I do not know why you cannot buy common capacitor values. Farnell (now called Element14) has a warehouse in India:
**broken link removed**
I use metalized plastic EPCOS film capacitors for 1nF to 1uF and they have a tolerance of 5%.
The total input resistance of the oscillator of the MOD4 transmitter is about 22.7k ohms so a 330nF coupling capacitor produces a cutoff frequency of 21Hz, 220nF makes 32Hz, 150nF makes 47Hz and 100nF makes 71Hz.
What is "an output coupling capacitor" used for?
**broken link removed**
I use metalized plastic EPCOS film capacitors for 1nF to 1uF and they have a tolerance of 5%.
The total input resistance of the oscillator of the MOD4 transmitter is about 22.7k ohms so a 330nF coupling capacitor produces a cutoff frequency of 21Hz, 220nF makes 32Hz, 150nF makes 47Hz and 100nF makes 71Hz.
What is "an output coupling capacitor" used for?