How does the galactic background compare to the radio waves from Jupiter and Saturn?

Galactic synchrotron radiation is distributed across the Milky Way, whereas the emission from planets is localized.

So which is stronger depends on the beamsize of your telescope.

The radio spectrum of most planets, including Saturn, dies off at frequencies as high as 1 MHz, whereas the spectrum of Jupiter peaks at around 30 MHz, a frequency that can propagate through the ionosphere of the Earth and be detected from the ground.

The radio spectrum of Jupiter has a couple peaks, especially the peak at 30 MHz, whereas Galactic synchrotron emission has a smooth spectrum that reaches up to tens of GHz.

The galactic background noise is significantly red shifted.