Circuit to detect the antenna has been attached.

[angy]

I am looking for a solution in which when I attach the antenna then only my circuits gets power ON.
One of the idea i was looking was to use a contact switch.When i attach antenna a contact is made in the contact switch and voltage through contact switch drives a relay .When the relay is energies through its contact i get 24V/4A to power on my circuit.If anyone has any other ideas kindly share it.

 

[KlausST]

Hi,

Your post isn't very descriptive.
Is it an antenna on a house, a car, a RC car, a cellular phone?

What size is the antenna and holder? Is it in house or outside? What climatic parameters?
***
Mechanically moved contacts.
Magnet and reed relay? Magnet and semiconductor sensor. Weight sensor, optical sensors, electrical sensing of L C resonator?

Klaus

 

[D.A.(Tony)Stewart]

If your antenna had a built in resistor to ground, say 10k, it would be simple to have a 1~10M pullup and Cap for low current to activate a P-ch MOSFET high side switch to de-activate the circuit, then activate when antenna 10K to ground without degrading the RF.

PC's use the same method to detect a speaker connected (<100 Ohm) and video port active with 75 Ohm termination on signals.

 

[angy]

If your antenna had a built in resistor to ground, say 10k, it would be simple to have a 1~10M pullup and Cap for low current to activate a P-ch MOSFET high side switch to de-activate the circuit, then activate when antenna 10K to ground without degrading the RF.

PC's use the same method to detect a speaker connected (<100 Ohm) and video port active with 75 Ohm termination on signals.

Can you show a circuit diagram for the same

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I will again clarify my requirement I have n type cable when i connect it ,a signal should be generated which tells that cable has been fitted to the chassis . So right now my plan of going forward is with a micro switch
(KW4A-Z3SP200-7260) .