I have finally built an FM transmitter.
Previsouly I have built an AM transmitter but it never worked right, only very short distance.
http://cappels.org/dproj/FMXMTR/fmxmtr.htm
The design is somehow finicky, and does not work like shown. Adjustable resistor for the 330 Ohms, and 1K Ohms are essential.
As well, you need to tap the antenna with a gimmick capacitor.
-It only works at the very end of the FM scale
-There is still some noise contained. But with the indended frequency adjuster, it can be reduced.
Ideally if the frequency is set right, the circuit is sensible against tapping with a screwdriver. You will hear microphonic noise.
I have tested 10m distance so far!
- demo video
Previsouly I have built an AM transmitter but it never worked right, only very short distance.
http://cappels.org/dproj/FMXMTR/fmxmtr.htm
The design is somehow finicky, and does not work like shown. Adjustable resistor for the 330 Ohms, and 1K Ohms are essential.
As well, you need to tap the antenna with a gimmick capacitor.
-It only works at the very end of the FM scale
-There is still some noise contained. But with the indended frequency adjuster, it can be reduced.
Ideally if the frequency is set right, the circuit is sensible against tapping with a screwdriver. You will hear microphonic noise.
I have tested 10m distance so far!
