How to combine RF power amplifier output
I have 10 500w Rf power amplifier for my FM tranmistter . Here I want to know how can I combine these 10 500w power amplifier output to total 5000w . Please give me the detailed working principle .
Regards
Aneesh
Ensure all of them are 50 ohm terminated so they can be cascaded, but as you cascade more the power increase and question here arises weather the transistor in the amplifier sustain that much high input? e.g. your final or 10th stage amplifier in cascaded configuration will have 4500 W at its input !
Cascaded is not fit for this.
Use some combiner, such 2-port ferrite combiner, take care of its max rating power, and calculate the loss.
Maybe you can only have 4600W maximumally.
Why would you need such a powerful amplifier for the commercial 100Mhz band? Pirate radio?
If you ever manage to parallel these ten amplifiers, you must make sure that the amplifiers RF is co-phased. This means that you will have to equalise all paths from the local oscillator to PA outputs. The phase shift might change with temperature, so you might need an automatic system.
Frank
