- #1
rar0308
- 56
- 0
i'm building fm radio jammer for project for my ee class in physics department.
a circuit is here.
http://www.circuitstoday.com/fm-radio-jammer
i bought the components, soldered on PCB.
it hasn't worked.
an oscilloscope shows sine oscillation even if there is no L and C for tank circuit. i.e. connects wire of both ends which supposed to be connected with L and C.
also it shows different frequency than expected by calculating resonance frequency formula i.e. reciprocal of (2 pi root LC) to the point that it seems what L and C are connected doesn't matter.
i suspect there are some kind of innternal inductance and capacitane.
i'm wondering why mine doesn't work.
I saw that other person made the same circuit and that one worked fine.
i did everything same except i think using different kind of variable capacitor.
i used one in second picture because i can't find first one in my local electronics components store.
difference is that they have different q factor.
is it impossible to make lc oscillator making signal in frequency 100Mhz without high q factor capacitor or there can be other thing i am doing wrong?
also i am almost ignorant of how this ciurcuit works. what books do you recommend to study about this circuit?
a circuit is here.
http://www.circuitstoday.com/fm-radio-jammer
i bought the components, soldered on PCB.
it hasn't worked.
an oscilloscope shows sine oscillation even if there is no L and C for tank circuit. i.e. connects wire of both ends which supposed to be connected with L and C.
also it shows different frequency than expected by calculating resonance frequency formula i.e. reciprocal of (2 pi root LC) to the point that it seems what L and C are connected doesn't matter.
i suspect there are some kind of innternal inductance and capacitane.
i'm wondering why mine doesn't work.
I saw that other person made the same circuit and that one worked fine.
i did everything same except i think using different kind of variable capacitor.
i used one in second picture because i can't find first one in my local electronics components store.
difference is that they have different q factor.
is it impossible to make lc oscillator making signal in frequency 100Mhz without high q factor capacitor or there can be other thing i am doing wrong?
also i am almost ignorant of how this ciurcuit works. what books do you recommend to study about this circuit?