I used to think the Proton packs were what filled up the roof rack on the Ghostbuster's Ecto-1 vehicle, but that turns out to not be the case. What is the equipment on the roof of the car supposed to do? Is it just window dressing, or is there an unstated canon reason for it? An explanation from the comics or the animated series would be fine, but I'm hoping for a movie answer.
In the original 'Ghostbuster' franchise films, the rig and equipment on the top of the Ectomobile or Ecto-1 was never used or revealed.
Considering the cost of the fabrication and the rebuild by Steve Dane, credited as a Hardware Consultant, it was considered a miracle the car moved at all. The equipment on the car was never meant to be used by the actors.
In a subsequent cartoon, a proton cannon (an upgraded and more powerful version of the proton pack) was said to be on top of the Ecto-1.
Different and subsequent versions of the vehicle (comics, cartoons) all report different versions of said equipment rack.
The Ectomobile, or Ecto–1 is a 1959 Cadillac Miller-Meteor limo-style endloader combination car (ambulance conversion) used in the 1984 film Ghostbusters and other Ghostbusters fiction. The original vehicle design was the creation of Steven Dane, credited as a Hardware Consultant in the credits.
In the original movie, Stantz pays $4800 (over $9900 in 2012 dollars) for it and claims it needs a plethora of repairs. In Stantz's own words, it needs "suspension work and shocks, brakes, brake pads, lining, steering box, transmission, rear end... new rings, mufflers, a little wiring...."
After the necessary reconstruction, it is used to carry the Ghostbusters and their ghost-capturing equipment through New York City. Its features include a special pull-out rack in the rear containing the staff's proton packs. There are also various gadgets mounted on the top, whose function is never revealed in the movies. A cartoon episode features the proton cannon, presumably a more powerful version of a proton pack, mounted on top for use against extra large or even giant sized paranormal entities.
Other versions of the Ecto-1 are seen in various media depictions, some giving the vehicle equipment upgrades:
In the 1984 computer game adaptation, players are given the choice between the 1963 hearse (which looked the most like Ecto-1), a cheap VW Beetle, a spacious station wagon and a high performance (but low-capacity) sports car.
Ecto-1a is an upgraded version of the Ecto-1, seen only in Ghostbusters II, which includes more technical equipment on the vehicle's roof and digital announcement boards on each side of it. The logo is updated and added to the hood. The vehicle also sports strips of yellow and black along either side.
Ecto-1b is featured in Ghostbusters: The Video Game; the 1b is similar to the 1a, but features upgraded equipment and the addition of the Super Slammer Trap, an enhanced capacity ghost trap, on its roof.
And many others...
- The Ecto-1 in the original script was said to have had supernatural abilities allowing it to dematerialize allowing the Ghostbusters to evade the police. The subsequent rewrite removed said abilities.
Harold Ramis recounts: "The encounter between the policeman and the Ectomobile is the only scene in the final shooting script which suggested that the vehicle itself had some extranormal powers -- a carryover from Dan Aykroyd's initial draft in which the Ectomobile was equipped with an advanced dematerializing capability that allowed its operators, functioning somewhat outside the law, to readily elude police pursuit." - Shay, Don (November 1985). Making Ghostbusters, p. 95 annotation. New York Zoetrope, New York NY USA, ISBN 0918432685.
- The Ecto-1 was truly in terrible shape. In Ghostbuster II when the car was smoking and having difficulties, it was because the car was, in fact, breaking down. The car finally died on the Brooklyn Bridge and was cited and towed because there are no breakdown lanes on the bridge. The car obstructed traffic for hours.
The Milne novelisation of the film ("Ghostbusters") simply states that the top of the Ecto-1 has communications equipment on it:
A flashing purple-and-white strobe display lights up the dingy back alleys. Communication antennae spin on the roof. On the doors, the Friendly Ghost symbol is emblazoned in red and white.
The Mueller novelisation of the film ("Ghostbusters: The Supernatural Spectacular") goes a little further:
“Will you get a move on here, Egon?” Venkman cried from the passenger side. “You're driving.”
“What’s wrong with Ray?”
“He dented his bumper. Let’s go.”
With a blaze of lights the old Cadillac’s motor roared to life, the banks of rooftop sensors, antennae, and microwave transmitters swinging to alertness. Janine triggered the door opener, Venkman hit the siren, and they were off.
You can see some of these features on this "concept art" by the film's Hardware Consultant Stephen Dane:
What's described as a TV antenna in the diagram, was called a "diavariable universal" by Egon in the Real Ghostbusters episode "I Am The City" also written by Richard Mueller.
I used to have a technical manual that I believe came out in '85 or '86 and it said the top roof equipment was as follows:
Bio fuel/hydrogen fuel cell system and Main Fuel booster Enhances fuel range
Geophone Ecto Accostic Device senses Ecto vibrations or demintional shifts.
Enhanced Paranormal Ecto-kinetic Activity metrer (EPKE meter) Detects paranormal activity for twelve blocks
Fuel/Air scrubbing system to reduce emissions.
On the Bluray extras Aykroyd states that part of the roof equipment contains muon scrubbers.
That would make sense as in the canon the traps use muon decay in their functioning as seen here.
It could mean that the equipment scrubs excess muon traces from them. That could also be what the yellow hose in the pants is for. Some sort of portable muon scrubbing equipment when not near the ectomobile.