I assembled the above FM transmitter on a breadboard and modified some part values.
my electret microphone is the audio out on my computer coupled through a 4.7uF capacitor. My C1 is omitted. My R1 is 5.6K. I tied a 220pF capacitor across R1. My R2 is 68 ohms. My C3 is 10pF my C2 is 3 - 20pF (sprague GKU18000 I think. and it came from Sayal Electronics) tuned at around 4 - 10pF. My L1 is fixed at 0.1uH. My C4 is 220uF and the supply is 6V.
What I want to do is make my transmission happen at around 109Mhz for a couple of street blocks for a short period of time, as a test.
I am almost successful. I tried tuning the trimmer the smallest amount possible and every time the screwdriver is on it or the trimmer is in the wrong position, my mom complains that her TV has interference. This happens on channel 59 and channel 60 in Ontario, but only to her TV. Her TV is about 3 meters away from my transmitter.
I want to avoid transmitting to the TV.
For now, I will try a smaller cap range.
Can anyone tell me how to reduce the bandwidth or amount of radio space I am using?
I don't want to flood everyone's radio for several blocks. I just want one measley small section for me, and that's it.