Too Much Power!

A project log for 2m FSQ Beacon

Sounding beacon for FSQ digital mode on 2m band

scott-braggScott Bragg 04/15/2017 at 13:060 Comments

So the minikits amp is 8W nominal output, 5W safe with a 5mW input. Looking at the I2C code for the clock generator, I can set 2mA output, on a 3.3v device that makes roughly 16mW power. I need to attenuate that input into the amplifier or I will overdrive it and overheat it.

The minikit does have spot on it to put a pi-attenuator. I calculate I need to attenuate by 6dB, so 1/4 of the power or 4mW input.

We calculated a pi-attenuator with 150R resistors on in parallel connected by a 39R resistor should give roughly 6dB attenuation. Now I need to find these in my boxes of bits!

You can see the calculation using this online RF Pi Attenuator Calculator