Satellites have max 20 watts transmit!

Just saw this statistic in a NASA video about the Deep Space Array.
Turns out that due to limitations in power gathering, etc. satellites transmit power is only about 20 watts! That is true even for deep space probes which have already breached the limits of the solar system.


Imagine being able to see a 20 watt light bulb at Saturn from here.
TBF, antennas are often described as "high gain" so I’m not sure Geoff was speaking purely about active amplification.

With up to 70m wide dishes, I’m sure those antennas are of extremely high gain, not to mention the digital signal processing and at least some electronic gain that occurs down the pipeline.

Bingo! Arecibo antenna in Puerto Rico is another good example, with diameter of 305m. And the very large log period HF antennas on certain US buildings. The satellite link budget equations I worked with were so long it took a whole page to write them out. 
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The Arecibo antenna is a radio telescope though, not really used for routine satellite monitoring, is it?

Good news, after Hurricane Maria damaged it, it will now get a 5.8 million dollar upgrade.