RF LINEAR AMPLIFIER

Low Noise Rf Amplifier

2010-01-11T01:22:00.000-08:00

This amplifier was designed to improve an existing receiver by replacing the original r.f. stage. The circuit utilizes a Low Noise Rf Amplifier , has a dynamic range of 100 dB , and exhibit low intermodulation distortion.

Incorporation of the Low Noise Rf Amplifier into an existing receiver obviously varies, depending on the receiver, and can not be discussed in detail but must be left to the individual construction

800w Mosfet Rf Linear Amplifier using IXYS

2009-04-27T09:04:00.000-07:00

By : Ir Eliza Sukiman MM MA

This Mosfet Rf Amplifier will give you 800w output. The PA stage consists of four push-pull modules ,with splitter and combiner. each comprising a pair of IXYS 82N25P MOSFET devices. Each push pull is rated Po = 200W only. They have an "on resistance" of 0.35 Ohms , will dissipate about 500W each. V dss Drain Source Voltage 250 , Id Continuous Drain Current 82 A , C iss input Capacitance 4800pF,Output Capacitance 900pF .

The Mosfet Rf Amplifier produce 800w from 24V on 80 , 500w on 160 and 40 M .

The circuit work with four push-pull modules ,combiner and splitter The amp as shown needs 75W of drive for full output. The splitter wound on a small tubing or toroid transformer with about one turn pri. and two turns sec. The Combiner made from large ferrite tubes . The Switching power supply is 24 Volts 100 A.

The standing current for this Amp.200ma for each mosfet.

Mosfet Rf Amplfier should be set to about 400 ma by adjusting the 10k Ohm pot carefully! Remember these FETs can really draw some current!, to see . . . schematic

1kw Mosfet Rf Amplifier

2008-12-29T05:28:00.000-08:00

Ir Eliza Sukiman MM MA

YB 0 BAJ Indonesian Amateur Radio Station

This is my 1kw Mosfet Rf Amplifier. The MosFets are IRF 450 . They have an "on resistance" of 0.31 Ohms , will dissipate about 190W each. Vdss Drain Source Voltage 500 , Id Continuous Drain Current 14 A , Ciss input Capacitance 2000pF,Output Capacitance 300pF I have used them in my base station and they produce a good 1000w from 70V on 80 , 600w on 160 and 40 M .

see . . . . schematic

600w Mosfet Rf Linear Amplifier

2008-06-17T08:53:00.000-07:00

Ir Eliza Sukiman MM MA

YB 0 BAJ Indonesian Amateur Radio Station

This is my base station of MosFet Rf Amplifier . The MosFets are APT5020BN ,I have used them in my base station and they produce a good 600w from 36V on 160 and 80,and 400w on 7 Mhz. , I've had 600w out of four at 36V on 160 with a one turn primary / four secondary on the output transformer. (Tubing Transformer).
The circuit is basically the same but this is two devices with combiner on each side of the push-pull. The golden rule is to use a fet capable of withstanding three times your maximum supply voltage.

lets see . . . Schematic

New power-MosFets coming out every week or so, look for ones with a low Rds-on and high power dissipation. The main drawback is the high gate capacitance, several thousand pF, which makes them hard to drive above 7MHz. Check out IRF , IXYS and APT ( FET manufacturers)

300w Rf Amplifier using low priced Mosfet

2008-05-27T07:57:00.000-07:00

by Ir Eliza Sukiman MM MA
YB 0 BAJ Indonesian Amateur Radio station

I have read Rf Amplifier Circuit using mosfets on the ARRL Handbook 2002. The amplifier used a pair of Motorola IRF510 transistors to generate 5 or 6 watts of peak envelope power from a 48V supply and operated within the frequency spectrum of 1.8 to 28 MHz.

It might be of further interest to describe a higher power version of a linear amplifier which I had reason to design, using two IRFP 150. The Circuit can deliver a power off 250w at 1.8 MHz, 300w at 3.5 MHz and 200w at 7 MHz with 36 v . The IRF150 transistors used were the International Rectifier (IR) .

see . . . Schematic