Cheap easy way to test for RF power output
One idea might be to look at this site. https://sites.google.com/site/lofturj/ad8307-power-meter

The power meter is based on the AD8307 logarithmic amp and the circuit handles powers up to 500W / 500MHz with the aid of a 40dB power tap. 

The rest of the circuit is basically measuring the voltage produced and displaying it but you could just use a digital voltmeter.