I'd have to go through a lot of webpages [even employing e-mail] to find out what frequencies each deepspace mission uses, and if such spacecraft employ multi-frequency
transmitters [they probably do]. There are alot of space missions up there using the DSN, as a brief visit to the DSN website will show.
You'd have just as much luck finding out as I.

Still, I wouldn't be surprised to learn that multiband transmissions might be employed by various deepspace craft.
Data compression may also be used; It was used during the Galileo Jupiter-orbiting mission.
I'm certainly no expert in electronics. But I do have a handle on some of the basics.
cheers.

Jacob