A simple experimence (more simple than I expected)
I am not a electronic engeneer, but
Pardon Qiaozhi, the efect you refer about glowing incrase when you increase the antena lenght is induced by antena capacitance, once you feed the leds with ac current.
Once the antena capacitance increase, the antena will be more tunned and irradiate (dissipate) more common radio electromagnetic energy! until you reach some multiple of wave lenght. (if you decrease the ac frequence you will see less glowing on the led - higher the frequency higher capacitance you need to stay the antena tunned -> more lenght of wiring you need!) It is basic.
If you feed the led with DC or very low frequency you would not glow the led.
Greetings and wish success to you
Francisco Xavier
I am not a electronic engeneer, but
Pardon Qiaozhi, the efect you refer about glowing incrase when you increase the antena lenght is induced by antena capacitance, once you feed the leds with ac current.
Once the antena capacitance increase, the antena will be more tunned and irradiate (dissipate) more common radio electromagnetic energy! until you reach some multiple of wave lenght. (if you decrease the ac frequence you will see less glowing on the led - higher the frequency higher capacitance you need to stay the antena tunned -> more lenght of wiring you need!) It is basic.
If you feed the led with DC or very low frequency you would not glow the led.
Greetings and wish success to you
Francisco Xavier

Perhaps you're just playing along with the game.
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