Monday, May 25, 2015

RF Amplifier For QRP

Rf Amplifier For QRP

Ir.Eliza Sukiman.MM.MA ( YB0BAJ )

This Rf AmplfierFor 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

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