Antena Activa FM - dudas.

#1
Amigos, me gustaría saber cuál es el valor del ideal inductor para el proyecto adelante, con el fin de trabajar en FM (87-108 MHz).
El texto menciona sólo AM y SW.
Gracias.




Active Antenna for AM/FM/SW:
This simple little circuit can be used for AM, FM, and Shortwave(SW). On the shortwave band this active antenna is comparable to a 20 to 30 foot wire antenna. It is further more designed to be used on receivers that use untuned wire antennas, such as inexpensive units and car radios.

Parts List:
R1 = 1M C1 = 470pF C2 = 470pF L1 = 20uH to 470uH (see text) Q1 = MPF102, 2N4416, or NTE451
L1 can be selected for the application. A 470uH coil works on lower frequencies and lie in AM, for shortwave try a 20uH coil. The KIT is supplied with a value whatever is available up to 500uH. The color code for L1 is generally yellow-violet-brown for a 470uH type but still this can vary by the type of inductor.
This unit can be powered by a 9 volt alkaline battery. If a power supply is used, bypass the power supply with a 0.04uF capacitor to prevent noise pickup. The antenna used on this circuit is a standard 18-inch telescoping type, but a thick piece of copper, bus-bar, or piano wire will also work fine.
The heart of this circuit is Q1, a JFET-N-Channel, UHF/VHF amplifier in a TO-92 case. Although many different types of FET's may be used--such as the MPF102, or the 2N4416--bear in mind that the overall high-frequency response is set by the characteristics of the FET amplifier. The direct replacement for the MPF102 is the NTE451. Second runner up is the 2N4416. Output is taken from jack J1 and run to the antenna-input of your receiver. Although this little circuit can easily be mounted on a piece of vero-board, I have supplied the printed circuit board and layout diagram if you wish to make your own.

http://www.sentex.ca/~mec1995/circ/activant.html
 
#2
¿Que problemas y que beneficios podría dar este circuito en su funcionamiento?
Lo pregunto porque se ve muy sencillo
 
#4
Tiene buena pinta la pena es que faltan valores de algunos componentes.
Respecto al amplificador del que trata este tema, pues hoy hice una PCB y lo probé tanto en un receptor FM como en banda aérea, dando como resultado la escucha de nuevas emisoras.
Es decir parece que funciona.
El problema que he visto es que le he tenido que poner en serie con la alimentación ( + ) una resistencia de 100 ohmios porque al FET no quemaba ACHICHARRABA es mas me di cuenta porque me queme tanto que me a salido una ampolla en el dedo, y lo increíble es que sigue funcionando. (desconecte rapido )
 

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