or 199 to keep it in the 1920's.
Big fan of regens! Very simple, sensitive, and selective. They just don't like strong signal (overload easily)
Terry
