RF Amplifier For QRP
Eliza Sukiman. ( YB0BAJ )
This RF Amplfier For QPR has made from low price Mosfets . The MosFets are WO12L54F or any mosfet like IRF250,IRF450 can use for these .
The circuit is a Push Pull with 2 pcs and two band Low pass Filter for 3,5 Mhz and 7 Mhz.
The Rf Amplifier For QRP as shown needs 1W only of drive for full output.
The input transformer T1 is wound on a
small tubing transformer with about one turn pri. and three turns sec. The
thermal sensor contact with the heat sink and well decoupled to prevent Rf pick
up .The output transformer uses large ferrite tubes . The primary is one
turn of tubing transformer and the secondary is 3 turns of thinner multi strand
stuff .
The power supply for this Rf Amplifier doesn't
need regulating and 12v enought for full power output 50w
The standing current should be set to
about 200 ma by adjusting the 10k Ohm pot . you can see . . . schematic
