External Power Amplifiers

@mikos Cheap usually means that it will have an generic MMIC on it with the part number sanded off. They do this to stop even cheaper lower quality clones. And it probably only has a few vias or even no vias at all between the ground planes. Or else it will be missing the second ground plane altogether. With high resolution photos of both sides of the board you can usually tell a lot about the build quality. If the photos are blurred or very low quality don’t buy it is a very good rule of thumb, for cheap.

If you were planning to use a PA as the last RX stage for some extremely weak signals be careful to add an attenuator, to bring signals levels well under the devices maximum (10dB or more under the maximum is a good safe level to aim for or below, to avoid damage) What is the Maximum RX input power (before damage)?
Antenna->(BPF)->LNA->Cable->PA->Attenuator->(BPF)->Receiver.
Its noise figure will be very bad, but as a very last amplifier stage the signal levels “should” be above it’s noise floor.

Or maybe just stick to the more traditional TX configuration of a PA:
Transmitter->BPF->PA->Cable->Antenna
And with a SDR Transmitter be sure to have the signal that you want to off centre well away from the DC spike. And have the DC spike well inside the attenuation band of your Band Pass Filter, so that you are not transmitting the DC spike.