Simple preamp for ADSB using BFP420

This simple circuit uses a cheap BFP420 which is available at Reichelt.
Everything including SMA and F connector are also availble there. Total costs less than 4 Euro.



Note: Resistor is 22K and not 6K8 as shown
(Thanks to Renato for pointing out that the BFP420 will suffer with 6K8, 22K gives typ less than 20mA Ic)
Cut a piece of PCB to size, remove two stripes of copper with a cutter to make a copper line down the middle. Cut two times a break into the line for transistor and capacitor.


Place transistor and input capacitor.
Then place coil and decoupling cap above transistor.

Cap and Coil

Finally add SMA connector and base resistor.

SMA and Cap

Power with 5 volts on F connector.
Voila, you have very cheap but good and solid 20dB 17.5dB (with 22K resistor) gain!

Amp gain