How i know ?
Simple because i use transmission ceramic filter 10.7MHz
see post #14
In last schematic you can see output capacitor of 120pF.
I add that 10.7 Mhz ceramic filter with 3 leg to input of my weiss FM demodulator.
So RF signal goes from this 120pF cap to ceramic filter of 10.7Mhz.
And only signal of this frequency (+/- few kilohertz) can pass trough ceramic
filter...right?
Coil in LC tank is with ferite core so i can adjust oscillator to proper frequency.
transistor S9014 is not good for 10.7Mhz oscillator .
One my friend confitm me that.
So i use 2N3904 which is excellent ( use any VHF type) or 9018 or BF199 or C3355.
To prevent any audio leak detector/demodulator and oscillator/signal generator each of them use
separate power supply also as audio amplifier on which is demodulator output connected.
I hope that now is much more clear.
View attachment 45738