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I made this FM transmitter from this video (https://youtu.be/joFourugXvs) but it has a very short range (30 cm). Where's my mistake?

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    \$\begingroup\$ Solderless protoboard is a big part of it, plus untrimmed part leads, sloppy-looking coil, long leads to the voltage source, etc. (Assuming you got everything else right.) Try getting a little closer to what the video presents. \$\endgroup\$ – jonk Jun 19 '20 at 21:01
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    \$\begingroup\$ The mistake is in your expectations it seems. \$\endgroup\$ – Andy aka Jun 19 '20 at 21:03
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    \$\begingroup\$ Include the schematic of your circuit, otherwise people won't be able to answer. By the way, high-frequency circuits might not work as expected in a bread board! try using a PCB \$\endgroup\$ – Hamid R. Tanhaei Jun 19 '20 at 21:03
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    \$\begingroup\$ If you are able to make such a ~100 MHz circuit work on a solderless breadbord then I congratulate you as I think that will be first time anyone manages that! Note how the guy in the video uses a very small board so that all connections are short. At 100 MHz every millimeter counts! 1 mm ~1 nH. \$\endgroup\$ – Bimpelrekkie Jun 19 '20 at 21:12
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    \$\begingroup\$ You hear its signal on a FM receiver? Because breadboards add so much stray capacitance, the main oscillating frequency may be much lower than desired...it is possible that you are hearing its 2nd harmonic, which is much weaker than the primary oscillating frequency. \$\endgroup\$ – glen_geek Jun 19 '20 at 23:17

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