HAM radio

150 Watt 40m HF amplifier using air ( plastic ) core transformer. My plastic (air) core transformer looks like this... An air core transformer This amplifier is used with  IC-718 on 40m. Power output drops steeply with increasing frequency. It is unusable at 20m 😔 In this experiment four IRFP450  are used in the final stage to get at least 150 Watts on 40m. Another IRFP450 is used as driver. Here is the circuit.........   R1 ... R16 are paralleled to increase wattage rating. Paralleled resistors are drawn with thicker lines.      Values of the resistors are shown on the schematic and are also repeated here .   R1   =  3 || 470R/2W  =   156R6/6W   R2   =  3 || 470R/2W  =   156R6/6W   R3   =  4 || 150R/2W  =   37R5/8W   R4   =  3 ||  3R3/2W   =   1R1/6W ...

This is a partially working signal generator using Si5351 breakout board  and Aduino NANO. Si5351 came as a breakout board with on board 25 mHz crystal. 8 Khz to 160 mHz was marked on it. Only CLK0 was used as output. Si5351 breakout board I don't know how the Si5351 works! So  looked for some predigested  Si5351 code 😊 Found what I was looking for  here Example 4 appeared to be suitable for a simple signal generator.  This is a simple single-file Arduino sketch by  Christoph OE1CGS. This sketch by OE1CGS, is the heart of signal generator sketch. Signal generator sketch   sigGen1.ino and hex file  sigGen1.ino.cpp.hex  are kept on Google Drive. Download sigGen1.ino from Google Drive You may download sigGen1.cpp.hex from Google Drive The hex file was put in a folder and the following command was executed in that folder..  $ /usr/bin/avrdude...

  This amplifier is used with 40m QRP rig and IC-718. Power output drops with increasing frequency. This can be used on 30M for FT8. At 20M power output drops to 4 Watts :-(. At 80M power output was more than 150 Watts on dummy load however it was not used on 80M band. Objective of this project was to use IRFP450 MOSFET in the final stage of a linear amplifier for lower HF, using unregulated power supply. IRF730 MOSFET is used to drive the two IRFP450. Here is the circuit... Some resistors were paralleled to increase wattage. These are drawn with thicker lines. This picture explains how paralleled resistors are shown in the schematic. R1 ... R10 are paralleled resistors. Values of the resistors are shown on the diagram and are repeated here.   R1  =   3 || 470R/2W  =  156R6/6W   R2  =   3 || 470R/2W  =  156R6/6W   R3  =   4 || 150R/2W  =   ...