Thanks. I will give it a tryUse any fixed cap you have and see what frequency you get.
If you need to move the frequency a little make a "gimmick capacitor" and add it in parallel with your capacitor. Search on the internet, it is made by two pieces of insulated wire.
Genius. ThanksBy twisting a pair of wires, obviously keeping the plastic jacket in place, you could build quite quickly capacitors in the pF range.
Build one, measure it and try with a similar again. You get nice repeatability. You need a little less? just trim it but cutting the top end.
GIMMIC CAPCITOR <----linkgimmick capacitor
Waow. Here is home. I'm learning a lot. ThanksGIMMIC CAPCITOR <----link
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You can also change the frequency by changing the coil. This kind has a "slug" that turns and moves in/out to change the value.
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Another way to change the frequency is to separate the wires a little in the coil. In the picture I tried to show pulling one turn out a little. If you bend one turn 90 degrees it is almost like removing it.
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Thanks for checking it. Can you modify it for me?Your new circuit has problems:
1) It is missing pre-emphasis (high audio frequencies boost) like all FM radio stations have so the sound received will be very muffled since all FM radios have de-emphasis (high audio frequencies cut).
2) Its RF oscillator is missing a voltage regulator so its radio frequency will change as the battery voltage runs down.
3) Its output coil is not tuned so it will transmit harmonics which will interfere with many other communications like ambulance and police radios use.
My FM transmitter circuit fixed these problems.