Light LED from RF

[C2]

I want to install an LED in my tuner to light up on transmit, but I don't want to supply external power to the tuner.

Any ideas on a circuit that will let me tap the RF as a power source without affecting the RF circuit?

I have some basic 3V LEDs, if these will work.

 

[Captain Kilowatt]

The problem I see is providing enough voltage and current to sustain illumination of the LED. Also brightness will be very dependant on power output,SWR,reactance voltages present, etc. However, you could wind a torroid with lots of turns of really small wire and slip in over the feedline to tap the RF.Don't worry about RF being AC and the LED's requiring DC.If you can get enough pickup it should work.It won't work real well but it should work.A neon bulb would be MUCH better and easier to light up BTW.

 

[mechanic]

Nicola Tesla did this a hundred years ago but he was using very high voltages and I guess the lamps or what ever they were, became illuminated in the near field of the transmitter.
To do this with a much lower power transmitter of say hundred watts or so you would have to build a resonant tank circuit so some of the power would transfer into and depending what the voltage requirements of the LEDs are, you would have to build the tank circuit with enough potential to power it. :mellow:
I would imagine that the tank circuit to relay the power to the LEDs would be fluctuating in voltage level as it would be following the current and voltages of the RF output. This would make the LED vary in brightness all the time.
The circuit would also take power from the RF output but not too large. You might be better off using some sort of florescence bulb or maybe neon. :blink:

mechanic (aka KB8DNS)