Measuring power at these frequencies is not always easy. Bird slugs are difficult to find in high power @ 23 cm. We acquired a Plisch output filter and found two very nice directional couplers, on the input and the output.We decided to cut off the couplers from the filters, and install 7/16 connectors on them. After doing so, we calibrated the couplers with a network analyzer, so we are sure the output coupling is - 40 dB at exactly 1296 MHz. 

Now we can use a spectrum analyzer or a microwave power meter, to measure TX power to its exact value. Also, we have a nice sample output to mesure the carrier.