What is a good design for a low power low pass filter for the 20 meter ham band
and got:
A low pass filter is a circuit that allows low frequency signals to pass through while attenuating high frequency signals. For the 20 meter ham band, which spans from 14.000 MHz to 14.350 MHz, a low pass filter can be designed to attenuate frequencies above 14.350 MHz.
Here is a simple design for a low power low pass filter for the 20 meter ham band:
Determine the cutoff frequency: The cutoff frequency is the frequency at which the filter starts to attenuate signals. For a low pass filter, the cutoff frequency is the highest frequency that the filter allows to pass through. In this case, the cutoff frequency should be set at 14.350 MHz.
Choose the filter topology: A simple topology for a low pass filter is the RC filter, which consists of a resistor and a capacitor. The cutoff frequency of an RC filter can be calculated using the formula f_c = 1 / (2¦ÐRC), where f_c is the cutoff frequency, R is the resistance, and C is the capacitance.
Choose the component values: To achieve a cutoff frequency of 14.350 MHz, we can choose a resistor value of 100 ohms and a capacitor value of 1 nF.
Assemble the filter: Connect the resistor and capacitor in series, with the input signal connected to the resistor and the output signal taken across the capacitor.
This simple RC low pass filter can be easily implemented using through-hole components on a printed circuit board (PCB). The filter can be powered using a low voltage power supply, and it should provide good attenuation of signals above 14.350 MHz while allowing lower frequency signals to pass through.
