In modern radio receivers you can find an interesting KT0936M microcircuit.
What is so interesting about this microcircuit? It is interesting that this DSP radio receiver can receive radio stations ranging from 150 kHz to 108 MHz
No coils are required except for a ferrite antenna for medium and long waves. Power can be supplied at 3.7 Volts.
The range of received frequencies depends on the voltage at pin 10 of the microcircuit. This voltage is set by a voltage divider on two resistors. On my radio receiver board there is a 63 Ohm resistor for receiving FM, and 780 Ohm for receiving medium waves,the 10 kOhm resistor remains If you change the resistance of at least one of the resistors in voltage divider, the received range will change. Instead of a 780 Ohm resistor, I installed a 50 kOhm variable resistor. Now, by changing the resistance of the variable resistor, I can receive FM, then medium and long waves and a section of short waves.As a result, the radio receiver received 88-108 MHz and 530-1600 kHz; after changing the resistor resistance, the receiver began to receive short waves as well.
If you need a specific receiving range, look at the resistor value in the table.
