According to the Haynes Owner's Workshop Manual for the Millennium Falcon, the ship is equipped with a military grade rectenna dish. In fact, the first time we see the Falcon in Docking bay 94... wait... there is no dish!
Since only about half of this set was constructed, the dish was never built for A New Hope. Presumably the intention was to extend the set with a matte painting in post production, and maybe they never got around to it. I remember thinking as a child that the dish was probably somehow able to fold down into the hull, but that seems kind of silly now. Anyway, for the rest of the film, the ship has a rectenna dish which you can see here:
The dish on the 5 foot filming miniature is posable, and one of the interesting things I noticed in my research is that at some point between the filming of A New Hope and now, the dish was flipped around completely. Take a look at this screen grab from ANH and this photograph from around the same time.
It's a little difficult to tell from these images but if you look closely you can see that the dish has 2 patches of grey paint on either side of the dish; small on the left and large on the right. This modern photo shows that the large grey patch is on the left and the small is on the right, meaning that the dish was flipped over to face the back and around to face the front again.
My suspicion is that it happened after this photoshoot which has the dish looking super goofy pointed straight up.
The dish is famously knocked off in Return of the Jedi when Lando is flying through the superstructure of the second Death Star. Not a scratch, my ass!
The damaged round dish gets replaced sometime before The Force Awakens with a new rectangular dish. I affectionately refer to this dish as the "snow shovel." The Haynes manual has a diagram of a similar looking dish and calls it a standard CEC (Corellian Engineering Corp for you non-nerds out there) civilian model sensor dish.
Another bit of trivia is that this dish is based on the dish from the Tantive IV Blockade runner. This ship was originally intended to be the Millennium Falcon but similarities to Space 1999's Eagle Transporter prompted a design change.
Incidentally, ILM legend Bill George recently posted on his Sci-Fi Airshow website a model he created that is essentially the lovechild of the original Falcon design and the Eagle Transporter, The Millennium Eagle. His page includes more history on the initial Falcon design that would become the Blockade Runner and a link to even more Falcon history!
ANYWAY, the dish was one of the first detailed parts I worked on for my build, and was based on this diagram from the Star Wars Blueprints book:
Here is a behind the scenes image from the Empire Strikes Back of Lando rescuing Luke that features this setpiece:
I built the radial details on the front of the dish based on the diagram above, but on the filming miniature many of them come from the Aurora Sealab model kit (see below). I had also initially modeled the concentric rings seen in the image above, but left them out feeling the model looked too busy with them. Here are some beauty shots of my dish (note that it's been rotated to it's original ANH position).
I also put together a diagram of the greebles on the dish that have been identified. This information is available on Gort's Kit ID thread but since I've kept track of this stuff I figured I would share here. Addtional parts were identified by Lee Malone of Rogue Studio Productions.
Thanks again for reading! I'll leave you with a render of our progress so far.
p.s. I want to thank RPF user Jaitea for color correcting these classic shots of the Falcon recently. I really enjoyed them!
Next time: Docking Rings