Tuesday, May 27, 2008

300w Rf Amplifier using low priced Mosfet

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 ,WO12L54F , or other . 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  the International Rectifier (IR) .

see . . . Schematic

See Youtube 300w ...  Click Here

See Youtube  600w  ...  Click Here

See Youtube 800w ... Click Here


Harya Sidharta said...

Salam kenal,
Web site yg menarik untuk media sharing bagi homebrewer :

Sangat menarik melihat hasil experiment anda :

Saya tertarik u/ mempelajari dan mungkin mencobanya.

Mohon di tampilkan data lengkap skema RF 180 Watt :

- Skema
- Komponen
- Step2 merakitnya

Info ketersediaan komponen di lokalan indonesia seperti Transformer dan Toroidnya


Ir.Eliza Sukiman.MM.MA said...

skema menyusul , step merakit nya akan dibuat pada halaman terpisah,pada prinsipnya tidak sulit dan menggunakan kompunen2 yg ada di toko2 elektronik umum,juga toroid nya bukan sesuatu yg khusus , tujuan nya supaya murah meriah ok . . .

tzik said...


Problem with 500w AM Linear with mosfet IRFP360

Hi. I have construct this linear 500w rms (2kw pep) (50ohm) with 12 mosfet irfp360, http://tzitzikas.webs.com/linear500w.jpg

The manufacturer and other radio amateurs from a forum have construct it successfylly.
The manufacturer tells that the linear requires only 2 watts r.f driving power for full 500w output r.f
power. The supply is 70-110vdc and for maximum power with 110vdc tha current is 13A (without am modulation).
Without driving power, we must adjust the current at 200mA (when the linear is cold).
My problem is this: When i tried to adjust the current at 200mA without driving power, when the current close to
160mA (by tuning the variable resistance 5Kohm) suddenly the current takes the value 3A and some smoke comes out
from the input transformer.

some photos from my linear and pll here:

With 2w input driving power from my pll and supply at 110vdc, and 150mA current without input r.f power, the output power was

only 60w and the current was only 3,5A without modulation.
Witch do you think is the problem? Thank you very much and sorry for my English.
my e-mail is tzitzikas_ee(at)yahoo.com

Ir.Eliza Sukiman.MM.MA said...

hi , i think you must change bias resistor 10 k and then you turn carefully for 100 or 200 ma with no drive.