SLIGHT HELP NEEDED WITH ACTIVE ANTENNA CIRCUIT

[cobra149]

Hi,
please can some one answer wether I could use an axial inductor in this circuit instead of a wound coil
for the required inductance of 20uH ?.
Drawing attached.

Thank you.

View attachment 41462

 

[audioguru2]

If you are anywhere near civilization, what will prevent the untuned circuit from being overloaded by almost every one of the thousands of powerful local signals on many frequencies?

An ordinary half-decent FM tuner tunes its antenna input, then adds AGC to the Jfet to prevent overloading.

 

[cobra149]

@audioguru
Thanks for the reply.
What do you suggest adding to this circuit to improve it ?.
Also what about my original question on Axial inductor instead of air or ferrite wound coil for the 20uH ?.

Regards

 

[audioguru2]

I think the antenna amplifier circuit is very old and might have worked fine long ago when there were not as many powerful radio, TV, taxi cab and cell phone transmitters all over cities.

Now the antenna input must have a tuned circuit and AGC must be used.

I use an 8 turns air-core coil for 100uH on my FM transmitter. 20uH is only a couple of turns for an air-core coil.