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